US3306050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mine roof support
Assignee: Dowty Technical Developments Ltd
•
Filing: 1964-04-03
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Granted: 1967-02-28
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Expires: 1984-04-03
Abstract
No abstract record available.
Inventors
- 👤 Andrews Thomas Desmond Hudson
- 👤 Harding John Kammerer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:43
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
177 words
ROOF SUPPORT APPARATUS INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORT INCLUDING AT LEAST ONE FLUID-PRESSURE-OPERATED PROP DEVICE OPERABLE TO SET THE SUPPORT AGAINST A ROOF, A FLUID-PRESSURE-OPERATED JACK DEVICE OPERABLE TO CAUSE RELATIVE MOVEMENT BETWEEN THE SUPPORT AND AN ANCHORAGE, A VALVE ASSEMBLY OPERABLE TO CONTROL THE OPERATION OF THE PROP AND THE JACK, AND A FLUID-CARRYING PILOT LINE CONNECTED TO THE VALVE ASSEMBLY OF EACH SUPPORT IN TURN AND TO A SOURCE OF FLUID UNDER PRESSURE OPERABLE TO VARY THE FLUID PRESSURE IN THE PILOT LINE IN A PREDETERMINED MANNER, THE VALVE ASSEMBLY OF THE FIRST SUPPORT IN THE SERIES INCLUDING MEANS OPERABLE BY THE PRESSURISATION OF THE PILOT LINE TO ONE VALUE TO CAUSE THE OPERATION OF ONE OF THE DEVICES OF THE SUPPORT AND BEING OPERABLE BY A PREDETERMINED CHANGE IN PRESSURE IN THE PILOT LINE FROM SAID ONE VALUE TO CAUSE THE VALVE ASSEMBLY OF THE FIRST SUPPORT TO OPEN THE PILOT LINE TO THE VALVE ASSEMBLY OF THE NEXT SUPPORT IN THE SERIES, AND SO ON THROUGHOUT THE SERIES.
Claim 2
Dependent Claim
177 words
ROOF SUPPORT APPARATUS INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORT INCLUDING AT LEAST ONE FLUID-PRESSURE-OPERATED PROP DEVICE OPERABLE TO SET THE SUPPORT AGAINST A ROOF, A FLUID-PRESSURE-OPERATED JACK DEVICE OPERABLE TO CAUSE RELATIVE MOVEMENT BETWEEN THE SUPPORT AND AN ANCHORAGE, A VALVE ASSEMBLY OPERABLE TO CONTROL THE OPERATION OF THE PROP AND THE JACK, AND A FLUID-CARRYING PILOT LINE CONNECTED TO THE VALVE ASSEMBLY OF EACH SUPPORT IN TURN AND TO A SOURCE OF FLUID UNDER PRESSURE OPERABLE TO VARY THE FLUID PRESSURE IN THE PILOT LINE IN A PREDETERMINED MANNER, THE VALVE ASSEMBLY OF THE FIRST SUPPORT IN THE SERIES INCLUDING MEANS OPERABLE BY THE PRESSURISATION OF THE PILOT LINE TO ONE VALUE TO CAUSE THE OPERATION OF ONE OF THE DEVICES OF THE SUPPORT AND BEING OPERABLE BY A PREDETERMINED CHANGE IN PRESSURE IN THE PILOT LINE FROM SAID ONE VALUE TO CAUSE THE VALVE ASSEMBLY OF THE FIRST SUPPORT TO OPEN THE PILOT LINE TO THE VALVE ASSEMBLY OF THE NEXT SUPPORT IN THE SERIES, AND SO ON THROUGHOUT THE SERIES.
References Cited (Backward Citations)
US3216201A
Cited
US3217605A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-02-27 | 1970-08-29 | 1971-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-02-27 | 1974-08-29 | 1975-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-02-27 | 1978-08-29 | 1979-02-28 | $7700.00 | Window Closed / Lapsed |