| 摘要 |
The welding of studs by a drop technique is provided, including provisions for the rapid feeding of the studs to a chuck. In this type of welding, a stud is held a predetermined distance above a workpiece with an electrical potential established therebetween. The stud is held in a chuck which, in turn, is carried by a ram. The stud, the chuck, and the ram are allowed to drop the predetermined distance to the workpiece, at which time the stud becomes fused thereto. Weights are often applied to the ram and the distance of the stud above the workpiece can be varied to achieve a proper weld for a particular workpiece. Means are provided to rapidly supply studs to the chuck and include a chuck leg forming a loading passage and carrying the chuck at an end thereof. A feed passage communicates with the side of the loading passage and feeds studs thereinto from a remote supply source. A back-up plunger is affixed directly to the ram and extends into the loading passage of the chuck leg. The back-up plunger is stationary and the chuck leg and the chuck are moved by a pneumatically-operated cylinder carried by the ram to position the back-up plunger behind the feed passage when a stud is being fed and to position the plunger near the chuck to back-up the stud when the stud is in welding position with an end protruding from the chuck. Since the plunger is affixed to the ram, it is rigid and the studs will not bounce during welding, as has heretofore occurred.
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