GB678955A - Improvements in electric-arc stud and the like welding apparatus - Google Patents

Abstract

678,955. Welding by pressure. BOWLER & SIDNEY, Ltd., and BUTTERFIELD, T. L. H. Feb. 20, 1951 [March 6, 1950], No. 5604/50. Class 83 (iv). In an electric arc welding gun comprising a spring bellows reaction device forming an integral part of the gun and connected with a stud chuck spindle so that the device is energized by forcible application of the gun to the workpiece, means are provided to regulate the outward movement of the spindle under the reaction of the device so that the movement is first slow and is then sudden to drive the stud home. In an embodiment the gun has a body 1 with an extension 3 in which slides the stud chuck spindle 10 and a support spindle 27 for a foot 28. The spindle 10 supports a chuck 15 and carries an adjustable nut 13 below the extension 3 which limits the inward movement of the spindle 10. A spring bellows 5 is secured to a disc 9 on the spindle 10 and to a disc 6 fixed in the body 1 and provided with an aperture 19 which closely fits a spindle 21 extending from the disc 9. A further bellows 4 is secured to the disc 6 and to a member 8 engaging a coil spring 30 and having a recess 55 in which is engaged the upper end of the spindle 21 which is provided with passages 22, 23, 24. The bellows 4, 5 are filled with liquid. In operation the foot 28 is adjusted level with a fusible tip 18 on the stud 16 and with the foot 28 and stud 16 on the work a handle 2 is depressed. This movement compresses a spring 33 above the spindle 27 and compresses the bellows 5 to expel liquid therefrom into the bellows 4 through the aperture 19 and passages 22, 23, 24, which expands as the member 8 moves upwards to compress the spring 30. The nut 13 limits the movement and the passage 23 is finally located above the aperture 19. A lever 36 is pressed to pivot a clutch 32 which grips the spindle 27 and locks it relatively to the body 1. A switch 39 is actuated to send welding current through the stud 16 and work, thus fusing the tip 18 and starting an A.C. The unsupported stud 16 then moves slowly downwardly under the action of the spring 30 and bellows 4, 5, liquid in the bellows 4 slowly returning to bellows 5 through the aperture 19. After a slow movement the passage 23 becomes uncovered and liquid flows freely into the bellows 5 and the stud 16 is rapidly thrust into the work. A valve device comprising a two-diameter spindle extending from the disc 9 and through the aperture 19 is employed in a modification. The foot 28 may be dispensed with and the gun held in a static lever-operated machine. According to the Provisional Specification the welding current may be interrupted by a limit switch operated by the downward movement of the chuck spindle or by the drop in arc voltage. Specification 584,109 is referred to.