US2177769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loud-speaking intercommunicating system
Assignee: FRANK I DU FRANE Co Inc
•
Filing: 1938-12-24
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Granted: 1939-10-31
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Expires: 1958-12-24
Abstract
No abstract record available.
Inventors
- 👤 Lennart G Erickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:24
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/001
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) | 1942-10-30 | 1943-05-01 | 1943-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-10-30 | 1947-05-01 | 1947-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-10-30 | 1951-05-01 | 1951-10-31 | $7700.00 | Window Closed / Lapsed |