Patent Publication Number: US-2007115642-A1

Title: Fastening member for use in a heat-dissipating device

Description:
FIELD OF THE INVENTION  
      The invention relates to a fastening member, and more particularly to a fastening member for use in a heat-dissipating device for easily securing a base plate onto a mounting surface.  
     BACKGROUND OF THE INVENTION  
      Technological progress in the electronic field results in wide employment of variety of chipsets in many electronic devices for computing or executing many operations. During operation of the chipset, a relatively large amount of heat is generated that may affect the stability of computing process. In order to provide a stable function of the chipset, an operation temperature is generally required. Traditionally, a heat-dissipating device is usually provided above the chipset so as to dissipate the intensive heat toward an outer environment of the electronic device.  
       FIG. 1  is a perspective and exploded view of a conventional heat-dissipating device  10  that utilizes high conductive metal material and that is generally produced by extrusion method. The conventional heat-dissipating device  10  includes a base plate  101 , and a plurality of cooling fins  102  extending vertically from an upper surface of the base plate  101 . The chipset (not shown) is disposed below the base plate  101  in such a manner to abut tightly against the base plate  101  such that the heat generated due to operation of the chipset is transferred to the cooling fins  102  via the base plate  101 .  
      In order to maintain tight engagement between the chipset and the base plate  101 , a fastening member  11  is usually used in the conventional heat-dissipating device  10 .  
      The fastening member  11  is made from an elongated metal wire that is twisted and bent, and includes a middle wire section  111  and two distal wire sections  112 . The middle wire section  111  is disposed at lower ends of the cooling fins  102  so as to fix the base plate  101  within the conventional heat-dissipating device  10 . Each of the distal wire sections  112  is formed with a hook for engaging a chipset seat or a holding element of the printed circuit board so as to dispose the base plate  101  in tight abutment with the chipset, thereby transferring and conducting the heat from the chipset toward the cooling fins  102 .  
       FIG. 2  is a lateral side view illustrating how the fastening member  11  fastens the base plate  101  onto the printed circuit board in the conventional heat-dissipating device  10 . Some of the cooling fins  102   a  are formed with protrusions  103  at the lower ends thereof. The protrusion  103  of the respective cooling fin  102   a  cooperates with the upper surface of the base plate  101  to define a gap therebetween.  
      In use, the middle wire section  111  of the fastening member  11  is inserted into the gap of the cooling fins  102   a . Since each of the distal wire sections  112  define an angle with the middle wire section  111  in a plane transverse to the base plate  101 , the distal wire sections  112  can be pressed downward so as to engage the aforementioned chipset seat or the holding element, thereby retaining the base plate  101  securely on the chipset.  
      It is noted that the spacing distance S 1  or S 2  between two adjacent cooling fins  102 ,  102   a  is increased due to presence of the protrusion  103  at the lower end of the respective cooling fin  102   a . Moreover, the increased distance S 1  or S 2  facilitates mounting of or removal of the middle wire section  111  to and from the protrusions  103  of the cooling fins  102   a.    
      As is known in the art, the larger the contact area of the cooling fins  102  is exposed to the atmosphere, the more heat dissipating efficiency the conventional heat-dissipating device  10  may have. Increase in the spacing distance S 1  or S 2  results in the decrease in the numbers of the cooling fins  102 , which, in turn, lowers adversely the heat dissipating ability of the conventional heat-dissipating device  10 .  
      The more the electronic technology advances, the chipsets are disposed in the trend to be produced in compact size as well as in the multifunction direction. The heat generated from these chipsets is tremendously high, and causes a burden for the chipset. Therefore, it is the object of the manufacturers to produce the electron devices in the compact size within the allowed and limited space of the electronic device.  
     SUMMARY OF THE INVENTION  
      The object of the present invention is to provide a fastening member for use in a heat-dissipating device such that the fastening member can easily and stably secure a base plate without altering the structure of the heat-dissipating device.  
      In one aspect of the present invention, a fastening member is provided for use in a heat-dissipating device that includes a base plate for disposing on a mounting surface and a plurality of cooling fins extending upwardly from the base plate to define a first channel and a second channel on an upper surface of the base plate. The fastening member includes a first portion adapted to be disposed in the first channel and having an engaging element for engaging a lower surface of the base plate adjacent to one end thereof, a second portion adapted to be disposed in the second channel and extending integrally from the first portion, and a third portion extending integrally from the second portion. The first and second portions are located in a plane, which cooperates with the third portion to define an angle between the plane and the third portion. The third portion has a hook for securing the base plate onto the mounting surface.  
