Heat sink assembly

A heat sink has a base (10), a plurality of fins (12, 14) and a central receiving groove (16) in the fins. A first positioning portion (1250) extends from a first fin at a side of the receiving groove and a positioning slot (1256) is defined therein. The clip includes a main body (23) and a pair of legs (25). The main body includes a retaining portion (230) and a first pressing portion (232). The main body is received in the receiving groove and the first pressing portion is accommodated in the positioning slot. The retaining portion is offset from the first pressing portion. The legs can be pressed to securely connect with a printed circuit board (3), whereby the heat sink can have an intimate contact with a CPU (4).

FIELD OF THE INVENTION

The present invention relates to heat sink assemblies having clips which readily attach a heat sink to a heat-generating electronic device in a computer.

DESCRIPTION OF RELATED ART

In a computer, a heat sink is often used to remove heat generated by certain electronic devices such as central processing units (CPUs). A clip is frequently used to attach the heat sink to the electronic device. Conventional clips frequently cause difficulties during assembly. This is particularly so when a clip is made of stiff metal with a view to tightly securing a heat sink. A tool is thus often required to effect attachment of the clip. The tool is prone to slip and damage the electronic device and components on and around the electronic device. Furthermore, a conventional clip is passive. Therefore if the heat sink is slightly displaced, the clip cannot self-correct to urge the heat sink to return to its original pre-displaced position. Moreover, when a heat sink is subjected to vibration during normal operation or transportation, certain conventional clips are prone to slip relative to the heat sink. This can seriously reduce the stability of a heat sink assembly and the efficiency of heat removal.

Therefore, an improved heat sink assembly is desired to overcome the above-mentioned problems.

SUMMARY OF THE INVENTION

A heat sink assembly includes a heat sink and a clip. The heat sink has a base and a plurality of fins extending from the base. A central receiving groove is defined between the fins. A first positioning portion extends from a first fin at a side of the receiving groove and a positioning slot is defined therein. The clip includes a main body and a pair of legs extending from opposite ends of the main body. Each leg is provided with a hooked foot at a free end thereof. The main body includes a retaining portion and a first pressing portion extending from the retaining portion. The main body is received in the receiving groove and the first pressing portion accommodated in the positioning slot is positioned between the first positioning portion and the base of the heat sink. The leg can be pressed to a position so that the hooked foot hooks with a handle on a printed circuit board on which an electronic component is mounted. Thus, the heat sink can have an intimate contact with the electronic component.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a heat sink assembly in accordance with a preferred embodiment of the present invention. The heat sink assembly includes a heat sink1and a wire clip2positioned in the heat sink1. The heat sink1has a base10, and first and second arrays of parallel fins12,14extending upwardly from the base10. A central longitudinal receiving groove16is defined between the first and second arrays of fins12,14and extended from one side of the base10to an opposite side of the base10, for receiving the clip2.

Referring toFIGS. 2-3, the first array of fins12comprises a plurality of parallel spaced first fins121and a plurality of channels (not labeled) each extending between two adjacent first fins121. Each first fin121comprises four hooked portions123at four corners thereof, for engaging with each other. An outmost first fin121afacing the receiving groove16has a first positioning piece125and a first flange1218both extending from a bottom edge thereof toward the receiving groove16. The first positioning piece125comprises a first positioning portion1250and a pair of first joining portions1252,1254extending from opposite sides of the first positioning portion1250. The first joining portions1252,1254are attached on a top surface of the base10. The first positioning portion1250is upwardly vaulted and thus defines a first positioning slot1256with a downward opening, for cooperating with the top surface of the base10to position the clip2on the base10of the heat sink1. The first flange1218is attached on the top surface of the base10. The second array of fins14comprises a plurality of parallel spaced second fins141and a plurality of channels (not labeled) each extending between two adjacent second fins141. Each second fin141comprises four hooked portions143at four corners thereof, for engaging with each other. An outmost second fin141afacing the receiving groove16has a second positioning piece145and a second flange1418both extending from a bottom edge thereof and facing the outmost first fin121aof the first array of fins12. The second positioning piece145comprises a second positioning portion1450and a pair of second joining portions1452,1454extending from opposite sides of the second positioning portion1450. The second positioning portion1450is vaulted and thereby defines a second positioning slot1456with a downward opening, for cooperating with the top surface of the base10to position the clip2on the base10of the heat sink1. The second flange1418and the second joining portions1452,1454are attached on the top surface of the base10. The first positioning piece125is arranged in a front end of the first fin group12, while the second positioning piece145is arranged in a rear end of the second fin group14. The first and second flanges1218,1418are located between and separate from the first and second positioning pieces125,145.

