US2426918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for electromagnetic-wave investigations of earth formations
Assignee: ENGINEERING RES CORP
•
Filing: 1941-03-17
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Granted: 1947-09-02
•
Expires: 1961-03-17
Abstract
No abstract record available.
Inventors
- 👤 William M Barret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:24
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2139460A
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US2153051A
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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) | 1950-09-01 | 1951-03-03 | 1951-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-09-01 | 1955-03-03 | 1955-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-09-01 | 1959-03-03 | 1959-09-02 | $7700.00 | Window Closed / Lapsed |