REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is hereby made to U.S. Provisional Patent Application Ser. No. 60/853,411, filed Oct. 19, 2006, entitled AUTOMATIC INJECTION DEVICE, the contents of which are hereby incorporated by reference and priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i). 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to automatic injection devices for hypodermic syringes generally. 
       BACKGROUND OF THE INVENTION 
       [0000]    
       
         
           
             The following U.S. patents are believed to represent the current state of the art: U.S. Pat. Nos. 4,474,572; 4,475,906; 4,484,910; 4,487,602; 4,505,710; 4,512,767; 4,515,590; 4,518,387; 4,529,401; 4,529,403; 4,530,695; 4,534,759; 4,547,189; 4,553,962; 4,573,970; 4,573,976; 4,578,061; 4,578,064; 4,580,561; 4,592,744; 4,594,073; 4,596,558; 4,597,753; 4,600,403; 4,601,708; 4,613,328; 4,620,540; 4,620,847; 4,624,660; 4,650,468; 4,658,830; 4,659,326; 4,664,651; 4,664,654; 4,666,436; 4,672,967; 4,681,565; 4,687,465; 4,687,467; 4,689,042; 4,699,614; 4,710,170; 4,723,937; 4,735,618; 4,738,663; 4,743,234; 4,744,955; 4,745,907; 4,747,829; 4,747,831; 4,753,636; 4,755,169; 4,758,227; 4,758,230; 4,758,231; 4,766,908; 4,767,407; 4,767,413; 4,770,655; 4,781,683; 4,781,685; 4,781,688; 4,784,640; 4,787,384; 4,787,893; 4,790,823; 4,790,827; 4,795,432; 4,795,433; 4,798,587; 4,799,921; 4,804,370; 4,808,169; 4,813,937; 4,813,940; 4,820,275; 4,820,286; 4,826,484; 4,826,489; 4,826,490; 4,828,548; 4,832,682; 4,832,693; 4,834,704; 4,834,718; 4,842,598; 4,846,811; 4,850,961; 4,850,968; 4,850,971; 4,850,976; 4,850,977; 4,850,994; 4,861,338; 4,863,427; 4,863,435; 4,863,436; 4,865,592; 4,874,372; 4,874,382; 4,883,466; 4,883,472; 4,886,499; 4,887,998; 4,892,107; 4,892,523; 4,894,054; 4,894,055; 4,898,589; 4,900,303; 4,900,307; 4,900,311; 4,902,279; 4,904,242; 4,906,236; 4,908,022; 4,909,794; 4,909,795; 4,911,706; 4,913,702; 4,915,702; 4,917,672; 4,919,146; 4,919,657; 4,923,443; 4,923,445; 4,927,414; 4,929,237; 4,929,241; 4,931,040; 4,932,944; 4,932,946; 4,932,947; 4,935,013; 4,935,014; 4,936,830; 4,941,879; 4,944,723; 4,944,725; 4,946,441; 4,950,240; 4,950,241; 4,950,250; 4,950,252; 4,955,866; 4,955,868; 4,955,869; 4,955,870; 4,961,728; 4,966,589; 4,966,592; 4,966,593; 4,973,310; 4,973,317; 4,976,704; 4,988,335; 4,988,339; 4,994,045; 4,998,921; 4,998,922; 5,000,736; 5,000,737; 5,002,548; 5,007,903; 5,011,475; 5,015,240; 5,017,187; 5,019,043; 5,019,044; 5,019,047; 5,019,048; 5,021,059; 5,024,665; 5,026,349; 5,030,208; 5,034,003; 5,037,306; 5,037,382; 5,037,393; 5,037,400; 5,041,094; 5,042,977; 5,045,066; 5,047,016; 5,049,133; 5,049,136; 5,053,010; 5,053,018; 5,055,102; 5,057,086; 5,057,089; 5,059,180; 5,059,185; 5,061,249; 5,061,251; 5,064,419; 5,067,490; 5,067,948; 5,071,353; 5,080,104; 5,084,027; 5,084,029; 5,084,030; 5,085,640; 5,085,641; 5,085,642; 5,088,986; 5,088,988; 5,092,843; 5,092,851; 5,092,852; 5,092,853; 5,098,382; 5,098,400; 5,098,401; 5,102,393; 5,102,397; 5,104,378; 5,104,380; 5,104,384; 5,104,385; 5,106,370; 5,106,372; 5,106,379; 5,108,378; 5,108,379; 5,112,307; 5,112,316; 5,114,404; 5,120,310; 5,120,314; 5,120,321; 5,122,118; 5,122,124; 5,125,898; 5,125,899; 5,127,910; 5,135,507; 5,135,510; 5,137,515; 5,137,516; 5,141,496; 5,143,414; 5,147,311; 5,147,326; 5,147,327; 5,149,323; 5,152,751; 5,156,599; 5,160,326; 5,163,916; 5,163,917; 5,163,918; 5,167,632; 5,167,641; 5,169,389; 5,169,392; 5,176,641; 5,176,655; 5,176,656; 5,176,657; 5,183,468; 5,183,469; 5,188,614; 5,190,526; 5,193,552; 5,195,982; 5,195,983; 5,195,985; 5,199,952; 5,201,708; 5,201,710; 5,205,826; 5,205,827; 5,207,646; 5,207,699; 5,209,739; 5,211,628; 5,211,629; 5,215,524; 5,215,533; 5,215,534; 5,215,535; 5,215,536; 5,217,437; 5,219,338; 5,221,262; 5,222,943; 5,222,947; 5,222,974; 5,224,936; 5,226,882; 5,228,883; 5,232,457; 5,232,458; 5,238,654; 5,242,388; 5,242,401; 5,242,416; 5,242,420; 5,246,428; 5,250,031; 5,256,152; 5,257,976; 5,261,894; 5,263,933; 5,267,961; 5,267,963; 5,269,761; 5,269,762; 5,269,766; 5,273,532; 5,273,538; 5,273,539; 5,273,541; 5,273,544; 5,279,554; 5,279,566; 5,279,577; 5,279,579; 5,279,581; 5,279,582; 5,279,583; 5,279,590; 5,282,793; 5,282,822; 5,282,827; 5,284,479; 5,290,233; 5,290,239; 5,290,240; 5,290,254; 5,292,314; 5,295,963; 5,295,965; 5,295,972; 5,295,973; 5,295,974; 5,295,975; 5,300,029; 5,300,030; 5,300,040; 5,300,045; 5,304,137; 5,304,138; 5,306,251; 5,306,258; 5,308,332; 5,311,841; 5,312,353; 5,312,366; 5,312,368; 5,312,370; 5,312,371; 5,312,372; 5,314,503; 5,318,538; 5,320,609; 5,322,517; 5,324,265; 5,328,475; 5,328,482; 5,328,484; 5,330,430; 5,334,149; 5,334,158; 5,334,173; 5,336,180; 5,336,187; 5,336,199; 5,338,303; 5,338,311; 5,342,310; 5,342,320; 5,344,407; 5,344,408; 5,346,475; 5,346,480; 5,346,481; 5,348,544; 5,352,200; 5,352,202; 5,352,203; 5,354,287; 5,356,387; 5,358,489; 5,360,410; 5,364,362; 5,364,370; 5,366,447; 5,368,568; 5,368,570; 5,368,571; 5,370,619; 5,370,626; 5,374,250; 5,378,240; 5,383,857; 5,385,550; 5,385,551; 5,385,557; 5,389,076; 5,389,085; 5,391,151; 5,391,183; 5,395,317; 5,395,337; 5,399,163; 5,401,246; 5,401,249; 5,401,251; 5,403,286; 5,403,287; 5,405,326; 5,405,327; 5,407,436; 5,409,466; 5,411,487; 5,415,638; 5,415,645; 5,415,648; 5,419,766; 5,419,773; 5,423,746; 5,425,715; 5,425,722; 5,429,611; 5,429,612; 5,429,613; 5,431,631; 5,431,632; 5,433,712; 5,445,618; 5,445,620; 5,451,210; 5,458,576; 5,458,580; 5,460,611; 5,462,531; 5,466,223; 5,468,227; 5,474,687; 5,478,314; 5,478,316; 5,478,328; 5,480,385; 5,480,387; 5,480,390; 5,482,039; 5,484,414; 5,486,163; 5,486,164; 5,487,732; 5,487,733; 5,487,734; 5,489,272; 5,492,536; 5,496,278; 5,501,672; 5,512,048; 5,512,050; 5,514,097; 5,514,107; 5,520,639; 5,520,649; 5,522,797; 5,522,812; 5,527,283; 5,527,284; 5,527,307; 5,529,189; 5,531,691; 5,531,692; 5,531,694; 5,531,704; 5,531,706; 5,533,975; 5,533,984; 5,536,243; 5,536,253; 5,536,257; 5,538,506; 5,538,508; 5,540,664; 5,540,666; 5,542,920; 5,542,927; 5,549,558; 5,549,568; 5,549,570; 5,549,572; 5,549,708; 5,558,648; 5,562,623; 5,562,624; 5,562,626; 5,562,631; 5,569,202; 5,569,203; 5,573,513; 5,575,770; 5,578,011; 5,578,014; 5,578,015; 5,582,591; 5,586,976; 5,591,133; 5,591,134; 5,591,138; 5,593,387; 5,593,390; 5,599,309; 5,599,313; 5,599,316; 5,599,318; 5,601,532; 5,601,535; 5,605,544; 5,609,577; 5,611,781; 5,611,782; 5,613,500; 5,613,951; 5,613,952; 5,615,771; 5,616,123; 5,616,132; 5,616,134; 5,616,135; 5,620,422; 5,620,425; 5,624,401; 5,624,405; 5,628,765; 5,630,803; 5,632,730; 5,632,733; 5,634,906; 5,634,909; 5,634,937; 5,637,092; 5,637,094; 5,643,220; 5,643,222; 5,647,851; 5,649,622; 5,651,774; 5,653,687; 5,653,688; 5,653,693; 5,656,031; 5,658,256; 5,658,257; 5,658,258; 5,658,259; 5,662,610; 5,662,617; 5,665,071; 5,665,075; 5,669,889; 5,672,155; 5,672,161; 5,681,291; 5,681,295; 5,688,240; 5,688,251; 5,693,016; 5,693,022; 5,693,023; 5,695,472; 5,704,911; 5,704,921; 5,707,393; 5,709,662; 5,709,667; 5,709,668; 5,713,866; 5,713,871; 5,713,872; 5,720,727; 5,725,498; 5,738,655; 5,741,223; 5,743,879; 5,743,887; 5,743,888; 5,743,891; 5,746,718; 5,749,854; 5,749,860; 5,755,692; 5,769,822; 5,769,827; 5,779,675; 5,779,677; 5,779,684; 5,788,677; 5,788,713; 5,792,107; 5,792,121; 5,792,122; 5,795,336; 5,797,885; 5,800,403; 5,807,334; 5,807,345; 5,807,352; 5,810,775; 5,810,784; 5,817,054; 5,817,070; 5,820,602; 5,823,997; 5,823,998; 5,827,293; 5,830,130; 5,836,911; 5,836,920; 5,843,036; 5,843,047; 5,848,990; 5,851,197; 5,853,390; 5,853,393; 5,855,839; 5,858,000; 5,865,227; 5,865,804; 5,868,711; 5,879,337; 5,882,342; 5,885,257; 5,891,052; 5,891,092; 5,891,097; 5,891,105; 5,897,508; 5,899,885; 5,899,886; 5,908,404; 5,908,408; 5,910,131; 5,911,706; 5,919,166; 5,921,959; 5,921,960; 5,921,961; 5,921,963; 5,921,964; 5,925,019; 5,928,188; 5,928,194; 5,928,205; 5,931,813; 5,938,638; 5,938,639; 5,941,850; 5,944,692; 5,944,693; 5,951,522; 5,954,699; 5,957,892; 5,957,895; 5,957,897; 5,960,797; 5,961,491; 5,971,953; 5,976,111; 5,980,487; 5,980,488; 5,980,491; 5,980,494; 5,984,899; 5,984,900; 5,989,219; 5,989,221; 5,993,417; 5,993,418; 5,997,500; 5,997,511; 5,997,513; 6,001,080; 6,007,474; 6,010,486; 6,010,487; 6,015,396; 6,015,438; 6,017,325; 6,022,337; 6,033,386; 6,033,387; 6,036,674; 6,039,713; 6,050,974; 6,050,977; 6,056,716; 6,056,724; 6,056,734; 6,063,040; 6,063,053; 6,066,115; 6,068,616; 6,074,360; 6,074,369; 6,074,370; 6,077,245; 6,080,135; 6,083,199; 6,083,200; 6,086,562; 6,086,569; 6,090,077; 6,090,078; 6,090,080; 6,093,172; 6,099,500; 6,099,503; 6,099,504; 6,102,844; 6,113,574; 6,117,112; 6,117,113; 6,126,637; 6,129,710; 6,142,972; 6,149,626; 6,149,629; 6,156,008; 6,156,010; 6,156,013; 6,156,015; 6,159,161; 6,159,181; 6,159,185; 6,171,284; 6,179,812; 6,183,444; 6,183,446; 6,186,980; 6,192,891; 6,193,695; 6,206,856; 6,206,857; 6,210,369; 6,217,550; 6,217,559; 6,221,044; 6,221,051; 6,221,052; 6,224,576; 6,228,054; 6,228,055; 6,235,006; 6,241,707; 6,241,708; 6,254,575; 6,254,580; 6,258,056; 6,261,264; 6,261,265; 6,267,748; 6,270,472; 6,270,481; 6,273,870; 6,280,399; 6,280,420; 6,280,421; 6,283,941; 6,293,925; 6,299,601; 6,309,374; 6,309,375; 6,312,409; 6,315,113; 6,319,233; 6,319,234; 6,322,536; 6,325,781; 6,325,789; 6,331,173; 6,332,875; 6,344,031; 6,356,783; 6,361,525; 6,368,303; 6,371,938; 6,379,336; 6,387,078; 6,402,716; 6,409,701; 6,409,703; 6,409,706; 6,412,490; 6,413,236; 6,413,237; 6,416,323; 6,416,497; 6,419,658; 6,428,463; 6,428,517; 6,432,035; 6,432,082; 6,432,087; 6,436,068; 6,440,098; 6,443,929; 6,447,480; 6,454,743; 6,458,105; 6,461,331; 6,461,333; 6,468,247; 6,475,194; 6,478,780; 6,482,176; 6,485,469; 6,485,474; 6,494,863; 6,500,155; 6,508,755; 6,511,454; 6,514,230; 6,517,516; 6,517,517; 6,524,278; 6,527,734; 6,527,742; 6,530,896; 6,530,904; 6,537,249; 6,537,252; 6,544,234; 6,547,764; 6,551,275; 6,551,276; 6,551,278; 6,554,798; 6,558,351; 6,558,357; 6,565,533; 6,565,538; 6,569,115; 6,572,584; 6,572,585; 6,575,939; 6,579,256; 6,582,405; 6,584,910; 6,585,690; 6,585,693; 6,585,702; 6,589,158; 6,592,508; 6,592,555; 6,592,556; 6,595,962; 6,599,268; 6,599,269; 6,599,272; 6,605,058; 6,605,067; 6,605,073; 6,607,508; 6,607,509; 6,613,019; 6,613,022; 6,616,630; 6,616,638; 6,616,639; 6,620,136; 6,620,137; 6,620,138; 6,623,455; 6,623,458; 6,623,459; 6,626,864; 6,629,957; 6,629,959; 6,632,198; 6,637,587; 6,638,248; 6,638,255; 6,641,561; 6,645,181; 6,652,482; 6,656,164; 6,659,975; 6,659,982; 6,663,593; 6,669,666; 6,673,034; 6,673,044; 6,673,049; 6,678,550; 6,679,863; 6,679,864; 6,685,676; 6,685,677; 6,689,091; 6,689,106; 6,689,107; 6,689,108; 6,692,470; 6,692,471; 6,699,218; 6,702,784; 6,706,011; 6,706,015; 6,706,019; 6,709,416; 6,712,787; 6,712,788; 6,716,191; 6,716,197; 6,716,198; 6,719,721; 6,719,728; 6,719,730; 6,723,068; 6,723,072; 6,726,655; 6,726,658; 6,726,661; 6,726,662; 6,730,059; 6,736,800; 6,740,059; 6,743,203; 6,749,833; 6,752,782; 6,752,784; 6,752,798; 6,761,706; 6,767,336; RE 33,585; RE 34,335; RE 34,936; RE 36,398; RE 36,447; RE 37,110; RE 37,252 and RE 37,487. 
           
         
       
     
       SUMMARY OF THE INVENTION 
       [0004]    The present invention seeks to provide an improved automatic injection device. 
         [0005]    There is thus provided in accordance with a preferred embodiment of the present invention an injection device for injecting a fluid into an object, the injection device including a plunger assembly for operative engagement with a syringe adapted to contain the fluid and permit ejection of the fluid therefrom via a syringe outlet, the plunger assembly being displaceable in a first direction which causes at least some of the fluid contained in the syringe to be ejected from the syringe via the syringe outlet and an inadvertent fluid ejection prevention assembly coupled to the plunger assembly for preventing ejection of fluid from the syringe in situations where the syringe outlet is neither in operative engagement with a vial adaptor suitable for providing fluid communication with the interior of a vial nor in fluid communication with an injection site within the object. 
         [0006]    In accordance with a preferred embodiment of the present invention the plunger assembly is adapted for displacement also in a second direction opposite to the first direction. Preferably, the injection device also includes a user operable actuator button, which, when displaced in a button displacement direction, is operable to enable displacement of the plunger assembly in the first direction, the user operable actuator button normally being displaceable in the button displacement direction only when the syringe outlet is in operative engagement with the injection site. Additionally or alternatively, the inadvertent fluid ejection prevention assembly includes a vial adaptor engagement assembly which is displaceable responsive to operative engagement with the vial adaptor to an operative orientation which enables the plunger assembly to be displaced in the first direction. 
         [0007]    There is further provided in accordance with a further preferred embodiment of the present invention an automatic injection device for injecting a fluid into an object, the automatic injection device including a plunger assembly for operative engagement with a syringe adapted to contain the fluid and permit ejection of the fluid therefrom via a syringe outlet, the plunger assembly being displaceable in a first direction which causes at least some of the fluid contained in the syringe to be ejected from the syringe via the syringe outlet and a user operable actuator button which, when displaced in a button displacement direction, is operable to cause displacement of the plunger assembly in the first direction, the user operable actuator button being mechanically locked against displacement in the button displacement direction when the syringe outlet is in operative engagement with a vial adaptor. 
