referring to the drawings , embodiments of the present invention will be described hereunder . fig1 through 11 show a first embodiment of the present invention . in these drawings , reference numeral 10 designates a lamp socket body ( hereinafter simply referred to a socket body ) made of an insulating material such as synthetic resin or the like and formed in a substantially cylindrical shape . a disc - like flange 11 is formed on the outer circumference of the socket body 10 . a lamp insertion channel 12 for inserting and supporting a base portion 52 of a wedge - base lamp 50 ( see fig8 ) is formed in one end opening portion of the socket body 10 , while a connector insertion channel 13 for inserting and supporting a connector 56 ( see fig2 and 4 ) is formed in the other end opening portion of the socket body 10 . the lamp insertion channel 12 is a recess portion of substantially i - shape in plan and surrounded by opposed vertical walls 14 and 14 and socket - body forming walls 10a . two terminals ( a plus terminal and an earth terminal ) 40 each having a pair of opposed contacting and sandwiching members 44 and 44 are oppositely provided inside the lamp insertion channel 12 . lead wires 53 of the lamp exit from the bottom of the lamp and are bent around toward narrow portions 54 formed in the base portion 52 , as shown in fig8 . accordingly , when the lamp 50 is inserted into the lamp insertion channel 12 , each of the narrow portions 54 is clamped by a pair of contacting and sandwiching portions 45 of the opposed contacting and sandwiching members 44 , so that the lamp 50 is prevented from falling out . the lead wires 53 and the contacting and sandwiching members 44 are electrically contacted with each other in fig8 reference numeral 55 designates a cylindrical post portion provided at the center of the base portion , and 55a is a spherical protrusion projected from the lower end of the post portion 55 . as shown in fig6 each of the terminals 40 is constituted mainly by a flat rectangular attachment - portion area 42 , the opposed contacting and sandwiching members 44 formed respectively at left and right side edge portions of the attachment portion area 42 , and a belt - like connector - side contact portion 48 formed under the attachment - portion area 42 . each of the attachment - portion area 42 of the terminal 40 fits in attachment grooves 12a formed in the socket - body forming wall 10a . bent portions 42a are formed at left and right side edge portions of the upper portion of each of the attachment - portion areas 42 . the bent portions 42a serve the function of positioning members in the front and back directions of the terminal ( the vertical directions in fig1 and the horizontal directions in fig5 ). a projecting portion 42b is formed on each of the attachment - portion areas 42 at its substantially center portion by partially cutting and bending the portion backward . the backward projecting portion 42b is engaged with a stage portion 12b ( see fig5 ) formed on the socket - body forming wall 10a so as to act as a locking mechanism . the contacting and sandwiching members 44 are made to be perpendicular to the attachment - portion area 42 and to extend up along the attachment - portion area 42 . the respective top end areas of the opposed contacting and sandwiching members 44 are bent so as to project inwardly ( in the direction such that the respective top end areas approach each other ) and then outwardly ( in the direction in which the respective top end areas become more separated from each other ) as they approach the respective top ends . the respective bent portions of the members 44 form the contacting and sandwiching portions 45 which act as spring members against the base portion 52 of the inserted lamp 50 so as to sandwich the narrow portions 54 of the base portion 52 therebetween . top end portions 44a of the opposed contacting and sandwiching members 44 are extended along upper end surfaces 14a 1 ( see fig8 and 9 ) of vertical - wall areas 14a facing the terminal housing portion respectively and are bent back to positions where the top end portions 44a do not interfere with the base portions 52 of the inserted lamp . as shown in fig6 the top end portions 44a of the contacting and sandwiching members 44 are bent to positions where they protrude a little outside the flat plate portion areas 44b of the contacting and sandwiching members 44 . as shown in fig4 and 5 , the respective connector - side contact portions 48 of the terminals 40 are projected into the connector insertion channel 13 so as to be in electrical contact with terminals of the connector 56 inserted into the connector insertion channel . reference numeral 13a designates a rubber packing and 57 designates a hook portion formed on the connector 56 so as to project therefrom . each of the terminals 40 is formed in the shape shown in fig6 by cutting a sheet of electrically conductive metal plate material 40a ( fig7 ) along the solid line and then bending at positions shown by broken lines . in fig7 the reference numerals 41 designate the cut lines , and 41a , 41b , and 41c designate notches for facilitating the bending of the contacting and sandwiching members 44 . particularly , the contacting and sandwiching members 44 are formed by partially cutting and bending the portions of the sheet of metal plate material so as to oppose to each other and so as to be perpendicular to the attachment - portion areas 42 respectively , and the contacting and sandwiching portions 45 are then curved arcuately , so that the base portion 52 of the lamp 50 can be easily led between opposed members 44 along the bent surfaces 45 . accordingly , the lamp 50 can be smoothly inserted substantially radially extending ribs 15 ( see fig1 ) are formed between the opposed vertical walls 14 forming the lamp insertion channel 12 and socket - body forming walls 10b opposed to the vertical walls 14 , respectively . upwardly projecting walls 16 are formed on the ribs 15 obliquely behind the contacting and sandwiching members 44 . the walls 16 have substantially l - shaped horizontal cross sections , and are extended from back positions of the vertical wall areas 14a facing