CHANGEABLE PRIORITY DEVICE FOR HEAVY EQUIPMENT

摘要

PURPOSE: A changeable priority device in a construction heavy equipment such as an excavator having more than two actuators operated in a complex way independently or simultaneously by receiving an amount of vent flow by one hydraulic pump is provided. CONSTITUTION: Control valves(12,13) are established for controlling the driving of at least two actuators in a vent line(11) of a hydraulic pressure pump(10). And a changeable orifice(17) is established to be switched to an orifice state(15) and to an orifice release state(16) so one actuator as to secure a priority function for another actuator by being switched when feeding a pilot signal pressure(Pi) to control the control valve(12) at a parallel line(14) and also at the vent line(11). Therefore, the loss of a pressure is prevented when driving an arm cylinder because the operation oil vented from the hydraulic pressure pump(10) is normally supplied to the arm cylinder or a revolving motor through a changeable orifice(17) converted to the orifice release state(16) arranged at a parallel line(14) branched and at the vent line(11).