Abstract:
The specification discloses a controller housing that utilizes card guides that may be installed and removed without the use of tools. Various arrangements of the controller housing with and without the card guides allows for the controller housing to accept electronic circuit cards of varying sizes. Thus, if a manufacturer desires to increase the number of points on an input/output card, for example, those additional points need not necessarily be contained in a card having the same form factor. Instead, the manufacturer may provide a larger form factor card and that card may be inserted into the controller housing by appropriately adjusting the location of the card guide within the particular opening into which the new card is to be inserted.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application Ser. No. 60/327,923 filed Oct. 9, 2001, and which is incorporated by reference herein as if reproduced in full below. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The preferred embodiments relate generally to housings for electronic circuit cards, and more particularly, to controller housings for holding one or more electronic circuit cards. 
     2. Background of the Invention 
     Controller housings are generally known in the art that hold one or more circuit cards, referred to herein as simply “cards.” Slots are typically provided inside the housing and are spaced so that pairs of slots engage opposite edges of a card inserted in the pair of slots. The slots may be formed in card guides supported inside the housing, where the card guides are fixed to the housing or may be releasably fastened to the housing using screws or the like. 
     Controller housings are known in which the card guides are movable to accommodate different card sizes. For example, it may be necessary or desirable to replace a current card with a new card having a different size—a different form factor. To reposition a conventional card guide, if this is possible at all, a tool such as a screwdriver is needed to unfasten the card guide from the old position and refasten the card guide in the new position. Such a process is labor and time intensive. 
     Conventional controller housings are sized according to the number and size of cards needed. While additional room may be provided for changes in card size or additional cards to be added later, the additional room is limited. Accordingly, if significant card changes or additions are needed, a new housing must also be provided. 
     Thus, what is needed in the art is a mechanism whereby the card guides in a controller housing can be easily removed or relocated to accommodate varying size circuit cards. Also what is needed in the art is a controller housing that is easily expandable to accommodate additional circuit cards. 
     BRIEF SUMMARY OF SOME OF THE PREFERRED EMBODIMENTS 
     The problems noted above are solved in large part by a modular controller housing, each controller housing utilizing card guides that do not require the use of tools for removal or relocation. In the preferred embodiments, each controller housing has two elongated openings that allow for insertion of circuit cards into the interior of the housing. Each opening in the preferred embodiments is capable of accepting up to two card guides. By selectively adding and removing card guides, each opening is therefore capable of accepting varying size circuit cards. With each possible card guide installed in a particular opening, three one-third size circuit cards may be inserted into the opening, thereby coupling the cards to a back-plane board mounted within and at the rear of the controller housing. If one of the card guides is removed from the exemplary opening, then the opening is capable of accepting a one-third size circuit card, and a two-thirds size circuit card. If both card guides are removed from the exemplary opening, then the opening is capable of accepting one full size circuit card. 
     In the preferred embodiments, the card guides may be installed and removed without the use of tools. That is, the card guides preferably snap into place by use of corresponding structures on an internal surface of the respective opening, and the card guide. Addition and removal of card guides in the preferred embodiments is accomplished by snapping the card guides into or out of place. When inserted, the card guides provide slots in which circuit cards slide during insertion and removal, and rest during use. 
     The preferred embodiments also comprise a modular controller housing such that additional controller housing may be placed together to form a larger housing as needed. The combination of the modular controller housing and the card guides that allow openings in the modular housings to take on varying sizes, creates an easily expandable and versatile controller housing for electronic circuit cards. 
     The disclosed devices and methods comprise a combination of features and advantages which enable it to overcome the deficiencies of the prior art devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which: 
     FIG. 1 shows a perspective view of a controller housing of the preferred embodiments; 
     FIG. 2 shows a front elevation view of a controller housing with card guides attached therein; 
     FIG. 3 shows a rear perspective cut-away view of the controller housing of FIG. 2, a rear panel of the housing cut away; 
     FIGS. 4A and 4B show perspective views of a removable card guide; and 
     FIG. 5 shows a top plan view of the removable card guide illustrated in FIGS.  4 A and  4 B. 
    
    
     NOTATION AND NOMENCLATURE 
     Certain terms are used throughout the following description and claims to refer to particular system components. 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 . . . ”. Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a controller housing  10  constructed in accordance with the preferred embodiments. The housing  10  comprises a rear panel  12 , top and bottom panels  14 ,  16  respectively, and side panels  18 ,  20 . The various panels, in whole or in part, define an interior of the housing. Side panels  18 ,  20  may be removably attached to the housing  10  for purposes of coupling together additional controller housings. Projecting from a front side  22  of the housing are two collars  24 ,  25  defining openings  26 ,  27  for providing access to the interior of the housing. The collars  24 ,  25  are separated by a central support  28 . The controller housing  10  is preferably designed and constructed such that electronic circuit cards may be inserted and removed through the openings  26 ,  27 . The housing  10  preferably comprises a backplane board  2  (shown in dashed lines in FIG. 2 so as not to obscure the drawings) having electrical connectors thereon that mechanically and electrically couple to the circuit cards inserted through the openings  26 ,  27 . The backplane board of the preferred embodiment is held in position by a combination of shoulders  4 ,  6 , as well as stand-off  8  (and an additional stand-off not seen in the perspective view of FIG.  1 ). 
     The controller housing  10  of the preferred embodiments is capable of accepting electronic circuit cards of varying sizes; that is, having different form factors. FIG. 2 shows a front elevational view of the housing  10  of the preferred embodiments. Each opening  26 ,  27  defines an overall height H, as shown in FIG. 2, which in the preferred embodiments is approximately 8.91 inches. In an opening with no card guides  50  installed therein, a full height H circuit card may be inserted into the opening, with an upper edge of the card sliding in slot  100 , and a lower edge of the card sliding in slot  102 . The housing  10  of the preferred embodiments is also capable of accepting electronic circuit cards smaller than the full height H cards. That is, by insertion of card guides  50 , the full height openings  26 ,  27  may be divided into smaller sizes. Still referring to FIG. 2, opening  27  is shown with two card guides  50 A and  50 B installed therein. Card guides  50 , whose construction and installation will be discussed more thoroughly below, make the opening  27  of the housing  10  capable of accepting circuit cards of smaller size. FIG. 2 shows, in dashed lines, an exemplary one-third height card  60  installed in an upper-most location. In this upper-most location of opening  27 , a top edge of the circuit card slides in slot  104 , and a lower edge of the circuit card slides in slot  106  in an upper portion of the card guide  50 A. As is exemplified in FIG. 2, installing two card guides  50  in an opening  27  (or opening  26 ) of the preferred embodiments enables the opening to receive three one-third size circuit cards. If only one card guide, for example card guide  50 C in opening  26  of FIG. 2 is installed (it is noted that the card guide  50 C is shown only partially installed in FIG.  2 ), then the opening  26  is capable of accepting a one-third height circuit card, and a two-thirds height circuit card. Having thus described the versatility of the controller housing  10  of the preferred embodiments, attention is now turned to various components of the housing  10  that facilitate installation and removal of the card guides, as well as the card guides themselves. 
     In order to hold the card guides in place, each opening  26 ,  27  of the preferred embodiment has connection portions therein to facilitate releasably installing the card guides. While the portions may take many forms, in the preferred embodiments the connection portions comprise two matched sets of a card guide support track  30  and a stationary snap-lock tab  32 . The card guide support tracks  30  are seen both in the perspective view of FIG. 1, as well as the elevational view of FIG.  2 . The snap-lock tabs  32  are seen in the elevational view of FIG.  2  and the rear perspective view of FIG.  3 . Each card guide support track  30  comprises a first receiving notch or channel  34  which supports a card guide  50  when installed, and also provides a point of rotation during installation of the card guides, to be discussed more fully below. Opposite of the card guide support track  30  is a snap-lock tab  32 . 
     Referring now to FIG. 3, which shows a rear perspective view of the controller housing  10  of the preferred embodiments with the back panel  12  cut away, there is shown the snap-lock tab  32  in better detail. In particular, the snap-lock tab  32  in the preferred embodiments is a protruding tab-type structure having a notch  36  cut in a distal end thereof. Moreover, the snap-lock tab  32  has a thickness, identified in FIG. 3 as “T”, which in the preferred embodiments is approximately 0.13 inches. As will be subsequently discussed, the snap-lock tab  32  fits in mating relationship with a corresponding structure on the card support guides  50 . 
     The card guide support tracks  30 , and corresponding snap-lock tabs  32 , are spaced within each opening  26 ,  27  to define a plurality of storage spaces  46  corresponding to portions of the housing  10  interior. In the embodiment illustrated in FIGS. 1-3, two sets of tracks  30  and snap-lock tabs  32  are provided within each opening  26 ,  27  to define a total of six storage spaces  46  (three spaces  46  for each opening  26 ,  27 ). The storage spaces are illustrated in FIG. 1 using dashed lines  47 . Referring to FIG. 2, there is shown, in dashed lines, a circuit card  60  within an upper storage space in the opening  27 . In this configuration, the upper storage space is defined by the slot  104  at the upper portion of the opening  27 , and the slot  106  on a first side of the card guide  50 A, the slots thus being in functional alignment. Correspondingly, a second storage location is defined by the slot  108  in a lower portion of the card guide  50 A and slot  110  in the upper portion of card guide  50 B. Finally, a third storage location is defined by slot  112  and a lower portion of the card guide  50 B and slot  114  in the lower portion of the opening  27 . As has been previously discussed, the card guides  50 A and  50 B may be selectively removed to define a plurality of possible card sizes that could be accepted by the opening  27 . For example, if the card guide  50 B is removed, then opening  27  is capable of receiving a one-third height circuit card  60 , as well as a two-thirds height circuit card, whose card edges would slide in slot  108  on a lower part of card guide  50 B and slot  114 . Moreover, if both the card guides  50 A and  50 B were removed, a full height card could be inserted into the opening  27 , and the card edges of such a full height card would slide in slots  104  on a top portion of the opening  27  and slot  114  on the bottom portion. 
