Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Construction or agricultural-type vehicle
Reexamination Certificate
1999-03-12
2001-02-06
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Construction or agricultural-type vehicle
C091S361000
Reexamination Certificate
active
06185493
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to a method and apparatus for controlling the movement of a work implement of a work machine and, more particularly, to an apparatus and method that controls the movement of the work implement based on the work implement position and operator command.
BACKGROUND ART
Work machines such as wheel type loaders include work implements capable of being moved through a number of positions during a work cycle. Such implements typically include buckets, forks, and other material handling apparatus. The typical work cycle associated with a bucket includes sequentially positioning the bucket and associated lift arm in a digging position for filling the bucket with material, a carrying position, a raised position, and a dumping position for removing material from the bucket.
Control levers are mounted at the operator's station and are connected to an electrohydraulic circuit for moving the bucket and/or lift arms. The operator must manually move the control levers to open and close electrohydraulic valves that direct pressurized fluid to hydraulic cylinders which in turn cause the implement to move. For example, when the lift arms are to be raised, the operator moves the control lever associated with the lift arm hydraulic circuit to a position at which a hydraulic valve causes pressurized fluid to flow to the head end of a lift cylinder, thus causing the lift arms to rise. When the control lever returns to a neutral position, the hydraulic valve closes and pressurized fluid no longer flows to the lift cylinder.
In normal operation, the work implement is often abruptly started or brought to an abrupt stop after performing a desired work cycle function, which results in rapid changes in velocity and acceleration of the bucket and/or lift arm, machine, and operator. This can occur, for example, during a dumping operation when the bucket is moved to the end of its desired range of motion in a dumping position and the boom is quickly raised. This will impose excessive forces to the physical dump stops located on the boom.
These forces may damage the boom, as well as, damage the associated hydraulic circuitry that absorbs some of the shock that travels through the linkage assembly. This will likely increase maintenance and accelerated failure of the associated parts.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, an apparatus for controllably moving a work implement is disclosed. The work implement includes a boom and a bucket being attached thereto where the boom is actuated by a hydraulic lift cylinder and the bucket is actuated by a hydraulic tilt cylinder. An operator controlled joystick produces an operator command signal for controlling the movement of the work implement. Implement position sensors sense the elevational position of the boom and the pivotal position of the bucket, and responsively produce respective implement position signals. A controller receives the implement position and operator command signals, determines the instant position of the work implement, reduces the operator command signal as the boom is being raised and the bucket is being pivoted, and produces an electrical valve signal based on the reduced operator command signal. A valve assembly receives the electrical valve signal and controllably provides hydraulic fluid flow to the respective hydraulic cylinders in response to a magnitude of the electrical valve signal.
REFERENCES:
patent: 4037742 (1977-07-01), Gustafsson
patent: 4552503 (1985-11-01), Mouri et al.
patent: 4712376 (1987-12-01), Hadank et al.
patent: 4869635 (1989-09-01), Krahn
patent: 4942529 (1990-07-01), Avitan et al.
patent: 4964779 (1990-10-01), Sagaser
patent: 5188502 (1993-02-01), Tonsor et al.
patent: 5208753 (1993-05-01), Acuff
patent: 5245137 (1993-09-01), Bowman et al.
patent: 5613581 (1997-03-01), Fonkalsrud et al.
patent: 5701793 (1997-12-01), Gardner et al.
patent: 5807061 (1998-09-01), Donoghue et al.
patent: 5953977 (1999-09-01), Krishna et al.
Dietz Hans P.
Skinner Thomas G.
Caterpillar Inc.
Masterson David M.
Meyers Liza J.
Zanelli Michael J.
LandOfFree
Method and apparatus for controlling an implement of a work... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for controlling an implement of a work..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for controlling an implement of a work... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2612904