US3428476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing hydrogen diffusion cells
Assignee: Engelhard Minerals and Chemicals Corp
•
Filing: 1965-06-22
•
Granted: 1969-02-18
•
Expires: 1985-06-22
Abstract
No abstract record available.
Inventors
- 👤 Robert C Langley
- 👤 Herbert Myers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:56
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/52; C04B41/80; C04B41/81; C04B41/89; C23; C23C; C23C26/00; H; H01; H01M; H01M4/00; H01M4/86; H01M4/94; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
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) | 1972-02-18 | 1972-08-19 | 1973-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-02-18 | 1976-08-19 | 1977-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-02-18 | 1980-08-19 | 1981-02-18 | $7700.00 | Window Closed / Lapsed |