Patent Publication Number: US-7901239-B2

Title: Cable connector

Description:
The invention relates to a cable connector comprising a housing and ferrule receiving structures for receiving ferrule systems of at least two cables. 
     EP-A-1 122 834 discloses a cable connector comprising a housing with at least two cable exits and two locations for receiving a strain relief means. The receiving locations are staggered with respect to each other and are placed at an offset with respect to a center plane of the connector. 
     The trend in industries where cable connectors of the above-mentioned type are typically employed, such as telecom, is towards high density connection panels allowing high speed communication. The cable connector of the prior art is disadvantageous in that staggering and offsetting of the receiving locations results in increased dimensions for the cable connector, which is detrimental to the use in high density panels. 
     It is an object of the present invention to provide a cable connector for terminating at least two cables with reduced dimensions. 
     This object is achieved by a cable connector characterized in that each of said ferrule receiving structures is adapted to accommodate a flange of at least one of said ferrule systems and said ferrule receiving structures are arranged such that adjacent flanges of said ferrule systems substantially abut each other or at least partially overlap. The construction of the cable connector according to the invention makes the ferrule systems of the cables determine both the distance between adjacent cables and the electromagnetic shielding performance of the cable connector. Accordingly, such a cable connector can be optimized with respect to its dimensions and electromagnetic shielding performance by the shape and arrangement of the ferrule receiving structures. It is noted that in the case of abutment of adjacent flanges, a slit may still be present between the adjacent flanges. However, such a slit should according to the invention be negligible for electromagnetic shielding performance. The still allowable dimensions of the slit depend e.g. on the frequency of the signals transmitted through the cable. Finally, the flanges of the ferrule systems contribute to the strain relief performance of the cable connector. 
     In an embodiment of the invention, the housing comprises a first cover half and a second cover half, said first cover half and second cover half defining a split plane of said connector, each of said ferrule receiving structures being arranged substantially symmetrically with respect to said split plane. The prior art cable connector has an offset of the ferrule receiving structures with respect to the split plane of the connector. The absence of such an offset reduces the dimensions of the cable connector according to this embodiment of the invention. 
     In an embodiment of the invention, at least one the cable entries of the cable connector comprises one or more retention ribs. As the ferrule system of the cable is preferably applied over the shielding braid of the cable against the cable jacket and accordingly does not cover the cable jacket, this cable jacket might easily pop out of the cable entry when forces are exerted on the cable. The retention ribs in the cable entry prevent the cable jacket from popping out of the cable connector and avoid the need to attach the ferrule system to the cable near the section where the flange is provided. Further, the retention ribs enhance the cable bend relief performance of the cable connector. In a preferred embodiment of the invention, these retention ribs are chamfered with respect to the split plane of the cable connector. Consequently, closure of the cover halves to complete the cable entry results in a relaxation space for the cable jacket at the chamfered sections near the split plane preventing the cable jacket to get squeezed during closure. 
     In an embodiment of the invention, the ferrule receiving structures comprise a non-circular shaped section adapted to cooperate with a corresponding non-circular shaped part of said ferrule system. Such a construction results in an increased twist relief performance of the cable connector. 
     It should be noted that the above embodiments, or aspects thereof, can be combined. 
     The invention further relates to a cable connector assembly comprising a cable connector as described above and at least a first cable provided with a first ferrule system comprising a first flange and an adjacent second cable provided with a second ferrule system comprising a second flange, wherein said first and second ferrule system are adapted to receive a portion of, respectively, said adjacent second flange and said adjacent first flange. By structuring the ferrule systems such that they can accommodate a part of an adjacent flange, the cables are positioned closely together and appropriate electromagnetic shielding performance is maintained. Accordingly, the cable connector dimensions can be reduced. Preferably, each ferrule system comprises an inner ferrule and an outer ferrule arranged with respect to each other to determine a gap to receive said portion of said adjacent flange. 
