Abstract:
A card based telecommunications system, which includes a chassis. A plurality of card guides positioned in an operable relationship within said chassis. A tab member proximate to each of the card guides to occupy a substantial portion of a first space to prevent a first card from entering the first space and contacting a second card.

Description:
BACKGROUND 
     1. Field of Invention 
     This invention relates to telecommunications equipment systems, and specifically to an apparatus for providing proper alignment during board insertion in a card based telecommunications equipment assembly. 
     2. Relevant Art 
     Most modern telecommunications equipment contains electronic apparatuses mounted in a chassis. The chassis generally includes, a front access, side walls, and a backplane. The chassis can be enclosed to prevent stray material from entering the chassis and damaging the electronic apparatuses, to prevent stray emission of electromagnetic energy and to enhance airflow. 
     Most chassis are formed with a series of card guides, which help direct a board into the chassis, such that connectors resident on the board are properly aligned with the appropriate corresponding connectors resident on the backplane. 
     Various features have been implemented on boards and card guides, which help to ensure that boards are not inserted into the wrong card guide. Unfortunately, there are currently no known features, which prevent boards that are misaligned while being initially inserted into the card guide from contacting adjacently positioned boards. Problems in the field resulting from this inadequacy of design can range from stripping off of components from the boards to causing shorts from one board to the next. 
     What is needed is an apparatus that directs board installers to insert the boards in the correct manner to avoid damaging adjacent boards during installation. 
     SUMMARY 
     The present invention provides an apparatus for addressing misalignment during board installation. In accordance with the present invention, the apparatus can include a tab that is formed and positioned on the side face of the card guide. The apparatus deters an installer from inserting boards in a card guide in a manner which causes the board to be misaligned. 
     In one aspect of the invention an apparatus is provided to facilitate card alignment. The apparatus can include a chassis configured to removably receive the card and a card guide positioned within the chassis which defines a first space. The apparatus also includes a tab positioned in the first space configured to prevent the card from entering the first space. 
     In another aspect of the invention, a card based telecommunications system is provided, which includes a chassis having a top wall and a bottom wall configured to receive a plurality of cards, where each card includes a faceplate. A plurality of card guides are positioned on the bottom wall in a corresponding and operable relationship to a plurality of card guides positioned on the top wall. Each of the plurality of card guides has a front face and a side face. A distance between the side face and the faceplate define a first space. A tab member proximate to each of the side faces of each of the card guides, where a major surface of the tab member is made flush with the front face of the card guide. The tab member occupies a substantial portion of the first space. 
     In another aspect of the present invention, an apparatus is provided to facilitate card alignment. The apparatus can include a chassis and a card guide positioned within the chassis to define a first space. The apparatus also includes means for preventing a first card from entering the first space and contacting a second card. 
     The apparatus of the present invention provides many advantages. For example, although boards are typically installed by experienced professionals, the apparatus can help to ensure that these installers or less experienced installers do not harm the boards during installation. Damage to boards during installation generally account for losses to companies on the order of thousands of dollars. The apparatus of the present invention can help to minimize these loses and save thousands of dollars. 
    
    
     These and other objects, features and advantages of the present invention will be more readily apparent from the detailed description of the preferred embodiments set forth below taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified perspective view of a shelf assembly in accordance with the present invention; 
     FIG. 2A is a simplified front perspective view of shelf assembly including a plurality of electronic apparatuses and card guides in accordance with an embodiment of the present invention; 
     FIG. 2B is a simplified partial front view of a portion of shelf assembly including a view of tabs, card guides, and a faceplate in accordance with an embodiment of the present invention; 
     FIG. 2C is a simplified top view of a card guide including a tab in accordance with an embodiment of the present invention; 
     FIG. 3A is a simplified perspective view of the tab and a portion of the card guide in accordance with an embodiment of the present invention; and 
     FIG. 3B is a simplified and perspective view of the tab and a portion of the card guide in accordance with an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a telecommunications equipment assembly  10  (hereinafter “shelf assembly  10 ” or “shelf  10 ”) configured in accordance with an embodiment of the present invention. In this embodiment, shelf assembly  10  can include a housing or chassis  12 , which includes several components, such as top wall  14 , a bottom wall  16 , a side wall  18 , a side wall  20 , and a back wall  22 , which collectively define an internal cavity  30 . Generally, housing  12  may be made with sheet metal, injection molded plastic, or other similarly suited structural materials. 
