Patent US2418487A successfully refreshed from Google Patents.
US2418487A
Expired / Lapsed
US
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Cathode ray magnetic focusing device
Assignee: AT&T Inc
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Filing: 1944-03-31
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Granted: 1947-04-08
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Expires: 1964-03-31
Abstract
No abstract record available.
Inventors
- 👤 Philip T Sproul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:55
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/58; H01J29/64; H01J29/68
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-04-07 | 1950-10-07 | 1951-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-04-07 | 1954-10-07 | 1955-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-04-07 | 1958-10-07 | 1959-04-08 | $7700.00 | Window Closed / Lapsed |