Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-11-12
2001-08-07
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S802000, C361S756000, C174S034000, C174S051000
Reexamination Certificate
active
06272022
ABSTRACT:
BACKGROUND OF THE INVENTION
Electronic equipment, particularly in the field of telecommunications, is generally housed within a chassis which is positioned on a shelf within a rack. The equipment such as, for example, switch mode rectifiers may generate undesirable heat, and therefore fans are required to be installed within the chassis to dissipate excessive heat buildup. Periodically, the fans must be replaced due to a limited life cycle of fan rotor bearings. Replacement of fans must be done in the field to minimize the time in which the rectifier is out of service. Field replacement therefore must be accomplished quickly and with a minimal effort on behalf of an installer to access and replace the fan assembly. A reduction in the number of screws mounting the fan assembly to the chassis helps achieve this goal. However, minimizing the number of screws or fasteners attaching the fan assembly to the chassis results in long lengths of overlapping metal seams between the fan assembly bracket and chassis. The fan assembly bracket and chassis interface becomes a major source of electromagnetic interface (EMI) emissions which are generated by the rectifier, especially in the case of high frequency switching power supplies. Typically, in switch mode rectifiers, a desired maximum seam length between fasteners is two inches, therefore, minimizing the number of fasteners which creates longer seams is not consistent with the goal of minimizing EMI emissions.
EMI emissions can be reduced by utilizing a gasket strip attached to the chassis to ensure good metal to metal contact between the chassis and fan assembly bracket, or additional grounding screws can be added to attach the fan assembly bracket to the chassis. However, the elimination of screws and not the addition of screws is desirable to minimize the effort to replace a fan in the field. Gaskets are costly and further add to the time required to replace a fan in the field.
A need has thus arisen for a fan assembly bracket which allows for easy replacement of the fan in the field while providing for enhanced EMI performance. Such a bracket must provide for easy access to the fan for fan replacement and reinstallation with a minimum number of screws to decrease installation time while providing for good metal to metal contact between the fan assembly bracket and chassis to minimize EMI emissions.
SUMMARY OF THE INVENTION
In accordance with the present invention, a housing for a switch mode rectifier is provided. The housing includes an enclosure having front and rear panels, top and bottom walls, and side walls. A bracket is attached to the enclosure and includes a plurality of projections for mating with a plurality of apertures contained in one or more of the walls of the enclosure. The projections are larger than the apertures, such that when pressure is applied to the bracket, the projections are forced into the apertures to form a seal to minimize EMI emissions from the enclosure.
In accordance with another aspect of the present invention, a bracket for removably mounting a fan to a housing is provided. The bracket includes a frame for receiving a fan. The frame includes a plurality of projections adapted to mate with apertures contained in two of the walls of the housing. The mating projections and apertures form a seal between the fan frame and the wall of the housing when pressure is applied to the frame. The seal minimizes EMI emissions from the housing.
In accordance with another aspect of the present invention, a system for reducing electromagnetic interference emissions is provided. The system includes a housing. A switch mode rectifier is mounted within the housing. A fan is further mounted to the housing utilizing a bracket for removably mounting the fan to the housing. Two of the housing walls includes a plurality of apertures. The bracket includes a plurality of projections adapted to mate with the apertures in the wall of the housing. The projections are larger than the apertures, such that when pressure is applied to the bracket, the projections are forced into the apertures to form a seal to thereby minimize EMI emissions from the housing.
REFERENCES:
patent: 4356531 (1982-10-01), Marino et al.
patent: 4759466 (1988-07-01), Chase et al.
patent: 4780570 (1988-10-01), Chuck
patent: 5673029 (1997-09-01), Behl et al.
patent: 5788566 (1998-08-01), McAnally et al.
patent: 5945746 (1999-08-01), Tracewell et
patent: 5969941 (1999-10-01), Cho
patent: 6018464 (2000-01-01), Kim
patent: 6051780 (2000-04-01), Fuhrmann et al.
patent: 6075698 (2000-06-01), Hogan et al.
patent: 6185097 (2001-02-01), Behl
Ferranti Stephen A.
He Jin
Jorgenson Gregory P.
Bui Hung
Gaffin Jeffrey
Locke Liddell & Sapp LLP
Lucent Technologies - Inc.
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