Abstract:
A card retention assembly for retaining one or more expansion cards within the chassis of an electronic device such as a computer system, server, photocopier, facsimile machine, printer, or the like includes a card retention assembly that engages the mounting bracket securing tab of an expansion card received in the chassis. In this manner, the card retention assembly at least partially restrains the tab for securing the expansion card in the chassis.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to electronic devices capable of employing expansion cards which provide specialized functions or resources to the device, or which extend the devices&#39; ability to communicate with and/or control peripheral devices, networks, or the like. In particular, the present invention relates to an electronic device having a chassis including a card retention assembly for retaining or securing expansion cards within the chassis while allowing installation and removal of the expansion cards without the use of fasteners or tools. 
     BACKGROUND OF THE INVENTION 
     Electronic devices, particularly computer systems, servers, photocopiers, facsimile machines, printers, control equipment, medical equipment, telecommunication equipment, and the like often include one or more expansion cards which provide specialized functions or resources to the device, or which extend the devices&#39; ability to communicate with and/or control peripheral devices, networks or the like. Such expansion cards typically comprise generally rectangular printed circuit boards having an edge connector formed along one side edge. The edge connector is inserted into an expansion slot disposed on a system board (often referred to in the art as a motherboard) mounted within the electronic device to couple the installed expansion card to other electronic components in the device. In typical configurations, the expansion slots are oriented so the expansion cards installed therein are arranged in a spaced apart, generally parallel array wherein end edges of the cards are aligned with each other. 
     Extending along the aligned end edges of the expansion cards are metal mounting brackets having outwardly bent tabs positioned adjacent to the side edges of the cards opposite the edge connector. When the expansion cards are installed within the chassis of the electronic device and seated in the expansion slot, these tabs rest against a ledge surface formed inside the chassis. Notches disposed in the tabs overlie and register with holes formed in the ledge surface allowing the mounting bracket to be secured to the surface by a screw or bolt extending through the tab notch and threaded into the hole. 
     Because a fastener such as a screw or bolt is used to secure the mounting bracket tab to the ledge surface, installation and removal of expansion cards is somewhat difficult and time consuming, and requires the use of tools such as a screwdriver or wrench. Consequently, it would be advantageous to eliminate the fastener, relying on the expansion slot itself to hold the expansion card in place. However, electronic devices, particularly personal computers, are often subjected to substantial shock and vibration during delivery from the manufacturer to a retailer or the consumer. If not retained therein by the fastener, this shock and vibration could cause expansion cards to become unseated from their expansion slots on the system board causing the expansion card to not function properly. Consequently, it would be advantageous to provide an electronic device having a case or housing comprising apparatus for securing expansion cards within the chassis of an electronic device and allowing quick removal and installation of expansion cards without the use of fasteners or tools. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a card retention assembly for retaining one or more expansion cards within the chassis of an electronic device such as a computer system, server, photocopier, facsimile machine, printer, or the like. In an exemplary embodiment of the invention, the chassis of the electronic device includes a tab retaining surface against which the tab of the mounting bracket of an expansion card rests when the expansion card is inserted in the chassis (i.e., seated in an expansion slot of the electronic device). A spring arm assembly is mounted to the chassis so that it may move between an open position and a closed position. The arm assembly includes a spring member suitable for engaging the tab and tab retaining surface when the arm assembly is in the closed position to at least partially restrain the tab against the tab retaining surface for securing the expansion card in the chassis. 
     It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
     FIG. 1 is a partial isometric view illustrating a computer chassis including a card retention assembly in accordance with an exemplary embodiment of the present invention wherein the card retention assembly is closed; 
     FIG. 2 is a partial isometric view of the computer chassis illustrated in FIG. 1, wherein the card retention assembly is shown open; 
     FIG. 3 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating expansion cards seated within expansion slots of a system board of the computer and retained within the chassis by the card retention assembly; and 
     FIG. 4 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating removal of an expansion card from the computer. 
     FIG. 5 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating an expansion card inserted within the computer chassis; and 
     FIGS. 6 and 7 are partial cross-sectional views of the card retention assembly of the computer chassis shown in FIG. 1, wherein the card retention assembly is shown in the open position in FIG.  6  and in the closed position in FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which is illustrated in the accompanying drawings. 
     Referring generally to FIGS. 1 through 7, a computer system  100  employing a card retention assembly  102  in accordance with an exemplary embodiment of the present invention is described. The computer system  100  includes a chassis  104  having an internal card cage assembly  106  providing a plurality of expansion slots  108  each capable of accommodating an expansion card  110  for providing functions or resources to the computer system and/or for extending the computer system&#39;s ability to communicate with or control peripheral devices coupled thereto (not shown). Each expansion slot  108  is defined by a connector or socket  112  mounted to a printed circuit board  114  disposed within the computer system&#39;s chassis  104 . When an expansion card  110  is received in an expansion slot  108 , the card&#39;s edge connector  116  is seated within the connector  112  of that slot  108  thereby coupling the expansion card  110  to the printed circuit board  114 . 
