Patent US2169818A successfully refreshed from Google Patents.
US2169818A
Expired / Lapsed
US
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Spark generating system
Assignee: —
•
Filing: —
•
Granted: 1939-08-15
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Expires: 1956-08-15
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:29
CPC Classifications
F; F02; F02B; F02B75/00; F02B75/16; F02B75/18; F02B75/22; F02B75/222; F02B2075/1804; F02B2075/1856
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) | 1942-08-14 | 1943-02-13 | 1943-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-08-14 | 1947-02-13 | 1947-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-08-14 | 1951-02-13 | 1951-08-15 | $7700.00 | Window Closed / Lapsed |