VERTICAL MOTION COMPENSATED CRANE APPARATUS

摘要

VERTICAL MOTION COMPENSATED CRANE APPARATUS Disclosed is a crane employing a fluid cylinder and a piston assembly secured to the crane boom and operatively interconnected with the cable between the boom sheave and the load hook to vary the vertical distance between the boom sheave and the load hook in response to relative vertical movement between the crane boom and the platform to or from which a load is to be transferred. Sensors which generate a signal in response to vertical movement are associated with each platform which is movable with respect to a fixed horizontal position. Signals from the sensors are used to control the position of the piston in the cylinder and thereby vary the vertical separation between the hook and the boom in relation to relative vertical movement between the boom and the landing platform.