Patent US3639078A successfully refreshed from Google Patents.
US3639078A
Expired / Lapsed
US
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Flexible-bladed fan with extended blade structure
Assignee: Siemens Bendix Automotive Electronics Ltd
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Filing: 1970-11-04
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Granted: 1972-02-01
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Expires: 1990-11-04
Abstract
Abstract A fan having a hub, a plurality of arms each extending radially outwardly of the hub and at an acute angle to the rotational plane of the fan, and blade structures, one secured to each arm, each blade structure having a flexible, resilient trailing airfoil portion, comprising the major portion of the blade structure, which decambers as rotational speed increases, and a less flexible leading airfoil portion comprising a slat extending forward of the respective arm and disposed at an angle thereto lying within the above specified acute angle, with the trailing and leading portions mutually constructed to have the leading and trailing edges of the blade define therebetween a chord disposed at a predetermined chord angle to the rotational plane of the fan.
Inventors
- 👤 Shrinivas V Pratinidhi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:19
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/38; F04D29/382
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
170 words
In a fan having a hub, a plurality of arms projecting radially outwardly of said hub, and blade structures secured to said arms, said blade structures each comprising a flexible, resilient trailing portion, defining an airfoil surface terminating in the trailing edge of said blade structure, which decambers as rotational speed increases, the plane of each said arm being disposed at an acute angle to the rotational plane of said fan, the improvement wherein each said blade structure also comprises a leading portion, less flexible than said trailing portion, extending forward of the arm to which it is secured and effectively disposed at an angle to the plane thereof lying within said acute angle, said leading portion comprising a slat defining an extended airfoil surface terminating in the leading edge of said blade structure, said trailing portion comprising the major portion of said blade structure and said leading edge and said trailing edge defining therebetween a chord disposed at a predetermined chord angle to the rotational plane of said fan.
Claim 2
Dependent Claim
170 words
In a fan having a hub, a plurality of arms projecting radially outwardly of said hub, and blade structures secured to said arms, said blade structures each comprising a flexible, resilient trailing portion, defining an airfoil surface terminating in the trailing edge of said blade structure, which decambers as rotational speed increases, the plane of each said arm being disposed at an acute angle to the rotational plane of said fan, the improvement wherein each said blade structure also comprises a leading portion, less flexible than said trailing portion, extending forward of the arm to which it is secured and effectively disposed at an angle to the plane thereof lying within said acute angle, said leading portion comprising a slat defining an extended airfoil surface terminating in the leading edge of said blade structure, said trailing portion comprising the major portion of said blade structure and said leading edge and said trailing edge defining therebetween a chord disposed at a predetermined chord angle to the rotational plane of said fan.
Claim 3
Dependent Claim
26 words
The fan of claim 1 wherein said predetermined chord angle is between about 25* and about 35* when said blade structure is in an unbiased position.
Claim 4
Dependent Claim
13 words
The fan of claim 2 wherein said chord angle is about 32* .
Claim 5
Dependent Claim
36 words
The fan of claim 2 wherein said leading edge and said trailing edge are substantially parallel to one another to define therebetween a plane disposed at said chord angle to the rotational plane of said fan.
Claim 6
Dependent Claim
20 words
The fan of claim 1 wherein said leading portion is composed of a more rigid material than said trailing portion.
Claim 7
Dependent Claim
29 words
The fan of claim 1 wherein said leading edge and said trailing edge are located, respectively, on opposite sides of the rotational plane of the hub of said fan.
Claim 8
Dependent Claim
24 words
The fan of claim 1 wherein said angle between said leading portion and the plane of said arm is less than about 20* .
Claim 9
Dependent Claim
22 words
The fan of claim 7 wherein said angle between said leading portion and the plane of said arm is about 15* .
Claim 10
Dependent Claim
43 words
The fan of claim 1 wherein each said blade structure comprises a flexible, resilient trailing member including said trailing portion and a separate leading member including said leading portion, and said members are arranged to overlap one another where secured to said arm.
Claim 11
Dependent Claim
52 words
The fan of claim 9 including a separate reinforcing cap overlaying the convex side of each said blade structure, and wherein said members overlap between said reinforcing cap and said arm, and are secured therebetween with said trailing member sandwiched between said reinforcing cap and the overlapping portion of said leading member.
Claim 12
Dependent Claim
54 words
The fan of claim 10 wherein said members extend radially beyond said arm and said reinforcing can extends radially coextensively with the one of said members sandwiched against said arm and is secured to said blade structure at a point radially outwardly of said arm adjacent the end of said one of said members.
Claim 13
Dependent Claim
31 words
The fan of claim 9 wherein said trailing member extends forward of said arm and is disposed adjacent said leading member, and said leading member extends forward of said trailing member.
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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) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |