US Patent 8042626 Gripping tool

A gripping tool includes a body assembly and gripping assembly with a grip surface adapted to move from a retracted position to an engaged position to radially engage a work piece in response to relative axial displacement. A linkage is provided to act between the body assembly and the gripping assembly which, upon relative rotation in at least one direction, of the body relative to the grip surface results in relative axial displacement of the grip surface to activate the gripping elements. This tool was developed for use on drilling and service rigs having top drives, and supports rapid engagement and release, hoisting, pushing, and rotating.