Abstract:
A fastener for fixing heat dissipation devices includes a shaft, a cap and an elastic member. The shaft includes a first end, an opposite second end, and a flange between the first and second ends. The cap is detachably engaged with the second end of the shaft. The elastic member partly encloses the shaft, and is retained between the flange and the cap. A heat dissipation device matching with the fastener is also provided.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to fixing apparatus, and particular to fasteners for fixing heat dissipation devices. Heat dissipation devices using the fasteners are also provided. 
         [0003]    2. Description of Related Art 
         [0004]    During operation of electronic devices such as computer central processing units (CPUs), north bridges and south bridges, for example, a large amount of heat is often produced. The heat must be quickly removed from the electronic devices to prevent them from overheating and being damaged. Many heat dissipation devices are attached to an outer surface of the electronic device to absorb the heat from the CPU, and fasteners usually fix the heat dissipation device. This can be unreliable and inconvenient for installation and removal. 
         [0005]    Therefore, it is necessary to provide a kind of fastener for fixing the heat dissipation device, with satisfied reliability and convenient disassembly process. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. 
           [0007]      FIG. 1  is a schematic view of a heat dissipation device fixed with fasteners in accordance with the present disclosure. 
           [0008]      FIG. 2  is a partially exploded view of the heat dissipation device and the accompanying fasteners of  FIG. 1 . 
           [0009]      FIG. 3  is an exploded view of one of the fasteners of  FIG. 1 . 
           [0010]      FIG. 4  is a schematic assembly view of one of the fasteners of  FIG. 1  fixing the heat dissipation device. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Reference will now be made to the drawings to describe the present fastener, in detail. 
         [0012]    Referring to  FIG. 1  and  FIG. 2 , fasteners  20  according to an exemplary embodiment of present disclosure are provided together with a heat sink  30 , and a supporter  10  supporting the heat sink  30 . 
         [0013]    The supporter  10  includes a main body  11 , and four protrusions  12 . In this embodiment, the main body  11  is a rectangular plate, the four protrusions  12  extend slantwise respectively from four corners of the main body  11 . The supporter  10  has its bottom surface attached to a heat conducting plate  40 , which is used for contacting heat generating components (not illustrated). The supporter  10  has its upper surface attached to the heat sink  30 . The four protrusions  12  each have a strip configuration with a through hole  13  defined at a distal end thereof. 
         [0014]    The heat sink  30  includes a plurality of fins  31  parallel to each other. 
         [0015]    Also referring to  FIG. 3  and  FIG. 4 , each of the fasteners  20  includes a shaft  21 , a screw cap  22  and an elastic member  23  partly enclosing the shaft  21 . 
         [0016]    The shaft  21  includes a first thread end  210 , a second thread end  211  opposite to the first thread end  210 , and a middle portion  212  interconnecting the first thread end  210  and the second thread end  211 . 
         [0017]    The first thread end  210  has a cylindrical configuration with threads formed on an outer sidewall. 
         [0018]    The middle portion  212  has a cylindrical configuration. An annular flange  213  protruding from a peripheral sidewall of the shaft  21 , at a joint of the middle portion  212  and the first thread end  210 . The annular flange  213  has an outer diameter larger than a diameter of the through hole  13 . 
         [0019]    The second thread end  211  has a cylindrical configuration with threads formed on an outer sidewall. In a further embodiment, the second thread end  211  further includes Phillips head  214  at a free end surface. As such, Phillips screwdrivers can turn the shaft  21 . Accordingly, the first thread end  210  of the shaft  21  can be assembled into a threaded hole on circuit boards (not illustrated). 
         [0020]    The screw cap  22  includes an annular engaging portion  221  and a barrel portion  222  surrounding the engaging portion  221 . In this embodiment, the engaging portion  221  and the barrel portion  222  are integrally made from one piece of member. 
         [0021]    The engaging portion  221  includes a through hole  223  defined at a center thereof. The through hole  223  has threads formed on an inner sidewall. As such, the second thread end  211  can be threaded with the engaging portion  221 . 
         [0022]    The barrel portion  222  extends from a peripheral circumference of the engaging portion  221 , along a longitudinal direction of the annular engaging portion  221  and away from the middle portion  212 . An end part of the barrel portion  222  extends beyond the engaging portion  221  to form a sleeve at an end of the engaging portion  221 . The sleeve has an internal diameter equal to an external diameter of the engaging portion  221 . 
         [0023]    The elastic member  23  can be a helical spring. The elastic member  23  has an inner diameter larger than a diameter of the middle portion  212 . The elastic member  23  has an outer diameter smaller than that of the barrel portion  222 . 
         [0024]    When the fastener  20  is fixed to the heat supporter  10 , the second thread end  211  and the middle portion  212  is arranged to upwardly penetrate the through hole  13  of the protrusion  12 . Due to the flange  213  having an outer diameter larger than a diameter of the through hole  13 , the first thread end  210  will be retained at a bottom side of the main body  11 , while the second thread end  211  and the middle portion  212  at a top side of the main body  11 . The elastic member  23  encloses the middle portion  212  at the top side of the main body  11 . A bottom end of the elastic member  23  rests on the top of the protrusion  12 . The engaging portion  221  is engaged with the second thread end  211 , thus, the fastener  20  is retained with the supporter  10 . Due to the elastic member  23  having an outer diameter smaller than that of the barrel portion  222 , a top end of the elastic member  23  is blocked under the bottom of the screw cap  22 . As such, the elastic member  23  is retained between the supporter  10  and the screw cap  22 . 
         [0025]    When the fastener  20  is employed to fix the supporter  10  on a circuit board with heat generating components, the first thread end  210  of the fastener  20  is screwed into the circuit board or a back plate attached to the circuit board, by a screwdriver operating the Phillips head  214  of the fastener  20 . Therefore, the supporter  10  is fixed on the circuit board, with the heat conducting plate  40  contacting heat generating components equipped on the circuit board. 
         [0026]    In the embodiment, the barrel portion  222  encloses the Phillips head  214  of the second thread end  211 , thereby protecting the Phillips head  214  from damage by external force, and preventing a head of the screwdriver from sliding away from the fastener  20  when the screwdriver operates the fastener  20 . The engaging portion  221  can also screws toward or away from the middle portion  212  to adjust a compression length of the elastic member  23  to adjust an elastic force on the supporter  10  toward the circuit board. 
         [0027]    When there is any requirement to detached the heat sink  30 , the screw cap  22  can be twisted off the second thread end  211 , and the supporter  10  with the heat sink  30  arranged thereon can be picked up after removing the elastic member  23  without detaching the fasteners  20  engaged on the circuit board. The disassembly process of the heat sink  30  is convenient. 
         [0028]    It is to be noted that, the first thread end  210  can be configured with other engaging structures rather than threads, as long as it is capable being fixed to a circuit boards. The second thread end  211  can also be configured with other engaging structures rather than threads, as long as capable of detachably being engaged with the screw cap  22 . The main body  11  of the supporter  10  can be configured with other shapes, and the number of the protrusions  12  of the supporter  10  is also not limited to four. 
         [0029]    It is to be understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments without departing from the spirit of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.