     The invention also relates to a ferrule system for use in a cable connector or a cable connector assembly as described above, wherein said ferrule system comprises a flange and a structure to receive a flange of an adjacent ferrule system. Such a ferrule system allows for closely positioning of the cables in a cable connector and thus for a cable connector of reduced dimensions. In an embodiment of the invention, the ferrule system comprises an inner ferrule and an outer ferrule arranged with respect to each other to determine said structure to receive said adjacent flange. 
     In an embodiment of the invention, the ferrule system has an outer shape selected from the group comprising polygonal, hexagonal, square, elliptical, and D-shaped, which is advantageous for the twist relief performance of the cable connector assembly. 
     The invention will be further illustrated with reference to the attached drawings, which schematically show a preferred embodiment according to the invention. It will be understood that the invention is not in any way restricted to this specific and preferred embodiment. 
    
    
     
       In the drawings: 
         FIG. 1  shows a cable connector assembly according to an embodiment of the invention; 
         FIGS. 2A-2C  show a cable with a ferrule system according to an embodiment of the invention; 
         FIGS. 3A and 3B  show a cover half of the cable connector of the cable connector assembly shown in  FIG. 1  from different perspectives; 
         FIG. 4  shows a detailed image of a cable entry of the cable connector of  FIG. 3A ; 
         FIGS. 5A and 5B  shows the cable connector of  FIG. 3A  provided with the cable of  FIG. 2C ; 
         FIGS. 6A-6C  show schematic illustrations of different embodiments of flange arrangements, and 
         FIG. 7  shows a schematic illustration of an alternative configuration of cables with ferrule systems. 
     
    
    
       FIG. 1  shows a cable connector assembly  1  comprising a right-angled cable connector  2  and cables  3 A and  3 B. The cable connector  2  has a housing with cover halves  4 ,  5  mounted to each other by screws  6 . The cover halves  4  and  5  further each determine an external portion of a cable entry  7  at the back side of the cable connector that allows the cables  3 A,  3 B to enter the housing determined by the cover halves  4 ,  5 . 
     At the mating side of the cable connector  2  a shroud S protrudes from the housing. Terminal blocks  8  provide terminals for terminating wires (shown in  FIG. 5A ) of the cables  3 A and  3 B. The mating side also has mounting screws  9  to lock the cable connector  2  to a counterpart, such as a connector panel. 
       FIGS. 2A-2C  show a cable  10  with a ferrule system  15  according to an embodiment of the invention. The cable  10  comprises a cable jacket  12 , a shielding braid  13  and a plurality of wires  14  to be terminated at the terminal block housing  8  of the cable connector  2 . 
     In  FIGS. 2B and 2C , the cable  10  is provided with the ferrule system  15 . The ferrule system  15  comprises an inner ferrule  16  fitting around the shielding braid  13  of the cable  10 . The inner ferrule  16  is positioned against the cable jacket  12 . The shielding braid  13  is folded back over the inner ferrule  16  and then an outer ferrule  17  is positioned over the back folded part of the shielding braid  13 . The inner ferrule  16  and outer ferrule  17  are crimped in one operation with a hexagonal shaped tool with a predefined deformation zone, allowing deformation of material of the outer ferrule into predefined ears  18 .  FIG. 2C  shows the situation wherein the crimped outer ferrule  17  is removed from the cable  10  for clarity purposes. 
     The inner ferrule  16  further comprises a flange  19 . It should be appreciated that, although the flange  19  has a circular shape in the depicted embodiment, it may have non-circular shapes, such as hexagonal, square, elliptical, a D-shape etc. as well. 
     The inner ferrule  16  and outer ferrule  17  are arranged with respect to each other to determine a structure, displayed as a gap  20 , to receive a flange  19  of an adjacent ferrule system  15 . 
       FIGS. 3A and 3B  show the inner structure of the cover half  4  of the cable connector  2  depicted in  FIG. 1  from different perspectives. 
