Abstract:
An assembly comprising a circuit board, a socket, and an electronic device. The socket is connected to the circuit board and comprises a surface having a plurality of receptacles into which are disposed a plurality of connector pins from the electronic device. A heat sink is in thermal contact with the electronic device and has a footprint extending beyond both the electronic device and the socket. A locking lever pivotally connects to an arm extending from the socket to a position outside of the footprint of the heat sink.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a continuation of copending application Ser. No. 10/036,165, filed on Dec. 26, 2001, which is hereby incorporated by reference herein. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND  
         [0003]    The present invention generally relates to methods and apparatus for installing heat sinks and processors to a circuit board. More particularly, the present invention relates to methods and apparatus for attaching a processor to a heat sink to form an assembly that can then be attached to a circuit board without any tools or risk of damage to the processor.  
           [0004]    Conventionally, a processor is mounted in a socket on a printed circuit board that includes a plurality of integrated circuits secured thereto. Heat dissipation affects the operation of the processor and thus it is desirable to have a highly effective heat sink for the processor. These types of heat sinks are often attached to the processor by way of a thermal interface, which serves to attach the heat sink to the processor and provide a path for thermal energy. In high power processor applications, the heat sink required for a given processor may have a much larger footprint than the processor itself.  
           [0005]    The processor is first installed into a socket on the circuit board and retained in place by a lock mechanism that is often integral to the socket. Most processors are installed onto a socket by hand and it is up to the installer to ensure proper alignment of the processor pins with the holes on the socket. Because the pins on a processor are often very small and fragile, it is not uncommon to damage one or more pins during installation. If the pins of the processor are damaged they must be repaired and the processor will likely have to be replaced.  
           [0006]    Once the processor is installed, the heat sink is then affixed to the top of the processor by the thermal interface material. The size of the heat sink may be large enough to prevent unlocking and removing of the processor while the heat sink is installed. Therefore, the heat sink must be removed from the processor before the processor can be removed from the socket. There exists no method or apparatus in the prior art to easily separate the heat sink from the processor once the thermal interface has been heated. Often this removal is performed using brute force, often resulting in damage to the processor during the removal process.  
           [0007]    Therefore, there remains a need in the art for methods and apparatus that allow for processors and heat sinks to be installed and uninstalled from a circuit board without risking damage to the processor. It is also desirable to have a processor and heat sink assembly that can be installed and uninstalled without tools and without relying on the steady hand of a technician to prevent damage to the processor chip. The preferred embodiments of the present invention described below overcome these and other deficiencies of the prior art while focusing on these needs.  
         BRIEF SUMMARY  
         [0008]    The preferred embodiments of the present invention overcome the deficiencies of the prior art noted above, by providing a heat sink processor assembly that can be easily installed and uninstalled from a circuit board configured to accept the assembly. Accordingly, one preferred embodiment of the heat sink assembly comprises a heat sink component and an alignment cage that is attached to the base of the heat sink. The heat sink assembly further comprises a plurality of alignment pins affixed to the base of the heat sink that align to features built into the circuit board. The alignment cage further comprises an attachment point for releasably attaching a processor with sufficient strength to maintain contact between the processor and the heat sink but also allowing the processor to “float” in order to properly interface with mating holes on a socket, given all the tolerance variations possible in the system. The alignment cage comprises features that, along with the pins on the processor, interface with a specially designed socket to properly align and seat the processor chip. Thus, the processor, heat sink assembly, and socket all comprise features that work together to allow easy engagement and disengagement of the processor without tools and without having to pry the heat sink from the processor.  
           [0009]    Once the processor is attached to the alignment cage, the heat sink assembly is prepared for installation onto the circuit board. The circuit board has a plurality of holes arranged to accept the alignment pins. Inserting the alignment pins into the chamfered holes on the circuit board provides a rough alignment of the processor to a socket also mounted to the circuit board. As the alignment pins are inserted into the holes, the alignment cage interacts with the socket providing an intermediate alignment between the processor and the socket. The intermediate alignment provides an alignment that is within the tolerances that allow the inherent alignment features of the processor and the socket to provide the final alignment of the processor pins with the chamfered receiving holes on the socket. Once the processor is fully engaged with the socket, the processor is electrically coupled to the socket by actuating a socket locking lever that is extended beyond the heat sink volume. The heat sink and socket assembly can be uninstalled by reversing this procedure.  
