Patent US2660916A successfully refreshed from Google Patents.
US2660916A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Test equipment for measuring the flatness and plane parallelism of glass surfaces ofany desired size and thickness by light wave interference
Assignee: Individual
•
Filing: 1950-07-25
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Granted: 1953-12-01
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Expires: 1970-07-25
Abstract
No abstract record available.
Inventors
- 👤 Theodor W Zobel
- 👤 Mirus Ferdinand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:41
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2253054A
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US2410502A
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US2472991A
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US2312888A
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GB569046A
Cited
US2452364A
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US2378930A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-11-30 | 1957-06-01 | 1957-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-11-30 | 1961-06-01 | 1961-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-11-30 | 1965-06-01 | 1965-12-01 | $7700.00 | Window Closed / Lapsed |