Heat dissipation assembly

[0002] 1. Field of the Invention

[0003] The present invention relates to heat dissipation assemblies, and particularly to heat dissipation assemblies which are conveniently assembled prior to transportation and use.

[0004] 2. Related Art

[0005] Advances in microelectronics technology have resulted in electronic devices which process signals and data at unprecedented high speeds. During operation of many contemporary electronic devices such as central processing units (CPUs), large amounts of heat are produced. The heat must be efficiently removed, to prevent the system from becoming unstable or being damaged. Heat dissipation assemblies are frequently used to dissipate heat from these electronic devices.

[0006] Typically, a clip is used to attach a heat sink to an electronic device. The clip is usually integrally formed from a sheet of plastic or steel material. Examples of such heat sink clips are disclosed in U.S. Pat. No. 6,343,015, and Taiwan Patent Application No. 89216225. However, these clips are relatively wide, which requires more base material and thus increases costs. Furthermore, in use, the clip is conventionally disposed in a center of the heat sink. The clip occupies space that would otherwise be occupied by one or more extra heat dissipation fins or heat dissipation pins. Thus the heat dissipation capability of the heat sink is compromised.

[0007] Wire clips have been devised to overcome the above-described shortcomings. Examples of such heat sink clips are disclosed in Taiwan Patent Applications Nos. 87218992 and 87205513. In each disclosure, the clip forms part of an assembly that includes a heat sink. The clip is a separate part that must be individually packed and transported prior to assembly and use. This is inconvenient, and unduly inflates costs. Furthermore, in assembly, the procedure is unduly complicated, and operating space available for manipulation of the clip is limited. This is particularly inefficient for mass production runs.

[0008] Thus, an improved heat dissipation assembly which overcomes the above-mentioned problems is desired.

[0009] Accordingly, an object of the present invention is to provide a heat dissipation assembly which is conveniently assembled prior to transportation and use.

[0010] Another object of the present invention is to provide a heat dissipation assembly having wire clips which are easily and inexpensively made, and which occupy minimal space on a heat sink of the heat dissipation assembly.

[0011] Still another object of the present invention is to provide a heat dissipation assembly having a pair of wire clips which can securely attach a heat sink to an electronic package.

[0012] To achieve the above-mentioned objects, a heat dissipation assembly of the present invention is for dissipating heat from a central processing unit (CPU) mounted on a printed circuit board (PCB). The heat dissipation assembly comprises a heat sink, two wire clips, a fixing frame, and a fan attached to the fixing frame. Two grooves are transversely defined through fins of the heat sink. Each clip has a central portion received in a corresponding groove, and two arms extending from the central portion. A hook is formed at a distal end of each arm. An offset part is formed at the central portion, for limiting rotation of the clip in the groove. The fixing frame is secured to the heat sink, and comprises a top wall and two side walls depending from the top wall. Two cutouts are defined in a lower portion of each side wall, corresponding to the grooves of the heat sink. Opposite ends of the central portion of each clip protrude out through corresponding cutouts of the fixing frame. The clips are held in the heat sink prior to transportation and use of the heat dissipation assembly.

[0013] Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention together with the attached drawings, in which:

[0014] FIG. 1 is an exploded, isometric view of a heat dissipation assembly in accordance with the present invention, together with a CPU and a surrounding retention module mounted on a PCB;

[0015] FIG. 2 is a partly assembled view of FIG. 1, showing clips of the heat dissipation assembly prior to their attachment to the retention module; and

[0016] FIG. 3 is a fully assembled view of FIG. 1, showing the clips of the heat dissipation assembly attached to the retention module.

[0017] Referring to FIG. 1, a heat dissipation assembly in accordance with the present invention comprises a fan 10, a fixing frame 20, a pair of wire clips 30, a heat sink 40 and a retention module 50. An electronic package 60 such as a central processing unit (CPU) 60 is attached to a printed circuit board (PCB) 70. The retention module 50 is mounted to the PCB 70 by conventional means, and comprises a rectangular chassis surrounding the CPU 60. The retention module 50 further comprises four posts 502 extending upwardly from four corners of the chassis respectively. A locking hole 504 is defined in an upper portion of each post 502.

