US2738769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rock drilling apparatus
Assignee: Holman Brothers Ltd
•
Filing: 1953-05-11
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Granted: 1956-03-20
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Expires: 1973-05-11
Abstract
No abstract record available.
Inventors
- 👤 Holman Richard Carthew
- 👤 James Eric Basil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:15
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/01
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) | 1959-03-20 | 1959-09-19 | 1960-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-03-20 | 1963-09-19 | 1964-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-03-20 | 1967-09-19 | 1968-03-20 | $7700.00 | Window Closed / Lapsed |