Abstract:
A connector includes an insert including contacts having free parts to receive homologous flat contacts of a plug. The insert further includes a rotation axis about which the insert can be rotated and spring means urging the insert toward the position that it assumes when no plug is present. The insert can include, at the sides, long curved contacts and, in a central portion, shorter curved contacts, the points of contact of the contacts of the insert with the flat contacts of a plug being substantially aligned over all the contacts.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention concerns a computer network connector. It applies in particular to RJ45 connectors used for computer networks and covered by the IEC standard 11 801. 
     2. Description of the Prior Art 
     RJ45 connectors must be able to accept all RJ45 plugs and sometimes standard RJ11 type plugs without damaging the contacts. Because the tolerances on the dimensions of these plugs are relatively wide, the contacts of the insert of the RJ45 connector must be flexible to accept plugs representing the extremes. However, these contacts must also be sufficiently rigid to provide the necessary contact pressure between the contacts of the insert and the flat contacts of the plugs to obtain a contact of good quality reflected in a low contact resistance. 
     A number of solutions to this problem are known. A first produces relatively long insert contacts that incorporate crossovers between some contacts to prevent increasing crosstalk problems and to make a start on compensating them. The limitations of this solution are that the compensation achieved between the crossover and the printed circuit (if the insert is pushed onto or soldered to a circuit) is not of optimum efficacy because compensation is effected in air, which entails conforming to standard isolation distances. 
     A second solution uses shorter contacts to be pushed onto or soldered to a circuit as close as possible to the point of contact to benefit rapidly, in terms of the phase shift of the signal, from the compensation opportunities that the printed circuit provides. In this case, the material used to produce the contacts of the insert is more costly, for example beryllium bronze. 
     Another solution uses a flexible circuit coming into contact with (or soldered to) the metal contacts of the insert as close as possible to the point of contact and incorporating appropriate compensation means. The drawbacks of this solution are in particular the cost of the flexible circuit and production engineering problems linked to the flexible circuit. 
     SUMMARY OF THE INVENTION 
     The present invention aims to overcome these drawbacks. 
     To this end, the present invention concerns a connector including an insert including contacts having free parts to receive homologous flat contacts of a plug, a rotation axis about which said insert can be rotated and spring means urging the insert toward the position that it assumes when no plug is present. 
     Thanks to these features, when inserting a plug having the largest dimensions authorized by the standard, the insert rotates and the free parts of the contacts are not permanently deformed. Moreover, despite this flexibility, the contact pressure remains high and guarantees a contact of good quality and, in particular, a low contact resistance. 
     According to particular features, said insert includes, at the sides, long curved contacts and, in a central portion, shorter curved contacts, the points of contact of the contacts of the insert with the flat contacts of a plug being substantially aligned over all the contacts. 
     Thanks to these features, the contacts have different stiffnesses and allow the insertion of plugs that do not include flat contacts corresponding to the contacts of the central part, for example RJ11 plugs, and plugs including as many flat contacts as there are contacts in the insert, for example RJ45 plugs. The longer free parts of the lateral contacts allow greater elastic deformation. 
     According to particular features, the outermost contacts form two pairs and have a crossover for compensating crosstalk. 
     According to particular features, said insert includes partially overmolded or crimped contacts. Thanks to these features, the relative contact positions are fixed by the overmolding or the crimping, and crosstalk compensation crossovers, capacitances and/or inductances can be formed inside the overmolding or the crimping. 
     According to particular features, contact crossovers and capacitive lands are provided inside the overmolding to compensate crosstalk generated by the plug. 
     Thanks to these features, crosstalk is compensated near the points of contact, which improves its efficacy. Moreover, when the insert rotates, the crossovers and capacitive lands are protected from the risk of deformation and therefore of contact with the overmolding or the crimping. 
     According to particular features, the spring means includes a leaf spring positioned behind the rotation axis relative to the direction of plugging in the plug. 
     The leaf spring is therefore positioned to the rear of the insert to ensure sufficient contact pressure and to return the insert to its original position on unplugging the plug. This leaf spring can be either an attached metal component or part of a plastic component of the connector, for example. The shape, length, section and material of this leaf spring can be defined without having to comply with constraints imposed by any standards, in contrast to the contacts of the insert. 
