US2753750A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Expandible mine roof bolt having continuous wedging engagement
Assignee: BRUGER Corp
•
Filing: 1955-05-04
•
Granted: 1956-07-10
•
Expires: 1975-05-04
Abstract
No abstract record available.
Inventors
- 👤 Joseph B Dempsey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:35
CPC Classifications
E; E21; E21D; E21D21/00; E21D21/008
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US13177A
Cited
US406565A
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US703652A
Cited
US927064A
Cited
US1139712A
Cited
US1352494A
Cited
GB402375A
Cited
US2667099A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-07-10 | 1960-01-09 | 1960-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-07-10 | 1964-01-09 | 1964-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-07-10 | 1968-01-09 | 1968-07-10 | $7700.00 | Window Closed / Lapsed |