Abstract:
There is disclosed a cable connector including a housing of an electrically insulating material containing one or more contact elements, one or more openings for accommodating a corresponding number of cables, and a means for establishing a connection to a counterpart, such as a header soldered to a printed circuit board. The means comprises a resilient latch which in turn comprises a guide with which the latch is fitted, preferably by means of sliding, into or onto a complementary guide, such as a groove or rail, on the housing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to a cable connector comprising a housing of an electrically insulating material containing one or more contact elements, one or more openings for accommodating a corresponding number of cables and a means for establishing a connection to a counterpart, such as a header soldered to a printed circuit board (PCB). 
     2. Description of Prior Development 
     Cable connectors of this kind are know, for instance from European patent application EP 0 801 446. This patent publication concerns a connector of the shielded type comprising a socket attached to a PCB and a plug designed to be mechanically and electrically coupled to the socket. One wall of the socket is covered with a shielding of electrically conducted material. This shielding is extended on its front part by projections folded back on themselves so as to form a spring, these springs emerging inside the socket and exerting a pushing force on the plug along a direction orthogonal to the direction of insertion of the plug into the socket, so as to establish a galvanic contact with the shielding of the plug. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a cable connector, especially a high speed cable connector, that is modular in nature and allows relatively uncomplicated assembly. 
     To this end, the cable connector according to the first paragraph is characterised in that the means for establishing a connection to a counterpart comprise a resilient latch which in turn comprises a guide with which the latch is fitted, preferably by means of sliding, into or onto a complimentary guide, such as a groove or rail, on the housing. 
     It is preferred that the cable connector comprises a stack of at least two of the said housings with the guide or the latch being fitted at least into or onto complimentary guides on the outermost housings. 
     The cable connectors according to the present invention can be assembled more easily using one or more modules. 
     The cable connector preferably comprises at least one coding pin which is sandwiched between the resilient latch and the housing. It is further preferred that the said housing comprises at least one cavity in which the coding pin is or can be placed, the cavity and one end or a section of the coding pin having corresponding cross-sections which enable placement of the pin in the cavity in one of a number of different positions. In this respect it is preferred that a top view of the other end of the coding pin is different for each of the said positions. As will be explained below, the said cavities and coding pin(s) provide(s) a large number of permutations and combinations for coding the cable connector and hence avoiding inadvertently misplacing a cable connector e.g. in a header where it does not belong. 
     The invention further pertains to a kit comprising contact elements, housings of an electrically insulating material containing one or more cavities for accommodating a corresponding number of contact elements and one or more openings for accommodating a corresponding number of cables, wherein the kit further comprises a resilient latch which in turn comprises a guide with which the latch can be fitted, preferably by means of sliding, into or onto a complementary guide(s), such as a groove or rail, on the housing or on the outermost housings of a stack of housings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further explained with reference to the drawings in which a preferred modular high speed cable connector in accordance with the present invention is schematically shown. 
     FIG. 1 is an exploded view of a cable connector comprising a single connector module. 
     FIG. 2 shows a cross-section through an assembled connector module similar to that of FIG.  1 . 
     FIG. 3 shows a substrate provided with a header for receiving one or more cable connectors. 
     FIG. 4 shows an assembled cable connector comprising a single connector module as well as a cable connector comprising two connector modules. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a cable connector module according to the present invention comprising a housing  1  of an electrically insulating material, such a polyamide or a liquid crystalline polymer. The housing  1  comprises, at least in this specific example, five cavities  2  for accommodating receptacle terminals  3  and two cavities  4  for accommodating ground contacts  5 . The cavities  2 ,  4  are associated with openings  6  in the front side of the housing  1  for receiving electrical connector pins which are part of a header (such as for instance shown in FIG.  3 ). The housing  1  further comprises openings  7  in its rear side for accommodating cables  8 . The shown cables  8  each comprise a differential pair  9 , a ground  10 , which are both fitted in a aluminium foil  11 , which serves as a shielding against electromagnetic interference (EMI), and an outer jacket (not shown). The differential pairs  9  and the grounds  10  are, upon assembly of the cable connector, attached to the respective contact elements  3 ,  5 . The cable connector module further comprises a cover  12  which can be snap-fitted into the upper side of the housing  1  by means of resilient diverging legs  13  as shown in FIG.  2 . FIG. 2 further shows that the entire cable connector module comprises a, partly embedded, metal shielding  14 ,  14 ′. 