the terminal housing portion to vertical - wall central - portion areas 14b forming the portion for housing the cylindrical post portion 55 of the lamp base portion . the walls 16 are made higher than at least the top end portions 44a of the contacting and sandwiching members 44 , and are high enough to cause the base portion 52 of a slantingly inserted lamp to abut against the inside corner portions 16a ( see fig8 and 10 ) without interfering with the top end portions 44a of the contacting and sandwiching members 44 . as shown in fig1 , the direction of insertion of the base portion 52 of the lamp is within a range between the arrows b 1 - b 2 , in which the socket - body forming wall 10b is not obstructive , in the conventional arrangement in which the walls 16 are not formed . on the other hand , in the invention wherein the walls 16 are provided , the direction of insertion of the base portion 52 is within a range between the arrows c 1 - c 2 . in fig1 , reference numerals 50b 2 , 50b 2 , 50c 1 , and 50c 2 designate lamp positions corresponding to the base - portion insertion directions b 1 , b 2 , c 1 , and c 2 respectively . that is , the insertion path of the base portion 52 is narrowed toward the lamp insertion channel 12 by a degree corresponding to the projection quantity of the walls 16 , so that , correspondingly , the base portion 52 does not interfere with the top end portions 44a of the contacting and sandwiching members 44 . further , the top end portions 44a are bent to the vicinity of the walls 16 , further preventing base portion interference with the top end portions 44a . the bent top end portions 44a are extended along the upper end surfaces 14a 1 of the vertical - wall areas 14a facing the terminal housing portion , and the upper end surfaces 14a 1 are formed so as to be lower than upper end surfaces 14b 1 of the vertical - wall central - portion areas 14b as shown in fig8 and 10 . that is , the upper end surfaces 14b 1 are higher than the top end portions 44a . accordingly , the base portion 52 of the lamp can abut against the vertical - wall central - portion area upper end portions 14b 1 but not against the top end portions 44a . the base portion 52 and the top end portions 44a of the contacting and sandwiching members 44 thus never interfere with each other not only in the case where the lamp 50 is slantingly inserted but also in the case where the lamp 50 is inserted in the state shifted from the axial center l as shown by arrow c 3 in fig1 . accordingly , the contacting and sandwiching members are never wrenched and deformed by the base portion as in the prior art . each of the contacting and sandwiching member top end portions 44a is sandwiched at its opposite sides by a vertical rib 12c forming the attachment groove 12a and a deformation preventing wall surface 14b 2 which is a side wall of the vertical - wall central portion area 14b , so that movement in the transverse direction ( the vertical direction in fig1 and the transverse direction in fig8 ) is restricted . in the case where the members 44 are excessively opened when a lamp is inserted , the top end portions 44a are made to abut against side surfaces 16b of the walls 16 ( see , fig8 and 10 ), and therefore the walls 16 have the function of preventing the contacting and sandwiching members from excessive opening . referring to fig1 , the state in which the base portion 52 of the lamp 50 is led into the lamp insertion channel 12 will be described hereunder . first , the base portion 52 of a lamp inserted in the direction shown by an arrow d 1 abuts on the inside corner portions 16a of the walls 16 and slides to the inside , so that the inserting direction is corrected to the direction shown by arrow d 2 . then , the cylindrical post portion 55 of the base portion 52 abuts on one of the central - portion area upper end surfaces 14b 1 of the vertical walls 14 , so that the base portion 52 slides to the inside without touching the top end portions 44a of the contacting and sandwiching members 44 . then , the lower - end spherical protrusion 55a of the base portion 52 enters between the vertical wall central - portion areas 14b and 14b . at that time , as shown by an arrow e , the base portion 52 is moved between the contacting and sandwiching portions 45 and 45 while pressing the opposed contacting and sandwiching portions 45 and 45 so as to separate one from the other . accordingly , the contacting and sandwiching portions 45 are engaged with the narrow portions 54 to thereby prevent the lamp 50 from falling out . although the top end bent portions of the contacting and sandwiching members 44 are formed so as to be lower than the upper end surfaces 14b 1 of the vertical - wall central - portion areas 14b in the above embodiment , the upper end surfaces 14a and 14b of vertical walls 14 may be flat with no stage as shown in fig1 so long as the top end portions 44a are bent back to the vicinity of the walls 16 . in this case , although the lamp base portion 52 can abut an area near one of the contacting and sandwiching portions 45 of the members 44 when a lamp is inserted as shown in fig1 , the base portion 52 slides along the bent surface of the portion 45 so as to be pressed between the opposed contacting and sandwiching members 45 . accordingly , also in this case , the lamp base portion 52 can be smoothly inserted without wrenching the contacting and sandwiching members 44 . the bend quantity of each of the contacting and sandwiching members 44 ( the position of each of the top end portions 44a ) and the projection of each of the walls 16 may be set under the condition that the inserted base portion 52 and the top end portions 44a of the contacting and sandwiching members do not interfere with each other . for example , with a larger projection quantity of each of the standing walls 16 , the quantity of each of the top end portions 44a may be made correspondingly smaller . on the contrary , the larger the bend quantity of each of the top end portions 44a , the smaller the projection quantity of each of the standing walls 16 . as is apparent from the above description , in the wedge - base lamp socket according to this embodiment of the