US2808661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reading apparatus for the blind
Assignee: Individual
•
Filing: 1952-11-13
•
Granted: 1957-10-08
•
Expires: 1972-11-13
Abstract
No abstract record available.
Inventors
- 👤 Alf M Berggreen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:27
CPC Classifications
G; G09; G09B; G09B21/00; G09B21/001; G09B21/003
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1790985A
Cited
US1453741A
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GB186686A
Cited
US1487115A
Cited
US1889576A
Cited
US2432123A
Cited
US2521338A
Cited
US2549632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-10-07 | 1961-04-08 | 1961-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-10-07 | 1965-04-08 | 1965-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-10-07 | 1969-04-08 | 1969-10-08 | $7700.00 | Window Closed / Lapsed |