      In a second aspect of the present invention, a fastening member is provided for use in a heat-dissipating device that includes a base plate and a plurality of cooling fins extending upwardly from the base plate to define a first channel and a second channel on an upper surface of the base plate. The fastening member is adapted to be disposed in the first and second channels and having two ends, each of which is formed with a hook for fixing the base plate onto a mounting surface. The fastening member further includes an engaging element for engaging a lower surface of the base plate adjacent to one end thereof. The engaging element is adapted to be exposed from the cooling fins at the one end of the base plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which:  
       FIG. 1  is a perspective and exploded view of a conventional heat-dissipating device;  
       FIG. 2  is a lateral side view of the conventional heat-dissipating device;  
       FIGS. 3A and 3B  respectively show exploded and perspective views of the first embodiment of a heat-dissipating device of the present invention;  
       FIG. 4A  is a lateral side view of the first embodiment of the heat-dissipating device of the present invention shown in  FIG. 3B ;  
       FIG. 4B  is a top view of the first embodiment of the heat-dissipating device of the present invention shown in  FIG. 3B ;  
      FIGS.  5  is an exploded view of the second embodiment of the heat-dissipating device of the present invention;  
       FIG. 6A  is a lateral side view of the second embodiment of the heat-dissipating device of the present invention shown in  FIG. 5 ;  
       FIG. 6B  is a top view of the second embodiment of the heat-dissipating device of the present invention shown in  FIG. 5 ; and  
       FIGS. 7 and 8  respectively show two modifications of a fastening member  6  employed in the heat-dissipating device of the present invention.  
    
    
     DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS  
       FIGS. 3A and 3B  respectively show exploded and perspective views of the first embodiment of a heat-dissipating device  20  of the present invention, and includes two fastening members  21 .  
      The heat-dissipating device  20  is generally made from high conductive metal materials, such as aluminum, copper or brass. The first embodiment of the heat-dissipating device  20  is preferably produced by extrusion method, and includes a base plate  201  and a plurality of cooling fins  202  extending upwardly or vertically from the base plate  201 . The base plate  201  can be integrally formed or separately formed with the cooling fins  202 . A heat-generating member (not visible) is disposed below the base plate  201  in such a manner to be in tight abutment with the base plate  201 . In the first embodiment, a chipset serves as the heat-generating member and generates intensive heat during operation. The intensive heat is transferred to the base plate  201  due to tight abutment, is latter to the cooling fins  202  which dissipate the intensive to an outside environment. The cooling fins  202  are formed on the base plate  201  in array and define a gap between adjacent two of the cooling fins  202 . In other words, the cooling fins  202  define a first channel  203  and a second channel  204  on an upper surface of the base plate  201 . Each of the first and second channels  203 ,  204  extends in a direction perpendicular to each other.  
      The fastening members  21  fastens the base plate  201  securely on the chipset (not shown). Each of the fastening members  21  is made from metal materials, such as alloy or stainless steel, and has flexibility and a restoration force so that its initial shape may change upon receipt of an applied force. The fastening member  21  can retrieve its initial shape when the applied force is removed. Each of the fastening members  21  is formed by bending and twisting an elongated metal string, and includes a first portion  211 , a second portion  212  and a third portion  213 . The first portion  211  is disposed in the first channel  203 , and has an engaging element  2111  for engaging a lower surface of the base plate adjacent to one end thereof (see  FIG. 3B ). The second portion  212  is disposed in the second channel  204 , and extends integrally from the first portion  211 . The third portion  213  extends integrally from the second portion  212 . The first and second portions  211 ,  212  are located in a plane, which cooperates with the third portion  213  to define an angle lesser than 180°. The degrees of aforementioned angle can be altered depending on the type of metal from which the fastening member  21  is constructed. The third portion  213  has a hook  2131  for securing the base plate  201  onto the mounting surface (not shown). Preferably, the hook  2131  of the third portion  213  has a C-shaped configuration when viewed from one specific viewing angle.  
