US2840926A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Memorizing aid
Assignee: Individual
•
Filing: 1957-02-18
•
Granted: 1958-07-01
•
Expires: 1977-02-18
Abstract
No abstract record available.
Inventors
- 👤 Floyd A Campbell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:44
CPC Classifications
G; G09; G09B; G09B29/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR601043A
Cited
US1609959A
Cited
US1879501A
Cited
US1864022A
Cited
GB508570A
Cited
US2270137A
Cited
GB524295A
Cited
US2493668A
Cited
US2628435A
Cited
US2715784A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-06-30 | 1961-12-30 | 1962-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-06-30 | 1965-12-30 | 1966-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-06-30 | 1969-12-30 | 1970-07-01 | $7700.00 | Window Closed / Lapsed |