Patent Publication Number: US-9431729-B2

Title: Contact, connector and method for manufacturing connector

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-061634, filed on Mar. 19, 2012, the entire contents of which are incorporated herein by reference. 
     FIELD 
     A certain aspect of the embodiments discussed herein is related to a contact, a connector and a method for manufacturing a connector. 
     BACKGROUND 
     A coaxial cable is widely used as a connection for various electric circuits. In the coaxial cable, a central conductor (i.e., a core wire or a signal line) that conducts a signal, and an outer conductor (i.e., a braided shield part) to which a ground potential is given are provided concentrically. In Patent Document 1 (see Japanese Laid-Open Patent Application No. 2011-23319), the central conductor and the outer conductor are soldered to a tabular conductor provided on the surface of a substrate, so that the substrate is constituted as a harness. With respect to a connection method of the coaxial cable, a method for inserting the harness into a receptacle of a connector is disclosed in Patent Document 1. 
     A technique concerning a contact and a connector that are connectable to the coaxial cable is disclosed in Patent Document 2 (see Japanese Registered Utility Model No. 3069472) and Patent Document 3 (see Japanese Laid-Open Patent Application No. 10-223269) 
     SUMMARY 
     According to an aspect of the present invention, there is provided a contact including: a cable connection portion that is connected to a signal line in an exterior cable; a fixed portion that is extended toward a front edge of the contact from the cable connection portion, and fixed to an exterior connector cover; and a connector connection portion that is extended toward the front edge of the contact from the fixed portion, and connected to a conductor of an exterior connector. 
     The objects and advantages of the invention will be realized and attained by the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view of a connector according to a first embodiment; 
         FIG. 2  is a perspective view of a first contact; 
         FIG. 3  is a rear view of the first contact; 
         FIG. 4  is a perspective view of a second contact; 
         FIG. 5  is a rear view of the second contact; 
         FIG. 6  is a perspective view illustrating an assembling process (i.e., a first mounting process) of the connector according to the first embodiment; 
         FIG. 7  is a perspective view illustrating an assembling process (i.e., a removal process) of the connector according to the first embodiment; 
         FIG. 8  is a perspective view illustrating an assembling process (i.e., a second mounting process) of the connector according to the first embodiment; 
         FIG. 9  is a partial top view of the connector illustrated in  FIG. 8 ; 
         FIG. 10  is a perspective view illustrating a connection condition of the connector and the coaxial cable according to the first embodiment; 
         FIG. 11  is a perspective diagram of a connector according to a second embodiment in which assignment of the signals differs from assignment of the signals of  FIG. 10 ; 
         FIG. 12  is a perspective view of the connector according to the second embodiment; 
         FIG. 13  is a rear view of the connector according to the second embodiment; 
         FIG. 14  is a perspective view illustrating another example of the second contact; 
         FIG. 15  is a perspective view of the connector according to a third embodiment; 
         FIG. 16  is a perspective view illustrating a connection condition of the connector and twin-coaxial cables according to the third embodiment; 
         FIG. 17  is a perspective diagram of the connector according to the third embodiment in which assignment of the signals differs from assignment of the signals of  FIG. 16 ; 
         FIG. 18  is a perspective view of the connector according to a fourth embodiment; 
         FIG. 19  is a rear view of the connector according to the fourth embodiment; And 
         FIG. 20  is a perspective view of the connector according to a fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     (First Embodiment)  FIG. 1  is an exploded perspective view of a connector according to a first embodiment. The connector includes first contacts  1 , a second contact  2  and a connector cover  3 . Here, coaxial cables  4  to be connected to the connector are also illustrated in  FIG. 1 . 
     The connector of the present embodiment is connected to the two coaxial cables  4 . Each of the coaxial cables  4  includes a core wire  41  that is a central conductor, an insulator  40  that covers the periphery of the core wire  41 , and an outer peripheral shield part  42  that covers the periphery of the insulator  40  as an outer conductor. The core wire  41 , the insulator  40  and the outer peripheral shield part  42  are concentrically formed as viewed from a cross-section surface of the coaxial cable  4 . The core wire  41  functions as a signal line transmitting a signal. 
     In the coaxial cable  4 , a signal is transmitted to the core wire  41 , for example. On the contrary, a ground potential (GND) is given to the outer peripheral shield part  42 , and a characteristic impedance is set as 50 (Ω) or 75 (Ω). There is no limitation in the material and the size of the coaxial cable  4 . 
