US2977416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric signalling systems
Assignee: National Research Development Corp UK
•
Filing: 1957-03-28
•
Granted: 1961-03-28
•
Expires: 1977-03-28
Abstract
No abstract record available.
Inventors
- 👤 Robin Harold Kilner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:14
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/22; H04L5/26
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1326727A
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US2008273A
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US2065640A
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US2301373A
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US2495705A
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US2446077A
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US2423225A
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US2570716A
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US2833857A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-03-27 | 1964-09-26 | 1965-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-03-27 | 1968-09-26 | 1969-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-03-27 | 1972-09-26 | 1973-03-28 | $7700.00 | Window Closed / Lapsed |