Hoisting apparatus having improved clamping means

摘要

A hoisting apparatus includes a hoisting shank slidably engaged with a yoke, the yoke having parallelogram linkages which carry a pair of gripping jaws. The shank is connected with the jaws to spread them apart as the shank moves downwardly with respect to the yoke, and is provided with locking mechanism normally connecting the shank directly to the yoke. A work-engaging mechanism automatically releases the locking mechanism and allows the shank to shift upwardly with respect to the yoke and cause the jaws to grip a load.