Patent US1868607A successfully refreshed from Google Patents.
US1868607A
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US
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Electromagnetic sound reproducer system
Assignee: Federal Telegraph Co
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Filing: 1928-08-16
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Granted: 1932-07-26
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Expires: 1948-08-16
Abstract
No abstract record available.
Inventors
- 👤 Frederick A Kolster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:28
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/24
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) | 1935-07-26 | 1936-01-25 | 1936-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1939-07-26 | 1940-01-25 | 1940-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1943-07-26 | 1944-01-25 | 1944-07-26 | $7700.00 | Window Closed / Lapsed |