| 摘要 |
<p>A control valve for hydraulically controlling the lifting operations of a working machine such as rotary, plow, etc., connected to an agricultural power machine such as tractor, said control valve comprising a check valve disposed between a change-over valve and a cylinder, a passage for introducing the cylinder holding pressure into the pilot chamber of said check valve, and a passage connecting and disconnecting means whereby when the change-over valve is at its neutral or elevating position, the cylinder holding pressure is introduced into said pilot chamber through said passage, and when the change-over valve is at its dropping position, said passage is shut off and said pilot chamber is connected to the tank.</p> |
