Abstract:
A fastener for attaching a circuit board to a chassis has a head section for engaging the circuit board, a tail section for engaging the chassis, and a spring section to urge the head into engagement with the circuit board.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to computers and computer manufacturing and, more particularly to, an apparatus, method and system to easily attach and electrically ground a circuit board to a computer chassis.  
         BACKGROUND OF THE INVENTION  
         [0002]    Computer manufacturers rely primarily on large product volume to compete with other manufacturers in their industry. Consequently, manufacturing techniques must use efficiently components and labor to produce a competitive product. Each manufacturing step or component within the computer assembly adds production costs, which might otherwise contribute to profits. Attaching a circuit board to the chassis, for example, requires typically several components and multiple manufacturing steps.  
           [0003]    The circuit board is usually attached to the chassis with screws through a standard pattern of screw holes. Each screw must be installed through the circuit board holes and into a threaded metal standoff. The standoff serves to attach and electrically ground the circuit board to the chassis when the screw is tightened. Unfortunately, installing repetitively each standoff and screw consumes valuable manufacturing time and increases the possibility of damage to the circuit board by the screw installation tools.  
           [0004]    Screws also have an additional disadvantage when used for computer manufacturing because they are usually small and metallic. Small screws are difficult to capture and place within a computer assembly. Dropped screws may become lodged within circuitry on the circuit board. Because screws are usually metallic, a dropped screw has the potential to short circuit and damage the delicate circuitry on the circuit board.  
           [0005]    Additionally, computer consumers often upgrade their own computers by replacing components within their existing chassis. Consumers often lack the proper tools and skill necessary to efficiently service their computer. Removing the old circuit board and replacing it with a new circuit board increases the possibility that the consumer will damage one or both circuit boards during the upgrade process. The possibility for damage may be especially appreciated considering that the circuit-board is attached to the chassis with several tiny screws through holes that are located proximate vital computer circuitry. If the consumer&#39;s screwdriver slips, the resulting damage to the circuit board could be substantial.  
           [0006]    It would, therefore, be desirable to have a fastener that does not require repetitive manufacturing steps to install the circuit board in the chassis. Additionally, there is a need for a fastening system that does not increase the number of components, such as screws, for example, in the computer assembly. Also, there is a need for fastening system that does not increase the likelihood that a consumer will damage the computer while performing upgrades.  
         SUMMARY OF THE INVENTION  
         [0007]    According to one embodiment of the present invention, a fastener for attaching a circuit board to a chassis has a head section for engaging the circuit board, a tail section for engaging the chassis, and a spring section to urge the head into engagement with the circuit board is disclosed.  
           [0008]    According to another embodiment of the present invention, a method for attaching a circuit board to a chassis includes the step of positioning one or more pivoting fasteners within the chassis is also disclosed. The pivoting fasteners have a head section, a tail section, and a spring section. The tail sections of the pivoting fasteners are connected to the chassis. One or more circuit board mounting holes are engaged with the head sections of the pivoting fasteners. The circuit board is then releasably locked to the chassis.  
           [0009]    Another embodiment of the present invention is a system for attaching a circuit board to a chassis that has one or more pivoting fasteners connected to the chassis and a releasable locking circuit board retainer. The pivoting fasteners capture the circuit board through mounting holes in the circuit board. The circuit board retainer holds the circuit board against tension, which results from springs attached to the pivoting fasteners. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:  
         [0011]    [0011]FIG. 1 is a perspective view of a fastener that depicts one embodiment of the present invention;  
         [0012]    [0012]FIG. 2 is a perspective view of a retainer that depicts an embodiment of the present invention;  
         [0013]    [0013]FIG. 3 is a perspective view of a computer chassis that depicts an embodiment of the present invention;  
         [0014]    [0014]FIG. 4 is a side view of a fastener in an open position that depicts an embodiment of the present invention;  
         [0015]    [0015]FIG. 5 is a side view of a fastener in a closed position that depicts an embodiment of the present invention;  
         [0016]    [0016]FIG. 6 is a perspective sectional view of a computer chassis that depicts an embodiment of the present invention;  
         [0017]    [0017]FIG. 7 is a perspective sectional view of a computer chassis that depicts an embodiment of the present invention; and  
         [0018]    [0018]FIG. 8 is a perspective view of a computer chassis that depicts an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Although making and using various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.  
