ON-OFF HIGH PRESSURE CUTOFF CONTROL SYSTEM

摘要

PURPOSE: To enable operation mode to be selectable by arranging a high pressure cutoff valve in a pilot passage connecting an output port to an actuating cylinder chamber of an actuator and arranging an on-off valve in another pilot passage connecting the output port to one side of the high pressure cutoff valve. ;CONSTITUTION: A hydraulic apparatus 10 has a plurality of hydraulic pumps 11, 12 connected to a tank 13 respectively. The hydraulic pumps 11, 12 comprise a plurality of output ports 15, 16, rotary swash plates 17, 18, actuators 19, 20 having actuating cylinder chambers 21, 22; 23, 24, connected thereto, and first pilot passages 27, 28 connecting the output ports 15, 16 to the actuating cylinder chambers 22, 24 respectively. In this case, high pressure cutoff valves 39, 40 are arranged in the first pilot passages 27, 28. On the other hand, a second pilot passage 45 is arranged for connecting the output ports 15, 16 to one side of the high pressure cutoff valves 39, 40. An on-off valve 47 is arranged in the second pilot passage 45.;COPYRIGHT: (C)1993,JPO