US2415342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for use in learning reading and arithmetic
Assignee: Individual
•
Filing: 1944-11-03
•
Granted: 1947-02-04
•
Expires: 1964-11-03
Abstract
No abstract record available.
Inventors
- 👤 Donner Lawrence Frederick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:58
CPC Classifications
G; G09; G09B; G09B17/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US275329A
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US723425A
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US1396379A
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US1230263A
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GB214098A
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US1539009A
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US1902404A
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US1856650A
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US1836851A
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US1980637A
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US2190881A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-02-03 | 1950-08-05 | 1951-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-02-03 | 1954-08-05 | 1955-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-02-03 | 1958-08-05 | 1959-02-04 | $7700.00 | Window Closed / Lapsed |