Abstract: A weld backup mechanism includes an arcuate backup ring segment spring mounted to a support plate for rotational displacement. A plurality of such mechanisms are fixed to clamping members of an internal line-up clamp for radial expansion and retraction therewith.

Abstract: A device for cutting a metal or plastic jacket which surrounds a layer of foam on an insulated pipe is the subject of the present invention. A circumferential track mounts on the jacket and a ring gear is movable in the track. The cutting means is mounted on the ring gear for movement therewith. The cutting means is pivotally mounted so that it may assume a first position out of cutting engagement. Even in its non-cutting position, however, the leading edge of the cutting means will contact the jacket and movement in a circumferential direction will cause the cutting edge to penetrate the jacket and urge it into its cutting position. A motor is provided to drive the ring gear and cutting means around the track.

Abstract: A device for automatically welding a tube onto a pipe of larger diameter is the subject of the present invention. Tack welding is achieved by two welding torches located on opposite sides of the tube and spaced apart longitudinally a distance equal to the distance desired between tack welds. The entire torch assembly is mounted on a movable carriage that is motor driven. A frictional spool wheel engages the tube to drive the carriage while also serving as a guide wheel. Two cam wheels are also driven by the same motor that drives the carriage. One cam wheel controls operation of the welding torches on an intermittent basis. The second cam wheel controls the drive motor so that the latter is operated at a first speed during welding and a faster speed when welding in interrupted. This allows the device to traverse a given distance in less than half the time that would be required if the slower welding speed were maintained throughout the entire length of the tube.