     The connector cover  3  is an insulating member for holding and covering the first contacts  1  and the second contact  2  as a housing, and is obtained by carrying out injection molding of an elastic plastic, for example. The connector cover  3  has a shape in which four cut edge parts  34   a  to  34   d  arranged in a width direction and through-holes  33   a  to  33   d  are provided on a rectangular parallelepiped indicated by a width W 1 ×a length L 1 ×a height H 1 . The cut edge parts  34   a  to  34   d  are spaces in the shape of the rectangular parallelepiped which exist between five wall parts  30  arranged in the width direction, respectively. The wall parts  30  are mutually opposed so as to be spaced by an interval d 1  in the width direction. 
     Each of the through-holes  33   a  to  33   d  is a rectangular parallelepiped-like space which is surrounded with a pair of the wall parts  30 , a top board part  31  and a bottom board part  32 , and the through-holes  33   a  to  33   d  are coupled to the cut edge parts  34   a  to  34   d , respectively. The top board part  31  and the bottom board part  32  are spaced by an interval h and are opposed to each other in a height direction. The through-holes  33   a  to  33   d  and the corresponding cut edge parts  34   a  to  34   d  are arranged so as to be spaced by a constant pitch. For example, the width W 1 , the length L 1 , the height H 1 , the interval d 1  and the interval h are 5.08 mm, 3mm, 1.27mm, 0.9 mm and 0.8 mm, respectively. 
     Each of the first contacts  1  and the second contact  2  is a member that electrically connects a connection object of the connector to the coaxial cable  4 , and is made of a conductive component, such as copper. The first contacts  1  are connected to the core wires  41  of the coaxial cables  4 , and are inserted into the through-holes  33   a  and  33   c  via the cut edge parts  34   a  and  34   c . The second contact  2  is connected to the outer peripheral shield part  42  of the coaxial cable  4 . The second contact  2  includes the two same members as the first contacts  1 , and the two members are inserted into the through-holes  33   b  and  33   d  via the cut edge parts  34   b  and  34   d.    
       FIG. 2  is a perspective view of the first contact  1 . The first contact  1  has a longitudinal shape of a length L 2 , and includes a cable connection part  10 , a fixed part  11  and a connector connection part  12 . The length L 2  is 3.5 mm, for example. In the following description, an end of the connector connection part  12  in a length direction is expressed as “a front edge”, and an end of the cable connection part  10  in the length direction is expressed as “a rear edge”. 
     The cable connection part  10  is connected to the core wire  41  which is a signal line of the coaxial cable  4 . The cable connection part  10  includes a bottom face  100 , and a pair of opposed side faces  101  standing from both ends of the bottom face  100 , for example. Then, the cable connection part  10  functions as a portion that accepts the core wire  41  of the coaxial cable  4 . The shape of the cable connection part  10  is not limited to this, and may be the shape of a tube or a flat plate. 
     When the first contact  1  is fixed to the connector cover  3 , the cable connection part  10  is held in a position protruded from the rear edge of the connector cover  3  so that soldering is easy. A distance d 3  between the side faces  101  and a height H 2  are decided according to the size of the core wire  41 , and are, for example, 0.5 mm and 0.8 mm, respectively. 
       FIG. 3  is a rear view of the first contact  1 . The bottom face  100  and the side faces  101  constitute a horseshoe shape, and have high adhesion with a surface of the core wire  41 . Furthermore, in order to improve adhesion, the bottom face  100  and the side faces  101  may have another shape, such as the shape of a semi-circle. Here, in order to align a front edge of the core wire  41 , a front edge side of the cable connection part  10  may be provided with an alignment, such as a convex part. 
     The fixed part  11  illustrated in  FIG. 2  is extended toward the front edge from the cable connection part  10 , and is fixed to the connector cover  3 . Since the fixed part  11  is press-fitted into the connector cover  3 , the fixed part  11  has an extended part  110  in which both sides of the bottom face  100  are extended in a width direction, and has the widest width W 2  (e.g. 0.97 mm) in the first contact  1 . At the time of the press-fit, the extended part  110  is pressed into each of the cut edge parts  34   a  to  34   d  of the connector cover  3  while pressing and extending both sides of the wall parts  30  in a width direction. Therefore, the connector cover  3  may be made of a material with flexibility. As long as the fixed part  11  is connectable to the connector cover  3 , the fixed part  11  may not be limited to the shape of a rectangular plate illustrated in  FIG. 2  and may have another shape. Although in the present embodiment, a press-fit system is explained as a fixed means, the fixed means is not limited to this but may be a fitting system, for example. 
