Abstract:
The present invention is to provide a snapping device comprising a fastening resilient strip including a main body; at least one bolt parallel to the fastening resilient strip; a contact section moveable along the shank of the bolt; and a hollow support secured to a circuit board having a central hole for receiving an element (such as a CPU) mounted thereon and enabling top of the element to be in contact with a cooler mounted in the support, wherein the fastening resilient strip is secured to the support. Thus, while rotating the bolt, the contact section moves along the bolt toward the cooler due to a reaction of the main body and tightly press the cooler onto the element in an optimum contact condition.

Description:
FIELD OF THE INVENTION 
     The present invention relates to fastening of a cooler on CPU (central processing unit) and more particularly to an improved snapping device for reliably fastening the CPU cooler and increasing a heat dissipation capability of the CPU cooler. 
     BACKGROUND OF THE INVENTION 
     A conventional CPU cooling assembly is shown in FIG.  1 A. As shown, it comprises a fastening resilient strip  9  including a main body  91 , two arms  92  at both ends, and two openings  93  at both arms  92 . A hollow four-sided support  82  is provided around a plurality of apertures  86  arranged as two enclosed squares on a circuit board  81 . Two tabs  83  are formed on opposite sides of the support  82 . Further, the tabs  83  are disposed corresponding to the openings  93 . It is possible of inserting the tabs  83  into the openings  93  after a CPU  84  is secured on the apertures  86 . Also, the main body  91  is pressed on a central channel  801  of a cooler  80 . Hence, the cooler  80  is secured onto the CPU  84 . As an end, heat generated by the running CPU  84  can be driven away via the cooler  80 . 
     As stated above, the cooler  80  is secured onto the CPU  84  so as to absorb heat generated by the running CPU  84  prior to driving away heat via fins  802  of the cooler  80 . As such, an optimum pressure should be exerted on the CPU  84  by the cooler  80 . A poor heat conduction may be occurred between the cooler  80  and the CPU  84  if the pressure exerted on the cooler  80  by the main body  91  is not enough. This is true for the conventional CPU cooling assembly since the pressure exerted on the cooler  80  by the fastening resilient strip  9  is mainly caused by the fastening of the tabs  83  and the openings  93  at the arms  92 . Further, apparently such pressure is not sufficient to appropriately press the cooler  80  on the CPU  84 . 
     A solution to the above problem of insufficient pressure is illustrated in FIG.  1 B. As shown, each arm  92  is bent to form a horizontal positioning member  94  with the opening  93  provided thereat. In assembly, a plurality of screws (two are shown)  95  are driven through the openings  93  to secure the fastening resilient strip  9  to the circuit board  81 . It is advantageous since the fastening resilient strip  9  is able to exert a sufficient pressure on the cooler  80 . However, for the purpose of exerting a uniform pressure on the cooler  80  a simple single driving of either screw  95  is not adopted. Instead, a stepwise technique of advancing one screw  95  a predetermined distance and then advancing the other screw  95  the same predetermined distance in alternate is implemented until the fastening resilient strip  9  is secured to the circuit board  81 . Inevitably, it is a time-consuming process, resulting in a contradiction to mass production implemented in a long period of time. Thus, it is desirable to provide an improved snapping device in order to overcome the above drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a snapping device for reliably fastening a cooler on a CPU and increasing a heat dissipation capability of the cooler. By utilizing this snapping device, it is possible of overcoming the drawback of the first prior art such as poor heat conduction between the cooler and the CPU since there is no sufficient pressure exerted on the cooler and the drawbacks of the second prior art such as a uniform pressure on the cooler being difficult which in turn causes a poor heat conduction between the cooler and the CPU, and a time-consuming assembly process. 
     To achieve the above and other objects, the present invention provides a snapping device comprising a fastening resilient strip including a main body; at least one bolt parallel to the fastening resilient strip; a contact section moveable along the shank of either bolt; and a hollow support secured to a circuit board having a central hole for receiving an element mounted on the circuit board, wherein a cooler is mounted in the support and is in contact with the top of the element for dissipating heat generated by the element so as to achieve the purpose of quickly securing the fastening resilient strip to the circuit board and securing the cooler to the element on the circuit board. At this position, the fastening resilient strip is secured to the support and the contact section is on the cooler. In response to a rotation of the at least one bolt, the contact section moves along the bolt. As such, the contact section moves toward the cooler because a reaction is occurred in the main body, the cooler is pressed on the element consequently. As an end, the cooler is in an optimum contact with the element. 
