HYDRAULIC CRANE MECHANISM OPERABLE TO PROVIDE ENLARGED PARALLEL MOVEMENT

摘要

A hydraulic crane includes a pair of boom arms and a pair of swing arms pivotally connected in association with a pair of auxiliary arms and arranged in the form of a pantograph. Substantially horizontal or vertical displacement of one of the pivotal connections by hydraulic piston devices will effect correspondingly substantially horizontal and vertical displacement respectively, but to a larger degree, of a swing means from which a cargo load may be suspended or to which an excavating shovel or the like may be attached.