GB583671A - Improvements in electric welding rod guide and contact jaws - Google Patents

Abstract

583,671. Uniting by fusion. LINDE AIR PRODUCTS CO. Nov. 15, 1944, No. 22549. Convention date, Dec. 23, 1943. [Class 83 (iv)] A guide and contact jaw assembly for an electric welding rod comprises a body member with an elongated cavity which is open at one side and has secured therein a stationary current - conducting jaw, a movable current conducting jaw within the cavity, a flexible current conductor with one end secured to the body and the other to the movable jaw, and a leaf spring in the cavity between the movable jaw and the cavity closing means, the end portions of the spring bearing against the closing means and a rounded central portion bearing against the movable jaw. The relatively long contact jaws thus bear uniformly throughout their length against the welding rod and increase the area of contact therebetween and thus avoid arcing at points of imperfect contact, and ensuring uniform wear on the contacting surfaces. The jaws are composed of hardened beryllium-copper alloy. The coupling member C, which is secured to the welding head and carries the current supply cables comprises a hardened copper stem 10 and a collar 12 prodided respectively with passages 13, 14 for the rod R and a body with an elongated laterally-open cavity K in the end of which is secured by a screw 16 a stationary current conducting jaw Js provided with a guide groove 31 and bevelled ends 30 to facilitate entry of the rod. The movable jaw Jm with a flat surface is loosely suspended in the cavity by a flat copper braid conductor P secured by a screw 18 in a recess 35 in the stem, the conductor being secured to the jaw at 17 below its centre so that the jaw floats more freely within the assembly in operation and opens more readily when a rod is inserted through the jaw, regardless of the diameter thereof. The cavity is closed by a cylindrical case H of thermally and electrically insulating material which also prevents the entry of foreign material into the jaws. Between the' case and a strip 20 of, thermal insulation in contact with the conductor is mounted one or a number of arcuate leaf springs S of flat crosssection, the outer end portions of which bear against the case H and the central curved portion bears against the strip so that the resultant of the biassing forces passes substantially through the centre of gravity of the jaw so as to distribute the bearing pressure uniformly over the contacting surfaces. The number of springs used varies with the diameter 3 of the welding rod.