GB1164317A - Improvements in or relating to Welding Devices. - Google Patents

Abstract

1,164,317. Welding by pressure. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 7 Nov., 1966 [10 Nov., 1965], No. 49784/66. Heading B3R. [Also in Division H2] Welding apparatus, such as percussive welding apparatus, comprises two workpieces 1, 2 originally in contact, which are subsequently separated to form an arc therebetween to melt the end of the member 1, contact between the workpieces then being re-established. With a switch 21 in its normal position capacitors 12, 19 are charged from sources 40, 30 respectively. Welding is initiated by operating the switch 21 into its dotted line positions whereupon controlled rectifiers 10, 18 become conductive to allow the capacitor 19 to discharge through the workpieces 1, 2. Simultaneously capacitor 12 discharges through the primary winding of a transformer 5, firstly by way of capacitor 6, from the lower end of the primary winding to the upper end and capacitor 7 and subsequently by way of inductor 9, from the upper end to the lower end of the primary winding and inductor 8. Thus the coil 4 of a permently magnetized electromagnetic device 3 is firstly energized in one direction to retract the member 1 from member 2 and thereafter energized in the opposite direction to restore the contact between the two members. The electromagnetic device may comprise two elements in parallel which are energized one after the other to cause opposing movements of the workpiece 1. The welding current can be adjusted by means of a variable inductor 14, 31 and in a second embodiment the rectifiers 10, 18 may be paralleled with further rectifiers which are controlled in accordance with the arc current so as to cause increases in the reversed energization of the coil 4 and in the welding current when an arc is formed.