referring now to fig1 the apparatus for driving the needle according to the invention is identified generally by numeral 1 and is shown supported on the casing or housing 2 of a sewing machine . this needle driving apparatus includes among its various parts a needle clamp 3 having a needle 4 and a sleeve 5 which is mounted to slide freely on a stationary needle bar 6 that is fixed to and extends from the housing 2 . the needle clamp 3 and the operatively associated sleeve 5 are interconnected by means of a hinge pin 7 assembled in the end 8 of a control lever 9 which is pivotably supported intermediate its ends on a crankpin 10 of a crank 11 . as shown in fig1 crank 11 is disk - shaped and is fixed on or forms an integral end of a control shaft 12 that is supported for oscillating movement in the housing 2 . this control shaft 12 is disposed perpendicular with respect to the control lever 9 . the end of the control lever 9 opposite end 8 is depicted by numeral 13 and carries a pin 14 which serves to pivotably connect said control lever with the lower end of a movable pivoting element that defines a lever 15 . the upper end of the lever 15 is pivotably mounted on a pin 16 which extends from and is supported by the housing 2 . the assembled position of the lever 15 on the pin 16 and its association with the control lever 9 is such as to cause said lever 15 to extend in a direction substantially parallel with the needle bar 6 which establishes the path of movement of the needle clamp 3 that will be more fully described hereinafter . the needle bar 6 does not force the needle clamp 3 to travel in a straight path , but serves to avoid tilting or moving about of the needle 4 because the end 8 of the control lever 9 and the needle clamp 3 operatively associated therewith both travel a path which is substantially straight . as is known in the sewing art , the path travelled by the needle clamp 3 is not a perfectly straight one , but can be considered to be so within a certain value of the travel of the needle clamp . the needle clamp 3 is reciprocated along that portion of the path corresponding to that which remains substantially straight by the crankpin 10 that is located a distance from the axis of the control shaft 12 which equals about 1 / 6 of the total length of the control lever 9 ( fig2 ). the crank 11 transmits its oscillations of approximately 50 ° to the control lever 9 by means of its pin 10 which moves reciprocatingly from the point a to the point b and vice versa along the arc &# 34 ; x &# 34 ; shown in fig2 . as the control lever 9 is pivoted on the lever 15 , the latter causes said control lever to follow the movements of the crankpin 10 along the arc &# 34 ; x &# 34 ; with a minimum of resistance . during these movements , the end 13 of the control lever 9 moves along the arc &# 34 ; y &# 34 ; formed by the pin 14 as it moves from the point c to the point d and vice versa in accordance with each movement of the crankpin 10 from a to b or from b to a . as shown in fig2 the selected location of lever 15 on the housing 2 is effective when the crankpin 10 arrives at point b of causing the end 8 of the control lever 9 to be in its uppermost position which is designated by the letter e . with the end 8 arriving in this position the needle clamp 3 has also reached its top dead - center position along with the sleeve 5 . movement of the needle clamp 3 in this manner is effective in causing it to travel a distance of approximately 24 mm . with a minimum of resistance . when a greater distance of travel of the needle clamp 3 is desired , the crank 11 is adjusted to cause it to oscillate a greater number of degrees by adjusting the known internal elements of the machine which are selectively set to control the degrees of oscillation of the control shaft 12 . the invention provides a means which compensates for increasing the oscillating distance of the crank 11 described above by providing a means for selectively changing the operating position of the lever 15 on the housing 2 whereby it can be selectively located in either positions f or g ( fig2 ). in this figure of drawing , numeral 15 &# 39 ; represents the location of the lever 15 after its operating position was selectively changed from position f to position g . position g , which is disposed adjacent and in slightly spaced relation to position f is calculated to tolerable values so as to reduce the difference between the actual path taken by the needle clamp 3 and the straight path represented by the stationary needle bar 6 , and especially in connection with the top dead center of the needle clamp . the lowermost point of travel of the needle clamp remains unchanged in both positions of the lever 15 for obvious reasons of timing so that the needle and loopers will cooperate at the same level for proper stitch formation . to provide the two positions for the pin 16 as location points for the lever 15 on the casing 2 , said pin is formed so as to project eccentrically from one end of a cylindrical stud 17 ( fig3 and 4 ) whereby the axis of the latter extends parallel with but slightly spaced from the axis of said pin . the eccentricity of this pin corresponds at two points , which are disposed diametrically opposite each other , to the two different locations for the lever 15 for selectively effecting a predetermined distance of travel by the needle clamp 3 . this cylindrical stud 17 is assembled in a suitable hole or seat 18 formed in the casing 2 . this seat 18 is located in a position intermediate the two selectively available locations for the lever 15 which govern the distance the needle clamp 3 is caused to travel during the performance of its intended function . by selectively rotating the cylindrical stud 17 in its seat 18 , the pin 16 can be quickly and easily located in either one of the two desired locations for supporting the lever 15 . to simplify this adjustment change and to accurately locate the pin 16 , the cylindrical stud 17 is provided with two planar surfaces 19 and 20 formed on the peripheral surface of said cylindrical member in diametric opposed relation . a set screw 21 assembled in a threaded hole in the housing 2 so as to engage one or the other of the planar surfaces 19 and 20 provides a means for fixing the position of pin 16 in the selected location for supporting the lever 15 . the needle driving apparatus according to the invention possesses what is considered a very desirable advantage of providing exceptional smoothness of needle clamp travel in both selectively available operating locations for the lever 15 . a further advantage is that of being able to utilize a single housing for machines having needle clamps capable of moving in pathways of different lengths and which do not require control components of different sizes to effect a change from one length of pathway to another . additionally , with the eccentric pin 16 forming a fixed element of the cylindrical stud 17 that is adjustably mounted in the housing 2 at a location intermediate the two positions at which it must operate to effect two different lengths of travel of the needle clamp , a means is provided for accurately locating the lever 15 within the range of the particular location desired . by simply rotating the cylindrical stud 17 within its seat 18 it is possible to correct any errors that may occur in the position of the pin 16 relative to the needle bar 6 and to correct the position of the lever 15 with respect to said needle bar . although the present invention has been described in connection with a preferred embodiment , it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily understand . such modifications and variations are considered to be within the purview and scope of the invention and the appended claims .