Retaining device for heat sink

A retaining device (20) for mounting a heat sink (30) to an electronic device (40) includes an unitary metal wire clip (22), a locking device (26) and a camming member (24). The clip includes a pair of spaced apart pressing beams (221), at least one latching beam (223) and a crossbeam (225). The latching beam is set at one side of the pressing beams. The crossbeam extends between the pressing beams at an opposite side thereof. The camming member is pivotably attached to the locking device and includes a cam (242) being engageable with the crossbeam. The camming member is pivotable relative to the locking device from an unlocked position to a locked position and the pressing beams force the heat sink into close contact with the electronic device when the camming member is located at the locked position.

TECHNICAL FIELD

The present invention relates generally to a reining device for heat sink, and more particularly to a retaining device which can conveniently mount a heat sink to an electronic device.

BACKGROUND

It is widely acknowledged that heat is produced during operations of electronic devices such as clipsets or processors of computers. The faster the operation speed is, the larger the amount of heat produced by the electronic device is. However, excessive heat accumulated at the electronic device is likely to affect operations of the electronic device and even results in computer crashes. Therefore, a heat dissipation device such as a heat sink is needed for heat dissipation of the electronic device.

In order to keep the heat sink into close contact with the electronic device, retaining devices such as retainers or fasteners are generally required.FIGS. 7–8illustrate a prior art heat sink retainer20used for attaching a heat sink40to a central processing unit (CPU)50mounted on a socket60. The socket60has a pair of catches601formed at opposite sides thereof, for engaging with the retainer20. The retainer20includes a main body210and a bolt220. The body210has a central pressing portion211for pressing the heat sink40onto the CPU50. First and second latching arms212,213respectively depend from two free ends of the central pressing portion211. Each latching arm212,213defines an opening214,215for receiving a corresponding catch601of the socket60. A V-shaped spring portion216extends outwardly from a central section of the second latching arm213, for adjusting the height of the second latching arm213. In assembly, the openings214,215of the latching arms212,213loosely receive the corresponding catches601of the socket60, and then the blot220is screwed into a hole217defined at the spring portion216to adjust the height of the second latching arm213. As a result, the openings214,215of the latching arms212,213securely receive the catches601of the socket60and the central pressing portion211exerts a downward force on the heat sink40to thereby maintain the heat sink40into close contact with the CPU50. However, this kind of retainer needs a special tool during mounting or dismounting of the heat sink, which is not appreciated by users or operators.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a heat sink retaining device which can conveniently mount a heat sink to an electronic device without using of any tools.

In order to achieve the object set out above, a retaining device for heat sink in accordance with a preferred embodiment of the present invention is used to an electronic device mounted on a printed circuit board. The retaining device comprises an unitary metal wire clip, a locking device and a camming member. The clip includes a pair of spaced apart pressing beams, at least one latching beam and a crossbeam. The latching beam is set at one side of the pressing beams. The crossbeam extends between the pressing beams at an opposite side thereof. The camming member is pivotably attached to the locking device and includes a cam being engageable with the crossbeam. The camming member is capable of moving relative to the locking device between an unlocked position and a locked position. The pressing beams force the heat sink into close contact with the electronic device when the camming member is located at the locked position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1illustrates a heat sink retaining device20according to a preferred embodiment of the present invention, together with a heat sink30, an electronic device such as a central processing unit (CPU)40mounted on a printed circuit board50and a retention module10mounted on the printed circuit board50surrounding the CPU40. The retaining device20functions to mount the heat sink30to the CPU40for heat dissipation.

The retention module10has a configuration of rectangular in shape and a plurality of catches13,14,15formed at opposite sides thereof. The heat sink30includes a base32, a plurality of spaced cooling fins33extending upwardly from the base32and a cooling fan36mounted on a top of the fins33. A plurality of U-shaped heat pipes35connects the base32with an upper portion of the fins33. The base32defines at opposite sides thereof a pair of parallel grooves34with the fins33located there between.

