Gripper for a welding gun and process for connecting a strip-form workpiece to a component

Abstract

The invention provides a gripper for a tack welding gun wherein the tack gripper is U-shaped in design. The tack gripper has two arms connected by a base. At least one arm of the tack gripper is resilient in design. The arms have a bent back portion at their free end. The portion is arranged between the respective arms. The portions contain holes in which the catch knobs formed on the workpiece to be welded can engage.

What is claimed:  
     
       1. A tack gripper for a tack welding gun, characterized in that the tack gripper ( 1 ) is designed in the form of a U with two arms ( 2 ,  3 ) connected via a base ( 4 ), at least one free arm ( 2 ,  3 ) of the tack gripper ( 1 ) being resilient. 
     
     
       2. A tack gripper according to  claim 1 , characterized in that at least one said arm ( 2 ,  3 ) has at least one hole ( 5 ,  6 ,  7 ) in a region ( 12 ) adjacent to its free end. 
     
     
       3. A tack gripper according to  claim 2 , characterized in that a plurality of holes ( 5 ,  6 ,  7 ) are provided, said holes being aligned transversely to the length of the arm ( 2 ,  3 ). 
     
     
       4. A tack gripper according to  claim 3 , characterized in that at least one said arm ( 2 ,  3 ) has, at its free end, a portion ( 8 ,  9 ) which is bent over itself, said portion ( 8 ,  9 ) being arranged between the arms ( 2 ,  3 ) and said holes ( 5 ,  6 ,  7 ) optionally being formed in the portion ( 8 ,  9 ). 
     
     
       5. A tack gripper according to  claim 1 , characterized in that each said arm ( 2 ,  3 ) is detachably connected to said base ( 4 ). 
     
     
       6. A tack gripper according to  claim 2 , characterized in that at least one arm ( 2 ,  3 ) can be spread against an additional spring force. 
     
     
       7. A tack gripper according to  claim 6 , characterized in that at least one spring element ( 10 ,  11 ) is arranged on at least one said arm ( 2 ,  3 ). 
     
     
       8. A tack gripper according to  claim 7 , characterized in that said spring element ( 10 ,  11 ) is a spring subjected to bending, the spring element ( 10 ,  11 ) being secured on one side in a region of said arm ( 2 ,  3 ) in which said arm ( 2 ,  3 ) at least partially overlaps said base ( 4 ). 
     
     
       9. A tack gripper according to  claim 8 , characterized in that said spring element ( 10 ,  11 ) is a leaf spring. 
     
     
       10. A tack gripper according to  claim 8 , characterized in that said spring element ( 10 ,  11 ) is curved in the form of an arc toward the arm ( 2 ,  3 ) at least at its free end. 
     
     
       11. A tack gripper according to  claim 10 , characterized in that said base ( 4 ) is formed by a cuboid carrier ( 13 ). 
     
     
       12. A tack gripper according to  claim 11 , characterized in that said arms ( 2 ,  3 ) and said spring element ( 10 ,  11 ) are screwed to said carrier ( 13 ). 
     
     
       13. A tack gripper according to  claim 12 , characterized in that each arm ( 2 ,  3 ) has a groove ( 14 ,  15 ), a pair of respective projections ( 16 ,  17 ) being formed on said carrier ( 13 ), said projections being engageable in said grooves. 
     
     
       14. A tack gripper according to  claim 13 , characterized in that said base ( 4 ) and said arms ( 2 ,  3 ) consist of bronze. 
     
     
       15. A tack gripper according to  claim 13 , characterized in that said arms ( 2 ,  3 ) are identical in design. 
     
     
       16. A tack gripper according to  claim 13 , characterized in that at least one of said base ( 4 ) and said arms ( 2 ,  3 ) have at least one cooling fin disposed thereon. 
     
     
       17. A tack gripper according to  claim 13 , characterized in that the base ( 4 ) has at least one cooling duct ( 31 ) which is connected to a coolant supply system. 
     
     
       18. A tack gripper according to  claim 17 , characterized in that said duct ( 31 ) is connected to the coolant supply system via a feed conduit and a discharge conduit. 
     
     
       19. A tack gripper according to  claim 17 , characterized in that the coolant is protective gas, water and/or air. 
     
     
       20. A workpiece which can be tack welded by means of a tack welding gun with a tack gripper according to  claim 15  to a component having at least a pair of gripping surfaces grippable by a tack gripper ( 1 ), wherein at least one of said gripping surfaces ( 21 ,  22 ) is formed with at least one catch knob ( 18 ,  19 ); at least one of said arms ( 2 ,  3 ) is provided with at least one hole ( 5 ,  6 ,  7 ); said catch knob being adapted to engage in said hole. 
     
     
       21. A workpiece according to  claim 20 , characterized in that said catch knobs ( 18 ,  19 ) are formed by embossment. 
     
     
       22. A workpiece according to  claim 20 , characterized in that said catch knobs ( 18 ,  19 ) have a height of 0.3 to 0.5 mm. 
     
     
       23. Process for connecting a strip-form workpiece (   20   ) to a component in which a tack gripper ( 1 ) of a tack welding gun according to  claim 1 , grips and frictionally secures a portion @of a metallic strip-form workpiece band, a separating device severs a strip of predetermined length from the band to form the workpiece (   20   ), the tack gripper ( 1 ) initially positions the workpiece ( 20 ) on the component and then welds it thereto and the tack gripper ( 1 ) is then removed from the workpiece ( 20 ). 
     
