Patent US2619831A successfully refreshed from Google Patents.
US2619831A
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US
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Hardness tester as a function of time
Assignee: FKI Industries Inc
•
Filing: 1946-03-05
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Granted: 1952-12-02
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Expires: 1966-03-05
Abstract
No abstract record available.
Inventors
- 👤 David F Sklar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:57
CPC Classifications
G; G01; G01N; G01N3/00; G01N3/40; G01N3/42; G01N3/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US989411A
Cited
GB191026574A
Cited
US1225438A
Cited
US1771858A
Cited
US1762497A
Cited
US1839093A
Cited
US1931925A
Cited
US2053472A
Cited
US2129043A
Cited
FR806039A
Cited
DE700521C
Cited
US2259491A
Cited
US2316975A
Cited
US2319208A
Cited
US2333747A
Cited
US2375341A
Cited
US2426390A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-12-02 | 1956-06-02 | 1956-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-12-02 | 1960-06-02 | 1960-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-12-02 | 1964-06-02 | 1964-12-02 | $7700.00 | Window Closed / Lapsed |