US4569632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Back-skewed fan
Assignee: Bosch Automotive Motor Systems Corp
•
Filing: 1983-11-08
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Granted: 1986-02-11
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Expires: 2003-11-08
Abstract
Abstract A compact, efficient axial flow fan with blades that are rearwardly (i.e., away from the direction of fan rotation) skewed and which are oriented at a pitch ratio which continuously decreases as a function of increasing blade radius along the radially outermost 30% of the blade.
Inventors
- 👤 Leslie M. Gray, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:24
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/38; F04D29/384; F04D29/386; F04D29/325; F04D29/326; Y; Y10; Y10S; Y10S416/00; Y10S416/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
146 words
A cooling fan, means for maintaining said fan in association with a heat exchanger in position to pass cooling air through said heat exchanger, said fan comprising a hub rotatable on an axis, a plurality of plastic blades, each of which extends radially outward from a root region attached to said hub to a tip region, and a cylindrical band extending concentrically around said fan axis, said band connecting said blade tip regions, said blades: (a) being rearwardly skewed away from the direction of fan rotation; and (b) being oriented at a pitch ratio which continually decreases as a function of increasing blade radius along the radially outermost 30% of said blade, said pitch ratio being equal to 2πr/R.tanQ where R is the total fan radius, r is the radius of a given point on the blade and Q is the blade angle at point r.
Claim 2
Dependent Claim
146 words
A cooling fan, means for maintaining said fan in association with a heat exchanger in position to pass cooling air through said heat exchanger, said fan comprising a hub rotatable on an axis, a plurality of plastic blades, each of which extends radially outward from a root region attached to said hub to a tip region, and a cylindrical band extending concentrically around said fan axis, said band connecting said blade tip regions, said blades: (a) being rearwardly skewed away from the direction of fan rotation; and (b) being oriented at a pitch ratio which continually decreases as a function of increasing blade radius along the radially outermost 30% of said blade, said pitch ratio being equal to 2πr/R.tanQ where R is the total fan radius, r is the radius of a given point on the blade and Q is the blade angle at point r.
Claim 3
Dependent Claim
19 words
The fan of claim 1 wherein the blade skew angle (T) is at least 50 degrees at said tip.
Claim 4
Dependent Claim
22 words
The fan of claim 1 wherein the blade skew angle (T) is at least 25 degrees at a non-dimensional radius of 0.70.
Claim 5
Dependent Claim
37 words
The fan of claim 1 wherein said means for maintaining said fan in association with a heat exchanger is a means for positioning said fan upstream from said heat exchanger to blow air through said heat exchanger.
Claim 6
Dependent Claim
14 words
The fan of claim 1 wherein said fan comprises at least four said blades.
Claim 7
Dependent Claim
23 words
The fan of claim 1 wherein the skew angle increases continually along the segment of the blade where r/R is greater than 0.7.
Claim 8
Dependent Claim
15 words
The fan according to claim 1 wherein said fan is formed as an integral structure.
Claim 9
Dependent Claim
17 words
The fan according to claim 1 wherein said integral structure is formed of a molded plastic material.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-10 | 1989-08-12 | 1990-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-10 | 1993-08-12 | 1994-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-10 | 1997-08-12 | 1998-02-11 | $7700.00 | Window Closed / Lapsed |