Patent US2174254A successfully refreshed from Google Patents.
US2174254A
Expired / Lapsed
US
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Case hardening of glass sheets
Assignee: PPG Industries Inc
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Filing: 1937-03-13
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Granted: 1939-09-26
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Expires: 1957-03-13
Abstract
No abstract record available.
Inventors
- 👤 Lloyd V Black
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:19
CPC Classifications
C; C03; C03B; C03B35/00; C03B35/14; C03B35/20; Y; Y10; Y10S; Y10S294/00; Y10S294/907; Y10T; Y10T24/00; Y10T24/44; Y10T24/44265
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) | 1942-09-25 | 1943-03-27 | 1943-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-09-25 | 1947-03-27 | 1947-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-09-25 | 1951-03-27 | 1951-09-26 | $7700.00 | Window Closed / Lapsed |