Patent US2643820A successfully refreshed from Google Patents.
US2643820A
Expired / Lapsed
US
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Circuit for adding binary numbers
Assignee: National Research Development Corp UK
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Filing: 1949-12-12
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Granted: 1953-06-30
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Expires: 1969-12-12
Abstract
No abstract record available.
Inventors
- 👤 Frederic C Williams
- 👤 Arthur A Robinson
- 👤 Kilburn Tom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:50
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/50; G06F7/504
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) | 1956-06-29 | 1956-12-29 | 1957-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-29 | 1960-12-29 | 1961-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-29 | 1964-12-29 | 1965-06-30 | $7700.00 | Window Closed / Lapsed |