US2721055A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Core drill
Assignee: Individual
•
Filing: 1951-08-29
•
Granted: 1955-10-18
•
Expires: 1971-08-29
Abstract
No abstract record available.
Inventors
- 👤 Leo D Madson
- 👤 Hamilton P Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:19
CPC Classifications
E; E21; E21B; E21B25/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1505346A
Cited
US1648225A
Cited
US1733312A
Cited
US1640264A
Cited
US1791370A
Cited
US1853581A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-10-17 | 1959-04-18 | 1959-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-17 | 1963-04-18 | 1963-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-17 | 1967-04-18 | 1967-10-18 | $7700.00 | Window Closed / Lapsed |