Abstract: An apparatus for restricting pivoting of a pivotal axle in a forklift. The forklift has an axle that is supported pivotally relative to a body frame. A damper is arranged between the body frame and the axle to permit and restrict pivoting of the axle. An electromagnetic valve locks the damper to restrict pivoting of the axle. The axle is free to pivot when the pivot angle of the axle relative to the body frame exceeds a predetermined reference angle. A controller refers to the pivot angle and other factors relating to vehicle stability when deciding whether to restrict pivoting of the axle.

Abstract: An assembly for mounting a sensor, which measures a running state of a vehicle, on the vehicle at a predetermined positional relationship to the vehicle. The assembly includes a control unit for controlling the vehicle based on a signal transmitted from the sensor and a circuit board. The assembly further includes a case to be fixed to the vehicle for housing the circuit board and a holding member for holding the sensor at an inclination relative to the circuit board. The holding member maintains the positional relationship between the sensor and the vehicle when the case is fixed to the vehicle.

Abstract: An industrial vehicle has a body frame and an axle, which supports wheels and is pivotally supported by the body frame. A potentiometer is supported on the body frame and is spaced apart from the pivot axis of the axle by a predetermined distance. The potentiometer detects the pivot angle of the axle. A link mechanism amplifies motion of axle pivot and converts the axle motion into rotational or linear motion. The link mechanism then actuates the potentiometer in accordance with the converted motion.

Abstract: An ultrasonic sensor detects whether a piston is at the lowest position. The sensor is not affected by the environment or damaged by contact with other objects. The sensor is located in the bottom of a mast cylinder, transmits ultrasonic waves to the bottom of a piston and receives ultrasonic waves reflected by the piston. The sensor then outputs electric signals based on the received ultrasonic waves. The ultrasonic sensor is electrically connected to a transmitter-receiver, which, in turn, is electrically connected to a controller. The transmitter-receiver includes an ultrasonic wave generator and sends ultrasonic wave transmitting signal having a predetermined frequency to the ultrasonic sensor based on control signals from the controller. The controller measures time from when it outputs the ultrasonic wave transmitting signal to when the sensor receives a reflected wave. The controller then compares the measured time with a threshold value thereby judging whether the piston is at the lowest position.

Abstract: An apparatus for controlling pivoting of a forklift rear axle. A hydraulic damper is arranged between a rear axle and a forklift body. The damper includes two oil chambers. The oil chambers are connected to a first passage and a second passage. A two-way switch valve is arranged between the oil chambers. The valve permits the flow of oil between the oil chambers and allows pivoting of the rear axle when opened. The valve restricts the flow of oil between the oil chambers and prohibits pivoting of the rear axle, thereby locking the rear axle when closed. When the rear axle is released from a locked state, the valve repeats a valve cycle, which includes opening and closing the valve, to regulate the amount of fluid that flows between the chambers. The valve is then kept in an opened state. This prevents shock that may be produced by sudden tilting of the body when the rear axle is released from a locked state.

Abstract: An apparatus for controlling pivoting the rear axle of a forklift. The forklift includes forks, which are lifted and lowered relative to a body frame. A locking mechanism, which includes a hydraulic damper and an electromagnetic valve, locks the rear axle to stabilize the body frame. A controller controls the locking mechanism to lock the rear axle when the fork height is at least as great as a predetermined height threshold value and the weight of a load on the fork is at least as great as a predetermined weight threshold value. The controller also controls the locking mechanism to lock the rear axle when the lateral acceleration is at least as great as a predetermined threshold value. Further, the controller changes the threshold value of the lateral acceleration in accordance with the fork height.

Abstract: An axle tilt control apparatus for forklifts is disclosed. The forklift includes a rear axle pivotally supported by a body frame and a front axle rigidly fixed to the body frame. A mast is supported at the front portion of the body frame to tilt forward and backward. Forks are supported by the mast to be lifted and lowered. The center of gravity of the forklift in the fore-and-aft direction approaches the front axle as the mast is tilted forward. Pivoting of the rear axle is restricted by the hydraulic cylinder when the height of the forks is higher than a predetermined height determination value and the weight of a load on the forks is heavier than a predetermined weight determination value to improve the vehicle's stability. The weight determination value increases as the mast is tilted forward. When a load on the forks is being unloaded, tilting of the rear axle is permitted regardless of the height of the forks and the weight of the load on the forks. Therefore, the rear axle is not unnecessarily locked.

Abstract: An indicating method and apparatus of cargo load condition of a forklift truck. In this method and apparatus weight and centroid position of the loaded cargo are calculated by a calculation control circuit based on loads applied to a lift mechanism and a tilt mechanism of the truck. The calculated weight and centroid position are displayed on two-dimensional coordinates illustrated on a displaying device in contrast with an overturn danger line which is determined forecasting the forward overturn of the truck. The load condition may be displayed in three-dimensional coordinates in relation to lift height of the cargo as well as the weight and the centroid position thereof.