Patent US2449683A successfully refreshed from Google Patents.
US2449683A
Expired / Lapsed
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Differential pressure valve
Assignee: Individual
•
Filing: 1943-04-16
•
Granted: 1948-09-21
•
Expires: 1963-04-16
Abstract
No abstract record available.
Inventors
- 👤 John D Akerman
- 👤 Schonberg Mihkel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:11
CPC Classifications
F; F16; F16K; F16K15/00; F16K15/20; F16K15/02; F16K15/025; F16K15/026; F16K15/028; Y; Y10; Y10S; Y10S33/00; Y10S33/06; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7904; Y10T137/7922; Y10T137/7929; Y10T137/7938
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) | 1951-09-21 | 1952-03-22 | 1952-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-09-21 | 1956-03-22 | 1956-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-09-21 | 1960-03-22 | 1960-09-21 | $7700.00 | Window Closed / Lapsed |