     The connector connection part  12  is extended toward the front edge from the fixed part  11 , and is connected to a conductor of an exterior connector (i.e., the connection object). For example, the connector connection part  12  pinches an exterior convex conductor. When the connector is connected to a pin of the exterior connector which is the connection object, the connector connection part  12  pinches the connection object to secure electrical connection. 
     The connector connection part  12  is tabular clip members in which the front edges thereof spread outwardly, for example. The connector connection part  12  includes: a pair of base side walls  120  that are extended from both side ends of the bottom face  100  in the height direction; a pair of arm parts  121  that are extended toward the front edge from the pair of base side walls  120 ; and a pair of contact parts  122  are extended toward the front edge from the pair of arm parts  121 . When the pair of arm parts  121  and the pair of contact parts  122  are press-fitted into the connector cover  3 , they are held in each of through-holes  33   a  to  33   d.    
     The pair of arm parts  121  extend in the shape of straight lines toward the front edge and have a function of flat springs, so that the arm parts  121  are biased in a direction in which a distance between the arm parts  121  narrows. The pair of contact parts  122  contact the connection object of the connector. The arm parts  121  have arc shapes as viewed from above so that the front edges of the arm parts  121  spread outwardly. Projecting portions of the arcs are spaced by an interval d 2  and are opposed to each other. Therefore, the pin of the connection object can easily extend the pair of contact parts  122  outwardly and can contact the pair of contact parts  122 . On the contrary, the connector connection part  12  may have a pin shape, and the conductor of the exterior connector of the connection object may have a clip shape. Here, the distance d 2  is decided according to the size of the connection object, and is 0.1 mm, for example. 
     As described above, since the first contact  1  has the cable connection part  10  connected to the core wire  41  of the coaxial cable  4 , soldering with the core wire  41  is easy. Since the first contact  1  has the fixed part  11  to be fixed to the exterior connector cover  3 , the assembly work of the connector is simplified. Moreover, since the first contact  1  has the connector connection part  12  to be connected to the conductor of the exterior connector, the first contact  1  is connected to the pin which is the connection object of the connector, without using another connection member. 
     Then, in the first contact  1 , the cable connection part  10 , the fixed part  11  and the connector connection part  12  are extended according to this order, so that a conductive path from the conductor of the exterior connector as the connection object to the core wire  41  of the coaxial cable  4  is secured. Therefore, a characteristic impedance of a connection part between the first contact  1  and the coaxial cable  4  is easily matched with a characteristic impedance of a connection part between the first contact  1  and the conductor of the exterior connector, and the manufacture of the first contact  1  is easy. 
       FIG. 4  is a perspective view of a second contact  2 . The second contact  2  includes a plate-like shield connection part  20 , and main units  21   a  and  21   b . Each of the main units  21   a  and  21   b  is held in the connector cover  3 , and is the same as the above-mentioned first contact  1 . Each of the main units  21   a  and  21   b  is connected to the shield connection part  20  via a convex coupling part  210  extending toward a rear edge side from the above-mentioned bottom face  100 . 
     The shield connection part  20  is connected at the rear edge side of the cable connection part  10 , and contacts the outer peripheral shield part  42  of the coaxial cable  4 . The shield connection part  20  is formed in the shape of a board, and extends in a direction perpendicular to a direction in which the cable connection part  10 , the fixed part  11  and the connector connection part  12  are arranged. The present embodiment is not limited to a case where plural sets of cable connection parts  10 , fixed parts  11  and connector connection parts  12 , i.e., plural main units  21   a  and  21   b  are provided on the single shield connection part  20 , and a single main unit may be provided on the shield connection part  20 . The shield connection part  20  may be integrally molded with at least one main unit  21   a  or  21   b.    
       FIG. 5  is a rear view of the second contact  2 . The shield connection part  20  contacts the outer peripheral shield part  42  of the coaxial cable  4 , curves so as to draw the shape of a waveform in an extending direction, and accepts the outer peripheral shield part  42  along the curve at a position shifted from the cable connection part  10 . Specifically, a mountain part  201  and a valley part  200  that project upward and downward in the height direction, respectively, are alternately formed in the shield connection part  20 . The mountain part  201  of the shield connection part  20  is connected to the cable connection part  10 , and the valley part  200  of the shield connection part  20  accepts the outer peripheral shield part  42 . 