         [0020]    Referring to FIG. 1, a fastener  10  has a body  12 . The body  12  has a tail  14 , which may include a spring  16 . The fastener  10  may be retained in a computer chassis (illustrated in FIG. 3) by inserting the tail  14  and the spring  16  into predetermined locations. The spring  16  may help retain and position the fastener  10  in an orientation that may facilitate installation of a circuit board (illustrated in FIGS. 4-8).  
         [0021]    The material selected for the fastener  10  may enhance the spring constant of the spring  16 . The fastener  10  may be fabricated from a single piece of die-stamped sheet steel, for example. The fastener  10  may also be molded plastic or another suitable material. If the fastener  10  is die-stamped sheet steel, it may be formed using a metal break or other manufacturing technique known by those having ordinary skill in the metal fabrication art. Forming the body  12  and the spring  16  from the same material may reduce costs and increase manufacturing efficiency. However, those having ordinary skill in the manufacturing art will appreciate that the body  12  and the spring  16  may be formed from dissimilar materials.  
         [0022]    The spring  16  acts against the chassis through a fulcrum  18 , which helps retain the fastener  10 . A stop  20  also helps position the fastener  10  and prevents over-travel. The spring  16  urges the body  12  into an orientation that is generally offset from vertical. During assembly, the offset vertical orientation of body  12  aids in positioning the circuit board and provides resistance, which secures the circuit board.  
         [0023]    A head  22  is connected to the body  12  to interface with the circuit board. The head  22  may have, for example, a hook  24  to help retain the circuit board and a guide  26  to aid in positioning the circuit board. The guide  26  may be shaped to reduce snagging of wires and other components within a computer assembly. Reducing or eliminating sharp edges on the guide  26  may also protect a technician or consumer who is manufacturing or servicing the computer assembly.  
         [0024]    The fastener  10  may also include a grounding arm  28 . The grounding arm  28  may serve to electrically ground the circuit board to the chassis. A foot  30  may electrically contact the chassis while the grounding arm  28  may be urged against a grounding contact on the circuit board in a spring-like relation.  
         [0025]    Turning now to FIG. 2, depicted is another embodiment in which a retainer  32  has a retainer body  34 . A retainer foot  36  and a retainer tab  38  are attached to the retainer body  34  to secure the retainer  32  to predetermined locations on the chassis. A board retainer  40  attached to the retainer  32  may be constructed of a resilient material, which urges the board retainer  40  into retaining contact with the circuit board. Examples of resilient materials for retainer  32  may be made from mold injected plastic, die-stamped steel or machined aluminum, for example.  
         [0026]    [0026]FIG. 3 depicts a chassis  50  having multiple fasteners  10  and retainers  32 . The fasteners  10  and retainers  32  are installed on the chassis  50  at locating features  56 . The locating features  56  may be die-stamped, drilled or machined into the chassis  50  at predetermined locations, which correspond to attachment points on the circuit board.  
         [0027]    Multiple configurations of locating features  56  may be included on the chassis  50  to correspond to a variety of circuit boards. Consequently, the chassis  50  allows for versatile manufacturing processes. Different circuit boards may be easily attached to the chassis  50  by simply relocating the fasteners  10  or retainers  32  to correspond to a particular circuit board, hole or attachment point pattern. As a result, a single chassis  50  may be used to assemble multiple products having circuit boards of different sizes and shapes.  
