Abstract:
A heat sink apparatus for use with electronic components comprises a base frame, a clipping system and a plurality of supporting members. The base frame and the clipping system and the supporting members are of unitary construction. The base frame is configured to have “i” repeatable channels with fins extended from or attached to its outside surfaces. The clipping system comprises a matrix [i, j] set of i×j spring clips. Each spring clip is configured to have partially constrained with the base frame, and to flex about an axis resiliently to effect an engaged relation to substantially fixedly maintain the electronic component in abutting relation with the inside walls of the channel. The supporting members are configured to have fixed connection with the base frame and be solderable. The heat sink apparatus&#39;s capacity of holding electronic components is scalable to accommodate upgrades and design changes of electronic products.

Description:
[0001]     This patent application is associated to the Provisional Patent Application filed on Jul. 18, 2003, Application No.: 60/488,858. 
     
    
     CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0002]     None  
       STATEMENT REGARDING FEDERAL SPONSORED RESEARCH OR DEVELOPMENT  
       [0003]     Not Applicable  
       FIELD OF THE INVENTION  
       [0004]     This invention generally relates to the art of heat sink assemblies and, particularly, to a configurable heat sink assemblies having an embedded, scalable clipping system comprising a matrix [i, j] set of i×j spring clips for attaching electronic components thereto heat sink body.  
       BACKGROUND OF THE INVENTION  
       [0005]     Heat sinks or heat sink assemblies of a wide variety of designs have been employed to dissipate heat generated by electronic components and devices on printed wiring or circuit boards to prevent the electronic components and devices from failure. More than ever before, today&#39;s electronic products are reducing the size and cost, increasing power and speed dramatically, and upgrading frequently. So that the heat sinks or heat sink assemblies used in electronic packaging must be smaller size, larger surface areas, easier assembly, lower cost and scalable to meet the trends.  
         [0006]     Generally a heat sink is a piece of part made of any thermal conductive materials, such as Copper, Aluminum and Steel, etc. For better performance and more cost effective, a heat sink usually has extended surface areas, called fins, and is made of Aluminum. A heat sink assembly comprise of at least one heat sink and some attachments, such as clip or clamp, pins or tabs, and/or fasteners, to attach electronic components or devices onto heat sink body, and to mount the heat sink assembly into a printed wiring or circuit board.  
         [0007]     On a typical printed wiring or circuit board, there may be a number of heat generating electronic components or devices. Conventionally a couple of heat sink assemblies may be used and mounted in different orientations depending upon the circuit design and&amp;layout requirements to dissipate the heat. If the electronic product is required for more power or higher speed, the heat sink on the printed wiring or circuit board may need to be changed in order to dissipate more heat generated by the devices. Thereby the circuit may need to be redesigned and re-laid out.  
         [0008]     In order to improve size, surface areas, ease of assembly and cost, more and more heat sink apparatus are constructed unitarily. An example of the latter may be seen in U.S. Pat. No. 6,201,699 and the Max Clip System™ heat sink from AAVID. These extruded heat sinks with solderable pins pressed in are good examples for improving ease of assembly and scalability, but are limited in the size, performance, mounting orientation and unitary construction. The clips for attaching electronic components or devices are separated parts, and the heat sink can only be scalable in one direction. In other words, the numbers of electronic components on heat sink can be increased only in one direction without using separate heat sinks.  
         [0009]     Accordingly, what is needed is in the art of a smaller size, larger surface areas, lower cost, universally mountable, scalable and unitarily constructed heat sink apparatus which incorporates the clipping and mounting mechanism, and be ready for attaching electronic components or devices thereon, and universally mounted onto printed wring or circuit board without requiring extra parts.  
