US3255587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic jack with back pressure safety check
Assignee: Enerpac Tool Group Corp
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Filing: 1962-06-27
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Granted: 1966-06-14
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Expires: 1982-06-27
Abstract
No abstract record available.
Inventors
- 👤 Alvan G London
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:58
CPC Classifications
B; B66; B66F; B66F3/00; B66F3/24; B66F3/25; B66F3/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
158 words
A SAFTEY CIRCUIT FOR A HYDRAULIC SYSTEM COMPRISING IN COMBINATION, A HYDRAULIC PUMP HAVING AN INLET IN FLUID COMMUNICATION WITH A RESERVOIR AND AN OUTLET, A FIRST FLUID CONNECTION BETWEEN SAID OUTLET AND SAID RESERVOIR, AND A SECOND FLUID CONNECTION BETWEEN SAID RESERVOIR AND THE INTAKE OF SAID PUMP, A RELEASE VALVE FOR OPENING, PARTIALLY OPENING OR CLOSING SIAD FIRST FLUID CONNECTION, A LIFT JACK OPERABLE BY SAID PUMP, A HYDRAULIC BACK PRESSURE SAFETY HOUSING FORMING AN END WALL OF SAID JACK, A CONDUIT IN FLUID COMMUNICATION WITH SAID FIRST FLUID CONNECTION, SAID HOUSING HAVING A FIRST BORE RECEIVING SAID CONDUIT AND A SECOND BORE IN COMMUNICATION WITH SAID JACK, FIRST AND SECOND PASSAGEWAYS BETWEEN SAID BORES, A CHECK BALL IN SAID FIRST PASSAGEWAY NORMALLY BLOCKING FLUID FLOW THERETHROUGH FROM SAID SECOND BORE TO SAID FIRST BORE AND PERMITTING RELATIVELY FREE FLOW FROM SAID FIRST BORE TO SAID SECOND BORE, A ONE WAY CHECK VALVE AND A RESTRICTION
Claim 2
Dependent Claim
158 words
A SAFTEY CIRCUIT FOR A HYDRAULIC SYSTEM COMPRISING IN COMBINATION, A HYDRAULIC PUMP HAVING AN INLET IN FLUID COMMUNICATION WITH A RESERVOIR AND AN OUTLET, A FIRST FLUID CONNECTION BETWEEN SAID OUTLET AND SAID RESERVOIR, AND A SECOND FLUID CONNECTION BETWEEN SAID RESERVOIR AND THE INTAKE OF SAID PUMP, A RELEASE VALVE FOR OPENING, PARTIALLY OPENING OR CLOSING SIAD FIRST FLUID CONNECTION, A LIFT JACK OPERABLE BY SAID PUMP, A HYDRAULIC BACK PRESSURE SAFETY HOUSING FORMING AN END WALL OF SAID JACK, A CONDUIT IN FLUID COMMUNICATION WITH SAID FIRST FLUID CONNECTION, SAID HOUSING HAVING A FIRST BORE RECEIVING SAID CONDUIT AND A SECOND BORE IN COMMUNICATION WITH SAID JACK, FIRST AND SECOND PASSAGEWAYS BETWEEN SAID BORES, A CHECK BALL IN SAID FIRST PASSAGEWAY NORMALLY BLOCKING FLUID FLOW THERETHROUGH FROM SAID SECOND BORE TO SAID FIRST BORE AND PERMITTING RELATIVELY FREE FLOW FROM SAID FIRST BORE TO SAID SECOND BORE, A ONE WAY CHECK VALVE AND A RESTRICTION
References Cited (Backward Citations)
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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) | 1969-06-13 | 1969-12-13 | 1970-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-06-13 | 1973-12-13 | 1974-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-06-13 | 1977-12-13 | 1978-06-14 | $7700.00 | Window Closed / Lapsed |