Patent US2835784A successfully refreshed from Google Patents.
US2835784A
Expired / Lapsed
US
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Spark machining apparatus
Assignee: Firth Sterling Inc
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Filing: 1954-07-21
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Granted: 1958-05-20
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Expires: 1974-07-21
Abstract
No abstract record available.
Inventors
- 👤 Everard M Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:22
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/022
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2310092A
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US2235385A
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US2287543A
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US2501954A
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CH257468A
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US2552582A
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US2697160A
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US2628330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-05-19 | 1961-11-18 | 1962-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-05-19 | 1965-11-18 | 1966-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-05-19 | 1969-11-18 | 1970-05-20 | $7700.00 | Window Closed / Lapsed |