Multi-head resistance welding apparatus

Claim 1

A multi-head resistance welding apparatus for simultaneously securing a plurality of resistance welding pins to unite a composite including a metal substrate having an insulating layer thereon, said composite being moved in a predetermined horizontal direction, comprising a frame, a horizontal work support surface on said frame, an elongated support beam on said frame disposed above and in parallel spaced relation to said work support surface, a plurality of resistance welding assemblies mounted in spaced relation along said beam, said assemblies each including linear motor means shiftable in a vertical direction toward and away from said support surface, electrode means mounted on the lower end portions of each of said motor means, automatic means on said weld assemblies for sequentially feeding headed weld pins from a bulk supply, carrier means on said electrode means for receiving pins from said suPply, said carrier means supporting said pins while in welding position for movement relative to said electrode in said predetermined horizontal direction while maintaining a conductive connection between said pins and said electrode, whereby said pins are retained on said carrier in position to be welded to said substrate notwithstanding relative movement between said pins and electrode resulting from contact of said pins and said moving insulating layer.

Claim 10

The method of attaching a weld pin to a continuously fed metallic substrate through insulation layer of substantial thickness carried by said substrate by resistance welding, comprising continuously frictionally urging said substrate along a predetermined linear path over a support surface, progressively advancing an electrode carrying a weld pin toward said substrate in a direction normal thereto, progressively to urge said pin through said layer and into contact with said substrate supported on said surface, said pin being supported on said electrode for movement in the direction of said linear path and being in conductive contact therewith, thereafter increasing the pressure with which said pin is forced against said substrate to a value sufficient to stall movement of said substrate in said direction, causing a welding current to flow through said electrode, pin and substrate to weld said pin to said substrate, and thereafter relieving the pressure exerted by said electrode on said head to permit continued feed of said composite.

Claim 11

The method of attaching a weld pin to a continuously fed metallic substrate through insulation layer of substantial thickness carried by said substrate by resistance welding, comprising continuously frictionally urging said substrate along a predetermined linear path over a support surface, progressively advancing an electrode carrying a weld pin toward said substrate in a direction normal thereto, progressively to urge said pin through said layer and into contact with said substrate supported on said surface, said pin being supported on said electrode for movement in the direction of said linear path and being in conductive contact therewith, thereafter increasing the pressure with which said pin is forced against said substrate to a value sufficient to stall movement of said substrate in said direction, causing a welding current to flow through said electrode, pin and substrate to weld said pin to said substrate, and thereafter relieving the pressure exerted by said electrode on said head to permit continued feed of said composite.