Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-07-23
2001-09-18
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S816000, C361S818000, C174S034000, C174S051000
Reexamination Certificate
active
06292373
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the field of electromagnetic interference (EMI) shields and, in particular, to an EMI shield for a disk drive.
BACKGROUND OF THE INVENTION
Electronic chassis that house electronic components for high-speed telecommunications and networking applications typically include a plurality of circuit board assemblies. Each circuit board assembly includes a circuit board that is attached to a channel-shaped mounting bracket.
In certain applications, a disk drive (such as, for example, a floppy disk drive or a CD ROM disk drive) is mounted onto the circuit board of a circuit board assembly. The disk drive is positioned on the circuit board so that its receiving end is aligned with an opening formed in the mounting bracket. This arrangement allows an operator to access the receiving end of the disk drive to allow the insertion and ejection of a disk. However, there are several disadvantages to this arrangement.
In particular, in many instances gaps are created between the disk drive and the opening in the mounting bracket due to parts which are out of tolerance. As a result, excessive amounts of electromagnetic radiation generated by the internal electronic components within the electronic chassis may leak out of the chassis through the gaps formed between the disk drive and the mounting bracket. Excessive electromagnetic interference (EMI) is a widespread problem in many electronic chassis applications, especially in the high-speed network systems products. These electronic chassis must meet very stringent regulatory emissions standards in the United States and in other foreign countries.
Attempts have been made to provide shielding devices to reduce EMI emissions that exit through gaps between the disk drive and the mounting bracket. For example, Beryllium copper gaskets and metallic coated fiber gaskets have been used in an attempt to reduce EMI emissions. However, there are many disadvantages with these solutions, including the high costs associated with these materials. In addition, these conventional gasket designs are typically difficult to fabricate which results in increased manufacturing costs. Moreover, these gaskets typically do not provide a consistent positive and continuous contact between the disk drive and the mounting bracket. As a result, conventional solutions typically do not provide effective EMI shielding.
Accordingly, it would be desirable to have an EMI shield that overcomes the disadvantages described above, and to provide a simple and cost effective EMI shield for a disk drive.
SUMMARY OF THE INVENTION
One aspect of the invention provides an electromagnetic interference (EMI) shield for a disk drive including a body portion for operatively securing to the disk drive. The body portion includes a flange portion having a plurality of tab portions. The plurality of tab portions substantially surrounds a perimeter portion of the body portion to allow a force applied to the body portion to deflect the plurality of tab portions and bias the plurality of tab portions against a contact surface to form a positive contact between the plurality of tab portions and the contact surface thereby shielding EMI. The plurality of tab portions may preferably be angled with respect to the contact surface to allow the plurality of tab portions to deflect when the force is applied to the body portion to form the positive contact between the plurality of tab portions and the contact surface. Each of the plurality of tab portions may preferably be angled at least about three degrees from the contact surface. The body portion may preferably have a rectangular-shape including a top wall, a bottom wall, a first side wall and a second side wall. The body portion may preferably be formed from a single piece of conductive material such as, for example, tin-plated cold rolled steel. The first and second side walls may each preferably include an opening to allow the body portion to be operatively secured to the disk drive. The opening may preferably be a slot.
Another aspect of the invention provides an electromagnetic interference (EMI) shield for a disk drive. A circuit board is operatively secured to a bracket and a disk drive is operatively secured to the circuit board. A body portion is operatively secured to the disk drive. The body portion includes a flange portion having a plurality of tab portions. The plurality of tab portions substantially surrounds a perimeter portion of the body portion to allow a force applied to the body portion in a direction toward the bracket to deflect the plurality of tab portions and bias the plurality of tab portions against a contact surface of the bracket to form a positive contact between the plurality of tab portions and the contact surface. Electromagnetic radiation is thereby prevented from exiting through an opening in the bracket. Each of the plurality of tab portions may preferably be angled with respect to the contact surface of the bracket to allow the plurality of tab portions to deflect when the force is applied to the body portion to form the positive contact between the plurality of tab portions and the contact surface of the bracket. Each of the plurality of flange portions may preferably be angled at least about three degrees from the contact surface of the bracket. The body portion may preferably have a rectangular-shape including a top wall, a bottom wall, a first side wall, and a second end wall.
Another aspect of the invention provides a method of shielding electromagnetic interference (EMI) for a disk drive. A circuit board and a disk drive operatively secured to the circuit board are provided. A body portion is operatively secured to the disk drive. The body portion includes a flange portion having a plurality of tab portions. The plurality of tab portions substantially surrounds a perimeter portion of the body portion. A force is applied to the body portion and the plurality of tab portions is deflected. The plurality of tab portions is biased against a contact surface of a bracket. A positive contact is formed between the plurality of tab portions and the contact surface of the bracket. Electromagnetic radiation is prevented from exiting through an opening in the bracket. The force may preferably be applied to the body portion in a direction toward the bracket. The circuit board may preferably be operatively secured to the bracket.
Another aspect of the invention provides an electromagnetic interference (EMI) shield for a disk drive including a body portion for operatively securing to the disk drive. The body portion includes a flange portion having a plurality of tab portions. The plurality of tab portions is positioned along a longitudinal side of the body portion to allow a force applied to the body portion to deflect the plurality of tab portions and bias the plurality of tab portions against a contact surface to form a positive contact between the plurality of tab portions and the contact surface thereby shielding EMI. The plurality of tab portions may preferably be angled with respect to the contact surface to allow the plurality of tab portions to deflect when the force is applied to the body portion to form the positive contact between the plurality of tab portions and the contact surface. Each of the plurality of tab portions may preferably be angled at least about three degrees from the contact surface. The body portion may preferably have a generally planar-shape including a first side wall and a second side wall. Each of the first and second side walls may preferably include an opening to allow the body portion to be operatively secured to the disk drive. The opening may preferably be a slot. The body portion may preferably be formed from a single piece of conductive material such as, for example, tin-plated cold rolled steel.
The invention provides the foregoing and other features, and the advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accomp
Koradia Amir
Li Hong
Pogatetz Douglas J.
3Com Corporation
Baniak Pine & Gannon
Bui Hung
Gaffin Jeffrey
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