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Patent US2820469A successfully refreshed from Google Patents.
US2820469A
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US
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Combined compensated inhalationexhalation valve for pressure breathing mask
Assignee: Individual
•
Filing: 1955-11-29
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Granted: 1958-01-21
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Expires: 1975-11-29
Abstract
No abstract record available.
Inventors
- 👤 Henry W Seeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:55
CPC Classifications
A; A62; A62B; A62B9/00; A62B9/02; Y; Y10; Y10S; Y10S137/00; Y10S137/908; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7838; Y10T137/7841
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2409327A
Cited
US2615463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-01-20 | 1961-07-22 | 1962-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-01-20 | 1965-07-22 | 1966-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-01-20 | 1969-07-22 | 1970-01-21 | $7700.00 | Window Closed / Lapsed |