US3812883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanism for preventing the sticking of spool valves
Assignee: Sumitomo Precision Products Co Ltd
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Filing: 1972-04-05
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Granted: 1974-05-28
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Expires: 1992-04-05
Abstract
Abstract This invention is to make many annular grooves with a very narrow land width on the outer peripheral surface of the land of spool or on the inner peripheral surface of the spool hole of a valve body.
Inventors
- 👤 T Yokokawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:26
CPC Classifications
F; F16; F16K; F16K11/00; F16K11/02; F16K11/06; F16K11/065; F16K11/07; F16K11/0708; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/8667; Y10T137/86694; Y10T137/8671
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
70 words
A spool valve disposed within the oil laden bore of a valve body for sliding movement along the longitudinal axis of the valve, characterized by a plurality of annular grooves provided along the outer periphery of the spool valve, the land width between adjacent ones of said grooves being less than 0.5 mm whereby any sticking between the spool valve and the bore of said valve body is substantially avoided.
Claim 2
Dependent Claim
70 words
A spool valve disposed within the oil laden bore of a valve body for sliding movement along the longitudinal axis of the valve, characterized by a plurality of annular grooves provided along the outer periphery of the spool valve, the land width between adjacent ones of said grooves being less than 0.5 mm whereby any sticking between the spool valve and the bore of said valve body is substantially avoided.
References Cited (Backward Citations)
US1288811A
Cited
US1363248A
Cited
US2646815A
Cited
US2879788A
Cited
US3303831A
Cited
US3393702A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |