摘要 |
A branch line branching from midway of a hydraulic conduit or each of actuator side oil passages to connect a bottom side oil chamber of a hoist cylinder to a tank is provided to the hydraulic conduit or each of the actuator side oil passages. A manual operation valve for variably adjusting the flow rate in accordance with the operation of a lever handle is provided in the branch line. Maintenance work is performed with an engine stopped in this state. Subsequently, when a vessel is lowered onto a vehicle body, hydraulic oil can be discharged through the branch line from the bottom side oil chamber of the hoist cylinder to the tank by opening the manual operation valve, so that the hoist cylinder can be automatically contracted.
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