     The cover half  4  has a first ferrule receiving structure  30 A for the ferrule system  15 A of the cable  3 A and a second ferrule receiving structure  30 B for the ferrule system  15 B of the cable  3 B. The ferrule receiving structures  30 A and  30 B are located at the back side of the cable connector  2  just behind the cable entries  7 A and  7 B. The ferrule receiving structures  30 A and  30 B are arranged symmetrically with respect to an imaginary split plane defined by the separation plane of the cover halves  4  and  5 , i.e. the ferrule receiving structure  30 A formed in the cover half  4  is substantially identical to the ferrule receiving structure  30 A formed in the cover half  5 . The split plane is illustrated schematically in  FIG. 4 . 
     The ferrule receiving structures  30 A and  30 B comprise recesses  31 A and  31 B to accommodate the flanges  19 A and  19 B of the ferrule systems  15 A and  15 B. As most clearly shown in  FIG. 3B , the ferrule receiving structures  30 A and  30 B are arranged such that adjacent flanges  19 A and  19 B of the ferrule systems  30 A or  30 B at least partially overlap. This is illustrated in  FIGS. 5A and 5B . 
     Further, the ferrule receiving structures  30 A and  30 B comprise a structure  32 A and  32 B adapted to cooperate with the ears  18 A respectively  18 B of the ferrule systems  15 A and  15 B. The cooperation of these elements contributes to the twist relief performance of the cable connector assembly  1 . The ferrule receiving structures  30 A and  30 B also comprise positioning surfaces  33 A,  33 B adapted to accommodate the external structure of the outer ferrule  17 A,  17 B of the ferrule system  15 A,  15 B. It should be appreciated that the shape of the ferrule receiving structures  30 A,  30 B should be tuned to the external shape and dimensions of the ferrule systems  15 A,  15 B, including the flanges  19 A,  19 B. Preferably, the ferrule receiving structures  30 A and  30 B comprise a polygon shaped section adapted to cooperate with a corresponding polygon shaped part of the ferrule system  15 A,  15 B. The polygon shape is advantageous for the twist relief performance of the cable connector assembly  1 . 
     Finally, the cover half  4  has an internal space  34  for the wires  14  of the cables  3 A and  3 B and threaded holes  35  to receive the screws  6  for mounting the top cover half  5  to the cover half  4 . 
     The cable entries  7 A and  7 B for the cables  3 A and  3 B are provided with retention ribs  40 . These retention ribs  40 , albeit in a larger number, are also shown in the detailed image of the cable entry  7 A displayed in  FIG. 4 . The retention ribs  40  provide a saw tooth profile in the cable entry  7 A for interaction with the cable jacket  12  of the cable  3 A. As the ferrule system  15 A of the cable  3 A is applied over the shielding braid  13  of the cable  3 A and positioned against the cable jacket  12 , the ferrule system  15 A is not crimped on the cable jacket  12 . The retention ribs  40  prevent the cable jacket  12  from popping out of the cable connector entry  7 A when forces are exerted on the cable  3 A. These forces make the cable jacket  12  dig into the space between the retention ribs  40 . Further, the retention ribs  40  enhance the cable bend relief performance of the cable connector  2 . A similar profile may be present for the cable entry  7 B. 
     The cover halves  4  and  5  of the cable connector housing define an imaginary split plane, schematically illustrated by the line S in  FIG. 4 . The retention ribs  40  are chamfered with respect to this split plane by an angle α. The angle α preferably is 45°. Consequently, closure of the cover halves  4  and  5  to complete the cable entry  7 A results in a relaxation space for the cable jacket  12  at the chamfered sections near the split plane S preventing the cable jacket  12  to get squeezed during completion of the cable connector assembly  1 . 
       FIGS. 5A and 5B  depict the cable connector assembly  1  with cables  3 A,  3 B provided with ferrule systems  15 A,  15 B as shown in  FIG. 2B  mounted in the cable connector  2 . Identical reference numbers have been used to indicate identical parts of the cable connector assembly  1 . Clearly portions of the flanges  19 A and  19 B overlap with portions of the adjacent flange  19 B respectively  19 A. Consequently, when the cable connector assembly  1  is completed by mounting the top cover half  5 , a fully closed cable connector  2  is obtained with reduced dimensions and appropriate electromagnetic shielding performance. No additional parts are employed to obtain the closed cable connector  2  near the back side of the cable connector  2 . 