     Interior cavity  30  is suitable for removably receiving one or more electronic apparatuses. In one embodiment, interior cavity  30  is large enough to be capable of removably receiving electronic apparatuses. The electronic apparatuses can include, but not limited to, cPCI boards, such as those used in the Cisco Integrated Communications System (ICS) 7750 and other types of plug-in boards, which may provide a telecommunications functionality, such as IP telephony, Voice applications, multi-service routing and the like to shelf assembly  10 . 
     An access opening  24  provides access to interior cavity  30  for replacement, removal, assembly, servicing, and/or repair of the electronic apparatuses. As discussed in detail below, top and bottom walls  14  and  16 , respectively, can include guides having slots or grooves used to support, guide, and align the plug-in cards while housed in interior cavity  30 . 
     Back wall  22  can include a backplane, which is a printed circuit board that extends substantially the width of housing  12 . The backplane includes circuitry identical to circuitry in a conventional backplane well-known in the telecommunications industry, which provides electrical characteristics, such as shielding, conductor path characteristics, including controlled impedance, current carrying capacity, paths for instrument buses, data busses, unit under test (UUT) stimulus busses, and power busses. In one embodiment, the backplane provides the electrical interface between the electronic apparatus enclosed in housing  12  and external cables. 
     FIG. 2A is a simplified front perspective view of shelf assembly  10  including a plurality of electronic apparatuses  50 , such as a cPCI boards (hereinafter “board(s)  50 ”), in accordance with an embodiment of the present invention. Shelf assembly  10  also includes a plurality of card guides  52 , with card slots  53 , placed parallel to one another and positioned substantially on both top wall  14  and bottom wall  16  of chassis  12 . Card guides  52  extend inside internal cavity  30  substantially the depth of housing  12 , such that boards  50  placed into slots  53  of card guides  52  allow connector components on board  50  to be readily plugged into connectors resident on backplane  22 . Card guides  52  may be made of any suitable material, for example, plastic. 
     FIG. 2B is a simplified partial front view of a portion of shelf assembly  10  including a view of tabs  54 , card guides  52 , positioned on top wall  14  and bottom wall  16  of chassis  12 , and a faceplate  50   a  in accordance with an embodiment of the present invention. FIG. 2C is a simplified top view of card guide  52  including tab  54 . As best understood from FIGS. 2B and 2C, tabs  54  are positioned in space  60  defined between side face  59  of card guide  52  and faceplate  50   a  and between bottom wall  16  (or top wall  14 ) and the height h of card guide  52  to preclude a neighboring board from entering space  60  and contacting board  50 . 
     Tabs  54  can be made of any structurally suitable material, such as plastic or sheet metal. Tabs  54  can be molded or punched and formed using well known plastic and sheet metal forming techniques. In one embodiment, Tabs  54  can be mounted to side face  59  of card guide  52  using various mounting techniques, for example, gluing, soldering, and mechanical fastening, such as using a sheet metal screw, a rivet or similar techniques. Tab  54  can be mounted to side face  59 , such that tab  54  is flush with front face  58  of card guides  52 . In another alternative embodiment, tabs  54  may be formed during the manufacturing of card guides  52  as an integral part of the card guides (FIG.  3 A). 
     FIG. 3B is a simplified and magnified perspective view of tab  54  and a portion of card guide  52  in accordance with an embodiment of the present invention. In this embodiment, tabs  54  can be formed and punched from bottom wall  16  (or top wall  14 ) and bent about axis  68  to a position flush with front face  58  of card guide  52 . As shown in FIG. 3B, in most embodiments, the height h of tabs  54  should be no greater than the corresponding height of top surface  67  of card guide  52  (i.e., the maximum height of card guides  52 ), to ensure that tabs  54  remain within the “no component zone” or “keep-out” zone on board  50 . For example, tabs  54  can range in height h up to about 0.3 inches. Tabs  54  can be any suitable width w that ensures that space  60  (FIG. 2B) is substantially blocked to preclude entry of board  50 . For example, width w of tabs  54  should be wide enough so that distance  1  (FIG. 2C) between tab  54  and faceplate  50   a , or any portion of board  50 , is no greater than 0.06 inches. In one embodiment, width w is at least twice the material thickness t of tabs  54 . 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.