Patent GB-1293532-A (GB)
Title: Improvements relating to methods of and apparatus for friction welding
Inventor: SEARLE JOHN GILBERT
IPC: B23K20/12
Filed: 1968-07-20
Abstract: 1293532 Welding by pressure JOHN THOMPSON (PIPEWORK & ORDNANCE DIVISION) Ltd 20 Oct 1969 [20 July 1968] 29462/72 Divided out of 1293531 Heading B3R In a method and apparatus for friction welding, contact pressure is maintained between faces of workpieces to be welded which are subjected to relative cyclic translatory movement,  the resultant movement involving excursions of the workpieces from a position in which the workpieces are required to be welded with means for decreasing the amplitude of the excursions to zero when a weld is to be formed. In a preferred embodiment holders 113, 114 are supported by means of leaf or blade springs 130, 132 so that holders 113, 114 are restricted to horizontal and vertical reciprocating movement respectively. Holder 114 is mounted to be moved along the axis 112 by a piston-andcylinder unit 115. Components of simple harmonic reciprocating motion are applied to the holders 113, 114 from a rotary drive motor 116 via transmission means 136a, 136b, including variable-throw cranks 144a, 144b. An adjustment means (not shown) moves slide blocks 141a, 141b along the slots 140a, 140b of levers 138a, 138b, respectively, to any desired position and no motion is transmitted to the holders when the slide blocks are moved into alignment with pivotal axes 139a, 139b. In an alternative arrangement the leaf springs may be supported at both ends and the holders 113, 114 mounted midway between the supported ends. In another embodiment, support means, Fig. 2  (not shown), may comprise a body portion  formed with a dove-tail section to slide in a  correspondingly shaped slideway formed in a guide member. Fluid under pressure may be supplied to the slideway thereby providing hydrostatic suspension for the holder. In a  further embodiment, Fig. 3, rectilinear reciprocating movement is transmitted to the workpiece 51 by a slide block 54 slidably mounted in a supporting frame 55. The spigots 57 cooperate with respective bores 56 in the slide block 54 and form a fluid-tight fit therein. Suitable sealing rings may be provided. Pistons 58 act within bores 59 which communicate directly with respective bores 56 which contain hydraulic fluid. Inlet and outlet ducts 60, 61 for circulating the hydraulic fluid are opened to the bores at the end of each stroke. The pistons having rollers are driven by respective eccentric elements 62 each comprising a cylindrical portion joined to another cylindrical portion offset from the axis of the first portion and being rotatable about one of the axes. The invention is further directed to several workpieces of a first set being welded to respective workpieces of a second set and reference is also made to opposite ends of an intermediate workpiece being joined concurrently to the ends of two terminal workpieces, and further to several workpieces being joined simultaneously to a large workpiece. In a modification of the apparatus of Fig. 6 two pistons are provided each with an extension of generally U-shape so that they may be driven from a common eccentric element.