Patent US3413813A successfully refreshed from Google Patents.
US3413813A
Expired / Lapsed
US
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Tunnel support including a yieldable connection
Assignee: Pittsburgh Des Moines Steel Co
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Filing: 1966-03-09
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Granted: 1968-12-03
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Expires: 1986-03-09
Abstract
No abstract record available.
Inventors
- 👤 James H Rock
- 👤 Sr Lloyd E Anderson
- 👤 Buckwalter Milton Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:00
CPC Classifications
E; E21; E21D; E21D11/00; E21D11/14; E21D11/18; E21D11/183; Y; Y10; Y10T; Y10T403/00; Y10T403/55; Y10T403/553
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) | 1971-12-03 | 1972-06-03 | 1972-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-12-03 | 1976-06-03 | 1976-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-12-03 | 1980-06-03 | 1980-12-03 | $7700.00 | Window Closed / Lapsed |