US2701423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Educational device with interfittable problem and answer members
Assignee: Individual
•
Filing: 1952-02-01
•
Granted: 1955-02-08
•
Expires: 1972-02-01
Abstract
No abstract record available.
Inventors
- 👤 Albert H Merrill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:56
CPC Classifications
G; G09; G09B; G09B19/00; G09B19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US163912A
Cited
US777268A
Cited
US1050327A
Cited
US1624450A
Cited
US1735456A
Cited
US2645041A
Cited
US2645038A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-02-07 | 1958-08-09 | 1959-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-02-07 | 1962-08-09 | 1963-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-02-07 | 1966-08-09 | 1967-02-08 | $7700.00 | Window Closed / Lapsed |