Patent GB742501A successfully refreshed from Google Patents.
US2504999A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric signaling system
Assignee: International Standard Electric Corp
•
Filing: 1947-04-25
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Granted: 1950-04-25
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Expires: 1967-04-25
Abstract
No abstract record available.
Inventors
- 👤 Mcwhirter Eric Malcolm Swift
- 👤 Dunn Roland Harris
- 👤 Peter William Lennox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:42
CPC Classifications
G; G08; G08C; G08C15/00; G08C15/06; G08C15/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2317995A
Cited
US2207744A
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US2207743A
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US2302535A
Cited
US2372593A
Cited
US2428089A
Cited
US2403890A
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US2381920A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-04-24 | 1953-10-24 | 1954-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-04-24 | 1957-10-24 | 1958-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-04-24 | 1961-10-24 | 1962-04-25 | $7700.00 | Window Closed / Lapsed |