Abstract:
The invention discloses a fastening device for fasten a heat sink onto a base board. The fastening device comprises a first fastening member, a second fastening member and a third fastening member. When assembling the fastening device to the base board, the second fastening member has to be pivoted with the third fastening member first. Afterwards, the first fastening member is attached to the base board. Finally, the second and third fastening members, which have been assembled, are engaged with the first fastening member, so as to press the heat sink tightly. Accordingly, the heat sink will be fastened on the base board easily and stably.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a fastening device, and particularly, to a fastening device used for fastening a heat sink onto a base board. 
         [0003]    2. Description of the Prior Art 
         [0004]    With the rapid development of electronic technology in recent years, the developing trend of the electronic devices is toward the direction of miniaturization and high-density. The heat generated by the electronic component (e.g., the CPU in a computer) when it operates is gradually increased. If the heat can not be removed in time, the temperature inside the electronic component will increase which leads the normal operation of the electronic component being seriously affected. Presently, the heat-dissipater and the heat pipe are generally set on the electronic component to help the heat dissipation of the electronic device, and a fan is further set on the heat-dissipater to become a heat-dissipating apparatus. The heat in the heat-dissipater will be rapidly dissipated by the airflow generated by the fan when it operates, so that the heat generated by the electronic device will be also brought out. 
         [0005]    Please refer to  FIG. 1 .  FIG. 1  shows a schematic diagram of a heat-dissipating module  1  in the prior art. The heat-dissipating module  1  comprises a fan  10 , a heat pipe  12 , and a heat sink  14 . When fabricating, a CPU (not shown in  FIG. 1 ) is firstly set on a base board  3  in  FIG. 1 . Then, the heat sink  14  is set on the CPU to conduct the heat generated by the CPU when it operates. It should be noticed that two plank members  16   a  and  16   b  are welded on the two sides of the heat sink  14  respectively. Afterward, the screws  18  are used to fix the plank members  16   a  and  16   b  on the base board  3 . At last, one section of the heat pipe  12  is welded on the heat sink  14 . By doing so, the heat generated by the CPU when it operates can be conducted to the exit of the fan  10  via the heat sink  14  and the heat pipe  12 . And, the heat will be further dissipated rapidly by the airflow generated by the fan  10  when it operates. 
         [0006]    However, in the fabrication process of the heat-dissipating module  1  in the prior art, it is complicated to fix the plank members  16   a  and  16   b  on the base board  3  by the screws  18  respectively by hands. Moreover as shown in  FIG. 1 , the heat sink  14  comprises two plank members  16   a ,  16   b  and four screws  18 , thus, the number of components is large and the cost of the components is increased relatively. 
         [0007]    Therefore, the invention provides a simple fastening device to solve the above-mentioned problems. 
       SUMMARY OF THE INVENTION 
       [0008]    The scope of the invention is to provide a fastening device used for fastening a heat sink onto a base board. The base board has a first surface, a second surface, and at least two holes. In an embodiment according to the invention, the fastening device comprises a first fastening member, a second fastening member, and a third fastening member. 
         [0009]    The first fastening member has at least two first engaging parts. The first fastening member is disposed on the first surface to make each of the first engaging parts embedded into the corresponding hole on the base board and exposed out of the second surface. 
         [0010]    The second fastening member is disposed on the second surface. The second fastening member has a first side, a second side adjacent to the first side, a third side opposite to the second side, and a fourth side opposite to the first side. The first side has a second engaging part engaged with the corresponding first engaging part on the first fastening member. The second side has a first pivoting hole; the third side has a second pivoting hole; and the fourth side has a stopping part. 
         [0011]    The third fastening member is disposed on the second surface. The third fastening member has a fifth side, a sixth side adjacent to the fifth side, a seventh side opposite to the sixth side, and an eighth side opposite to the fifth side. The fifth side has a third engaging part engaged with the corresponding first engaging part. The sixth side has a first pivoting axle pivoted with the first pivoting hole on the second fastening member; the seventh side has a second pivoting axle pivoted with the second pivoting hole on the second fastening member. 
         [0012]    In this embodiment, when the second fastening member engages with the corresponding first engaging part via the second engaging part, and the third fastening member engages with the corresponding first engaging part via the third engaging part, the fourth side of the second fastening member and the eighth side of the third fastening member press the heat sink respectively. And, the stopping part of the second fastening member will limit the rotation of the third fastening member. 
