US2989648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic null detecting system
Assignee: Individual
•
Filing: 1957-07-01
•
Granted: 1961-06-20
•
Expires: 1977-07-01
Abstract
No abstract record available.
Inventors
- 👤 David C Kalbfell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:23
CPC Classifications
G; G05; G05B; G05B1/00; G05B1/01; G05B1/02; G05B1/025
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2666151A
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US2809302A
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US2770738A
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US2828477A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-06-19 | 1964-12-19 | 1965-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-06-19 | 1968-12-19 | 1969-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-06-19 | 1972-12-19 | 1973-06-20 | $7700.00 | Window Closed / Lapsed |