Patent GB-710722-A (GB)
Title: Improvements in or relating to electric arc stud welding or soldering guns
IPC: B23K9/20
Filed: 1951-11-23
Abstract: 710,722. Welding by pressure. SVENSKA AKTIEBOLAGET GASACCUMULATOR. Nov. 23, 1951 [Nov. 30, 1950], No. 27530/51. Class 83 (4) In an electric arc stud welding or soldering gun wherein the stud is automatically withdrawn from 'the workpiece to strike an arc when current flow is established, a time control arrangement provided for determining the duration of the arcing period comprises an arrangement whereby a length of fuse wire is included in the circuit so that the welding or soldering current passes through the wire, the wire being selected so as to fuse when the arc has been maintained for a desired period. In an embodiment a gun comprises a housing 1 having a cap 3 turnable thereon. Within the cap 3 is adjustably mounted a sleeve 4 having a porcelain ferrule surrounding a stud 9 on the end of a rod 7. An insulating ring 35 is secured in the cap 3 and is fixed to a metal sleeve 36 carrying an insulating hub 37 on which are mounted two diametrically opposed conductive jaws 38, 39, Figs. 1 and 2. The jaw 38 is connected by a slip ring 40 to a ring 33 fixed in an insulating body 34 but is insulated from the sleeve 36. The jaw 39 is insulated from the ring 40 but is connected to the sleeve 36. Three conducting shoes, one 55 is shown in Fig. 1, are screwed in the sleeve 36 to engage the rod 7. The jaws 38, 39 have axial grooves 41, 42, Fig. 2, in which spring clips 43, 44 are mounted. Peripheral grooves 47, 48 are also provided in which fuse wire 62 drawn from a reel 61 through a groove 63 is welded by projections 49, 50, Fig. 1, on the clips 43, 44. The ends of the clips 43, 44 are held in a groove 45, Figs. 1, 3, in a wall 51 of the housing. Current is supplied from a cable 13 through a magnetic hold on switch, operated by a button 25, to a solenoid 11 and by a conductor 32 to the ring 33. From the ring 33 current passes via the slip ring 40 to one jaw, through the fuse wire 62 to the other jaw, to the sleeve 36 and via the conducting shoes to the rod 7 and stud 9. In operation after pressing the stud 9 upon the workpiece so that stud 9 and ferrule 6 are both contacting it, the button 25 is pressed. Current is passed to the solenoid 11 which lifts the stud 9 and current passing through the fuse wire 62 to the stud strikes an arc. Then the fuse wire 62 fuses. Current is cut off and the stud is thrust by a spring 12 into the molten work. Before another weld can be made new fuse wire must be inserted. The cap 3 is turned anticlockwise as viewed in Fig. 2 to rotate the sleeve 36, hub 37, and jaws 38, 39. The end of clip 43 moves along groove 45 and when it reaches the extended portion 46 it springs up and ejects the fused wire. Further turning draws wire 62 from the reel 61 since one end is still held by clip 44 and turning is continued until the jaws 38, 39 have changed places when the clip 43 having moved out of the portion 46 grips the wire 62 in slot 41. When turning is commenced a spring urged rod 66 is urged out of a hole in a ring 65 fixed to the hub 37 to move a lever 68 to prevent operation of the switch. When turning is complete the rod 66 engages a diametrically opposed hole and allows operation of the switch. Specifications 681,585 and 681,586 are referred to.