         [0008]    In accordance with a preferred embodiment of the present invention the plunger assembly is adapted for displacement also in a second direction opposite to the first direction. Preferably, the automatic injection device also includes a vial adaptor engagement assembly which is displaceable responsive to operative engagement with the vial adaptor to an operative orientation which enables the plunger assembly to be displaced in the first direction. 
         [0009]    There is additionally provided in accordance with an additional preferred embodiment of the present invention an automatic injection device for injecting a fluid into an object, the automatic injection device including a plunger assembly for operative engagement with a syringe adapted to contain the fluid and permit ejection of the fluid therefrom via a syringe outlet, the plunger assembly being displaceable in a first direction which causes at least some of the fluid contained in the syringe to be ejected from the syringe via the syringe outlet and an inadvertent fluid ejection prevention assembly coupled to the plunger assembly and including a vial adaptor engagement assembly which is displaceable responsive to operative engagement with a vial adaptor to an operative orientation which enables the plunger assembly to be displaced in the first direction. 
         [0010]    In accordance with a preferred embodiment of the present invention the vial adaptor engagement assembly includes a needle guard. Preferably, the automatic injection device also includes a selectable driving assembly operative, when actuated by a user, to drive the plunger assembly in the first direction, and wherein the inadvertent fluid ejection prevention assembly includes a locking assembly operative to lock the plunger assembly against displacement in the first direction and to permit displacement of the plunger assembly in a second direction, opposite to the first direction. 
         [0011]    In accordance with another preferred embodiment of the present invention, the automatic injection device also includes a user operable actuation button operative when pressed by a user to generally simultaneously unlock the plunger assembly and unlock the selectable driving assembly. Additionally or alternatively, the vial adaptor engagement assembly includes a connector rod which provides mechanical interaction between the vial adaptor and the locking assembly. Preferably, the plunger assembly is adapted for displacement also in a second direction opposite to the first direction. 
         [0012]    There is also provided in accordance with another preferred embodiment of the present invention an injection device for injecting a fluid into an object, the injection device including a plunger assembly for operative engagement with a syringe adapted to contain the fluid and permit ejection of the fluid therefrom via a syringe outlet, the plunger assembly being displaceable in a first direction, which causes at least some of the fluid contained in the syringe to be ejected from the syringe via the syringe outlet, and in a second direction opposite to the first direction, a selectable driving assembly operative, when actuated by a user, to drive the plunger assembly in the first direction, a first locking assembly operative to lock the plunger assembly against displacement in the first direction and to permit displacement of the plunger assembly in the second direction and a second locking assembly operative to lock the selectable driving assembly against displacement in the first direction. 
         [0013]    In accordance with a preferred embodiment of the present invention, the injection device also includes a user operable actuation button operative when pressed by the user to generally simultaneously unlock the plunger assembly and unlock the selectable driving assembly. Preferably, the injection device also includes a vial adaptor engagement assembly which is displaceable responsive to operative engagement with a vial adaptor to an operative orientation which enables the plunger assembly to be displaced in the first direction. 
         [0014]    In accordance with another preferred embodiment of the present invention the vial adaptor engagement assembly includes a connector rod which provides mechanical interaction between the vial adaptor and the first locking assembly. Additionally or alternatively, the vial adaptor engagement assembly includes a needle guard which provides mechanical interaction between the vial adaptor and the first locking assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0016]      FIG. 1  is a simplified exploded view illustration of an automatic injection device constructed and operative in accordance with a preferred embodiment of the present invention; 
           [0017]      FIG. 2  is a simplified pictorial illustration of a drug vial adaptor which forms part of the automatic injection device of  FIG. 1 ; 
           [0018]      FIGS. 3A and 3B  are respective top and side view simplified planar illustrations of the drug vial adaptor of  FIG. 2 ; 
           [0019]      FIGS. 4A and 4B  are sectional illustrations taken along respective section lines and directions IVA-IVA and IVB-IVB in  FIGS. 3A and 3B ; 
           [0020]      FIG. 5  is a simplified pictorial illustration of a needle guard element which forms part of the automatic injection device of  FIG. 1 ; 
           [0021]      FIGS. 6A and 6B  are respective top and side view simplified planar illustrations of the needle guard element of  FIG. 5 ; 
           [0022]      FIGS. 7A and 7B  are sectional illustrations taken along respective section lines and directions VIIA-VIIA and VIIB-VIIB in  FIGS. 6A and 6B ; 
           [0023]      FIG. 8  is a simplified pictorial illustration of a forward housing which forms part of the automatic injection device of  FIG. 1 ; 
           [0024]      FIGS. 9A ,  9 B and  9 C are respective top, side and front view simplified planar illustrations of the forward housing of  FIG. 8 ; 
           [0025]      FIGS. 10A ,  10 B and  10 C are sectional illustrations taken along respective section lines and directions XA-XA, XB-XB and XC-XC in  FIGS. 9A and 9B ; 
           [0026]      FIG. 11  is a simplified pictorial illustration of a selectable driving assembly which forms part of the automatic injection device of  FIG. 1 ; 
           [0027]      FIGS. 12A and 12B  are respective top and side view simplified planar illustrations of the selectable driving assembly of  FIG. 11 ; 
           [0028]      FIGS. 13A and 13B  are sectional illustrations taken along respective section lines and directions XIIIA-XIIIA and XIIIB-XIIIB in  FIGS. 12A and 12B ; 
           [0029]      FIG. 14  is a simplified pictorial illustration of a rear housing which forms part of the automatic injection device of  FIG. 1 ; 
           [0030]      FIGS. 15A ,  15 B and  15 C are respective top, side and rear view simplified planar illustrations of the rear housing of  FIG. 14 ; 
           [0031]      FIGS. 16A ,  16 B and  16 C are sectional illustrations taken along respective section lines and directions XVIA-XVIA, XVIB-XVIB and XVIC-XVIC in  FIGS. 15A and 15B ; 
           [0032]      FIGS. 17A and 17B  are respective front and back view simplified pictorial illustrations of an actuation button which forms part of the automatic injection device of  FIG. 1 ; 
           [0033]      FIGS. 18A and 18B  are respective top and side view simplified planar illustrations of the actuation button of  FIGS. 17A and 17B ; 
           [0034]      FIGS. 19A and 19B  are sectional illustrations taken along respective section lines and directions XIXA-XIXA and XIXB-XIXB in  FIGS. 18A and 18B ; 
           [0035]      FIG. 20  is a simplified pictorial illustration of a plunger locking element which forms part of the automatic injection device of  FIG. 1 ; 
           [0036]      FIGS. 21A ,  21 B,  21 C and  21 D are respective rear, top, front and side view simplified planar illustrations of the plunger locking element of  FIG. 20 ; 
           [0037]      FIGS. 22A and 22B  are sectional illustrations taken along respective section lines and directions XXIIA-XXIIA and XXIIB-XXIIB in  FIG. 211B ; 
           [0038]      FIG. 23  is a simplified pictorial illustration of a rear end element which forms part of the automatic injection device of  FIG. 1 ; 
           [0039]      FIGS. 24A and 24B  are respective top and side view simplified planar illustrations of the rear end element of  FIG. 23 ; 
           [0040]      FIGS. 25A ,  25 B and  25 C are sectional illustrations taken along respective section lines and directions XXVA-XXVA, XXVB-XXVB and XXVC-XXVC in  FIGS. 24A and 24B ; 
           [0041]      FIG. 26  is a simplified pictorial illustration of a locking rod which forms part of the automatic injection device of  FIG. 1 ; 
           [0042]      FIGS. 27A ,  27 B,  27 C,  27 D,  27 E,  27 F,  27 G,  27 H,  27 I,  27 J and  27 K are simplified pictorial illustration of various stages of typical use of the automatic injection device of  FIG. 1 ; 
           [0043]      FIG. 28  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27A  in a pre-use operative orientation; 
           [0044]      FIGS. 29A and 29B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 28 ; 
           [0045]      FIGS. 30A ,  30 B,  30 C,  30 D and  30 E are sectional illustrations taken along respective section lines and directions XXXA-XXXA, XXXB-XXXB, XXXC-XXXC, XXXD-XXXD and XXXE-XXXE in  FIGS. 29A and 29B ; 
           [0046]      FIG. 31  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27B  in a vial connection orientation; 
           [0047]      FIGS. 32A and 32B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 31 ; 
           [0048]      FIGS. 33A ,  33 B,  33 C,  33 D and  33 E are sectional illustrations taken along respective section lines and directions XXXIIIA-XXXIIIA, XXXIIIB-XXXIIIB, XXXIIIC-XXXIIIC, XXXIIID-XXXIIID and XXXIIIE-XXXIIIE in  FIGS. 32A and 32B ; 
           [0049]      FIG. 34  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27C  in a vial pumping orientation; 
           [0050]      FIGS. 35A and 35B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 34 ; 
           [0051]      FIGS. 36A ,  36 B,  36 C,  36 D and  36 E are sectional illustrations taken along respective section lines and directions XXXVIA-XXXVIA, XXXVIB-XXXVIB, XXXVIC-XXXVIC, XXXVID-XXXVID and XXXVIE-XXXVIE in  FIGS. 35A and 35B ; 
           [0052]      FIG. 37  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27D  in a drug vial adaptor removal orientation; 
           [0053]      FIGS. 38A and 38B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 37 ; 
           [0054]      FIGS. 39A ,  39 B,  39 C,  39 D and  39 E are sectional illustrations taken along respective section lines and directions XXXIXA-XXXIXA, XXXIXB-XXXIXB, XXXIXC-XXXIXC, XXXIXD-XXXIXD and XXXIXE-XXXIXE in  FIGS. 38A and 38B ; 
           [0055]      FIG. 40  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27E  in an actuated operative orientation; 
           [0056]      FIGS. 41A and 41B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 40 ; 
           [0057]      FIGS. 42A ,  42 B,  42 C,  42 D and  42 E are sectional illustrations taken along respective section lines and directions XLIIA-XLIIA, XLIIB-XLIIB, XLIIC-XLIIC, XLIID-XLIID and XLIIE-XLIIE in  FIGS. 41A and 41B ; 
           [0058]      FIG. 43  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27F  in a needle penetration, pre-drug delivery operative orientation; 
           [0059]      FIGS. 44A and 44B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 43 ; 
           [0060]      FIGS. 45A ,  45 B,  45 C,  45 D and  45 E are sectional illustrations taken along respective section lines and directions XLVA-XLVA, XLVB-XLVB, XLVC-XLVC, XLVD-XLVD and XLVE-XLVE in  FIGS. 44A and 44B ; 
           [0061]      FIG. 46  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27G  in a drug delivery operative orientation; 
           [0062]      FIGS. 47A and 47B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 46 ; 
           [0063]      FIGS. 48A ,  48 B,  48 C,  48 D and  48 E are sectional illustrations taken along respective section lines and directions XLVIIIA-XLVIIIA, XLVIIIB-XLVIIIB, XLVIIIC-XLVIIIC, XLVIIID-XLVIIID and XLVIIIE-XLVIIIE in  FIGS. 47A and 47B ; 
           [0064]      FIG. 49  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27H  in an immediate post-drug delivery operative orientation; 
           [0065]      FIGS. 50A and 50B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 49 ; 
           [0066]      FIGS. 51A ,  51 B,  51 C,  51 D and  51 E are sectional illustrations taken along respective section lines and directions LIA-LIA, LIB-LIB, LIC-LIC, LID-LID and LIE-LIE in  FIGS. 50A and 50B ; 
           [0067]      FIG. 52  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27I  in its operative orientation as it is being disengaged from the injection site; 
           [0068]      FIGS. 53A and 53B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 52 ; 
           [0069]      FIGS. 54A ,  54 B,  54 C,  54 D and  54 E are sectional illustrations taken along respective section lines and directions LIVA-LIVA, LIVB-LIVB, LIVC-LIVC, LIVD-LIVD and LIVE-LIVE in  FIGS. 53A and 53B ; 
           [0070]      FIG. 55  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27J  in a needle protected operative orientation; 
           [0071]      FIGS. 56A and 56B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 55 ; 
           [0072]      FIGS. 57A ,  57 B,  57 C,  57 D and  57 E are sectional illustrations taken along respective section lines and directions LVIIA-LVIIA, LVIIB-LVIIB, LVIIC-LVIIC, LVIID-LVIID and LVIIE-LVIIE in  FIGS. 56A and 56B ; 
           [0073]      FIG. 58  is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27K  in a needle-shield push back misuse operative orientation; 
           [0074]      FIGS. 59A and 59B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 58 ; 
           [0075]      FIGS. 60A ,  60 B,  60 C,  60 D and  60 E are sectional illustrations taken along respective section lines and directions LXA-LXA, LXB-LXB, LXC-LXC, LXD-LXD and LXE-LXE in  FIGS. 59A and 59B ; 
           [0076]      FIG. 61  is a simplified exploded view illustration of an automatic injection device constructed and operative in accordance with another preferred embodiment of the present invention; 
           [0077]      FIG. 62  is a simplified pictorial illustration of a drug vial adaptor which forms part of the automatic injection device of  FIG. 61 ; 
           [0078]      FIGS. 63A and 63B  are respective top and side view simplified planar illustrations of the drug vial adaptor of  FIG. 62 ; 
           [0079]      FIGS. 64A and 64B  are sectional illustrations taken along respective section lines and directions LXIVA-LXIVA and LXIVB-LXIVB in  FIGS. 63A and 63B ; 
           [0080]      FIG. 65  is a simplified pictorial illustration of a needle guard element which forms part of the automatic injection device of  FIG. 61 ; 
           [0081]      FIGS. 66A and 66B  are respective top and side view simplified planar illustrations of the needle guard element of  FIG. 65 ; 
           [0082]      FIGS. 67A and 67B  are sectional illustrations taken along respective section lines and directions LXVIIA-LXVIIA and LXVIIB-LXVIIB in  FIGS. 66A and 66B ; 
           [0083]      FIG. 68  is a simplified pictorial illustration of a forward housing which forms part of the automatic injection device of  FIG. 61 ; 
           [0084]      FIGS. 69A and 69B  are respective top and side view simplified planar illustrations of the forward housing of  FIG. 68 ; 
           [0085]      FIGS. 70A ,  70 B and  70 C are sectional illustrations taken along respective section lines and directions LXXA-LXXA, LXXB-LAB and LXXC-LXXC in  FIGS. 69A and 69B ; 
           [0086]      FIG. 71  is a simplified pictorial illustration of a selectable driving assembly which forms part of the automatic injection device of  FIG. 61 ; 
           [0087]      FIGS. 72A and 72B  are respective top and side view simplified planar illustrations of the selectable driving assembly of  FIG. 71 ; 
           [0088]      FIGS. 73A and 73B  are sectional illustrations taken along respective section lines and directions LXXIIIA-LXXIIIA and LXXIIIB-LXXIIIB in  FIGS. 72A and 72B ; 
           [0089]      FIG. 74 , is a simplified pictorial illustration of a rear housing which forms part of the automatic injection device of  FIG. 61 ; 
           [0090]      FIGS. 75A and 75B  are respective top and side view simplified planar illustrations of the rear housing of  FIG. 74 ; 
           [0091]      FIGS. 76A ,  76 B and  76 C are sectional illustrations taken along respective section lines and directions LXXVIA-LXXVIA, LXXVIB-LXXVIB and LXXVIC-LXXVIC in  FIGS. 75A and 75B ; 
           [0092]      FIGS. 77A and 77B  are simplified pictorial illustrations of an actuation button which forms part of the automatic injection device of  FIG. 61 ; 
           [0093]      FIGS. 78A and 78B  are respective top and side view simplified planar illustrations of the actuation button of  FIG. 77 ; 
           [0094]      FIGS. 79A and 79B  are sectional illustrations taken along respective section lines and directions LXXIXA-LXXIXA and LXXIXB-LXXIXB in  FIGS. 78A and 78B ; 
           [0095]      FIG. 80  is a simplified pictorial illustration of a plunger locking element which forms part of the automatic injection device of  FIG. 61 ; 
           [0096]      FIGS. 81A ,  81 B,  81 C,  81 D and  81 E are respective top, left side, right side, bottom and front view simplified planar illustrations of the plunger locking element of  FIG. 80 ; 
           [0097]      FIGS. 82A and 82B  are sectional illustrations taken along respective section lines and directions LXXXIIA-LXXXIIA and LXXXIIB-LXXXIIB in  FIGS. 82A and 82B ; 
           [0098]      FIG. 83  is a simplified pictorial illustration of a rear end element which forms part of the automatic injection device of  FIG. 61 ; 
           [0099]      FIGS. 84A and 84B  are respective top and side view simplified planar illustrations of the rear end element of  FIG. 83 ; 
           [0100]      FIGS. 85A ,  85 B and  85 C are sectional illustrations taken along respective section lines and directions LXXXVA-LXXXVA, LXXXVB-LXXXVB and LXXXVC-LXXXVC in  FIGS. 84A and 84B ; 
           [0101]      FIGS. 86A ,  86 B,  86 C,  86 D,  86 E,  86 F,  86 G,  86 H,  86 I,  86 J,  86 K and  86 L are simplified pictorial illustration of various stages of typical use of the automatic injection device of  FIG. 61 ; 
           [0102]      FIG. 87  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86A  in a pre-use operative orientation; 
           [0103]      FIGS. 88A and 88B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 87 ; 
           [0104]      FIGS. 89A ,  89 B,  89 C,  89 D and  89 E are sectional illustrations taken along respective section lines and directions LXXXIXA-LXXXIXA, LXXXIXB-LXXXIXB, LXXXIXC-LXXXIXC, LXXXIXD-LXXXIXD and LXXXIXE-LXXXIXE in  FIGS. 88A and 88B ; 
           [0105]      FIG. 90  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86B  in a vial connection orientation; 
           [0106]      FIGS. 91A and 91B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 90 ; 
           [0107]      FIGS. 92A ,  92 B,  92 C,  92 D and  92 E are sectional illustrations taken along respective section lines and directions XCIIA-XCIIA, XCIIB-XCIIB, XCIIC-XCIIC, XCIID-XCIID and XCIIE-XCIIE in  FIGS. 91A and 91B ; 
           [0108]      FIG. 93  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86C  in a vial pumping orientation; 
           [0109]      FIGS. 94A and 94B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 93 ; 
           [0110]      FIGS. 95A ,  95 B,  95 C,  95 D and  95 E are sectional illustrations taken along respective section lines and directions XCVA-XCVA, XCVB-XCVB, XCVC-XCVC, XCVD-XCVD and XCVE-XCVE in  FIGS. 94A and 94B ; 
           [0111]      FIG. 96  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86D  in a drug vial adaptor removal orientation; 
           [0112]      FIGS. 97A and 97B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 96 ; 
           [0113]      FIGS. 98A ,  98 B,  98 C,  98 D and  98 E are sectional illustrations taken along respective section lines and directions XCVIIIA-XCVIIIA, XCVIIIB-XCVIIIB, XCVIIIC-XCVIIIC, XCVIIID-XCVIIID and XCVIIIE-XCVIIIE in  FIGS. 97A and 97B ; 
           [0114]      FIG. 99  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86E  in an actuated operative orientation; 
           [0115]      FIGS. 100A and 100B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 99 ; 
           [0116]      FIGS. 101A ,  101 B,  101 C,  101 D and  101 E are sectional illustrations taken along respective section lines and directions CIA-CIA, CIB-CIB, CIC-CIC, CID-CID and CIE-CIE in  FIGS. 100A and 100B ; 
           [0117]      FIG. 102  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86F  in an un-actuated operative orientation; 
           [0118]      FIGS. 103A and 103B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 102 ; 
           [0119]      FIGS. 104A ,  104 B,  104 C,  104 D and  104 E are sectional illustrations taken along respective section lines and directions CIVA-CIVA, CIVB-CIVB, CIVC-CIVC, CIVD-CIVD and CIVE-CIVE in  FIGS. 103A and 103B ; 
           [0120]      FIG. 105  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86G  in a needle penetration, pre-drug delivery operative orientation; 
           [0121]      FIGS. 106A and 106B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 105 ; 
           [0122]      FIGS. 107A ,  107 B,  107 C,  107 D and  107 E are sectional illustrations taken along respective section lines and directions CVIIA-CVIIA, CVIIB-CVIIB, CVIIC-CVIIC, CVIID-CVIID and CVIIE-CVIIE in  FIGS. 106A and 106B ; 
           [0123]      FIG. 108  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86H  in a drug delivery operative orientation; 
           [0124]      FIGS. 109A and 109B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 108 ; 
           [0125]      FIGS. 110A ,  110 B,  110 C,  110 D and  110 E are sectional illustrations taken along respective section lines and directions CXA-CXA, CXB-CXB, CXC-CXC, CXD-CXD and CXE-CXE in  FIGS. 109A and 109B ; 
           [0126]      FIG. 111  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86I  in an immediate post-drug delivery operative orientation; 
           [0127]      FIGS. 112A and 112B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 111 ; 
           [0128]      FIGS. 113A ,  113 B,  113 C,  113 D and  113 E are sectional illustrations taken along respective section lines and directions CXIIIA-CXIIIA, CXXIIIB-CXIIIB, CXIIIC-CXIIIC, CXIIID-CXIIID and CXIIIE-CXIIIE in  FIGS. 112A and 112B ; 
           [0129]      FIG. 114  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86J  in its operative orientation as it is being disengaged from the injection site; 
           [0130]      FIGS. 115A and 115B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 114 ; 
           [0131]      FIGS. 116A ,  116 B,  116 C,  116 D and  116 E are sectional illustrations taken along respective section lines and directions CXVIA-CXVIA, CXVIB-CXVIB, CXVIC-CXVIC, CXVID-CXVID and CXVIE-CXVIE in  FIGS. 115A and 115B ; 
           [0132]      FIG. 117  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86K  in a needle protected operative orientation; 
           [0133]      FIGS. 118A and 118B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 117 ; 
           [0134]      FIGS. 119A ,  119 B,  119 C,  119 D and  119 E are sectional illustrations taken along respective section lines and directions CXIXA-CXIXA, CXIXB-CXIXB, CXIXC-CXIXC, CXIXD-CXIXD and CXIXE-CXIXE in  FIGS. 118A and 118B ; 
           [0135]      FIG. 120  is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86L  in a needle-shield push back misuse operative orientation; 
           [0136]      FIGS. 121A and 121B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 120 ; and 
           [0137]      FIGS. 122A ,  122 B,  122 C,  122 D and  122 E are sectional illustrations taken along respective section lines and directions CXXIIA-CXXIIA, CXXIIB-CXXIIB, CXXIIC-CXXIIC, CXXIID-CXXIID and CXXIIE-CXXIIE in  FIGS. 121A and 121B . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0138]    Reference is now made to  FIGS. 1-26 , which illustrate the constituent elements of an automatic injection device constructed and operative in accordance with a preferred embodiment of the present invention. 
