GB662806A - Improvements in welding guns - Google Patents

Abstract

662,806. Uniting by fusion. AIR REDUC- .TION CO., Inc. June 13, 1949 [June 29, 1948], No. 15688/49. Class 83 (iv). In an arc welding gun with a continuously fed inert gas-shielded electrode 5, a nozzle 54 providing an annular gas stream at least twice 'as thick as the diameter of the electrode, forms an extension to an annular passage between a cylindrical casing 41 and an internal current pick-up shoe 56 of a length at least twice the diameter of the electrode. The electrode is fed to the gun through a T-fitting 11 by electric motor-driven rollers controllable from a switch 19 disposed in the pistol grip 15 of the gun and 'operating a solenoid which, on switching the motor on or off, simultaneously switches on or off a solenoid-operated valve controlling the supply of helium, argon or the like to a connection 13 on the fitting 11. One end of the fitting 11 is sealed by a rubber washer 60 and the other is connected to flexible conduit 12 through which the electrode and gas pass to the gun. The gun comprises a casing 41 of non-conducting moulded material with an internal conducting shoe 56 supported in a conducting block 42 which is connected to a welding current conductor 17 and to the conduit 12 and has circumferentially spaced passages for the gas. The forward end of the gun has an extension 52 of non-conducting material carrying the nozzle 54 and supporting the shoe 56 within a spacer 58 having circumferentially spaced passages 59 on the outer periphery for directing the gas axially. The nozzle 54 is preferably of copper and has cooling fins 55, and the internal diameter is such that the annular gap around the shoe 56 is more than twice the diameter of the electrode. The pick-up shoes are interchangeable for electrodes of different diameters, the internal diameter of the shoe being in each case slightly larger than the diameter of the electrode. A guard 51 is provided to shield the operator's hand.