Patent US1991206A successfully refreshed from Google Patents.
US1991206A
Expired / Lapsed
US
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Apparatus for making acoustic resistances
Assignee: AT&T Inc
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Filing: 1933-03-16
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Granted: 1935-02-12
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Expires: 1953-03-16
Abstract
No abstract record available.
Inventors
- 👤 Henry C Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:55
CPC Classifications
B; B21; B21D; B21D53/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49616; Y10T29/4962; Y10T29/51; Y10T29/5116; Y10T83/00; Y10T83/444; Y10T83/4594
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1938-02-11 | 1938-08-13 | 1939-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-02-11 | 1942-08-13 | 1943-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-02-11 | 1946-08-13 | 1947-02-12 | $7700.00 | Window Closed / Lapsed |