         [0139]    As seen with particular clarity in  FIG. 1 , the automatic injection device comprises a drug vial  10 , including a body portion  12 , a neck portion  14  and an elastomeric seal (not shown). The term “vial” is used throughout to describe any suitable container. The drug vial  10  is seated in a drug vial adaptor  20  having a septum  22  associated therewith. A needle guard element  30 , which is positioned by a compression spring  32  within a forward end of a forward housing  40 , is operative to engage, at a front end thereof, the drug vial adaptor  20 . 
         [0140]    A syringe  46 , including a rear flange  47  and having a hypodermic needle  48  integrally formed therewith, is operatively engaged by a plunger  49 . The term “syringe” is used throughout to refer to a container having an elongate bore along which a plunger and piston may travel. Syringe  46  and plunger  49  are preferably located within the forward housing  40 . Syringe  46  may be a conventional syringe, such as a commercially available syringe sold under the catalog designation BD-Hypak™ or may be any other suitable syringe or cartridge. 
         [0141]    Plunger  49  selectably engages a selectable driving assembly  50 , which includes a selectable driving element  51  and a pair of elastomeric motion damping elements  52  and  54 . Selectable driving assembly  50  is preferably at least partially seated within a rear housing  60 , forward of a main compression spring  62 , also seated within rear housing  60 . The main compression spring  62  provides selectable forward displacement to the selectable driving assembly  50 . Selectable operation of plunger  49  by selectable driving assembly  50  causes the plunger  49  to inject liquid contents of syringe  46  through hypodermic needle  48 . 
         [0142]    The rear housing  60  has associated therewith an actuation button  70 , operative to selectably actuate operation of selectable driving assembly  50 . Within rear housing  60  are seated a rear end element  80 , operative to seal the rear end of the rear housing  60 , and a plunger locking element  90 , cooperative with rear end element  80  and operative to lock the plunger  49  when liquid contents of the syringe  46  should not be injected through needle  48 . A locking rod  98  is operative to selectably engage the plunger locking element  90  thereby unlocking the plunger  49 . 
         [0143]    Reference is now made to  FIG. 2 , which is a simplified pictorial illustration of drug vial adaptor  20  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 3A and 3B , which are respective top and side view simplified planar illustrations of the drug vial adaptor of  FIG. 2 , and to  FIGS. 4A and 4B , which are sectional illustrations thereof taken along respective section lines and directions IVA-IVA and IVB-IVB in  FIGS. 3A and 3B . 
         [0144]    As seen in  FIGS. 2-4B , the drug vial adaptor  20  includes a generally circular cylindrical forward facing sleeve  200 , which is configured to generally enclose drug vial  10  ( FIG. 1 ) and is sized such as to render it difficult, if not impossible, to remove drug vial  10  from sleeve  200 , following full insertion of the drug vial  10  into the sleeve  200 . Sleeve  200  is preferably formed with a pair of oppositely placed windows  202  to enable a user to view the contents of the vial  10  following insertion thereof into sleeve  200 . 
         [0145]    It is seen that drug vial adaptor  20  is preferably side-to-side symmetric about a longitudinal axis  203 . 
         [0146]    Integrally formed with sleeve  200  is a generally rectangular cylindrical rearward facing sleeve  204  having first and second curved side walls  206  and  208  and first and second curved edge walls  210  and  212 . Hinged finger engagement portions  214  and  216  are integrally formed with edge walls  210  and  212  respectively. Side walls  206  and  208  are formed with respective rearward facing cut outs  218  and  220 . 
         [0147]    Hinged finger engagement portions  214  and  216  each include a generally planar portion  222  having an outwardly curved forward end  224 , defining a finger engagement surface  226 , and raised side edges  228  extending along both sides of portion  222 . An inwardly facing retaining protrusion  230  is located on an inwardly facing surface of a rearward end  232  of generally planar portion  222 . A pair of integrally formed side hinges  234  supports planar portion  222  in an elongate cut out  236  formed in each of edge walls  210  and  212 . 
         [0148]    The forward facing sleeve  200  includes a forward-most portion  240  having a first inner diameter and, rearward thereof, an intermediate portion  242  having a second inner diameter, less than the first inner diameter. A shoulder  244  is defined between portions  240  and  242 . Intermediate portion  242  is defined by a bulkhead  246  having defined at its center a hollow spike  248  which extends forwardly nearly to shoulder  244 . In use, spike  248  punctures the elastomeric seal of drug vial  10  ( FIG. 1 ), thereby to enable fluid communication between the interior of drug vial  10  and the interior of syringe  46  ( FIG. 1 ), via apertures  250  formed at a forward end of spike  248 . This takes place only after the vial adaptor  20  moves rearwardly along axis  203 , enabling fluid communication between the interior of syringe  46  and apertures  250 . 
         [0149]    Preferably, a plurality of centering and retaining ribs  252  are provided along an interior facing surface  254  of intermediate portion  242 . Ribs  252  preferably include a forwardly located interiorly facing protrusion  256  for engaging neck portion  14  of drug vial  10  ( FIG. 1 ). 
         [0150]    Extending rearwardly from bulkhead  246  into the interior of rearward facing sleeve  204  is a generally cylindrical fluid passageway defining lumen  258  which defines, at a rearward end thereof, a septum receiving recess  260  in which septum  22  is located. 
         [0151]    Preferably, a plurality of guiding ribs  262  are provided along interior facing surfaces  264  of side walls  206  and  208  and edge walls  210  and  212 . Additionally, a plurality of positioning ribs  266  extend rearwardly from bulkhead  246  along surfaces  264  of side walls  206  and  208 . 
         [0152]    Reference is now made to  FIG. 5 , which is a simplified pictorial illustration of needle guard element  30  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 6A and 6B , which are respective top and side view simplified planar illustrations of the needle guard element of  FIG. 5 , and to  FIGS. 7A and 7B , which are sectional illustrations thereof taken along respective section lines and directions VIIA-VIIA and VIIB-VIIB in  FIGS. 6A and 6B . 
         [0153]    As will be described hereinbelow in detail, needle guard element  30  includes a pair of restriction elements, which prevent actuation of the device when a user presses actuation button  70  ( FIG. 1 ) when the device is not pressed against the user&#39;s body. At a forward part of the needle guard element there is provided a cylindrical portion having a front end including a generally circular bore, through which the needle passes during injection of the drug. Following injection, the cylindrical portion is displaced forwardly relative to the needle, thereby covering the needle and preventing inadvertent needle pricks. 
         [0154]    As seen in  FIGS. 5-7B , the needle guard element  30  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration including a generally tubular portion  310 , having a forward facing body engaging surface  312  including pairs of concentrically located ribbed circumferential forward facing ring portions  314  and  316 . A rearward facing internal surface  317 , facing opposite from body engaging surface  312 , forms a spring-seat for spring  32  ( FIG. 1 ) in cooperation with rearward extensions  318  of ring portions  316  which assist in locating the spring  32  on surface  317 . 
         [0155]    Needle guard element  30  includes a pair of symmetric mounting arms  319  having rearwardmost ends  320 , arranged symmetrically about a longitudinal axis  321 , which, when the automatic injection device is assembled, is coaxial with the longitudinal axis  203  of drug vial adaptor  20  ( FIGS. 2-4B ). Mounting arms  319  are symmetric upon rotation about axis  321  and extend parallel thereto along and rearwardly of tubular portion  310 . Each of arms  319  is formed with a rectangular window  322 . 
         [0156]    Each of symmetric mounting arms  319  is formed with a forward portion  325  having formed therein an elongated slot  326 , which extends rearwardly of generally tubular portion  310  to a somewhat curved stop surface  328 . Stop surface  328  is disposed adjacent a forward edge of rectangular window  322 . A widened arm portion  330 , having an interiorly facing surface  331 , is formed on each of arms  319 . The widened arm portion  330  extends rearwardly along generally tubular portion  310  to a location rearwardly of rectangular window  322  and terminates in an inclined surface  332  adjacent a shoulder  333 . 
         [0157]    Extending further rearwardly from a location slightly forwardly of inclined surface  332 , is an intermediate arm portion  334 , having an outer surface which is disposed slightly radially outwardly with respect to longitudinal axis  321  as compared with forward portion  325 . At a rearward end  336  of intermediate arm portion  334 , the thickness of intermediate arm portion  334  is reduced, and arm  319  continues rearwardly at an outwardly inclined portion  338 . Outwardly inclined portion  338  is followed by rearwardmost end  320  of arm  319 , which has an inwardly facing generally trapezoidal protrusion  340 . As will be described hereinbelow, generally trapezoidal protrusion  340  serves as a restriction element, which prevents actuation of the device when a user presses actuation button  70  ( FIG. 1 ) when the device is not pressed against the user&#39;s body. 
         [0158]    Reference is now made to  FIG. 8 , which is a simplified pictorial illustration of forward housing  40  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 9A ,  9 B and  9 C, which are respective top, side and front view simplified planar illustrations of the forward housing of  FIG. 8 , and to  FIGS. 10A ,  10 B and  10 C, which are sectional illustrations taken along respective section lines and directions XA-XA, XB-XB and XC-XC in  FIGS. 9A and 9B . 
         [0159]    As will be described hereinbelow in detail, the forward housing  40  includes, at a forward portion thereof, two pairs of recesses  401 , adapted to receive the retaining protrusions  230  of the finger engagement portions  214  and  216  of the drug vial adaptor ( FIGS. 2-4B ). At a rear end of the forward housing  40  is a cutout portion  403  adapted to accommodate the actuation button  70  ( FIG. 1 ). As seen with particular clarity in  FIGS. 8 and 9C , the forward housing  40  includes a longitudinal recess or channel  404  which is adapted to accommodate the locking rod  98  ( FIG. 1 ). 
         [0160]    As seen in  FIGS. 8-10C , the forward housing  40  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration arranged along a longitudinal axis  405 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  203  ( FIGS. 2-4B ) and  321  ( FIGS. 5-7B ). Forward housing  40  includes a generally tubular rear portion  410 , having an open back and formed with a pair of top-to-bottom symmetric snap fit engagement sockets  412  which receive protrusions of the rear housing  60  ( FIG. 1 ) during factory assembly of the automatic injection device. 
         [0161]    Forward of tubular rear portion  410  and rearwardly of the recesses  401  are formed a pair of top-to-bottom symmetric windows  414 , which allow the syringe  46  ( FIG. 1 ) and drug content thereof to be viewed when the automatic injection device is assembled, during use thereof and otherwise. A pair of outer side surfaces  416  of forward housing  40  have corresponding inner side surfaces  421 , each of which defines a plurality of longitudinally extending ribs  422 ,  424 ,  426  and  428  which are used to slidably guide the needle guard element  30  ( FIGS. 5-7B ) during axial movement thereof. 
         [0162]    Inner facing protrusions  430  define a rearward facing spring seat  431  for spring  32  ( FIG. 1 ). Inner facing protrusions  430  are also operative to slidably support syringe  46  ( FIG. 1 ) and to slidably guide actuation arms of selectable driving assembly  50  ( FIG. 1 ). 
         [0163]    Inner top and bottom surfaces  432  and  434  define respective pairs of ribs  436  and  438  which are operative to slidably rotationally orient the syringe  46  ( FIG. 1 ) about axis  405  during axial movement of the syringe  46 . As best seen in  FIG. 10A , inner facing protrusions  430  define, at rearward facing portions thereof, protrusions  460  and  462  which form a stop for flange  47  ( FIG. 1 ), thus limiting the forward movement of the syringe  46  ( FIG. 1 ). 
         [0164]    Inner side surface  421  extends forwardly to an inwardly extending shoulder  463  from which extends an inner surface  464  which extends to a forward edge  465  of forward housing  40 . Shoulder  463  defines a stop which limits the forward movement of needle guard element  30  ( FIGS. 5-7B ) relative to forward housing  40 . 
         [0165]    As seen in  FIG. 1 , plunger  49  includes a threaded protrusion  470 , which threadably engages a corresponding threaded socket (not shown) formed in a rear surface of a resilient piston  471  which sealingly engages the interior of syringe  46 . Rearwardly of threaded protrusion  470  is a generally circular cylindrical portion  472  having a first cross sectional radius, followed by a relatively short circular cylindrical portion  474  having a second cross sectional radius greater than the first radius and defining a rearward facing shoulder  475 . 
         [0166]    Rearward of portion  474  is a third generally circular cylindrical portion  476  having a third cross sectional radius, generally equal to the first radius. Rearwardly of portion  476  is formed a toothed portion  477 , each tooth  478  thereof having a generally transverse forwardly facing portion  480  and a slanted rearwardly facing portion  482 . The particular shape of the teeth of toothed portion  477  enables rearward movement of the plunger  49  at any time, and requires a specific configuration of the device in order to enable forward movement of the plunger  49 . 
         [0167]    Plunger  49  is preferably symmetrically disposed about a longitudinal axis  484 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  203  ( FIGS. 2-4B ),  321  ( FIGS. 5-7B ) and  405  ( FIGS. 8-10C ). 
         [0168]    Reference is now made to  FIG. 11 , which is a simplified pictorial illustration of selectable driving assembly  50  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 12A and 12B , which are respective top and side view simplified planar illustrations of the selectable driving assembly of  FIG. 11 , and to  FIGS. 13A and 13B , which are sectional illustrations taken along respective section lines and directions XIIIA-XIIIA and XIIIB-XIIIB in  FIGS. 12A and 12B . 
         [0169]    The selectable driving assembly  50  includes selectable driving element  51  and elastomeric motion damping elements  52  and  54 . Selectable driving element  51  includes a rearward facing generally cylindrical portion  500  and a pair of longitudinal arms  502 . At a forward end  504  of each of the longitudinal arms  502  there is provided a first hinged finger  506  having formed thereon a pair of inwardly facing protrusions  508  and  510 . The inwardly facing protrusions  508  and  510  are adapted to engage the flange  47  of syringe  46  ( FIG. 1 ) to retain it in position during the stages shown in  FIGS. 27A-27E  and to control its forward movement during actuation of the device. Opposite protrusions  508  and  510 , on an outer facing surface of first hinged finger  506 , are formed a pair of outwardly facing generally trapezoidal protrusions  512  and  514 . It is seen that protrusion  512  extends outwardly to a greater degree than does protrusion  514 . 
