| 摘要 |
PROBLEM TO BE SOLVED: To relax an impact occurring at the time of actuation of a fall prevention valve. SOLUTION: A safety valve device 14 is for a hydraulic elevator in which a cage is ascended and descended with pressure oil supplied to or discharged from a hydraulic cylinder, which is caused by the control of a main valve. The safety valve device includes the fall prevention valve 31 disposed in a main pipe line KM between the hydraulic cylinder and the main valve to intercept the stream of the pressure oil discharged from the hydraulic cylinder at the time of occurrence of abnormality, and a differential pressure detection auxiliary valve 33 that detects as a differential pressureΔP a pressure drop which is caused by the fall prevention valve 31 when the fall prevention valve 31 is actuated, and relaxes the intercepting characteristic of the stream of the pressure oil by the fall prevention valve 31. COPYRIGHT: (C)2008,JPO&INPIT
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