Patent GB-570288-A (GB)
Title: Improvements in electric welding apparatus
IPC: B23K9/28
Filed: 1943-12-13
Abstract: 570,288. Uniting by fusion. LINDE AIR PRODUCTS CO. Dec. 13, 1943, No. 20803. Convention date, Dec. 18, 1942. [Class 83 (iv)] A manual electric welding apparatus cornprises an elongated hollow handle for receiving the electrode, on the forward end of which is mounted an annular bus-bar assembly for supplying welding current to the electrode, a starting or stopping switch on the handle at a point rearwardly of the bus-bar and a welding voltage indicator such as a voltmeter on the handle. By observing the reading on the voltmeter, the voltage and hence the distance of the end of the electrode from the work may be maintained constant. Welding is effected in a similar manner to that described in Specifications 433,723 and 543,416, in which the end of the electrode is submerged in a granular welding flux heaped on the work. A metal handle H may be secured by a split clamp 20 to a bushing 22 fixed by a screw 23 to one end of an insulating sleeve S, which at the other end is secured to a bushing 40 carrying a mounting for a voltmeter 43, and having a split clamp 42 for securing an insulating tube 44 on which the portion 60 of the bus-bar assembly is fixed by a split clamp 62. The busbar assembly has a slotted jaw J consisting of a series of flexible gripping fingers 73 adjusted by a split clamp 70 and secured in the bus-bar by a split clamp 61. The assembly carries a contact block to which one end of the welding current cable is attached. One terminal 53 of the voltmeter is secured to the bus-bar by a conductor 54, terminal 51, conductor 49 and clamp 50 and the other terminal 55 is connected by conductor 56 to the work. An insulating guard plate P may be bolted to the bus-bar assembly. Mounted on the sleeve S is an electrode feed member F, comprising a cylindrical block 80'mounted in a sleeve 77 between plates 78, 79 and provided with a bore 81 intersected by rearwardly converging passages 82, 83 containing spring-pressed aligning blocks 85 and rollers 86 which grip the electrode E when this feed member F is pushed forward by a tube 91 engaged by a tube 88 provided with a rack 89 meshing with a gear segment 30 on an operating hand lever 32. On return of the member F by a spring 75, the rod is held by friction of the contact jaw J. The rear end of the handle is threaded to receive an insulating bushing 37 with flared end, the bushing engaging an annular plate 35 through a felt washer 36. Mounted on the housing carrying the hand lever is a control switch C for starting and stopping the welding current, the switch being connected to conductors in a relay circuit operating the master switch of the welding circuit. In a modification, a rack 112 is fixed to a feed sleeve 101, 102, the latter part of which carries a stop collar 105 to engage the end of a bushing 98 secured in the handle H<1>. The rack engages a spur gear 107 which is riveted to a spur gear 108 rotated by a rack 115 mounted on the hand lever 32<1>, which is pivoted on roller bearings in lugs in the handle. The hand lever carries the remote control switch C<1>. The bus-bar assembly may be used as an electrode holder without the electrode feed, the assembly and the voltmeter being clamped on a tube such as 441. The contact switch may be carried by the voltmeter housing. Tubes of various lengths may be used.