Abstract:
A plug connector includes a housing, a through-opening for a cable, and a seal adapted to seal in the area of the through-opening. A pressure plate is provided for compressing the seal between the pressure plate and a mating face in the housing, wherby part of the seal is pressed inwards in radial direction with respect to the through-opening.

Description:
TECHNICAL FIELD 
   The invention relates to a plug connector comprising a housing, a through-opening for a cable, and a seal adapted to seal in the area of the through-opening. 
   BACKGROUND OF THE INVENTION 
   The seal has the function to seal the cable at its passage into the interior of the housing, so that the ingress of humidity and dirt into the housing is prevented. A variety of constructions is known from prior art in the context of sealing around a cable. 
   It is the object of the invention to provide a plug connector including a seal which seals particularly well in the area of the cable passage and also allows to integrate several cables in one cable sealing. 
   SUMMARY OF THE INVENTION 
   According to the invention plug connector includes a housing, a through-opening for a cable, and a seal adapted to seal off in the area of the through-opening. A pressure plate is provided by means of which the seal can be compressed between the pressure plate and a mating face in the housing. Thereby part of the seal is pressed inwards in radial direction with respect to the through-opening In such arrangement the pressure plate fulfils two functions. On the one hand it urges the seal firmly against the housing, in order to ensure the sealing between the seal and the housing. On the other hand the pressure plate causes the seal being deformed due to which the seal rests firmly against the cable and establishes a good sealing effect at this place. 
   It is preferred that a compression face is provided by means of which the seal is urged radially inwards in the area of the through-opening. Such compression face can be arranged on the pressure plate and/or on the housing, in particular in the area of the through-opening for the cable, so that the seal can be effectively and directly pressed against the cable. Here it is of particular advantage if the compression face is constituted by a conical constriction in the area of the through-opening and the seal has a cylindrical projection which is compressed radially inwards at least in the area of its free end by the compression face. A wedging effect is produced in this way, by means of which a movement of the pressure plate in axial direction with respect to the through-opening brings about a deformation and displacement of the cylindrical projection of the seal in radial direction. This makes it possible to uniformly urge the seal radially inwards with a good mechanical efficiency, so that it rests tightly against the cable. 
   Screws can be used for fastening the pressure plate to the housing, so that in actual practice the pressure plate can be screwed in on the spot with low expenditure. The screws are preferably arranged such that the seal is uniformly compressed between the pressure plate and the housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows in a perspective exploded view a plug connector according to the invention; 
       FIG. 2  shows on an enlarged scale that area of the plug connector which has the through-openings for the cable; and 
       FIG. 3  shows in a perspective, partially sectional view that end of the plug connector which is provided with the through-openings, with the seal installed. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows a plug connector  1  including a first plug module  2  and a second plug module  3  which are arranged on opposite sides of a dividing wall  4 . Each plug module  2 ,  3  has a band clamp  5  associated to it, in which an outlined cable  8  is clamped, the conductors of which can be guided to the corresponding plug module  2 ,  3 . Each band clamp  5  serves both for relieving strain and making contact with a shielding surrounding the cable. 
   The plug modules  2 ,  3  are arranged on opposite sides of the dividing wall  4  in the interior of a housing  10 . The dividing wall  4  and the housing  10  either consist of metal or of metallized plastics; in this way a shielding against electromagnetic interference is obtained, and due to the dividing wall  4  a high stereo separation between the two plug modules  2 ,  3 . 
   In the embodiment which is shown in the Figures, the housing  10  has a rectangular cross-section and an end wall  12  on the side facing away from the plug modules  2 ,  3 ; formed in this end wall are a first through-opening  14  for a cable to be connected with the first plug module  2  as well as a second through-opening  16  for a cable to be connected with the second plug module  3 . The end wall  12  is arranged so as to be slightly set back, so that a surrounding skirt  18  is formed which projects from the end wall  12 . A stopping face  13  is provided on the end wall. 
   In the space enclosed by the skirt  18  there is arranged a seal  20  having a first through-opening  22  and a second through-opening  24 . The two seal through-openings  22 ,  24  are coaxial with the two housing through-openings  14 ,  16 . The seal  20  is made from an elastomer, in particular from soft rubber. 
