US3501850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Teaching method and apparatus
Assignee: ALDA INSTRUMENTS Ltd
•
Filing: 1967-02-20
•
Granted: 1970-03-24
•
Expires: 1987-02-20
Abstract
No abstract record available.
Inventors
- 👤 Guy D Ouchterlony
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:06
CPC Classifications
G; G09; G09B; G09B15/00; G09B15/02; G09B15/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1696901A
Cited
DE1173777B
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US3186109A
Cited
US3199230A
Cited
US3190014A
Cited
US3300876A
Cited
US3377716A
Cited
US3314172A
Cited
US3395461A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-03-23 | 1973-09-22 | 1974-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-03-23 | 1977-09-22 | 1978-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-03-23 | 1981-09-22 | 1982-03-24 | $7700.00 | Window Closed / Lapsed |