Patent US3540133A successfully refreshed from Google Patents.
US3540133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio visual teaching machine
Assignee: International Business Machines Corp
•
Filing: 1968-09-20
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Granted: 1970-11-17
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Expires: 1988-09-20
Abstract
No abstract record available.
Inventors
- 👤 Ronald V Davidge
- 👤 Robert A Kolpek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:58
CPC Classifications
G; G09; G09B; G09B7/00; G09B7/06; G09B7/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3353280A
Cited
US3383781A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-16 | 1974-05-18 | 1974-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-16 | 1978-05-18 | 1978-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-16 | 1982-05-18 | 1982-11-17 | $7700.00 | Window Closed / Lapsed |