GB545986A - Improvements in and relating to welding apparatus - Google Patents

Abstract

545,986. Welding. BRITISH THOMSONHOUSTON CO., Ltd. July 25, 1941, No. 9438. Convention date, July 26, 1940. [Class 83 (iv)] A portable electric welding gun is constructed so as to minimize cable wear and fatigue to the operator by mounting the electrodes 11, 12 in a frame 10 which is mounted so as to be adjustable pivotally relatively to the conductors which are fitted with terminals 16, 17 which are apertured to receive a pivot 15. The pivot 15 is so secured at one end by a nut 25 and at the other end a hydraulically-operated clamp, which secures the electrodes in adjusted position and comprises a piston 22 in a cylinder 24 screwed to the terminal 16. The electrode 11 is fixed in a C-shaped part 59 of the frame 10 and the electrode 12 is carried by a bracket 32 secured to a piston which can slide in a cylinder 36 supported in brackets connected by bolts to the part 18 of the frame 10 which can swivel on the pivot 15. When liquid is admitted to the pipe 26 it can pass via a pipe 46 to the cylinder 36 and acts to press the electrode 12 into contact with the work before the clamping pressure is applied to hold the frame 10 in its adjusted position. The electrode 12 is retracted by a spring 56 in a casing 51 when the hydraulic pressure is released. The cable 13 is mounted in a ring 68 mounted in bearings 69 in an outer ring 70 secured to a support 67 which is suspended from the ceiling &c. The cable 13 also carries the tubes 71, 72 for supplying cooling fluid to the electrodes, and the tube for the power liquid. The bolts 40 are surrounded by sleeves of insulating material, and other parts are mounted so as to be insulated. In a modification the frame carrying the electrodes is pivoted to one terminal only, and the movable electrode is retracted by two springs arranged in series relationship. Cooling liquid is supplied to the frame as well as to the electrodes, and the device is supported by the aid of a bale screwed to it and having a sliding connection with a C- shaped arm suspended from the ceiling or the boom of a crane. The electrodes may be formed as in Specification 465,581.