US2937049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and an apparatus for carrying coals out of a vertical shaft with the aid of heavy liquid in the coal mine
Assignee: Individual
•
Filing: 1955-05-23
•
Granted: 1960-05-17
•
Expires: 1975-05-23
Abstract
No abstract record available.
Inventors
- 👤 Osawa Hirosaburo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:16
CPC Classifications
E; E21; E21F; E21F13/00; E21F13/04; E21F13/042
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US616537A
Cited
US1559937A
Cited
US2376139A
Cited
GB567079A
Cited
US2453458A
Cited
GB587335A
Cited
US2547015A
Cited
US2516962A
Cited
US2704704A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-05-17 | 1963-11-16 | 1964-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-05-17 | 1967-11-16 | 1968-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-05-17 | 1971-11-16 | 1972-05-17 | $7700.00 | Window Closed / Lapsed |