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Patent US2620401A successfully refreshed from Google Patents.
US2620401A
Expired / Lapsed
US
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Automatic telephone system
Assignee: Individual
•
Filing: 1947-07-10
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Granted: 1952-12-02
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Expires: 1967-07-10
Abstract
No abstract record available.
Inventors
- 👤 Vigren Sten Daniel
- 👤 Freese Harry
- 👤 Claesson Per Harry Elias
- 👤 Akesson Stig Per Robert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:50
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1757446A
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US1870621A
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US1886216A
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US1964526A
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US2183030A
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US2164335A
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US2317191A
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US2308637A
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US2332912A
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US2387018A
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US2379715A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-12-02 | 1956-06-02 | 1956-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-12-02 | 1960-06-02 | 1960-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-12-02 | 1964-06-02 | 1964-12-02 | $7700.00 | Window Closed / Lapsed |