EMERGENCY SHUTOFF VALVE OF LIFT DEVICE

PROBLEM TO BE SOLVED: To provide an emergency shutoff valve having an adjusting range wider than a conventional emergency shutoff valve by solving a problem of being narrow in the adjusting range in the conventional emergency shutoff valve while conventionally having a technology for interposing the emergency shutoff valve in the hydraulic fluid outflow side at lowering time for preventing a lift device from carelessly falling by oil leakage when a hydraulic hose is damaged in the lift device using a hydraulic cylinder as a driving source. SOLUTION: When differential pressure ΔP between inflow side pressure P1 and outflow side pressure P2 becomes large, an operation valve 5 is moved in the cutoff direction against a compression spring 8, and a passage 7 is cut off by allowing an inner peripheral side end part 5a to abut to a diametrally expansive base part 6a of a fixed valve 6. Since working pressure (the differential pressure ΔP for cutting off the passage 7) is adjusted by changing an inner diameter of the inner peripheral side end part 5a or a tip angle θ of the diametrally expansive base part 6a, the working pressure is adjusted over a range wider than a conventional rotary adjusting mechanism.