Patent US2275912A successfully refreshed from Google Patents.
US2275912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System of working bedlike deposits, particularly thick beds of lignite and mineral coal
Assignee: Individual
•
Filing: 1940-06-06
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Granted: 1942-03-10
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Expires: 1960-06-06
Abstract
No abstract record available.
Inventors
- 👤 Lehmann Karl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:11
CPC Classifications
E; E21; E21C; E21C41/00; E21C41/16
Claims Analysis
Total Claims: 0
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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) | 1945-03-09 | 1945-09-08 | 1946-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-03-09 | 1949-09-08 | 1950-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-03-09 | 1953-09-08 | 1954-03-10 | $7700.00 | Window Closed / Lapsed |