Abstract:
A fastening structure for dissipation device has a metal plate with at least one screw hole, a screw with an engagement part, an elastic element, and a screw cap. The screw and the elastic apparatus are assembled in the screw hole. The screw cap, whose clamp structures are fastened to the outside of the screw hole, limits movement of the screw and the elastic element in the screw hole. The screw is allowed to move upward and downward within a predetermined scope.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The present invention relates to a fastening structure. More particularly, the present invention relates to a fastening structure for a dissipation device.  
           [0003]    2. Description of Related Art  
           [0004]    As the information technology and computer industry advances, portable electronic apparatuses, such as notebook computers, and other precise instruments are widely used. Owing to demands for convenience and practicality, the portable electronic product is designed to be lighter, thinner, shorter, and smaller. For example, a notebook PC is required to be lighter, thinner and powerful in computing performance.  
           [0005]    Because of requirements for lighter, thinner, shorter, and smaller portable electronic apparatuses, many challenges arise in the manufacturing of electronic components and assembly of apparatuses. For example, there are several fastening methods for a dissipation device, such as bolt fastening with a spring and bolt fastening with an elastic plate. In practice, it is suitable to fasten a dissipation device in an ultra-thin notebook PC by bolt fastening with an elastic plate. However, this method occupies a larger area and the contact pressure of the dissipation device is not easily adjusted. If bolt fastening with a spring is employed to fasten a dissipation device in an ultra-thin notebook, it occupies smaller area and the contact pressure of the dissipation device is easily adjusted. Nevertheless, more space (or a higher space) is necessary while assembling the dissipation device by bolt fastening with spring.  
         SUMMARY OF THE INVENTION  
         [0006]    It is therefore an objective of the present invention to provide a fastening structure for a dissipation device so as to overcome the drawback of bolt fastening with spring.  
           [0007]    In accordance with the foregoing and other objectives of the present invention, a fastening structure for a dissipation device includes a metal plate having at least one screw hole, a fastening screw with an engagement part, an elastic element, and a screw cap. The fastening screw, equipped with the elastic element, is assembled in the screw hole. The screw cap, having clamp structures fastened to the outside of the screw hole, limits movement of the screw and the elastic element in the screw hole. The screw is allowed to move upward and downward within a predetermined scope.  
           [0008]    In conclusion, the fastening structure can provide a movable screw cap to provide a dissipation device assembly procedure within a minimum space (height). An elastic element is added to provide contact pressure between the dissipation device and the electronic component. Because of the above improvements, the fastening structure occupies smaller assembly space and has balanced stresses on three screw assembly modules.  
           [0009]    It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,  
         [0011]    [0011]FIG. 1 illustrates a perspective view of a fastening structure for heat dissipation device according to one preferred embodiment of this invention; and  
         [0012]    [0012]FIG. 2 illustrates an exploded view of a fastening structure for heat dissipation device according to one preferred embodiment of this invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.  
         [0014]    The present invention is directed to solving the space limitation issue while a heat dissipation device is fixed by bolt fastening. In one preferred embodiment of present invention, a screw cap is employed to keep a fastening screw and an elastic element in an assembly hole so as to minimize the space for assembly and prevent the fastening screw and the elastic element from slipping out of the assembly hole. The cap can avoid an unbalancing stress between the heat dissipation device and a component during the assembly process.  
         [0015]    [0015]FIG. 1 illustrates a perspective view of a fastening structure for heat dissipation device according to one preferred embodiment of this invention. The preferred embodiment includes a dissipation fin  12 , a heat pipe  14  and a fastening structure  38 . The fastening structure functions to fix a heat dissipation module, including the dissipation fin  12  and the heat pipe  14 , to an electronic component. The heat generated by the component is propagated via the fastening structure  38 , the heat pipe  14  and the dissipation fin  12  sequentially. The dissipation fin  12  is made of a plurality of smaller fins to increase dissipation surface and efficiency. However, the contact status between the heat dissipation module and the electronic component can also influence dissipation efficiency. In other words, fastening pressure is a critical factor for dissipation efficiency.  
         [0016]    Referring FIG. 1 again, fastening screws and elastic elements are employed to fasten the heat dissipation device to an electronic component. The fastening structure  38  includes several screw assembly modules  16 . In this preferred embodiment, 3-point fastening is preferred because 3-point fastening method occupies less area than 4-point fastening method does. Thus, the fastening structure  38  consists of 3 screw assembly modules  16 . Each screw assembly module  16  includes a housing cap  32 , a fastening screw (illustrated in FIG. 2) and an elastic element (illustrated in FIG. 2). The fastening screw is a bolt or a screw. The housing cap  32  is a screw cap. The elastic element is a spring.  
