Patent Application
20070121309
1. Field of the Invention
The present invention relates to a shielding device, and particularly to a shielding device for providing EMI (electromagnetic interference) protection for electronic components on a circuit board.
2. Description of the Prior Art
U.S. Pat. No. 6,711,032 B2 discloses a conventional shielding device comprising a cover and a base frame mounted on a printed circuit board (PCB). A plurality of flanges are bended from outer edges of the cover and define multiple apertures extending therethrough. The base frame comprises side walls with a plurality of outwardly dome shaped projections for engaging with the apertures when the shielding device is in closed position. The projections can firmly engaging with the apertures in a height direction of the shielding device, and wherein the dimension of the apertures in the longitude direction is larger than that of the projections. However, since the projections are formed in the frame by stamping process, the frame is sometimes troublesome to provide excellent flatness when mounted on the PCB, thereby increasing the cost of the manufacture.
Thus there is a need for an improved shielding device which can overcome the disadvantage of the prior art.
It is an object of the present invention to provide a shielding device with excellent flatness and low cost.
To fulfill the above-mentioned objects, according to a preferred embodiment of the present invention, a shielding device comprises a frame and a top cover enclosing the frame. The frame comprises a top wall and a plurality of side walls depending downwardly from the top wall. The side walls comprise a plurality of ellipse shaped mounting holes defined therethrough. The top cover comprises a body portion and a plurality of flanges extending downward from the body portion. The flanges define a plurality of dome shaped projections and a plurality of half ball shaped protrusions all projecting inwardly from the central portions of the flanges. The projections can firmly engaging with the mounting holes in a height direction, and wherein the dimension of mounting holes in a longitude direction is lager than that of the projections, thereby providing a wide possible engaging area. So it doesn't need precisely mating relationship between the projections and the mounting holes and facilitates the assembled process of the shielding device. Besides, the protrusions are intervening with the frame and form a small gap between the frame and top cover, thereby it is easy to disassemble the shielding device. Further more, the projections are disposed on the top cover instead of the frame, thereby providing excellent flatness of the frame and decreasing the cost of the manufacture.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.
The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which:
Reference will now be made in detail to the preferred embodiment of the present invention.
Referring to
The frame 10 comprises a narrow, horizontal top wall 100 and a plurality of side walls 101 depending downwardly from outer edges of the top wall 100 wherein the side walls 101 are separated from each other. The frame 10 further defines a pair of openings 103, 105 and a separated wall 104 between said openings 103, 105. The openings 103, 105 are adapted for enclosing the electronic elements on the circuit board. The side walls 101 comprise a plurality of ellipse shaped mounting holes 102 defined therethrough. The dimension in the longitude direction of the mounting holes 102 is signed as “W”. The dimension in the height direction perpendicular to the longitude direction of the mounting holes 102 is signed as “V” which is shorter than “W” (seen in
The top cover 11 comprises a body portion 110 and a plurality of holes 112 formed therein. A plurality of flanges 111 extends from outer edges of the body portion 110. Some flanges 111 define a number of dome shaped projections 114 projecting inwardly from the central portions of the flanges 111 for detachably engaging with corresponding mounting holes 102 of the frame 10. Other flanges 111 contain a plurality of half ball shaped protrusions 113 extending inwardly from the central portions of the flanges 111 for intervening against the frame 10. As shown in
During assembly, the flanges 111 of the top cover 11 are brought to slide in the height direction over the side walls 101, and the dome shaped projections 114 easily encounter the mounting holes 102. The top cover 11 is firmly assembled to the frame 10 by the engagement of the projections 114 and the mounting holes 102 in the height direction. The protrusions 113 are intervening with the frame 10 thereby forming a small gap between the frame 10 and top cover 11 (seen in
Referring to
It is to be understood, however, that even though numerous, characteristics and advantages of the present invention have been set fourth in the foregoing description, together with details of the structure and function of the invention, the disclosed is illustrative only, and changes may be made in detail, especially in matters of number, shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200520134139.1 | Nov 2005 | CN | national |
