| 摘要 |
PURPOSE: A hydraulic jack is provided to warn leakage of oil from the hydraulic jack by generating a warning sound and to prevent an accident by alarming the leakage of the oil into a user. CONSTITUTION: A hydraulic jack comprises a rod(12) movably mounted on a cylinder(10); a supporting bar(14) fixed on an end portion of the rod; an oil reserving unit(20) containing oil to actuate the cylinder; a passage connecting a pumping space and the cylinder by being mounted on the pump; unidirectional valves(34a,34b) formed on the passage; a controller(36) extending or contracting volume of the pumping space; a pressure sensor(41) mounted on a lower portion of the cylinder; and a warning unit having an alarm(43) and a displayer(44). The oil contained in the oil-reserving unit is supplied into the cylinder through the check valves and the pumping space. The piston rod is moved up and down by the cylinder to lift material mounted on the supporting bar. Thereby, the hydraulic jack alarms leakage of the oil from the hydraulic jack by generating a warning sound through the alarm.
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