US3520708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of calcium sulphate hemihydrate
Assignee: Berk Ltd
•
Filing: 1966-12-12
•
Granted: 1970-07-14
•
Expires: 1986-12-12
Abstract
No abstract record available.
Inventors
- 👤 Geoffrey Prytherch Ca Chambers
- 👤 Michael Robert Damm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:15
CPC Classifications
C; C04; C04B; C04B11/00; C04B11/02; C04B11/024
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) | 1973-07-13 | 1974-01-12 | 1974-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-13 | 1978-01-12 | 1978-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-13 | 1982-01-12 | 1982-07-14 | $7700.00 | Window Closed / Lapsed |