Patent GB-1233311-A (GB)
IPC: B23K11/00
Filed: 1969-03-27
Abstract: 1,233,311. Welding by pressure. AMP Inc. 27 March, 1969 [12 April, 1968], No. 15937/69. Heading B3R. [Also in Divisions H1 and H2] In welding at least two metal members together a welding current is passed through at least one of the members and through a foil, at least one member and the foil being urged into engagement to form an arc to consume the foil and heat the members and form the weld. Two copper or brass members A, B, Fig. 1, are abutted against an aluminium foil E, the nose of member A being rounded and that of member B being pointed. A capacitor circuit is connected between member A and the foil and when the capacitor C is discharged by closing switch SW an arc is formed causing the foil to vaporize and causing a radially expanding hole in the foil. The members A, B are urged together and the arc continues until the gap between the hole and the member is sufficient to extinguish it, a weld between the members A, B resulting. It is suggested that when the members initially contact member B also becomes an electrode and vaporization of the aluminium consumes oxygen to improve the weld. One member may be held fixed and the other held in a frame which is tapped with a hammer to cause the member to touch the foil and so initiate the arc, this an alternative to the switch initiation of Fig. 1. For welding a succession of workpieces, a tape of aluminium foil is unwound from a reel and passed between workpieces on opposite sides of the tape, the workpieces being urged towards each other and with a contact spring in contact with the tape a weld is made as in Fig. 1. The tape is advanced to a station where an exit in the wall of the aperture formed in the tape is made to permit the welded members to be removed. In a modification, each member is connected in a capacitor circuit with the foil and in another two co-extending members A, B, Fig. 5a, are welded by discharging a condenser between the members and a foil E by pressing the foil against the members by a tungsten member M. A ring tongue terminal portion 22, Fig. 7a, has a sleeve 24 which receives the stripped copper or brass core 14 of a conductor, the sleeve 24 being surrounded by a pair of insulating sleeves 25, 26 and a foil 28 being fitted between the sleeves and having an end 29 bent down. To weld the core to the sleeve 24, one welding current lead I is connected to the portion 22 and the other II to the foil and a tungsten member M is used to bear against the foil as in Fig. 5a. A solid core 14, Fig. 8, may be welded to a ring tongue terminal 34 surrounded by plastics sleeves 35, 36 having a foil 37 between them and bent down to cover the portion 34 by connecting the lead to one side of the welding circuit, the ring portion to the other and pressing the core 14 against the foil as in Fig. 1. The sleeves 35, 36 may be of heat shrinkable material to flow and seal the weld zone. A conductor may be welded to a ring tongue portion surrounded by a plastics sleeve and by a cap of aluminium (48), Fig. 9 (not shown), which provides a diaphragm-like end, the conductor being urged against the diaphragm as in Fig. 1. In a modfication, a pointed conductor is forced in to a plastics sleeve within an aluminium tube having a closed end for welding to a ring tongue portion. Two wires are welded together within a sleeve by the method shown in Fig. 1, using a foil trapped between the sleeve and an outer sleeve and in a modification two pointed conductors are welded, within a sleeve to the ends of a copper or brass plug (74), Fig. 12 (not shown), using a closed aluminium tube over the end of each conductor, the current supply being connected, between the centre plug and the aluminium tubes. One or two wires from a component may be welded to the head of a pin embedded in a circuit board, the head being beneath a thin foil pattern and the foil being employed to produce the arc and fusing to form a hole therein about the head of the pin. Leads from a component may be welded to patterns on the board using a disc of foil between the lead and the patterns.