   At the side of the seal  20  facing away from the end wall  12  there is arranged a pressure plate  26  which likewise is situated in the space enclosed by the skirt  18 . The pressure plate  26  is made from plastics or metal and has a first through-opening  28  and a second through-opening  30 . The first pressure plate through-opening  28  is coaxially aligned with the first seal through-opening  22  and the first housing through-opening  14 . The second pressure plate through-opening  30  is coaxially aligned with the second seal through-opening  24  and the second housing through-opening  16 . For fastening the pressure plate  26  to the housing  10  there are provided two screws  32  which are screwed into two threaded openings  34  in the end wall  12 . 
   The housing through-openings  14 ,  16  are each formed within a cylindrical projection  36  (see in particular  FIG. 3 ), which extends from the end wall  12  into the interior of the housing  10 . On its half facing the interior of the housing  10 , the cylindrical projection  36  is provided with a conical constriction  38  delimited by a compression face  40  towards the through-opening  14 ,  16 . Thus, the compression face  40  has a shape that is complementary with a truncated cone. 
   Around each of the through-openings  22 ,  24  the seal  20  has a cylindrical projection  42 , with one projection  42  being provided on each side of the body of the seal  20 . In other words, the seal  20  has a structure which is mirror-inverted with respect to a plane identical with the center plane of the body of the seal  20  and perpendicular to the axes of the two through-openings  22 ,  24 . The outer diameter of the cylindrical projections  42  of the seal  20  corresponds approximately to the maximum diameter of the housing through-openings  14 ,  16 . 
   The pressure plate  26  likewise is provided with a cylindrical projection  44  around its through-openings  28 ,  30 . Just like the projections  36  in the end wall  12  of the housing  10 , each pressure plate projection  44  is provided with a conical constriction  46  which is delimited on its inside by a compression face  48 . 
   The maximum diameter of the housing through-openings  14 ,  16  as well as of the pressure plate through-openings  28 ,  30  is approximately identical with the diameter of the cylindrical projections  42  of the seal  20 . The minimum diameter of the housing through-openings  14 ,  16  as well as of the pressure plate through-openings  28 ,  30 , i.e. the smallest diameter in the area of the constrictions  38 ,  46 , however, is smaller than the outer diameter of the seal projections  42 . 
   During assembly of the plug connector the cables to be connected are usually first pushed through the through-openings in the pressure plate  26 , the through-openings in the seal  20  and the through-openings  14 ,  16  in the end wall  12  of the housing  10  and connected with the two plug modules  2 ,  3  which are mounted in dedicated support means at both sides of the dividing wall  4 . Subsequently the two plug modules  2 ,  3  including the dividing wall  4  are pushed into the housing  10 . 
   The through-openings for the cables are sealed by arranging the seal  20  in the space enclosed by the skirt  18  and placing the pressure plate  26  on the seal. Then the pressure plate  26  is urged against the end wall  12  by means of the screws  32 , whereby the seal  20  is compressed between the pressure plate  26  and the end wall  12  acting as a mating face. In the process, the cylindrical projections  42  of the seal  20  are pushed into the conical constrictions  38 ,  46  in the end wall  12  of housing  10  and pressure plate  26 , respectively, whereby the seal is compressed radially inwards in this area. In  FIG. 3  there are to be seen two compressed portions  50  of the seal  20 , which are formed on the entry and exit ends of the seal through-opening. In this area the seal  20  firmly rests against the respective cable, so that a reliable sealing with a high IP protection class is achieved. The seal projection  42  also serves with its double-sided compressed portions  50  as a cable protection sleeve. 
   The pressure plate  26  provides for a uniform acting upon the seal  20 , so that a uniform and with this a very good sealing is achieved. Due to the advantageous arrangement of the two screws  32  lying diagonally opposite each other, only very few screws are required to make a uniform connection between the pressure plate  26  and the end wall  12  of the housing. An excessive compression of the seal is prevented by the stopping face  13  at which the pressure plate  26  can come to rest and which ensures a minimum distance of the pressure plate from the end wall. It is particularly emphasized that it would be possible to seal off several cables in the area of exiting from the housing.