US3943968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combination lock and relief valve for hydraulic systems
Assignee: Parker Hannifin Corp
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Filing: 1975-01-06
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Granted: 1976-03-16
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Expires: 1995-01-06
Abstract
Abstract A combination lock and relief valve in which a single valve poppet provides both functions. The combination valve is so arranged that the opening pressure of the poppet as a relief valve is independent of system pressure and remains constant regardless of system pressure variations. Moreover, when the poppet opens as a relief valve while the system pressure is on, the differential pressure across the poppet is relatively small whereby to minimize or eliminate erosion of the valve seat as occurs more readily when relief valve poppets are opened with high pressure differentials thereacross.
Inventors
- 👤 Ernest Treichler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:58
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/01; B; B64; B64C; B64C13/00; B64C13/24; B64C13/38; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7771; Y10T137/7781; Y10T137/7782; Y10T137/7835
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
243 words
A combination lock and relief valve comprising a housing having a valve chamber, a lock cylinder and a relief cylinder, a lock piston dividing the lock cylinder into first and second lock chambers, a relief piston dividing the relief cylinder into first and second relief chambers, said first lock chamber communicating with said valve chamber, a valve poppet movable in said valve chamber for opening and closing the valve chamber relative to said first lock chamber, a first actuator port connected to the valve chamber, a second actuator port connected to said first lock chamber, said first actuator port at times serving as an inlet for fluid and at other times as an outlet for fluid, said second actuator port serving as an outlet for fluid when said first actuator port serves as an inlet and serving as an inlet for fluid when the first actuator port serves as an outlet, a high pressure port connected to the second lock chamber, an exhaust port connected to the first relief chamber, a passage connecting the second relief chamber to the valve chamber, said lock piston being movable by high pressure in said second lock chamber into engagement with said valve poppet for moving the latter to open position, and said relief piston being movable by pressure in said second relief chamber into engagement with said lock piston to move the latter into engagement with said poppet for moving the poppet to its open position.
Claim 2
Dependent Claim
243 words
A combination lock and relief valve comprising a housing having a valve chamber, a lock cylinder and a relief cylinder, a lock piston dividing the lock cylinder into first and second lock chambers, a relief piston dividing the relief cylinder into first and second relief chambers, said first lock chamber communicating with said valve chamber, a valve poppet movable in said valve chamber for opening and closing the valve chamber relative to said first lock chamber, a first actuator port connected to the valve chamber, a second actuator port connected to said first lock chamber, said first actuator port at times serving as an inlet for fluid and at other times as an outlet for fluid, said second actuator port serving as an outlet for fluid when said first actuator port serves as an inlet and serving as an inlet for fluid when the first actuator port serves as an outlet, a high pressure port connected to the second lock chamber, an exhaust port connected to the first relief chamber, a passage connecting the second relief chamber to the valve chamber, said lock piston being movable by high pressure in said second lock chamber into engagement with said valve poppet for moving the latter to open position, and said relief piston being movable by pressure in said second relief chamber into engagement with said lock piston to move the latter into engagement with said poppet for moving the poppet to its open position.
Claim 3
Dependent Claim
36 words
The valve of claim 1 in which there is a bore between said second lock chamber and said first relief chamber and said engagement of said lock piston by said relief piston is through said bore.
Claim 4
Dependent Claim
33 words
The valve of claim 2 in which said bore is of smaller diameter than said relief piston and said relief piston has a rod extending through said bore to engage said lock piston.
Claim 5
Dependent Claim
75 words
The valve of claim 1 in which said relief piston has a first area exposed to fluid in said second relief chamber and has a second area exposed to fluid in said first relief chamber, and said relief piston has a third area exposed to fluid in said second lock chamber, said first area being greater than said third area and said second area being equal to the difference in said first and third areas.
Claim 6
Dependent Claim
42 words
The valve of claim 1 in which the relief piston has an effective area exposed to fluid in said second lock chamber and said poppet has an effective area exposed to fluid in said valve chamber, and said effective areas are equal.
Claim 7
Dependent Claim
41 words
The valve of claim 1 in which there is a lock spring urging the lock piston in a direction away from the poppet and there is a relief spring urging the relief piston in a direction away from the lock piston.
Claim 8
Dependent Claim
17 words
The valve of claim 6 in which said relief spring exerts more force than the lock spring.
Claim 9
Dependent Claim
37 words
The valve of claim 6 in which the relief piston includes a rod extending toward the lock piston for engaging the same and includes a flange in the second relief chamber against which said relief spring bears.
Claim 10
Dependent Claim
34 words
The valve of claim 8 in which the flange has a frusto-spherical surface and the relief spring bears against the flange by way of a follower sleeve between the relief spring and said surface.
Claim 11
Dependent Claim
22 words
The valve of claim 1 in which a packing ring seals the relief piston relative to a wall of said relief cylinder.
Claim 12
Dependent Claim
24 words
The valve of claim 3 in which there is a packing that seals the relief piston relative to a wall of said relief cylinder.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-16 | 1979-09-15 | 1980-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-16 | 1983-09-15 | 1984-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-16 | 1987-09-15 | 1988-03-16 | $7700.00 | Window Closed / Lapsed |