| 摘要 |
PROBLEM TO BE SOLVED: To provide a lifting hydraulic drive mechanism for stopping a hydraulic motor when the pressure of operating oil drops during driving a cargo lift with the hydraulic motor arranged in a closed hydraulic circuit. SOLUTION: The lifting hydraulic drive mechanism comprises the hydraulic motor 2 for driving the drum of a winch device which introduces operating oil from a hydraulic pump 1 to lift up and down a container, the closed hydraulic circuit 3 having a counterbalance valve 13 for circulating the operating oil to the pump and the motor to operate back pressure during lifting-down operation of the container, an oil circuit 5 for circulating the operating oil between the closed hydraulic circuit and an oil tank 4, a brake operating circuit 7 for supplying the operating oil from the oil circuit to a brake part 6 of the hydraulic motor, and a pressure sensor 51 provided in an oil intake pipe 23 for detecting hydraulic pressure in the closed hydraulic circuit. When inputting pressure detected by the pressure sensor, if it is lower than a set value, a control part operates a solenoid on-off valve 42 to supply the operating oil to the brake part and constrain the rotation of the hydraulic motor. COPYRIGHT: (C)2007,JPO&INPIT
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