Method and equipment for handling pipe mounted carriage

Apparatus for supporting a welding machine carriage in working relationship to a pipe to be welded, said apparatus being coupled with an overhead support and comprising:

• first and second extendable support legs, each of said legs having two pipe engaging feet and being movable relative to said carriage over a rectilinear path between extended and retracted positions;
• track means for mounting said support legs for reciprocal movement relative to said carriage;
• first and second cable means coupled with said overhead support and with said first and second support legs, respectively;
• first and second sheave means disposed on said carriage for receiving said first and second cable means, said first and second sheave means being disposed below the point of attachment of said cable means to said support legs;
• and
• first and second power cylinder means coupled with said carriage and with said first and second support legs, respectively, said first and second cable means respectively including cables of sufficient lengths relative to the distance between said extended and retracted positions of the corresponding support legs whereby the cables are slack and the entire weight of the carriage is supported on the pipe by the legs when the latter are in their extended positions and the entire weight of the carriage is supported by the cables with the legs clear of the pipe when the legs are in their retracted positions, and whereby retraction of said legs results in simultaneous upward movement of said carriage.

Apparatus for raising and lowering a welding machine carriage through a variable working distance between a pipe to be welded and an overhead support, said apparatus comprising:

• extendable leg means;
• means mounting the leg means on the carriage for up and down movement relative to the carriage along a path of travel for engagement of the leg means against the surface of the pipe;
• power cylinder means operably coupled with the carriage and the leg means for moving the latter along said path, said power cylinder means having a predetermined stroke;
• and cable means operably coupled with the leg means and adapted to be coupled with said overhead support, the cable being of sufficient length relative to the stroke of the power cylinder means and the variable working distance whereby the cable is slack and the entire weight of the carriage is supported by the leg means engaging the pipe at one end of the stroke of the power cylinder means and the leg means is retracted from the pipe and the entire weight of the carriage is supported by the cable at the opposite end of said stroke.