Fluid handling – Systems – Line condition change responsive release of valve
Patent
1980-10-17
1982-06-29
Cohan, Alan
Fluid handling
Systems
Line condition change responsive release of valve
13762569, F16K 1107
Patent
active
043368271
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates generally to a valve for use in a hydraulic system and more particularly to a latching mechanism that is integral with the valve for hydraulically holding a spool in the actuated position.
2. Background Art
Some valves use detents that act against the spool and are hydraulically held in position by the system pressure. Others use a plunger that responds to system pressure to act against a series of ball detents to hold the spool in an actuated position. These all require several additional pieces to perform their function plus require various external lines to route system pressure. Still other valves also use detents that are engaged manually by shifting the spool and released in response to a pressure reaching a predetermined level or the work piece reaching a predetermined position. These likewise require external lines to initiate operation.
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 valve has a housing with a bore and an inlet and outlet port in communication with the bore. A spool is slideably disposed in the bore and moveable between a first position at which the inlet port is blocked from the outlet port and a second position at which the inlet port is in communication with the outlet port. An actuation means controls movement of the spool between the first and second positions. A valve means hydraulically latches the actuation means at the second position in response to the actuation means being moved to the second position. The valve means is integral with the actuation means.
BRIEF DESCRIPTION OF THE DRAWINGS
The FIGURE is a cross-sectional view of a valve encompassing an embodiment of the present invention.
Best Mode for Carrying Out the Invention
Referring now to the FIGURE, a fluid system is generally indicated by reference numeral 10 and includes a pump 12, a valve 14, and a fluid unit, such as a clutch 16, each respectfully interconnected to the valve 14 through conduits 18,20. The pump is driven by an engine, not shown, while the clutch 16 is used, for example to engage a power take off (PTO) on a tractor, not shown.
The control valve 14 includes a housing 22 defining a bore 24. An inlet port 26 is connected to conduit 18 and communicates with bore 24. An outlet port 28 is connected to conduit 20 and communicates with the bore 24.
A spool 30 is slideably disposed in bore 24 and has a first bore 32 at one end portion of the spool and a second bore 34 on the other end portion of the spool. The first and second bores 32,34 are connected by a third through bore 36. The spool 30 is moveable between a first position at which the inlet port 26 is blocked from communication with the outlet port 28 and a second position at which the inlet port 26 is in communication with the outlet port 28.
A plug 38 is positioned in one end 39 of the bore 24 of the housing 22 and is secured by a snap ring 34. The plug 38 has an annular end portion 40 which slideably and sealingly receives the first bore 32 of spool 30 to produce a pressure responsive surface 42. Pressure responsive surface 42 is in communication with outlet port 28 through a feedback passage 44 to provide a feedback signal to spool 30. A spring 46 is positioned between plug 38 and spool 30 to bias spool 30 to the first position, as shown. An actuation means 47 controllably moves the spool 30 between the first and second positions.
A valve means 48 for hydraulically latching the actuation means 47 at the second position in response to the actuation means 47 being moved to the second position is axially positioned in the bore 24 relative to the spool 30. A passage 50 communicates inlet port 26 with the valve means 48 and an exhaust passage 51 communicates an exhaust port 52 with the valve means 48. The exhaust port 52 is connected to a tank 54 through a conduit 56. Valve means 48 includes a first member 58 secured in the bore 24 and defines a fluid chamber 59 at ano
REFERENCES:
patent: 2689585 (1954-09-01), Presnell
patent: 2837117 (1955-06-01), Ruhl
patent: 2864402 (1958-12-01), Presnell
patent: 2874720 (1959-02-01), Vahs
patent: 3247768 (1966-04-01), Tennis
patent: 3511276 (1970-05-01), Jessen
patent: 3568717 (1971-03-01), Plate
patent: 3790125 (1974-02-01), Swatty
patent: 3866880 (1975-02-01), Schexnayder
Burrows J. W.
Caterpillar Tractor Co.
Cohan Alan
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