       SUMMARY OF THE INVENTION  
       [0010]     A heat sink apparatus for use with electronic components or devices comprises a base frame and a clipping system and a polarity of supporting members. The base frame is configured to have a channel intercepted with a cylindrical cut at its bottom center and a plurality of solderable tabs attached on at least one sidewall of the channel. The channel is repeatable transversely with “i” as the numbers of channels, i=1 means only one channel in the base frame. The base frame further has fins attached to its outside surfaces. The base frame and the clipping system and supporting members are of unitary and compact construction. The clipping system comprises a matrix [i, j] set of i×j spring clips, each spring clip is configured to flex about its axis resiliently to effect an engaged relation with both sidewalls of the channel to substantially fixedly maintain the electronic components in abutting relation with the sidewalls of channel. The heat sink capacity of attaching electronic components is scalable transversely and longitudinally by altering the elements i and j in the matrix [i, j] of the clipping system to accommodate upgrades and design changes of electronic products  
         [0011]     The unitary construction for a heat sink apparatus according to the present invention avoids the necessity for additional assembly parts such as screws, nuts, bolts, washers and adhesives. The heat sink apparatus of the present invention also avoids the requirement for such separate attachments as spring clips and fixtures suitable for clipping mechanism and stabilizing heat sink assembly before being fixed on a printed wiring or circuit board. In such all-in-one solution heat sink apparatus, it greatly reduces the assembly, documentation and inventory work.  
         [0012]     It is a further object of the present invention to provide a heat sink apparatus that the assembly of clipping system, supporting members and the base frame together to create unitary construction uses the very cost effective operations without requiring expensive tooling, skilled workers and complicated fixtures. It is, therefore, an object of the present invention to provide a heat sink apparatus that is of unitary construction using cost-effective secondary assembly operation.  
         [0013]     It is yet a further object of the present invention to provide a heat sink apparatus that may be assembled with an associated electronic component without unnecessary assembly steps, such as ancillary process operations like drilling or tapping apertures.  
         [0014]     The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIGS. 1A-1B  illustrate embodiments of prior art heat sinks.  
         [0016]      FIGS. 2-3  are perspective drawings of the top and bottom views of an embodiment of the present invention before assembly with electronic components.  
         [0017]      FIG. 4  is a perspective drawing of an embodiment of a supporting member.  
         [0018]      FIG. 5A  is a perspective drawing of an embodiment of a spring clip.  
         [0019]      FIG. 5B  is a projective view drawing of an embodiment of a spring clip  
         [0020]      FIGS. 6A, 6B  and  6 C are the partial projective drawings of views illustrating how the base frame, spring clip and supporting member assembled together.  
         [0021]      FIGS. 7A, 7B  and  7 C are the perspective drawings illustrating how to attach electronic components onto the heat sink apparatus of the present invention.  
         [0022]      FIGS. 8A-8B  are the perspective drawings of two different heat sink apparatus configurations of the embodiment of the present invention after assembly with electronic components. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Referring initially to  FIGS. 1A and 1B , illustrated are examples of prior art heat sinks  200 ,  300 . The prior art heat sink  200  illustrated in  FIG. 1A  has a longitudinal spine  210  with an opposing first side  211  and second side  212 . Extending from the first side  211  of the spine  210  are electronic device support legs  220 ,  225 , configured so that each leg  220 ,  225  can support two electronic devices or components on opposing side of the support legs  220 ,  225 , as shown, an electronic component  240  mounted a clip (not shown here), Multiple cooling fins  230 ,  235  are extending from the second side  212  and first side  211  of the spine  210 . Apparently this heat sink has the disadvantages of: 1) fixed orientation mounting with given air flow direction to manipulate the printed wiring or circuit layout; 2) lack of unitary construction since the clip is a separated part; 3) secondary machining operation is required to make the port for receiving pin  221 , if the heat sink is manufactured by extrusion; and 4) the heat sink capacity for attaching electronic components is not scalable longitudinally (in the in and out paper directions).  
         [0024]      FIG. 1B  illustrates another prior art heat sink  300 . This heat sink  300  is designed so that heat-generating components  310  are mounted directly to the heat sink body  350  using clips  320 . The heat sink  300  can be fastened to a circuit or wiring board by soldering via pin  330 . This heat sink  300  also has multiple cooling fins  340  that extend from both sides of the heat sink body  350 .  FIG. 1B  reveals that this heat sink has the disadvantages of: 1) fixed orientation-mounting with given air flow direction to manipulate the printed wiring or circuit layout; 2) lack of unitary construction since the clip is a separated part; 3) heat sink assembly can not stand straight on printed wiring or circuit board before soldering, so fixtures are required; and 4) the heat sink capacity for attaching electronic components is not scalable transversally (in left and right directions).  