         [0013]    Therefore, when the fastening device of the invention is fabricated, it is only needed to assemble the second fastening member and the third fastening member together firstly, and then to engage the second fastening member and third fastening member with the first fastening member respectively. Compared to the prior art, the invention has the following advantages: (1) convenience of fabrication; (2) no screws used to save the cost of screws; (3) simpler structure and fewer fabricating components. 
         [0014]    The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         [0015]      FIG. 1  shows a schematic diagram of the heat-dissipating module in the prior art. 
           [0016]      FIG. 2  shows a schematic diagram of the heat-dissipating module in an embodiment of the invention. 
           [0017]      FIG. 3  shows a schematic diagram of the heat-dissipating module of  FIG. 2  in another view angle. 
           [0018]      FIG. 4  shows an exploded diagram of the heat-dissipating module. 
           [0019]      FIG. 5  shows an enlarging view of the first fastening member in  FIG. 4 . 
           [0020]      FIG. 6  shows an enlarging view of the second fastening member in  FIG. 4 . 
           [0021]      FIG. 7  shows an enlarging view of the third fastening member in  FIG. 4 . 
           [0022]      FIG. 8  shows a schematic diagram of fabricating the second fastening member and the third fastening member. 
           [0023]      FIG. 9  shows a schematic diagram of fabricating the fastening device on the base board in another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Please refer to  FIG. 2  to  FIG. 4 .  FIG. 2  shows a schematic diagram of the heat-dissipating module  5  in an embodiment of the invention.  FIG. 3  shows a schematic diagram of the heat-dissipating module  5  of  FIG. 2  in another view angle.  FIG. 4  shows an exploded diagram of the heat-dissipating module  5 . The heat-dissipating module  5  is suitable to be set in various electronic devices having heat-dissipating requirements, such as a computer or a projector. In general, the base board  7  shown in  FIG. 2  to  FIG. 4  will be set in the electronic devices, so that various electronic components (e.g., a CPU) can be set on the base board  7 . 
         [0025]    As shown in  FIG. 2  to  FIG. 4 , the heat-dissipating module  5  comprises a fan  50 , a heat pipe  52 , and a heat sink  54 . The fastening device  6  of the invention is used for fastening the heat sink  54  onto the base board  7 . The fastening device  6  comprises a first fastening member  60 , a second fastening member  62 , and a third fastening member  64 . The base board  7  has a first surface  70 , a second surface  72 , and four holes  74 . 
         [0026]    Please refer to  FIG. 5 .  FIG. 5  shows an enlarging view of the first fastening member  60  in  FIG. 4 . The first fastening member  60  comprises four first engaging parts  600   a ,  600   b ,  600   c , and  600   d . The first fastening member  60  is disposed on the first surface  70  of the base board  7  to make each of the first engaging parts  600   a ˜ 600   d  embedded into the corresponding hole  74  on the base board  7  and exposed out of the second surface  72 . 
         [0027]    Please refer to  FIG. 6 .  FIG. 6  shows an enlarging view of the second fastening member  62  in  FIG. 4 . The second fastening member  62  has a first hollow part  621 . A first side S 1 , a second side S 2  adjacent to the first side S 1 , a third side S 3  opposite to the second side S 2 , and a fourth side S 4  opposite to the first side S 1  are respectively defined around the first hollow part  621 . The first side S 1  has two second engaging parts  620   a ,  620   b . The engaging parts  620   a ,  620   b  can engage with the two corresponding first engaging parts  600   a ,  600   b  on the first fastening member  60 . The second side S 2  has a first pivoting hole  622 ; the third side S 3  has a second pivoting hole  624 ; and the fourth side S 4  has a stopping part  626 . When fabricating, the first hollow part  621  is used for the third fastening member  64  to cross to pivot with the second fastening member  62  in a scissors type, and then the heat pipe  52  can contact with the heat sink  54  directly. 
