US3380176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-correcting educational device, game and associative display
Assignee: Educational Testing Service
•
Filing: 1966-06-02
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Granted: 1968-04-30
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Expires: 1986-06-02
Abstract
No abstract record available.
Inventors
- 👤 Frederick R Kling
- 👤 Serrell Robert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:10
CPC Classifications
G; G09; G09B; G09B1/00; G09B1/02; G09B1/04; G09B1/06; G09B1/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US142338A
Cited
US1084370A
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US2415342A
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US2490092A
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US2839843A
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US2971275A
Cited
US3010228A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-04-30 | 1971-10-30 | 1972-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-04-30 | 1975-10-30 | 1976-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-04-30 | 1979-10-30 | 1980-04-30 | $7700.00 | Window Closed / Lapsed |