Abstract:
A heat dissipation device is provided for dissipating heat generated by a plurality of electronic components mounted on a printed circuit board and having different heights. The heat dissipation device includes a connecting member and a first base mounted on the connecting member and located at above one of the electronic components. A number of joining members extend through the printed circuit board and engage with the first base to assemble the first base on the one of the electronic components on the printed circuit board. A distance between the first base and the one of the electronic components is adjustable by adjusting the joining members to make the first base intimately contact with the one of the electronic components.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to heat dissipation devices and, more particularly, to a heat dissipation device thermally contacting with a plurality of electronic components having different height, to dissipate heat of the electronic components, simultaneously. 
         [0003]    2. Description of Related Art 
         [0004]    Generally, a heat dissipation device thermally contacts with electronic components mounted on a printed circuit board (PCB) to dissipate heat of the electronic components. The heat dissipation device comprises a base contacting with the electronic components and a plurality of fins extending upwardly from a top surface of the base. When the electronic components have different heights, the base of the heat dissipation device is not able to tightly contact with all of the electronic components at the same time; as a result, a large heat resistance will exist between the electronic components and the base, which will adversely affect the heat dissipation of the electronic components. 
         [0005]    What is needed, therefore, is a heat dissipation device which can effectively dissipate heat generated by electronic components on a printed circuit board, wherein the electronic components have different heights. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is an assembly view of a heat dissipation device in accordance with an embodiment of the present disclosure and a printed circuit board separated from the heat dissipation device. 
           [0007]      FIG. 2  is an inverted view of the heat dissipation device of  FIG. 1 , but a second base of a second heat sink is taken away from the second heat sink for clarity. 
           [0008]      FIG. 3  is a partly exploded view of the heat dissipation device of  FIG. 1 , wherein first fins are separated from a first heat sink of the heat dissipation device. 
           [0009]      FIG. 4  is a partly exploded view of the heat dissipation device of  FIG. 1 , wherein the first heat sink is separated from a connecting member of the heat dissipation device. 
           [0010]      FIG. 5  is an exploded view of pins and a first base of the first heat sink of  FIG. 4 . 
           [0011]      FIG. 6  is a cross-sectional view of the first heat sink, when the first heat sink is assembled to the connecting member. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIGS. 1-2  illustrate a heat dissipation device in accordance with the present disclosure. The heat dissipation device thermally contacts a first electronic component  200  and a second electronic component  300  mounted on a printed circuit board (PCB)  100  to dissipate heat generated by the first and second electronic components  200 ,  300  at the same time. The first electronic component  200  is shorter than the second electronic component  300 . The heat dissipation device comprises a connecting member  10 , a first heat sink  20  and a second heat sink  30 . The first and second heat sinks  20 ,  30  are mounted on the connecting member  10  and thermally contact with the first and second electronic components  200 ,  300  of the PCB  100 , respectively. 
         [0013]    Referring to  FIGS. 3-4  also, the second heat sink  30  comprises a second base  31 , a number of second pins  32 , a heat pipe  35  and a number of second fins  33 . The second base  31  thermally contacts with the second electronic component  300  and is located at a bottom side of the connecting member  10 . The second pins  32  are secured on the second base  31  and extend through second through holes  13  of the connecting member  10 . The second fins  33  each have a T-shaped configuration and are parallel to and spaced from each other. A number of holes  330  are defined in each of the second fins  33 . The second pins  32  extend through the holes  330  of the second fins  33  and interferentially engage with the second fins  33 . Thus, the second fins  33  are secured on the second pins  32 . The heat pipe  35  is L-shaped and comprises an evaporating section  351  received in a groove  310  of the second base  31  and a condensing section  355 . The heat pipe  35  thermally contacts with the bottom surface of the connecting member  10  on which the second fins  33  are located to transfer heat to the second fins  33 . Two screws  60  extend through the PCB  100  and engage in mounting holes  313  defined two diagonally opposite ends of the second base  31  to mount the second heat sink  30  on the PCB  100 . The bottom surface of the second base  31  intimately and thermally contacts with the second electronic component  300 . 
         [0014]    The connecting member  10  is a metallic plate and has a rectangular configuration. A first end of the connecting member  10  defines an opening  14  to receive a fan (not shown). A second end opposite to the first end defines a number of first through holes  12 . The second through holes  13  are located between the opening  14  and the first through holes  12 . The first and second through holes  12 ,  13  are provided for assembly of the first and second heat sinks  20 ,  30  to the connecting member  10 . The first through holes  12  are arranged in matrix and located at a corner of the second end. A flange  120  extends upwardly from an edge of the first through hole  12 . The second through holes  13  are located near the opening  14 . 
