Thin fastener of heat sink

Abstract

The heat sink fastener includes a heat conductive board and a flexible metallic wire. The heat conductive board has a pair of pivot portions. The flexible metallic wire has a pair of flexible arms and a middle portion connecting therebetween. Each flexible arm connects to the pivot portion. The pivot portion side of the heat conductive board is formed with a blocking sheet. The middle portion is provided with a bend for being blocked by the blocking sheet. When the flexible metallic wire is hooked to a ring on a circuit board, it will generate pressure to the heat conductive board resulting from the bent flexible arms and the blocked middle portion.

Claims

1 . A heat sink fastener comprising: a heat conductive board having a pair of pivot portions; a flexible metallic wire having a pair of flexible arms and a middle portion connecting therebetween, and each the flexible arm connecting to one of the pivot portions. 2 . The heat sink fastener of claim 1 , wherein the flexible metallic wire is of a U shape. 3 . The heat sink fastener of claim 1 , wherein each the pivot portion is a hollow cylinder formed by curling an edge of the heat conductive board, and each the flexible arm penetrates through one of the hollow cylinders. 4 . The heat sink fastener of claim 1 , wherein free ends of the pair of flexible arms are separately formed with two hooks, and the middle portion is also formed with a hook. 5 . The heat sink fastener of claim 4 , further comprising three rings mounted on a circuit board for being separately penetrated by the three hooks. 6 . The heat sink fastener of claim 1 , wherein the heat conductive board connects a heat pipe. 7 . The heat sink fastener of claim 6 , wherein an end of the heat pipe is sheathed in the heat conductive board. 8 . The heat sink fastener of claim 1 , wherein each of the pair of pivot portions is a hollow cylinder formed by stamping, and each the flexible arm penetrates through one of the hollow cylinders. 9 . A heat sink fastener comprising: a heat conductive board having a pair of pivot portions; a pair of flexible metallic wires, each having a pair of flexible arms and a middle portion connecting therebetween, and each the middle portion connecting to one of the pair of pivot portions. 10 . The heat sink fastener of claim 9 , wherein each the flexible metallic wire is of a U shape. 11 . The heat sink fastener of claim 9 , wherein each the pivot portion is a pair of hollow cylinders formed by curling an edge of the heat conductive board, and each the flexible arm penetrates through one of the two pairs of hollow cylinders. 12 . The heat sink fastener of claim 11 , wherein a blocking sheet is formed at a gap between each the pair of hollow cylinders, and each the middle portion is formed with a bend for being blocked by the blocking sheet. 13 . The heat sink fastener of claim 9 , wherein free ends of the two pairs of flexible arms are separately formed with four hooks. 14 . The heat sink fastener of claim 13 , further comprising four rings mounted on a circuit board for being separately penetrated by the four hooks. 15 . The heat sink fastener of claim 9 , wherein the heat conductive board connects a heat pipe. 16 . The heat sink fastener of claim 15 , wherein an end of the heat pipe is sheathed in the heat conductive board. 17 . The heat sink fastener of claim 9 , each of the pair of pivot portions is a hollow cylinder formed by stamping, and each the flexible arm penetrates through one of the hollow cylinders.
BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The invention relates to heat sinks, particularly to fasteners of heat sinks. [0003] 2. Related Art [0004] With continuous improvement of semiconductor devices, the requirements to heat sinks also increase. On the other hand, electronic devices also constantly tend to be lighter, thinner, shorter and smaller. Thus heat sinks need not only to further improve to satisfy the requirements of heat dissipation of electronic devices, but also to be lighter and thinner than before. [0005] Taiwan patent No. 1305825 discloses a typical heat sink fastener of the CPU (hereinafter “TW825”). TW 825 uses a heat conductive board attached on the CPU, so