Patent GB-1274861-A (GB)
Title: Improvements in or relating to apparatus for friction welding
Inventor: ELCOCK GERALD
IPC: B23K20/12
Filed: 1968-02-28
Abstract: 1,274,861. Welding by pressure. ELECTRI. CITY COUNCIL. 28 May, 1969 [28 Feb., 1968], No. 9687/68. Heading B3R. A machine for friction welding a first workpiece, e.g. a stud, to a second workpiece, e.g., a cable, comprises a clamp for the second workpiece, a chuck for the first workpiece, the clamp being arranged to add the second workpiece so that its longitudinal axis is perpendicular to the longitudinal axis of the first workpiece, a motor for rotating the chuck, means for urging the chuck towards the second workpiece and control means to stop rotation of the chuck and first workpiece and immediately increase the pressure of the first workpiece against the second workpiece. A portable apparatus for welding a stud - to an electric cable bared of insulation comprises a main housing 3, Fig. 1, within which a hollow piston 4 is slidable, the piston being movable to the left by fluid pressure supplied to chamber 81 and to the right by fluid pressure supplied to chamber 80. The piston 4 supports a bearing housing 5, an upchucking piston 10 with a return spring 36 and a retaining ring 11. The housing 5 supports an hydraulic motor 6 which drives a spindle 9 and provides between its reduced diameter portion 82 and piston 4, a cylinder for the piston 10 which actuates a three jaw chuck 83 carried by the spindle 9. Fluid from a port 84 moves the piston 10 to the left to move chuck body 24 to the left to allow the jaws 33 to open under the influence of springs 34 for the insertion of a stud, the jaws being closed when springs 8 move the body 24 to the right. A torque switch 1 is mounted beneath the housing 5 and a microswitch 45 is mounted beneath the housing 3. For clamping the apparatus to a cable, clamp housings 23, 25 are provided, the upper housing 23 being pivoted on a shaft 21 for latching over the cable and the lower housing 25 being pivoted on pins 18, the clamp being movable horizontally into engagement with the hook formed by the lower part of the housing 3 and the lower clamp housing 25 being pressurized by nuts 47 on bolts 46 engaging slots in the housing 25. Soft insulating jaws are bolted into the clamping housings. In operation an hydraulic control circuit is initially set so that the piston 10 is actuated to open the chuck and the piston 4 is fully retracted, a stud coated with insulating material over its cylindrical surface or fitted with an insulating glove is placed in the chuck and the piston 10 retracted to allow the chuck to close, and the apparatus is clamped on to a cable. The piston 4 is advanced, the motor 6 is started and when the rotating stud engages the cable frictional heat is generated. The pressure of the motor inlet is communicated to the pressure switch which, when the equilibrium torque conditions obtain, permits the motor to run as a pump and causes back pressure to be applied to retard the motor. An increased pressure is immediately applied to piston 4 to forge the weld. In a modified apparatus sliding jaws are employed instead of the cable clamp to hold a flat bar to which a stud is to be welded. In a further modified apparatus a stud rotating and pressure applying apparatus similar to that of Fig. 1 has a rotatable attachment nut (250), Fig. 15 (not shown), at its forward end which can be secured to one or other of two threaded portions 252, 253, Fig. 18, on a cable clamp. The chuck of the modified apparatus has a taper fitting in tapered elements in the driving spindle, the arrangement being such when the stud is pressed against the cable the taper system transmits torque.