GB1180454A - Improvements in or relating to Resistance Welding - Google Patents

Abstract

1,180,454. Welding by pressure. WELWYN ELECTRIC Ltd. 6 Nov., 1967, No. 50434/67. Heading B3R. [Also in Division H2] Apparatus for resistance welding a termination lead to an electronic component comprises a fixed electrode and electromagnetic means for periodically moving a movably mounted electrode towards the fixed electrode to enable welding to be effected, means for periodically moving apart the two electrodes, means for supplying welding current when the component and lead are in mutual welding relation and means to ensure the existence of a gap between the two electrodes when said electromagnetic means is actuated and to limit the extent of travel of said movably mounted electrode. A resistor or capacitor 3 provided with an end cap 1 a metallized area, is gripped in fixed electrodes 4, 5 while the terminal lead 2 is clamped by a movable electrode 12 mounted on a support 14 pivoted at 21. The support 14 abuts an adjustable stop 18 such that a variable gap 23 exists between the support and an electromagnetic core 16 when the electrodes are held apart (as shown) by e.g. a solenoidoperated device 20. Upon de-energization of coil 19 the support 14 and electrode 12 are urged by tension spring 22 to rotate about pivot 21 such that the tip 24 of the terminal lead abuts the end cap of the component. A current pulse in coil 17 attracts a ferritic part 15 of the support 14 and a short while later a welding current pulse is fed to the electrodes from a pulse circuit (Fig. 3, not shown), so that the terminal lead is fed into the weld as the tip 24 melts. Thereafter, the electrode 12 releases the terminal lead and the coil 19 is re-energized to retract the electrode 12 against the stop 18. In a modification (Fig. 2, not shown), the tension spring 22 and pivot 21 are replaced by a torsion bar (26). The opening and closing of the jaws of electrode 12 is effected through rollers (31) bearing on surfaces (34) of pivoted levers (32) and operated by a Bowden cable (29). The welding current pulse may be derived from a capacitor discharge.