Patent US2669441A successfully refreshed from Google Patents.
US2669441A
Expired / Lapsed
US
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Coal boring unit
Assignee: Individual
•
Filing: 1950-01-04
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Granted: 1954-02-16
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Expires: 1970-01-04
Abstract
No abstract record available.
Inventors
- 👤 Alder F Castanoli
- 👤 Desmond F Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:00
CPC Classifications
E; E21; E21F; E21F13/00; E21F13/04; E21F13/047; E21D; E21D9/00; E21D9/005
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US973107A
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US1179342A
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US1219419A
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US1050171A
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US1445085A
Cited
US1653111A
Cited
US1511957A
Cited
US1603621A
Cited
US1618338A
Cited
US1699936A
Cited
US2182477A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-15 | 1957-08-17 | 1958-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-15 | 1961-08-17 | 1962-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-15 | 1965-08-17 | 1966-02-16 | $7700.00 | Window Closed / Lapsed |