Patent US3421072A successfully refreshed from Google Patents.
US3421072A
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Mechanically simulating electronic signal chopper
Assignee: VALID DATA CORP
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Filing: 1966-08-18
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Granted: 1969-01-07
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Expires: 1986-08-18
Abstract
No abstract record available.
Inventors
- 👤 Frank J Woolam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:27
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/687; H03K17/6877; H03F; H03F3/00; H03F3/38; H03F3/387; H03F3/393
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2959725A
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US3039042A
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US3177422A
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US3128438A
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US3305757A
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US3260921A
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US3341766A
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US3246176A
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US3317758A
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US3317856A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-01-07 | 1972-07-08 | 1973-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-01-07 | 1976-07-08 | 1977-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-01-07 | 1980-07-08 | 1981-01-07 | $7700.00 | Window Closed / Lapsed |