Patent GB-1469606-A (GB)
Title: Friction welding apparatus
IPC: B29C53/00
Filed: 1975-10-22
Abstract: 1469606 Welding by pressure BRANSON ULTRASONICS CORP 22 Oct 1975 [25 Oct 1974] 43359/75 Heading B3R [Also in Division B5] Friction welding apparatus comprises a support 10 for holding a first workpiece W1; a platform 32 for holding a second workpiece W2 to be joined to the workpiece W1; electromagnetic force generating means 30, 30<SP>1</SP> for causing the platform 32 to reciprocate relative to the support 10 in a first plane; means coupling the platform 32 to the support 10 comprising yieldable members 36, 38 for causing the platform 32 to be at rest in the absence of the electromagnetic force and for enabling or causing the platform 32 to undergo reciprocation in response to the electromagnetic force while substantially inhibiting motion of the platform 32 in a second plane, perpendicular to the first plane, and for restoring the platform to rest upon cessation of the electromagnetic force; and means coupled to the support 10 for providing an engagement force between the workpieces W1, W2. In one embodiment, Figs. 1, 2, 4 and 5, the support 10 includes a removable plate 12 having a fixture 14 for holding the workpiece W1 and four pins 16 to be engaged by surfaces 20 of pivotable cam means 18 to draw the plate 12 upward against the support 10. The electromagnet force generating means comprises coil windings 30, 30<SP>1</SP> each disposed around the centre leg of an E-shaped core 28, 28<SP>1</SP> and wired to form a T-connection coil, Fig. 10 (not shown), to convert three-phase input power to two-phase output power. The platform 32 has a fixture 34 for holding the workpiece W2 and is coupled to the support 10 by leaf springs 36, 38 each having a thick end to provide a stop for the motion of the platform 32. The springs 36, 38 allow the platform 32 to reciprocate only in a direction 40. Magnetic cores 44, 44<SP>1</SP> are bolted to the platform 32. The windings 30, 30<SP>1</SP> are connected to a three-phase A.C. source and as each core 28, 28<SP>1</SP> is cyclically magnetized the respective core 44, 44<SP>1</SP> is attracted to reciprocate the platform 32. Alternatively, a D.C. source in combination with switching means may be used to alternately energize the coils 30, 30<SP>1</SP>. To keep the workpiece W1 substantially stationary during welding and to maintain it aligned with the workpiece W2, the piston 60 of an hydraulic pancake cylinder 58 produces a constant static force on the plate 12 by urging it against a set of adjustable spacer screws 62. To urge the workpiece W1 into contact with the workpiece W2, the piston 26 of a cylinder 24, Figs. 1 and 5 is coupled to a rotatable rod 72 the extending ends of which are provided with cams 18 clamped thereon. A rod 80 connects the rod 72 to a second rotatable rod 79 carrying two cams 18. Projection of the piston 26 causes the surfaces 20 to act on the pins 16 to press the workpiece W1 against the workpiece W2. To prevent reciprocation of the platform 32 until the workpieces W1, W2 have been forced together, a bifurcated spring plate 94, Fig. 9, is fixed to the rod 72 and, upon forward motion of the piston 26, is urged counterclockwise until the surfaces 20 engage the pins 16 and then the bifurcated ends of the plate 94 approach each other until an adjustable block 102 actuates a button 106 of a switch 100 to connect the coils 30, 30<SP>1</SP> to the power source. A threaded bolt 98 maintains the maximum gap when the piston is retracted. In a modification, Fig. 6, the platform 32 is coupled to the support 10 by rectangular section metallic bar leaf springs 86 secured at their ends to the support 10 and at their centres to the platform 32. In another modification, Fig. 7, vertically disposed spring plates 88 have apertures through which the cores 28, 28<SP>1</SP> pass and are connected to the support 10 and the platform 32. In a further modification (not shown), additional electromagnets are provided and by suitably energizing the magnets in timed relation the platform can be made to undergo twodimensional motion, e.g. circular or elliptical.