Patent US3217608A successfully refreshed from Google Patents.
US3217608A
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Mining apparatus
Assignee: Dowty Mining Equipment Ltd
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Filing: 1964-10-15
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Granted: 1965-11-16
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Expires: 1984-10-15
Abstract
No abstract record available.
Inventors
- 👤 Bolton Douglas Herbert Hewlett
- 👤 Potts Michael Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:01
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/16; E21D23/26; E21C; E21C35/00; E21C35/08; E21C35/12; E21C35/14; E21F; E21F13/00; E21F13/08; E21F13/086
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
97 words
MINING APPARATUS INCLUDING A CONVEYOR EXTENDING ALONG THE WORKING FACE OF A MINE, A SERIES OF FLUID-PRESSURE-OPERATED CONVEYOR-ADVANCING DEVICES SPACED ALONG THE LENGTH OF THE CONVEYOR, A VALVE ASSEMBLY ASSOCIATED WITH EACH DEVICE, AND A CONDUIT CONNECTING EACH VALVE ASSEMBLY TO AN ADJACENT VALVE ASSEMBLY, EACH VALVE ASSEMBLY INCLUDING A PRESSURE REDUCING VALVE THROUGH WHICH FLUID FLOWS WHEN PASSING FROM ONE CONDUIT TO ANOTHER CONDUIT, EACH PRESSURE REDUCING VALVE OPERATING TO REDUCE FLUID PRESSURE BY A PREDETERMINED AMOUNT, EACH VALVE ASSEMBLY INCLUDING MEANS RESPONSIVE TO THE ATTAINMENT OF A PREDETERMINED FLUID PRESSURE IN A CONDUIT CONNECTED TO
Claim 2
Dependent Claim
97 words
MINING APPARATUS INCLUDING A CONVEYOR EXTENDING ALONG THE WORKING FACE OF A MINE, A SERIES OF FLUID-PRESSURE-OPERATED CONVEYOR-ADVANCING DEVICES SPACED ALONG THE LENGTH OF THE CONVEYOR, A VALVE ASSEMBLY ASSOCIATED WITH EACH DEVICE, AND A CONDUIT CONNECTING EACH VALVE ASSEMBLY TO AN ADJACENT VALVE ASSEMBLY, EACH VALVE ASSEMBLY INCLUDING A PRESSURE REDUCING VALVE THROUGH WHICH FLUID FLOWS WHEN PASSING FROM ONE CONDUIT TO ANOTHER CONDUIT, EACH PRESSURE REDUCING VALVE OPERATING TO REDUCE FLUID PRESSURE BY A PREDETERMINED AMOUNT, EACH VALVE ASSEMBLY INCLUDING MEANS RESPONSIVE TO THE ATTAINMENT OF A PREDETERMINED FLUID PRESSURE IN A CONDUIT CONNECTED TO
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) | 1968-11-15 | 1969-05-17 | 1969-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-11-15 | 1973-05-17 | 1973-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-11-15 | 1977-05-17 | 1977-11-16 | $7700.00 | Window Closed / Lapsed |