A method for controlling the hydraulic operation of mining machines in the event of a pressure supply reduction failure has a separate constant hydraulic pressure source.

摘要

An operating cylinder (11) is hydraulically controlled by valves (12,13) from a fluid pressure source (20) and a further valve (14) operates a water spray system. All the valves are controlled by pre-control electromagnetic (16) valves (15) connected to a constant pressure source (17). Hydraulic pressure is generated by a pump (23) through a back pressure valve (22) to the operating valves and the reserve fluid reservoir (25) which is pressurised by a gas source (26). When the hydraulic pressure fails the back pressure valve closes and constant pressure is supplied from the reserve system.