US3275017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-stage servo valve
Assignee: American Brake Shoe Co
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Filing: 1964-03-03
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Granted: 1966-09-27
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Expires: 1984-03-03
Abstract
No abstract record available.
Inventors
- 👤 Augustus P Henry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:17
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/042; F15B13/043; F15B13/0436; Y; Y10; Y10T; Y10T137/00; Y10T137/2278; Y10T137/2322; Y10T137/2409; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86582
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
270 words
A THREE-STAGE SERVOVALVE COMPRISING A FIRST-STAGE VALVE, SAID FIRST-STAGE VALVE INCLUDING A FLUID INPUT PORT AND A FLUID OUTPUT PORT IN SAID FIRST-STAGE VALVE AND A PAIR OF PASSAGEWAYS CONNECTED TO SAID FIRST-STAGE VALVE, SAID FIRST-STAGE VALVE INCLUDING MEANS RESPONSIVE TO A SIGNAL FORCE APPLIED TO SAID FIRST-STAGE VALVE TO VALVE FLUID FROM SAID INPUT PORT INTO ONE OF SAID PASSAGEWAYS AND FROM THE OTHER OF SAID PASSAGEWAYS TO SAID OUTLET PORT FROM SAID FIRST-STAGE VALVE, A SECOND-STAGE VALVE, SAID SECOND-STAGE VALVE INCLUDING A SPOOL, CONTROL PRESSURE CHAMBERS ONE AT EACH END OF SAID SPOOL, SAID PASSAGEWAYS CONNECTED TO SAID CHAMBERS, A FLUID INLET PORT AND A FLUID RETURN PORTIN IN SAID SECOND-STAGE VALVE, A PAIR OF CONTROL PRESSURE PASSAGEWAYS CONNECTED TO SAID LAST NAMED FLUID INLET PORT AND TO SAID FLUID RETURN PORT, SAID SECOND-STAGE SPOOL VALVING FLUID FROM SAID LAST NAMED INLET PORT TO ONE OF SAID LAST NAMED PASSAGEWAYS TO SAID FROM THE OTHER OF SAID LAST NAMED PASSAGEWAYS TO SAID LAST NAMED RETURN PORT, A THIRD-STAGE VALVE, SAID THIRDSTAGE VALVE INCLUDING A SPOOL, A PAIR OF CONTROL PRESSURE CHAMBERS ONE AT EACH END OF SAID THIRD SPOOL, SAID LAST NAMED PASSAGEWAYS CONNECTED TO SAID LAST NAMED CONTROL PRESSURE CHAMBERS, A FLUID INLET PORT AND A FLUID RETURN PORT IN SAID THIRD-STAGE VALVE AND A PAIR OF LOAD PORTS IN SAID THIRD-STAGE VALVE, SAID THIRD-STAGE SPOOL VALVING FLUID FROM SAID LAST NAMED INPUT PORT TO ONE OF SAID LOAD PORTS AND FROM THE OTHER OF SAID LOAD PORTS TO SAID LAST NAMED RETURN PORT, FORCE FEEDBACK MEANS FROM SAID SECOND AND THIRD-STAGE SPOOL TO SAID FIRST-STAGE VALVE.
Claim 2
Dependent Claim
270 words
A THREE-STAGE SERVOVALVE COMPRISING A FIRST-STAGE VALVE, SAID FIRST-STAGE VALVE INCLUDING A FLUID INPUT PORT AND A FLUID OUTPUT PORT IN SAID FIRST-STAGE VALVE AND A PAIR OF PASSAGEWAYS CONNECTED TO SAID FIRST-STAGE VALVE, SAID FIRST-STAGE VALVE INCLUDING MEANS RESPONSIVE TO A SIGNAL FORCE APPLIED TO SAID FIRST-STAGE VALVE TO VALVE FLUID FROM SAID INPUT PORT INTO ONE OF SAID PASSAGEWAYS AND FROM THE OTHER OF SAID PASSAGEWAYS TO SAID OUTLET PORT FROM SAID FIRST-STAGE VALVE, A SECOND-STAGE VALVE, SAID SECOND-STAGE VALVE INCLUDING A SPOOL, CONTROL PRESSURE CHAMBERS ONE AT EACH END OF SAID SPOOL, SAID PASSAGEWAYS CONNECTED TO SAID CHAMBERS, A FLUID INLET PORT AND A FLUID RETURN PORTIN IN SAID SECOND-STAGE VALVE, A PAIR OF CONTROL PRESSURE PASSAGEWAYS CONNECTED TO SAID LAST NAMED FLUID INLET PORT AND TO SAID FLUID RETURN PORT, SAID SECOND-STAGE SPOOL VALVING FLUID FROM SAID LAST NAMED INLET PORT TO ONE OF SAID LAST NAMED PASSAGEWAYS TO SAID FROM THE OTHER OF SAID LAST NAMED PASSAGEWAYS TO SAID LAST NAMED RETURN PORT, A THIRD-STAGE VALVE, SAID THIRDSTAGE VALVE INCLUDING A SPOOL, A PAIR OF CONTROL PRESSURE CHAMBERS ONE AT EACH END OF SAID THIRD SPOOL, SAID LAST NAMED PASSAGEWAYS CONNECTED TO SAID LAST NAMED CONTROL PRESSURE CHAMBERS, A FLUID INLET PORT AND A FLUID RETURN PORT IN SAID THIRD-STAGE VALVE AND A PAIR OF LOAD PORTS IN SAID THIRD-STAGE VALVE, SAID THIRD-STAGE SPOOL VALVING FLUID FROM SAID LAST NAMED INPUT PORT TO ONE OF SAID LOAD PORTS AND FROM THE OTHER OF SAID LOAD PORTS TO SAID LAST NAMED RETURN PORT, FORCE FEEDBACK MEANS FROM SAID SECOND AND THIRD-STAGE SPOOL TO SAID FIRST-STAGE VALVE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-09-26 | 1970-03-28 | 1970-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-09-26 | 1974-03-28 | 1974-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-09-26 | 1978-03-28 | 1978-09-27 | $7700.00 | Window Closed / Lapsed |