GB560061A - Improvements in and relating to methods of welding - Google Patents

Abstract

560,061. Toothed gear wheels. BRITISH THOMSON-HOUSTON CO., Ltd. Sept. 28, 1942, No. 13600. Convention date, Sept. 29, 1941. [Class 80 (i)] [Also in Group XXII] In welding plates and a stiffening rib to each other and also to a rigid support member, the edges of the plates are fusion welded to the support member and the sides thereof are fusion welded to the side edges of the rib which is located between them so that one end is spaced from the support member, a joint member is interposed between the end of the rib and the surface of the support member so that the end portions of the joint member are spaced from the support member to form tapered gaps therebetween and are capable of deflecting to accommodate weld contractions, and the end of the rib is fusion welded to the mid-portion of the joint member and the assembly completed by attaching the opposite ends of the joint member to the support member by fusion welds which span the aforesaid gaps. Contraction strains due to the rigidity of the assembly, when the final weld is effected between the rib and support member are thus reduced before and during annealing of the assembly and cracked welds at this joint are thus avoided. Wheel-like structures such as toothed gear blanks, for use as part of a reduction gear for connecting high speed turbines to low speed propellers, or rotors for dynamo-electric machines may thus be made. A number of discs 12 .. 15 are, preferably after preheating, fusion welded at their inner and outer edges respectively to the forged steel hub 10 and forged steel rim 11 of a toothed gear blank, the edges being reduced in thickness on one side to provide grooves for weld metal, the other side being fillet welded. Yieldable lips are thus provided to take up contraction strains. The hub has a central enlargement to facilitate location of the discs 13, 14. Between the discs are fusion welded thereto the side edges of groups of radial stiffening ribs 16, 17, 18. The ribs are cut away in staggered form on opposite sides except at the ends, and the cut away portions of ribs on opposite sides of the same disc are also staggered so that the welds may yield to accommodate contraction strains. Some of the welds may be effected through openings 19 in the discs. The ends of the ribs, preferably prior to assembly of the parts, are fusion welded at 23 to joint members 22 of shape so as to leave, when assembled, tapered gaps between their under surface and the surface.of the hub. A flat member 22 would be used to co-operate with a curved hub surface or a curved member with a flattened hub surface. The member 22 is then fusion welded to the hub at 24 across the tapered gaps so that contraction strains may be provided for. The parts are machined before assembly and the outer edges of the discs tapered. Welding may be effected by the electric arc or other fusion welding process. The discs have staggered openings 20 for drawing oil from the interior.