US5052888A
Expired / Lapsed
US
⏱️ 0.0 years remaining
DC motor driven centrifugal fan
Assignee: International Business Machines Corp
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Filing: 1990-07-11
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Granted: 1991-10-01
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Expires: 2010-07-11
Abstract
Abstract A centrifugal fan includes a brushless d.c. motor, an impeller mounted on the motor and a scroll on which the motor is mounted. The scroll defines the air inlet and outlet and has an outer wall curved around the impeller to define a divergent air flow path. By truncating the scroll at the outlet substantially to eliminate any flat portions on the outer wall susceptible to mechanical vibrations at frequencies excited by the d.c. motor, a noise reduction is achieved. Further noise reduction may be achieved by resiliently mounting the motor on the scroll.
Inventors
- 👤 Ivor W. Bolton
- 👤 David S. Gaunt
- 👤 Ronald K. Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:09
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/66; F04D29/661; F04D29/668; F04D29/40; F04D29/42; F04D29/4206; F04D29/4226; F04D29/424
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A centrifugal fan comprising: a brushless direct current motor; an impeller mounted on said brushless direct current motor for rotation thereby; and a scroll for mounting said brushless direct current motor, said scroll defining an air inlet, an air outlet and including an outer wall curved around said impeller to define a divergent path to said air outlet for air driven by said impeller, said scroll being truncated at said air outlet so as to form a plane at said air outlet which is substantially orthogonal to a radius of said scroll.
Claim 2
Dependent Claim
92 words
A centrifugal fan comprising: a brushless direct current motor; an impeller mounted on said brushless direct current motor for rotation thereby; and a scroll for mounting said brushless direct current motor, said scroll defining an air inlet, an air outlet and including an outer wall curved around said impeller to define a divergent path to said air outlet for air driven by said impeller, said scroll being truncated at said air outlet so as to form a plane at said air outlet which is substantially orthogonal to a radius of said scroll.
Claim 3
Dependent Claim
18 words
The centrifugal fan according to claim 1, in which said outer wall of said scroll is completely curved.
Claim 4
Dependent Claim
35 words
The centrifugal fan according to claim 1, wherein said air outlet includes a substantially rectangular aperture and wherein said scroll includes coplanar flanges extending outwardly from said substantially rectangular aperture for mounting said centrifugal fan.
Claim 5
Dependent Claim
26 words
The centrifugal fan according to claim 1, wherein said scroll includes two sidewalls, each of said two sidewalls including an aperture to provide an air inlet.
Claim 6
Dependent Claim
20 words
The centrifugal fan according to claim 1, in which said brushless direct current motor is resiliently mounted on said scroll.
Claim 7
Dependent Claim
43 words
The centrifugal fan according to claim 5, wherein said scroll includes a sidewall and said centrifugal fan includes a motor support frame resiliently connected to said sidewall and extending axially into said scroll, within said impeller, to support said brushless direct current motor.
Claim 8
Dependent Claim
57 words
The centrifugal fan according to claim 6, wherein said motor support frame includes an outer plate, co-extensive with said sidewall, and a cage portion extending axially into said scroll and rigidly connected to said brushless direct current motor, said resilient connection provided by a plurality of circumferentially disposed vibration isolators between said outer plate and said sidewall.
Claim 9
Dependent Claim
44 words
The centrifugal fan according to claim 7, wherein said sidewall includes an aperture to provide an air inlet and wherein said outer plate of said motor support frame is annular in shape so as to minimize obstruction of said air inlet within said sidewall.
Claim 10
Dependent Claim
22 words
The centrifugal fan according to claim 7, wherein said motor support frame is made of an elastomeric material to provide vibration isolation.
Claim 11
Dependent Claim
27 words
The centrifugal fan according to claim 7, in which said motor support frame comprises three legs connecting a base portion to respective feet disposed within said sidewall.
Claim 12
Dependent Claim
26 words
The centrifugal fan according to claim 10, in wherein each of said legs is reduced in thickness adjacent said respective feet to provide further vibration isolation.
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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) | 1994-09-30 | 1995-04-01 | 1995-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-30 | 1999-04-01 | 1999-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-30 | 2003-04-01 | 2003-10-01 | $7700.00 | Window Closed / Lapsed |