US4120609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sheet metal fan
Assignee: Schwitzer US Inc
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Filing: 1976-06-14
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Granted: 1978-10-17
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Expires: 1996-06-14
Abstract
Abstract A sheet metal fan blade of improved performance and efficiency has a varying camber angle and chord angle along radial positions of the blade, such that the angle of attack along at least 70% of the length of the blade is not less than 2° or more than 10°. The fan blade construction exhibits utility in an automotive radiator cooling system.
Inventors
- 👤 Cheng-Chien Chou
- 👤 Clifford Sau Leong Yee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:48
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/38; F04D29/384; Y; Y10; Y10S; Y10S416/00; Y10S416/03
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
189 words
A rotating fan comprising, in combination: (a) a hub secured to and rotated by a rotary shaft; (b) a plurality of sheet metal fan blades fixed in spaced circumferential relation to said hub and projecting radially therefrom; each fan blade having a leading edge and a trailing edge defining a chord length C therebetween, and a forming radius of curvature at each radial station r which establishes with said chord length C a camber angle θ and a chord angle γ at each such station; and each fan blade having its chord angle and its camber angle varied over its radial length such that the theoretical energy transfer ΔH TH per unit mass of air at each radial station r is equal to K H (r N ) over at least 70% of its radial length, where n is a constant greater than 1 but less than 2 and ##EQU10## in which: ρ = density of air r i = fan blade inner radius r o = fan blade outer radius Δp = average pressure rise across the fan η oa = overall fan efficiency g = gravitational acceleration.
Claim 2
Dependent Claim
189 words
A rotating fan comprising, in combination: (a) a hub secured to and rotated by a rotary shaft; (b) a plurality of sheet metal fan blades fixed in spaced circumferential relation to said hub and projecting radially therefrom; each fan blade having a leading edge and a trailing edge defining a chord length C therebetween, and a forming radius of curvature at each radial station r which establishes with said chord length C a camber angle θ and a chord angle γ at each such station; and each fan blade having its chord angle and its camber angle varied over its radial length such that the theoretical energy transfer ΔH TH per unit mass of air at each radial station r is equal to K H (r N ) over at least 70% of its radial length, where n is a constant greater than 1 but less than 2 and ##EQU10## in which: ρ = density of air r i = fan blade inner radius r o = fan blade outer radius Δp = average pressure rise across the fan η oa = overall fan efficiency g = gravitational acceleration.
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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) | 1981-10-16 | 1982-04-17 | 1982-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-16 | 1986-04-17 | 1986-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-16 | 1990-04-17 | 1990-10-17 | $7700.00 | Window Closed / Lapsed |