| 摘要 |
PURPOSE:To prevent the driving of a prescribed actuator from being affected by the changeover valve operation of another actuator, by using a pilot valve interlocked with a prescribed changeover valve, to control a check valve for another changeover valve. CONSTITUTION:Since pilot pressure acts to the pilot chamber 72 of a pilot valve 71 through a shuttle valve 70 and shifts the pilot valve to a position B, pumped liquid pressure from a main passage 36 acts to the spring chamber 74 of a check valve 73 so that the primary port 78 and spring chamber 74 of the check valve have the same pressure and a poppet 79 is put in contact with a valve seat 77 by the force of a spring 75 and disconnects the primary port and secondary port 79 from each other. In that state, liquid discharged from a pump does not flow into a working cylinder 44 even if the lever 88 of pilot operating valve 46 is turned down rightward or leftward to conduct pilot pressure into the pilot chamber 59 or 60 of a changeover valve 38 to shift it to a position A or B. |