     The internal structure of the cable connector cover halves  4 ,  5  allows the ferrule systems  15 A and  15 B to be arranged such that the flanges  19 A,  19 B overlap. The ferrule systems  15 A,  15 B are shaped such that they can accommodate a part of an adjacent flange  19 B,  19 A. In  FIGS. 5A and 5B , this effect is facilitated by the provision the gap  20  between the inner ferrule  16 A,  16 B and the outer ferrule  17 A,  17 B for the flanges  19 A and  19 B. Accordingly, the respective flanges  19 A,  19 B have a slightly staggered arrangement. 
     The flanges  19 A and  19 B are positioned in the recesses  31 A and  31 B, enhancing the strain relief performance of the cable connector assembly  1 . 
     Further, the ear sections  18 A and  18 B, obtained by hexagonal crimping of the inner ferrules  16 A and  16 B and the outer ferrules  17 A and  17 B on the respective cables  3 A and  3 B, are positioned in the structures  32 A and  32 B of the ferrule receiving portions  30 A and  30 B. Consequently, the twist relief performance of the cable connector assembly is enhanced. 
     It should be noted that the wires  14  of the cables  3 A and  3 B are typically connected to terminals of the terminal blocks  8  before insertion in shroud S and mounting the top cover half  5 . 
     It should be noted that the above-described embodiment for the cable connector  2 , the cable connector assembly  1  and the ferrule system  15  does not limit the invention; further modifications are contemplated, such as providing the ferrule systems  15 A and  15 B with non-circular flanges  19 A,  19 B as depicted in  FIGS. 6A-6C . In  FIG. 6A  the flanges  19 A and  19 B have a hexagonal outer shape and overlap by staggering these flanges, as indicated by the dashed lines. In  FIG. 6B  an elliptical shape is shown for the flanges  19 A,  19 B, again in an overlapping arrangement.  FIG. 6C  shows a configuration with D-shaped flanges  19 A and  19 B that ideally abut each other at their flat sides, such that the cables  3 A and  3 B may contact each other, resulting in a further reduction of the dimensions of the cable connector  2 . This configuration, however, may in practice yield a negligibly small slit d between the flanges  19 A and  19 D. Such a small slit d however is not detrimental for the electromagnetic shielding performance of the cable connector assembly  1 . Other shapes for the flanges  19 A,  19 B, either abutting each other (with a possible small slit d) or overlapping each other fall under the scope of the present invention as well. The dimensions of the flanges may vary. 
     Further, the retention ribs  40  may have any shape or profile, such as staggered and/or intermittent ribs in the first cover half  4  and second cover half  5 , as long as the function of cooperating with the cable jacket  12  can be fulfilled. 
     Also, the deformation sections  18 A,  18 B on the outer ferrule  17 A,  17 B can have other shapes. 
     Furthermore, the cable connector  2  may be suited for more than two cables  3 A,  3 B with the ferrule receiving structures  30  appropriately shaped and arranged to fulfill the purpose of the invention. 
     Although preferably, the ferrule systems  15 A,  15 B are identical in shape, the advantage of the invention can also be obtained by ferrule systems of different shape. Accordingly, the invention also relates to a cable connector  2  comprising a housing and at least a first ferrule receiving structure  30 A for receiving a first ferrule system  15 A with a flange  19 A of a first cable  3 A and a second ferrule receiving structure  30 B for receiving a second ferrule system  15 B of a second cable  3 B, wherein said first receiving structure  30 A and second receiving structure  30 B are adapted to accommodate said flange  19 A and said flange  19 A is adapted to cooperate with said second ferrule system to close said cable connector  2  near a cable entry  7 A,  7 B. Such a configuration is schematically illustrated in  FIG. 7 .