Patent GB-446409-A (GB)
Title: Improvements in and relating to machines for welding wires
IPC: B23K11/00
Filed: 1935-11-28
Abstract: 446,409. Making leading -in wires for electric lamps &c. BRITISH THOMSONHOUSTON CO., Ltd., Crown House, Aldwych, London. Nov. 28, 1935, No. 33039. Convention date, Nov. 28, 1934. [Classes 83 (ii) and 83 (iv)] Welding.-In an automatic machine for electrically welding wires end-to-end, two lengths of wire are supported in alignment and spaced apart, and separate means are provided to advance one of the wires towards the other to effect the weld. The machine may be used for welding three-part leading- in wires for electric lamps, radio tubes, &c., the wire consisting of a centre section of coated sealing wire and end sections respectively of nickel and copper. The nickel and copper wires 10, 11 are fed from opposite sides of the machine through guides 13, Fig. 3, clamping jaws 14, 15, and dies 17 on to grooved blocks 35 and between the jaws 55, 56 of pivoted grippers. The blocks 35 are carried by a pair of drums 36, which are intermittently rotated by Geneva and bevel gear from the shafts 43. The jaws 14 are spring- pressed and are raised during the feeding operation by slides 26 operated by levers 29 and cams 33 on the shafts 34. The drums are surmounted bv fixed shoes 53 provided with blocks 52 co - operating with the blocks 35. Each die 17 is mounted in a pin 39 attached to an arm 40 which may be oscillated by a cam 42 so that the die cooperates with a fixed knife 37 to sever a length of wire. The pin 39 engages an adjustable stop 45 to restore alignment with the block 35. The sealing wire 12 is fed through a die 57 and its end received in jaws 59, 60, Fig. 5, in a transferring arm which is oscillatable on a shaft 58. The jaw 60 is operated by an axially movable rod 69 through lever 68 and link 67. When the wire is received in the jaws, the die 57, which is carried on a pivoted arm is oscillated by a cam to co-operate with a fixed knife 71 so as to cut off the end of the sealing wire obliquely. The end 80 of this arm is adjustable. After the length is severed from the wire 12 it is transferred to a position in alignment with the wires 10, 11. Thereupon a contacting finger 83 connected in the electric circuit is brought down to engage the exposed end of the wire. This finger is carried by a two-part arm 85, 86, Fig. 6, passing through a block 90 which is pivoted at 91 and pushed down by a cam 95 against the action of a spring 97. In order to vary the pressure of the finger the part 86 is rotatably mounted in the block 90 and carries an arm 102 to which is pivoted at 101 a lever 100, one end of which is separated by a second spring from the arm and the other end of which engages a cam 98. The springs oppose each other. The lever 100 engages a nut on a stud extending from the arm. The wire 10 is now advanced towards the wire 12 to effect a weld by its gripper 55, 56, which is carried by one of a pair of levers 108 oscillated on pivots 121 by rods 124. The jaw 56 is closed by a toggle mechanism from a reciprocated rod. The lever 108 is mounted in a yoke 126, which is pivoted at 127 and may be vertically adjusted to the size of wire by a double wedge mechanism 148, 149, Fig. 11, operated by a screwed rod 143 through a hand lever 145. The rod is locked in position by a similar wedge mechanism operated by a knob 146. Each yoke 126 is also adjustable laterally by a screw 134 operated by a hand wheel 136 and fixed in position by a wedge mechanism operated by a screw provided with knob 142. Welding is effected by the discharge of one or other of condensers 156, 157 controlled by cam-operated contacts 158, 159, 177. The condensers are charged when the contacts 158, 159 engage spring-pressed contacts 160, 161 and 162, 163. In welding the wire 10 to the wire 12, the lead from the negative end of the condenser 157 is connected by contacts 173, 159, 174 to the gripper 55 through a polarity reversing switch 172 and the positive lead is connected by a variable resistance 175, contacts 176, 177, 178 and switch 172 to the seal wire contact mechanism 83. When this weld is effected the mechanism 83 withdraws and the lead from the negative end of the condenser 156 is connected to the wire gripper of wire 11 by way of contacts 179, 158, 180 and switch 171, while the positive end is connected to the gripper of wire 10 by way of variable resistance 181, contacts 182, 177, 183, switch 171 and the wire 11 thus welded to wire 12. On stopping the machine the condensers are short circuited by switch 184. The welded wires are indexed by the drums and when they pass from the shoes 53 are forced out by plates 189, Fig. 2.