US3491464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Teaching system
Assignee: Raytheon Education Co
•
Filing: 1967-01-23
•
Granted: 1970-01-27
•
Expires: 1987-01-23
Abstract
No abstract record available.
Inventors
- 👤 Michael T Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:32
CPC Classifications
G; G09; G09B; G09B7/00; G09B7/06; G09B7/07; G09B7/073
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3299254A
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US3303472A
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US3186110A
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US3186109A
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US3199230A
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US3270438A
Cited
US3190014A
Cited
US3300876A
Cited
US3266174A
Cited
US3344408A
Cited
US3314172A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-01-26 | 1973-07-28 | 1974-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-26 | 1977-07-28 | 1978-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-26 | 1981-07-28 | 1982-01-27 | $7700.00 | Window Closed / Lapsed |