US2868947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark machining apparatus
Assignee: FIRTH STIRLING Inc
•
Filing: 1956-04-20
•
Granted: 1959-01-13
•
Expires: 1976-04-20
Abstract
No abstract record available.
Inventors
- 👤 Everard M Williams
- 👤 Porterfield Cecil Paul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:19
CPC Classifications
B; B23; B23H; B23H1/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
GB420100A
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US2179105A
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US2147472A
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GB519353A
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US2235385A
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US2295293A
Cited
GB637793A
Cited
US2526423A
Cited
FR1048972A
Cited
US2719902A
Cited
FR1108192A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-01-12 | 1962-07-14 | 1963-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-01-12 | 1966-07-14 | 1967-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-01-12 | 1970-07-14 | 1971-01-13 | $7700.00 | Window Closed / Lapsed |