     According to particular features, the insert includes at least one protuberance forming an abutment on which at least one contact comes to bear when plugging in a plug having the maximum dimensions of a standard covering said plug. 
     For example, for a plug with dimensions greater than those of the mini plug, the contacts come to bear on at least one protuberance of the overmolded part and the insert turns about its rotation axis. This prevents the risk of its contacts being permanently deformed on inserting a maxi plug. In the event of permanent deformation, the contact pressure between the insert and a mini plug could be insufficient to guarantee a contact with the flat contacts of the mini plug of good quality, or could even produce no contact at all. 
     According to particular features, contacts have a portion to the rear of the rotation axis relative to the direction of plugging in the plug and bearing on lands of a printed circuit. 
     According to particular features, contacts have a portion to the rear of the rotation axis relative to the direction of plugging in the plug and bearing on metal blades from which are formed insulation-displacement contacts used for connections at the rear of the connector. 
     According to particular features, contacts have a portion to the rear of the rotation axis relative to the direction of plugging in the plug and in contact with conductive strips linked to insulation-displacement contacts. 
     Thanks to each of these features, the free movement of these three portions towards the rear when the insert rotates is reflected in sliding of the area of contact and therefore avoids the risk of forces that could lead to breakage or fatigue, such as could appear in the case of soldering instead of bearing interengagement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages, objects and features of the present invention will emerge from the following description, given by way of nonlimiting explanation and with reference to the appended drawings, in which: 
         FIG. 1A to 1C  represent, in three different directions, one particular embodiment of an insert forming part of a connector of the present invention, 
         FIG. 1D  represents the insert shown in  FIGS. 1A to 1C  without the overmolding defining the body of the insert, 
         FIGS. 2A and 2B  represent, in two different directions, respectively as seen from the rear connection side and from the plug insertion side, one particular embodiment of a connector of the present invention incorporating the insert shown in  FIG. 1A to 1D , 
         FIG. 3  represents the connector shown in  FIGS. 2A and 2B  associated with a crosstalk compensation printed circuit, 
         FIG. 4  represents in cross section the connector and the printed circuit from  FIG. 3  when a plug with the minimum dimensions is inserted into the connector, 
         FIG. 5  represents the same view as  FIG. 4  when a plug with the maximum dimensions is inserted into the connector, 
         FIGS. 6 to 8  represent an associated insulation displacement contact terminal block in a second embodiment of a connector of the present invention, and 
         FIG. 9  represents in cross section a variant of the connector shown in  FIGS. 4 and 5 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As explained above, the present invention applies in particular to RJ45 connectors with eight contacts used for computer networks and governed by IEC standard 11 801. The description given hereinafter concerns this type of connector. However, the present invention is not limited to this type of connector and, to the contrary, extends to all connectors having contacts and intended to receive a plug having homologous flat contacts. The RJ45 connectors represented in the figures are intended to receive RJ45 plugs and must be able to accept RJ11 plugs with four contacts defined by the standard without damaging the contacts. The tolerances on the dimensions of these plugs being relatively wide, the contacts of the insert of the connector are sufficiently flexible to accept the extreme plugs and sufficiently rigid to ensure a sufficient contact pressure between the contacts of the insert and the flat contacts of the plugs needed for a contact of good quality that is reflected in a low contact resistance. 
     The free parts of the contacts of the insert that come into contact with the flat contacts of the plug are substantially coplanar. For the requirements of the description, the contacts of the insert are numbered from  11  to  18  in their order in the rear portion starting from one of the lateral contacts. Thus an RJ11 plug has flat contacts that come to bear on the contacts  13  to  16  whereas an RJ45 plug has flat contacts that come to bear on the contacts  11  to  18 . 
     According to the present invention, and as seen in  FIGS. 1A to 2A ,  6  and  7 , an insert  110  of a connector  105  has a rotation axis  115  substantially parallel to the plane corresponding to the coplanar portions of the free parts of the contacts that receive in bearing interengagement the flat contacts  155 A or  155 B (see  FIG. 4  or  5 ) of a plug (not shown). This rotation means that shorter contacts can be used than in the prior art in the portion intended to come into contact with the flat contacts of the plug, in order to reduce the distance between that portion and the crosstalk compensation capacitors, whilst being able to receive plugs at the standardized tolerance limits, as explained with reference to  FIGS. 4 and 5 . The reduction of the length of the front portions of the contacts necessary for compensating crosstalk between signals of very high frequency would not allow sufficient travel of the limit plugs. 
