Patent US3521704A successfully refreshed from Google Patents.
US3521704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanger for recreational vehicle
Assignee: Individual
•
Filing: 1968-07-22
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Granted: 1970-07-28
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Expires: 1988-07-22
Abstract
No abstract record available.
Inventors
- 👤 James Earl Bridegum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:19
CPC Classifications
F; F28; F28D; F28D19/00; B; B60; B60P; B60P3/00; B60P3/32; B60P3/36; F24; F24D; F24D17/00; F24D17/0005; F24D17/001; G; G01; G01M; G01M3/00; Y; Y02; Y02B; Y02B30/00; Y02B30/18
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) | 1973-07-27 | 1974-01-26 | 1974-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-27 | 1978-01-26 | 1978-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-27 | 1982-01-26 | 1982-07-28 | $7700.00 | Window Closed / Lapsed |