The clip2is made from a single piece of metallic wire. The clip2comprises a central main body23, and a pair of legs25extending from opposite ends of the main body23. The main body23comprises three integrally connected portions which are named according to their functions as a retaining portion230in a middle thereof and a pair of pressing portions232extending from opposite ends of the retaining portion230. The retaining portion230is U-shaped and offset away from each pressing portion232. The retaining portion230is upwardly projected from and angled to each pressing portion232, for providing stabilization of the whole clip2and preventing the clip2from moving in a direction parallel to the receiving groove16. Each leg25extends upwardly and outwardly from a distal end of a corresponding pressing portion232. The legs25extend in different directions, and are oriented relative to each other such that the clip30is broadly Z-shaped when viewed from above (see alsoFIG. 2). A hooked foot250extends downwardly and outwardly from a distal end of each leg25.

Referring toFIG. 4, the main body23of the clip2is put on the top surface of the base10of the heat sink1. A bottom of the first array of fins12is attached on one side of the base10and the first positioning portion1250of the first positioning piece125is pressed on a corresponding pressing portion232of the main body23of the clip2so that the pressing portion232of the clip2is received in the first positioning slot1256. The first joining portions1252,1254of the first positioning piece125are mounted on the top surface of the base10so that the pressing portion232is positioned between the first positioning portion1250and the top surface of the base10by the first positioning piece125cooperating with the top surface of the base10. The second array of fins14is placed to attach on an opposite side of the base10and the second positioning piece145is pressed on the other pressing portion232of the clip2so that the other pressing portion232is accommodated in the second positioning slot1456. The second joining portions1452,1454of the second positioning piece145are mounted on the top surface of the base10and the other pressing portion232accommodated in the second positioning slot1456of the second positioning piece145is positioned between the second positioning portion1450and the top surface of the base10by the second positioning piece145cooperating with the top surface of the base10. Thus, the clip2is prevented from moving in vertical and lateral directions. The retaining portion230is projected from the base10of the heat sink1to a level above the first and second positioning portions1250,1450to prevent the clip2from moving in a direction parallel to the receiving groove16of the heat sink1. The first and second positioning portions1250,1450of the first and second positioning pieces125,145cooperate with the top surface of the base10to position the pressing portions232of the clip2on the base10of the heat sink1. After the first array of fins12, the second array of fins14and the clip2are placed on the top surface of the base10of the heat sink1in a manner as shown inFIG. 1, the first array of fins12, the second array of fins14and the base10of the heat sink1are soldered together whereby they are mechanically and thermally connected, while the clip2can be rotated in the first and second positioning slots1256,1456.

FIGS. 5-6show an electronic assembly comprising a printed circuit board (PCB)3and an electronic component such as a CPU4mounted on the PCB3. A pair of locking handles30extend from the PCB3in the vicinity of diagonally opposite corners of the PCB3. The base10of the heat sink1of the heat sink assembly is attached on the CPU4. The legs25of the clip2are pressed downwardly to urge the hooked feet250to hook the locking handles30. The pressing portions232of the clip2abut against the base10of the heat sink1to attach a top surface of the CPU4. Thus, the base10of the heat sink1is firmly pressed against the CPU4by the pressing portions232of the clip2. The heat sink1is securely fastened to the PCB3by the clip2.