Exchangeable cartridge unit for automatic welders

Claim 1

In a miniaturized replaceable cartridge-type welding apparatus adapted for joining in a girth weld the adjacent ends of annular workpieces such as large diameter pipes and similar tubes which have a common axis at said adjacent ends definIng a general plane in which the girth joint is located, said cartridge being adapted to travel in an orbital path around said common axis and adapted to be entirely confined in an annular travel path, the combination which comprises a unit frame, a welding nozzle pivotally mounted in said frame for movement between a projected welding position and a retracted nonwelding position means for moving said nozzle between said positions, means on said unit frame for mounting a reel of consumable electrode wire with its axis perpendicular to the plane of the joint, a pair of wire feed rollers mounted in said unit frame with their axes perpendicular to the plane of the joint, a guide tube for the wire between the reel and said rollers, a flexible resilient guide tube for the wire between said rollers and the movable welding nozzle adapted to yield to the nozzle movement, a wire drive motor mounted with its axis generally in or parallel to the weld plane and to accommodate said close confinement, said motor being geared to one of said feed rollers for positive feeding and control of said wire, and quick release means on said unit frame for detachably securing the cartridge to an independently driven carrier which also travels orbitally about said common axis.