Device for welding tubes to pipe

摘要

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.