Welding apparatus for polygonal cross-sectioned tubing

The welding apparatus for producing a weld on a workpiece, said welding apparatus comprising:

• a housing having an internal opening, said workpiece to be located in said internal opening, said workpiece being tubular, said workpiece having a polygonal cross-sectional configuration;
• a welding electrode assembly mounted by mounting means on said housing, said welding electrode assembly being movable on said housing around said internal opening, said mounting means comprises:
• a driving assembly movably mounted on said housing, said welding electrode assembly being pivotally mounted on said driving assembly, said driving assembly to move said welding electrode assembly about the workpiece, said workpiece having an exterior surface, said welding electrode assembly including a welding electrode, said welding electrode having a longitudinal center axis, control means continuously maintaining said longitudinal center axis perpendicular to said external surface of said workpiece as said welding electrode moves around said workpiece, said driving assembly being composed of a plurality of separate connected members, locking means for securely connecting together said separate members in position around said housing, said locking means being releasable to disassociate said members from said housing, said connected members forming a totally enclosed area within which is located said housing, said connected members being hooked together through an engaging slot and shaft assembly;
• one of said connected members having a shaft mounted at each end thereof, a pair of said separate connected members each having at least one end formed into a slot, a said slot of one of said pair of said separate connected members engages with one of said shafts while the said slot of the other of said separate connected members engages with the other of said shafts;
• and
• one of said separate connected members being formed of two in number of members, said two in number of members being connected together by a third member, one of said two in number of members being slidable on said third member toward and away from the other of said two in number of members, a biasing means located about said third member exerting a continuous bias upon said two in number of members tending to locate said two in number of members as close together as possible, a pivotable cam mounted on one of said two in number of members, said pivotal cam to be pivoted pushing against the other of said two in number of members causing said two in number of members to move apart against the bias of said biasing means thereby permitting disassociation of said separate connected members from said housing.