         [0170]    Rearwardly of first hinged finger  506  on each of longitudinal arms  502  is a second hinged finger  516 , having an inwardly facing protrusion  518 , which is adapted to rearwardly displace the syringe  46  ( FIG. 1 ) following injection, when the needle guard element  30  ( FIGS. 5-7B ) is rearwardly displaced. 
         [0171]    Generally alongside and parallel to second hinged fingers  516  there are formed third hinged fingers  526 , each including an inwardly facing slanted protrusion  528 , operative to forwardly displace the plunger  49  ( FIG. 1 ) during injection, and a pair of outwardly facing protrusions  530  and  532 , which are operative to inwardly bend the third hinged fingers  526  during actuation and which engage the needle-guard element  30  ( FIGS. 5-7B ) and are operative to displace it forwardly as soon as the device disengages the user&#39;s body. 
         [0172]    The cylindrical portion  500  of the selectable driving assembly  50  includes protrusions  540  on opposite sides thereof, which are adapted to maintain the selectable driving assembly  50  in place when the device is in its storage position, by abutting against the actuation button  70  ( FIG. 1 ). The cylindrical portion  500  also has seated therein motion damping elements  52  and  54  which engage an internal surface of the rear housing  60  ( FIG. 1 ), and thus are operative to slow the forward movement of the selectable driving assembly, thereby slowing the forward movement of the syringe  46  ( FIG. 1 ) and plunger  49  ( FIG. 1 ) during injection. 
         [0173]    As seen in  FIGS. 11-13B , the selectable driving element  51  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration including generally cylindrical portion  500 , which has an open back. Longitudinal arms  502  are preferably symmetric actuation arms and extend forwardly of cylindrical portion  500  parallel to a longitudinal axis  560 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  203  ( FIGS. 2-4B ),  321  ( FIGS. 5-7B ),  405  ( FIGS. 8-10C ) and  484  ( FIG. 1 ). Arms  502  are symmetric upon rotation about axis  560 , and each has a generally curved cross section. 
         [0174]    An interior generally cylindrical surface  570  of cylindrical portion  500  terminates at a forward end of cylindrical portion  500  at a shoulder  572 , forwardly of which is an opening  574  through which extends plunger  49  ( FIG. 1 ). Shoulder  572  defines a spring seat for spring  62  ( FIG. 1 ). 
         [0175]    Reference is now made to  FIG. 14 , which is a simplified pictorial illustration of rear housing  60 , which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 15A ,  15 B and  15 C, which are respective top, side and rear view simplified planar illustrations of the rear housing of  FIG. 14 , and to  FIGS. 16A ,  16 B and  16 C, which are sectional illustrations taken along respective section lines and directions XVIA-XVIA, XVIB-XVIB and XVIC-XVIC in  FIGS. 15A and 15B . 
         [0176]    As seen in  FIGS. 14-16C , the rear housing  60  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration arranged about a longitudinal axis  603 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  203  ( FIGS. 2-4B ),  321  ( FIGS. 5-7B ),  405  ( FIGS. 8-10C ),  484  ( FIG. 1) and 560  ( FIGS. 11-13B ). The rear housing  60  includes a tube  610 , which includes a forward portion  612  having an interiorly facing surface  614  including four generally equally spaced, longitudinally extending, guiding ribs  616 . Also formed on interiorly facing surface  614  are a pair of interiorly facing protrusions  617  whose width tapers in a forwardly facing direction to a point, thus defining a generally triangular engagement surface for elastomeric motion damping elements  52  and  54  ( FIG. 1 ). Disposed adjacent the wide end of each of protrusions  617  are an inclined recess  618  and a cylindrical recess  619 , which serve to guide elastomeric motion damping elements  52  and  54  upstream of their engagement with protrusions  617 . 
         [0177]    Formed on a pair of generally equally spaced exteriorly facing surfaces  620  and  621  of tube  610  are respective generally rectangular outwardly protruding frames  622  and  624 . Further protrusions  626  and  628  are located interiorly of frames  622  and  624  respectively and centered adjacent rearward ends thereof. Protrusions  626  and  628  are accommodated in snap fit engagement sockets  412  of the forward housing  40  ( FIGS. 8-10C ) during factory assembly of the device, and thereby maintain the connection of the rear housing  60  to the forward housing  40 . 
         [0178]    Formed in tube  610  adjacent a rearward end thereof are a pair of side cutouts  630  each having an undercut forward edge  632 . Disposed forwardly of each of edges  632  is a generally rectangular outwardly facing protrusion  634 . 
         [0179]    Integrally formed with tube  610  and partially overlapping a rearward portion thereof is a generally cylindrical rearward housing surface portion  640  including first and second generally rectangular side surface portions  642 , intermediate surface portions  644 , a top surface portion  646  and a bottom surface portion  648 . At its rearward end, tube  610  is formed with a transverse curved recess  650 . Rearwardly of recess  650  is a generally cylindrical portion  660 . 
         [0180]    Disposed rearwardly of portion  660  is a wall  662  which connects tube  610  to surface  646 . Adjacent surfaces  644  and  646 , the wall  662  is generally perpendicular to tube  610  and to surfaces  644  and  646 . Adjacent surface  648 , the wall includes a perpendicular portion  664  and a tapered portion  666 . An opening  668  in wall  662  communicates with a volume disposed between cylindrical portion  660  and surface  646 . 
         [0181]    Four elongate tracks  670 , disposed alongside curved recess  650  between tube  610  and surfaces  642 , preferably each having a generally U-shaped cross section, define a pair of guiding tracks for actuation button  70  ( FIG. 1 ). A pair of rear end element retaining portions  672  are located rearwardly of tracks  670  for engagement with rear end element  80 . 
         [0182]    Between each pair of tracks  670  there is disposed a flexible biasing finger  673  for engagement with actuation button  70 . 
         [0183]    Extending between each of forwardly disposed tracks  670  and a corresponding rectangular side surface  642  are a pair of transverse portions  674  and  675  which guide a corresponding arm  319  ( FIGS. 5-7B ) of needle guard element  30 . 
         [0184]    As seen with particular clarity in  FIG. 15C , there are provided longitudinally extending bores  676  and  677  for accommodating locking rod  98  ( FIG. 1 ) 
         [0185]    Reference is now made to  FIGS. 17A and 17B , which are respective front and back view simplified pictorial illustrations of actuation button  70  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 18A and 18B , which are respective top and side view simplified planar illustrations of the actuation button of  FIGS. 17A and 17B , and to  FIGS. 19A and 19B , which are sectional illustrations taken along respective section lines and directions XIXA-XIXA and XIXB-XIXB in  FIGS. 18A and 18B . 
         [0186]    The actuation button  70  has the general configuration of a side-to-side symmetric arch and includes a central portion  700  having a top finger engagement surface  702 , a pair of generally rectangular legs  704 , and a bottom surface  726 . Each of legs  704  includes first and second generally trapezoidal forwardly directed protrusions  708  and  710  and first and second generally trapezoid rearwardly directed protrusions  712  and  714 , which are adapted to be seated in correspondingly configured tracks  670  ( FIGS. 14-16C ) of the rear housing  60 . Intermediate the forwardly directed protrusions  708  and  710  and rearwardly directed protrusions  712  and  714 , each leg  704  includes first and second outwardly facing recesses  716  and  718 , which are adapted to engage the flexible biasing fingers  673  ( FIGS. 14-16C ) of the rear housing  60  and thereby maintain the actuation button  70  in either its storage state or its activated state. 
         [0187]    Adjacent the forwardly directed protrusions  708  and  710  and rearwardly directed protrusions  712  and  714  on each leg  704  there is provided a generally L-shaped transverse outwardly facing protrusion  720  with respect to which the generally trapezoidal protrusions  340  ( FIGS. 5-7B ) of the needle guard element  30  are oriented prior to actuation of the device, so as to prevent premature actuation of the device. The L-shaped transverse outwardly facing protrusions  720  additionally prevent the inward displacement of the actuation button  70  when the device is not pressed against the user&#39;s body and the needle guard element  30  ( FIGS. 5-7B ) is not rearwardly displaced. 
         [0188]    Each of the legs  704  additionally includes a rearward facing surface  722 , against which protrusion  540  ( FIG. 11-13B ) of the selectable driving assembly  50  abuts prior to actuation of the device. 
         [0189]    During inward displacement of the actuation button  70  and resulting actuation of the device, the plunger locking element  90  ( FIG. 1 ) abuts against bottom surface  726  of the central portion  700 , generally underlying the top finger engagement surface  702 . 
         [0190]    Reference is now made to  FIG. 20 , which is a simplified pictorial illustration of plunger locking element  90  which forms-part of the automatic injection device of  FIG. 1 , to  FIGS. 21A ,  21 B,  21 C and  21 D, which are respective rear, top, front and side view simplified planar illustrations of the plunger locking element of  FIG. 20 , and to  FIGS. 22A and 22B , which are sectional illustrations taken along respective section lines and directions XXIIA-XXIIA and XXIIB-XXIIB in  FIG. 21B . 
         [0191]    The plunger locking element  90  is preferably an integrally formed element, preferably injection molded of plastic and includes an upright back portion  800  having, at a central bottom region thereof, a plunger engaging protrusion  802  having a curved bottom facing edge surface  804  which engages the teeth  478  of toothed portion  477  ( FIG. 1 ) of the plunger  49  and thus prevents the plunger  49  from moving forward. An actuation button engagement surface  806  is provided on a forwardly extending protrusion  808  of the top portion of the plunger locking element  90 . The actuation button engagement surface  806  is engaged by the actuation button  70  ( FIGS. 17A-19B ) and is rotated thereby about an axis  810 , extending perpendicular to axis  603  of rear housing  60  ( FIGS. 14-16B ), during actuation of the device, thereby releasing the locking of the plunger  49  ( FIG. 1 ). 
         [0192]    A pair of forwardly facing protrusions  812 , each having a curved forward end  814 , define axis  810  about which the plunger locking element  90  rotates during actuation of the device. These protrusions are seated in corresponding hemispherical recesses of the rear end element  80  ( FIG. 1 ). A resilient leg  820  extends downwardly  from back portion  800 , generally alongside one of the forwardly facing protrusions  812  and constantly urges the plunger locking element  90  to rotate about axis  810  to a configuration in which the plunger  49  ( FIG. 1 ) is locked. When the plunger locking element  90  is rotated about axis  810 , the resilient leg  820  abuts against the rear end element  80  ( FIG. 1 ) and the plunger  49  is released. 
         [0193]    A pair of downward facing protrusions  822 , each having a generally planar forwardly facing surface  824 , are formed on either side of the back portion  800  of the plunger locking element  90 . When the drug vial adaptor  20  ( FIGS. 2-4B ) is connected to the forward housing  40  ( FIGS. 8-10C ), drug vial adaptor  20  rearwardly pushes a forward portion of the locking rod  98  ( FIG. 1 ) which extends forwardly out of the forward housing  40 , thereby rearwardly displacing the locking rod  98 . When the locking rod  98  is rearwardly displaced, a rearward portion thereof abuts against protrusions  822  and causes rotation of the plunger locking element  90 , about axis  810 , thereby releasing the plunger  49  ( FIG. 1 ). 
         [0194]    Reference is now made to  FIG. 23 , which is a simplified pictorial illustration of rear end element  80  which forms part of the automatic injection device of  FIG. 1 , to  FIGS. 24A and 24B , which are respective top and side view simplified planar illustrations of the rear end element of  FIG. 23 , and to  FIGS. 25A ,  25 B and  25 C, which are sectional illustrations taken along respective section lines and directions XXVA-XXVA, XXVB-XXVB and XXVC-XXVC in  FIGS. 24A and 24B . 
         [0195]    The rear end element  80  includes a generally cylindrical forward portion  900  terminating rearwardly in a generally planar rearward portion  902 . Cylindrical forward portion  900  and rearward portion  902  together define a rearward spring seat for spring  62  ( FIG. 1 ). The cylindrical portion  900  includes a central bore  903  which is adapted to accommodate the plunger  49  ( FIG. 1 ). Extending forwardly from planar rearward portion  902  alongside cylindrical portion  900  are a pair of resilient fingers  904  each including an outwardly facing hook type protrusion  906 . The resilient fingers  904  are adapted to engage corresponding rear end element retaining portions  672  in rear housing  60  ( FIGS. 14-16C ) and to maintain secure engagement of the rear end element  80  thereto. Generally planar rearward portion  902  defines a cut out  908  which accommodates forwardly extending protrusion  808  of the plunger locking element  90 . 
         [0196]    Adjacent resilient fingers  904  are a pair of partially semicircular recesses  910 , which define the location of axis  810  about which the plunger locking element  90  rotates. Rearward portion  902  also includes a forwardly facing protrusion  912 , which is adapted to engage resilient leg  820  ( FIGS. 20-22B ) of the plunger locking element  90 . 
         [0197]    Reference is now made to  FIG. 26 , which is a simplified pictorial illustration of locking rod  98  which forms part of the automatic injection device of  FIG. 1 . 
         [0198]    The locking rod  98  includes a first longitudinally extending portion  950 , terminating rearwardly at a rearward facing transverse portion  952  which, in turn terminates at a second longitudinally extending portion  954  which is generally parallel to the first longitudinally extending portion  950 . 
         [0199]    Reference is now made to  FIGS. 27A ,  27 B,  27 C,  27 D,  27 E,  27 F,  27 G,  27 H,  27 I,  27 J and  27 K which are simplified pictorial illustrations of various stages of typical use of the automatic injection device of  FIG. 1 . 
         [0200]      FIG. 27A  illustrates insertion of vial  10  into vial adaptor  20 , which forms part of the automatic injection device of  FIG. 1 .  FIG. 27B  shows the vial  10  fully inserted into vial adaptor  20 , it being appreciated that removal of the vial  10  from vial adaptor  20  following full insertion thereof is very difficult or impossible. It is further appreciated that insertion of vial  10  into vial adaptor  20  causes vial adaptor  20  to be displaced in a rearward direction indicated by an arrow  960  in  FIG. 27A , with respect to the remainder of the automatic injection device of  FIG. 1 . 
         [0201]      FIG. 27C  shows liquid from vial  10  being drawn into syringe  46 . This is achieved by a user, holding the automatic injection device of  FIG. 1  in a generally vertical orientation as shown, pulling the plunger  49  in a direction indicated by an arrow  962 , downward in the sense of  FIG. 27C  and rearward in the sense of  FIG. 1 . During this procedure, the user sees the amount of liquid in the syringe  46  via window  414  in forward housing  40 . It is appreciated that at this stage, the plunger  49  can be displaced by the user in a direction opposite to that indicated by arrow  962 . 
         [0202]      FIG. 27D  illustrates removal of the vial adaptor  20 , containing vial  10 , from the forward housing  40 , by first pressing inwardly on finger engagement portions  214  and  216  as indicated by arrows  964  and  966  respectively and then pulling vial adaptor  20  in a direction indicated by an arrow  968 . It is appreciated that at this stage, here termed a ready to inject stage, following removal of the vial adaptor  20  from the forward housing  40 , the plunger  49  cannot be displaced by the user in a direction opposite to that indicated by arrow  962  ( FIG. 27C ). 
         [0203]    Turning now to  FIG. 27E , it is seen that a user is employing the automatic injection device to inject a liquid into his body. As illustrated in enlargement  970 , it is seen that by pressing the automatic injection device against his body, in a direction indicated by an arrow  972 , the user causes needle guard element  30  to be pushed in a direction indicated by an arrow  974 , rearwardly with respect to forward housing  40 . This rearward motion unlocks actuation button  70 , such that when the user presses on the actuation button  70 , as indicated by an arrow  976  in enlargement  978 , the actuation button  70  is operative to initiate injection. 
         [0204]    As seen in  FIG. 27F , during such injection, responsive to user operation of the actuation button  70 , the syringe  46  moves forwardly in a direction indicated by an arrow  980  causing the needle  48  of syringe  46  to penetrate the user&#39;s body and subsequently inject liquid into the user&#39;s body, as shown in  FIG. 27G . It is noted that as the injection of the liquid proceeds, the plunger  49  moves forwardly relative to syringe  46  and to the remainder of the injection device, as indicated by an arrow  982  in  FIG. 27G .  FIG. 27H  shows completion of the injection of the liquid, with the plunger  49  being in a fully forward orientation relative to the remainder of the injection device. 
         [0205]    As seen in  FIG. 27I , following completion of the injection of the liquid, the user retracts the injection device slightly from his body, as indicated by an arrow  984 , causing corresponding retraction of needle  48  from his body and corresponding extension of needle guard element  30  forwardly with respect to the forward housing  40 , as indicated by an arrow  986 .  FIG. 27J  shows the injection device fully disengaged from the user&#39;s body and the needle guard  30  in a fully extended orientation relative to the forward housing  40 , fully covering the needle  48  and generally preventing finger engagement with the needle  48 . 
         [0206]      FIG. 27K  shows that retraction of the needle guard element  30  is such that even if a user pushes the needle guard element  30  rearwardly as indicated by an arrow  988 , the needle guard element  30  causes the needle  48  to be retracted, in a direction indicated by an arrow  990 , to the same extent, such that engagement of a user&#39;s finger with the tip of needle  48  is prevented. 
         [0207]    Reference is now made to  FIG. 28 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27A  in a pre-use and storage operative orientation, to  FIGS. 29A and 29B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 28 , and to  FIGS. 30A ,  30 B,  30 C,  30 D and  30 E, which are sectional illustrations taken along respective section lines and directions XXXA-XXXA, XXXB-XXXB, XXXC-XXXC, XXXD-XXXD and XXXE-XXXE in  FIGS. 29A and 29B . 
         [0208]    As seen in FIGS.  27 A and  28 - 30 E, the vial adaptor  20  is maintained in engagement with the forward housing  40  by engagement of inwardly facing retaining protrusions  230  with forward recesses  401  and therefore does not rearwardly displace the locking rod  98 . 
         [0209]      FIGS. 30A and 30C  show that the protrusion  720  of the actuation button  70  is oriented, with respect to the generally trapezoidal protrusions  340  of the needle guard element  30 , so as to prevent depression of the actuation button  70 . Additionally, abutment of protrusion  720  against generally trapezoidal protrusions  340  prevents forward displacement of needle guard element  30  relative to forward housing  40  against the urging of spring  32 . 
