Abstract:
The invention relates to an electrical contact arrangement ( 1 ) for telecommunications and data systems technology, comprising at least one electrical contact (K 1 ) and a printed circuit board ( 2 ), the contact (K 1 ) being connected to the printed circuit board ( 2 ) both electrically and mechanically. The contact (K 1 ) comprises a contact region ( 7 ) on which an electrical contact for contacting the counter-contact is generated. The distance (L el) between the contact region ( 7 ) of the contact (K 1 , K 8 ) and the electrical contact point (K 8 ) for contacting the printed circuit board ( 2 ) is shorter than the distance (L mech) between the contact region ( 7 ) of the contact (K 1 , K 8 ) and the mechanical contact point ( 9 ) for contacting the printed circuit board ( 2 ).

Description:
This application is a National Stage Application of PCT/EP2007/010932, filed 13 Dec. 2007, which claims benefit of Serial No. 10 2007 002 768.2, filed 18 Jan. 2007 in Germany and which applications are incorporated herein by reference. To the 
     BACKGROUND 
     Such a contact arrangement is known, for example, by the RF contacts of an RJ45 socket. These RF contacts are mechanically and electrically connected to a printed circuit board. In this case, the RF contacts are sprung in order to produce a sufficiently effective electrical contact despite certain tolerances of the sockets and plugs. For reasons of electrical transmission properties, it is endeavored to select the contacts to be as short as possible. On the other hand, the contacts need to be sufficiently long such that they spring to a sufficient extent to compensate for tolerances and to produce sufficient contact force. 
     Against the background of this prior art, the invention is based on the technical problem of providing an electrical contact arrangement which has good electrical transmission properties and nevertheless is sufficiently sprung. 
     SUMMARY 
     In this regard, the electrical contact arrangement for telecommunications and data technology comprises at least one electrical contact and a printed circuit board, the contact being connected both electrically and mechanically to the printed circuit board, the contact having a contact region on which an electrical contact to a mating contact is produced, the length between the contact region of the contact and the electrical contact point with the printed circuit board being shorter than the length between the contact region of the contact and the mechanical contact point with the printed circuit board. As a result, decoupling between the electrical and the mechanical properties of the contact is achieved such that a sufficient spring effect can be set without the electrical transmission properties being substantially altered. The mechanical contact point is in this case achieved either by a fixed connection by means of adhesive bonding, soldering or the like or else by the contact being fixedly clamped against the printed circuit board. 
     Preferably, the contact between the electrical contact point and the mechanical contact point is bent back from the printed circuit board. 
     In a further preferred embodiment, in addition, a further electrical contact point to the printed circuit board is formed via the mechanical contact point. In addition to reasons of redundancy, this further contact point can be used for charging compensation capacitances. 
     In a further preferred embodiment, the electrical contact is pressed against the printed circuit board under prestress via a comb element. This ensures a sufficient contact force. 
     In a further preferred embodiment, the printed circuit board is mounted such that it can move in relation to a housing part via a spring-elastic element. This makes it possible for a further part of the required excursion to be distributed and for the mechanical length of the contact to be selected such that it is correspondingly shorter. The spring-elastic element is in this case preferably in the form of an elastomer, rubber element or in the form of a spring, preferably a metal spring. 
     In a further preferred embodiment, the printed circuit board is mounted fixedly in a second housing part, the second housing part being connected to the first housing part such that it can pivot. This prevents contacts, which are mounted, for example, in the second housing part and are connected via soldered joints to the printed circuit board, from being moved in relation to the printed circuit board as a result of the movement of the printed circuit board, which could otherwise result in the soldered joints being torn away. 
     In a further preferred embodiment, the second housing part is designed to have at least one receptacle for a cylinder of the first housing part, which receptacles then together form a pivot-bearing arrangement. 
     In a further preferred embodiment, the electrical contact arrangement is in the form of an RJ45 contact arrangement, at least the two outer contacts being designed to have a mechanical length which is longer than the electrical length. This results in the two outer contacts not being damaged in the case of an RJ11 plug inadvertently being plugged in, since the RJ11 plug does not have any contacts there, but lower-lying housing parts, such that, in the prior art, damage to the contacts often arises. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail below with reference to a preferred exemplary embodiment. In the figures: 
         FIG. 1  shows a cross-sectional illustration of an electrical contact arrangement, 
         FIG. 2  shows a perspective illustration of an RJ45 contact arrangement, and 
         FIG. 3  shows a side view of a first and second housing part. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an electrical contact arrangement  1  comprising at least one electrical contact K 1 , a printed circuit board  2 , a contact-pressure spring  3  having an intermediate piece  4  and a second housing part  6 . The electrical contact K 1  has a contact region  7 , an electrical contact point  8  with the printed circuit board  2  and a mechanical contact point  9  with the printed circuit board  2 . The printed circuit board  2  is mounted fixedly in the second housing part  6 . The printed circuit board  2  is mounted such that it can move in relation to a first housing part  5  (see  FIG. 3 ) and provided with a spring prestress via the contact-pressure spring  3 . The second housing part  6  is in this case designed to have a receptacle  11 , which accommodates a cylinder of the first housing part  5 . 
