US3387889A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coal dust removal and conveyance system
Assignee: ANTHONY J ZIEMBA
•
Filing: 1966-11-03
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Granted: 1968-06-11
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Expires: 1986-11-03
Abstract
No abstract record available.
Inventors
- 👤 Stanley C Ziemba
- 👤 Josephine A Ziemba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:33
CPC Classifications
E; E21; E21C; E21C35/00; E21C35/22; E21C35/223
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-06-11 | 1971-12-11 | 1972-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-06-11 | 1975-12-11 | 1976-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-06-11 | 1979-12-11 | 1980-06-11 | $7700.00 | Window Closed / Lapsed |