Patent US2787250A successfully refreshed from Google Patents.
US2787250A
Expired / Lapsed
US
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Rock drilling apparatus
Assignee: CLEVELAND ROCK DRILL DIVISION
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Filing: 1955-02-23
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Granted: 1957-04-02
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Expires: 1975-02-23
Abstract
No abstract record available.
Inventors
- 👤 Jacob E Feucht
- 👤 Henry W Hauch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:40
CPC Classifications
E; E21; E21B; E21B19/00; E21B19/08; E21B19/084
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2055520A
Cited
US2385946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-04-01 | 1960-10-01 | 1961-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-04-01 | 1964-10-01 | 1965-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-04-01 | 1968-10-01 | 1969-04-02 | $7700.00 | Window Closed / Lapsed |