         [0015]    Referring to  FIGS. 5-6  also, the first heat sink  20  comprises a first base  21 , a number of first pins  22  secured on the first base  21 , a number of first fins  23  assembled on the first pins  22  and a number of elastic members  40  enclosing the first pins  22  and sandwiched between the first base  21  and the bottommost first fin  23 . Each of the first base  21 , the first pins  22  and the first fins  23  is made of material having good heat conductivity, such as aluminum or copper. In this embodiment, the elastic member  40  is a helical spring and can be compressed along an axial direction thereof. 
         [0016]    The first base  21  comprises a rectangular bottom plate  211  contacting with the first electronic component  200  and a top cover  215  secured on and covering the bottom plate  211 . A number of columned studs  212  protrude on a top surface of the bottom plate  211  along an edge of the bottom plate  211 . The studs  212  are integrally formed on the bottom plate  211  by punching. Thus, a concave  213  is defined in a bottom surface of the bottom plate  211  corresponding to each of the studs  212 . The top cover  215  is a rectangular plate and defines a number of orifices  218  corresponding to the studs  212  of the bottom plate  211  to receive the studs  212 . A diameter of each orifice  218  is slightly larger than that of each stud  212 . A number of through holes (not labeled) are defied in the top cover  215 . Each through hole has a circular recess  216  defined in a bottom of the top cover  215  and a circular passage  217  defined in a top of the top cover  216 . The recess  216  and a corresponding passage  217  communicate with each other and are coaxial. The recess  216  has a diameter larger than that of the passage  217 . Two sleeves  219  with internal thread extend integrally and downwardly from two diagonally opposite ends of the top cover  215 . When the top cover  215  and the bottom plate  211  are assembled together, the sleeves  219  extend downwardly beyond a bottom face of the bottom plate  211 . Two screws  50  extend through the PCB  100  and engage with the sleeves  219  to fix the first heat sink  20  on the PCB  100 . 
         [0017]    Each of the first pins  22  is columned and comprises a head  28  and a body  29  extending upwardly from a central portion of the head  28 . Understandably the first pin  22  can be square, prism or other shape in alternative embodiments. The head  28  has a diameter larger than that of the body  29 . The first pin  22  has a T-shaped profile in lengthwise cross-section (shown from  FIG. 6 ). The head  28  has a height larger than a depth of the recess  216 . The head  28  is received in the recess  216  of the top cover  215  of the first base  21  and beyond the recess  216 . Preferably, the head  28  is 0.05-0.15 mm higher than the recess  21 . The body  29  is slightly smaller than the passage  217  of the top cover  215 . The head  28  is larger than the passage  217 . 
         [0018]    The first fins  23  are parallel to and spaced from each other. A number of holes  230  are defined in the first fins  23  to allow the bodies  29  of the first pins  22  to extend therethrough. The bodies  29  interferantially extend through the holes  230 , thereby securing the first fins  23  on the bodies  29  of the first pins  22 . 
         [0019]    After the second heat sink  30  is assembled on the PCB  100 , the first heat sink  20  is assembled on the PCB  100  too to thermally contact with the first electronic component  200  of the PCB  100 . When the first heat sink is assembled, the bodies  29  of the first pins  22  extend through the passages  217  of the top cover  215  from bottom to top, and top portions of the heads  28  are received in the recesses  216  of the top cover  215 . The bottom plate  211  is pressed upwardly toward the top cover  215  whereby the bottom plate  211  contacts bottom ends of the heads  28 . Each of the heads  28  is pressed to deform and expand to fill a gap between the head  28  and the recess  216 . In this state, a bottom surface of the head  28  is coplanar to the bottom surface of the top cover  215 . Thus, the bottom plate  211  intimately contacts the bottom surface of the top cover  215  and the heads  28  of the first pins  22 . Simultaneously, the studs  22  of the bottom plate  211  are received in the orifices  218  of the top cover  215 . The studs  22  are punched to deform thereby to rivet into the orifices  218  and intimately joint the bottom plate  211  and top cover  215  together. In this state, the first base  21  and the first pins  22  are assembled together. The bodies  29  of the first pins  22  extend through the first holes  12  of the connecting member  10  from bottom to top. The elastic members  40  are positioned around periphery of the flanges  120  of the connecting member  10  and abut against a top surface of the connecting member  10 . The bodies  29  extend through the holes  230  of the first fins  23  and interferentially engaged with the first fins  23 . The elastic members  40  abut against the bottommost first fin  23 . The bottom plate  211  of the first heat sink  20  is arranged on the first electronic component  200 . Two screws  50  extend through the PCB  100  and engage with the sleeves  219  of the bottom plate  211  to fix the first heat sink  20  on the PCB  100 . A distance between the bottom plate  211  and the first electronic component  200  is adjustable by tightening the screws  50 . The elastic members  40  are compressed by the first base  21  and the bottommost fin  23 . Thus, a force afforded by the elastic members  40  pushes the first base  21  and the connecting member  10  toward the first electronic component  200  to make the first base  21  intimately connect with first electronic component  200 . 
         [0020]    It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.