US Patent 6893189 Pipelayer

A pipelayer is provided which is capable of effectively transporting pipes or the like and stably carrying out load hoisting operation on a slope. The pipelayer comprises: an undercarriage; an upper revolving superstructure mounted on the undercarriage so as to turn around freely upon the undercarriage; a boom supported by the upper revolving superstructure so as to be freely raised and lowered; a pulley block attached to the boom through a universal joint; a hoist mounted on the upper revolving superstructure; a hoist hook hung by a wire rope that is paid out from the hoist and wound around the pulley block.