US2804699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Educational device for decimal numeration
Assignee: Individual
•
Filing: 1953-12-18
•
Granted: 1957-09-03
•
Expires: 1973-12-18
Abstract
No abstract record available.
Inventors
- 👤 Donald K Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:46
CPC Classifications
G; G09; G09B; G09B19/00; G09B19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US480164A
Cited
US1327775A
Cited
CH122089A
Cited
US1863927A
Cited
GB587220A
Cited
US2457332A
Cited
US2527080A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-09-02 | 1961-03-04 | 1961-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-02 | 1965-03-04 | 1965-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-02 | 1969-03-04 | 1969-09-03 | $7700.00 | Window Closed / Lapsed |