Patent GB-973614-A (GB)
Title: Automatic electric condenser welding machine for production of lead-in wires for incandescent lamps and other light sources
IPC: B23K11/26
Filed: 1961-10-26
Abstract: 973,614. Making leading-in wires for electric lamps; welding by pressure; unwinding; shearing. TESLA, NARODNI PODNIK. Oct. 26, 1961 [Nov. 2, 1960], No. 38356/61. Headings B3A, B3E, B3R and B3W. [Also in Division H1] In a machine for making leading-in wires, two end wires and a central wire are simultaneously welded end-to-end by resistance welding using condenser discharge. The central wire is boraxcoated copper-plated steel and the outer wires are nickel or nickel plated iron and a copper-manganese alloy, respectively. Unreeling and feeding end wires 171, 172.-Identical mechanisms are used for each of the end wires disposed symmetrically about the centre of the machine. End wire 171 is supplied from a reel 175, Figs. 1 and 11, to a reciprocating gripper feed mechanism on a slide 119 through an eye 128 on an arm 130 and a rotary straightener 135. A mercury switch 133 on the arm 130 actuates an electromagnetic clutch to couple the reel 175 to the main cam-shaft 188 when the arm 130 senses that the loop of wire between the reel 175 and a guide roll 134 is insufficient. The feed gripper jaws in the slide 119 are opened against spring action by a lever actuated by a cam 111. The slide 119 is reciprocated by a crank disc and connecting rod device 180 having an adjustable stroke and driven from the cam-shaft 188. Feeding and shearing central wire.-The copper-plated wire 23 is drawn from a reel 107, Fig. 9, through an annealing furnace 108 and a straightener 110 by a reciprocating gripper 192 actuated by a cam 94 through levers 96, 103. The stroke of the gripper 192 is adjusted by altering the contact point between the levers 96, 103, by a screw 100. The jaws of the gripper are opened by a cam 83. The wire 23 is fed into a pivotally mounted cutting die 79 which is deflected from its cutting position by a cam controlled electromagnet to guide the wire between jaws 20, Fig. 3, of a transfer device 193. The wire 23 is severed by a cam-actuated sintered carbide blade 78 co-operating with the cutting die 79. Welding.-The sheared wire 23 gripped between the jaws 20 which are actuated through a push-rod 19 by a cam 14 is transferred into the welding position by angular movement of the device 193. A spring-loaded tungsten pin 24 having a sharpened end is slidably mounted in the upper jaw of the transfer device 193 and is released by a detent 29 to pierce the borax coating of the wire 23 and to make electrical contact with the wire. Each inner end of the wires 171, 172 is gripped by cam-operated jaws 194, Fig. 5, carried on an arm 53 suspended on a leaf spring 54. Cams 40, 41 act through adjustable levers 43, 52 to move the arms 53 to produce an upsetting action between the abutting wires 171, 23, 172. The welding current is derived through a transformer 152, Fig. 13, from a bank of condensers 146, selectible by switches 147. A cam 144 actuates a switch to alternately charge the selected condensers 146 and discharge them through a thyratron 151. Shearing the welded wire.-The welded leading- in wire is severed by cutters 186 mounted on each slide 119 and falls into a trough 187.