Patent US2680833A successfully refreshed from Google Patents.
US2680833A
Expired / Lapsed
US
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Earth core magnetic analyzer
Assignee: H M R ELECTRONICS Inc
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Filing: 1950-10-24
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Granted: 1954-06-08
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Expires: 1970-10-24
Abstract
No abstract record available.
Inventors
- 👤 Rothacker Francis Neill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:58
CPC Classifications
E; E21; E21B; E21B47/00; E21B47/02; E21B47/026
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USRE21927E
Cited
GB164977A
Cited
US2105650A
Cited
US2260562A
Cited
US2334393A
Cited
US2425361A
Cited
GB600913A
Cited
US2410839A
Cited
US2519367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-06-07 | 1957-12-07 | 1958-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-06-07 | 1961-12-07 | 1962-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-06-07 | 1965-12-07 | 1966-06-08 | $7700.00 | Window Closed / Lapsed |