US3521380A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron shell model
Assignee: HARCOURT BRACE AND WORLD Inc
•
Filing: 1968-01-08
•
Granted: 1970-07-21
•
Expires: 1988-01-08
Abstract
No abstract record available.
Inventors
- 👤 Hyman Ruchlis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:41
CPC Classifications
G; G09; G09B; G09B23/00; G09B23/26
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2492563A
Cited
US2477179A
Cited
US2586039A
Cited
US2961779A
Cited
US3091041A
Cited
US3365815A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |