Patent Publication Number: US-7914309-B2

Title: Electrical connector comprising a mat seal and a ramp system for compressing the mat seal

Description:
FIELD OF THE INVENTION 
     The present invention relates to electrical connectors with a mat seal. 
     EP-A1-1 296 415 describes an electrical connector of the type comprising:
         an insulative housing having:
           a front face for being mated with a counterpart electrical connector, and   a rear face for inserting cable terminals,   a plurality of terminal accommodating chambers, which each open on the rear face for inserting of a respective cable terminal, and on the front face so that the respective cable terminal accommodated in the accommodating chamber can be connected to a counterpart terminal of the counterpart connector,   a rear skirt extending rearward with respect to the rear face,   
           a mat seal disposed in the rear skirt against the rear face, and having a plurality of cable passages facing the accommodating chambers,   a rear grid, disposed in the rear skirt, against the mat seal, and having a plurality of cable passages facing the cable passages of the mat seal.       

     In the known electrical connector, the insulative housing comprises a housing body and a contact carrier, able to slide on each other. 
     For assembling the known electrical connector, cables are introduced through the mat seal for accommodating the terminals in the accommodating chambers arranged in the contact carrier. The known electrical connector comprises rotatory lever system for locking the connector to a counterpart connector. The lever system is arranged so that, when activated, it brings the housing body closer to the contact carrier. The housing body thus drags along the rear grid so that the rear grid compresses the mat seal. 
     This longitudinal compression leads to a shrinking of the cable passages of the mat seal, so that efficient sealing with the cables are obtained. 
     SUMMARY OF THE INVENTION 
     The invention proposes an electrical connector arranged so that an alternative assembling is possible. 
     Accordingly, the invention relates to an electrical connector of the previous type, comprising:
         a mobile part,   a guide rail fixed to the housing, the guide rail being transverse to the front-rear direction, for transversally guiding the mobile part,   a ramp system such that, when the mobile part is guided by the guide rail, the ramp system pushes the rear grid against the mat seal so as to compress the mat seal.       

