Abstract:
A fan holder adapted for fixing a fan onto a heat sink includes a frame, a fastener pivotedly connected with the frame, and a first resilient member disposed between the frame and the fastener. When the fastener is located at a first position, the first resilient member exerts a resilient force on and keeps the fastener at the first position, and the fan is sandwiched between the fastener and the frame. When an external force is applied on the fastener, the fastener rotates from the first position to a second position in which the fan can no longer be sandwiched between the fastener and the frame, and when the external force is removed, the first resilient member drives the fastener from the second position back to the first position.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure relates to a fan holder capable of conveniently fixing a fan on or detaching the fan from a heat sink, and a heat dissipation device using the fan holder. 
         [0003]    2. Description of Related Art 
         [0004]    Nowadays, numerous kinds of heat dissipation devices are used to dissipate heat generated by electronic devices. Generally, a heat dissipation device includes a heat sink and a fan. The fan is fastened on the heat sink via a plurality of screws serving as fasteners. Typically, a tool such as a screwdriver is required for this. It is very inconvenient and time-consuming to mount the fan on the heat sink through the screws. Furthermore, the fan occasionally needs to be disassembled from the heat sink for maintenance or replacing with another new fan after the fan has been in service for a long time. In disassembly, since the fan is fastened to the heat sink via the screws, a tool (i.e., a screwdriver) is required to detach the screws from the heat sink. Thus, it is inconvenient to disassemble the fan from the heat sink. 
         [0005]    What is needed, therefore, is a fan holder and a heat dissipation device using the fan holder which can overcome the limitations described. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the present embodiments 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 embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIGS. 1-2  are isometric, assembled views of a heat dissipation device in accordance with one embodiment of the disclosure, seen from different viewpoints. 
           [0008]      FIGS. 3-4  are partial and more fully exploded views of the heat dissipation device of  FIG. 1 , respectively. 
           [0009]      FIG. 5  is an enlarged view of a portion V of the heat dissipation device of  FIG. 2 , showing some parts cut away. 
           [0010]      FIG. 6  is an enlarged view of parts of a fan holder of the heat dissipation device shown in  FIG. 4 , such parts including a fastener. 
           [0011]      FIG. 7  is an inverted, enlarged view of the fastener of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIGS. 1-2 , a heat dissipation device in accordance with an embodiment of the disclosure is provided for cooling an electronic device (not shown) mounted on a printed circuit board (not shown). The heat dissipation device comprises a heat sink  10 , a fan  20  placed above the heat sink  10 , a fan holder  30  fixing the fan  20  on the heat sink  10 , and a clip  40  extending across the heat sink  10  for mounting the heat dissipation device on the printed circuit board. 
         [0013]    The heat sink  10  is integrally made of metal such as aluminum, copper or an alloy thereof. The heat sink  10  includes a heat conducting plate  12 , and a plurality of fins  14  upwardly extending from a top face of the heat conducting plate  12 . The fins  14  are parallel with each other and arranged on the top face of the heat conducting plate  12  in a matrix. Top ends of the fins  14  at two opposite sides of the heat sink  10  define two longitudinal locking grooves  140  therein, respectively. 
         [0014]    Also referring to  FIG. 3 , the fan  20  is generally rectangular in shape, and includes an upper flange  22  and a lower flange  24  parallel to the upper flange  22 . Each of the upper and lower flanges  22 ,  24  defines four through holes  26  in four corners thereof. 
         [0015]    Also referring to  FIG. 4 , the fan holder  30  includes a substantially rectangular frame  32 , two fasteners  36  connecting respectively to two diagonal corners of the frame  32 , two first resilient members  34  each disposed between the frame  32  and a corresponding fastener  36 , and four second resilient members  33  disposed in four corners of the frame  32 . In this embodiment, the first resilient members  34  are elastic bent plates, and the second resilient members  33  are coil springs. Considered another way, the first resilient members  34  are keyhole-shaped compression springs. 
