GB575464A - Improvements relating to welding electrode holders - Google Patents

Abstract

575,464. Welding. MALLORY METALLURGICAL PRODUCTS, Ltd. March 18, 1944, No. 5063. Convention date, March 18, 1943. [Class 83 (iv)] An electrode holder of the ejector type for a resistance welding machine and comprising a tapered socket for the electrode tip with the interior substantially filled with liquid, has the electrode removed from the holder by applying hydrostatic pressure to the liquid. Electrodes may thus be ejected from a holder of odd shapes such as those having a bend or offset or a holder comprising the welding arm itself. A recessed electrode 13 may be fitted in a tapered socket of a holder 10, the larger bore of which contains water inlet and outlet valves 16, 17. Such bore contains a plunger 18 provided with a telescopic tube 25, 26 entering the recess 15, transverse and axial bores 23, 24 and an end 19 projecting through the rear end of the holder. Leakage of liquid round the plunger is prevented by packing rings 20, 27. The plunger may be provided with a perforated stop sleeve 28 of metal or rubber. The diameter of the plunger is sufficiently less than the bore of the holder in the vicinity of the passage 23 to permit water circulation round the plunger at this point. During normal operation the passage 23 is aligned with the passage of the valve 16 so that the cooling water is circulated therethrough. In order to remove the electrode 13, the valves 16, 17 are closed to isolate a volume of liquid in the holder and the projecting end of the plunger 18 struck, thereby applying hydrostatic pressure to the liquid contained therein to drive out the electrode. If desired, a cloth or container may be placed over the end of the electrode and holder to catch the electrode and some of the liquid. In a modification, the tube 25 is replaced by a tube 42, Fig. 3, having a flexible rubber or metal section 43 to convey liquid round the bend in the holder. In a further form having a holder with an offset end, the tube 25, 26 is also replaced by a tube 35, Fig. 2, having an end section 36 of rubber or other flexible material so as to convey liquid round the bends in the passage 37. The plunger may be returned by a spring 38 between the end thereof and a sleeve 39 resting against a shoulder inside the holder.