Patent US2452590A successfully refreshed from Google Patents.
US2452590A
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US
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Electric signaling system
Assignee: STC PLC
•
Filing: 1945-01-08
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Granted: 1948-11-02
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Expires: 1965-01-08
Abstract
No abstract record available.
Inventors
- 👤 Mcwhirter Eric Malcolm Swift
- 👤 Ward Hugh Jennings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:52
CPC Classifications
H; H02; H02J; H02J13/00; H02J13/18; H02J13/333
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US897662A
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US1695840A
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US1929402A
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US1938213A
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US2117580A
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US2103761A
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US2074423A
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US2129168A
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US2091301A
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US2276646A
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US2336064A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-11-02 | 1952-05-03 | 1952-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-11-02 | 1956-05-03 | 1956-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-11-02 | 1960-05-03 | 1960-11-02 | $7700.00 | Window Closed / Lapsed |