Abstract:
A heat dissipation device comprises a heat sink, a fan, and a fan holder. The heat sink includes a base and a plurality of fins arranged on the base. The fan includes a frame having an engaging flange at each corner thereof. The fan holder configured for attaching the fan to the heat sink includes a main body having two opposite sidewalls extending upwardly from two opposite sides of the main body, a peg extending through the sidewall and movable in a direction perpendicular to the sidewall, and a handle capable of operating the peg. At least one of the engaging flanges of the fan is depressed by the peg towards the main body, thereby securing the fan on the fan holder.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device incorporating a fan for dissipating heat generated by an electronic device. The heat dissipation device has a fan holder for attachment of the fan. 
   2. Description of Related Art 
   It is well known that during operation computer electronic devices such as central processing units (CPU) can generate large amounts of heat. The heat must be quickly removed from the electronic device to prevent it from becoming unstable or being damaged. Typically, a heat sink is attached to an outer surface of the electronic device to absorb heat from the electronic device, and the heat absorbed by the heat sink is then dissipated to ambient air. 
   Generally, in order to improve heat dissipation efficiency of a heat sink, a fan is used to provide forced airflow to the heat sink. Usually, the fan is mounted to the heat sink directly or via a fan holder. Conventionally, the heat sink mainly comprises a heat-conducting base for contacting the heat generating electronic device and a plurality of heat dissipating fins extending from one face of the base. Typically, the fan is secured either on the heat sink or the fan holder by a plurality of screws. The fan defines a plurality of fixing holes corresponding to the screw threads of the heat sink or the fan holder. The pluralities of screws are engagingly received in the fixing holes of the fan and the screw threads of the heat sink or the fan holder, thereby attaching the fan to the heat sink. In this way, the fan can be mounted on the heat sink via a number of screws. However, complexities arise when installing the fan to the heat sink by using multiple screws which require a screwdriver to fix in place, as it may slip and damage nearby electronic components. 
   What is needed, therefore, is a heat dissipation device incorporating a fan holder to easily mount a fan on a heat sink. 
   SUMMARY OF THE INVENTION 
   A heat dissipation device comprises a heat sink, a fan, and a fan holder. The heat sink includes a base and a plurality of fins arranged on the base. The fan includes a frame having an engaging flange at each corner thereof. The fan holder adapted for attaching the fan to the heat sink includes a main body having two opposite sidewalls, a peg extending through the sidewall and movable in a direction perpendicular to the sidewall, and a handle capable of operating the peg. At least one of the engaging flanges of the fan is sandwiched between the peg and the main body so that the fan is secured to the fan holder. By pulling the handle outwardly to move the peg outwardly, the fastening of the fan  30  to the fan holder  20  is released. 
   Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Many aspects of the present apparatus and method 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 present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
       FIG. 1  is an assembled view of a heat dissipation device in accordance with a preferred embodiment of the present invention; 
       FIG. 2  is an exploded, isometric view of  FIG. 1 ; 
       FIG. 3  is an enlarged view of a part of a fan holder shown in circled portion III of  FIG. 2 . 
       FIG. 4  is similar to  FIG. 1 , but viewed from a different aspect; 
       FIG. 5  is an exploded, isometric view of  FIG. 4 ; and 
       FIG. 6  is an enlarged view of a part the fan holder shown in circled portion VI of  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 ,  2 ,  4  and  5  illustrate a heat dissipation device in accordance with a preferred embodiment of the present invention. The heat dissipation device comprises a heat sink  10 , a fan holder  20  located on a top of the heat sink  10 , and a fan  30  mounted on the fan holder  20 . 
   The heat sink  10  is integrally extruded from a heat conductive material, such as aluminium, and comprises a base  11  and a plurality of fins  12 ,  14  perpendicularly extending from the base  11 . The base  11  has a bottom face for contacting a heat-generating electronic component such as a CPU (not shown). Heights of the fins  12  gradually decrease with distance from a middle to two lateral sides of the heat sink  10 . The fins  12  are located between the fins  14 . Each fin  14  is slightly higher than the highest one of the fins  12 , and is bent inwardly and horizontally from a top edge thereof to form a support  140 . Each support  140  defines two fixing holes  142  adjacent to two opposite ends thereof for engaging with screws (not shown) to mount the fan holder  20  thereon. 
   As shown in  FIGS. 2 and 3 , the fan holder  20  comprises a main body  21 , two pegs  22 , two springs  24  respectively surrounding the pegs  22  and a handle  26 . The main body  21  is substantially rectangular and made of a resilient metal such as stainless or plated steel. A circular window  210  is defined at a centre of the main body  21  for allowing airflow generated from the fan  30  to pass through. A first sidewall  211  extends upwardly and perpendicularly from one edge of the main body  21 . A locking structure is arranged on the first sidewall  211  for locking one side of the fan  30 . In the preferred embodiment, the locking structure is embodied as two locking plates  2110  extending inwardly and upwardly from a top edge of the first sidewall  211  and located adjacent to two opposite ends of the first sidewall  211 . A second sidewall  212  with a height similar to that of the first sidewall  211 , extends upwardly and perpendicularly from another edge of the main body  21  opposing the first sidewall  211  and is also provided with a locking structure. In the preferred embodiment, the locking structure comprises the two discrete pegs  22  for locking another side of the fan  30 . 
