US2641906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mine roof support
Assignee: Dowty Equipment Ltd
•
Filing: 1949-08-31
•
Granted: 1953-06-16
•
Expires: 1969-08-31
Abstract
No abstract record available.
Inventors
- 👤 Richard N Knights
- 👤 Colin M Frye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:08
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/006; E21D23/0073; E21D15/00; E21D15/14; E21D15/44; E21D23/0065
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1473157A
Cited
US1870088A
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US2163959A
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US2152654A
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US2420755A
Cited
US2452632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-15 | 1956-12-15 | 1957-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-15 | 1960-12-15 | 1961-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-15 | 1964-12-15 | 1965-06-16 | $7700.00 | Window Closed / Lapsed |