| 摘要 |
<p>PURPOSE:To enable a plurality of composite control valves to be operated by only a single valve mechanism by a method wherein a logical valve is provided at the tail end of an unload circuit for a composite control valve on one side, the logical valve being controlled by a composite control valve on the other side, and the upstream side of the logical valve is connected to an actuator of the composite control valve on the one side. CONSTITUTION:The logical valve 27 is provided at the tail end of the unloading circuit for the composite circuit on one side, a spring chamber of the logical valve 27 is connected to a selector 23 of the composite control valve on the other side through a pilot passage 24, and the upstream side of the logical valve 27 is connected to the actuator 7 of the composite control valve on the other side. When the valve mechanism 22 is moved to a lower position, a hydraulic oil from a pump 5 flows to the head side of the actuator 7 through the valve mechanism 22 to move a piston 7A upward, and the oil on the rod side is discharged into a tank 15 through the valve mechanism 22. At this instant, the selector 23 is also brought to a lower position and the logical valve 27 interrupts the communication between a passage 26A and a passage 28. Accordingly, the hydraulic pressure from the pump 13 flows to the head side of the actuator 7 through a check valve 29 and the actuator 7 is supplied with the joint flow of the hydraulic oil from the pump 5 and that from the pump 13.</p> |