     A pair of parallel guide grooves  15  is provided on either side of the housing  1  (parallel to the insertion direction of the cable connector) for receiving twin guide rails  16  which are part of a latch  17 . The latch  17  is made of a resilient metal and further comprises a V-shaped bent portion  18  for establishing a passive snap-fit connection with a complementary notch or groove on a header, as will be discussed below. The latches  17  can be securely attached to the housing  1  simply by sliding the guides  16  into the grooves  15  until the said guides  16  abut a stop  19  on the housing  1 . 
     The housing  1  further comprises two cavities  20  consisting of a cylindrical hole  21  and a semi-polygonal, in this case a semi-hexagonal, groove  21 ′ for receiving a coding pin  22  sandwiched between the latches  17  and the housing  1 . The coding pin  22  comprises a cylindrical end  23  which fits into the cylindrical hole  21 , an intermediate section  24  having a hexagonal cross-section which can be placed in six different positions in the groove  21 ′ and a semi-hexagonal end  25  for co-operation with a counter coding means associated with a header. The cavities  20  are rotated with respect to each other over an angle of 30°. 
     FIG. 3 shows a header which is part of a back plane  26  and which, again in this particular example, comprises an array of e.g. 6×7 pins  27 . A U-shaped shroud  28  comprising a base plate  29  and two parallel wall  30  is placed over and attached to the pins  27 . Each of these walls  30  is provided with a V-groove  31  on its outer surface which runs substantially parallel to the back plane  26  and which is complementary to the bent portion  18  of the latches  17  and allows passive (dis)connection of a cable connector comprising one or more connector modules and two latches  17 ,  17 ′ as shown in FIG.  4 . 
     Cavities consisting of a cylindrical hole, an open polygonal section  32  and a semi-polygonal groove  33 , are provided in the inner surface of the walls  30  on either side of each of the six rows of pins  27 . The cavities runs substantially perpendicular to the back plane  26  and may contain a counter coding pin  34 . The counter coding pin  34  comprises a cylindrical end  35 , which can be placed into the cylindrical hole, and a semi-hexagonal end  36 , which can be placed in six different positions in the open polygonal section  32  of the cavities in the shroud  28 . The semi-hexagonal end  36  of the counter coding pin  34  is complementary to the semi-hexagonal end  25  of the coding pin  22  and together they have a hexagonal cross-section that corresponds to that of open polygonal section  32  and to that of the intermediate section  24  of the coding pin  22 . 
     FIG. 4 shows a cable connector comprising two end-to-end stackable connector modules which are provided with alignment protrusions  37  and corresponding notches (on their lower surface; not shown) which are joined together by means of two latches  17 ′, one on each side of the cable connector. The twin guides  16 ′ of these latches  17 ′ are spaced apart by a distance which in this case roughly equals twice the height of the each of the connector modules or, in more general terms, the total height of all the connector modules comprised in the cable connector. Thus, the latches according to the present invention serve both as a means for establishing a connection with a connector counterpart and as a means for efficiently building different cable connectors from basic building blocks, such as the above-mentioned connector modules. 
     The coding pins according to a preferred embodiment of the present invention provide a stable guiding means for the cable connector during insertion into a counterpart, a coding means for avoiding mix-ups resulting in the connection of a cable connector to wrong counterpart positions, and a polarising means for avoiding upside down connections. Also, the number of coding options is very large, even with a small number of coding pins. Two of the above-described coding pins  22  in a cable connector comprising a single connector provide (in combination with counter coding pins  34 ) up to 36 coding options, whereas four coding pins  22 , e.g. in a cable connector comprising two connector joined together by means of the latches described above, provide 1296 coding positions. Polarisation is guaranteed if at least one of the coding pins  22  is rotated with respect to the other coding pins and, in that case, all the mentioned coding options can be used. 
     Within the framework of the present invention, the term “polygonal” means as a polygon, preferably a regular polygon, with at least five straight or substantially straight sides and angles. Semi-polygons are preferred, since they enable a large number of permutations of the coding pins and provide ample guidance and mechanical strength. 
     As a matter of course, the present invention is not limited to the above described preferred embodiment and can be varied in a number of ways within the scope of the claims.