the heat conductive plate must exert pressure on the CPU. In TW825, the heat conductive board is fastened by four flexible pins at corners. Each flexible pin is composed of a screw and a spring. The screws must penetrate the heat conductive board and the motherboard so as to fasten the heat conductive board on the motherboard. Thus the screws must possess a specific length. On the other hand, the heat conductive board must be further provided with sleeves for being passed through by the screws. In sum, this kind of structure is relatively complicated and its overall height and weight is hard to be reduced, too. This is very disadvantageous to the thin-and light design of computers. [0006] Taiwan patent No. M276267 discloses another similar heat sink fastener (hereinafter “TW 267”). TW267 differs from TW825 by fixing two extended plates on the heat conductive board. The heat conductive board is fixed on the circuit board by fastening the extended plates on the circuit board. Thus there still are the drawbacks the same as TW825. SUMMARY OF THE INVENTION [0007] An object of the invention is to provide a thin fastener of heat sink, which can efficiently simplify the structure of heat sink fastener and reduce overall height and weight. This will be advantageous to the thin and light design of electronic devices. [0008] To accomplish the above object, the fastener of the invention includes a heat conductive board and a flexible metallic wire. The heat conductive board has a pair of pivot portions. The flexible metallic wire has a pair of flexible arms and a middle portion connecting therebetween. Each flexible arm connects to the pivot portion. [0009] To accomplish the above object, the fastener of the invention includes a heat conductive board and a pair of flexible metallic wires. The heat conductive board has a pair of pivot portions. Each the flexible metallic wire has a pair of flexible arms and a middle portion connecting therebetween. Each flexible arm connects to the pivot portion. [0010] The pivot portion side of the heat conductive board is formed with a blocking sheet. The middle portion is provided with a bend for being blocked by the blocking sheet. When the flexible metallic wire is hooked to a ring on a circuit board, it will generate pressure to the heat conductive board resulting from the bent flexible arms and the blocked middle portion. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 is a perspective view of the first embodiment of the invention; [0012] FIG. 2 is a schematic view of the invention and an electronic component to be mounted; [0013] FIG. 3 is a top view of the first embodiment of the invention; [0014] FIG. 4 is a cross-sectional view of the first embodiment of the invention; [0015] FIG. 5 shows another shape of the heat conductive board; [0016] FIG. 6 shows the second embodiment of the invention; and [0017] FIG. 7 shows the third embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION [0018] Please refer to FIG. 1 , which is a perspective view of the first embodiment of the invention. Roughly, the heat sink fastener of the invention includes a heat conductive board 1 and two flexible metallic 2 a, 2 b. [0019] Two opposite sides of the heat conductive board 1 are separately provided with two pivot portions. In this embodiment, each the pivot portion is a pair of hollow cylinders 11 a, 11 b; 12 a, 12 b. Each pair of hollow cylinders 11 a, 11 b; 12 a, 12 b is arranged in a line and may be formed by curling an edge of the heat conductive board 1 . A blocking sheet 13 a, 13 b is formed between each pair of hollow cylinders 11 a, 11 b; 12 a, 12 b. The blocking sheets 13 a, 13 b are coplanar to the heat conductive board 1 and protrude from the two pairs of hollow cylinders 11 a, 11 b ; 12 a, 12 b. [0020] Each of the two flexible metallic wires 2 a, 2 b is of a U shape. It can be defined into a middle portion 23 a, 23 b and two flexible arms 21 a, 22 a; 21 b, 22 b. The middle portion 23 a or 23 b penetrates a pair of hollow cylinders 11 a , 11 b or 12 a , 12 b to form a pivotal connection. And an exposed portion of the middle portion 23 a or 23 b at the location of the blocking sheet 13 a or 13 b is formed with a bend 231 a , 231 b. Preferably, the