US2804095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air ducts for mines and the like
Assignee: Individual
•
Filing: 1953-05-04
•
Granted: 1957-08-27
•
Expires: 1973-05-04
Abstract
No abstract record available.
Inventors
- 👤 Schauenburg Hans Georg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:19
CPC Classifications
E; E21; E21F; E21F1/00; E21F1/04
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-26 | 1961-02-25 | 1961-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-26 | 1965-02-25 | 1965-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-26 | 1969-02-25 | 1969-08-27 | $7700.00 | Window Closed / Lapsed |