     At the mechanical contact point  9 , the contact K 1  is fixedly connected to the printed circuit board  2 , whereas, at the electrical contact point  8 , the contact K 1  is only pressed against the printed circuit board  2  in a sprung manner. The length L el between the contact region  7  of the contact K 1  and the electrical contact point  8  with the printed circuit board  2  is in this case shorter than the length L mech between the contact region  7  and the contact K 1  and the mechanical contact point  9  with the printed circuit board  2 . If a mating contact, for example in the form of a plug, is now inserted into the first housing part, it generally comes into contact with the contact region  7  of the contact K 1  and produces an electrical connection. Owing to the prestress of the electrical contact K 1  by a comb element (not illustrated) and the prestress of the printed circuit board  2  by the contact-pressure spring  3 , it is ensured here that the contact force between the mating contact and the contact region  7  is sufficiently great if the plug otherwise presses the contact K 1  only slightly downwards in the direction of the printed circuit board  2  owing to tolerances. If, however, owing to tolerances or an incorrect plug being incorrectly inserted, the contact K 1  is pressed by the plug to a considerable extent downwards in the direction of the printed circuit board  2 , this can firstly be compensated for by virtue of the fact that the printed circuit board  2  is pressed downwards counter to the contact-pressure spring  3  and, secondly, the contact K 1  absorbs this force by deforming the contact K 1  between the electrical contact point  8  and the mechanical contact point  9 . The contact-pressure spring  3  and the contact K 1  are in this case designed in terms of spring constants such that, at first, the excursion is primarily compensated for by the contact-pressure spring  3 . The electrical contact point  8  therefore remains largely uninfluenced and the tolerances of the plug can be compensated for without the quality of the contact to the printed circuit board  2  being influenced. However, if an incorrect plug has been inserted which for example, has a low-lying housing part instead of a mating contact, the contact K 1  absorbs this additional excursion by sprung deformation without being destroyed. This results in the electrical contact point  8  of the contact K 1  being pushed in the direction of the mechanical contact point  9 . In an extreme case, this may result in the electrical contact to the printed circuit board  2  being interrupted, which is not critical, however, since an incorrect plug in any case should not or does not need to come into electrical contact. Otherwise, this would be significant owing to a sufficiently large dimensioning of the contact pad on the printed circuit board  2 . Since the electrical transmission properties are largely determined by the electrical length L el, good electrical and mechanical properties are thus achieved at the same time. The part of the contact K 1  between the electrical contact point  8  and the mechanical contact point  9  can influence, if need be, the electrical transmission response by means of capacitive couplings. 
       FIG. 2  illustrates the electrical contact arrangement  1  for an RJ45 socket, this RJ45 socket having eight contacts K 1  to K 8 , which are in the form of RF contacts. In this case, the two outer contacts K 1  and K 8  are designed to have a longer mechanical length L mech since these two contacts K 1  and K 8  are at particular risk from an RJ11 plug. As can be seen from the figure, the capacitive coupling of the contact parts between the electrical contact point  8  and the mechanical contact point  9  to other contacts K 2  to K 7  is low. Furthermore, it can be seen that the contacts K 2  to K 7  are bent alternately in opposite directions to one another in order to minimize the crosstalk in the contact region  7 , since the capacitive coupling is low. 
     Eight insulation displacement contacts K 11  to K 18  are arranged on the opposite side of the printed circuit board  2  and are connected electrically to the contacts K 1  to K 8  via the printed circuit board  2 . The insulation displacement contacts K 11  to K 18  are in this case connected to the printed circuit board  2  via SMD-like contacts K 21  to K 28 . In this case, the connections between the contacts K 11 , K 12 , K 17  and K 18  and the contacts K 21 , K 22 , K 27  and K 28  is slightly longer than between the contacts K 13  to K 16  and K 23  to K 26 . This results in more pronounced capacitive coupling which is compensated for by the connections being crossed over. In this case, the insulation displacement contacts K 11 , K 12 , K 17 , K 18 , which belong to the outer contact pairs K 1 , K 2 , K 7 , K 8 , are preferably the longer contacts in comparison with the contacts K 13  to K 16 , since crosstalk between the outer contact pairs is generally less critical. In this case, express reference will once again be made to the fact that, for example, the contacts K 11 , K 21  and K 1  are electrically connected to one another. Likewise, the contacts K 12 , K 22  and K 2  etc., i.e. associated contacts, each have the same unit as the index. It can further be seen that the longitudinal direction of the insulation displacement contacts K 11  to K 18  is parallel to the SMD-like contacts K 21  to K 28  and the surface of the printed circuit board  2 . 
     It can be seen in  FIG. 3  how the first housing part  5  with a cylinder  10  engages in the receptacle  11  of the second housing part  6 , with the result that a pivot-bearing arrangement is formed such that the printed circuit board  2  can move in relation to the first housing part  5  and, on the other hand, is rigid with respect to the second housing part  6 . 
     LIST OF REFERENCE SYMBOLS 
     
         
           1  Contact arrangement 
           2  Printed circuit board 
           3  Contact-pressure spring 
           4  Intermediate piece 
           5  First housing part 
           6  Second housing part 
           7  Contact region 
           8  Electrical contact point 
           9  Mechanical contact point 
           10  Cylinder 
           11  Receptacle 
         K 1 -K 8  contacts 
         K 11 -K 18  Insulation displacement contacts 
         K 21 -K 28  SMD-like contacts 
         L el Electrical length 
         L mech Mechanical length