AUTOMATIC WELDING APPARATUS FOR POLYGONAL WORKPIECES

摘要

Automatic welding apparatus for making uniform welds around the perimeter of a polygonal shape made up of a succession of flats and arcuate corners is described in connection with a tubular hexagonal workpiece which is rotated about its longitudinal axis beneath a welding torch assembly. The distance of the welding electrode above the workpiece is maintained as preselected by automatic voltage control means. The welding electrode is automatically maintained perpendicular to a tangent to the surface of the workpiece and extending in the plane of the weld line by oscillating the welding torch assembly so that its longitudinal axis describes an arc having its center on the longitudinal axis of rotation of the workpiece in synchronization with the rotation of the workpiece. Synchronization is provided by means of an annular cam surface which is rotated in predetermined relation to the workpiece and which controls the oscillation of the welding torch assembly.