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US3238548A
Expired / Lapsed
US
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Self-locking ramp
Assignee: ROLL RITE CORP
•
Filing: 1963-06-17
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Granted: 1966-03-08
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Expires: 1983-06-17
Abstract
No abstract record available.
Inventors
- 👤 Carl O Christensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:23
CPC Classifications
B; B65; B65G; B65G69/00; B65G69/28; B65G69/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US686490A
Cited
US2337138A
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US2452289A
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US2521349A
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US2461678A
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US2452222A
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US2659914A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-03-07 | 1969-09-06 | 1970-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-03-07 | 1973-09-06 | 1974-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-03-07 | 1977-09-06 | 1978-03-08 | $7700.00 | Window Closed / Lapsed |