     In an exemplary embodiment, shown in FIGS. 3 and 4, printed circuit board  114  may comprise a main system board, motherboard, or the like which contains other electronic components of the computer system  100  such as the system&#39;s processor, main memory, bus controller, keyboard controller, video controller, and the like. Alternately, the printed circuit board  114  may comprise a secondary board or daughterboard mounted within the card cage assembly  106  and coupled to the computer system&#39;s motherboard. Further, in exemplary embodiments of the invention, expansion slots  108  may comprise connectors  112  suitable for mating with edge connectors  116  having various pin configurations. In such embodiments, the number of pins, and the width and depth of the pins supported by connectors  112  is determined by the interface standard utilized by the computer system bus, e.g., Industry Standard Architecture (ISA), extended industry standard architecture (EISA), Peripheral Component Interconnect (PCI), Micro Channel Architecture (MCA), Video Electronics Standards Association Local Bus (VL-BUS), or the like. 
     As shown in FIGS. 3 and 4, expansion slots  108  are oriented so that expansion cards  110  received therein are arranged in a spaced apart, generally parallel array wherein the end edges  118  of the cards  110  are substantially aligned with each other. Preferably, printed circuit board  114  is positioned within the chassis  104  so that expansion slots  108  are also sufficiently close to a wall of the chassis  104 , such as the chassis&#39; back panel  120 , to allow the mounting bracket  122  of each card  110  received within an expansion slot  108  to rest against the inner surface  124  of the panel  120 . 
     Expansion ports  126  comprised of elongated, generally rectangular apertures formed in back panel  120  are positioned adjacent to a connector  112  of printed circuit board  114 . As shown in FIGS. 3 and 4, when an expansion card  110  is seated within an expansion slot  108 , its mounting bracket  122  registers with a corresponding expansion port  126  allowing connectors  128 - 142  supported in the card&#39;s mounting bracket  122  to extend through the port  130  so they may be accessed by users of the computer system  100 . If an expansion slot  108  is empty, i.e., does not hold an expansion card  110 , an expansion port cover  144  may cover the expansion port  126  to prevent environmental contaminants from entering the chassis  104 , and/or to shield the computer system&#39;s internal electronic components from electromagnetic interference (EMI). 
     In accordance with an exemplary embodiment of the present invention, card retention assembly  102  securely retains expansion cards  110  within their respective expansion slots  108  during shipping, transport and use of the computer system  100 , while allowing installation and removal of expansion cards  110  without the use of fasteners or tools. The card retention assembly  102  also functions to secure expansion port covers  134  within empty expansion ports  126 . 
     As shown in FIGS. 2 and 5, the card retention assembly  102  includes a ledge or lip  146  extending outwardly from back panel  120  immediately adjacent to the ends of expansion ports  126 . Preferably, an aperture  148  is formed along substantially the entire length of the ledge  146  opposite expansion ports  126 . When an expansion card  110  is installed within the card cage assembly  106  (i.e., so that its edge connector  116  is fully seated in a connector  112  of an expansion slot  108  as shown in FIGS.  3  and  4 ), the card&#39;s mounting bracket  122  is positioned against the inner surface  124  of back panel  120  so that downwardly extending tab  150  may engage slot  152 , while outwardly extending tab  154  extends through aperture  148  and rests against surface  156 . 
     Short protrusions  158  extend outwardly from surface  156 . These protrusions  158  are positioned to engage notches or holes  160  formed in tabs  154  to prevent lateral movement of the expansion card  110  within its expansion slot  108 . Protrusions  158  may, in the same manner, function to prevent lateral movement of expansion port covers  144  in empty expansion ports  126 . In the exemplary embodiment shown in FIGS. 2 and 4, the protrusions  158  consist of the extruded rims of small holes formed in the surface  156  of ledge  146 . Alternately, protrusion  158  may comprise raised posts, rivets, or like structures depending on design and manufacturing preferences. 
     Referring now primarily to FIGS. 1,  2 ,  6  and  7 , expansion cards  110  are retained within expansion slots  108  by a spring arm assembly  162  mounted to the outside surface  164  of back panel  120 . In an exemplary embodiment, the spring arm assembly  162  may be moved between an closed position, shown in FIGS. 1 and 7, wherein the spring arm assembly  162  engages the tabs  154  of expansion cards  110  for securing the cards  110  within their respective expansion slots  108  (see FIGS.  3  and  4 ), and an open position, shown in FIGS. 2 and 6, wherein the tabs  154  are released, allowing expansion cards  110  to be removed and installed within the card cage assembly  106  of chassis  104 . When closed, the spring arm assembly  162  completely covers aperture  148  to prevent the intrusion of environmental contaminants into the chassis  104 , and to reduce electromagnetic interference (EMI) with the computer system&#39;s electronic components. 
