US2777251A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-oscillating double tone whistle
Assignee: AT&T Inc
•
Filing: 1954-06-29
•
Granted: 1957-01-15
•
Expires: 1974-06-29
Abstract
No abstract record available.
Inventors
- 👤 Bailey Austin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:12
CPC Classifications
G; G10; G10K; G10K5/00; Y; Y10; Y10S; Y10S116/00; Y10S116/42; Y10T; Y10T137/00; Y10T137/8593; Y10T137/877; Y10T137/87788; Y10T137/87812
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US396821A
Cited
US492987A
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US787565A
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US1383878A
Cited
US1609641A
Cited
US1767658A
Cited
US1851034A
Cited
US2056623A
Cited
DE911208C
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-01-15 | 1960-07-16 | 1961-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-01-15 | 1964-07-16 | 1965-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-01-15 | 1968-07-16 | 1969-01-15 | $7700.00 | Window Closed / Lapsed |