Mobile crane hydraulic ground support - has ram valve shut by differential piston with larger face towards ram

摘要

The hydraulic jacking system is designed for the outriggers or pendulum-mounted axles of mobile cranes or excavators. It has one or more rams pressurised over a predetermined low pressure range by a control valve, or is hydraulically lockable by this valve. A valve (2) is mounted directly on the ram (34) and has a plug (4), urged to open position by a spring and shut by a differential piston (6). The larger working face (15) of the piston faces towards the ram. Pref. the valve has separate inlet and outlet ducts, a connecting duct branching-off from the inlet to the outlet duct. The piston slides sealingly between the inlet and outlet ducts. PS.