Clip for heat sink

[00002] 1. Field of the Invention

[00003] The present invention relates to heat sink clips, and particularly to a clip which readily and securely attaches a heat sink to an electronic device mounted on a circuit board.

[00004] 2. Prior Art

[00005] Computer electronic devices such as central processing units (CPUs) frequently generate large amounts of heat. Many modern high frequency and high speed CPUs become particularly hot during operation, which can destabilize operation and cause damage. A heat sink placed in thermal contact with an electronic device mounted on a socket transfers heat from the electronic device through conduction. Oftentimes, the heat sink is secured to the electronic device by a clip.

[00006] Referring to FIG. 6, a conventional clip assembly comprises a pin 1 and a plug 2. The pin 1 includes a columnar body 3 having a screw thread, and a bifurcated barb 6 formed at a bottom end of the body 3. An aperture 4 is defined through an upper portion of the body 3, and a vertical slot 5 is defined through a lower portion of the body 3 in communication with the aperture 4. The plug 2 includes a shaft 7 corresponding to the aperture 4 of the pin 1, an expanded head 8 formed at a top end of the shaft 7, and a cone-shape insertion end 9 formed at a bottom end of the shaft 7. The insertion end 9 has a diameter substantially greater than that of the shaft 7.

[00007] In assembly, the pin 1 is successively extended through a corresponding aperture 12 of a heat sink 10 and a corresponding fixing hole 22 of a circuit board 20. The plug 2 is then plugged into the pin 1, with the insertion end 9 of the plug 2 pushing along through the vertical slot 5 of the pin 1. The insertion end 9 of the plug 2 then clasps the barb 6 of the pin 1, thereby fixing the heat sink 10 to both the circuit board 20 and an electronic device 24 mounted on the circuit board 20.

[00008] The conventional clip assembly is generally made of insulative material and not attached to a grounding circuit of the circuit board 20. Therefore, the clip assembly does not provide electromagnetic interference (EMI) shielding for the electronic device 24. This can compromise the soundness and stability of the electronic device 24. On the other hand, U.S. Pat. No. 6,112,378 discloses some approach. Anyhow, an easy and economic design is still desired.

[00009] Accordingly, an object of the present invention is to provide a clip which readily and securely attaches a heat sink to an electronic device.

[00010] Another object of the present invention is to provide a clip which provides EMI shielding for an electronic device.

[00011] To achieve the above-mentioned object, a clip in accordance with the present invention comprises a pin and a pressing member, each of which are integrally formed by stamping sheet metal. The pin includes a cylindrical body having a vertical notch defined therein, a pair of symmetrically opposite latches depending from the cylindrical body to enable the pin to elastically deform, and a pair of barbs extending outwardly and slightly upwardly from bottom ends of the latches respectively. The pressing member includes a circular body, a column depending from a middle of the circular body, and a pair of spring arms extending outwardly and downwardly from opposite sides of the circular body. A distal end of each spring arm is bent inwardly and upwardly to form an elbow portion. An opening is defined through the circular body and the column, for receiving the pin.

[00012] Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiment of the present invention with attached drawings, in which:

[00019] Referring to FIG. 1, a pair of clips 30 each in accordance with the present invention can be used for attaching a heat sink 40 to an electronic device 52 mounted on a socket 56 on a printed circuit board (PCB) 50. The heat sink 40 comprises a chassis 42, and a pair of fastening ears 44 respectively extending outwardly in opposite directions from diagonally opposite corners of the chassis 42. Each fastening ear 44 defines a fastening hole 46 therein. A pair of fixing holes 54 is defined in the PCB 50 at diagonally opposite sides of the electronic device 52. The clips 30 are extended through the fastening holes 46 and the fixing holes 54.

[00020] Referring to FIGS. 2 and 3, each clip 30 comprises a pin 32 and a pressing member 34, each of which are integrally formed by stamping sheet metal. The pin 32 includes a cylindrical body having a vertical notch/seam 321 defined therein, a pair of symmetrically opposite latches 323 depending from the cylindrical body to enable the pin 32 to elastically deform, and a pair of stops 325 extending outwardly and slightly upwardly from bottom ends of the latches 323 respectively. In the preferred embodiment, each stop 325 is a barb 325. The pressing member 34 includes a circular body 341, a column 347 depending from a middle of the circular body 341, and a pair of spring arms 343 extending outwardly and downwardly from opposite sides of the circular body 341 respectively. A distal end of each spring arm 343 is bent inwardly and upwardly to form an elbow portion 345. An opening 349 is defined through the circular body 341 and the column 347, for receiving the pin 32.

[00021] Referring also to FIGS. 4 and 5, in assembly, each pin 32 is fixed to the corresponding pressing member 34 with a rivet to form one clip 30. Each clip 30 is pressed through the corresponding fastening hole 46 of the heat sink 40 and corresponding fixing hole 54 of the PCB 50. The barbs 325 of the clips 30 interferentially engage a bottom surface of the PCB 50 at the fixing holes 54, to prevent the clips 30 from separating from the PCB 50. The spring arms 343 of the clips 30 are elastically deformed, thereby causing the elbow portions 345 thereof to resiliently press the fastening ears 44 of the heat sink 40. The heat sink 40 is thus resiliently and firmly attached to the electronic device 52 and the PCB 50.

[00022] The clip 30 of the present invention is formed by stamping sheet metal. Each clip 30 may be attached to a grounding circuit of the PCB 50. Accordingly, the clips 30 are able to provide EMI shielding for the electronic device 52.

[00023] It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present example and embodiment is to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.