      Referring to  FIG. 3B , when the fastening members  21  are utilized in the heat-dissipating device  20  of the present invention, the engaging element  2111  of the first portion  211  is exposed from the cooling fins  202  at one end of the base plate  201  for engaging the lower surface thereof. The base plate  201  has a projection  205  protruding outwardly from the end to permit engagement of the engaging element  2111  of the first portion  211  in order to secure the base plate  201  tightly onto the mounting surface of a printed circuit board (not shown).  
       FIGS. 4A and 4B  are lateral side and top views of the first embodiment of the heat-dissipating device of the present invention shown in  FIG. 3B . From these Figures, one can observe that the first portion  211  extends in the first channel  203 , the second portion  212  extends in the second channel  204  and while the engaging element  2111  of the first portion  211  is exposed from one end of the base plate  201 .  
      Furthermore, the first and second portions  211 ,  212  located in the first plane can be arranged to define 90°. The second and third portions  212 ,  213  cooperatively define 90° therebetween. Since each of the fastening members has several bent ports and when the fastening members  21  are disposed on the base plate  201  in order to secure the same, the base plate  201  is prevented from moving in the opposite sides since the first and second portions  211 ,  212  are confined in the first and second channels  203 ,  204  of the cooling fins  202 . After assembly of the fastening members  21  on the base plate  201 , the first portion  211  and the third portion  213  provides two counteract forces that press the base plate  201  tightly against the mounting surface so as to provide stability of the base plate  201  on the mounting surface. Note that mounting of the base plate  201  on the mounting surface by u sing the fastening members  21  can be conducted easily. The structure of the base plate  201  and the cooling fins  202  needs not be altered unlike to the prior art heat-dissipating device. Therefore, the manufacturing cost for producing the heat-dissipating device of the present invention can be reduced remarkably. In the heat-dissipating device of the present invention, the number of the cooling fans can be increased or the spacing distance between adjacent two of the cooling fins can be altered so as to enhance the heat dissipating ability.  
       FIG. 5  shows the second embodiment of the heat-dissipating device of the present invention, and includes a base plate  301  and a plurality of cooling fins  302  extending vertically from an upper surface of the base plate  301  to define the first channel  303  and the second channel  304  transverse to the first channel  303 . Each of the fastening members  31  has a first portion  311 , a second portion  312  and a third portion  313 . The first portion  311  is disposed in the first channel  303 , and has an engaging element  3111  for engaging the lower surface of the base plate  301  adjacent to one end thereof. The second portion  312  is disposed in the second channel  304 , and extends integrally from the first portion  311 . The third portion  313  extends integrally from the second portion  312 . The first and second portions  311 ,  312  are located in the same plane, which cooperates with the third portion  313  to define an angle lesser than 180°. The degrees of aforementioned angle can be altered depending on the type of metal from which the fastening member  31  is constructed. The third portion  313  has a hook  3131  for securing the base plate  301  onto the mounting surface (not shown).  
       FIGS. 6A and 6B  are lateral side and top views of the second embodiment of the heat-dissipating device of the present invention shown in  FIG. 5 . From these Figures, one can observe that the first portion  311  extends in the first channel  303 , the second portion  312  extends in the second channel  304  and while the engaging element  3111  of the first portion  311  is exposed from one end of the base plate  301 . The first and second portions  311 ,  312  are located in the same plane and can be arranged to define 90° therebetween. The second and third portions  312 ,  313  can be arranged to define 90° therebetween. When the fastening members  31  are disposed on the base plate  301  in order to secure the same, the base plate  301  is prevented from moving in the opposite sides since the first and second portions  311 ,  312  are confined in the first and second channels  303 ,  304  of the cooling fins  302 . After assembly of the fastening members  31  on the base plate  301 , the first portion  311  and the third portion  313  provide two counteract forces that press the base plate  301  tightly against the mounting surface.  
      Note that in the second embodiment, the configuration of the cooling fins  302  is somewhat changed and the structure of the fastening members  31  is consequently changed so as to dispose the first and second portions  311 ,  312  in the first and second channels  303 ,  304  defined by the cooling fins  302  on the upper surface of the base plate  301 .  
      The structure of the fastening members should not to limited only to the above embodiments. However, the spirit and scope of the present invention should encompass many other modifications as shown in  FIGS. 7 and 8 .  
      Referring to  FIGS. 7 and 8 , the engaging element  4 ,  5  of the fastening member is shaped as a “T” or an inverted “J” Letters respectively so long as it can engage the lower surface of the base plate  301 .  
      While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.