US2866276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Core device for teaching electricity and magnetism
Assignee: Individual
•
Filing: 1957-08-12
•
Granted: 1958-12-30
•
Expires: 1977-08-12
Abstract
No abstract record available.
Inventors
- 👤 Cletus E Zumwalt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:32
CPC Classifications
G; G09; G09B; G09B23/00; G09B23/06; G09B23/18; G09B23/182; H; H01; H01F; H01F30/00; H01F30/06; H01F30/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US400972A
Cited
FR621970A
Cited
US1803353A
Cited
US1698634A
Cited
GB344961A
Cited
US2374449A
Cited
US2617092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-12-29 | 1962-06-30 | 1962-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-29 | 1966-06-30 | 1966-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-29 | 1970-06-30 | 1970-12-30 | $7700.00 | Window Closed / Lapsed |