Abstract:
A retaining clip is for securing an electrical connector to be inserted through an opening formed in a panel. The retaining clip comprises a base having an aperture therethrough for receiving the free end of the electrical connector and having one or more engagement means for engaging with and holding the electrical connector. The base is shaped to contact at least a portion of the surface of the panel that it overlies. A plurality of fingers extending away from the base are displaceable to allow insertion of a mating connector and to contact the surface of the mating connector. Thus, the clip shields the surface of the mating connector with respect to the panel.

Description:
This application claims priority to prior UK patent application No. 0319033.7, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to retaining clips and in particular to retaining clips used to secure devices such as electrical connectors mounted through an aperture in the casing of a computer including servers or other electronic device. 
     In order to hold electrical connectors, such as data connectors, in position in an aperture in the casing of a computer it is well known to use pairs of c-shaped clips that abut the surface of the casing and engage either end of that portion of the electrical connector that projects beyond the aperture. U.S. Pat. No. 6,513,206 describes an alternative retaining clip which is illustrated in combination with a conventional electrical connector in  FIG. 1 . The retaining clip comprises a single planar element  1  having an aperture  2  for receiving the free end of an electrical connector  3  and locking tabs  4 ,  5 . The locking tabs  4 ,  5  are arranged to engage with detent surfaces provided on the electrical connector by means of a sliding movement in the direction of arrow A. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide an improvement on known retaining clips and in particular to provide retaining clips that contribute to the shielding of the electronic device of which the connector forms a part. 
     In accordance with the present invention there is provided a retaining clip for securing an electrical connector to be inserted through an opening formed in a panel, the retaining clip comprising a base having an aperture therethrough for receiving the free end of the electrical connector and having one or more engagement means for engaging with and holding the electrical connector, the base being shaped to contact at least a portion of the surface of the panel that it overlies; and a plurality of fingers extending away from the base being displaceable to allow insertion of a mating connector and to contact the surface of the mating connector whereby the clip shields the surface of the mating connector with respect to the panel. 
     Thus with the present invention the retaining clip provides the additional function of em shielding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is an exploded perspective view of a known retaining clip; 
         FIG. 2  is a perspective view from the front of a retaining clip in accordance with the present invention; 
         FIG. 3  is a perspective from the rear of the retaining clip of  FIG. 2 ; 
         FIG. 4  is a plan view from one side of the retaining clip of  FIGS. 2 and 3 ; 
         FIG. 5  is a perspective view from the front of an alternative retaining clip in accordance with the present invention; 
         FIG. 6  is a perspective from the rear of the retaining clip of  FIG. 5 ; and 
         FIG. 7  is a plan view from one side of the retaining clip of  FIGS. 5 and 6 . 
         FIG. 8  is a perspective view from the front of a further alternative retaining clip in accordance with the present invention; 
         FIG. 9  is a sectional view of the state where the retaining clip of  FIG. 8  and a receptacle connector are attached to a panel; 
         FIG. 10  is a sectional view of the state where a plug connector is inserted into the retaining clip of  FIG. 9 ; 
         FIG. 11  is a perspective view of the state after the retaining clip of  FIG. 2  and the receptacle connector are attached to the panel and before the plug connector is inserted into the retaining clip; and 
         FIG. 12  is an exploded perspective view of the retaining clip of  FIG. 2 , the receptacle connector, a shield cover, a gasket, and the panel. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 2–4  the retaining clip  10  comprises a base  11  having an opening or aperture  12  shaped to receive the free end of an electrical connector. The base  11  is intended to contact at least a portion of the outer surface of the casing for an electronic device such as a computer which the base overlies, and to ground the clip with respect to the casing. Hence, where the panel of the casing is planar the base is similarly planar. Engagement means in the form of a pair of locking tabs  13 ,  14 , that are preferably integral with the base  11 , partially project across one end of the aperture  12 . The locking tabs  13 ,  14  are shaped to engage detents provided on conventional electrical connectors. Engagement of the locking tabs  13 ,  14  with the detents on the electrical connector is by means of a sideways movement of the retaining clip  10  with respect to the electrical connector. 
     Extending upwardly from the base  11  are a plurality of resilient fingers  15  which form the walls of a cage shaped to receive the free end of a conventional electrical connector. Each finger  15 , which is separated from its neighbor by a narrow slot  16 , consists of first and second portions  17 ,  18 . The first portion  17  extends substantially perpendicular to the base  11  whereas the second portion  18  describes an arc which, in a direction from the first portion  17  to its free end, firstly curves into the region above the aperture  12  and then away from that region. Thus, the curved surface of each arc portion  18  acts as a contacting surface to the free end of the electrical connector. The fingers  15  extend along both long sides of the clip and across each end of the clip. Inclusion of fingers at the short ends of the retaining clip is deemed optional. 
     Each of the fingers  15  is movable so as to allow passage of the electrical connector whilst also forming contact with the surface of the connector. Preferably the fingers are biased towards the volume immediately above the aperture  12  but are sufficiently resilient that on contacting the electrical connector, the individual fingers are capable of outward flexure to permit the passage of the connector. As a result of the arc portion  18  of each finger, though, the fingers retain contact with the electrical connector as it is inserted through the aperture  12  and are capable of maintaining contact even over the surface of an irregularly shaped connector once the connector is locked in position. The width of each finger  15  and its length are selected in dependent upon the contact force to be applied by the finger to the electrical connector. The fingers  15  of the retaining clip  10  act to ground the electrical connector across a wide area and, as the base  11  is on contact with the casing to the electronic device, the retaining clip acts to ground the electrical connector with respect to the casing. Thus, the fingers  15  function as em shielding to prevent the escape of electromagnetic radiation from the electronic device of which the electrical connector forms a part and to shield against external electromagnetic radiation. 
     The performance of two retaining clips  10  in providing em shielding has been tested using a standard emc chamber and the following are results that were obtained. 
     
