| 摘要 |
<p>A control valve adapted for use in working machines for hydraulically controlling the lifting movements of the working machine such as a rotary or plow connected to a power machine, said control valve comprising essentially a change-over valve for connecting or shutting off the cylinder port to or from the pump port or tank port by a spool operation, and a compensator for guiding cylinder port pressure into an oil chamber of a plunger on the spring loaded side for bypassing the pump discharge oil opposedly to the pump pressure, and characterized by provision of a passage for connecting the oil chamber of the compensator on said spring loaded side into the tank port or cylinder port through said change-over valve, whereby when said change-over valve is at its neutral or dropping position, said oil chamber is communicated with the tank port, and when said valve is at its elevating position, said oil chamber is communicated with the cylinder port.</p> |