     In the electrical connector of the invention, the mounting of the mobile part automatically leads to the compressing of the mat seal. In this way, the sealing of the cables occurs when the connector is assembled. 
     Other embodiments of the invention correspond to the features of claims  2  to  7  considered either separately or in combination. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood by reading the following description of a non limitative exemplary embodiment, referring to the drawings in which: 
         FIG. 1  is tri-dimensional view of an electrical connector according to the invention, before being assembled. 
         FIG. 2  is a tri-dimensional cross-sectional view along the II plane of  FIG. 1 , before the electrical connector is assembled. 
         FIGS. 3 and 4  are cross-sectional views along the III, IV plane of  FIG. 1 , the electrical connector being assembled. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Turning to the figures, an electrical connector  10  according to the invention is depicted. 
     The electrical connector  10  is a male connector of a type used in automotive applications, intended to mate with a counterpart female connector. In an alternative embodiment, the electrical connector according to the invention could be a female connector intended to mate with a counterpart male connector. 
     For the sake of clarity, the figures are orientated according to an XX′ axis, which stands for the mating direction. Every direction- or orientation related term in the following description, in particular the terms “rear” and “front”, refer to the XX′ axis. 
     The electrical connector  10  comprises an insulative housing  12 , usually made of a plastic material. The insulative housing  12  is essentially constituted of a parallelepiped having a front face  14  for being mated with a counterpart female electrical connector (not shown), and a rear face  16  (visible on  FIGS. 2 ,  3  and  4 ) for inserting cable terminals (not shown). 
     A plurality of accommodating chambers  18  are formed in the insulative housing  12 . Each accommodating chamber  18  opens, first on the rear face  16  for inserting a respective cable terminal, and second on the front face  14  so that the respective cable terminal accommodated in the accommodating chamber  18  can be connected to a counterpart terminal (not shown), of the counterpart connector. 
     A rear skirt  20  extends rearward with respect to the rear face  16 . Preferably, the rear skirt  20  is made integral with the housing  12 , in a single molding process. The rear skirt  20  defines a substantially rectangular rear aperture  22 , located opposite the insulative housing  12 . The rear skirt  20  is provided with two ribs  24 , located at two opposite sides of the rear aperture  22 . 
     The ribs  24  extend transversally relative to the XX′ direction. Each rib  24  forms a guide rail for a rear cap  26 . The ribs  24  project perpendicularly to the XX′ axis, i.e. toward the sides of the electrical connector, so as to form a stop for the rear cap  26  in the XX′ direction. 
     The rear skirt  20  is also provided with complementary ribs  25  which also extend transversally relative to the XX′ direction, but project along the XX′ direction, toward the rear face  16  of the connector, so that the complementary ribs  25  form a lateral stop for the rear cap  26 , preventing lateral displacement of the rear cap  26 . 
     The ribs  24  and the complementary ribs  25  are alternatively discontinuous. They complement each other, i.e. the discontinuity of the rib  24  corresponds to the presence of the rib  25 . This permits their molding. 
     The rear cap  26  is intended to be mounted on the rear skirt  20  so as to cover the rear aperture  22 . The rear cap  26  comprises two lateral walls  26 A provided with respective grooves  27  able to cooperate with the ribs  24  of the rear skirt  20 . The rear cap  26  is opened on a side between the lateral walls  26 A, so as to define a lateral cable entrance  28 . 
     Turning to  FIGS. 2 ,  3  and  4 , a mat seal  30 , made of elastomer material, is disposed in the rear skirt  20 , against the rear face  16 . The mat seal  30  is provided with a plurality of cable passages  32  facing the accommodating chambers  18 . 
     As can be seen on  FIG. 3 , a clearance is provided laterally between the mat seal  30  and the rear skirt  20 . In the depicted example, the clearance between the rear skirt  20  and the mat seal  30  is from 0.15 to 0.4 millimeters. The clearance insures that no compression is induced on the mat seal  30  by the rear skirt  20 . In this way, the cables may be inserted through the mat seal without deteriorating the mat seal  30 , since the mat seal is not compressed. In other words, the clearance that is present when the mat seal is not compressed, allows the enlargement of the passages of the mat seal, when the cables are introduced. 
     A rear grid  34  is also disposed in the rear skirt  20 , against the mat seal  30 . The rear grid  34  is provided with a plurality of cable passages  36  facing the cable passages of the mat seal  30 . 
     The rear grid  34  is able to slide along the XX′ axis in the rear skirt  20 , so as to move forward towards the insulative housing, and in particular towards the rear face  16 . 
     Once the electrical connector  10  is assembled, each cable thus makes a bend inside the rear cap  26 , before passing through the rear grid  34  then the mat seal  30 , in order to reach an accommodating chamber  18 , in which the terminal of the cable lies. 
     Turning in particular to  FIG. 4 , the rear grid  34  comprises two opposite peripheral latches  36 . Each latch  36  is intended to be received in a corresponding recess  38  arranged on the inner side  20 A of the rear skirt  20 . 
     In this way, the recesses  38  form a stop for maintaining the rear grid  34  in a pre-locking position against the mat seal  30 , via their cooperation with the latches  36 . The pre-locking position is depicted on  FIGS. 1 and 2 . More precisely, the recesses  38  and the latches  36  prevent the rear grid  34  from moving rearward in the rear skirt  20 , away from the rear face  20 . 
     The recesses  38  are placed in the XX′ direction so that the rear grid  34  in the pre-locking position does not compress the mat seal  30 . The cable passages  32  of the mat seal  30  are thus radially uncompressed, which allow an easy insertion/removing of the cables. Furthermore, the easy insertion/removing prevents deterioration of the mat seal. 
     The rear grid  34  further comprises two opposite rear flanges  40 . Each flange  40  projects rearward with respect to the rear grid  34 , along the inner side  20 A of the rear skirt  20 . The flanges  40  are chamfered at each of their ends, so as to form ramps  42 , see  FIGS. 1 and 2 . The flanges  40  are thus symmetrical. 
     The flanges  40  are preferably made integral and moulded in a single process with the rear grid. The flanges  40  are thus fixed to the rear grid. 
     The lateral walls  26 A are provided with inner ribs  44  projecting towards the inside of the rear cap  26 . 
     When the rear cap  26  is moved perpendicularly to XX′ guided by the ribs  24 , the inner ribs  44  hit the ramps  42 , which causes the rear grid  34  to slide along the XX′ direction, toward the mat seal in the rear skirt  20 , thus longitudinally compressing the mat seal  20  against the rear face  16  of the insulative housing  12  until an end position is attained. Since the flanges  30  are symmetrical, the rear cap  26  can be mounted from each extremity of the flanges. 
     Alternatively, the two flanges  40  can be replaced by a similar but unique flange projecting rearward from a medium line of the rear grid  24  situated between two rows of cable passages and the ribs  44  being replaced by a unique rib projecting toward the grid from a top of the cover  24 . 
     Since the ramps  42  are carried by the rear flanges  40 , a great distance between the rear grid  34  and the rear cap  26  is obtained. This great distance permits an easy bending of the cables. The cables are thus less likely to deteriorate. For this purpose, the height of the flange  40  can be between 3 to 10 mm, preferentially between 4 to 5 mm. 
     Once the end position is attained, the rear cap is locked by using clipping means, such as latches provided on the rear cap, so as to enter corresponding holes provided in the housing  12 . 
     Turning to  FIGS. 3 and 4 , showing the end position, the compression is maintained while the rear cap  26  covers the rear aperture  22  by the lateral walls  26 A of the rear cap  26  forming a stop for the flanges  40 , preventing a rear ward sliding of the rear grid  34 . 
     In the end position, the compression of the mat seal  20  along the XX′ direction leads to a radial shrinking of its passages  32 , which guarantees the sealing of the cables passing trough the seal  30 . 
     More particularly, the mat seal is laterally confined by the rear skirt  20 , so that the mat seal first extend against the rear skirt, i.e. until the clearance is filled up, then the passages shrink. 
     The assembling of the connector  10  is easy, because the mounting of the rear cap  26  automatically induces the sealing of the cables pressing through the mat seal  20 . 
     Similarly, if one needs to remove the cables, the disassembling of the rear cap  26  will let the rear grid  24  free of moving rearward, thus allowing a spring back of the mat seal  20 . In this way, the cables may be removed without deteriorating the mat seal  20 , which then can be re-used. 
     It should be noted that, since it is almost impossible to remove the cables without first disassembling the rear cap  26 , there is no risk that one would try to remove the cables with the mat seal in a compressed state. 
     The invention is not limited by the previous described example. For instance, the electrical connector could only have one flange. In another embodiment, the flanges could be carried by the rear cap, and/or have different form. 
     Furthermore, the guide rails could be formed by grooves instead of ribs. In that case, the lateral walls of the rear cap would be provided with corresponding ribs.