Improved coupling device for the orbital butt welding of medium and large metal pipes

摘要

The device comprises a set of expansion trucks (15a-15b) which can expand against the internal surface of the pipes for positioning, retaining and correcting the roundness of the ends of the pipes; fluid-driven cylinders (18a-18b) which act on corresponding sets of radial pins (20a-20b) for supporting the trucks; and transmission means (26a-26b) interposed between the fluid-driven cylinders (18a-18b) and the respective sets of radial pins (20a-20b) which are adapted to mechanically multiply the force applied by the cylinders to the pins. <IMAGE>