US3170379A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic system
Assignee: Dempster Systems Inc
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Filing: 1962-02-13
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Granted: 1965-02-23
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Expires: 1982-02-13
Abstract
No abstract record available.
Inventors
- 👤 Dempster John Saylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:51
CPC Classifications
F; F15; F15B; F15B3/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
208 words
A HYDRAULIC SYSTEM COMPRISING A FLUID PUMP, AN EXPANSIBLE HYDRAULIC CYLINDER, TANDEM DOUBLE-ACTING PISTONS MOUNTED IN THE CYLINDER, MEANS CONNECTING THE PISTONS IN THE CYLINDER, SAID PISTONS AND SAID CYLINDER DEFINING WORKING CHAMBERS ON ONE SIDE OF THE PISTONS FOR FORWARD EXTENDING MOVEMENT OF THE CONNECTING MEANS AND WORKING CHAMBERS FOR RETURN TRAVEL OF THE CONNECTING MEANS ON THE OPPOSITE SIDE OF THE PISTONS, PORTS IN THE CYLINDER WALL COMMUNICATING WITH EACH OF THE WORKING CHAMBERS, A RESERVOIR, CONDUIT MEANS FOR SUPPLYING FLUID FROM THE RESERVOIR TO THE PUMP, FIRST VALVE MEANS, SECOND VALVE MEANS, CONDUIT MEANS FOR SUPPLYING FLUID FROM THE PUMP TO THE FIRST AND SECOND VALVE MEANS, CONDUIT MEANS FOR DISCHARGING FLUID FROM THE VALVE MEANS INDEPENDENTLY TO THE RESERVOIR, CONDUIT MEANS COMMUNICATING BETWEEN SAID FIRST AND SECOND VALVE MEANS AND SAID EXTENDING WORKING CHAMBERS, AND CONDUIT MEANS COMMUNICATING INDEPENDENTLY BETWEEN ONE OF SAID RETURN WORKING CHAMBERS AND SAID FIRST VALVE MEANS, AND BETWEEN THE OTHER OF SAID RETURN WORKING CHAMBERS AND SAID SECOND VALVE MEANS, SAID SECOND VALVE MEANS INCLUDING MEANS FOR SELECTIVELY PROVIDING COMMUNICATION BETWEEN SAID OTHER RETURN WORKING CHAMBER AND SAID EXTENDING WORKING CHAMBERS, WHEREBY A PLURALITY OF FORCES AND RATES OF TRAVEL OF THE CONNECTING MEANS IN THE CYLINDER ARE PROVIDED.
Claim 2
Dependent Claim
208 words
A HYDRAULIC SYSTEM COMPRISING A FLUID PUMP, AN EXPANSIBLE HYDRAULIC CYLINDER, TANDEM DOUBLE-ACTING PISTONS MOUNTED IN THE CYLINDER, MEANS CONNECTING THE PISTONS IN THE CYLINDER, SAID PISTONS AND SAID CYLINDER DEFINING WORKING CHAMBERS ON ONE SIDE OF THE PISTONS FOR FORWARD EXTENDING MOVEMENT OF THE CONNECTING MEANS AND WORKING CHAMBERS FOR RETURN TRAVEL OF THE CONNECTING MEANS ON THE OPPOSITE SIDE OF THE PISTONS, PORTS IN THE CYLINDER WALL COMMUNICATING WITH EACH OF THE WORKING CHAMBERS, A RESERVOIR, CONDUIT MEANS FOR SUPPLYING FLUID FROM THE RESERVOIR TO THE PUMP, FIRST VALVE MEANS, SECOND VALVE MEANS, CONDUIT MEANS FOR SUPPLYING FLUID FROM THE PUMP TO THE FIRST AND SECOND VALVE MEANS, CONDUIT MEANS FOR DISCHARGING FLUID FROM THE VALVE MEANS INDEPENDENTLY TO THE RESERVOIR, CONDUIT MEANS COMMUNICATING BETWEEN SAID FIRST AND SECOND VALVE MEANS AND SAID EXTENDING WORKING CHAMBERS, AND CONDUIT MEANS COMMUNICATING INDEPENDENTLY BETWEEN ONE OF SAID RETURN WORKING CHAMBERS AND SAID FIRST VALVE MEANS, AND BETWEEN THE OTHER OF SAID RETURN WORKING CHAMBERS AND SAID SECOND VALVE MEANS, SAID SECOND VALVE MEANS INCLUDING MEANS FOR SELECTIVELY PROVIDING COMMUNICATION BETWEEN SAID OTHER RETURN WORKING CHAMBER AND SAID EXTENDING WORKING CHAMBERS, WHEREBY A PLURALITY OF FORCES AND RATES OF TRAVEL OF THE CONNECTING MEANS IN THE CYLINDER ARE PROVIDED.
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) | 1968-02-23 | 1968-08-24 | 1969-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-02-23 | 1972-08-24 | 1973-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-02-23 | 1976-08-24 | 1977-02-23 | $7700.00 | Window Closed / Lapsed |