Patent ID: 6131918
Filing Date: 2000-10-17
Classification: B60G,B66F,F16F,Y10S

Abstract:
An apparatus for controlling tilting of an axle, wherein the middle of the axle is pivotally supported by the frame of an industrial vehicle such that the axle is tiltable relative to the frame, the apparatus comprising:a pair of hydraulic cylinders located near the ends of the axle, each cylinder being connected to both the axle and the frame, wherein each cylinder includes a piston and a pair of fluid chambers defined by the piston, wherein each piston is movable when fluid is permitted to enter and exit the corresponding fluid chambers, and wherein each piston is locked against movement when fluid is not permitted to enter and exit the corresponding fluid chambers, wherein the axle is tiltable when the pistons in the cylinders are movable, and wherein the axle cannot tilt when the piston of at least one of the cylinders is locked;a pair of valves, each corresponding to one of the cylinders, wherein each valve selectively permits and prohibits flow of fluid into and from the fluid chambers of the corresponding cylinder;a controller for controlling the valves, wherein the controller controls only one of the valves at a time such that the cylinder corresponding to a currently controlled valve is regulated to control tilting of the axle;a sensor for detecting the fluid pressure in at least one of the fluid chambers of each cylinder; andmeans for determining whether the cylinder corresponding to the currently controlled valve is functioning normally based on the fluid pressure detected by a corresponding one of the sensors being above a predetermined level of pressure, wherein, when the determining means determines that the cylinder corresponding to the currently controlled valve is malfunctioning, the controller controls the other valve such that the other cylinder is regulated to independently control the tilting of the axle irrespective of the malfunctioning valve.