GB715686A - Improvements in or relating to methods of and apparatus for electric spot welding - Google Patents

Abstract

715,686. Welding by pressure. GENERAL ELECTRIC CO., Ltd., and DONELAN, J. A. March 17, 1952 [March 16, 1951], No. 6410/51. Class 83 (4). In electric spot welding two or more superposed pieces of material current is passed between two electrodes in contact with only one surface of one of the pieces to raise the material beneath at least one of the electrodes to welding temperature, the flow of current between the electrodes being solely through the material to be welded. Two welds may be made simultaneously by two rod-like electrodes of the same contact area. A single weld is made by one electrode 10, Fig. 3, about which is disposed an electrode 20 in the form of a fork having a larger contact area. One of the electrodes 10, 20 may be resiliently mounted and may project beyond the other. Each electrode may be mounted to apply pressure to forge the weld or welds. To produce a solid spot or ring-like weld between plates 12, 13, 14, Fig. 4, on an insulating backing 15, concentric electrodes 10, 30 are employed. Electrode 30 is insulated from electrode 10 by a bushing 31 on which it slides under a spring 32. Copper pieces between 0.003 and 0.02 inches thick may be welded to copper foil 0.0005 inches thick secured to a resin-bonded laminated insulating material. A multiplicity of welds may be produced by using groups of electrodes, those in one group being connected parallel together and insulated from those of the other group. Specification 509,548 is referred to.