초록 ▼

A tilt control valve controls the flow of hydraulic oil to actuate the tilt cylinders of a forklift mast. The tilt control valve is switched between two positions by the forklift operator by means of a tilt lever. When at one position, the tilt control valve stops flow of oil to the tilt cylinders,

A tilt control valve controls the flow of hydraulic oil to actuate the tilt cylinders of a forklift mast. The tilt control valve is switched between two positions by the forklift operator by means of a tilt lever. When at one position, the tilt control valve stops flow of oil to the tilt cylinders, thereby prohibiting tilting of the mast. When at the other position, the tilt control valve permits oil flow to the tilt cylinders, thereby allowing tilting of the mast. A control valve is located between the tilt cylinders and the tilt control valve. A seat switch detects whether or not the operator is sitting on the seat. A CPU permits the operator to continue to operate the tilt cylinders to tilt the mast when out of the seat for a brief period. However, after the brief period, the CPU closes the control valve to prevent movement of the mast unless the operator has returned to the seat.When the mast reaches a predetermined maximum acceptable tilt angle, the CPU also closes the control valve, thereby prohibiting motion of the tilt cylinders.

대표청구항 ▼

[ What is claimed is:] [1.] A tilt cylinder controlling apparatus for an industrial vehicle, wherein the industrial vehicle includes a mast tiltally supported on a body frame, a carrier supported by the mast for carrying a load, a tilt cylinder for tilting the mast and a cab for an operator, the app

[ What is claimed is:] [1.] A tilt cylinder controlling apparatus for an industrial vehicle, wherein the industrial vehicle includes a mast tiltally supported on a body frame, a carrier supported by the mast for carrying a load, a tilt cylinder for tilting the mast and a cab for an operator, the apparatus comprising:a tilt valve that controls a supply of fluid to the tilt cylinder to actuate the tilt cylinder, wherein the tilt valve is switched between a first position for preventing fluid from entering the tilt cylinder to prohibit tilting of the mast and a second position for permitting fluid to enter the tilt cylinder to cause tilting of the mast;a handle for manually controlling the tilt valve;a fluid passage located between the tilt cylinder and the tilt valve;a control valve located in the fluid passage, wherein the control valve controls the flow of fluid in the fluid passage and thus selectively prohibits tilting motion of the mast;a first detector that detects whether an operator is at a predetermined operating position in the cab;a second detector that detects whether the tilt valve is moved to the second position by the handle; anda controller for actuating the control valve, wherein the controller judges whether to close the control valve to prohibit movement of the tilt cylinder, and the controller closes the control valve if the state of the first detector indicates that the operator has not occupied the predetermined operating position for a predetermined time period, wherein the predetermined time period is selected so that the operator may briefly move from the predetermined operating position without affecting the control valve.