Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Construction or agricultural-type vehicle
Reexamination Certificate
1998-12-11
2001-07-03
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Construction or agricultural-type vehicle
C701S001000, C701S049000, C172S004500, C172S009000, C037S347000, C037S348000
Reexamination Certificate
active
06256566
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to industrial vehicles such as forklifts, and more specifically, to a lifting mechanism controller and an industrial vehicle having the lifting mechanism controller.
Japanese Unexamined Patent Publication Nos. 7-2496 and 7-61792 describe a controller that controls the fork and the mast of a forklift, independent of manipulation by the driver. The controller stores a map for controlling movements of the fork and mast. The Publications describe a position sensor for detecting the fork position and the mast angle and a state sensor for detecting the operating state of the vehicle. The controller sets a target value corresponding to a target fork height (or mast angle) based on a detection value of the state sensor and the map. When the position sensor detects a value corresponding to the target value, the controller stops the movement of the fork (or mast).
The installed position of the fork, mast and the position sensor with respect to a vehicle body varies in each vehicle. As a result, for a given value detected by the position sensor, the actual position of the fork and mast varies from one vehicle to another. In the prior art, the values corresponding to the target position of the fork and mast are stored in a map in advance. However, the stored data is shared by various vehicles and this lowers the precision of controlling the target position of the fork and mast.
This may cause problems when high precision is required in limiting the movement of the fork and mast. Therefore, there is a need for a controller that precisely controls the position of the fork and mast in consideration of the various installed positions of the fork, mast and sensor.
SUMMARY OF THE INVENTION
A first objective of the present invention is to provide a controller that controls the lifting mechanism of industrial vehicles. A second objective of the present invention is to provide a lifting mechanism controller that can be shared among various types of industrial vehicles.
To achieve the above objectives, the industrial vehicle of the present invention includes a load lifting mechanism and a detector for detecting the position of the lifting mechanism with respect to the vehicle. The detector outputs a signal indicating the current position. The industrial vehicle further includes a storage device for storing function information. The function information represents a relationship between a limit position of the lifting mechanism and a parameter that concerns the current operating conditions. The industrial vehicle further includes a controller for applying the function information to limit the movement of the lift mechanism depending on the value of the parameter. The controller is calibrated in each individual vehicle.
The present invention also provides a method for initializing a controller for an industrial vehicle. The method includes moving a lift mechanism on the vehicle to a known position and reading a reference value. The reference value is a signal from a sensor for detecting the position of the lift mechanism. The method further includes preparing function information for defining a relationship between a limit position of the lift mechanism and a parameter. The parameter concerns the operating conditions of the vehicle. The method further includes storing the function information for later use by a controller for controlling the limit position during operation of the vehicle.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
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patent: 4768636 (1988-09-01), Ito et al.
patent: 5462122 (1995-10-01), Yamamoto et al.
patent: 5487428 (1996-01-01), Yamamoto et al.
patent: 5555942 (1996-09-01), Matsushita et al.
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patent: 63-196500 (1988-08-01), None
patent: 7-242398 (1995-09-01), None
Kamiya Toshikazu
Maki Kunio
Arthur Gertrude
Cuchlinski Jr. William A.
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan , LLP
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