   Particularly referring to  FIGS. 3 and 6 , a connecting plate  213  extends outwardly and horizontally from a top edge of the second sidewall  212 . A mounting plate  214  extends perpendicularly and upwardly from a distal end of the connecting plate  213 . The mounting plate  214  defines two through holes  2142  adjacent to two opposite ends thereof for receiving the pegs  22 . Each through hole  2142  may have any asymmetrical configuration, and is arciform in this embodiment. The mounting plate  214  has two arched flanges  2144  projecting inwardly from an inner side thereof. Each arched flange  2144  is above the connecting plate  213  and incorporates the connecting plate  213  to define a channel (not labeled) in communication with the corresponding through holes  2142 , for accommodating a corresponding peg  22 . 
   The main body  21  has a pair of parallel inhibiting flanges  215  extending upwardly and perpendicularly from two horizontal edges thereof. The inhibiting flanges  215  and the sidewalls  211 ,  212  co-operatively form an enclosure for accommodating the fan  30 . The main body  21  defines a bore  216  adjacent to each corner thereof corresponding to the fixing hole  142  of the heat sink  10 . Two slim tabs  217  tilt upwards from two adjacent corners of the main body  21  approximating to the second sidewall  212  and respectively orient the two adjacent corners of the main body  21 . The tabs  217  upwardly support the fan  30  thereon and incorporate the locking structure of the second sidewall  212  to sandwich the fan  30  therebetween. 
   The handle  26  comprises a semicircular operating portion  262  and two locking portions  264 . The operating portion  262  is positioned at a middle of the handle  26 . The locking portions  264  extend from two opposite ends of the handle  26  and are offset (i.e., extended) toward the mounting plate  214 . Each locking portion  264  defines a locking hole  2640  therein for engagingly receiving an end of a corresponding peg  22 . 
   Each peg  22  is formed from a molded elastic plastic and comprises a head  222  and a shaft  224 . A portion of top surface of the head  222  is cut away to define a slope  2220  upwardly oriented for facilitating the fan  30  to slip thereover. The shaft  224  axially extends from a bottom of the head  222  and has a diameter smaller than that of the head  222 . The shaft  224  defines an annular recess  2242  therein adjoining to a distal end thereof, for fittingly engaging with the locking hole  2640  of the handle  26 . The distal end of the shaft  224  forms a prong with an annular inclined surface at periphery thereof for facilitating the shaft  224  to pass through the locking hole  2640  of the handle  26 . The shaft  224  is dimensioned corresponding to the through hole  2142  and has a flat side face  2241  for fitting with a flat side (not labeled) of the through hole  2142 , so as to avoid rotation of the peg  22  in the through hole  2142 . 
   In the fan holder  20 , the pegs  22  encircled by the springs  24  are extended through the channels, the through holes  2142  and nested in the handle  26  with the locking portions  264  defining the locking holes  2640  securely engaging in the annular recesses  2242  of the pegs  22 . The pegs  22  are movable in the channels and the through holes  2142 . The springs  24  are held between the heads  222  and the mounting plate  214 . The handle  26  is located outside the enclosure of the fan holder  20 . Generally, the pegs  22  are horizontally stretched beyond the connecting plate  213  and extended into the enclosure. However, when the handle  26  is pulled outwardly, the pegs  22  can move through the connecting plate  213  toward the mounting plate  214  and away from the enclosure. 
   The fan  30  has a rectangular frame (not labeled) fittingly accommodated in the enclosure formed by the sidewalls  211 ,  212  and the inhibiting flanges  215 . The frame defines an engaging flange  32  at each corner thereof, which has a height identical to that of the sidewalls  211 ,  212 . 
   Referring to  FIGS. 1-6 , the fan  30  is attached to the heat sink  10  by placing the fan holder  20  on the supports  140  of the heat sink  10  and securing it in place using screws (not shown) extending through the corresponding bores  216  of the fan holder  20  and the fixing holes  142  of the support  140 . Subsequently, the fan  30  is placed slantwise on the fan holder  20 . One side of the fan  30  slides toward the first sidewall  211  until the neighboring engaging flanges  32  at the side of the fan  30  are disposed between the main body  21  and the locking plates  2110 . Another side of the fan  30  is then pushed downwardly. The slopes  2220  of the pegs  22  are forced outwards by the fan  30  and move outwardly towards the mounting plate  214 . The heads  222  of the pegs  22  compress the springs  24  encircling the pegs  22 . After the another side of the fan  30  wholly slides over the slopes  2220 , the pegs  22  are released and leave the mounting plate  214  due to expansion of the springs  24  to urge another two neighboring engaging flanges  32  toward the main body  21  of the fan holder  20 . At this time, the tabs  217  resiliently resist the another two neighboring engaging flanges  32 . Thus, the another side of the fan  30  is fittingly sandwiched between the tabs  217  and the pegs  22 . The fan  30  is therefore firmly secured on the fan holder  20 . 
   The fan  30  is detached from the fan holder  20  by pulling the operating portion  262  of the handle  26  outwardly thus causing pegs  22  to move toward the mounting plate  214 , until the another side of the fan  30  moves out of the enclosure. Then, the fan  30  can easily be removed from the enclosure. 
   Alternatively, the locking structure on the second sidewall  212  can substitute the locking structure on the first sidewall  211 . That is, the first sidewall  211  can be a mirror image of the second sidewall  212  or have a similar structure to the second sidewall  212 . 
   It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereto described merely being preferred or exemplary embodiments of the invention.