| 摘要 |
PROBLEM TO BE SOLVED: To efficiently operate a hydraulic pump by controlling the operation of the pump by a pressure switch operated by the pressure difference between the hydraulic pressure of a hydraulic pressure passage and the hydraulic pressure of a power cylinder. SOLUTION: A piston 15 is inserted into a cylinder 14 to partition the inner part of the cylinder 14 into a first pressure chamber 16 and a second pressure chamber 17, the hydraulic pressure within a hydraulic pressure passage on the downstream side from a check valve is guided into the first pressure chamber 16, and the hydraulic pressure within one hydraulic fluid chamber or the other hydraulic fluid chamber is guided into the second pressure chamber 17. Limit switches 19, 20 operable by the end parts 18a, 18b of a piston rod 18 integrated to the piston 15 are provided on both end sides of the cylinder 14 in opposition to the end parts 18a, 18b extended through both the ends of the piston 14 so as to seal them. A switch signal from a pressure switch 11 is guided to an electromagnetic clutch through a control device, and this electromagnetic clutch is controlled, whereby the operation of a hydraulic pump is controlled. |