           [0010]    Accordingly, this particular embodiment of the present invention provides a heat sink and processor assembly that can be installed onto a circuit board with a socket that comprises unique features that allow for installation the neither requires tools nor damages the processor. Therefore, the embodiments of the present invention provide a heat sink/processor assembly and circuit board and socket arrangement that decrease the difficulty and costs of installing and maintaining heat sinks and processors. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is an isometric view of one embodiment of the heat sink assembly without a processor installed;  
         [0013]    [0013]FIG. 2 is an isometric view of one embodiment of the heat sink assembly with a processor installed;  
         [0014]    [0014]FIG. 3 is a plan view of one embodiment of an alignment cage and alignment pins;  
         [0015]    [0015]FIG. 4 is a plan view of one embodiment of a socket installed on a circuit board;  
         [0016]    [0016]FIG. 5 is a schematic elevation view of a heat sink assembly interfacing with a socket and circuit board in a first position;  
         [0017]    [0017]FIG. 6 is a schematic elevation view of a heat sink assembly interfacing with a socket and circuit board in a second position;  
         [0018]    [0018]FIG. 7 is a schematic elevation view of a heat sink assembly interfacing with a socket and circuit board in a third position;  
         [0019]    [0019]FIG. 7A is a schematic elevation view of the a processor pin interfacing with a receptacle on the socket;  
         [0020]    [0020]FIG. 8 is a schematic elevation view of a heat sink assembly interfacing with a socket and circuit board in a fully engaged position; and  
         [0021]    [0021]FIG. 9 is a side view of the socket.. 
     
    
     NOTATION AND NOMENCLATURE  
       [0022]    Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, computer companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ” Assembly is used to define the assembly of a heat sink and a processor chip. Board is used to refer to an integrated circuit board.  
         [0023]    In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness.  
         [0024]    In order to fully describe the preferred embodiments of the present invention, reference will be made throughout this description to a heat sink and processor assembly that shows a typical 603 pin processor chip, but the concepts described herein are applicable to other types of computers and integrated circuit chips, as well as non-computer applications. Embodiments of the present invention may find particular use with integrated circuit chips other than processors as well as other components that interface by way of a multi-pin connection. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein.  
       DETAILED DESCRIPTION  
       [0025]    Referring now to FIGS. 1 and 2, a heat sink assembly  10 , constructed in accordance with the preferred embodiment, comprises an alignment cage  12 , and a plurality of alignment pins  14  attached to a heat sink  10 . The alignment cage  12  comprises a plurality of locating tabs  16 ,  18  that surround a receptacle  24  sized to receive a processor chip  26 . As shown in FIG. 2, receptacle  24  comprises a pair of clips  20 , or some other mechanism for retaining the processor chip  26  in place. As best seen in FIG. 1, receptacle  24  is preferably adapted to receive a thermal interface film  22  to enhance the thermal connection between the processor chip  26  and the heat sink  11 . Processor chip  26  is installed with pins  28  facing away from the heat sink  11  and once installed is ready for installation onto a circuit board.  
         [0026]    [0026]FIG. 3 and FIG. 4 depict, respectively, schematic representations of the interfacing portions of heat sink assembly  10  with a processor  26  installed and the corresponding interfacing portions of circuit board  30  and chip socket  34 . Circuit board  30  has a plurality of holes  32  that are sized and spaced to accommodate alignment pins  14 . Alignment pins  14  entering holes  32  serves as the initial gross alignment of the processor chip  26  and the socket  34 . As the heat sink assembly  10  is lowered, locating tabs  18  interface with corresponding slots  36  integrally constructed into socket  34  and tabs  16  are spaced so as to fit along edges  38 ,  40  of socket  34 . The interaction of locating tabs  16 , 18  and the socket  34  ensures that processor pins  28  will enter the corresponding receptacles  42  built into socket  34 . In addition, clips  20  have clearance slots  35  built into socket  34 . Once processor  26  is fully engaged into socket  34 , locking lever  44  is actuated, which locks the processor in place and couples the processor to the circuit board. Locking lever  44  located at the end of an extended arm  47  so that it can be accessed when the heat sink assembly  10  is installed.  
