Ventilation – Electronic cabinet
Reexamination Certificate
1999-05-25
2001-06-12
Joyce, Harold (Department: 3749)
Ventilation
Electronic cabinet
C361S695000
Reexamination Certificate
active
06244953
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the mounting of fans in a chassis or other structure associated with an electronic device and more particularly to electronic devices having a housing with electronic components therein and having space for a cooling fan.
BACKGROUND OF THE INVENTION
Electronic devices often include one or more fans for cooling the interior space of the housing and the electronic components disposed in the housing. Particularly with computers, network systems and other devices with electronic components, the cooling of the system components is critical to the adequate function and performance of the device. Especially with devices operating at high speeds, fans are necessary for the proper operation of the device.
Often the housing or chassis of the electronic device is made from sheet steel or other sheet metal. One or more openings are provided in the housing to allow air to flow through the housing for cooling purposes. A fan assembly for a fan module or unit is positioned within the housing adjacent to the opening. The fan assembly must be secured to the chassis and preferably, the fan assembly should be removable, in case of a failure of the fan.
Various different arrangements have been provided for fixing the fan in its position. Screws and other mechanical fasteners have been used. Adhesive products may also be used.
Various fan structures have been used in the computer and network device fields. These structures often are provided as modules. The modules or units include a housing or enclosure as well as the fan apparatus. 40 mm fan units or fan modules with a 1u (1 equipment rack unit equivalent to 1.75 inch.) enclosures are often used in network applications such as for local area network hubs and concentrators. The enclosures may also be of another size (e.g., 2u, etc).
Often in both computer and network applications multiple fan units are provided. Multiple units provide some assurance as to the continued provision of cooling air flow, even if one of the units stops working. The units must nevertheless be changed to provide optimal cooling for the device.
Both the installation and the changing of fans or fan units, presents significant difficulties. As to the installation, the use of mechanical fasteners and/or adhesive backed tape, to retain the fan unit, is problematic and adds costs to the overall assembly. Further, if mechanical fasteners or adhesive backed tape are used or other fixing structure, it must be used such that it is possible to easily and efficiently take out the fan unit and replace it with a new one, in the case of fan failure.
SUMMARY AND OBJECTS OF THE INVENTION
It is a primary object of the invention to provide a fan mounting arrangement for mounting fans to move cooling air through an electronic device enclosure, without the use of fasteners or secondary manufacturing processes.
It is a further object of the invention to provide a fan assembly and a fan and chassis mounting arrangement which allows the fan to be positioned and secured relative to the housing or chassis but also allows for the replacement and removal of the fan without disturbing neighboring components in the assembled chassis.
It is a further object of the invention to provide a fan and chassis assembly including a fan mounting bracket which receives a fan unit such as a
40
mm fan unit and which can be secured to the chassis wherein the securing features are fully provided in the fan bracket and in a chassis piece and wherein the fan bracket is formed of a single sheet metal piece and the chassis part is formed of a single sheet metal piece.
According to the invention, a fan and chassis mounting arrangement is provided including a fan unit, a chassis portion and bracket. The chassis has an air flow opening in the region of a fan bracket receiving space. The fan bracket defines a fan receiving space and has a fan retention system for holding a fan in the fan space. The fan unit may include a fan housing and the fan retention system includes a basket structure with substantially vertically extending surfaces for engaging the fan housing. The substantially vertically extending surfaces are flexibly movable relative to a remainder of the bracket to facilitate insertion of the fan housing.
The chassis portion and bracket may be formed of sheet metal or plastic or other materials. The chassis portion and bracket may be provided as one integral piece or may include separate bracket and chassis portions. These are preferably connected with a bracket retention system including a chassis bracket retention element integrally defined in the chassis, at a location adjacent to the fan bracket receiving space, and a bracket retention element integrally defined in said bracket. The connection is without added fasteners and without secondary assembly operations (also no tools are needed). The chassis bracket retention element has a shape cooperating with a shape of the bracket retention element. The bracket is retained in the chassis by cooperation between the chassis fan bracket retention element and the bracket retention element and without the use of a separate discrete fastening element.
The fan retention system may include dull metal barbs extending from the bracket into receiving openings formed in said fan housing. A flexing movement of the substantially vertically extending surfaces facilitates the establishment of an interference fit between the fan housing and the bracket (via the dull metal barbs).
The basket structure preferably includes a basket bottom and the substantially vertically extending surfaces include side tabs bent with respect to a surface of said basket bottom and one or more front tabs bent with respect to a surface of the basket bottom. At least one of the side tabs includes a bent angled portion defining a receiving surface. The basket bottom provides a bent flange which avoids relative vibrations at the basket and chassis interface at a bottom of the chassis.
The substantially vertically extending surfaces include surfaces defining opposed frictional securing surfaces with a another surface of the bracket. The opposed frictional surface is advantageously a front surface of a plenum defining bracket part.
The substantially vertically extending surfaces include surfaces defining opposed guiding surfaces. These facilitate the insertion of the fan and the removal of the fan.
The bracket preferably includes a portion defining a plenum chamber. The portion may have a front surface defining a fan engaging surface disposed opposite at least one of the substantially vertically extending surfaces.
The chassis retention element preferably includes one of a protruding portion and a recess portion formed in the chassis. The bracket retention element includes either a hole or one of a protruding portion and a recess portion formed in the bracket. The bracket retention element cooperates with the chassis retention element.
The bracket retention system further preferably includes side flanges forming a part of the bracket and receiving slot flanges forming a part of the chassis. The receiving slot flanges each receive an associated one of the side flanges. The bracket retention element is provided on one of said flanges and the chassis bracket retention element is provided adjacent to one of said receiving slot flanges.
The chassis bracket retention element is preferably formed of the same single sheet metal piece that forms said opening.
According to the invention, a fan and chassis assembly is also provided. The assembly includes a fan, a bracket and a chassis. The fan includes a fan housing having an outer periphery. The chassis includes a sheet metal piece having an air flow opening in the region of a fan bracket receiving space. The bracket is a sheet metal fan bracket defining a fan housing receiving space and having integral fan retention elements engaging the fan housing periphery and for holding the fan in a position in the fan space. The bracket retention elements are integrally formed in the chassis and in the fan brac
Anderson Scott David
Dugan John Francis
3Com Corporation
Joyce Harold
McGlew and Tuttle , P.C.
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