         [0025]     It is common practice for several heat sinks to be required on a circuit or wiring board in order to control the heat generated by multiple devices and components. It is also common that heat sink to be required to be mounted in different orientations on a circuit or wiring board to meet the circuit layout and performance. Because heat sinks generally occupy larger space than associated components on a printed wiring or circuit board, it is highly desirable that a heat sink design be compact, scalable and universally mountable while controlling heat from several devices that would otherwise require multiple heat sinks.  
         [0026]     It is obvious that a scalable and universally mountable heat sink can reduce the part counts in a circuit or wiring board assembly, therefore the cost associated to manufacturing, assembly and parts will be reduced. The present invention addresses the space, weight, scalability, flexibility and cost problems discussed above that are inherent when multiple heat sinks are used, without impairing the ultimate objective of heat control.  
         [0027]      FIG. 2  and  3  are the perspective views of a heat sink apparatus constructed according to a preferred embodiment of the present invention. In  FIG. 2  and  3  a heat sink apparatus  100  comprises a heat sink base frame  120 , and a plurality of identical support members  140  and a plurality of spring clips  160 . Heat sink base frame  120  is configured to have at least one channel  122  with two opposite sidewalls  124 ,  126  having a slot  130 ,with width “w” and a bottom side  128  intercepted with a cylindrical cut  132  with diameter “Φ”. Heat sink base frame  120  is further configured to have extended surface areas or fins  134  attached or born to its outside surfaces for better heat dissipating. The fins  134  may be fabricated by extrusion, bonding, brazing, casting, machining or any other manufacturing methods with an inexpensive, better thermal conductive material, such as aluminum. Heat sink base frame  120  is preferably constructed of an inexpensive and better thermal conductive material, such as aluminum, and fabricated by extrusion, casting, machining and the like, preferably extrusion. The support member  140  is configured for insertion into apertures in a printed circuit or wiring board for attachment within a product, as by soldering, for example. To facilitate soldering attachment, the support member  140  is preferably constructed of solderable material, such as brass or steel with tin-plated. Accordingly, support members  140  are attached with heat sink base frame  120 ; such attachment may be effected by any convenient reliable attachment means, such as riveting, screwing, staking, pressing, adhesive or the like. In heat sink assembly  100 , the attachment is effected by half shearing. Such attachment is illustrated in  FIGS. 6A, 6B  and  6 C. The spring clip  160  is configured to be confined within heat sink base frame  120 , having the degree of freedoms of sliding along and swinging about the axis of cylinder  132 ; such constrain, according to present invention, may be effected by sliding the clip  160  into cylindrical cut  132  then deforming the edges of both ends of cylindrical cut  132  to prevent clips sliding out as illustrated in  FIGS. 6A, 6B  and  6 C. The deployment of spring clips  160  in a heat sink apparatus  100  is configured in such a way as an i×j matrix [i, j] set where i is the number of the spring clips transversally and the j is the number of the spring clips longitudinally as shown in  FIGS. 1 and 2  which is a 2×2 matrix [2, 2] heat sink apparatus. The sprint clip  160  is preferably constructed of springy and resilient material, such as spring steel, sheet or wire, and fabricated by forming, stamping or any other inexpensive way.  
         [0028]      FIG. 4  is a perspective view of support member  140  constructed according to a preferred embodiment of the present invention. The support member  140  is configured to be “L” shape having a notch  142  which is configured for receiving the sheared material, a tab  144  with a hole  146 , and a shoulder  148 . Shoulder  148  is configured for resting on the surface of a printed wiring or circuit board. Tab  144  is configured for insertion into apertures in a printed wiring or circuit board for attachment within a product. To facilitate insertion, tab  144  preferably has a chamfer or round end. Hole  146  is configured to bridge solders underneath a printed wiring or circuit board to increase mechanical strength. The thickness of the support member “t” is designed to be slightly smaller than the width “w” of slot  130  on heat sink base  120 . The support member  140  is preferably constructed of solderable material, such as brass or steel with tin-plated and fabricated by stamping operation.  
