US3144720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Teaching machine
Assignee: Individual
•
Filing: 1962-04-06
•
Granted: 1964-08-18
•
Expires: 1982-04-06
Abstract
No abstract record available.
Inventors
- 👤 Leslie L Kehl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 02:38
CPC Classifications
G; G09; G09B; G09B3/00; G09B3/06; G09B3/08
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) | 1967-08-18 | 1968-02-17 | 1968-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-08-18 | 1972-02-17 | 1972-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-08-18 | 1976-02-17 | 1976-08-18 | $7700.00 | Window Closed / Lapsed |