         [0017]    [0017]FIG. 2 illustrates an exploded view of a fastening structure for heat dissipation device according to one preferred embodiment of this invention. The fastening structure  38  includes a metal plate  20 , fastening screws  34 , elastic elements  36 , housing caps  32  and a base plate  42 . The metal plate  20  is made of a material with high thermal conductivity or low thermal resistance.  
         [0018]    Referring to FIG. 2, the metal plate  20  includes several holes  35 , equipped with ribs  18  outside the holes. The holes  35  can be screw holes. One end of the fastening screw  34  is an engagement part  37 . The elastic element  36  can be disposed around the fastening screw  34  and be attached to the engagement part  37 . Both the fastening screw  34  and the elastic element  36  are inserted into the holes  35  of the metal plate  20 . The housing cap  32  is disposed upon the fastening screw  34  and is clamped to the outside of the hole  35 . The housing cap  32  can keep the fastening screw  34  and the elastic element  36  in the hole  35 .  
         [0019]    Referring to FIG. 2 again, the housing cap  32  includes a tab  22 , employed to clamp the rib  18  outside the hole  35 . The rib  18  can slide within the tab  22 . That is, the housing cap  32  can slide upward or downward in relation to the hole  35 . The tab  22  can be a flange with a slot  33  allowing the rib  18  to slide within. The slot  33  can be a square opening. The dimension of the slot  33  can decide sliding range of the housing cap  32 . Thus, the housing cap  32  and the fastening screw  34  can move upward and downward respectively, but the housing cap  32  limits movement of the fastening screw  34 .  
         [0020]    In the screw assembly module  16 , the housing cap  32  covers the fastening screw  34  so as to prevent the fastening screw  34  from slipping out of the hole  35 . Specially, the housing cap  32  leaves a free space for the fastening screw  34  rather than being attached to the fastening screw  34 . However, the housing cap  32  can prevent the fastening screw  34  from slipping out the hole  35 .  
         [0021]    Such housing cap design is directed to assembling the fastening structure smoothly. If the housing cap  32  is attached to the fastening screw  34  and one of three screw assembly modules  16  is assembled prior to the other two, stress will be generated in the other two screw assembly modules  16 . The problem may causes the threads of the fastening screw  34  to be damaged and causes the fastening structure to be stressed in an unbalanced manner. Therefore, the concept “Design for Manufacturing” of the fastening structure is employed to improve assembly procedures and to reduce manufacturing cost.  
         [0022]    In practice, the fastening structure  38  need to be firmly attached to an electronic component  50 , disposed on a printed circuit board  40 . In order to cause the heat, generated by the electronic component  50 , to be effectively transferred to the heat dissipation module, an appropriate pressure is placed on the metal plate  20  of the fastening structure  38 . In one preferred embodiment of present invention, the elastic element  36  is employed to provide a suitable pressure. The elastic element  36  can be a spring or other elastic material.  
         [0023]    During the assembly procedure, the fastening screw  34  equipped around with the elastic element  36  is inserted into the hole  35  of the metal plate  20 . The metal plate  20  is fastened to the print circuit board  40  by screwing the fastening screw  34  into threaded assembly hole  39 . Alternatively, the fastening screw  34  can be screwed into a screw nut  44  so as to secure the metal plate  20  and the print circuit board  40 .  
         [0024]    Additionally, the fastening screw  34  may go through the hole  35  and the assembly hole  39 , and be screwed into the assembly hole  43  of a base plate  42 . The print circuit board  40 , including the electronic component  50 , is fastened between the metal plate  20  and the base plate  42 .  
         [0025]    Furthermore, the elastic element  36  can be disposed around the fastening screw  34  while the fastening screw  34  is screwed into the screw nut  44  via the assembly holes  35 ,  39  and  43 . The print circuit board  40 , including the electronic component  50 , is fastened between the metal plate  20  and the base plate  42 .  
         [0026]    According to the preferred embodiment of present invention, the fastening structure can provide a movable screw cap to aid the dissipation device assembly procedure within a minimum space (height). An elastic element is added to provide contact pressure between the dissipation device and the electronic component. Because of the above improvements, the fastening structure occupies smaller assembly space and stress on the three screw assembly modules is exerted in a balanced manner.  
         [0027]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.