    
    
     The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is an exploded view of a conventional CPU cooling assembly; 
     FIG. 1B is an exploded view of another conventional CPU cooling assembly; 
     FIG. 2 is an exploded view of a first preferred embodiment of a snapping device for cooler to be mounted on a CPU according to the invention; 
     FIG. 3A is a cross-sectional view of the assembled snapping device, cooler, and CPU shown in FIG. 2 where the cooler has not been fastened by the snapping device; 
     FIG. 3B is a view similar to FIG. 3A where the cooler has been fastened by the snapping device; 
     FIG. 4A is a cross-sectional view of a second preferred embodiment of a snapping device for CPU cooler where the cooler has not been fastened by the snapping device; 
     FIG. 4B is a view similar to FIG. 4A where the cooler has been fastened by the snapping device; 
     FIG. 5A is a cross-sectional view of a third preferred embodiment of a snapping device for CPU cooler where the cooler has not been fastened by the snapping device; and 
     FIG. 5B is a view similar to FIG. 5A where the cooler has been fastened by the snapping device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention is directed to a snapping device as shown in FIG.  2 . It comprises a fastening resilient strip  1  including a main body  10 , two arms  11  at both ends, and two horizontal positioning members  12  formed by bending the arms  11 , two bolts  2  releasably driven through the arms  11 , the bolts  2  being parallel to the main body  10 ; a contact section  3  moveable along a lengthwise direction of either bolt  2 ; and a hollow four-sided (square as shown) support  4  having a central hole  40 , the support  4  being secured to a circuit board (e.g., motherboard)  5  so that an element (e.g., CPU)  6  mounted on the circuit board  5  can be located within the central hole  40  and the heat generated by the element  6  will be dissipated as detailed below. A cooler  7  is mounted in the support  4  and is in contact with the top of the element  6 . Also, the positioning members  12  are secured to the support  4 . Next, rotate the bolts  2  to move the contact section  3  about the main body  10 . As such, the contact section  3  moves toward the cooler  7  because a reaction is occurred in the main body  10 . As a result, the cooler  7  is pressed on the element  6 , i.e., the cooler  7  is secured. 
     Referring to FIG. 2, a commercially available cooler  7  comprises a plurality of fins  70  projected upward. A straight channel  71  is formed on the center of the fins  70 . The provision of the channel  71  is to facilitate the fastening of the cooler  7  and the circuit board  5  by securing the fastening resilient strip  1  thereto. For example, in the invention the main body  10  and the contact section  3  are installed in the channel  71  for fastening the cooler  7 . Note that a plurality of variations of the main body  10 , the contact section  3 , and the bolts  2  are possible for securing the cooler  7  to the circuit board  5  as detailed below. 
     Referring to FIG. 3A, there is shown a first preferred embodiment of the invention in which the contact section  3  comprises a first contact member  31  and a separate second mating contact member  32  capable of engaging with the first contact member  31 ; one bolt  2  comprises a first shank  21 ; and the other bolt  2  comprises a second shank  22  with the contact section  3  sandwiched between the shanks  21  and  22 . In other words, a tip of the first shank  21  is engaged with the first contact member  31  and a tip of the second shank  22  is engaged with the second mating contact member  32  respectively. A first slanted surface  311  is formed on the first contact member  31  and a parallel second slanted surface  312  is formed on the second mating contact member  32  respectively. The first and the second slanted surface  311  and  312  are urged against each other when the first and the second shanks  21  and  22  are rotated. As shown in FIG. 3B, the second mating contact member  32  slides upward to lift the main body  10  while the first contact member  31  slides down toward the cooler  7 . As such, the cooler  7  is pressed on the element  6 . As a result, the cooler  7  is fastened. 
