INDUSTRIAL VEHICLE

摘要

A hydraulic mechanism is mounted on a forklift. The hydraulic mechanism has a control valve and a pressure compensation circuit for compensating pressure within the hydraulic mechanism. The pressure compensation circuit has a relief pressure valve and an unloading valve for releasing pressure within the pressure compensation circuit to a discharge oil passage. Upon instructed to perform cargo handling operation, the unloading valve is switched to an open state, and the relief pressure valve is thereby actuated, so that rapid increase of pressure within the circuit is avoided. Further, the unloading valve is switched to an open state, and the pressure within the hydraulic mechanism is thereby released to the discharge oil passage, so that the cargo handling operation by the tilt cylinder and the lift cylinder is restricted.

主权项

1. An industrial vehicle comprising:
an engine; a hydraulic pump driven by the engine; a hydraulic actuating device actuated by hydraulic oil; a connection oil passage connecting the hydraulic pump and the hydraulic actuating device; a supply oil passage through which hydraulic oil to be supplied to the hydraulic actuating device passes; a discharge oil passage through which hydraulic oil to be discharged to an oil tank passes; an unloading valve connecting the supply oil passage and the discharge oil passage; a relief pressure valve connected to the supply oil passage and actuated by pressure of the hydraulic oil passing through the supply oil passage; a timer circuit unit connected to the supply oil passage and opening the supply oil passage when a certain time period has elapsed; and a control unit controlling a state of the unloading valve between an open state and a closed state, wherein the control unit switches the state of the unloading valve to an open state when a load is applied to the engine in a state where operation of the hydraulic actuating device is allowed and switches the state of the unloading valve to an open state while operation of the hydraulic actuating device is restricted.