Patent US3697366A successfully refreshed from Google Patents.
US3697366A
Expired / Lapsed
US
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Lightweight gypsum panel
Assignee: National Gypsum Co
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Filing: 1970-04-13
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Granted: 1972-10-10
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Expires: 1990-04-13
Abstract
Abstract GYPSUM WALLBOARD IN WHICH ABOUT HALF THE VOLUME OF THE CORE CONSISTS OF VERY LIGHTWEIGHT PARTICLES FORMED BY TEARING FOAMED POLYSTYRENE BEADS INTO A SHREDDED FORM.
Inventors
- 👤 George H Harlock
- 👤 Edward A Burkard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:24
CPC Classifications
B; B28; B28B; B28B23/00; B28B23/0081; B28B23/0087; C; C04; C04B; C04B16/00; C04B16/04; C04B16/08; C04B16/087; Y; Y10; Y10S; Y10S264/00; Y10S264/07; Y10S521/00; Y10S521/921; Y10T; Y10T428/00; Y10T428/26; Y10T428/268; Y10T428/27
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |