Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-05-21
2001-08-21
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S825000, C361S801000, C211S041170, C211S041200, C248S027100, C248S027100
Reexamination Certificate
active
06278614
ABSTRACT:
BACKGROUND
1. Field of the Present Invention
The present invention generally relates to the field of computer systems and more particularly to hardware and methods designed to secure computer system expansion cards in their respective connector sockets.
2. History of Related Art
Microprocessor based computer systems typically require or include facilities for connecting one or more expansion cards to the system. Expansion cards extend the capabilities of computer systems by providing dedicated hardware to achieve a variety of tasks. Graphics adapters, high speed network controllers, hard disk controllers, sound cards, and modem cards are among some of the more common types of expansion cards although those knowledgeable in the field of computer systems will recognize a wide variety of other types of expansion cards.
Typically, expansion cards are interfaced to the microprocessor (or microprocessors in a multi-processor system) by physically inserting the expansion card into an expansion card connector. In many cases, the expansion card includes facilities for making an external connection to the expansion card. A network adapter card, as an example, typically includes a socket for connecting an external cable to the adapter card. The expansion card must be maintained in a precise position such that the socket is accessible. Moreover, because external connections to expansion cards are achieved by incorporating expansion slots in the chassis of a computer system, it is important to maintain the portion of the expansion card that includes the socket or other external connector in close proximity to the chassis to minimize the gap between the expansion card and the chassis. In addition, it is important to maintain the positioning of expansion cards within their respective expansion card connector during system operation to insure reliable operation. Those familiar with expansion cards and expansion cards connectors will appreciate the ease with which a slight displacement or movement of the expansion card can result in a faulty connection. Thus, maintaining precise positioning of expansion cards is a an important issue in the design and manufacturing of computer systems. Historically, the secure positioning of expansion cards was maintained by screwing each expansion card into place with one or more securing screws. Unfortunately, the use of separate screws to secure each expansion board undesirably increases the amount of time and effort required to install, remove, replace, and otherwise service the expansion cards in a system.
A significant amount of effort has been devoted to simplifying the means by which the positioning of expansion cards is maintained. See, for example, Feightner (U.S. Pat. No. 5,694, 291) incorporating an intricately fabricated bracket apparatus to secure add-on cards in “Baby-AT” type computers; Carney (U.S. Pat. No. 5,706,173) disclosing a support and protective plate mechanism for engaging PCI cards; Carney (U.S. Pat. No. 5,673,175) teaching a complex, hinged, “double door” retainer for use with PCI cards; Lee (U.S. Pat. No. 5,575,618) reciting a cover member for securing expansion cards; Carney (U.S. Pat. No. 5,640,309) disclosing a clip mechanism for retaining PCI cards; and Holt (U.S. Pat. No. 5,601,349) disclosing a “captive latch” device for use with an expansion card cage. Unfortunately, these inventions typically require highly intricate clips, hinges, or bracket structures that introduce an undesirably expensive piece of hardware to the system component list. In addition, these inventions are typically effective at limiting expansion card movement in only one or two orthogonal directions. It would be highly desirable to introduce an easily manufactured and inexpensive expansion card retention mechanism that overcomes the limitations of the prior art.
SUMMARY OF THE INVENTION
The problems identified above are in large part addressed by a computer system including an expansion card retention bracket that secures expansion cards such as PCI cards in their respective socket connectors. The invention secures expansion cards in the preferred embodiment with a single piece of stamped sheet metal secured with a single thumbscrew. In the preferred embodiment, the invention aligns expansion cards to their respective expansion slots and restrains expansion card movement in three directions.
Broadly speaking the invention contemplates a computer system including an expansion card retention bracket. The system includes a computer chassis that includes a rear panel. The rear panel defines a set of expansion card slots. A printed circuit board is received within the chassis. The printed circuit board includes a set of expansion card connectors aligned to the set of expansion card slots. The system further includes a card retention bracket. The bracket has first and second plates that are joined at a common end. The second plate extends substantially perpendicularly from the first plate such that the bracket is L-shaped. The first plate is adapted for being removably attached to an interior surface of the rear panel of the chassis such that the second plate extends exterior to the chassis. The second plate includes a set of card retention tabs including at least one retention tab corresponding to each expansion card slot. The retention tabs are positioned within the second plate to align an expansion card to a corresponding expansion slot and to restrict movement of the expansion card when the retention bracket first plate is attached to the rear panel of the chassis and placed in a set position. In one embodiment, the first plate includes a single hole suitable for receiving a fastener, such as a thumbscrew that is operable without the aid of screwdrivers or other tools, for fastening the first plate to the chassis rear panel. In one embodiment, the rear panel further includes a vertical positioning slot suitable for receiving the single fastener. The positioning slot permits adjustment of the vertical position of the retention bracket when the single fastener is loosened such that the bracket may be moved from a set position, in which the retention tabs are in proximity to their corresponding expansion cards, to a clear position in which the retention tabs are vertically displaced from the expansion cards. In one embodiment, the retention tabs are arranged in pairs where each pair of tabs corresponds to a corresponding expansion card slot. In this arrangement, a first tab of each pair of tabs is oriented parallel to the first plate to restrict movement of the expansion card in a plane perpendicular to the chassis rear panel when the retention bracket is properly attached to the rear panel. The second tab of each pair is oriented perpendicular to the first plate to restrict movement of the expansion board in a plane approximately parallel to the rear panel. Preferably, the retention bracket including the retention tabs comprises a single piece of formed sheet metal. In one embodiment, the chassis rear panel further defines an entry slot suitable for receiving the second plate of the retention bracket when the first plate is attached to an interior surface of the chassis rear panel. In one embodiment, the second plate terminates in a flange at an end opposite the common end. The flange is suitable for gripping or handling the card retention bracket.
The present invention further contemplates a method of installing, removing, or replacing expansion cards in a computer system by loosening a single fastener accessible from an exterior of the computer system. The loosening is preferably achieved by hand where the single fastener is a thumbscrew. A card retention bracket is then moved from a set position to a clear position by moving a first plate of the bracket that is removably attached to the rear panel in a vertical direction until retention tabs formed in a second plate of the card retention bracket are clear of expansion cards received within a expansion card connectors of the computer system. After the bracket is clear of the expansion cards, the cards may
Beaman Daniel Paul
Buller M. Lawrence
Kerrigan Brian Michael
Pugley John Richard
Gaffin Jeffrey
International Business Machines - Corporation
Lally Joseph P.
Schelkopf J. Bruce
Tran Thanh Y.
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