Patent US3217808A successfully refreshed from Google Patents.
US3217808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cooling fans
Assignee: Dowty Hydraulic Units Ltd
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Filing: 1964-09-28
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Granted: 1965-11-16
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Expires: 1984-09-28
Abstract
No abstract record available.
Inventors
- 👤 Arthur E H Elmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:50
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/34; F04D29/36; F04D29/362; F04D29/366; F01; F01P; F01P7/00; F01P7/02; F01P7/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
179 words
A FAN FOR COOLING THE ENGINE OF AN AUTOMOTIVE VEHICLE, AT SUBSTANTIALLY CONSTANT VOLUME AIR FLOW REGARDLESS OF THE SPEED OF THE VEHICLE OR THE CORRESPONDING ROTATIONAL SPEED OF THE FAN, SAID FAN BEING ARRANGED TO BE DRIVEN BY THE ENGINE, AND COMPRISING, IN COMBINATION: (A) A HUB ROTATIVE AT A SPEED CORRESPONDING TO THE ENGINE''S SPEED, (B) A PLURALITY OF BLADES DISTRIBUTED ABOUT THE HUB AND EACH MOUNTED THEREON FOR PIVOTAL MOVEMENT ABOUT A RADIALLY DIRECTED PITCH-CHANGE AXIS, (C) SPRING MEANS REACTING BETWEEN THE HUB AND THE BLADES TO BIAS EACH BLADE TOWARDS A COARSE-PITCH POSITION, AND YIELDABLY RESISTING THEIR TWISTING ABOUT THEIR AXIS TOWARDS A FINE-PITCH POSITION UNDER THE INFLUENCE OF INHERENT CENTRIFUGAL TWISTING MOMENTS THAT INCREASE WITH INCREASE IN ROTATIONAL SPEED OF THE HUB, AND (D) SUPPLEMENTARY PITCH-ADJUSTING MEANS OPERABLE AT RELATIVELY HIGH SPEEDS OF THE VEHICLE AND CONSEQUENT RELATIVELY HIGH ROTATIONAL SPEEDS OF THE FAN, TO SUPPLEMENT THE EFFECT OF THE INHERENT CENTRIFUGAL TWISTING MOMENTS, AND THEREBY TO MAINTAIN THE VOLUME OF AIR PASSING THROUGH THE FAN SUBSTANTIALLY CONSTANT THROUGHOUT THE FAN''S ROTATIONAL SPEED RANGE.
Claim 2
Dependent Claim
179 words
A FAN FOR COOLING THE ENGINE OF AN AUTOMOTIVE VEHICLE, AT SUBSTANTIALLY CONSTANT VOLUME AIR FLOW REGARDLESS OF THE SPEED OF THE VEHICLE OR THE CORRESPONDING ROTATIONAL SPEED OF THE FAN, SAID FAN BEING ARRANGED TO BE DRIVEN BY THE ENGINE, AND COMPRISING, IN COMBINATION: (A) A HUB ROTATIVE AT A SPEED CORRESPONDING TO THE ENGINE''S SPEED, (B) A PLURALITY OF BLADES DISTRIBUTED ABOUT THE HUB AND EACH MOUNTED THEREON FOR PIVOTAL MOVEMENT ABOUT A RADIALLY DIRECTED PITCH-CHANGE AXIS, (C) SPRING MEANS REACTING BETWEEN THE HUB AND THE BLADES TO BIAS EACH BLADE TOWARDS A COARSE-PITCH POSITION, AND YIELDABLY RESISTING THEIR TWISTING ABOUT THEIR AXIS TOWARDS A FINE-PITCH POSITION UNDER THE INFLUENCE OF INHERENT CENTRIFUGAL TWISTING MOMENTS THAT INCREASE WITH INCREASE IN ROTATIONAL SPEED OF THE HUB, AND (D) SUPPLEMENTARY PITCH-ADJUSTING MEANS OPERABLE AT RELATIVELY HIGH SPEEDS OF THE VEHICLE AND CONSEQUENT RELATIVELY HIGH ROTATIONAL SPEEDS OF THE FAN, TO SUPPLEMENT THE EFFECT OF THE INHERENT CENTRIFUGAL TWISTING MOMENTS, AND THEREBY TO MAINTAIN THE VOLUME OF AIR PASSING THROUGH THE FAN SUBSTANTIALLY CONSTANT THROUGHOUT THE FAN''S ROTATIONAL SPEED RANGE.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-11-15 | 1969-05-17 | 1969-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-11-15 | 1973-05-17 | 1973-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-11-15 | 1977-05-17 | 1977-11-16 | $7700.00 | Window Closed / Lapsed |