GB1386105A - Resistance welding machine - Google Patents

Abstract

1386105 Resistance welding ACCRA-POINT ARRAYS 14 March 1972 11730/72 Head ing B3R In a resistance welding machine for welding an insulated wire 55 to a terminal element 57, a first electrode 54 is carried by a first carriage 31 movable relative to a base 11 on which there is a second electrode 22. A second carriage 32 is initially connected to the first carriage by magnetic attracting means, such as permanent magnet 44 on the second carriage and magnetic bar 46 on the first, and is moved by means such as air pressure-actuated piston 13 or a foot pedal mechanism (71-82, Fig. 2, not shown) so that the carriages move as a single unit into a welding position in which the first electrode 54 is urged into contact with the stationary element 57 which is in contact with the second electrode 22. The force exerted by said moving means (piston 13) is such that it breaks the insulation on the wire 55 but then overcomes the magnetic attraction between the carriages and the two separate. However, a spring, e.g. constant force spring 43, Fig. 1, or conventional extension spring 85, Fig. 3, provides a force of attraction between the two separated carriages which is less than the connecting force of the magnetic attracting means. Means for supplying the electrodes with current to make the weld under the pressure exerted by the spring, may include a switch 25, 26 actuated by the second carriage, or a switch 92, Fig. 3, actuated by an adjustable set screw 91 mounted on the carriage. In Fig. 2, the travel of the second carriage is limited by another adjustable set screw 88, the force exerted by extension spring 85 being dependent on the length of travel of the second carriage 32 after the first carriage has been stopped by engagement of the electrode 54 and wire 55 with the terminal 57. Dashpots 66, 65, Fig. 1, may be provided to absorb movement transients when the magnetic attraction is broken.