     In the preferred embodiments, card guides  50  are provided that may be snap-fit into openings  26 ,  27 . As best shown in FIGS. 4A,  4 B and  5 , each card guide  50  comprises a connection portion  52  and a card support portion  54 . The card support portion  54  may be in the form of an elongate body  56  having pairs of spaced apart walls extending from upper and lower faces of the body  56  to define slots  58 . The slots  58  are sized to closely fit the width of a circuit card  60  (shown partially inserted and in dashed lines in FIG.  5 ). 
     The connection portion  52  of each card guide  50  comprises a first tab  62  extending from a side of the card guide  50 , and a second tab  64  extending from an opposite side of the guide. The first and second tabs  62 ,  64  are sized to have widths that closely match the receiving channel  34  of the card guide support tracks  30  and the notches  36  in the snap-lock tabs  32  respectively. A stop  66  also projects from a side of the card guide  50  rearwardly of the first tab  62 , and a clip  68  is formed by a pair of closely spaced walls  70  projecting from an opposite side of the guide  50  from the second tab  62 . The clip  68  defines a gap  72  sized to accommodate the thickness “T” of the snap-lock tab  32 . A grip  74  is provided on a front end of the card guide  50  to allow the guide to be grasped and manually manipulated. 
     Each card guide  50  may be simply and easily attached within an opening  26 ,  27  without the use of tools. In the preferred embodiments, installation of the card guides  50  preferably involves a user grasping the card guide  50  at the grip  74 , and placing the card guide&#39;s elongate body  56  in the interior of the controller housing, with the card guide  50  at an angle with respect to its final position, such as card guide  50 C in FIG.  2 . As implied by the drawing of FIG. 2, in one embodiment the first tab  62  is placed within the card guide support track  30 . The axial length “L” (see FIG. 5) of the first tab  62  (defined on one end by stop  66  and on a second end by shoulder  67 ) is only slightly larger than a length (measured perpendicular to the backplane board  2 ) of the card guide support track  30 , and is approximately 20% of an overall length of the card guide. Thus, placing the first tab  62  in the card guide support track  30  aligns the clip  68  (on the opposite side of the card guide  50 ) with the snap-lock tab  32 . Once the first tab  62  is in at least semi-mating relationship with the card guide support track  30 , the user rotates the card guide  50  (with the combination of first tab  62  and card guide support track  30  being the point of rotation) until the portion of the second tab  64  that forms the clip  68  snaps into mating relationship with the snap-lock tab  32 . The rear perspective view of FIG. 3 shows the card guide  50 C with the first tab  62  in partial mating relationship with the card guide support track  30 , and the snap-lock tab  32  in partial mating relationship with the clip  68 , just prior to rotation of the card guide  50  about its axis. Likewise, card guides  50 A, B show card guides after rotation where both the first tab  62  is in mating relationship with the card guide support track  32 , and the clip  68  is in mating relationship with the snap lock tab  32 . Movement in a vertical direction is restricted by the engagement of the first and second tabs  62 ,  64 . Movement of the card guide in an axial direction (into or out of the drawing sheet of FIG.  2 ), is restricted by the engagement of the clip  68  with the snap-lock tab  32 , as well as the stop  66  and shoulder  67 . While FIG. 2 shows that the initial mating relationship should be between the first tab  62  and the card guide support track  30 , installation of the card guides of the preferred embodiment may also take place by initially engaging the clip  68  with the snap-lock tab  32 , and then rotating the first tab  62  into mating relationship with the card guide support track  30 . Thus, the combination of the channels  30  and tabs  32  of the controller housing and the tab  62  and clip  68  of the card guide  50  form a tool-less connection. 
     In the preferred embodiments, the controller housing  10  (including the tracks  30  and snap-lock tabs  32 ) and the card guides  50  are made of injection molded ABS/polycarbonate material such as Bayblend® FR110 produced by BP Chemical, having a regrind content of 20% maximum, or an equivalent. 
     The housing  10  itself may be expanded to accommodate various card requirements. As noted above, the side panels  18 ,  20  may be removed. In addition, the side of the housing to which the panel  20  was attached includes slots  74  and clips  76  (FIG.  1 ). A second, identical housing (or several identical housings)  10  may be attached to the first using corresponding slots and clips. As a result, the housing  10  may be expanded according to card needs of the controller. 
     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. It is intended that the following claims be interpreted to embrace all such variations and modifications.