US Patent 7654593 Safety hook for patient lift

A safety hook for mounting on the extremity of a spreader bar of a patient lift is secured to a base member that is connected to or integral with the spreader bar. A load-bearing hook member is pivotally suspended from the base member to allow the hook member to move in the plane of the hook member between an open position and a closed position in which the free end of the hook member engages the base member at an engagement point. The hook member is shaped such that it is urged to the closed position when a downward load is applied to it, and that it is urged to the open position when an upward load is applied to it. Under normal circumstances the safety hook closes automatically because of the weight of the load.