Referring toFIG. 2, the retaining device20includes a clip22, a locking device26, a camming member24being engageable with the clip22as an urging member and a pivot28for connecting the camming member24with the locking device26. The clip22is integrally made from an unitary metal wire and includes a pair of spaced apart pressing beams221, two latching beams223extending from one side of the pressing beams221and a crossbeam225extending between the pressing beams221at an opposite side thereof. Each latching beam223extends from a first end of a corresponding pressing beam221and terminates at a locking portion224corresponding to the first catch13of the retention module10. Each pressing beam221is bent to form a V-shaped pressing portion222at a middle section thereof for providing sufficient resiliency. The crossbeam225includes a semicircular engagement portion227formed at a middle section thereof and two inclined extension arms226each extending between a second end of a corresponding pressing beam221and the engagement portion227.

The locking device26is integrally made from a metal plate and includes two spaced tabs262faced each other. A retaining hole264is defined in the lower portions of the tabs262for retaining the second catch14of the retention module10. A pair of aligned pivot holes (not labeled) is defined in the upper portions of the tabs262for extension of the pivot28therethrough.

The camming member24includes a cam242, a hooked portion244and an operation handle241extending between the cam242and the hooked portion244. A pivot hole248is axially defined through the cam242, corresponding to the pivot holes of the tabs262. A groove245is circumferentially defined around a periphery of the cam242, for engagingly receiving the engagement portion227of the clip22. The cam242has an abutting portion246and a releasing portion247at the groove245. The distance between the pivot hole248and the abutting portion246is greater than the distance between the pivot hole248and the releasing portion247. The operation handle241provides anti-skid ribs243at the top surface thereof for facilitating operations. The hooked portion244extends downwardly from the operation handle241below the anti-skids243. In assembly, the camming member24is attched to the clip22via the engagement portion227received in the groove245. The cam242is sandwiched between the upper portions of the tabs262and the pivot28passes through the pivot holes of the tabs262and the cam242to thereby combine them together (seeFIG. 1).

Another embodiment of the clip of the retaining device is shown inFIG. 3. The clip23includes a pair of spaced apart pressing beams231, a latching beam233being engageable with the first catches13of the retention module10and a crossbeam235. The latching beam233and the crossbeam235integrally extend between the pressing beams221at opposite sides thereof.

Referring also toFIGS. 4–7, in operation, the heat sink30is placed in the retention module10with the base32seated on the CPU40. The pressing beams221of the clip22span across a top of the heat sink30with the pressing portions222thereof received in respective grooves34of the base32. The latching beams223of the clip22and the locking device26are loosely attached to the retention module10via the locking portions224and the retaining hole264engaging with the corresponding first and second catches13,14. At this state, the camming member24is located at an unlocked position (seeFIG. 5). The releasing portion247of the groove245is maintained in contact with the crossbeam225and the hooked potion244of the camming member24is located away from the third catch15of the retention module10. Then, the handle241is operated to cause the camming member24to rotate about the pivot28in a first plane parallel to the fins33of the heat sink30until the hooked portion244is retained at the third catch15of the retention module10. At this state, the abutting portion246of the groove245is maintained in close contact with the crossbeam225and the camming member is located at a locked position (seeFIG. 6). When the camming member24rotates from the unlocked position to the locked position, the cam242presses the crossbeam225downward to accordingly cause the locking device26to move up and each pressing beam221to resiliently deflect in a second plane being perpendicular to said first plane. Thus, the locking portions224of the latching beams223and the retaining hole264of the locking device26are firmly retained at respective first and second catches13,14of the retention module10and the pressing portions222of the pressing beams221exert a downward force on the base32to thereby keep the heat sink30into intimate contact with the CPU40.

In disassembly, the hooked portion244of the camming member24is disengaged from the third catch15of the retention module10and is pulled away from the third catch15to the unlocked position. The crossbeam225and the pressing beams221restore to their original states. Accordingly, the locking portions224and the locking device24are released to loosely engage with the retention module10. After that, the retaining device20can be easily removed away from the heat sink30.