Fluid control system with float capability

Details Fluid control system with float capability Fluid control system with float capability

1999-03-08

2001-02-13

Lopez, F. Daniel (Department: 3745)

Motors: expansible chamber type

With motive fluid valve

Independent control of bypass between opposed working chambers

C091S447000

Reexamination Certificate

active

06186044

ABSTRACT:

TECHNICAL FIELD
This invention relates generally to a fluid control system for a lift actuator for a bucket of a loader or the like, and more particularly, to a fluid control system having a valve arrangement providing a simple, easy to use float capability.
BACKGROUND ART
Fluid control systems including a float capability, that is, the ability for fluid to move between one actuating chamber of a double acting actuator such as a lift actuator or the like and another actuating chamber thereof under equalized pressure conditions to provide a ground following capability, are well known. Typically however, the known systems utilize a spool type directional control valve for the actuator having added float position, which adds complexity, cost and leakage potential. It has also been problematic to provide a float capability in systems having check valves between the actuator and the directional control valve, as the checks can interfere with the free flow of fluid to and from the actuating chambers.
Accordingly, 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, a fluid control system providing a simple, easy to use float capability for a double-acting actuator having a first actuating chamber, a second actuating chamber, and an actuating member such as a piston rod disposed for movement therebetween, is disclosed. The system includes a first pilot signal operated check valve connected to the first actuating chamber and operable for controlling fluid flow thereto and therefrom, a second pilot signal operated check valve connected to the second actuating chamber and operable for controlling fluid flow thereto and therefrom, and a pilot signal operated directional control valve. The directional control valve has a first port connected to the first pilot signal operated check valve, a second port connected to the second pilot signal operated check valve, a tank port and a pump port. The directional control valve and the check valves are cooperatively operable under a first pilot signal condition to allow fluid flow from the first actuating chamber to the tank port, and fluid flow from the pump port to the second actuating chamber, and the directional control valve and the check valves are cooperatively operable under a second pilot signal condition to allow fluid flow between the actuating chambers to allow pressure conditions therein to equalize such that the actuating member can float. The system importantly further includes a valve arrangement connected to the check valves and the directional control valve for producing the first and second pilot signal conditions thereon, including changing the first pilot signal condition to the second pilot signal condition when the first pilot signal condition reaches a predetermined signal strength, to initiate the float capability.


REFERENCES:
patent: 3381587 (1968-05-01), Parquet
patent: 3965587 (1976-06-01), Johns
patent: 4093002 (1978-06-01), Tardy
patent: 4204459 (1980-05-01), Johnson
patent: 4958553 (1990-09-01), Ueno
patent: 5331882 (1994-07-01), Miller

Affiliated with

Also associated with

Rating

Fluid control system with float capability does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fluid control system with float capability, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluid control system with float capability will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2574478