         [0210]    Furthermore, the flexible biasing fingers  673  of the rear housing  60  engage corresponding second outwardly facing recesses  718  of the actuation button  70 , and maintain it in the storage orientation shown in  FIG. 28 . 
         [0211]      FIG. 30D  shows the locking rod  98  abutting against the downward facing protrusions  822  of the plunger locking element  90 . The enlarged portion of  FIG. 30B  shows the plunger engaging protrusion  802  of the plunger locking element  90  in a locking orientation with respect to plunger  49 .  FIG. 30E  shows the resilient leg  820  of the plunger locking element  90  engaging the forwardly facing protrusion  912  of the rear end element  80 . 
         [0212]    As seen in  FIGS. 28-30E , in a pre-use operative orientation of the automatic injection device which is suitable for storage, the rear housing  60  is joined to the forward housing  40  by snap fit engagement of protrusions  626  and  628  of rear housing  60  in the snap fit engagement sockets  412  formed in the forward housing  40 . 
         [0213]    As seen with particular clarity in the enlarged portion of  FIG. 30A , the selectable driving assembly  50  is retained in its axial position by engagement of rearward facing surface  722  with protrusion  540  of the selectable driving assembly  50 . In this arrangement, spring  62  is in a relatively compressed state and is held in that state by the selectable driving assembly  50 . 
         [0214]    The syringe  46  is retained in a retracted orientation by engagement of flange  47  thereof with inwardly facing protrusions  508  and  510  formed in respective first hinged fingers  506  of each of symmetric actuation arms  502  of selectable driving assembly  50  ( FIGS. 11-13B ). 
         [0215]    It is appreciated that when the automatic injection device is in its orientation shown in  FIGS. 28-30E , needle  48  does not pierce septum  22 . 
         [0216]    Reference is now made to  FIG. 31 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27B  in a vial connection orientation, to  FIGS. 32A and 32B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 31 , and to  FIGS. 33A ,  33 B,  33 C,  33 D and  33 E, which are sectional illustrations taken along respective section lines and directions XXXIIIA-XXXIIIA, XXXIIIB-XXXIIIB, XXXIIIC-XXXIIIC, XXXIIID-XXXIIID and XXXIIIE-XXXIIIE in  FIGS. 32A and 32B . 
         [0217]    As seen in  FIG. 27B  and  FIGS. 31-33E , the vial  10  is fully inserted in the vial adaptor  20 , causing the vial adaptor  20  to be displaced fully rearwardly relative to the forward housing  40 . This displacement causes corresponding rearward displacement of the locking rod  98  relative to, inter alia, the forward housing  40 . The vial adaptor  20  is maintained in place by engagement of inwardly facing retaining protrusions  230  with rearward recesses  401 . The interior of vial  10  is in fluid flow communication with the interior of syringe  46  via needle  48  which extends through septum  22 . 
         [0218]      FIG. 33D  shows the locking rod  98  rearwardly pushing the downward facing protrusions  822  of the plunger locking element  90  thereby causing rotation of the plunger locking element  90  about axis  810 . The enlarged portion of  FIG. 33B  shows the rotation of the plunger engaging protrusion  802  of the plunger locking element  90  about axis  810  such that it does not engage the plunger  49 .  FIG. 33E  shows a slight bend in the resilient leg  820  of the plunger locking element  90  resulting from rotation thereof about axis  810 . 
         [0219]    Reference is now made to  FIG. 34 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27C  in a vial pumping orientation, to  FIGS. 35A and 35B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 34 , and to  FIGS. 36A ,  36 B,  36 C,  36 D and  36 E, which are sectional illustrations taken along respective section lines and directions XXXVIA-XXXVIA, XXXVIB-XXXVIB, XXXVIC-XXXVIC, XXXVID-XXXVID and XXXVIE-XXXVIE in  FIGS. 35A and 35B . 
         [0220]    As seen in FIGS.  27 C and  34 - 36 E, the plunger  49  is rearwardly displaced, thereby drawing liquid from the interior of vial  10  into the syringe  46  via needle  48 . The enlarged portion of  FIG. 36B  clearly illustrates that the plunger engaging protrusion  802  of the plunger locking element  90  is located above one of the teeth  478  of the toothed portion  477  of the plunger  49 . 
         [0221]    Reference is now made to  FIG. 37 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27D  in a drug vial adaptor removal orientation, to  FIGS. 38A and 38B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 37 , and to  FIGS. 39A ,  39 B,  39 C,  39 D and  39 E, which are sectional illustrations taken along respective section lines and directions XXXIXA-XXXIXA, XXXIXB-XXXIXB, XXXIXC-XXXIXC, XXXIXD-XXXIXD and XXXIXE-XXXIXE in  FIGS. 38A and 38B . 
         [0222]    As seen in FIGS.  27 D and  37 - 39 E, the vial adaptor  20  is removed from the forward housing  40  by a user pressing the finger engagement surfaces  226  of vial adaptor  20  which disengages inwardly facing retaining protrusions  230  from rearward recesses  401 . The disengagement of the vial adaptor  20  from the remainder of the injection device enables the locking rod  98  to return to its orientation shown in  FIGS. 28-30E . The plunger locking element  90  rotates about axis  810  back to its orientation shown in  FIGS. 28-30E  under the urging of the resilient leg  820  and thereby forwardly displaces the locking rod  98 . 
         [0223]    As seen in  FIG. 39B , the plunger locking element  90 , once returned to its orientation shown in  FIGS. 28-30E , locks plunger  49  by engagement of plunger engaging protrusion  802  with teeth  478  of toothed portion  477  of the plunger  49 , thereby preventing forward displacement of the plunger  49  by a user.  FIG. 39E  shows that the resilient leg  820  of the plunger locking element  90  returns to its orientation shown in  FIGS. 28-30E  in which it is not bent and is located adjacent the forwardly facing protrusion  912  of the rear end element  80 . 
         [0224]    Reference is now made to  FIG. 40 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27E  in an actuated operative orientation, to  FIGS. 41A and 41B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 40 , and to  FIGS. 42A ,  42 B,  42 C,  42 D and  42 E, which are sectional illustrations taken along respective section lines and directions XLIIA-XLIIA, XLIIB-XLIIB, XLIIC-XLIIC, XLIID-XLIID and XLIIE-XLIIE in  FIGS. 41A and 41B . 
         [0225]    As seen in FIGS.  27 E and  40 - 42 E, the user pushes the automatic injection device against his body, thereby rearwardly displacing the needle guard element  30  relative to the forward housing  40 . As seen with particular clarity in  FIGS. 42A-42D , the rearward displacement of the needle guard element  30  results in rearward displacement of the generally trapezoidal protrusions  340  thereof, which no longer are oriented with respect to the L-shaped transverse outwardly facing protrusions  720  of the arms of the actuation button  70  so as to prevent actuation. Thus, the actuation button  70  is free to be pressed by a user. Until the actuation button  70  is actually pressed by the user, the flexible biasing fingers  673  of the rear housing  60  still engage corresponding second outwardly facing recesses  718  of the legs  704  of the actuation button  70 , maintaining it in the “ready to inject” stage. 
         [0226]    As seen in  FIG. 42A , due to engagement of the needle guard element  30  with an injection site on a body, the resulting rearward displacement of needle guard element  30  with respect to the remainder of the automatic injection device compresses spring  32 . The rearward motion of the needle guard element  30  is limited by engagement of the forward facing edge of forward portion  612  of rear housing  60  with shoulders  333  of arms  319  of the needle guard element  30 . 
         [0227]    In this orientation of the needle guard element  30 , pressing of button  70  actuates the automatic injection device. 
         [0228]    Reference is now made to  FIG. 43 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27F  in a needle penetration, pre-drug delivery operative orientation, to  FIGS. 44A and 44B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 43 , and to  FIGS. 45A ,  45 B,  45 C,  45 D and  45 E, which are sectional illustrations taken along respective section lines and directions XLVA-XLVA, XLVB-XLVB, XLVC-XLVC, XLVD-XLVD and XLVE-XLVE in  FIGS. 44A and 44B . 
         [0229]    As seen in FIGS.  27 F and  43 - 45 E, the user actuates the automatic injection device by inwardly displacing the actuation button  70 . The inward displacement of the actuation button  70  displaces the actuation button engagement surface  806  of forwardly extending protrusion  808  of the plunger locking element  90 , thereby rotating the plunger locking element  90  about axis  810  and releasing the plunger  49 . Additionally, the protrusions  540  of selectable driving assembly  50  no longer abut against the rearward facing surfaces  722  of the legs  704  of the actuation button  70 , and the selectable driving assembly  50  is forwardly displaced under the force of spring  62 . 
         [0230]      FIG. 45C  shows the inward displacement of the actuation button  70 , which results in the flexible biasing fingers  673  of the rear housing  60  engaging the first outwardly facing recesses  716  of the legs  704  of the actuation button  70 , and maintaining actuation button  70  in an actuated orientation.  FIGS. 45B ,  45 D and  45 E show the rotation of the plunger locking element  90 , which is caused by the inward displacement of the actuation button  70 . 
         [0231]      FIGS. 45A and 45B  illustrate the forward displacement of the selectable driving assembly  50 , accompanied by forward displacement of the syringe  46 , which results in needle penetration. As seen in the first enlarged portion of  FIG. 45A , when the needle  48  has fully penetrated the body, the forward displacement of the syringe  46  is stopped by engagement of flange  47  with protrusions  460  and  462  of the forward housing  40  ( FIG. 45B ). The selectable driving assembly  50  continues its forward displacement, thereby outwardly bending the first hinged fingers  506  of the selectable driving assembly  50  into a space formed by rectangular window  322 , and releasing fingers  506  from engagement with the flange  47  of the syringe  46 . 
         [0232]    The third hinged fingers  526  of the selectable driving assembly  50  are inwardly displaced by engagement of protrusions  530  and  532  with undercut forward edge  632 , and the inwardly facing slanted protrusions  528  of selectable driving assembly  50  are located adjacent rearwardly facing shoulder  475  of cylindrical portion  474  of the plunger  49 . The enlarged portion of  FIG. 45B  shows the rotation of the plunger engaging protrusion  802  of the plunger locking element  90  such that it no longer prevents the forward movement of plunger  49 .  FIG. 45E  shows a slight bend in the resilient leg  820  of the plunger locking element  90 . 
         [0233]    During needle penetration, elastomeric motion damping elements  52  and  54  initially engage inclined recesses  618  and then engage interiorly facing protrusions  617 . As will be described hereinbelow, drug delivery follows needle penetration. 
         [0234]    Reference is now made to  FIG. 46 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27G  in a drug delivery operative orientation, to  FIGS. 47A and 47B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 46 , and to  FIGS. 48A ,  48 B,  48 C,  48 D and  48 E, which are sectional illustrations taken along respective section lines and directions XLVIIIA-XLVIIIA, XLVIIIB-XLVIIIB, XLVIIIC-XLVIIIC, XLVIIID-XLVIIID and XLVIIIE-XLVIIIE in  FIGS. 47A and 47B . 
         [0235]    As seen in FIGS.  27 G and  46 - 48 E, the selectable driving assembly  50  continues its forward displacement, such that the inwardly facing slanted protrusions  528  of the selectable driving assembly  50  engage shoulder  475  of the plunger  49  and forwardly displace the plunger  49 . The forward displacement of the plunger  49 , which is illustrated with particular clarity in  FIG. 48A , results in injection of a drug into the body. 
         [0236]    Reference is now made to  FIG. 49 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27H  in an immediate post-drug delivery operative orientation, to  FIGS. 50A and 50B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 49 , and to  FIGS. 51A ,  51 B,  51 C,  51 D and  51 E, which are sectional illustrations taken along respective section lines and directions LIA-LIA, LIB-LIB, LIC-LIC, LID-LID and LIE-LIE in  FIGS. 50A and 50B . 
         [0237]    As seen in FIGS.  27 H and  49 - 51 E, the plunger  49  is fully forwardly displaced and has reached the forward end of the syringe  46 . As seen with particular clarity in the enlarged portion of  FIG. 51A , the outwardly facing protrusions  532  of the third hinged fingers  526  of the selectable driving assembly  50 , which slid along interiorly facing surface  614  of the rear housing  60 , now slide along interiorly facing surface  331  of the mounting arms  319  of the needle guard element  30 , while the inwardly facing slanted protrusions  528  of the third hinged fingers  526  of the selectable driving assembly  50  continue to engage shoulder  475  of the plunger  49 . It is appreciated that forward displacement of both plunger  49  and selectable driving assembly  50  is stopped at this stage. Drug delivery is complete. 
         [0238]    Reference is now made to;  FIG. 52 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27I  in its operative orientation as it is being disengaged from the injection site, to  FIGS. 53A and 53B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 52 , and to  FIGS. 54A ,  54 B,  54 C,  54 D and  54 E, which are sectional illustrations taken along respective section lines and directions LIVA-LIVA, LIVB-LIVB, LIVC-LIVC, LIVD-LIVD and LIVE-LIVE in  FIGS. 53A and 53B . 
         [0239]    As seen in FIGS.  27 I and  52 - 54 E, the user is beginning to disengage the automatic injection device from his body, thereby enabling the needle guard element  30  to be forwardly displaced under the force of spring  32 . As seen with particular clarity in the enlarged portion of  FIG. 54A , during the forward displacement of the needle guard element  30 , the outwardly facing protrusions  532  of the third hinged fingers  526  of the selectable driving assembly  50  move along the interiorly facing surface  331  of the mounting arms  319  of the needle guard element  30 , until they pass shoulder  333  in the mounting arms  319  of the needle guard element  30 . The third hinged fingers  526  of the selectable driving assembly  50  snap outwardly once the shoulder  333  of the needle guard element  30  has been sufficiently forwardly displaced, thereby causing the disengagement of the inwardly facing slanted protrusions  528  of the third hinged fingers  526  of the selectable driving assembly  50  from the shoulder  475  of the plunger  49 . At this stage, the selectable driving assembly  50  does not engage the plunger  49 , and selectable driving assembly  50  can continue to be forwardly displaced under the force of spring  62 , thereby forwardly displacing needle guard element  30 . 
         [0240]    Reference is now made to  FIG. 55 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27J  in a needle protected operative orientation, to  FIGS. 56A and 56B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 55 , and to  FIGS. 57A ,  57 B,  57 C,  57 D and  57 E, which are sectional illustrations taken along respective section lines and directions LVIIA-LVIIA, LVIIB-LVIIB, LVIIC-LVIIC, LVIID-LVIID and LVIIE-LVIIE in  FIGS. 56A and 56B . 
         [0241]    As seen in FIGS.  27 J and  55 - 57 E, the selectable driving assembly  50  continues to be forwardly displaced under the force of spring  62 , thereby forwardly displacing the needle guard element  30 . The forward displacement of the needle guard element  30  is terminated by engagement of stop surfaces  328  of the needle guard element  30  with corresponding inwardly extending shoulders  463  of forward housing  40 , at which stage the needle  48  is fully enclosed by the needle guard element  30  and is locked with respect thereto. As seen with particular clarity in the enlarged portion of  FIG. 57A , the forward displacement of the selectable driving assembly  50  results in the second hinged fingers  516  thereof being positioned forwardly of the flange  47  of the syringe  46 . This produces the positive locking of the needle  48  with respect to the needle guard element  30 . It is noted that the third hinged fingers  526  cannot be bent inwardly at this stage due to engagement of inwardly facing slanted protrusions  528  with cylindrical portion  474 . 
         [0242]    Reference is now made to  FIG. 58 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 1 and 27K  in a needle-shield push back misuse operative orientation, to  FIGS. 59A and 59B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 58 , and to  FIGS. 60A ;  60 B,  60 C,  60 D and  60 E, which are sectional illustrations taken along respective section lines and directions LXA-LXA, LXB-LXB, LXC-LXC, LXD-LXD and LXE-LXE in  FIGS. 59A and 59B . 
         [0243]    As seen in FIGS.  27 K and  58 - 60 E, when a user misuses the device and rearwardly displaces the needle guard element  30 , the rearward displacement of the needle guard element  30  results in rearward displacement of the selectable driving assembly  50 . Shoulders  333  of arms  319  of the needle guard  30  push against protrusion  532  of the selectable driving assembly  50 . Selectable driving assembly  50  is therefore forced to undergo rearward displacement. Due to this rearward displacement of the selectable driving assembly  50 , the second hinged fingers  516  thereof engage the forward facing surface of the flange  47  of the syringe  46 . Continued rearward displacement of the selectable driving assembly  50  results in rearward displacement of the syringe  46  and needle  48  together with the selectable driving assembly  50  and the needle guard element  30 , thereby ensuring that the needle  48  is not exposed at any stage following injection. 
         [0244]    Reference is now made to  FIGS. 61-85C , which illustrate the constituent elements of an automatic injection device constructed and operative in accordance with another preferred embodiment of the present invention. 
         [0245]    As seen with particular clarity in  FIG. 61 , the automatic injection device comprises a drug vial  1010 , including a body portion  1012 , a neck portion  1014  and an elastomeric seal (not shown). The drug vial  1010  is seated in a drug vial adaptor  1020  having a septum  1022  associated therewith. A needle guard element  1030 , which is positioned by a compression spring  1032  within a forward end of a forward housing  1040 , is operative to engage, at a front end thereof, the drug vial adaptor  1020 . 
         [0246]    A syringe  1046 , including a rear flange  1047  and having a hypodermic needle  1048  integrally formed therewith, is operatively engaged by a plunger  1049 . Syringe  1046  and plunger  1049  are preferably located within the forward housing  1040 . Syringe  1046  may be a conventional syringe, such as a commercially available syringe sold under the catalog designation BD-Hypak™ or may be any other suitable syringe or cartridge. 
         [0247]    Plunger  1049  selectably engages a selectable driving assembly  1050 , which includes a selectable driving element  1051  and a pair of elastomeric motion damping elements  1052  and  1054 . Selectable driving assembly  1050  is preferably at least partially seated within a rear housing  1060 , forward of a main compression spring  1062 , also seated within rear housing  1060 . The main compression spring  1062  provides selectable forward displacement to the selectable driving assembly  1050 . Selectable operation of plunger  1049  by selectable driving assembly  1050  causes the plunger  1049  to inject liquid contents of syringe  1046  through hypodermic needle  1048 . 
         [0248]    The rear housing  1060  has associated therewith an actuation button  1070 , operative to selectably actuate operation of selectable driving assembly  1050 . Within rear housing  1060  are seated a rear end element  1080 , operative to seal the rear end of the rear housing  1060 , and a plunger locking element  1090 , cooperative with rear end element  1080  and operative to lock the plunger  1049  when liquid contents of the syringe  1046  should not be injected through needle  1048 . 