         [0029]      FIG. 5A and 5B  are a perspective and projective views of spring clip  160  constructed according to a preferred embodiment of the present invention. The spring clip  160  may be manufactured from flat or round wire spring materials and is configured to be “helical torsion spring” like having a pair of moment arms  162  with cantilever beams  164 , and tooling aperture  166  each on cantilever beams  164 , and a coil  168  having an axis  169 . The outside diameter “Ψ” of the coil  168  is designed to be slightly smaller than the inside diameter “Φ” of cylindrical cut  124 . The moment arms  162  are configured to flex about axis  169 . According to the present invention, the cantilever beams  164  are designed to be “pre-distorted”. In other words, the cantilever beams  164  is not perpendicular to the moment arms  162  is, but tiled with a angle “Υ” degree in order to apply an uniform pressure on electronic devices or components, one who is skill in the art may readily perform the stress analysis to determine the Υ value of with the given clamping force.  
         [0030]      FIG. 6A, 6B  and  6 C are a perspective partially exploded view of the heat sink assembly according to the present invention, showing how to assemble support member  140  and spring clip  160  onto a heat sink base  120  to effect the unitary connection between them. For simplicity, this view only takes one channel  122  for illustration.  FIG. 6A  shows the support member  140  and the spring clip  160  are sliding into its mating apertures, slot  130  and cylindrical cut  132 , on heat sink base  120  respectively.  FIG. 6B  shows the support member  140  and the spring clip  160  are at the positions with heat sink base  120  after sliding in.  FIG. 6C  shows the shearing actions were taken to press the material of sidewall  124  into the notch  142  of support member  140  to create a sheared button  300  which stops supporting member  140  sliding back and forth, and to deform the edge of cylindrical cut  132  to create at least one bump  200  on each end, which prevents spring clip  160  sliding out so as to effect the unitary connection between supporting member  140 , spring clip  160  and heat sink base  120 . In other words, after this operation, supporting member  140  and spring clip  160  can no longer be taken apart from heat sink base  120  without destroying the heat sink assembly  100 .  
       Operation  
       [0031]     For operation, one can use the heat sink apparatus  100  in a normal manner by clipping the electronic components or devices onto the heat sink, and readily place the whole assembly  500  onto a printed circuit or wiring board for soldering operation like using any other electronic components. To clip electronic components or devices onto the heat sink apparatus  100 , one should:  
         [0032]     1). Turn the heat sink apparatus  100  upside down as shown in  FIG. 7A   
         [0033]     2). Rotate the moment arms  162  about its coil axis with a leverage tool in tooling apertures  166  so that there is a gap between the cantilever beam  164  and the sidewalls  124 ,  126  of channel  122  as shown in  FIG. 7A .  
         [0034]     3). Slide the electronic components or devices  400  into the gaps and release the moment arms  162  so that the cantilever beam  164  can push the electronic components or devices against the sidewalls  124 ,  126  of channel  120  with certain pressure to effect the heat transfer from heat generating electronic components or devices to heat sink. There may be an electrical insulating pad (not shown here) between components or devices  400  and sidewalls  124 ,  126 . The whole heat sink assembly  500  is created and comprises a heat sink apparatus  100  and plurality of electronic components or devices  400  as shown in  FIG. 7B .  
         [0035]     4). After finishing assembling the electronic components or devices onto heat sink, turn the hole assembly  500  upside as shown in  FIG. 7C  so it can be ready for plugging into a printed circuit or wiring board for soldering operation.  
         [0036]     The user can, when desired, increase or decrease the numbers of the electronic components or devices  400  in the assembly by changing the matrix element i×j values or number of spring clip  160 , with the changing of the matrix[i, j] element (i, j) values, the heat sink apparatus  100  can be configured so that it can be mounted onto a printed circuit or wiring board universally. For example a 1×2 matrix[1, 2] heat sink assembly  510 , as shown in  FIG. 8A , can be mounted transversely and a 2×1 matrix[2, 1] heat sink assembly  520 , as shown in  FIG. 8B , can be mounted longitudinally without the need to change the airflow direction coming from a fan or a blower.  
         [0037]     Obviously the present invention provides the heat sink apparatus with advantages as listed below: 
        1). Configurable and scalable     2). Universal mountable     3). Ease of assembly     4). Efficient     5). Ease of manufacturing        
 
         [0043]     Although only a few embodiments of the present invention have been described, it should be understood that the present invention be embodied in many other specific forms without departing from the spirit or the scope of the present invention. The present examples are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.