| 摘要 |
PURPOSE:To eliminate the necessity for pilot pump and simplify circuit constitution, by acting pressure of an operating pump to a control valve through a logic valve. CONSTITUTION:When a selector valve 10 is placed to a neutral position, a rear chamber 6a is connected to a tank 4, and pressure oil from a pump 2 is discharged to the tank 4 in an unloaded state. Now the selector valve 10 is switched to a selective position 10b, then a pipe line 9 is disconnected from the tank 4, and the rear chamber 6a of a logic valve 6 is connected to a pilot motor 12b through circuits 9, 11b. Here a check valve 7 is returned from the upper to the lower position to close a bypass passage 5 communicated to the tank 4. Then pressure of the pump 2 rises, also pressure of the rear chamber 6a rises. Pressure in the rear chamber 6a acts upon the motor 12b, and a control valve 1 is switched to a working position 1c, then pressure oil from the pump 2 is fed to rotate a motor 3. |