         [0028]    Please refer to  FIG. 7 .  FIG. 7  shows an enlarging view of the third fastening member  64  in  FIG. 4 . The third fastening member  64  has a second hollow part  641 . A fifth side S 5 , a sixth side S 6  adjacent to the fifth side S 5 , a seventh side S 7  opposite to the sixth side S 6 , and a eighth side S 8  opposite to the fifth side S 5  are respectively defined around the second hollow part  641 . The fifth side S 5  has two third engaging parts  640   a ,  640   b . The engaging parts  640   a ,  640   b  can engage with the two corresponding first engaging parts  600   c ,  600   d  on the first fastening member  60 . The sixth side S 6  has a first pivoting axle  642 . The first pivoting axle  642  can pivot with the first pivoting hole  622  on the second fastening member  62 . The seventh side S 7  has a second pivoting axis  644 . The second pivoting axle  644  can pivot with the second pivoting hole  624  on the second fastening member  62 . The second hollow part  641  can make the heat pipe  52  to contact with the heat sink  54  directly. 
         [0029]    Please refer to  FIG. 8 .  FIG. 8  shows a schematic diagram of fabricating the second fastening member  62  and the third fastening member  64 . When fabricating, the second fastening member  62  and the third fastening member  64  should be assembled together firstly. As shown in  FIG. 8 , the third fastening member  64  crosses the first hollow part  621  of the second fastening member  62  to pivot with the second fastening member  62  in a scissors type. 
         [0030]    On the other hand, an electronic component (not shown in the figures) is set on the base board  7 . Then, the heat sink  54  is set on the electronic device to conduct the heat generated by the electronic component when it operates by the heat sink  54 . Afterward, the first fastening member  60  is fabricated on the second surface  72  of the base board  7  as shown in  FIG. 3 . Then, the assembled second fastening member  62  and the third fastening member  64  will engage with the first engaging parts  600   a ,  600   b ,  600   c , and  600   d  of the first fastening member  60  respectively. 
         [0031]    In this embodiment, when the second fastening member  62  engages with the corresponding first engaging parts  600   a  and  600   b  on the first fastening member  60  via the second engaging parts  620   a  and  620   b , and the third fastening member  64  engages with the corresponding first engaging parts  600   c  and  600   d  on the first fastening member  60  via the third engaging parts  640   a  and  640   b . Both the fourth side S 4  of the second fastening member  62  and the eighth side S 8  of the third fastening member  64  will press the heat sink  54 . And, the stopping part  626  of the second fastening member  62  will limit the rotation of the third fastening member  64 . By doing so, the heat sink  54  can be firmly fixed. 
         [0032]    Finally, one end of the heat pipe  52  is welded on the heat sink  54 . By doing so, the heat generated by the electronic component when it operates can be conducted to the exit of the fan  50  via the heat sink  54  and the heat pipe  52 . And, the heat will be further dissipated rapidly by the airflow generated by the fan  50  when it operates. 
         [0033]    Please refer to  FIG. 9 .  FIG. 9  shows a schematic diagram of fabricating the fastening device  6 ′ on the base board  7  in another embodiment of the invention. As shown in  FIG. 9 , the structure of the second fastening member  62 ′ is basically the same with that of the above-mentioned second fastening member  62 . The main difference between them is that the fourth side S 4  of the second fastening member  62 ′ further comprises a first fastening part  628  to lock with the base board  7 . In addition, the structure of the third fastening member  64 ′ is basically the same with that of the above-mentioned third fastening member  64 . The main difference between them is that the eighth side S 8  of the third fastening member  64 ′ further comprises a second fastening part  646  to lock with the base board  7 . 
         [0034]    In practical applications, the screws can be used to fix the first fastening part  628  of the second fastening member  62 ′ and the second fastening part  646  of third fastening member  64 ′ onto the base board  7 , as shown in  FIG. 9 . In another embodiment, a riveting process, a welding process, or other process can be used to fix the first fastening part  628  of the second fastening member  62 ′ and the second fastening part  646  of third fastening member  64 ′ onto the base board  7 . By doing so, the fastening device  6 ′ of the invention can fix the heat sink  6 ′ onto the base board  7  more firmly, so that the heat sink will be not separated from the base board  7  due to the collision. 
         [0035]    Compared to the prior art, when the fastening device of the invention is fabricated, it is only needed to assemble the second fastening member and the third fastening member together firstly and then to engage the second fastening member and third fastening member with the first fastening member respectively. Compared to the prior art, the invention has the following advantages: (1) convenience of fabrication; (2) no screws used to save the cost of screw; (3) simpler structure and fewer fabricating components. 
         [0036]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.