GB1279181A - Improvements in or relating to friction welding - Google Patents

Abstract

1279181 Welding by pressure CATERPILLAR TRACTOR CO 11 Feb 1970 [13 Feb 1969] 6599/70 Heading B3R A friction welding machine comprises means for relatively rotating the workpieces and forcing them into contact to generate sufficient heat to raise the temperature at the interface to a suitable bonding temperature the relative rotation then being allowed to subside to bond the pieces together, and the machine includes a motor 24 having a rotor shaft which forms a work spindle for one of the workpieces the shaft carrying workholding means. The machine preferably includes a motor 24 having a hollow through spindle with flywheels 66 and chucks 60, 62 at either end to carry workpieces 26, 28 (or a single workpiece extending through the spindle), the motor being disposed in a centre position between tailstocks 30, 32 which are mounted for sliding movement on guides 20 under the action of hydraulic rams 34, 36. The motor 24 may be fixedly mounted to the machine frame and to the guide 20 or alternatively (Figs. 8, 9, not shown) may be mounted for linear floating movement on the guide 20. In a further modification (Figs. 10-12, not shown) for welding at one end only of the motor spindle the motor is mounted to float on the guides and the thrust created during the welding operation is balanced by a rotary hydrostatic thrust bearing arranged at the other end of the motor spindle and pressurized simultaneously with the application of welding pressure to the workpieces. The drive motor 24 is preferably a low slip induction motor and a variable frequenty voltage may be applied to provide an efficient drive system having a high range of speeds. Work clamping means, Fig. 5, mounted on the tailstocks 30, 32 comprise two pairs of toggle levers 92, 101 and 92, 102, the levers 101, 102 carrying work clamping jaws 108, 110 and guide rollers 134, 136 and being arranged to perform an adjustable arcuate movement determined by arcuate guides 138, 140 on which the guide rollers 134, 136 bear. Actuation of the work clamping levers on each tailstock is effected by an hydraulic piston and cylinder 116, 118, connected by members 112, 114 to the pivot points 104, 106 of the toggle levers. Fixed supports 160, at the ends of the tailstocks locate and support the respective workpieces at the desired height until clamping is effected. The work clamping jaws 108, 110 and supports 160 are replaceable to accommodate various sizes of workpieces.