US2440187A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractory and method of making the same
Assignee: American Optical Corp
•
Filing: 1943-01-16
•
Granted: 1948-04-20
•
Expires: 1963-01-16
Abstract
No abstract record available.
Inventors
- 👤 Carl G Silverberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:53
CPC Classifications
C; C04; C04B; C04B33/00; C04B33/02; C04B33/13; C04B33/1305; Y; Y10; Y10S; Y10S65/00; Y10S65/04
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-04-20 | 1951-10-20 | 1952-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-04-20 | 1955-10-20 | 1956-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-04-20 | 1959-10-20 | 1960-04-20 | $7700.00 | Window Closed / Lapsed |