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US2802284A
Expired / Lapsed
US
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Educational means for visual instruction in the operation of a keyboard device
Assignee: Individual
•
Filing: 1953-09-01
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Granted: 1957-08-13
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Expires: 1973-09-01
Abstract
No abstract record available.
Inventors
- 👤 Richard H Dreisonstok
- 👤 William L Llewellin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:56
CPC Classifications
G; G09; G09B; G09B13/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-12 | 1961-02-11 | 1961-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-12 | 1965-02-11 | 1965-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-12 | 1969-02-11 | 1969-08-13 | $7700.00 | Window Closed / Lapsed |