Patent US2255829A successfully refreshed from Google Patents.
US2255829A
Expired / Lapsed
US
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Safety drilling-in head
Assignee: Individual
•
Filing: 1939-06-20
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Granted: 1941-09-16
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Expires: 1959-06-20
Abstract
No abstract record available.
Inventors
- 👤 Ferdinand J Spang
- 👤 Ray B Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:17
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/02; E21B33/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1944-09-15 | 1945-03-17 | 1945-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-09-15 | 1949-03-17 | 1949-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-09-15 | 1953-03-17 | 1953-09-16 | $7700.00 | Window Closed / Lapsed |