US1636713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical wave filter
Assignee: AT&T Inc
•
Filing: 1921-09-08
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Granted: 1927-07-26
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Expires: 1941-09-08
Abstract
No abstract record available.
Inventors
- 👤 George C Reier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:59
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/17; H03H7/1741; H03H7/1766; H03H7/0115; H03H7/1775
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) | 1930-07-25 | 1931-01-24 | 1931-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1934-07-25 | 1935-01-24 | 1935-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1938-07-25 | 1939-01-24 | 1939-07-26 | $7700.00 | Window Closed / Lapsed |