     In an exemplary embodiment, shown in FIGS. 6 and 7, the spring arm assembly  162  includes a spring arm  166  formed of a thin sheet of a spring metal or like resilient, flexible material providing a spring bias tending to force the spring arm assembly  162  to the closed position. The spring arm  166  includes a first end  168  anchored to back panel  120  by fasteners  170  such as rivets, screws, bolts, or the like, and a second end  172  formed into a generally C-shaped channel  174  having inner and outer side wall portions  176  &amp;  178  and top wall portion  180 . A handle assembly  182  may be attached to channel  174  for providing a gripping surface by which the spring arm assembly  162  may be opened or closed. A surface  184  formed in the handle assembly  182  may include a hole  186  which overlies and registers with a second hole  188  formed in a bracket  190  extending from ledge  146  to receive a fastener, such as a thumb screw, screw, bolt, or the like (not shown). In this manner, spring arm assembly  162  may be locked in the closed position, for example, during shipping or transport of the computer system  100  from the manufacturer to a retailer or consumer, or to prevent accidental opening of the spring arm assembly  162  by a user or third party. 
     As shown in FIGS. 6 and 7, spring members  192  are formed in inner wall portion  176  and extend into channel  174  so that they may contact the tabs  154  of expansion cards  110  when spring arm assembly  162  is closed. When spring arm assembly  162  is closed, the spring members  192  clamp the tabs  154  and ledge  146  against the outer wall portion  178  of channel  174  so that the tabs  154  are at least partially restrained against surface  156  to prevent up and down movement of the expansion cards  110  (i.e., movement of the expansion cards  110  in directions generally perpendicular to printed circuit board  114  as shown in FIGS. 3 and 4) that could cause the card  110  to become unseated. Preferably, spring members  192  allow for variation in the height of expansion cards  110  that may be manufactured in accordance with industry standard tolerances. 
     In the exemplary embodiment of the invention shown in FIGS. 1 through 7, expansion cards  110  may be installed within the card cage assembly  106  of chassis  104  by first moving the spring arm assembly  162  to its open position, shown in FIGS. 2 and 6, by grasping handle assembly  182  and pulling outward away from back panel  120 . This action unclamps the spring arm assembly&#39;s channel  174  from ledge  146  and causes its spring arm  166  to flex in a pivotal fashion shown in FIGS. 2 and 6. An expansion card  110  may then be inserted within an expansion slot  108  of the card cage assembly  106  so that its mounting bracket  122  is positioned against a corresponding expansion port  126  in the back panel  120 . The edge connector  116  of expansion card  110  is seated within the expansion slot connector  112 . Finally, the spring arm assembly  162  is moved to the closed position, shown in FIGS. 1 and 7, wherein spring members  192  clamp the tab  154  and ledge  146  together so that the tab  154  is at least partially restrained against surface  156 . 
     Expansion cards  110  may be removed from card cage assembly  106  in a similar fashion by first moving the spring arm assembly  162  to its open position, thereby unclamping the tab  154  and ledge  146 . The expansion card  110  to be removed may then be unseating from its expansion slot connector  112  by application of an outward force on the card  110 , whereupon the spring arm assembly  162  may again be moved to its closed position. 
     In FIGS. 1 though  7 , computer system  100  is illustrated herein as having a “tower” or “mini-tower” style chassis  104 , wherein the chassis  104  is tall, narrow, and deep instead of a “desktop” style cabinet (not shown) which is instead short, wide and deep. However, it will be appreciated that the card retention assembly  102  of the present invention may be employed by computer systems  100  utilizing having a desktop style cabinet (not shown) by one of skill in the art without departing from the scope and spirit of the invention. It should further be recognized that the card retention assembly  102  of the present invention is not limited to use in computer systems, but may be utilized by any electronic device capable of utilizing expansion cards of the type described herein above. Such electronic devices may include, but are not limited to servers, photocopiers, facsimile machines, printers, televisions audio equipment, control equipment, medical equipment, and telecommunication equipment. Consequently, modification of such electronic devices to utilize the card retention assembly  102  described herein by one of skill in the art would also not depart from the scope and spirit of the present invention as defined by the appended claims. 
     It is believed that the card retention assembly of the present invention and many of its attendant advantages will be understood by the forgoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages, the form herein before described being merely an explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.