Abstract: A welding seam back-up structure for mounting on the backside of the adjacently positioned edge margins of work members or workpieces that are to be joined by a weld seam, in which an elongate back-up tape of fiberglass or other suitable material is retained in a position bridging the backside of the edges to be joined, by means of an extrusion back-up tape holding structure having high heat conductivity characteristics and in one form is fabricated with at least one surface recess for receiving the back-up tape, the recess having a central longitudinal generally arcuate groove for conforming the backside weld bead, and longitudinally extending heat radiating fins. In another form, the extrusion is provided with a cover which coacts with the fins to provide a flow passage for a coolant fluid. In another arrangement the extrusion is reversible and has back-up tape receiving recesses on opposite sides.

Abstract: A welding seam back-up arrangement for mounting on the backside of the adjacently positioned edge margins of work members or workpieces that are to be joined by a weld seam, which is selectively variable as to length to accommodate it to weld seams of different lengths, and which comprises a plurality of tape engaging elongate channel members hingedly or otherwise interconnected in end-to-end relation and adapt it to be longitudinally positioned over a seam back-up tape of a material such as fiberglass, an elongate bar of a material having high heat conductivity characteristics, such as copper or aluminum, being interposed in the channel in underlying relationship to the tape to form a heat sink for conducting heat away from the weld seam during a welding operation.

Abstract: A track guided carriage unit for selectively supporting a variety of work performing devices, tools and the like for movement along a predetermined working path, in which a supporting platform has spring loaded wheels that are releasably clamped by a manually operable handle into and out of engagement with opposed surfaces of a guide track, and wherein a motor driven pinion has adjustable meshing relation with a linear rack extending along the track, the pinion being operative to advance the platform at a predetermined rate of guided movement along the work path.

Abstract: Welding apparatus in which a self-propelled wheeled carriage releasably supports a welding gun or torch of the hand-held type having a welding tip and control for controlling feed of a welding wire to the welding tip, wherein the carriage is guided along a joint to be welded at a predetermined proper welding speed, the welding gun being adjustably supported on a pivotally mounted cradle which is power-actuated to provide controlled oscillations of the welding gun and associated tip transversely of the joint at a rate of speed proportional to the propelled speed of the carriage, the amplitude of the oscillations being selectively adjustable between zero and a predetermined maximum. Interchangeable driving wheel units provide for use in the welding of planar disposed surfaces and angularly disposed surfaces.