     The shortest contacts are those that correspond only to RJ45 plugs. The lateral contacts, which correspond to RJ11 plugs, are subjected to higher mechanical stresses because they must be able to deform upon insertion of an RJ45 plug. To the extent that their electrical constraints in terms of crosstalk are more limited, the front portions of these lateral contacts are preferably the same size as in the prior art. 
     In the embodiment described and shown, the insert  110  includes contacts  11  to  18  over a central portion of which an insert body  120  is molded. Alternatively, a crimping technique (not shown) is used instead of overmolding. 
     As can be seen in  FIG. 2A , the insert  110  is “clipped” by “clip” means  185  in the connector  105 , which is a molded component. 
     As seen in the figures, the contacts  11  to  18  do not have identical free parts. The contacts  13  to  16  have a shorter free part than the contacts  11 ,  12 ,  17  and  18 . The most severe crosstalk problems are formed for the signals carried by the contact pairs  13 - 16  and  14 - 15 , and the free parts of the contacts  13  to  16  being shorter, the signals that they convey are subjected to less phase shift at their entry into the overmolded part  120 . At least one crossover  125 B and capacitive lands  130 A to  130 F are provided inside this overmolded part  120  to compensate crosstalk caused by the plug. 
     Thus the free parts of the contacts  11  to  18 , receive in bearing interengagement the flat contacts of the plug corresponding to the contacts  12 ,  11 ,  13 ,  15 ,  14 ,  16 ,  18  and  17 , in that order. 
     The length, section and material of the free part of the contacts  13  to  16  are preferably such that these contacts accept the deformation generated by the introduction of a plug with the minimum dimensions authorized by the standard (referred to hereinafter as a “mini” plug, as compared to a “maxi” plug that corresponds to the maximum dimensions authorized by the standard) and such that these contacts  13  to  16  guarantee a contact pressure of 100 grams per contact. 
     As shown in  FIGS. 2A ,  4 ,  5  and  7 , a leaf spring  140  bears on the body  120  of the insert  110  on the side of the body  120  opposite the side in which the areas of contact on the contacts  11  to  18  are situated. 
     As shown in  FIG. 4 , for a mini plug, the leaf spring  140 , being sufficiently rigid, is not deformed and holds the insert  110  in position to guarantee a good contact pressure between the flat contacts  155 A of the plug and the contacts of the insert. 
     As shown in  FIG. 5 , for a plug with dimensions greater than those of the mini plug, the contacts  13  to  16  come to bear on at least one protuberance  135  of the overmolded part  120  provided for this purpose to prevent permanent deformation of the contacts  13  to  16 , and the insert  110  turns around its rotation axis  115 . 
     The leaf spring  140  is deformed slightly whilst providing the necessary contact pressure between the flat contacts  155 B of the plug and the contacts of the insert. The elasticity of the leaf spring  140  allows the insert  110  to return to its original position on unplugging the plug. 
     This avoids the risk of permanent deformation of the contacts  13  to  16  on inserting a maxi plug. In the event of permanent deformation, there would be a risk of the contact pressure between the insert  110  and a mini plug being insufficient to guarantee a good quality of contact with the flat contacts  155 A of the mini plug, or even providing no contact at all. 
     Note also that the longer free parts of the contacts  11 ,  12 ,  17  and  18  allow greater deformation and the protuberances  135  do not face these contacts, which allows the insertion of an RJ11 plug that causes large but not permanent deformation of these contacts. The crosstalk constraints of the contact pairs  1112  and  17 - 18  being less severe than those of the contact pairs  11 - 15  and  14 - 16 , these contacts are longer to be able to withstand the insertion of RJ11 plugs. A crossover  125 A, respectively  125 C, is provided after the first bend in the contacts  11  and  12 , respectively  17  and  18 , starting from the area of contact with the flat contacts of the plug, to commence crosstalk compensation as soon as possible. In the embodiment described and shown, the crossovers  125 A and  125 C are outside the overmolding  120 . To avoid accidental contact, each crossover has a separation film  126 , for example a film of adhesive polyamide. A capacitive land  130 A is formed by enlarging the contact  12  toward the contact  11  inside the overmolding  120 . A capacitive land  130 F is formed by enlarging the contact  17  toward the contact  18  inside the overmolding  120 . 
