US2835447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnace control system with dual speed blower
Assignee: WILLIAMSON Co
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Filing: 1953-11-06
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Granted: 1958-05-20
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Expires: 1973-11-06
Abstract
No abstract record available.
Inventors
- 👤 William H Calahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:07
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/275; G05D23/27535; G05D23/2754; F; F24; F24D; F24D5/00; F24D5/02; F24D5/04
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) | 1961-05-19 | 1961-11-18 | 1962-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-05-19 | 1965-11-18 | 1966-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-05-19 | 1969-11-18 | 1970-05-20 | $7700.00 | Window Closed / Lapsed |