Lifting machine with parallelogram linkage - has double-acting hydraulic actuator with supply and drain valves

摘要

The handling machine for loads has a parallelogram linkage. The load is held on a link end by a grab. The linkage is actuated by a vertical linear hydraulic actuator for ensuring lifting movement. One end (18) of the linear actuator (15) is connected directly to pressurised fluid source (21). Pressurised fluid is supplied or drained from the other end (19) of this actuator for moving the load in a vertical direction. A valve (20) controls fluid supply for lifting and lowering and is controlled by a drainage valve.