Patent US3435839A successfully refreshed from Google Patents.
US3435839A
Expired / Lapsed
US
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Backflow bypassing valve for breathing apparatus
Assignee: Elder Oxygen Co Inc
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Filing: 1965-05-21
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Granted: 1969-04-01
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Expires: 1985-05-21
Abstract
No abstract record available.
Inventors
- 👤 David Elder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:51
CPC Classifications
A; A62; A62B; A62B9/00; A62B9/02; A61; A61M; A61M16/00; A61M16/20; A61M16/208; A61M16/209; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544; Y10T137/7722; Y10T137/7837; Y10T137/7838; Y10T137/7841
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2876785A
Cited
US3083707A
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US2887104A
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US3242921A
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US2954793A
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US2947314A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-03-31 | 1972-09-30 | 1973-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-03-31 | 1976-09-30 | 1977-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-03-31 | 1980-09-30 | 1981-04-01 | $7700.00 | Window Closed / Lapsed |