[0018] The heat sink 40 has a base 401, and a plurality of parallel fins 403 extending upwardly from the base 401. A horizontal supporting plate 408 is formed at one side of the base 401, for supporting the fan 10 thereon. Two parallel grooves 402 are transversely defined through the plurality of fins 403, for accommodating the wire clips 30 therein. Two threaded holes 404 are defined in a lower portion of each of two outmost fins 403 that are at opposite sides of the heat sink 40 respectively. At each outmost fin 403, the threaded holes 404 are generally at respective opposite sides of the grooves 402.

[0019] Each wire clip 30 is integrally made from a single piece of spring steel wire. The wire clip 30 comprises a central portion 302, and two spring arms 304 extending perpendicularly in a same direction from opposite ends of the central portion 302 respectively. A middle part of the central portion 302 is offset from and parallel to remaining parts of the central portion 302. A distance of such offset is greater than a width of either of the grooves 402 of the heat sink 40. A distal end of each spring arm 304 is bent inwardly to form a hook 306.

[0020] The fan 10 is generally parallelepiped, and defines four through apertures 102 in four corners thereof respectively. Four screws 104 are for attaching the fan 10 to the fixing frame 20.

[0021] The fixing frame 20 comprises a top plate 212, and two side plates 202 depending from the opposite sides of the top plate 212 respectively. A vertical slanted flange 207 is bent inwardly from one side edge of each side plate 202. The slanted flanges 207 symmetrically oppose each other across the fixing frame 20. Two fixing tabs 208 extend inwardly from top and bottom ends respectively of each flange 207. Each fixing tab 208 defines a threaded aperture 209 therein, corresponding to a respective one of the through apertures 102 of the fan 10. Two through holes 204 are defined in a bottom portion of each side plate 202, corresponding to two respective threaded holes 404 of the heat sink 40. Two cutouts 206 are defined in the bottom portion of each side plate 202 between the through holes 204, corresponding to the grooves 402 of the heat sink 40. Four screws 205 are for attaching the fixing frame 20 to the heat sink 40.

[0022] Referring also to FIGS. 2 and 3, in assembly, the fan 10 is attached to the fixing frame 20. The screws 104 are extended through the through apertures 102 of the fan 10 and engaged in the threaded apertures 209 of the fixing tabs 208 of the fixing frame 20. Then the central portions 302 of the clips 30 are placed into the grooves 402 of the heat sink 40. The offset part of the central portion 302 of each clip 30 can limit an angle of rotation of the clip 30 in the corresponding groove 402. The spring arms 304 of each clip 30 extend inclinedly upwardly alongside respective outmost fins 403 of the heat sink 40. The combined fixing frame 20 and fan 10 is then placed over the heat sink 40. The fan 10 is supported by the support plate 408 of the heat sink 40. The side plates 202 of the fixing frame 20 abut respective outmost fins 403 of the heat sink 40. Opposite ends of the central portion 302 of each clip 30 protrude out through corresponding cutouts 206 of the fixing frame 20. The spring arms 304 of each clip 30 extend inclinedly upwardly alongside respective side plates 202 of the heat sink 40. The screws 205 are extended through the through holes 204 of the fixing frame 20 and engaged in the threaded holes 404 of the heat sink 40. The fixing frame 20 is thus secured to the heat sink 40 to form the heat dissipation assembly. The clips 30 are held in the heat sink 40 prior to use of the heat dissipation assembly.

[0023] In use, the heat dissipation assembly is placed onto the CPU 60. The base 401 of the heat sink 40 contacts the CPU 60. The spring arms 304 of the clips 30 are depressed so that the hooks 306 of the spring arms 304 are resiliently engaged in the locking holes 504 of the retention module 50. Thus, the heat dissipation assembly is firmly and securely attached to the CPU 60.

[0024] It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present example and embodiment are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.