         [0016]    Also referring to  FIG. 6 , the frame  32  is integrally made of material such as plastic, and includes a supporting plate  322  and a side wall  324  extending vertically and upwardly from an outer periphery of the supporting plate  322 . The supporting plate  322  and the side wall  324  together form a receiving space  323  in the frame  32  for receiving the lower flange  24  of the fan  20  therein. The supporting plate  322  defines a circular through hole  3220  in a center thereof for allowing airflow generated from the fan  20  to pass therethrough. Four circular locating grooves  325  are defined in the four top corners of the supporting plate  322 . A locating post  327  protrudes upwardly from a center of each locating groove  325 , corresponding to a respective through hole  26  of the lower flange  24  of the fan  20 . Two spaced, elastic clasps  328  extend vertically downwardly from each of two opposite sides of a bottom of the supporting plate  322 , corresponding to the locking grooves  140  of the heat sink  10 . Each clasp  328  includes an elastic arm  3282 , and a hook  3284  extending inwardly from a distal end of the arm  3282 . Two mounting portions  326  extend horizontally and outwardly from the two diagonal corners of the frame  32 . Each mounting portion  326  defines a mounting groove  3260  therein. The mounting groove  3260  includes a first circular portion  3263 , and a second truncated sector-shaped portion  3264  communicating with the circular portion  3263 . A through hole  3262  is defined through the mounting portion  326  at a center of the circular portion  3263 . 
         [0017]    Each coil spring  33  is received in a corresponding locating groove  325  of the frame  32 , and surrounds the locating post  327  in the locating groove  325 . The coil spring  33  is tapered. A diameter of a bottom end of the coil spring  33  is slightly larger than an inner diameter of the locating groove  325  of the frame  32 , so that the bottom end of the coil spring  33  can interferentially fit in the locating groove  325  of the frame  32 . A diameter of a top end of the coil spring  33  is larger than that of the corresponding through hole  26  of the lower flange  24  of the fan  20 . 
         [0018]    Also referring to  FIG. 5 , the elastic bent plates  34  are received in the mounting grooves  3260  of the frame  32 . Each elastic bent plate  34  includes a C-shaped deforming portion  342 , and two pressing portions  344  extending from two ends of the deforming portion  342 . The deforming portion  342  is received in the first circular portion  3263  of the corresponding mounting groove  3260  of the frame  342 , and the two pressing portions  344  are received in the second sector-shaped portion  3264  of the mounting groove  3260  of the frame  342 . 
         [0019]    Also referring to  FIG. 7 , each fastener  36  includes a block  362 , an operating portion  364  extending upwardly from a top face of the block  362 , and a truncated sector-shaped protrusion  366  and a generally cylindrical connecting portion  368  both protruding downwardly from a bottom face of the block  362 . A sloping surface  3620  is formed at a lateral side of the block  362 , the sloping surface  3620  facing generally towards the inner side of the frame  32 . A top side of the operating portion  364  slopes downwards towards the sloping surface  3620 . The top side of the operating portion  364  is knurled or grooved to facilitate frictional contact with a user&#39;s fingertip. The connecting portion  368  includes a cylindrical base post  3682 , and a buckle  3684  formed at a bottom end of the base post  3682 . The connecting portion  368  defines two perpendicularly intersecting slots  3685  through the buckle  3684 , thereby dividing the buckle  3684  into four spaced locking parts. Each locking part includes an elastically deformable arm  3686  extending down from the bottom end of the base post  3682 , and an enlarged head  3687  extending from a bottom end of the arm  3686 . The four heads  3687  of the four locking parts cooperatively form a generally plug-shaped (or stopper-shaped) configuration. 
         [0020]    When the connecting portion  368  of each fastener  36  is extended downwardly through the through hole  3262  of the corresponding mounting groove  3260  of the frame  32 , the buckle  3684  of the connecting portion  368  is forced by an inner wall of the through hole  3262  to elastically deform radially inwardly, thereby closing the slots  3685 . After the heads  3687  of the buckle  3864  have completely passed through the through hole  3262 , the buckle  3864  elastically rebounds to its original state and the heads  3687  are buckled on a bottom face of the mounting portion  326 . Thereby, the fastener  36  is pivotally coupled to the frame  32  at the connecting portion  368 , and the fastener  36  can pivot on the base post  3682  of the connecting portion  368  in the through hole  3262 . 
