US3452449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Teaching aid and method
Assignee: Individual
•
Filing: 1966-05-12
•
Granted: 1969-07-01
•
Expires: 1986-05-12
Abstract
No abstract record available.
Inventors
- 👤 John Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:21
CPC Classifications
G; G09; G09B; G09B7/00; G09B7/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3137948A
Cited
US3141243A
Cited
US3117382A
Cited
US3191315A
Cited
US3286372A
Cited
FR1386930A
Cited
FR1415547A
Cited
US3344435A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-30 | 1972-12-30 | 1973-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-30 | 1976-12-30 | 1977-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-30 | 1980-12-30 | 1981-07-01 | $7700.00 | Window Closed / Lapsed |