Abstract:
An expansion enclosure allows additional expansion cards to be used with a computer system. The enclosure exhibits a small footprint (e.g., one rack unit, or 1¾ inches) for installation in a rack or other area in which space is limited. The enclosure accepts one or more (e.g., four) expansion cards, which are connected to a removable expansion card cage. The removable cage forms part of the structure of the enclosure and provides strength and rigidity. A stabilizer may be removably but securely installed in the enclosure to stabilize or hold the removable cage as a card is installed in or removed from the cage.

Description:
BACKGROUND  
         [0001]    This invention relates to the field of computer systems. More particularly, a removable card cage is provided for a computer equipment enclosure for connecting one or more computer expansion cards to a computer system.  
           [0002]    Computer systems are often configured with a limited number of slots or connectors for installing expansion cards designed to expand the computer system&#39;s functionality, such as memory boards, cards for interfacing peripheral devices, etc. Once the original slots are populated, additional functionality cannot be added without removing an existing card. This limits the flexibility and use of the system.  
           [0003]    In some systems, a full-size “riser” card having multiple slots or connectors for expansion cards may be installed in one original slot of a computer system motherboard, thereby allowing multiple cards to be connected through one original slot. However, to accommodate such a riser card, the computer system must be relatively large in size, both vertically to accommodate the riser card and horizontally to accept any cards connected to the riser card. Computer system heights are often measured in rack units, particularly when mounted in a rack or other enclosure, wherein one rack unit is equal to approximately 1¾ inches. A computer system that can accommodate a full-size riser card may thus need to be on the order of three, four or more rack units tall, thereby consuming precious room in a computer rack or other equipment enclosure in which space is limited.  
           [0004]    In some computer system environments, space is at a premium. Systems in such environments may be unable to accommodate full-size riser cards yet may still require added functionality. Or, even if a system can accommodate a riser card, there may be a need for more expansion cards than can be connected to it. For example, in the communications industry a great number of communication connections may be needed within the limited space of a computer system chassis, and a significant number of expansion cards may be needed to provide those connections. Existing solutions to these problems tend to require considerable amounts of space and labor.  
           [0005]    In addition, it can be difficult to install an expansion board in typically computer system enclosures. It may be particularly difficult to connect an expansion card to a riser card, especially if the riser card is already installed or hosts one or more other expansion cards.  
         SUMMARY  
         [0006]    In one embodiment of the invention, an enclosure for computer expansion cards is provided. The expansion card enclosure may be coupled to a computer system, or included within a computer system, to expand the number of cards that can be used with the computer. The expansion card enclosure thus allows functionality to be added to a computer system by adding expansion cards not to a motherboard, but rather to a discrete interface sub-assembly.  
           [0007]    In this embodiment, the enclosure is low in height (e.g., one rack unit), thereby making it suitable for use in a computer equipment rack or other location where efficient use of space is a significant concern. The enclosure provides connections (e.g., slots) for multiple cards, and is connected to a computer system through a suitable interface, such as PCI (Peripheral Component Interconnect), SCSI (Small Computer System Interface), etc.  
           [0008]    An enclosure for expansion cards in a present embodiment of the invention includes a removable expansion card cage in which expansion cards may be installed horizontally, thereby allowing the enclosure to be only one rack unit high. The expansion cage may be easily removed to allow installation of the cards and then returned to its operational position. In one implementation, one or more fans are attached to the removable cage. Electrical and data connections between the removable cage and the enclosure are made via releasable connectors, and the cage may be removed and replaced with little effort.  
           [0009]    In one embodiment of the invention, a stabilizer may be incorporated into the enclosure to facilitate installation and/or removal of expansion cards. In this embodiment, the stabilizer engages and steadies the expansion card cage while a card is installed (or removed), thereby providing a stable platform and facilitating card manipulation. 
       
    
    
     DESCRIPTION OF THE FIGURES  
       [0010]    [0010]FIG. 1 is a rear perspective view of an expansion card enclosure, including a removable expansion card cage and a stabilizer, in accordance with an embodiment of the present invention.  
         [0011]    [0011]FIG. 2A is another view of the expansion card enclosure of FIG. 1, demonstrating the removable nature of one or more components, in accordance with an embodiment of the invention.  
         [0012]    [0012]FIG. 2B is an expanded view of a stabilizer for facilitating the installation or removal of an expansion board in an embodiment of the invention.  