         [0028]    The chassis  50  may have a rear panel  52  that houses I/O slots  54 . The I/O slots  54  may be aligned to the locating features  56 , which, consequently, align the circuit board with the corresponding I/O slots  54 . The I/O slots  54 , for example, may be typically die-stamped into the rear panel  52  but may also be molded, drilled, machined, or laser-cut.  
         [0029]    Turning now to FIGS. 4-6, a detailed installation of a circuit board  60  is depicted. Specifically, FIG. 4 depicts the fastener  10  in an open position. The spring  16  urges the body  12  and the head  22  of the fastener  10  into an orientation that is generally offset from vertical. A hole  62  in the circuit board  60  is placed over the head  22  of the fastener  10 . The guide  26  may prevent damage to the circuit board  60  as the hole  62  is placed over the head  22 .  
         [0030]    After the circuit board  60  is resting, generally, on the body  12  of the fastener  10 , the circuit board  60  may be pushed toward the rear panel  52 . The fastener  10  may pivot about fulcrum  18  as the circuit board  60  is moved into position. The hook  24  of the fastener  10  may restrict upward motion of the circuit board  60 . The spring  16  may resist rearward movement of the circuit board  60  and will tend to urge the circuit board  60  away from the rear panel  52 . However, the resistance of the spring  16  may act to hold the circuit board  60  against the retainer  32  (shown in FIG. 7). The tension of the spring  16  may locate the circuit board  60  and hold the circuit board  60  in position if the chassis  50  experiences environmental forces such as thermal expansion or impacts, for example.  
         [0031]    [0031]FIG. 5 depicts the fastener  10  in the closed position. The foot  30  rests against the chassis  50  and may electrically ground the fastener  10  to the chassis  50 . The foot  30  may also impart stability to the fastener  10  and structural support to the circuit board  60 . The foot  30  may also stop the fastener  10  from pivoting beyond a desired orientation, which constrains movement and helps to precisely locate the circuit board  60  on the chassis  50 .  
         [0032]    As the fastener  10  pivots about fulcrum  18 , the grounding arm  28  may be pushed into electrical contact with the circuit board  60 . The grounding arm  30  may be formed of metal, for example, and have spring-like characteristics. As a result, the grounding arm  28  may urge the circuit board  60  against the hook  24 , which may further secure the circuit board  60 .  
         [0033]    [0033]FIG. 6 depicts the circuit board  60  secured to the chassis  50  by the fasteners  10 . The location of circuit board  60  may be determined, for example, according to the location of I/O slots  54  in the rear panel  52 . Multiple locating features  56  may be pre-fabricated in the chassis  50  to accommodate circuit boards  60  of various sizes. Fasteners  10  may be inserted into locating features  56  that correspond to holes  62  in the circuit board  60 . Fasteners  10  may be relocated easily to different locating features  56  if the circuit board  60  is changed or upgraded.  
         [0034]    Turning now to FIGS. 7 and 8, the circuit board  60  is fastened to the chassis  50  and locked into place by retainers  32 . As described with reference to FIG. 2 above, the retainers  32  may have retainer feet  36  and retainer tabs  38  to secure the retainer  32  to predetermined locations on the chassis  50 . The retainer body  34  may support a portion of the circuit board  60 . The retaining body  34  may impart additional structural stability to the circuit board  60 . The board retainer  40  may secure the circuit board  60  against the spring tension in the fasteners  10 .  
         [0035]    During installation of the circuit board  60  onto the chassis  50 , the board retainer  40  may be slightly depressed. Holes  62  in the circuit board  60  are located over the heads  22  of the fasteners  10 . The circuit board  60  may then be moved toward the rear panel  52 . When the circuit board  60  is properly located, the board retainer  40  may return to its original position and contact the circuit board  60 . As a result, the board retainer  40  may restrict movement of the circuit board  60  caused by spring tension in the fasteners  10 . Conversely, the circuit board  60  may be removed from the chassis  50  by depressing the board retainer  40 , thereby releasing the tension in the fasteners  10  and allowing the circuit board  60  to be moved rearward.  
         [0036]    Although this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.