Patent US3491431A successfully refreshed from Google Patents.
US3491431A
Expired / Lapsed
US
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Method and devices for post-tensioning concrete and structural materials
Assignee: Individual
•
Filing: 1967-08-25
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Granted: 1970-01-27
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Expires: 1987-08-25
Abstract
No abstract record available.
Inventors
- 👤 Bernard B Pewitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:27
CPC Classifications
E; E04; E04G; E04G21/00; E04G21/12; E04G21/121; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49863; Y10T29/49874; Y10T29/53
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) | 1973-01-26 | 1973-07-28 | 1974-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-26 | 1977-07-28 | 1978-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-26 | 1981-07-28 | 1982-01-27 | $7700.00 | Window Closed / Lapsed |