Motors: expansible chamber type – Working member position feedback to motive fluid control – Valve locking means
Patent
1981-11-20
1984-09-04
Michalsky, Gerald A.
Motors: expansible chamber type
Working member position feedback to motive fluid control
Valve locking means
91522, 91529, 91530, 13759615, 1376362, F15B 1308
Patent
active
044690070
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention is directed to a single lever pilot control system and more particularly to a mechanism to maintain a main control valve in an actuated position while freeing the single lever pilot control to return to a neutral position.
2. Background Art
In many single lever control systems known today, a single lever pilot control can be moved along one axis to an actuated position to actuate a first actuator and along a different axis to actuate another actuator while the lever is held in the first actuated position. Some such systems also have a detent mechanism to hold the single lever pilot control in the first actuated position and a release mechanism to automatically release or override the detent mechanism in response to the first actuator reaching a predetermined position. One of the problems encountered with the latter systems occurs when the pilot control is manually moved along the different axis while being held in the first actuated position by the detent mechanism. When the detent mechanism suddenly automatically releases, the pilot control is sometimes inadvertently held in the first actuated position temporarily by the operator and thereby cause the actuator to overrun the desired stop position.
DISCLOSURE OF THE INVENTION
In one aspect of the invention, a pilot operated system has first and second pilot operated control valves each movable between a neutral position and first and second actuated positions. The system has a single lever pilot control valve movable between a neutral position and a plurality of other positions for controlling the actuation of the first and second pilot operated control valves. A means holds the first pilot operated control valve at the first actuated position while freeing the single lever pilot control valve to return to the neutral position.
This invention solves the problem of the actuator not stopping at the desired position caused by the operator inadvertently holding the single lever valve in an actuated position once the detent mechanism is released. The mechanism of this invention frees the single lever control to return to the neutral position after actuating the first pilot operated control valve to move the first actuator. Consequently, simultaneous actuation of the second actuator will not result in an override of the desired stop position of the first actuator upon automatic release of the first pilot operated control valve. This results in more precise control of the first actuator's stop position.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a partial schematic and diagrammatic representation of an embodiment of the present invention.
FIG. 2 is a diagrammatic view II--II taken from FIG. 1 to better illustrate a portion of the single lever control mechanism.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring now to FIG. 1, a pilot operated control system is generally indicated by reference numeral 10 and includes a source of pressurized fluid, such as, a pump 12 receiving fluid from a tank or reservoir 14 and first and second actuators 16, 18 connected to the pump 12 and each movable between first and second positions. As is well known in the art, first and second pilot operated control valves 20, 22 controllably direct fluid from the pump 12 to the first and second actuators 16, 18. The first and second control valves 20, 22 are movable between a spring biased, neutral position and first and second actuated positions by directing pressurized fluid to each end 23, 24, and 23', 24' respectively in a conventional manner. Since both control valves 20, 22 operate in the same manner, reference will be directed only to the first control valve 20 and the first actuator 16. At the neutral position, as shown, the flow from the pump 12 is blocked from the actuator 16 and is free to pass to the tank 14 through the control valves 20, 22 since, as shown, they are both in the neutral position. At the first actuated position of the first control valve 20, the flow from the pump 12 is directed to a head end 25 of actuato
REFERENCES:
patent: 3823647 (1974-07-01), Campbell et al.
patent: 3883783 (1975-05-01), Fuzzell
patent: 4011959 (1977-03-01), Papasideris
Burrows J. W.
Caterpillar Tractor Co.
Michalsky Gerald A.
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