Patent US2472439A successfully refreshed from Google Patents.
US2472439A
Expired / Lapsed
US
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Device for teaching arithmetic
Assignee: Individual
•
Filing: 1945-10-05
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Granted: 1949-06-07
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Expires: 1965-10-05
Abstract
No abstract record available.
Inventors
- 👤 Alban E Rogers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:49
CPC Classifications
G; G09; G09B; G09B19/00; G09B19/02
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-06-06 | 1952-12-06 | 1953-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-06-06 | 1956-12-06 | 1957-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-06-06 | 1960-12-06 | 1961-06-07 | $7700.00 | Window Closed / Lapsed |