GB1358887A - Flash-off butt-welding machine - Google Patents

Abstract

1358887 Welding by pressure VS LIFSHITS VR ANDRIANOV NN RYKALIN TF KRASNEY NV PODOLA and VP KR1- VONOS 11 Nov 1971 52369/71 Heading B3R A flash-butt welding machine comprises a fixedly mounted work clamp 3, a movable work clamp 4 which can be hydraulically traversed by a hydraulic ram 7 towards and away from the fixed clamp under the control of a spool valve 8 supported by one of the clamps, and a spool valve actuating assembly 16 supported by the other of said clamps and which is responsive to a first means 11 for automatic control of the initiation of upsetting, a second means 15 for automatic control of the flashing rate and a third means 12 for automatic control of the amount of upset, said assembly comprising an actuator 29 for actuating the spool element 17, first and second drives 27, 28 and 19, 20 for moving the actuator 29 towards and away from the spool element, a stop element 30 for restricting movement of the actuator away from the spool element and a third drive 31 for positioning the stop element, said first, second and third drives being interconnected with the output of said first, second and third means 11, 15, 12 respectively. The cylinder 27 of the first drive means is rigidly connected to a hollow rod 21 which extends from the piston 20 of the second drive means and through which the actuator rod slidably passes. To initiate the welding process, i.e. the flashing stage pressure fluid is supplied by valve 24 and through an adjustable throttle valve 25 to compartment A of cylinder 19 pressure fluid at the same time being supplied to compartment D of cylinder 27. Thus piston 20, rod 21, cylinder 27, piston 28 and rod 29 commence to move to the right displacing spool 17 of valve 8 and traverse of the movable clamp commences. The flashing rate is preset by control means 15 which in operation receives converted voltage signals from windings of transformer 2 and provides an output signal to regulate a motor 26 connected to the valve 25 which controls supply of pressure fluid to cylinder 19 and thus also controls the rate of traverse of clamp 4. Temperature sensors 9 (Fig. 1) measure the workpiece temperatures and provide.signals to the control means 11, 12 to determine the point at which upsetting commences. This is effected by operating valve 34 so that pressure fluid is supplied to compartment C of cylinder 27 while valve 24 simultaneously moves to a neutral position thus fixing piston 20 relative to its cylinder 19. Thus rod 29 moves to the right to initiate upsetting. Sensor 10 measures displacement of the clamp 4 during the flashing stage and provides a signal to the control devices 11, 12 which in turn provide an output signal to a motor 31 which adjusts the position of a stop 30 adapted to be engaged by the right hand end of the rod 29. The position of stop 30 determines the extent of upset.