         [0021]    Referring back to  FIG. 5 , the deforming portion  342  of each elastic bent plate  34  is received in the first circular portion  3263  of the corresponding mounting groove  3260 , and surrounds the base post  3682  of the connecting portion  368  of the corresponding fastener  36 . The protrusion  366  of the fastener  36  is received in an inner side of the second sector-shaped portion  3264  of the mounting groove  3260 , while the pressing portions  344  of the elastic bent plate  34  are received in an outer side of the second sector-shaped portion  3264  of the mounting groove  3260 . Put another way, the protrusion  366  of the fastener  36  and the pressing portions  344  of the elastic bent plate  34  are together received in the second sector-shaped portion  3264  of the mounting groove  3260 , with the protrusion  366  of the fastener  36  located nearer to the side wall  324  of the frame  32  than the pressing portions  344  of the elastic bent plate  34 . In one embodiment, an inner one of the two pressing portions  344  of the elastic bent plate  34  elastically abuts an outer lateral side of the protrusion  366  of the fastener  36 . 
         [0022]    In assembly, the clasps  328  of the frame  32  are clasped in the locking grooves  140  of the heat sink  10  to fix the fan holder  30  on the heat sink  10 . The fan  20  is pushed downwardly towards the frame  32 , so that the lower flange  24  of the fan  20  is received in the receiving space  323  of the frame  32 , and the locating posts  327  of the frame  32  extend in the locating holes  26  of the lower flange  24  of the fan  20 . In this process, the lower flange  24  of the fan  20  downwardly pushes the sloping surfaces  3620  of the blocks  362  of the fasteners  36  to cause the fasteners  36  to pivot outwards on the base posts  3682  of the connecting portions  368  relative to the frame  32  from original first positions to second positions. 
         [0023]    In the first position, the pressing portions  344  of each elastic bent plate  34  are received in the second sector-shaped portion  3264  of the mounting groove  3260 , with a largest gap defined between the two pressing portions  344  of the elastic bent plate  34 . In one embodiment, the inmost pressing portion  344  of each elastic bent plate  34  exerts a slight resilient force on the protrusion  366  of the corresponding fastener  36 , to keep the fastener  36  at the first position. As the fastener  36  rotates from the first position to the second position, the inner pressing portion  344  of the elastic bent plate  34  is elastically pushed outwardly by the protrusion  366  of the fastener  36  towards the outer pressing portion  344  of the elastic bent plate  34 . Thus, in the second position, the inner pressing portion  344  of the elastic bent plate  34  is elastically deformed towards the outer pressing portion  344  of the elastic bent plate  34 , with a smallest gap defined between the two pressing portions  344  of the elastic bent plate  34 . 
         [0024]    When the lower flange  24  of the fan  20  is completely received in the receiving space  323  of the frame  32 , the lower flange  24  no longer contacts the sloping surface  3620  of the block  362  of each fastener  36 , and so there is no longer any force acting on the sloping surface  3620  of the fastener  36 . The inner pressing portion  344  of the elastic bent plate  34  rebounds and pushes the protrusion  366  of the fastener  36  towards the side wall  324  of the frame  32 , and the fastener  36  rotates from the second position back to the first position. In the first position, the bottom face of the block  362  abuts the top face of the lower flange  24  of the fan  20 , so that the lower flange  24  of the fan  20  is sandwiched between the supporting plate  322  of the frame  32  and the blocks  362  of the fasteners  36 . Simultaneously, the coil springs  33  in the locating grooves  325  of the frame  32  are compressed and exert an upward resilient force on the bottom face of the lower flange  24  of the fan  20 , so that the fan  20  is firmly fastened to the frame  32  by the fasteners  36 , and vibration and noise generated by the fan  20  are thereby reduced. 
         [0025]    Disassembly of the fan  20  from the fan holder  30  of the heat dissipation device can be readily performed. A user can turn the operating portion  364  of each fastener  36  to cause the fastener  36  to pivot outwardly on the connecting portion  368 . Thus, the fastener  36  is caused to pivot from the first position to the second position. That is, the operating portions  364  of the fasteners  36  are turned outwards to cause the blocks  362  of the fasteners  36  to disengage from the lower flange  24  of the fan  20 . Then, the fan  20  is automatically pushed to move upwardly by the coil springs  33 . Thus, the fan  20  can be detached from the fan holder  30 . 
         [0026]    It is believed that the disclosure and its 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 hereinbefore described merely being preferred or exemplary embodiments of the invention.