| 摘要 |
PROBLEM TO BE SOLVED: To achieve a low-cost lifting device by a fluid control while the impact is inhibited during lowering operation. SOLUTION: A pump 253 and a cylinder 231 are connected in a flow path while the cylinder 231 and a reserver 254 are connected in the flow path through a constant flow valve 258 flowing a certain flow amount of the fluid. The pump and a valve control part 260 equilibrate the flow amount of fluid discharged by the pump 253 and the flow amount of the fluid returning to the reserver 254 through the constant flow valve 258 when a table section 101 is lowered, and then the amount of the fluid discharged by the pump 253 is made smaller than the constant flow amount in order to reduce the amount of the fluid stored in the cylinder 231. An expensive proportional control valve is not used. COPYRIGHT: (C)2009,JPO&INPIT
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