     Inside the body of the insert, i.e. the overmolding  120 , a crossover  125 B is provided between the contacts  14  and  15 . A capacitive land  130 C is formed by facing planes formed in the contacts  13  and  15 . A capacitive land  130 D is formed by facing planes formed in the contacts  14  and  16 . These planes are separated by a film  145 A, respectively  145 B, for example a film of adhesive polyamide. 
     Note that the capacitive lands  130 C and  130 D are as close as possible to the front parts of the contacts  13  to  16 . Because of this, and because the front parts of the contacts  13  to  16  are shortened, crosstalk compensation is effected very close to the area of contact of the homologous flat contacts of the plug. This compensation is therefore effected with a very limited phase shift and therefore extends up to very high frequencies of the signals conveyed. 
     Note also that the films  145 A and  145 B project at the sides farther from the respective capacitive lands  130 C and  130 D than the film  126  of the crossover area of the contacts because breakdown problems are greater in air than inside the overmolding. 
     A capacitive land  130 B is formed by enlarging the contact  13  toward the contact  12  inside the overmolding  120 . A capacitive land  130 E is formed by enlarging the contact  16  toward the contact  17  inside the overmolding  120 . 
     In the embodiment shown in  FIGS. 1A to 5 , the leaf spring  140  positioned to the rear of the insert  110  is molded in one piece with the connector  105  to provide sufficient contact pressure and to return the insert to its original position on unplugging the plug. Note that the shape, length, section and material of this leaf spring  140  can be defined without having to comply with the constraints of any standards, in contrast to the contacts of the insert  110 . 
     To enable rotation of the insert  110 , the ends of the contacts outside the overmolding (on the rear side relative to the direction of plugging in the plug) are not inserted into a printed circuit  150  but press on SMC (Surface Mount Component) lands or patches of the printed circuit  150  (see  FIGS. 3 to 5 ), which provide electrical continuity. 
     Note that, because of the rotation of the insert when inserting a plug larger than a mini plug, the rear parts of the contacts press harder on a printed circuit  150  without exceeding their elastic limit, which avoids permanent deformation thereof. 
     In a second embodiment, shown in  FIGS. 6 to 8 , these rear free ends press directly on metal blades from which are formed insulation-displacement contacts (IDC) used for the connections at the rear of the RJ45 connector. 
     Alternatively, and in particular if the performance to be achieved does not require the use of a printed circuit to compensate crosstalk, for connectors of category 5, for example, the insert  110  comes directly into contact with strips  170  from which are formed the insulation-displacement contacts  175 , as shown in  FIGS. 6 to 8 . The insulation-displacement contacts can be produced from two cut and bent strips. 
       FIG. 6  shows that the insulation-displacement contacts  175  are formed from two cut and bent strips  170 . Note, in  FIG. 7 , that the areas of contact are pressed between the rear parts of the contacts of the insert  110  and the strips  170  of the insulation-displacement contacts  175 . Note, in  FIG. 8 , that the strips of insulation-displacement contacts  170  are mounted in and held in position in a plastic terminal block  165 . Note also that an abutment (not shown) is positioned under the contact area. 
     As can be seen in  FIG. 9 , in the second embodiment, the spring effect necessary for returning the insert to its original position is produced by the metal blade  195  mounted in the connector  180  and not by the molded connector as in the first embodiment. Thus the leaf spring  140  molded into the connector  105  of the first embodiment is replaced by a leaf spring  195  crimped into the connector  105 . This second embodiment can in particular be useful in the case of a shielded product where the connector would be of zamac and would not allow the necessary flexibility to be obtained. 
       FIG. 9  also shows the crimping of the circuit  150  to the connector  105  by means of crimped lugs  190 . This crimping circumvents stacking of the tolerances of all the parts and therefore reduces the relative movement of the contacts pressing on the circuit  150  between “mini clearance” and “maxi clearance” positions.