US2468474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sound regulator for telephone ringers
Assignee: AT&T Inc
•
Filing: 1948-02-07
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Granted: 1949-04-26
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Expires: 1968-02-07
Abstract
No abstract record available.
Inventors
- 👤 William E Whidden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:41
CPC Classifications
B; B01; B01L; B01L3/00; B01L3/50; B01L3/502; B01L3/5021; G; G10; G10K; G10K1/00; G10K1/06; G10K1/062; G10K1/063; G10K1/064; G10K1/0645; H; H03; H03J; H03J1/00; H03J1/06
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) | 1952-04-25 | 1952-10-25 | 1953-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-04-25 | 1956-10-25 | 1957-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-04-25 | 1960-10-25 | 1961-04-26 | $7700.00 | Window Closed / Lapsed |