         [0013]    [0013]FIG. 3 depicts the expansion card enclosure of FIG. 1, in which a stabilizer is employed to stabilize the removable cage to facilitate the insertion or removal of an expansion card.  
         [0014]    [0014]FIG. 4 is another view of the expansion card enclosure of FIG. 1, wherein a removable card cage is stabilized to facilitate manipulation of an expansion card.  
         [0015]    [0015]FIG. 5 is a front view of an expansion card enclosure comprising a removable card cage and a stabilizer, in accordance with an embodiment of the invention.  
     
    
     DETAILED DESCRIPTION  
       [0016]    The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of particular applications of the invention and their requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.  
         [0017]    The environment in which a present embodiment of the invention is implemented may incorporate a general-purpose or special-purpose computer. Details of such devices (e.g., processor, memory, data storage, display) may be omitted for the sake of clarity.  
         [0018]    In one embodiment of the invention, an expansion card enclosure is provided for housing multiple expansion cards for augmenting the functionality of a computer system. The expansion card enclosure may be implemented as an integral portion of a computer system or may be implemented as a separate housing, for connection to a computer system. Multiple expansion card enclosures may be cascaded or may be simultaneously connected to one computer system to further increase the number of expansion cards with which a computer system may be augmented.  
         [0019]    The expansion card enclosure includes a removable cage or assembly comprising one or more slots for connecting the expansion cards. In one implementation, the cage comprises four card slots. The expansion cards and slots may be configured according to virtually any type of interface, such as PCI (Peripheral Component Interconnect), SCSI (Small Computer System Interface), EISA (Extended Industry Standard Architecture), etc.  
         [0020]    The removable cage not only provides connections for the expansion cards, but also adds rigidity to the enclosure and enables a small form factor. A portion of the cage may serve as a constituent portion of one or more walls of the enclosure and/or provide internal support. In one embodiment of the invention, the enclosure is just one standard rack unit tall (e.g., approximately 1¾ inches), thereby making it usable in a computer equipment rack while occupying minimal space.  
         [0021]    The expansion card slots of the removable cage may be aligned horizontally, or substantially horizontally, to permit the one rack unit height. A rack-mountable version of the enclosure may be approximately nineteen inches wide, while the depth of the enclosure may depend upon a user&#39;s specifications (e.g., to match other equipment). One or more fans may be attached to the removable cage to help ensure proper air flow around the cards. LEDs (light emitting diodes) designed to indicate an enclosure status, signal a fault in a component of the enclosure, or provide other information may be placed on or in the front and/or rear walls of the enclosure.  
         [0022]    The expansion card enclosure of one embodiment of the invention may also include a stabilizer for holding or engaging the removable cage while an expansion card is installed or removed. This eliminates the need for a user to attempt to hold the cage while simultaneously manipulating a card. Illustratively, the stabilizer may stabilize the expansion cage in an upright position, thereby allowing a card to be installed vertically. After the cage is configured with cards, it may be installed in the enclosure in a horizontal operating orientation.  
         [0023]    [0023]FIG. 1 depicts an expansion card enclosure according to one embodiment of the invention. In this embodiment, enclosure  100  comprises base  102 , removable expansion card cage  104 , power supply  106 , connection module  108 , stabilizer  1   10  and cover  116 . Card cage  104  comprises central member  140  with multiple riser cards  142 , front cross-member  146  and rear cross-member  148 . As shown in FIGS.  2 - 5 , elements of enclosure  100  other than just expansion cage  104  may be removable or replaceable (e.g., power supply  106 , connection module  108 , stabilizer  110 ).  
         [0024]    Base  102  of enclosure  100  may incorporate one or more prongs, tongues or other means to engage card cage  104  when the cage is installed. The cage may include corresponding slots, holes or grooves to receive the prongs. For example, in the embodiment of FIG. 1, prong  120  of enclosure base  102  engages a hole in the bottom of central member  140  of card cage  104 , while prongs  122  engage slots  124  in rear cross-member  148 . In this embodiment, the rear cross-member of the removable cage serves as a portion of the rear wall of enclosure  100 . Captive screws may be used (e.g., with connection module  108 , stabilizer  110 , cage  104 , etc.) to facilitate the releasable installation of various elements of the expansion enclosure.  
