Patent US3286797A successfully refreshed from Google Patents.
US3286797A
Expired / Lapsed
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Hydraulic control unit
Assignee: Parker Hannifin Corp
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Filing: 1964-06-29
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Granted: 1966-11-22
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Expires: 1984-06-29
Abstract
No abstract record available.
Inventors
- 👤 Kurt W Leibfritz
- 👤 Kenneth A Bracki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:51
CPC Classifications
F; F15; F15B; F15B21/00; F15B21/10; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86718; Y10T137/86734
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
179 words
IN A HYDRAULIC CONTROL UNIT, THE COMBINATION OF A CYLINDER; A PISTON RECIPROCABLE IN SAID CYLINDER HAVING A PISTON ROD FOR ATTACHMENT TO A RECIPROCABLE DEVICE WHOSE MOVEMENTS ARE TO BE CONTROLLED; AN ADJUSTABLE METERING VALVE CONNECTED TO ONE END OF SAID CYLINDER FOR VARIABLY RESTRICTING THE FLOW OF FLUID FROM SAID CYLINDER THERETHROUGH THUS TO CONTROL THE RATE OF MOVEMENT OF SAID PISTON TOWARD SAID ONE END OF SAID CYLINDER; FIRST AND SECOND FLUID PRESSURE ACTUATED VALVES CONNECTED TO SAID METERING VALVE AND HAVING PASSAGES THERETHROUGH RESPECTIVELY TO BYPASS THE RESTRICTION OF SAID METERING VALVE AND TO PERMIT FLOW OF FLUID THERETHROUGH DOWNSTREAM OF SAID METERING VALVE; AND A MOVABLE VALVE MEMBER IN EACH FLUID PRESSURE ACTUATED VALVE HAVING A PLUNGER PORTION WHICH, WHEN COMMUNICATED WITH A PRESSURE SOURCE MOVES SAID VALVE MEMBER TO PASSAGE CLOSING POSITION WHEREBY, WHEN SAID FIRST VALVE IS CLOSED, MOVEMENT OF SAID PISTON TOWARD SAID ONE END OF SAID CYLINDER IS CONTROLLED BY SAID METERING VALVE AND, WHEN SAID SECOND VALVE IS CLOSED, MOVEMENT OF SAID PISTON TOWARD SAID ONE END IS STOPPED.
Claim 2
Dependent Claim
179 words
IN A HYDRAULIC CONTROL UNIT, THE COMBINATION OF A CYLINDER; A PISTON RECIPROCABLE IN SAID CYLINDER HAVING A PISTON ROD FOR ATTACHMENT TO A RECIPROCABLE DEVICE WHOSE MOVEMENTS ARE TO BE CONTROLLED; AN ADJUSTABLE METERING VALVE CONNECTED TO ONE END OF SAID CYLINDER FOR VARIABLY RESTRICTING THE FLOW OF FLUID FROM SAID CYLINDER THERETHROUGH THUS TO CONTROL THE RATE OF MOVEMENT OF SAID PISTON TOWARD SAID ONE END OF SAID CYLINDER; FIRST AND SECOND FLUID PRESSURE ACTUATED VALVES CONNECTED TO SAID METERING VALVE AND HAVING PASSAGES THERETHROUGH RESPECTIVELY TO BYPASS THE RESTRICTION OF SAID METERING VALVE AND TO PERMIT FLOW OF FLUID THERETHROUGH DOWNSTREAM OF SAID METERING VALVE; AND A MOVABLE VALVE MEMBER IN EACH FLUID PRESSURE ACTUATED VALVE HAVING A PLUNGER PORTION WHICH, WHEN COMMUNICATED WITH A PRESSURE SOURCE MOVES SAID VALVE MEMBER TO PASSAGE CLOSING POSITION WHEREBY, WHEN SAID FIRST VALVE IS CLOSED, MOVEMENT OF SAID PISTON TOWARD SAID ONE END OF SAID CYLINDER IS CONTROLLED BY SAID METERING VALVE AND, WHEN SAID SECOND VALVE IS CLOSED, MOVEMENT OF SAID PISTON TOWARD SAID ONE END IS STOPPED.
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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) | 1969-11-21 | 1970-05-23 | 1970-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-11-21 | 1974-05-23 | 1974-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-11-21 | 1978-05-23 | 1978-11-22 | $7700.00 | Window Closed / Lapsed |