       
         
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Margin with respect to Class A (dB) for selected frequencies (MHz) 
               
               
                 Peak measurements in bold, quasi-peak measurements in brackets 
               
             
          
           
               
                 
                   Retaining 
                 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 
                   clip 
                 
                 
                   656 
                 
                 
                   700 
                 
                 
                   756 
                 
                 
                   984 
                 
                 
                   1310 
                 
                 
                   1970 
                 
                 
                   2620 
                 
                 
                   3280 
                 
                 
                   3610 
                 
                 
                   4590 
                 
               
               
                   
               
               
                 Testcase 
                 17 
                 20 
                 17 
                 14(11) 
                 23 
                 9 
                 13 
                 12 
                 12 
                 13 
               
               
                 1 
               
               
                 Testcase 
                 17 
                 13(10) 
                 10(6) 
                 14(10) 
                 15 
                 7 
                 10 
                  9.5 
                  9.5 
                  9.5 
               
               
                 2 
               
               
                   
               
             
          
         
       
     
     In  FIGS. 5–7  an alternative version of the retaining clip is illustrated. This alternative version of the retaining clip is very similar to the retaining clip of  FIGS. 2–4  and like reference numerals have been primed to indicate like features. The main difference between the two versions of the retaining clip is the inclusion of a plurality of slots  19 ′ cut into the base  11 ′ each of which extends into the first portion  17 ′ of a respective one of the resilient fingers  15 ′. These slots interrupt what is a continuous base in the first version of the retaining clip  10 . Thus, in this alternative version, the base  11 ′ comprises a plurality of separate segments surrounding the aperture  12 ′ with the fingers  15 ′ acting as bridging elements to hold the separate segments of the base  11 ′ together. 
     For both versions of the retaining clip described above, the clip  10  is preferably fabricated from a single metallic sheet that is cut by punching using a press and folded into the desired shape. This simplicity of construction greatly contributes to minimising the costs of fabrication. 
     Referring to  FIGS. 8 to 10 , a further alternative version of the retaining clip will be described. The further alternative version of the retaining clip is similar to the retaining clip of  FIGS. 2–4  and like reference numerals have been primed to indicate like features. The difference between the two versions will be described hereinafter. 
     In the first embodiment, each finger  15  is separated from its neighbor by a narrow slot  16 . On the other hand, each of resiliently deformable flat plates  15 ″ extending from opposite short sides of a base  11 ″ in this version has no slot, as shown in  FIG. 8 . Therefore, each flat plate  15 ″ is less resilient than each finger  15  in the first embodiment and is not easily deformable as compared with each finger  15  in the first embodiment. 
     Mechanical relationship among a retaining clip  10 ″, a plug connector  21 , and a panel  31  in this version will be described with reference to  FIGS. 9 and 10 . 
     The retaining clip  10 ″ is fitted into an aperture  32  of the panel  31  as shown in  FIG. 9 . In  FIG. 9 , the plug connector  21  is not yet inserted into the retaining clip  10 ″. 
     In  FIG. 10 , the plug connector  21  is inserted into the retaining clip  10 ″. 
     In this state, the plug connector  21  applies forces F 1 , F 2  to each flat plate  15 ″ in the direction of arrows, respectively. Then, forces F 3 , F 4 , F 5 , F 6  are produced at four points A, B, C, D of the retaining clip  10 ″ in the direction of arrows, respectively. F 3 , F 4  are forces exerted by the retaining clip  10 ″ to push the panel  31 . F 5 , F 6  are forces exerted by the retaining clip  10 ″ to push the plug connector  21 . Under the forces F 1 , F 2 , F 3 , F 4 , F 5 , and F 6 , the plug connector  21 , the retaining clip  10 ″, the panel  31 , and a receptacle connector  41  are electrically connected and grounded. 
     Referring to  FIGS. 11 and 12 , the structure of fitting the retaining clip  10  will be described in detail. 
     In  FIG. 12 , a shield cover  42  is attached to the receptacle connector  41  from the upper surface of the receptacle connector  41 . A gasket  43  is fitted to the receptacle connector  41  from the front surface of the receptacle connector  41 . Thereafter, the receptacle connector  41  is inserted into the aperture  32  of the panel  31  from the rear surface of the panel  31  and the retaining clip  10  is inserted into the aperture  32  from the front surface of the panel  31 . In the state shown in  FIG. 11 , the plug connector  21  is inserted into the retaining clip  10 . 
     The retaining clips in accordance with the invention thus provide both a locking mechanism for holding an electrical connector in place when inserted through an aperture in the casing of an electronic device such as a computer and also provides em shielding by grounding a wide surface area of the electrical connector to the outer surface of the casing. 
     Changes to the retaining clips described above are envisaged without departing from the present invention which is limited in scope by the accompanying claims only.