         [0249]    Reference is now made to  FIG. 62 , which is a simplified pictorial illustration of drug vial adaptor  1020  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 63A and 63B , which are respective top and side view simplified planar illustrations of the drug vial adaptor of  FIG. 62 , and to  FIGS. 64A and 64B , which are sectional illustrations taken along respective section lines and directions LXIVA-LXIVA and LXIVB-LXIVB in  FIGS. 63A and 63B . 
         [0250]    As seen in  FIGS. 62-64B , the drug vial adaptor  1020  includes a generally circular cylindrical forward facing sleeve  1200 , which is configured to generally enclose drug vial  1010  ( FIG. 61 ) and is sized such as to render it difficult, if not impossible, to remove drug vial  1010  from sleeve  1200 , following full insertion of the drug vial  1010  into the sleeve  1200 . Sleeve  1200  is preferably formed with a pair of oppositely placed windows  1202  to enable a user to view the contents of the vial  1010  following insertion thereof into sleeve  1200 . 
         [0251]    It is seen that drug vial adaptor  1020  is preferably side-to-side symmetric about a longitudinal axis  1203 . 
         [0252]    Integrally formed with sleeve  1200  is a generally rectangular cylindrical rearward facing sleeve  1204  having first and second curved side walls  1206  and  1208  and first and second curved edge walls  1210  and  1212 . Hinged finger engagement portions  1214  and  1216  are integrally formed with edge walls  1210  and  1212  respectively. Side walls  1206  and  1208  are formed with respective rearward facing cut outs  1218  and  1220 . 
         [0253]    Hinged finger engagement portions  1214  and  1216  each include a generally planar portion  1222  having an outwardly curved forward end  1224 , defining a finger engagement surface  1226 , and raised side edges  1228  extending along both sides of portion  1222 . An inwardly facing retaining protrusion  1230  is located on an inwardly facing surface of a rearward end  1232  of generally planar portion  1222 . A pair of integrally formed side hinges  1234  supports planar portion  1222  in an elongate cut out  1236  formed in each of edge walls  1210  and  1212 . 
         [0254]    The forward facing sleeve  1200  includes a forward-most portion  1240  having a first inner diameter and rearward thereof an intermediate portion  1242  having a second inner diameter, less than the first inner diameter. A shoulder  1244  is defined between portions  1240  and  1242 . Intermediate portion  1242  is defined by a bulkhead  1246  having defined at its center a hollow spike  1248  which extends forwardly nearly to shoulder  1244 . In use, spike  1248  punctures the elastomeric seal of drug vial  1010  ( FIG. 61 ), thereby to enable fluid communication between the interior of drug vial  1010  and the interior of syringe  1046  ( FIG. 61 ), via apertures  1250  formed at a forward end of spike  1248 . This takes place only after the vial adaptor  1020  moves rearwardly along axis  1203 , enabling fluid communication between the interior of syringe  1046  and apertures  1250 . 
         [0255]    Preferably, a plurality of centering and retaining ribs  1252  are provided along an interior facing surface  1254  of intermediate portion  1242 . Ribs  1252  preferably include a forwardly located interiorly facing protrusion  1256  for engaging neck portion  1014  of drug vial  1010  ( FIG. 61 ). 
         [0256]    Extending rearwardly from bulkhead  1246  into the interior of rearward facing sleeve  1204  is a generally cylindrical fluid passageway defining lumen  1258  which defines at a rearward end thereof a septum receiving recess  1260  in which septum  1022  is located. 
         [0257]    Preferably, a plurality of guiding ribs  1262  are provided along interior facing surfaces  1264  of side walls  1206  and  1208  and edge walls  1210  and  1212 . Additionally, a plurality of positioning ribs  1266  extend rearwardly from bulkhead  1246  along surfaces  1264  of side walls  1206  and  1208 . A pair of positioning protrusions  1268  extend rearwardly from bulkhead  1246  and are adapted to push the needle guard element  1030  ( FIG. 61 ) rearwardly during pumping of the vial  1010 , which in turn disengages the plunger locking element  1090  ( FIG. 61 ) from the plunger  1049  ( FIG. 61 ) to enable forward movement of plunger  1049 . 
         [0258]    Reference is now made to  FIG. 65 , which is a simplified pictorial illustration of needle guard element  1030  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 66A and 66B , which are respective top and side view simplified planar illustrations of the needle guard element of  FIG. 65 , and to  FIGS. 67A and 67B , which are sectional illustrations taken along respective section lines and directions LXVIIA-LXVIIA and LXVIIB-LXVIIB in  FIGS. 66A and 66B . 
         [0259]    As will be described hereinbelow in detail, needle guard element  1030  includes a pair of restriction elements, which prevent actuation of the device when a user presses actuation button  1070  ( FIG. 61 ) when the device is not pressed against the user&#39;s body. At a forward part of the needle guard element  1030  there is provided a cylindrical portion having a front end including a generally circular bore, through which the needle passes during injection of the drug. Following injection, the cylindrical portion is displaced forwardly relative to the needle, thereby covering the needle and preventing inadvertent needle pricks. 
         [0260]    As seen in  FIGS. 65-67B , the needle guard element  1030  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration including a generally tubular portion  1310 , having a forward facing body engaging surface  1312  including pairs of concentrically located ribbed circumferential forward facing ring portions  1314  and  1316 . A rearward facing internal surface  1317 , facing opposite from body engaging surface  1312 , forms a spring-seat for spring  1032  ( FIG. 61 ) in cooperation with rearward extensions  1318  of ring portions  1316  which assist in locating the spring  1032  on surface  1317 . 
         [0261]    Needle guard element  1030  includes a pair of symmetric mounting arms  1319  having rearwardmost ends  1320 , arranged symmetrically about a longitudinal axis  1321 , which, when the automatic injection device is assembled, is coaxial with the longitudinal axis  1203  of drug vial adaptor  1020  ( FIGS. 62-64B ). Mounting arms  1319  are symmetric upon rotation about axis  1321  and extend parallel thereto along and rearwardly of tubular portion  1310 . Each of arms  1319  is formed with a rectangular window  1322 . 
         [0262]    Each of symmetric mounting arms  1319  is formed with a forward portion  1325  having formed therein an elongated slot  1326 , which extends rearwardly of generally tubular portion  1310  to a somewhat curved stop surface  1328 . Stop surface  1328  is disposed adjacent a forward edge of rectangular window  1322 . A widened arm portion  1330 , having an interiorly facing surface  1331 , is formed on each of arms  1319 . The widened arm portion  1330  extends rearwardly along generally tubular portion  1310  to a location rearwardly of rectangular window  1322  and terminates in an inclined surface  1332  adjacent a shoulder  1333 . 
         [0263]    Extending further rearwardly from a location slightly forwardly of inclined surface  1332 , is an intermediate arm portion  1334 , having an outer surface which is disposed slightly radially outwardly with respect to longitudinal axis  1321  as compared with forward portion  1325 . At a rearward end  1336  of intermediate arm portion  1334 , the thickness of intermediate arm portion  1334  is reduced, and arm  1319  continues rearwardly at an outwardly inclined portion  1338 . Outwardly inclined portion  1338  is followed by rearwardmost end  1320  of arm  1319 , which has an inwardly facing generally trapezoidal protrusion  1340 . As will be described hereinbelow, generally trapezoidal protrusion  1340  serves as a restriction element, which prevents actuation of the device when a user presses actuation button  1070  ( FIG. 61 ) when the device is not pressed against the user&#39;s body. 
         [0264]    Each of rearward most ends  1320  of arms  1319  terminates in a generally T-shaped portion  1342 , including a pair of protrusions  1344  having an outwardly inclined surface  1346 . The protrusions  1344  are adapted to enable the release of the plunger  1049  ( FIG. 61 ) from its locked orientation when the drug vial adaptor  1020  ( FIG. 62-64B ) is axially positioned with respect to the forward housing  1040 , as shown in  FIG. 86B , as will be explained with further detail hereinbelow. 
         [0265]    Reference is now made to  FIG. 68 , which is a simplified pictorial illustration of forward housing  1040  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 69A and 69B , which are respective top and side view simplified planar illustrations of the forward housing of  FIG. 68 , and to  FIGS. 70A ,  70 B and  70 C, which are sectional illustrations taken along respective section lines and directions LXXA-LXXA, LXXB-LXXB and LXXC-LXXC in  FIGS. 69A and 69B . 
         [0266]    As will be described hereinbelow in detail, the forward housing  1040  includes at a forward portion thereof, two pairs of recesses  1401 , adapted to receive the retaining protrusions  1230  of the finger engagement portions  1214  and  1216  of the drug vial adaptor  1020  ( FIGS. 62-64B ). At a rear end of the forward housing  1040  is a cutout portion  1403  adapted to accommodate the actuation button  1070  ( FIG. 61 ). 
         [0267]    As seen in  FIGS. 68-70C , the forward housing  1040  preferably is an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration arranged along a longitudinal axis  1405 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  1203  ( FIGS. 62-64B ) and  1321  ( FIGS. 65-67B ). Forward housing  1040  includes a generally tubular rear portion  1410 , having an open back and formed with a pair of top-to-bottom symmetric snap fit engagement sockets  1412  which receive protrusions of the rear housing  1060  ( FIG. 61 ) during factory assembly of the automatic injection device. 
         [0268]    Forward of tubular rear portion  1410  and rearwardly of the recesses  1401  are formed a pair of top-bottom symmetric windows  1414 , which allow the syringe and drug content thereof to be viewed when the automatic injection device is assembled, during use thereof and otherwise. A pair of outer side surfaces  1416  of forward housing  1040  have corresponding inner side surfaces  1421  each of which defines a plurality of longitudinally extending ribs  1422 ,  1424 ,  1426  and  1428  which are used to slidably guide the needle guard element  1030  ( FIGS. 65-67B ) during axial movement thereof. 
         [0269]    Inner facing protrusions  1430  define a rearward facing spring seat  1431  for spring  1032  ( FIG. 61 ). Inner facing protrusions  1430  are also operative to slidably support syringe  1046  ( FIG. 61 ) and to slidably guide actuation arms of selectable driving assembly  1050  ( FIG. 61 ). 
         [0270]    Inner top and bottom surfaces  1432  and  1434  define respective pairs of ribs  1436  and  1438  which are operative to slidably rotationally orient the syringe  1046  ( FIG. 61 ) about axis  1405  during axial movement of the syringe  1046 . As best seen in  FIG. 70A , inner facing protrusions  1430  define at rearward facing portions thereof protrusions  1460  and  1462  which form a stop for flange  1047  ( FIG. 61 ), thus limiting the forward movement of the syringe  1046  ( FIG. 61 ). 
         [0271]    Inner side surface  1421  extends forwardly to an inwardly extending shoulder  1463  from which extends an inner surface  1464  which extends to a forward edge  1465  of forward housing  1040 . Shoulder  1463  defines a stop which limits the forward movement of needle guard element  1030  ( FIGS. 65-67B ) relative to forward housing  1040 . 
         [0272]    As seen in  FIG. 61 , plunger  1049  includes a threaded protrusion  1470 , which threadably engages a corresponding threaded socket (not shown) formed in a rear surface of a resilient piston  1471  which sealingly engages the interior of syringe  1046 . Rearwardly of threaded protrusion  1470  is a generally circular cylindrical portion  1472  having a first cross sectional radius, followed by a relatively short circular cylindrical portion  1474  having a second cross sectional radius greater than the first radius and defining a rearward facing shoulder  1475 . 
         [0273]    Rearward of portion  1474  is a third generally circular cylindrical portion  1476  having a third cross sectional radius, generally equal to the first radius. Rearwardly of portion  1476  is formed a toothed portion  1477 , each tooth  1478  thereof having a generally transverse forwardly facing portion  1480  and a slanted rearwardly facing portion  1482 . The particular shape of the teeth of toothed portion  1477  enables rearward movement of the plunger  1049  at any time, and requires a specific configuration of the device in order to enable forward movement of the plunger  1049 . 
         [0274]    Plunger  1049  is preferably symmetrically disposed about a longitudinal axis  1484 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  1203  ( FIGS. 62-64B ),  1321  ( FIGS. 65-67B ) and  1405  ( FIGS. 68-70C ). 
         [0275]    Reference is now made to  FIG. 71 , which is a simplified pictorial illustration of selectable driving assembly  1050  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 72A and 72B , which are respective top and side view simplified planar illustrations of the selectable driving assembly of  FIG. 71 , and to  FIGS. 73A and 73B , which are sectional illustrations taken along respective section lines and directions LXXIIIA-LXXIIIA and LXXIIIB-LXXIIIB in  FIGS. 72A and 72B . 
         [0276]    The selectable driving assembly  1050  includes selectable driving element  1051  and elastomeric motion damping elements  1052  and  1054 . Selectable driving element  1051  includes a rearward facing generally cylindrical portion  1500  and a pair of longitudinal arms  1502 . At a forward end  1504  of each of the longitudinal arms  1502  there is provided a first hinged finger  1506  having formed thereon a pair of inwardly facing protrusions  1508  and  1510 . The inwardly facing protrusions  1508  and  1510  are adapted to engage the flange  1047  of syringe  1046  ( FIG. 61 ) to retain it in position during the stages shown in  FIGS. 86A-86F  and to control its forward movement during actuation of the device. Opposite protrusions  1508  and  1510 , on an outer facing surface of first hinged finger  1506 , are formed a pair of outwardly facing generally trapezoidal protrusions  1512  and  1514 . It is seen that protrusion  1512  extends outwardly to a greater degree than does protrusion  1514 . 
         [0277]    Rearwardly of first hinged finger  1506  on each of longitudinal arms  1502  is a second hinged finger  1516 , having an inwardly facing protrusion  1518 , which is adapted to rearwardly displace the syringe  1046  ( FIG. 61 ) following injection, when the needle guard element  1030  ( FIGS. 65-67B ) is rearwardly displaced. 
         [0278]    Generally alongside and parallel to second hinged fingers  1516  there are formed third hinged fingers  1526 , each including an inwardly facing slanted protrusion  1528  operative to forwardly displace the plunger  1049  ( FIG. 61 ) during injection, and a pair of outwardly facing protrusions  1530  and  1532 , which are operative to inwardly bend the third hinged fingers  1526  during actuation and which engage the needle guard element  1030  ( FIGS. 65-67B ) and are operative to displace it forwardly as soon as the device disengages the user&#39;s body. 
         [0279]    The cylindrical portion  1500  of the selectable driving element  1051  includes protrusions  1540  on opposite sides thereof, which are adapted to maintain the selectable driving assembly  1050  in place when the device is in its storage position, by abutting against the actuation button  1070  ( FIG. 61 ). The cylindrical portion  1500  also has seated therein motion damping elements  1052  and  1054  which engage an internal surface of the rear housing  1060  ( FIG. 61 ), and thus are operative to slow the forward movement of the selectable driving assembly  1050 , thereby slowing the forward movement of the syringe  1046  ( FIG. 61 ) and plunger  1049  ( FIG. 61 ) during injection. 
         [0280]    As seen in  FIGS. 71-73B , the selectable driving element  1051  preferably is an integrally formed, element, preferably injection molded of plastic and preferably has a generally cylindrical configuration including generally cylindrical portion  1500 , which has an open back. Longitudinal arms  1502  are preferably symmetric actuation arms and extend forwardly of cylindrical portion  1500  parallel to a longitudinal axis  1560 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  1203  ( FIGS. 62-64B ),  1321  ( FIGS. 65-67B ),  1405  ( FIGS. 68-70C ) and  1484  ( FIG. 61 ). Arms  1502  are symmetric upon rotation about axis  1560 , and each has a generally curved cross section. 
         [0281]    An interior generally cylindrical surface  1570  of cylindrical portion  1500  terminates at a forward end of cylindrical portion  1500  at a shoulder  1572 , forwardly of which is an opening  1574  through which extends plunger  1049  ( FIG. 61 ). Shoulder  1572  defines a spring seat for spring  1062  ( FIG. 61 ). 
         [0282]    Reference is now made to  FIG. 74 , which is a simplified pictorial illustration of rear housing  1060  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 75A and 75B , which are respective top and side view simplified planar illustrations of the rear housing of  FIG. 74 , and to  FIGS. 76A ,  76 B and  76 C, which are sectional illustrations taken along respective section lines and directions LXXVIA-LXXVIA, LXXVIB-LXXVIB and LXXVIC-LXXVIC in  FIGS. 75A and 75B . 
         [0283]    As seen in  FIGS. 74-76C , the rear housing  1060  is preferably an integrally formed element, preferably injection molded of plastic and preferably has a generally cylindrical configuration arranged about a longitudinal axis  1603 , which, when the automatic injection device is assembled, is coaxial with longitudinal axes  1203  ( FIGS. 62-64B ),  1321  ( FIGS. 65-67B ),  1405  ( FIGS. 68-70C ),  1484  ( FIG. 61) and 1560  ( FIGS. 71-73B ). The rear housing  1060  includes a tube  1610 , which includes a forward portion  1612  having an interiorly facing surface  1614  including four generally equally spaced, longitudinally extending, guiding ribs  1616 . Also formed on interiorly facing surface  1614  are a pair of interiorly facing protrusions  1617  whose width tapers in a forwardly facing direction to a point, thus defining a generally triangular engagement surface for elastomeric motion damping elements  1052  and  1054  ( FIG. 61 ). Disposed adjacent the wide end of each of protrusions  1617  are an inclined recess  1618  and a cylindrical recess  1619 , which serve to guide elastomeric motion damping elements  1052  and  1054  upstream of their engagement with protrusions  1617 . 
         [0284]    Formed on a pair of generally equally spaced exteriorly facing surfaces  1620  and  1621  of tube  1610  are respective generally rectangular outwardly protruding frames  1622  and  1624 . Further protrusions  1626  and  1628  are located interiorly of frames  1622  and  1624  respectively and centered adjacent rearward ends thereof. Protrusions  1626  and  1628  are accommodated in snap fit engagement sockets  1412  of the forward housing  1040  ( FIGS. 68-70C ) during factory assembly of the device, and thereby maintain the connection between the rear housing  1060  and the forward housing  1040 . Formed in tube  1610  adjacent a rearward end thereof are a pair of side cutouts  1630  each having an undercut forward edge  1632 . Disposed forwardly of each of edges  1632  is a generally rectangular outwardly facing protrusion  1634 . 