         [0025]    After removable card cage  104  is installed, connection module  108  can be extended or slid into position to mate connector  132  with connector  134 . In this embodiment of the invention, connection module  108  routes electrical power from power supply  106  to card cage  104 . Connection module  108  and/or another element of enclosure  100  may provide data connectivity (e.g., for indicating an enclosure status to be signaled with a status indicator such as an LED). In one alternative embodiment of the invention, connection module  108  may be more permanently attached to removable card cage  104  or power supply  106 .  
         [0026]    Each riser card  142  of removable card cage  104  in FIG. 1 comprises one or more card slots  144 , which may be aligned substantially horizontally. The illustrated embodiment features two slots on each riser card. For each card slot  144 , front cross-member  146  of cage  104  comprises a corresponding card guide  150  (for receiving cards of suitable length). Rear cross-member  148  of the cage includes an aperture  152 , for each slot  144 , for accessing a data connector of a card when the expansion card enclosure is assembled and prepared for operation, and may also incorporate card guides. Front cross-member  146  may support one or more fans  154 . In other embodiments, fans may be located elsewhere and may or may not be directly attached to the removable card cage.  
         [0027]    When installed, removable card cage  104  engages prongs  120 ,  122  as described above, and flanges  126  of base  102  receive side edges of the rear of the cage. More particularly, the cage may be installed horizontally upon base  102 , and then slid rearward to engage prongs  120 ,  122  and flanges  126 . Thus, expansion card enclosure  100  is strengthened and made rigid, when the card cage is installed, by the position of removable cage  104  between base  102  and cover  116 . The rear of the cage serves as part of the rear of the enclosure, and may include spring clips (not shown in FIG. 1) on the top and/or bottom of rear cross-member  148  to help reduce EMI (electromagnetic interference) and/or provide grounding when the enclosure is sealed.  
         [0028]    [0028]FIG. 2A demonstrates the removable nature of card cage  104 , power supply  106 , connection module  108  and stabilizer  110 . FIG. 2B provides an expanded view of stabilizer  110 . In the embodiment of the invention depicted in FIG. 2B, stabilizer  110  includes mount  114  for supporting an enclosure status indicator—such as an LED or diode and associated circuitry. The mount may comprise a vertical support arising from the base portion of the stabilizer, or comprise a portion of such a vertical support. A status indicator may be affixed to the support.  
         [0029]    [0029]FIG. 3 demonstrates the use of stabilizer  110  of enclosure  100  to stabilize card cage  104  during the insertion or removal of an expansion card.  
         [0030]    As shown in FIG. 2B, the base or primary surface of stabilizer  110  includes lead-in tab or flange  112 . A standoff may be installed beneath or as part of the base, and stabilizer  110  may be secured to base  102  of enclosure  100  using a captive screw or other permanent or semi-permanent means. A hook or prong on the underside of the stabilizer (not shown in FIG. 3) may be configured to engage base  102  of the expansion card enclosure.  
         [0031]    In FIG. 3, card cage  104  is stabilized, in a vertical position, by inserting one side of rear cross-member  148  under lead-in tab  112 , while front cross-member  146  rests on base  102 . When the card cage is installed in an operational position (i.e., horizontal), the sides of rear cross-member  146  engage flanges  126 , as described above. Tab  112 , and/or the adjacent edge of the stabilizer, may be beveled or rounded to facilitate engagement of removable cage  104 .  
         [0032]    Stabilizer  110  provides a stable platform for the cage during card manipulation, and limits movement of the cage upward or sideways, regardless of whether any expansion cards are connected to the cage. Thus, instead of trying to hold the cage with one hand while adding or removing a card with the other, a user may stabilize the cage with stabilizer  110  and use both hands to add or remove the card. This may reduce the likelihood of damaging a card or the cage (e.g., by bending one of the cross-supports) or misaligning a card. In other embodiments of the invention, stabilizer  110  may be located in a different area of the enclosure. FIG. 4 shows enclosure  100  with cage  104  populated with multiple expansion cards and stabilized upon stabilizer  110  for card manipulation.  
         [0033]    [0033]FIG. 5 provides a front view, of enclosure  100 , including card cage  104 , power supply  106 , connection module  108  and stabilizer  110 .  
         [0034]    The foregoing descriptions of embodiments of the invention have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the invention to the forms depicted or disclosed. Accordingly, the above disclosure and accompanying figures are not intended to limit the invention; the scope of the invention is defined by the appended claims.