present invention , the walls 16 are formed projectingly and obliquely behind the contacting and sandwiching members so as to narrow the insertion path of the lamp base portion , and so as to guide the base portion of the inserted lamp between the opposed contacting and sandwiching members . since the top end portions of the contacting and sandwiching members are located outside the base portion insertion path , the inserted base portion and the respective top end portions of the contacting and sandwiching member do not interfere with each other . according to the present invention , in inserting the lamp base portion , there is no fear that the contacting and sandwiching members will be deformed , so that the wedge - base lamp can always be smoothly inserted into the socket . further , the elasticity of the contacting and sandwiching members can be kept unchanged because there is no problem of wrenching and deformation or the like . referring to drawing fig1 - 21 , further embodiments of the present invention will be described hereunder . in fig1 - 18 , socket body 101 is made of an insulating material such as synthetic resin or the like so as to constitute a lamp insertion channel 111 for inserting and supporting a base portion al of a wedge - base lamp a and a connector insertion channel 112 for inserting and supporting a connector ( not shown ), the channels 111 and 112 being formed integrally with each other . two terminals ( a plus terminal and an earth terminal ) 102 , 102 are arranged in parallel to each other in the inside of the lamp insertion channel 11 , and each of the terminals 102 , 102 is provided with a pair of contacting and sandwiching members 121 for sandwiching the base portion al of the lamp a therebetween and for making electrical contact with a lead of the lamp a . each of the terminals 2 is made from one sheet of an electrically - conductive metal - plate material . that is , from the sheet of metal - plate material , the pair of contacting and sandwiching members 121 for sandwiching the base portion a1 of the lamp a therebetween and for making electrical connection with the lead wire of the lamp a , an attachment portion 122 to be inserted in and engaged with an attachment groove 113 of the socket body 101 , and a connector - side contact portion 123 to be electrically connected to the connector ( not shown ) are integrally formed to constitute the terminal 102 . the pair of contacting and sandwiching members 121 are bent and raised substantially perpendicularly to the attachment portion 122 so as to be able to sandwich the base portion a1 of the lamp a therebetween , and respective top end portions 121a of the contacting and sandwiching members 121 are outwardly bent arcuately continuously from the sandwiching portions 121b and 121b . by so forming the top end portions 121a of the respective contacting and sandwiching members , it is easy to lead the base portion a1 between the contacting and sandwiching members along the top end portions 121a when the lamp a is inserted . the possibility that the contacting and sandwiching members of the terminal may be wrenched and deformed by the base portion al of the lamp a is thus reduced . as shown in fig4 through 6 , one of the contacting and sandwiching members 121 may be inwardly curled to provide elasticity . in the inside of the lamp insertion channel 111 of the socket , walls 114 higher than the top end portions 121a of the contacting and sandwiching members 121 are integrally projectingly formed behind the members 121 , and deformation prevention walls 116 are integrally projectingly formed at side positions of the top end portions 121a . thus , stages 115 for preventing the contacting and sandwiching members 121 from excessively opening are formed between the walls 114 and the top end portions 121a . in other words , the walls 114 are projectingly formed behind the top end portions 121a so as to be slightly separated therefrom such that the top end portions 121a abut the walls 114 when they are excessively opened . the deformation preventing walls 116 act to restrict the transverse ( widthwise ) movement of the portions 121 so as to prevent the deformation thereof , and are projectingly formed at side positions of the portions 121a so as to be little higher than the top end portions . that is , in the case of the embodiment shown in fig1 through 18 , the top end portions are restricted as to transverse movement by the deformation preventing walls 116 and the attachment portions 122 of the terminal in the case of the embodiment shown in fig1 through 21 , one top end portion 121a of one of the contacting and sandwiching portions 121 is restricted in its transverse movement by the deformation preventing wall 116 and the attachment portion 122 of the terminal , while the other top end portion 112a of the other connecting portion 121 is restricted transversely by the projected deformation preventing walls 116 , 116 . with the wedge - base lamp socket configured as described above , even if the lamp is slantingly inserted into the lamp insertion of the socket body , the base portion of the lamp abuts against walls projected behind the contacting and sandwiching members of the terminals so as to make it impossible to insert the lamp into the insertion channel , or the direction of the base portion of the lamp is corrected so that the base portion of the lamp is properly aligned and inserted . further , the base portion of the lamp is restricted in its transverse movement by deformation preventing walls projected at the side positions of the top end portions of the contacting and sandwiching members , so that there is no possibility of the contacting and sandwiching members of the terminals being wrenched and deformed by the base portion of the lamp when the lamp is inserted . further , excessive opening ( excessive flexible deformation ) and transverse deformation of the contacting and sandwiching members can be prevented by the walls 114 and the deformation preventing walls . accordingly , the spring property of the contacting and sandwiching members can be maintained so as to cause the contacting and sandwiching members to firmly hold the lamp therebetween .