         [0285]    Integrally formed with tube  1610  and partially overlapping a rearward portion thereof is a generally cylindrical rearward housing surface portion  1640  including first and second generally rectangular side surface portions  1642 , intermediate surface portions  1644 , a top surface portion  1646  and a bottom surface portion  1648 . At its rearward end, tube  1610  is formed with a transverse curved recess  1650 . Rearwardly of recess  1650  is a generally cylindrical portion  1660 . 
         [0286]    Disposed rearwardly of portion  1660  is a wall  1662  which connects tube  1610  to surface  1646 . Adjacent surfaces  1644  and  1646 , the wall  1662  is generally perpendicular to tube  1610  and to surfaces  1644  and  1646 . Adjacent surface  1648 , the wall includes a perpendicular portion  1664  and a tapered portion  1666 . An opening  1668  in wall  1662  communicates with a volume disposed between cylindrical portion  1660  and surface  1646 . 
         [0287]    Four elongate tracks  1670 , disposed alongside curved recess  1650  between tube  1610  and surfaces  1642 , preferably each having a generally U-shaped cross section, define a pair of guiding tracks for actuation button  1070  ( FIG. 61 ). A pair of rear end element retaining portions  1672  are located rearwardly of tracks  1670  for engagement with rear end element  1080  ( FIG. 61 ). 
         [0288]    Between each pair of tracks  1670  there is disposed a flexible biasing finger  1673  for engagement with actuation button  1070  ( FIG. 61 ). 
         [0289]    Extending between each of forwardly disposed tracks  1670  and a corresponding rectangular side surface  1642  are a pair of transverse portions  1674  and  1675  which guide a corresponding arm  1319  ( FIGS. 65-67B ) of needle guard element  1030 . 
         [0290]    Reference is now made to  FIGS. 77A and 77B , which are respective front and back view simplified-pictorial illustrations of actuation button  1070  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 78A and 78B , which are respective top and side view simplified planar illustrations of the actuation button of  FIGS. 77A and 77B , and to  FIGS. 79A and 79B , which are sectional illustrations taken along respective section lines and directions LXXIXA-LXXIXA and LXXIXB-LXXIXB in  FIGS. 78A and 78B . 
         [0291]    The actuation button  1070  has the general configuration of a side-to-side symmetric arch and includes a central portion  1700  having a top finger engagement surface  1702 , and a pair of generally rectangular legs  1704 . Each of legs  1704  includes first and second generally trapezoidal forwardly directed protrusions  1708  and  1710  and first and second generally trapezoid rearwardly directed protrusions  1712  and  1714 , which are adapted to be seated in correspondingly configured tracks  1670  ( FIGS. 74-76C ) of the rear housing  1060 . Intermediate the forwardly directed protrusions  1708  and  1710  and rearwardly directed protrusions  1712  and  1714 , each leg  1704  includes first and second outwardly facing recesses  1716  and  1718 , which are adapted to engage the flexible biasing fingers  1673  ( FIGS. 74-76C ) of the rear housing  1060  and thereby maintain the actuation button  1070  in either its storage state or its activated state. 
         [0292]    Adjacent the forwardly directed protrusions  1708  and  1710  and rearwardly directed protrusions  1712  and  1714  on each leg  1704  there is provided a generally L-shaped transverse outwardly facing protrusion  1720  with respect to which the generally trapezoidal protrusions  1340  ( FIGS. 65-67B ) of the needle guard element  1030  are oriented prior to actuation of the device, so as to prevent premature actuation of the device. The L-shaped transverse outwardly facing protrusions  1720  additionally prevent the downward displacement of the actuation button  1070  when the device is not pressed against the user&#39;s body and the needle guard element  1030  ( FIGS. 65-67B ) is not rearwardly displaced. 
         [0293]    Each of the legs  1704  additionally includes a rearward facing surface  1722 , against which protrusion  1540  ( FIG. 71-73B ) of the selectable driving assembly  1050  abuts prior to actuation of the device. 
         [0294]    During downward displacement of the actuation button  1070  and resulting actuation of the device, the plunger locking element  1090  ( FIG. 61 ) abuts against a bottom surface  1726  of the central portion  1700 , generally underlying the top finger engagement surface  1702 . 
         [0295]    Reference is now made to  FIG. 80 , which is a simplified pictorial illustration of plunger locking element  1090  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 81A ,  81 B,  81 C,  81 D and  81 E, which are respective top, left side, right side, bottom and front view simplified planar illustrations of the plunger locking element of  FIG. 80 , and to  FIGS. 82A and 82B , which are sectional illustrations taken along respective section lines and directions LXXXIIA-LXXXIIA and LXXXIIB-LXXXIIB in  FIG. 81A . 
         [0296]    The plunger locking element  1090  is preferably an integrally formed element, preferably injection molded of plastic and includes an upright back portion  1800  having at a central bottom region thereof a plunger engaging protrusion  1802  having a curved bottom facing edge surface  1804  which engages the teeth  1478  of toothed portion  1477  ( FIG. 61 ) of the plunger  1049  and thus prevents the plunger  1049  from moving forward. 
         [0297]    An actuation button engagement surface  1806  is provided on a forwardly extending protrusion  1808  of the top portion of the plunger locking element  1090 . The actuation button engagement surface  1806  is engaged by the actuation button  1070  ( FIGS. 77-79B ) and is rotated thereby about an axis  1810 , extending perpendicular to axis  1603  of rear housing  1060  ( FIGS. 74-76B ), during actuation of the device, thereby releasing the locking of the plunger  1049  ( FIG. 61 ). 
         [0298]    A pair of forwardly facing protrusions  1812 , each having a curved forward end  1814 , define axis  1810  about which the plunger locking element  1090  rotates during actuation of the device. These protrusions are adapted to be seated in corresponding hemispherical recesses in the rear end element  1080  ( FIG. 61 ). 
         [0299]    A resilient leg  1820  extends downwardly from back portion  1800 , generally alongside one of the forwardly facing protrusions  1812  and constantly urges the plunger locking element  1090  to rotate about axis  1810  to a configuration in which the plunger  1049  ( FIG. 61 ) is locked. When the plunger locking element  1090  is rotated about axis  1810 , the resilient leg  1820  abuts against a forward facing protrusion of the rear end element  1080  ( FIG. 61 ) and the plunger  1049  is released. 
         [0300]    A pair of downward facing protrusions  1822 , each having a slanted forwardly facing surface  1824 , a generally planar bottom surface  1826 , and a generally planar rearwardly facing surface  1828 , are formed on either of forwardly facing protrusions  1812  of the plunger locking element  1090 . During operation of the device, such as during the injection stage, generally T-shaped portions  1342  ( FIGS. 65-67B ) of needle guard element  1030  abut against slanted forwardly facing surfaces  1824  of protrusions  1822 , causing rotation of the plunger locking element  1090  about axis  1810 , and thereby releasing the plunger  1049  ( FIG. 61 ). 
         [0301]    Reference is now made to  FIG. 83 , which is a simplified pictorial illustration of rear end element  1080  which forms part of the automatic injection device of  FIG. 61 , to  FIGS. 84A and 84B , which are respective top and side view simplified planar illustrations of the rear end element of  FIG. 83 , and to  FIGS. 85A ,  85 B and  85 C, which are sectional illustrations taken along respective section lines and directions LXXXVA-LXXXVA, LXXXVB-LXXXVB and LXXXVC-LXXXVC in  FIGS. 84A and 84B . 
         [0302]    The rear end element  1080  includes a generally cylindrical forward portion  1900  terminating rearwardly in a generally planar rearward portion  1902 . Cylindrical forward portion  1900  and rearward portion  1902  together define a rearward spring seat for spring  1062  ( FIG. 61 ). The cylindrical portion  1900  includes a central bore  1903  which is adapted to accommodate the plunger  1049  ( FIG. 61 ). Extending forwardly from planar rearward portion  1902  alongside cylindrical portion  1900  are a pair of resilient fingers  1904  each including an outwardly facing hook type protrusion  1906 . The resilient fingers  1904  are adapted to engage corresponding rear end element retaining portions  1672  ( FIG. 74-76C ) in rear housing  1060  and to maintain secure engagement of the rear end element  1080  thereto. 
         [0303]    Generally planar rearward portion  1902  defines a cut out  1908  which is adapted to accommodate forwardly extending protrusion  1808  of the plunger locking element  1090  ( FIGS. 80-82E ). Adjacent resilient fingers  1904  are a pair of partially semicircular recesses  1910 , which define the location of axis  1810  about which the plunger locking element  1090  ( FIG. 61 ) rotates, and which accommodate curved forward ends  1814  of protrusions  1812  of plunger locking element  1090 . Rearward portion  1902  also includes a forwardly facing protrusion  1912  which is adapted to engage the resilient leg  1820  of plunger locking element  1090 . 
         [0304]    Reference is now made to  FIGS. 86A ,  86 B,  86 C,  86 D,  86 E,  86 F,  86 G,  86 H,  86 I,  86 J,  86 K and  86 L, which are simplified pictorial illustration of various stages of typical use of the automatic injection device of  FIG. 61 . 
         [0305]      FIG. 86A  illustrates insertion of vial  1010  into vial adaptor  1020 , which forms part of the automatic injection device of  FIG. 61 .  FIG. 86B  shows the vial  1010  fully inserted into vial adaptor  1020 , it being appreciated that removal of the vial  1010  from vial adaptor  1020  following full insertion thereof is very difficult or impossible. It is further appreciated that insertion of vial  1010  into vial adaptor  1020  causes vial adaptor  1020  to be displaced in a rearward direction indicated by an arrow  1960  in  FIG. 86A , with respect to the remainder of the automatic injection device of  FIG. 61 . 
         [0306]      FIG. 86C  shows liquid from vial  1010  being drawn into syringe  1046 . This is achieved by a user, holding the automatic injection device of  FIG. 61  in a generally vertical orientation as shown, pulling the plunger  1049  in a direction indicated by an arrow  1962 ; downward in the sense of  FIG. 86C  and rearward in the sense of  FIG. 61 . During this procedure, the user sees the amount of liquid in the syringe  1046  via windows  1414  in forward housing  1040 . It is appreciated that at this stage, the plunger  1049  can be displaced by the user in a direction opposite to that indicated by arrow  1962 . 
         [0307]      FIG. 86D  illustrates removal of the vial adaptor  1020 , containing vial  1010 , from the forward housing  1040 , by first pressing inwardly on finger engagement portions  1214  and  1216  as indicated by arrows  1964  and  1966  respectively and then pulling vial adaptor  1020  in a direction indicated by an arrow  1968 . It is appreciated that at this stage, here termed a ready to inject stage, following removal of the vial adaptor  1020  from the forward housing  1040 , the plunger  1049  cannot be displaced by the user in a direction opposite to that indicated by arrow  1962  ( FIG. 86C ). 
         [0308]    Turning now to  FIG. 86E , it is seen that a user is employing the automatic injection device to inject a liquid into his body. As illustrated in enlargement  1970 , it is seen that by pressing the automatic injection device against his body, in a direction indicated by an arrow  1972 , the user causes needle guard element  1030  to be pushed in a direction indicated by an arrow  1974 , rearwardly with respect to forward housing  1040 . This rearward motion unlocks actuation button  1070 , such that when the user presses on the actuation button  1070 , as indicated by an arrow  1976  in enlargement  1978 , the actuation button  1070  is operative to initiate injection. 
         [0309]    As seen in  FIG. 86F , if for any reason the user, prior to pressing the actuation button  1070 , removes the automatic injection device from pressed engagement with his body, as indicated by arrow  1980 , the needle guard element  1030  is forwardly displaced in the direction indicated by arrow  1982  and returns to its initial position as shown in  FIG. 86D . This forward displacement of the needle guard element  1030  re-locks the actuation button  1070 , such that even if the user were to press on the actuation button  1070  injection would not be initiated until the automatic injection device is again pressed against his body. At this stage, the user can proceed as described hereinabove with reference to  FIG. 86E . 
         [0310]      FIG. 86G  illustrates that, during injection, responsive to user operation of the actuation button  1070 , the syringe  1046  moves forwardly in a direction indicated by an arrow  1984  causing the needle  1048  of syringe  1046  to penetrate the user&#39;s body and subsequently inject liquid into the user&#39;s body, as shown in  FIG. 86H . It is noted that as the injection of the liquid proceeds, the plunger  1049  moves forwardly relative to syringe  1046  and to the remainder of the injection device, as indicated by an arrow  1986  in  FIG. 86H .  FIG. 86I  shows completion of the injection of the liquid, with the plunger  1049  being in a fully forward orientation relative to the remainder of the injection device. 
         [0311]    As seen in  FIG. 86J , following completion of the injection of the liquid, the user retracts the injection device slightly from his body, as indicated by an arrow  1988 , causing corresponding retraction of needle  1048  from his body and corresponding extension of needle guard element  1030  forwardly with respect to the forward housing  1040 , as indicated by an arrow  1990 .  FIG. 86K  shows the injection device fully disengaged from the user&#39;s body and the needle guard  1030  in a fully extended orientation relative to the forward housing  1040 , fully covering the needle  1048  and generally preventing finger engagement with the needle  1048 . 
         [0312]      FIG. 86L  shows that retraction of the needle guard element  1030  is such that even if a user pushes the needle guard element  1030  rearwardly as indicated by an arrow  1992 , the needle guard element  1030  causes the needle  1048  to be retracted, in a direction indicated by an arrow  1994 , to the same extent, such that engagement of a user&#39;s finger with the tip of needle  1048  is prevented. 
         [0313]    Reference is now made to  FIG. 87 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86A  in a pre-use operative orientation, to  FIGS. 88A and 88B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 87 , and to  FIGS. 89A ,  89 B,  89 C,  89 D and  89 E, which are sectional illustrations taken along respective section lines and directions LXXXIXA-LXXXIXA, LXXXIXB-LXXXIXB, LXXXIXC-LXXXIXC, LXXXIXD-LXXXIXD and LXXXIXE-LXXXIXE in  FIGS. 88A and 88B . 
         [0314]    As seen in FIGS.  86 A and  87 - 89 E, the vial adaptor  1020  is maintained in engagement with the forward housing  1040  by engagement of inwardly facing retaining protrusions  1230  with forward recesses  1401 . 
         [0315]      FIGS. 89A and 89C  show that the protrusion  1720  of the actuation button  1070 , is oriented with respect to the generally trapezoidal protrusions  1340  of the needle guard element  1030 , so as to prevent depression of the actuation button  1070 . Additionally, abutment of protrusion  1720  against generally trapezoidal protrusions  1340  prevents forward displacement of needle guard element  1030  relative to forward housing  1040  against the urging of spring  1032 . 
         [0316]    Furthermore, the flexible biasing fingers  1673  of the rear housing  1060  engage corresponding second outwardly facing recesses  1718  of the actuation button  1070 , and maintain it in the storage orientation shown in  FIG. 87 . 
         [0317]      FIG. 89D  shows the T-shaped protrusions  1342  of the needle guard element  1030  spaced from the slanted forwardly facing surfaces  1824  of the downward facing protrusions  1822  of the plunger locking element  1090 . 
         [0318]    The enlarged portion of  FIG. 89B  shows the plunger engaging protrusion  1802  of the plunger locking element  1090  in a locking orientation with respect to plunger  1049 .  FIG. 89E  shows the resilient leg  1820  of the plunger locking element  1090  engaging the forwardly facing protrusion  1912  of the rear end element  1080 . 
         [0319]    As seen in  FIGS. 87-89E , in a pre-use operative orientation of the automatic injection device which is suitable for storage, the rear housing  1060  is joined to the forward housing  1040  by snap fit engagement of protrusions  1626  and  1628  of rear housing  1060  in the snap fit engagement sockets  1412  formed in the forward housing  1040 . 
         [0320]    As seen with particular clarity in the enlarged portion of  FIG. 89A , the selectable driving assembly  1050  is retained in its axial position by engagement of rearward facing surface  1722  of the actuation button  1070  with protrusion  1540  of the selectable driving assembly  1050 . In this arrangement, spring  1062  is in a relatively compressed state and is held in that state by the selectable driving assembly  1050 . 
         [0321]    The syringe  1046  is retained in a retracted orientation by engagement of flange  1047  thereof with inwardly facing protrusions  1508  and  1510  formed in respective first hinged fingers  1506  of each of symmetric actuation arms  1502  of selectable driving assembly  1050 . 
         [0322]    It is appreciated that when the automatic injection device is in its orientation shown in  FIGS. 87-89E , needle  1048  does not pierce septum  1022 . 
         [0323]    Reference is now made to  FIG. 90 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86B  in a vial connection orientation, to  FIGS. 91A and 91B  are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 90 , and to  FIGS. 92A ,  92 B,  92 C,  92 D and  92 E, which are sectional illustrations taken along respective section lines and directions XCIIA-XCIIA, XCIIB-XCIIB, XCIIC-XCIIC, XCIID-XCIID and XCIIE-XCIIE in  FIGS. 91A and 91B . 
         [0324]    As seen in  FIG. 86B  and  FIGS. 90-92E , the vial  1010  is fully inserted in the vial adaptor  1020 , causing the vial adaptor  1020  to be displaced fully rearwardly relative to the forward housing  1040 . The vial adaptor  1020  is maintained in place by engagement of inwardly facing retaining protrusions  1230  with rearward recesses  1401 . The interior of vial  1010  is in fluid flow communication with the interior of syringe  1046  via needle  1048  which extends through septum  1022 . 
         [0325]    As seen in  FIG. 92A , the rearward displacement of vial adaptor  1020  results in engagement between positioning protrusions  1268  of the vial adaptor  1020  and the body engaging surface  1312  of the needle guard element, which causes the needle guard element  1030  to be rearwardly displaced relative to forward housing  1040 . 
         [0326]      FIG. 92D  shows that the rearward displacement of the needle guard element  1030 , causes the T-shaped protrusions  1342  thereof to push the downward facing protrusions  1822  of the plunger locking element  1090  thereby causing rotation of the plunger locking element  1090  about axis  1810 . The enlarged portion of  FIG. 92B  shows the rotation of the plunger engaging protrusion  1802  of the plunger locking element  1090  about axis  1810  such that it does not engage the plunger  1049 .  FIG. 92E  shows a slight bend in the resilient leg  1820  of the plunger locking element  1090  resulting from rotation thereof about axis  1810 . 
         [0327]    As seen in  FIG. 92A  and  FIGS. 92C-92D , the extent of rearward displacement of the needle guard element  1030  is selected such that the protrusion  1720  of the actuation button  1070  is still oriented with respect to the generally trapezoidal protrusions  1340  of the needle guard element  1030 , so as to prevent depression of the actuation button  1070 . 