bend 231 a or 231 b is of a V shape. Of course, it may also be of any other proper shapes. Each the bend 231 a or 231 b is blocked by the blocking sheet 13 a or 13 b to make the middle portion 23 a or 23 b not able to rotate downwards. Besides, free ends of the flexible arms 21 a, 22 a; 21 b, 22 b are preferably separately formed with hooks 211 a , 221 a ; 211 b , 221 b for being fixed on a circuit board. The top of the heat conductive board 1 may be attached by an evaporation end of a heap pipe 3 . The condensation end of the heat pipe 3 may connect to a fin set 4 . [0021] Please refer to FIG. 2 , which is a schematic view of the invention and an electronic component to be mounted. The heat conductive board 1 is used to be mounted on the electronic component 6 on a circuit board 5 . There are four rings 51 a , 51 b , 51 c , 51 d on the circuit board 5 around the electronic component 6 . These rings 51 a , 51 b , 51 c, 51 d are separately corresponding to the four hooks 211 a, 221 a; 211 b, 221 b. After the heat conductive board 1 is put on the electronic component 6 , the flexible arms 21 a, 22 a; 21 b, 22 b are slightly bent to make the hooks 211 a, 221 a, 211 b, 221 b separately pass through the rings 51 a, 51 b, 51 c, 51 d as shown in FIGS. 3 and 4 . At this time, the bends 231 a, 231 b are blocked by the blocking sheets 13 a, 13 b so as to exert pressure to the heat conductive board 1 . As a result, the heat conductive board 1 clings to the electronic component 6 to form a very great thermal contact. [0022] The heat sink fastener of the invention does not require any screw. The invention only employs elasticity from the deformed flexible metallic wires 2 a, 2 b to generate pressure. Not only can the structure be simplified, but also the weight can be reduced, and even the height also can be shortened. These are advantageous to the thin and light design of electronic devices. [0023] FIG. 5 shows another shape of the heat conductive board. The heat conductive board 1 ′ has relatively larger thickness which can sheathe the heat pipe 3 . This can make a better thermo-conductivity between the heat conductive board 1 ′ and heat pipe 3 because of larger contact area and tighter connection. [0024] FIG. 6 shows the second embodiment of the invention. In this embodiment, the flexible metallic wire 2 c is of a U shape, which can be defined into a middle portion 23 c and two flexible arms 21 c, 22 c. The two flexible arms 21 c, 22 c separately penetrate through two pairs of hollow cylinders 11 a, 11 b; 12 a, 12 b. The middle portion 23 c is exposed out of one side of the heat conductive board 1 . The middle portion 23 c and two free ends of the flexible arms 21 c, 22 c are separately formed with hooks 211 c, 221 c, 231 c for penetrating through rings as shown in the abovementioned embodiment. Similarly, the top of the heat conductive board 1 may be attached by a heat pipe 3 connecting with a fin set 4 . In this embodiment, the flexible metallic wire 2 c has three hooks 211 c, 221 c, 231 c, so there should be three rings disposed on a circuit board (not shown) for being penetrated by the hooks 211 c, 221 c, 231 c. [0025] FIG. 7 shows the third embodiment of the invention. In this embodiment, two pivot portions of the heat conductive board 1 ″ are separately provided with two pairs of hollow cylinders 11 c , 11 d ; 12 c, 12 d. Each pair of hollow cylinders 11 c , 11 d; 12 c, 12 d formed by stamping and is arranged in a line. Two flexible arms 21 c , 22 c of the flexible metallic wire separately penetrate through two pairs of hollow cylinders 11 c , 11 d ; 12 c, 12 d. Similarly, the top of the heat conductive board 1 may be attached by a heat pipe 3 connecting with a fin set 4 . [0026] While the forgoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. As such, the appropriate scope of the invention is to be determined according to the claims.

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Cited By (3)

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    JP-2015038396-AFebruary 26, 2015古河電気工業株式会社, Furukawa Electric Co Ltd:Theヒートシンク
    US-2012222836-A1September 06, 2012Tsung-Hsien HuangHeat sink assembly
    US-9175911-B2November 03, 2015Tsung-Hsien HuangHeat sink assembly