US3438853A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of curing hardboard containing wood fibers and portland cement
Assignee: Armstrong World Industries Inc
•
Filing: 1966-02-10
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Granted: 1969-04-15
•
Expires: 1986-02-10
Abstract
No abstract record available.
Inventors
- 👤 Charles Haines Jr
- 👤 Roy R Rothrock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:17
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/02; C04B28/04; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/91
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-04-14 | 1972-10-14 | 1973-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-14 | 1976-10-14 | 1977-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-14 | 1980-10-14 | 1981-04-15 | $7700.00 | Window Closed / Lapsed |