         [0328]    Reference is now made to  FIG. 93 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86C  in a vial pumping orientation, to  FIGS. 94A and 94B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 93 , and to  FIGS. 95A ,  95 B,  95 C,  95 D and  95 E, which are sectional illustrations taken along respective section lines and directions XCVA-XCVA, XCVB-XCVB, XCVC-XCVC, XCVD-XCVD and XCVE-XCVE in  FIGS. 94A and 94B . 
         [0329]    As seen in FIGS.  86 C and  93 - 95 E, the plunger  1049  is rearwardly displaced, thereby drawing liquid from the interior of vial  1010  into the syringe  1046  via needle  1048 . The enlarged portion of  FIG. 95B  clearly illustrates that the plunger engaging protrusion  1802  of the plunger locking element  1090  is located above one of the teeth  1478  of the toothed portion  1477  of the plunger  1049 . 
         [0330]    Reference is now made to  FIG. 96 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86D  in a drug vial adaptor removal orientation, to  FIGS. 97A and 97B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 96 , and to  FIGS. 98A ,  98 B,  98 C,  98 D and  98 E, which are sectional illustrations taken along respective section lines and directions XCVIIIA-XCVIIIA, XCVIIIB-XCVIIIB, XCVIIIC-XCVIIIC, XCVIIID-XCVIIID and XCVIIIE-XCVIIIE in  FIGS. 97A and 97B . 
         [0331]    As seen in FIGS.  86 D and  96 - 98 E, the vial adaptor  1020  is removed from the forward housing  1040  by a user pressing the finger engagement surfaces  1226  of vial adaptor  1020  which disengages inwardly facing retaining protrusions  1230  from rearward recesses  1401 . The disengagement of the vial adaptor  1020  from the remainder of the injection device enables the needle guard element  1030  be forwardly displaced under the urging of spring  1032 , and the T-shaped protrusions  1342  stop pushing the downward facing protrusions  1822  of the plunger locking element  1090 . The plunger locking element  1090  rotates about axis  1810  back to its orientation shown in  FIGS. 87-89E  under the urging of the resilient leg  1820 . 
         [0332]    As seen in  FIG. 98B , the plunger locking element  1090 , once returned to its orientation shown in  FIGS. 87-89E , locks plunger  1049  by engagement of plunger engaging protrusion  1802  with teeth  1478  of toothed portion  1477  of the plunger  1049 , thereby preventing forward displacement of the plunger  1049  by a user.  FIG. 98E  shows that the resilient leg  1820  of the plunger locking element  1090  returns to its orientation shown in  FIGS. 96-98E  in which it is not bent and is located adjacent the forwardly facing protrusion  1912  of the rear end element  1080 . 
         [0333]    Reference is now made to  FIG. 99 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86E  in an actuated operative orientation, to  FIGS. 100A and 100B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 99 , and to  FIGS. 101A ,  101 B,  101 C,  101 D and  101 E, which are sectional illustrations taken along respective section lines and directions CIA-CIA, CIB-CIB, CIC-CIC, CID-CID and CIE-CIE in  FIGS. 100A and 100B . 
         [0334]    As seen in FIGS.  86 E and  99 - 101 E, the user pushes the automatic injection device against his body, thereby rearwardly displacing the needle guard element  1030  relative to the forward housing  1040 . As seen with particular clarity in  FIGS. 101A-101D , the rearward displacement of the needle guard element  1030  results in rearward displacement of the generally trapezoidal protrusions  1340  thereof, which no longer are oriented with respect to the L-shaped transverse outwardly facing protrusions  1720  of the arms of the actuation button  1070  so as to prevent actuation. Thus, the actuation button  1070  is free to be pressed by a user. Until the actuation button  1070  is actually pressed by the user, the flexible biasing fingers  1673  of the rear housing  1060  still engage corresponding second outwardly facing recesses  1718  of the legs  1704  of the actuation button  1070 , maintaining it in the “ready to inject” stage. 
         [0335]    As seen particularly in the enlarged portion of  FIG. 101A , the rearward displacement of needle guard element  1030  with respect to the remainder of the automatic injection device, resulting from engagement of the needle guard element  1030  with an injection site on a body, compresses spring  1032 . The rearward displacement of the needle guard element  1030  is limited by engagement of the forward facing edge of forward portion  1612  of rear housing  1060  with shoulders  1333  of arms  1319  of the needle guard element  1030 . As seen in  FIG. 101D , the rearward displacement of the needle guard element  1030  causes the T-shaped protrusions  1342  thereof to be further rearwardly displaced, such that they now are placed rearwardly of planar rearwardly facing surface  1828  of downward facing protrusions  1822  of the plunger locking element  1090 . It is noted that during this rearward displacement from the orientation of  FIG. 98D  to the orientation of  FIG. 101D , the plunger locking element  1090  is temporarily rotated out of locking engagement with the plunger  1049 , as illustrated in  FIG. 95D  and described hereinabove in the context of vial pumping. This transitional disengagement is normally imperceptible to the user. In the orientation of the needle guard element  1030  shown in  FIGS. 99-101E , pressing of button  1070  actuates the automatic injection device. 
         [0336]    Reference is now made to  FIG. 102 , which is a simplified assembled view illustration of the automatic injection device of  FIG. 61  in the orientation described hereinabove with reference to  FIG. 86F , where prior to pressing the actuation button  1070 , the user removes the automatic injection device from pressed engagement with his body, as indicated by arrow  1980  ( FIG. 86F ), to  FIGS. 103A and 103B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 102 , and to  FIGS. 104A ,  104 B,  104 C,  104 D and  104 E, which are sectional illustrations taken along respective section lines and directions CIVA-CIVA, CIVB-CIVB, CIVC-CIVC, CIVD-CIVD and CIVE-CIVE in  FIGS. 103A and 103B . 
         [0337]    As seen in FIGS.  86 F and  102 - 104 E, as the user displaces the automatic injection device away from his body, spring  1032  forwardly displaces the needle guard element  1030  relative to the forward housing  1040 . As seen with particular clarity in  FIGS. 104A and 104D , the forward displacement of the needle guard element  1030  results in forward displacement of the generally trapezoidal protrusions  1340  thereof, which are now closer to the L-shaped transverse outwardly facing protrusions  1720  of the legs  1704  of the actuation button  1070  than in the orientation shown in  FIG. 86E . 
         [0338]    If the user fully removes the automatic injection device from engagement with his body, the generally trapezoidal protrusions  1340  of the needle guard element are oriented with respect to the L-shaped transverse outwardly facing protrusions  1720  of the actuation button  1070  so as to prevent actuation. Thus, the actuation button  1070  is no longer free to be pressed by a user. This orientation is the same as shown and described hereinabove with reference to  FIG. 86D . 
         [0339]    Considering the transition from the orientation of  FIG. 86E  back to the orientation of  FIG. 86D  via the orientation of  FIG. 86F , it is seen particularly in the enlarged portion of  FIG. 104A  that during disengagement of the needle guard element  1030  with the body, the resulting forward displacement of needle guard element  1030  with respect to the remainder of the automatic injection device decompresses spring  1032 . As seen in  FIG. 104D , the forward displacement of the needle guard element  1030  causes the outwardly inclined surface  1346  of the T-shaped protrusions  1342  of the needle guard element  1030  to slide inwardly and forwardly alongside slanted backwardly facing surfaces  1828  of the downward facing protrusions  1822 , such that the forward facing protrusions  1344  now are placed alongside of downward facing protrusions  1822  of the plunger locking element  1090 , thus maintaining the plunger  1049  in a locked state. 
         [0340]    It is a particular feature of this embodiment of the present invention that throughout the transition from the orientation of  FIG. 86E  back to the orientation of  FIG. 86D  via the orientation of  FIG. 86F , pressing of button  1070  is prevented and thus ejection of fluid from syringe  1046  is prevented when the forward end of needle  1048  is not in the body. 
         [0341]    Reference is now made to  FIG. 105 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86G  in a needle penetration, pre-drug delivery operative orientation, to  FIGS. 106A and 106B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 105 , and to  FIGS. 107A ,  107 B,  107 C,  107 D and  107 E, which are sectional illustrations taken along respective section lines and directions CVIIA-CVIIA, CVIIB-CVIIB, CVIIC-CVIIC, CVIID-CVIID and CVIIE-CVIIE in  FIGS. 106A and 106B . 
         [0342]    As seen in FIGS.  86 G and  105 - 107 E, the user actuates the automatic injection device by once again pressing it against an injection site on his body, and inwardly displacing the actuation button  1070 . 
         [0343]    As seen with particular clarity in the enlarged portion of  FIG. 107B , the inward displacement of the actuation button  1070  displaces the actuation button engagement surface  1806  of forwardly extending protrusion  1808  of the plunger locking element  1090 , thereby rotating the plunger locking element  1090  about axis  1810  and releasing the plunger  1049 . Additionally, the protrusions  1540  of selectable driving assembly  1050  no longer abut against the rearward facing surfaces  1722  of the legs  1704  of the actuation button  1070 , and the selectable driving assembly  1050  is forwardly displaced under the force of spring  1062 . 
         [0344]      FIG. 107C  shows the inward displacement of the actuation button  1070 , which results in the flexible biasing fingers  1673  of the rear housing  1060  engaging the first outwardly facing recesses  1716  of the legs  1704  of the actuation button  1070 , and maintaining actuation button  1070  in an actuated orientation.  FIGS. 107B ,  107 D and  107 E show the rotation of the plunger locking element  1090 , which is caused by the inward displacement of the actuation button  1070 . 
         [0345]      FIGS. 107A and 107B  illustrate the forward displacement of the selectable driving assembly  1050 , accompanied by forward displacement of the syringe  1046 , which results in needle penetration. As seen in the first enlarged portion of  FIG. 107A , when the needle  1048  has fully penetrated the body, the forward displacement of the syringe  1046  is stopped by engagement of flange  1047  with protrusions  1460  and  1462  of the forward housing  1040 . The selectable driving assembly  1050  continues its forward displacement, thereby outwardly bending the first hinged fingers  1506  of the selectable driving assembly  1050  into a space formed by rectangular window  1322 , and releasing fingers  1506  from engagement with the flange  1047  of the syringe  1046 . 
         [0346]    The third hinged fingers  1526  of the selectable driving assembly  1050  are inwardly displaced by engagement of protrusions  1530  and  1532  with undercut forward edge  1632 , and the inwardly facing slanted protrusions  1528  of selectable driving assembly  1050  are located adjacent rearwardly facing shoulder  1475  of cylindrical portion  1474  of the plunger  1049 . The enlarged portion of  FIG. 107B  shows the rotation of the plunger engaging protrusion  1802  of the plunger locking element  1090  such that it no longer prevents the forward movement of plunger  1049 .  FIG. 107E  shows a slight bend in the resilient leg  1820  of the plunger locking element  1090 . 
         [0347]    During needle penetration, elastomeric motion damping elements  1052  and  1054  initially engage inclined recesses  1618  and then engage interiorly facing protrusions  1617 . As will be described hereinbelow, drug delivery follows needle penetration. 
         [0348]    Reference is now made to  FIG. 108 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86H  in a drug delivery operative orientation, to  FIGS. 109A and 109B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 108 , and to  FIGS. 110A ,  110 B,  110 C,  110 D and  110 E, which are sectional illustrations taken along respective section lines and directions CXA-CXA, CXB-CXB, CXC-CXC, CXD-CXD and CXE-CXE in  FIGS. 109A and 109B . 
         [0349]    As seen in FIGS.  86 H and  108 - 110 E, the selectable driving assembly  1050  continues its forward displacement, such that the inwardly facing slanted protrusions  1528  of the selectable driving assembly  1050  engage shoulder  1475  of the plunger  1049  and forwardly displace the plunger  1049 . The forward displacement of the plunger  1049 , which is illustrated with particular clarity in  FIG. 11A , results in injection of a drug into the body. 
         [0350]    Reference is now made to  FIG. 111 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86I  in an immediate post-drug delivery operative orientation, to  FIGS. 112A and 112B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 111 , and to  FIGS. 113A ,  113 B,  113 C,  113 D and  113 E, which are sectional illustrations taken along respective section lines and directions CXIIIA-CXIIIA, CXIIIB-CXIIIB, CXIIIC-CXIIIC, CXIIID-CXIIID and CXIIIE-CXIIIE in  FIGS. 112A and 112B . 
         [0351]    As seen in FIGS.  86 I and  111 - 113 E, the plunger  1049  is fully forwardly displaced and has reached the forward end of the syringe  1046 . As seen with particular clarity in the enlarged portion of  FIG. 113A , the outwardly facing protrusions  1532  of the third hinged fingers  1526  of the selectable driving assembly  1050 , which slid along interiorly facing surface  1614  of the rear housing  1060 , now slide along interiorly facing surface  1331  of the mounting arms  1319  of the needle guard element  1030 , while the inwardly facing slanted protrusions  1528  of the third hinged fingers  1526  of the selectable driving assembly  1050  continue to engage shoulder  1475  of the plunger  1049 . It is appreciated that forward displacement of both plunger  1049  and selectable driving assembly  1050  is stopped at this stage. Drug delivery is complete. 
         [0352]    Reference is now made to  FIG. 114 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86J  in its operative orientation as it is being disengaged from the injection site, to FIGS.  115 A and  1 - 15 B, which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 114 , and to  FIGS. 116A ,  116 B,  116 C,  116 D and  116 E, which are sectional illustrations taken along respective section lines and directions CXVIA-CXVIA, CXVIB-CXVIB, CXVIC-CXVIC, CXVID-CXVID and CXVIE-CXVIE in  FIGS. 115A and 115B . 
         [0353]    As seen in FIGS.  86 J and  114 - 116 E, the user is beginning to disengage the automatic injection device from his body, thereby enabling the needle guard element  1030  to be forwardly displaced under the force of spring  1032 . As seen with particular clarity in the enlarged portion of  FIG. 116A , during the forward displacement of the needle guard element  1030 , the outwardly facing protrusions  1532  of the third hinged fingers  1526  of the selectable driving assembly  1050  move along the interiorly facing surface  1331  of the mounting arms  1319  of the needle guard element  1030 , until they pass shoulder  1333  in the mounting arms  1319  of the needle guard element  1030 . The third hinged fingers  1526  of the selectable driving assembly  1050  snap outwardly once the shoulder  1333  of the needle guard element  1030  has been sufficiently forwardly displaced, thereby causing the disengagement of the inwardly facing slanted protrusions  1528  of the third hinged fingers  1526  of the selectable driving assembly  1050  from the shoulder  1475  of the plunger  1049 . At this stage, the selectable driving assembly  1050  does not engage the plunger  1049 , and selectable driving assembly  1050  can continue to be forwardly displaced under the force of spring  1062 , thereby forwardly displacing needle guard element  1030 . 
         [0354]    Reference is now made to  FIG. 117 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86K  in a needle protected operative orientation, to  FIGS. 118A and 118B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 117 , and to  FIGS. 119A ,  119 B,  119 C,  119 D and  119 E, which are sectional illustrations taken along respective section lines and directions CXIXA-CXIXA, CXIXB-CXIXB, CXIXC-CXIXC, CXIXD-CXIXD and CXIXE-CXIXE in  FIGS. 118A and 118B . 
         [0355]    As seen in FIGS.  86 K and  117 - 119 E, the selectable driving assembly  1050  continues to be forwardly displaced under the force of spring  1062 , thereby forwardly displacing the needle guard element  1030 . The forward displacement of the needle guard element  1030  is terminated by engagement of stop surfaces  1328  of the needle guard element  1030  with corresponding inwardly extending shoulders  1463  of forward housing  1040 , at which stage the needle  1048  is fully enclosed by the needle guard element  1030  and is locked with respect thereto. 
         [0356]    As seen with particular clarity in the enlarged portion of  FIG. 119A , the forward displacement of the selectable driving assembly  1050  results in the second fingers  1516  thereof being positioned forwardly of the flange  1047  of the syringe  1046 . This produces the positive locking of the needle  1048  with respect to the needle guard element  1030 . It is noted that the third hinged fingers  1526  cannot be bent inwardly at this stage due to engagement of inwardly facing slanted protrusions  1528  with cylindrical portion  1474 . 
         [0357]    Reference is now made to  FIG. 120 , which is a simplified assembled view illustration of the automatic injection device of  FIGS. 61 and 86L  in a needle-shield push back misuse operative orientation, to  FIGS. 121A and 121B , which are respective side and top view simplified planar illustrations of the automatic injection device of  FIG. 120 , and to  FIGS. 122A ,  122 B,  122 C,  122 D and  122 E, which are sectional illustrations taken along respective section lines and directions CXXIIA-CXXIIA, CXXIIB-CXXIIB, CXXIIC-CXXIIC, CXXIID-CXXIID and CXXIIE-CXXIIE in  FIGS. 121A and 121B . 
         [0358]    As seen in FIGS.  86 L and  120 - 122 E, when a user misuses the device and rearwardly displaces the needle guard element  1030 , the rearward displacement of the needle guard element  1030  results in rearward displacement of the selectable driving assembly  1050 . Shoulders  1333  of arms  1319  of the needle guard  1030  push against protrusion  1532  of the selectable driving assembly  1050 . Selectable driving assembly  1050  is therefore forced to undergo rearward displacement. Due to this rearward displacement of the selectable driving assembly  1050 , the second hinged fingers  1516  thereof engage the forward facing surface of the flange  1047  of the syringe  1046 . 
         [0359]    Continued rearward displacement of the selectable driving assembly  1050  results in rearward displacement of the syringe  1046  and needle  1048  together with the selectable driving assembly  1050  and the needle guard element  1030 , thereby ensuring that the needle  1048  is not exposed at any stage following injection. 
         [0360]    It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as modifications thereof which would occur to persons skilled in the art upon reading the foregoing specification and which are not in the prior art.
An injection device for injecting a fluid into an object, the injection device including a plunger assembly for operative engagement with a syringe adapted to contain the fluid and permit ejection of the fluid therefrom via a syringe outlet, the plunger assembly being displaceable in a first direction which causes at least some of the fluid contained in the syringe to be ejected from the syringe via the syringe outlet and an inadvertent fluid ejection prevention assembly coupled to the plunger assembly for preventing ejection of fluid from the syringe in situations where the syringe outlet is neither in operative engagement with a vial adaptor suitable for providing fluid communication with the interior of a vial nor in fluid communication with an injection site within the object.