     
       24. A gripper for holding a workpiece in a welding gun for presentation to and attachment by welding on a body, said gripper comprising: 
         a mounting base  (   4   )  adapted for connection to a welding gun;    
         a pair of metal arms  (   2 ,  3   )  attached to opposing sides of said base and extending from said element in spaced relationship;    
       
         the free ends of said arms being bent in a U-shape and extending back toward said base; and  
       
       
         at least one of said arms being resilient to enable said arms to receive and frictionally retain a workpiece between said arms. 
       
     
     
       25. Process for connecting a strip- form workpiece  (   20   )  to a component in which a gripper  (   1   )  of a welding gun according to    claim 24   , grips and frictionally secures a portion of a metallic band, a separating device severs a strip of predetermined length from the band to form the workpiece  (   20   ) , the gripper  (   1   )  initially positions the workpiece  (   20   )  on the component and then welds it thereto and the gripper  (   1   )  is then removed from the workpiece  (   20   ) .   
     
     
       26. A gripper according to  claim 24 , characterized in that at least one said arm (   2 ,  3   )  has at least one hole  (   5 ,  6 ,  7   )  in a region  (   12   )  adjacent to its free end.   
     
     
       27. A gripper according to  claim 26 , characterized in that a plurality of holes (   5 ,  6 ,  7   )  are provided, said holes being aligned transversely to the length of the arm  (   2 ,  3   ) .   
     
     
       28. A gripper according to  claim 27 , characterized in that at least one said arm (   2 ,  3   )  has, at its free end, a portion  (   8 ,  9   )  which is bent over itself, said portion  (   8 ,  9   )  being arranged between the arms  (   2 ,  3   )  and said holes  (   5 ,  6 ,  7   )  being formed in the portion  (   8 ,  9   ) .   
     
     
       29. A gripper according to  claim 24 , characterized in that said arm (   2 ,  3   )  is detachably connected to said base  (   4   ) .   
     
     
       30. A gripper according to  claim 25 , characterized in that at least one arm (   2 ,  3   )  can be spread against an additional spring force.   
     
     
       31. A gripper according to  claim 29 , characterized in that at least one spring element (   10 ,  11   )  is arranged on at least one said arm  (   2 ,  3   ) .   
     
     
       32. A gripper according to  claim 31 , characterized in that said spring element (   10 ,  11   )  is a spring subjected to bending, the spring element  (   10 ,  11   )  being secured on one side in a region of said arm  (   2 ,  3   )  in which said arm  (   2 ,  3   )  at least partially overlaps said base  (   4   ) .   
     
     
       33. A gripper according to  claim 32 , characterized in that said spring element (   10 ,  11   )  is a leaf spring.   
     
     
       34. A gripper according to  claim 32 , characterized in that said spring element (   10 ,  11   )  is curved in the form of an arc toward the arm  (   2 ,  3   )  at least at its free end.   
     
     
       35. A gripper according to  claim 34 , characterized in that said base (   4   )  is formed by a cuboid carrier  (   13   ) .   
     
     
       36. A gripper according to  claim 35 , characterized in that said arms (   2 ,  3   )  and said spring element  (   10 ,  11   )  are screwed to said carrier  (   13   ) .   
     
     
       37. A gripper according to  claim 36 , characterized in that each said arm (   2 ,  3   )  has a groove  (   14 ,  15   ) , a pair of respective projections  (   16 ,  17   )  being formed in said grooves  (   13   ) , said projections being engageable in said grooves.   
     
     
       38. A gripper according to  claim 37 , characterized in that said base (   4   )  and said arms  (   2 ,  3   )  consist of bronze.   
     
     
       39. A gripper according to  claim 37 , characterized in that said arms (   2 ,  3   )  are identical in design.   
     
     
       40. A workpiece adapted to be held by a gripper according to  claim 34 , said workpiece having at least a pair of gripping surfaces; at least one of said gripping surfaces (   21 ,  22   )  being formed with at least one catch knob  (   18 ,  19   ) ; at least one of said arms  (   2 ,  3   )  being provided with at least one hole  (   5 ,  6 ,  7   ) ; said catch knob being adapted to engage in said hole.   
     
     
       41. A workpiece according to  claim 40 , characterized in that said catch knobs (   18 ,  19   )  are formed by embossment.   
     
     
       42. A workpiece according to  claim 40 , characterized in that said catch knobs (   18 ,  19   )  have a height of  0 . 3  to  0 . 5  mm.   
     
     
       43. A gripper according to  claim 37 , characterized in that at least one of said base (   4   )  and said arms  (   2 ,  3   )  have at least one cooling fin disposed thereon.   
     
     
       44. A gripper according to  claim 37 , characterized in that the base (   4   )  has at least one cooling duct  (   31   )  which is connected to a coolant supply system.   
     
     
       45. A gripper according to  claim 44 , characterized in that said duct (   31   )  is connected to the coolant supply system via a feed conduit and a discharge conduit.   
     
     
       46. A gripper according to  claim 44 , characterized in that the coolant is protective gas, water and/or air.