Patent CA834073A successfully refreshed from Google Patents.
US3272084A
Expired / Lapsed
US
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Roof support assemblies suitable for use in mines
Assignee: Dowty Mining Equipment Ltd
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Filing: 1965-05-13
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Granted: 1966-09-13
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Expires: 1985-05-13
Abstract
No abstract record available.
Inventors
- 👤 Bolton Douglas Herbert Hewlett
- 👤 Pawling Frank
- 👤 Potts Michael Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:18
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/16; E21D23/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
89 words
A ROOF SUPPORT ASSEMBLY INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORTS HAVING AT LEAST ONE FLUID-PRESSURE-OPERATED PROP OPERABLE TO SET THE SUPPORT AGAINST A ROOF AND A FLUID-PRESSURE-OPERATED JACK OPERABLE TO ADVANCE THE SUPPORT, EACH ROOF SUPPORT ALSO HAVING A VALVE ASSEMBLY CONTROLLING THE OPERATION OF THE PROP AND THE JACK, THE VALVE ASSEMBLY BEING OPERATED BY THE RECEIPT OF A SIGNAL FROM THE PRECEDING ROOF SUPPORT IN THE SERIES TO CAUSE ITS ROOF SUPPORT TO UNDERGO AN ADVANCING OPERATION, AND THE VALVE ASSEMBLY BEING RESPON-
Claim 2
Dependent Claim
89 words
A ROOF SUPPORT ASSEMBLY INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORTS HAVING AT LEAST ONE FLUID-PRESSURE-OPERATED PROP OPERABLE TO SET THE SUPPORT AGAINST A ROOF AND A FLUID-PRESSURE-OPERATED JACK OPERABLE TO ADVANCE THE SUPPORT, EACH ROOF SUPPORT ALSO HAVING A VALVE ASSEMBLY CONTROLLING THE OPERATION OF THE PROP AND THE JACK, THE VALVE ASSEMBLY BEING OPERATED BY THE RECEIPT OF A SIGNAL FROM THE PRECEDING ROOF SUPPORT IN THE SERIES TO CAUSE ITS ROOF SUPPORT TO UNDERGO AN ADVANCING OPERATION, AND THE VALVE ASSEMBLY BEING RESPON-
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-09-12 | 1970-03-14 | 1970-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-09-12 | 1974-03-14 | 1974-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-09-12 | 1978-03-14 | 1978-09-13 | $7700.00 | Window Closed / Lapsed |