Patent GB-1293531-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: 1293531 Welding by pressure JOHN THOMPSON (PIPEWORK & ORDNANCE DIVISION) Ltd 20 Oct 1969 [20 July 1968] 34726/68 Heading B3R  Apparatus and a method for friction welding workpieces comprises means for maintaining contact pressure between faces of the workpieces to be welded and drive means for moving the workpieces in a first mode of relative orbital movement and then subjecting the workpieces to a second mode of relative movement generally transverse to the first mode to discontinue the relative movement when a fused union is to be formed under pressure. As shown in Fig. 3 the workpiece holder 13 is connected to a piston- and-cylinder unit 15 energized pneumatically or hydraulically to urge together the end faces of the workpieces 10, 11. The holder 14 is driven with a translatory orbital motion from a motor 16. Eccentric elements in the form of crank discs 24, 25 convert the rotary motion of the motor 16 into the required translatory orbital motion. Crank-pins 26, 27 are adjustable in slots 24a, 25a to vary the eccentricity from zero to any predetermined value. In another embodiment, Fig. 4, the workpiece holders 113, 114 are supported by means of leaf or blade springs 130, 132 so that holder 113 is restricted to horizontal reciprocating movement and holder 114 to vertical movement. 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. In an alternative arrangement the leaf-springs may be supported at both ends and the holders 113, 114 mounted midway between the supported ends. Yet another alternative support means, Fig. 5 (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. 6, rectilinear reciprocatory movement is transmitted to the workpiece 51 by a slide block 54 slidably mounted in a supporting frame 55. The spigots 57 co-operate 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 axles. 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.