     Referring to FIG. 4A, there is shown a second preferred embodiment of the invention in which an inverted gable member  101  is formed at the center of the main body  10  with the angle thereof faced the contact section  3 . As such, the fastening resilient strip  1  is substantially shaped as an M. The bolt  2  has two thread portions advanced from both heads toward the inverted gable member  101  in which one thread portion has a spiral edge advanced opposite to that of the other thread portion. The contact section  3  comprises third and fourth contact members  33  and  34  both at the tips of the bolts  2 . The third and the fourth contact members  33  and  34  are moved toward the inverted gable member  101  as the bolt  2  is rotated as shown in FIG.  4 B. Next, the inverted gable member  101  is urged by the third and the fourth contact members  33  and  34  from opposite sides. A reaction is then occurred in the main body  10  due to the urging of the third and the fourth contact members  33  and  34 . Hence, the cooler  7  is pressed down by the third and the fourth contact members  33  and  34 . As a result, the cooler  7  is pressed on the element  6 . 
     Referring to FIG. 5A, there is shown a third preferred embodiment of the invention in which there is a plurality of oblique recesses  102  (three are shown) are spaced apart at the main body  10  facing the contact section  3 . Correspondingly, a plurality of oblique blocks  35  (two are shown) are spaced apart on the contact section  3  facing the main body  10  in which the oblique blocks  35  are disposed in the oblique recesses  102  in this state. The contact section  3  is moved along the bolt  2  as the bolt  2  is rotated as shown in FIG.  5 B. Next, the oblique blocks  35  clear from the oblique recesses  102  to move to positions each between any two adjacent oblique recesses  102 . A reaction is then occurred in the main body  10  due to the urging of the contact section  3  against the main body  10 . Hence, the cooler  7  is pressed down by contact section  3 . As a result, the cooler  7  is pressed on the element  6 . 
     Referring to FIGS. 2,  3 A,  3 B,  4 A,  4 B,  5 A, and  5 B the cooler  7  is provided on the element  6  so that heat generated by the running element  6  can be driven away via the cooler  7 . As such, an optimum pressure should be exerted on the element  6  by the cooler  7 . Thus, a poor heat conduction may be occurred between the cooler  7  and the element  6  if the pressure exerted on the cooler  7  by the main body  10  is not enough. To the contrary, the element  6  may be damaged by the cooler  7  if the pressure exerted on the cooler  7  by the main body  10  is excessively large. Preferably, a mark or scale may be labeled on the bolt  2  and another mark or pointer may be labeled on the fastening resilient strip  1  based on experimental data or experience. In use, a user simply rotates the bolt  2  until the mark (or scale) thereof is aligned with the mark (or pointer) on the fastening resilient strip  1 . At this position, the desired optimum pressure is exerted on the cooler  7  by the main body  10 . 
     Referring to FIG. 2 again, in the embodiment two openings  120  are formed at both positioning members  12 . Further, the support  4  has a plurality of threaded holes  41  (two are shown) disposed corresponding to the openings  120 . Furthermore, the circuit board  5  has a plurality of apertures  50  (only one is shown) disposed corresponding to the threaded holes  41 . Hence, a plurality of fasteners (e.g., screws (two are shown) or bolt and nut combinations)  42  may be driven through the support  4  and the circuit board  5  to secure the fastening resilient strip  1  to an abutment plate at the other side (i.e., underside) of the circuit board  5 . 
     Referring to FIG. 2 again, in the embodiment a plurality of electronic components (not shown) are provided on the circuit board  5  adjacent the element  6 . Hence, a rotation of the bolt  2  may be hindered. Preferably, a slot (e.g., hexagonal slot) is formed on the head of the bolt  2 . As such, a tool (e.g., screwdriver having a hexagonal tip) may be used to rotate the bolt  2  by exerting force on the hexagonal slot. As a result, the contact section  3  is moved along the bolt  2 . Alternatively, a polygonal (e.g., hexagonal) projection is formed on the head of the bolt  2 . As such, a tool (e.g., screwdriver having a hexagonal recessed tip or a wrench) may be used to rotate the bolt  2  by exerting force on the polygonal projection. As a result, the contact section  3  is moved along the bolt  2 . 
     While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.