Patent US3520443A successfully refreshed from Google Patents.
US3520443A
Expired / Lapsed
US
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Safety vent structure
Assignee: Union Tank Car Co
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Filing: 1968-06-04
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Granted: 1970-07-14
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Expires: 1988-06-04
Abstract
No abstract record available.
Inventors
- 👤 Roger M Selby Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:41
CPC Classifications
B; B65; B65D; B65D90/00; B65D90/22; B65D90/32; B65D90/34
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) | 1973-07-13 | 1974-01-12 | 1974-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-13 | 1978-01-12 | 1978-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-13 | 1982-01-12 | 1982-07-14 | $7700.00 | Window Closed / Lapsed |