         [0027]    [0027]FIGS. 5-8 depict the sequence of events that occur as assembly  10  is installed onto circuit board  30 . FIG. 5 shows assembly  10  positioned just prior to engaging circuit board  30 . Alignment pins  14  are positioned by the user to align with holes  32  located on circuit board  30 . Holes  32  preferably have a chamfered opening  48  that, along with chamfered head  50  of pin  14 , directs each pin  14  into its corresponding hole  32 . Assembly  10  preferably comprises at least two alignment pins  14  to positively locate the assembly  10  on the circuit board  30 . It is also preferred that the alignment pins  14  are arranged so that the assembly  10  can only be installed in one position relative to board  30 . This is preferably accomplished by using three alignment pins  14 , which allow assembly  10  to be installed in only one position and provide a stable base for the assembly  10 .  
         [0028]    [0028]FIG. 6 depicts assembly  10  as it is aligned with board  30  and as the alignment cage  12  begins to interface with socket  34 . Alignment tabs  18  fit into slots  36  on socket  34  to position assembly  10  in one direction, while positioning in the perpendicular direction is controlled by alignment tabs  16  contacting the outside edges of socket  34 . Alignment tabs  16 , 18  work to refine the alignment of assembly  10  to socket  34  and place the processor  26  in position to properly engage the socket. Cage  12 , by way of clips  20 , retains the processor  26  but preferably provides the compliance to allow the processor to easily interface with socket  34 . It is preferred that the alignment tabs  16 , 18  serve to further refine the alignment of processor  26  with socket  34  to a position to enable the processor pins  28  to easily engage receptacles  42  without damaging the pins.  
         [0029]    [0029]FIG. 7 and FIG. 7A show the assembly  10  as processor pins  28  are aligning with mounting holes  42 . Each mounting hole  42  has a chamfered entrance  43  that combined with the chamfered, or pointed, end  29  of pin  28  allows the pin to smoothly enter the mounting hole.  
         [0030]    [0030]FIG. 8 shows the assembly  10  fully assembled onto board  30  and socket  34 . In this position the processor is fully. seated on socket  34 , and the socket can be moved to the closed position. In the fully seated position, as shown in FIG. 7, alignment pins  14  preferably penetrate through board  30  and have an area of reduced diameter  50  onto which a clamp (not shown) can be affixed to secure heat sink assembly  10  to board  30 .  
         [0031]    [0031]FIG. 9 shows an end view of socket  34  with locking lever  44  shown in both an open position  46  and a closed position  48  (shown in phantom lines). In both open  46  and closed  48  positions, locking lever  44  is elevated above, and at an angle to, board  30 . This provides clearance beneath locking lever  44  for other components to be mounted to board  30  and makes it easier for a user to manually actuate the lever. Referring back to FIG. 2, cage  12  preferably comprises a tab  52  located at one corner of the cage. The closed position  48  of locking lever  44  is arranged so as to interfere with tab  52  and prevent insertion of processor  26  into socket  34  if it is closed.  
         [0032]    In an alternative embodiment, the position of the alignment pins and the holes may be reversed with the pins being mounted on the board and the holes being in the heat sink assembly. This arrangement may be used if there is limited access to the underside of the board. Other embodiments may include sockets that provide all alignment features necessary to seat the chip, therefore eliminating any alignment features on the board, or heat sink and processor assemblies that are used to install multiple chips simultaneously. It is also contemplated that there are many different arrangements of alignment pins and alignment tabs that will perform identical functions to the embodiments described above.  
         [0033]    It is preferred that the heat sink and the alignment pins be constructed of metal. The alignment cage and socket are preferably constructed from a thermoplastic material such as is common in computer components.  
         [0034]    Therefore the preferred embodiments of the present invention described above provide a method and apparatus for simultaneously installing a processor chip and a heat sink to a circuit board without needing any tools. The embodiments of the present invention provide apparatus that ensure the proper engagement of the processor chip to a socket, therefore preventing any damage to the chip during the installation sequence. The above described embodiments also provide an apparatus that limits the installation errors that can be made by a user by providing parts that only interface in one method and can not be installed improperly. Therefore, the embodiments of the present invention decrease the costs of installing and maintaining high performance processor chips that require very large heat sinks.  
         [0035]    The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. For example, a rail designed in accordance with the present invention could be used in a non-computer environment as a drawer slide or other such device. It is intended that the following claims be interpreted to embrace all such variations and modifications.