     In order to improve adhesion, the valley part  200  may be formed according to the shape of the outer periphery of the outer peripheral shield part  42 . A distance between the mountain part  201  and the valley part  200  may be decided according to a distance between adjacent through-holes ( 33   a  and  33   b ,  33   b  and  33   c , or  33   c  and  33   d ) or adjacent cut edge parts ( 34   a  and  34   b ,  34   b  and  34   c , or  34   c  and  34   d ) of the connector cover  3  so that the main units  21   a  and  21   b  of the second contact  2  are easily inserted into the connector cover  3 . 
     Since the second contact  2  includes the construction of the first contact  1 , the second contact  2  obtains the above-mentioned effects of the first contact  1 . Moreover, since the shield connection part  20  of the second contact  2  is a plate-like member, the manufacture of the second contact  2  is easy, as is the case with the first contact  1 . 
     Next, a description is given of a method for manufacturing the connector according to the present embodiment. In a first mounting process illustrated in  FIG. 6 , the second contact  2  is fixed to the connector cover  3  by the fixed parts  11  so that the connector connection parts  12  are held in the through-holes  33   a  and  33   c  arranged in the connector cover  3 . At this time, the fixed parts  11  extend the wall parts  30 , and are press-fitted into the cut edge parts  34   a  and  34   c . Thereby, the connector connection part  12  of the main unit  21   a  is held in the through-hole  33   a , and the connector connection part  12  of the main unit  21   b  is held in the through-hole  33   c  adjacent to the through-hole  33   b.    
     Next, in a removal process, the shield connection part  20  of the fixed second contact  2  is removed. In the removal process, the coupling parts  210  are cut off along a line C in  FIG. 6  with a cutter, such as a nipper, and the shield connection part  20  is separated from the main units  21   a  and  21   b  , for example. Thereby, the main units  21   a  and  21   b  are processed like the first contact  1 , as illustrated in  FIG. 7 . 
     Next, in a second mounting process illustrated in  FIG. 8 , another second contact  2  is fixed to the connector cover  3  by the fixed parts  11  so that the connector connection parts  12  are held in the through-holes  33   b  and  33   d  among the through-holes  33   a  to  33   d . Thereby, the connector connection part  12  of the main unit  21   a  is held in the through-hole  33   b , and the connector connection part  12  of the main unit  21   b  is held in the through-hole  33   d  adjacent to the through-hole  33   c.    
       FIG. 9  is a partial top view of the connector illustrated in  FIG. 8 . Rear edges of the cable connection parts  10  of the first contacts  1  are away from the shield connection part  20  of the second contact  2  by an interval d 4  so that the first contacts  1  in which the connector connection parts  12  are held in the through-holes  33   a  and  33   c  is electrically separated from the second contact  2  in which the connector connection parts  12  are held in the through-holes  33   b  and  33   d  . This is because the first contacts  1  to be connected to the core wires  41  of the coaxial cables  4  are insulated from the second contact  2  to be connected to the outer peripheral shield part  42 . The interval d 4  is 0.5 mm, for example. 
     The connector of the first embodiment is obtained by the processes described above. According to the manufacturing method, the connector can be assembled easily by the effects of the first contacts  1  and the second contact  2  described above. 
       FIG. 10  is a perspective view illustrating a connection condition of the connector and the coaxial cable  4  according to the first embodiment. The core wires  41  of the coaxial cables  4  are accepted by the cable connection parts  10  of the first contacts  1  and are soldered to the cable connection parts  10 . On the contrary, the outer peripheral shield parts  42  are accepted by the valley parts  200  of the shield connection part  20  of the second contact  2  and are soldered to the valley parts  200 . Therefore, the shield connection part  20  is connected to the rear edge side of the cable connection part  10  of one or more first contact  1  to be connected to a ground of the exterior connector. The positions in the width direction of the cable connection part  10  and the valley part  200  can be identical with each other by adjusting the distance between the adjacent through-holes ( 33   a  and  33   b ,  33   b  and  33   c , or  33   c  and  33   d ) or the distance between the mountain part  201  and the valley part  200 . Therefore, the cable connection part  10  and the valley part  200  are soldered simultaneously and easily. 
     In this connector, the first contacts  1  are fixed to the connector cover  3  by the fixed parts  11  so that the connector connection parts  12  are held in the through-holes  33   a  and  33   c  . On the contrary, the second contact  2  is fixed to the connector cover  3  by the fixed parts  11  so that the connector connection parts  12  are held in the through-holes  33   b  and  33   d  . The through-holes  33   a  and  33   c  for holding the connector connection parts  12  of the first contacts  1 , and the through-holes  33   b  and  33   d  for holding the connector connection parts  12  of the second contact  2  are adjacent to each other. That is, the first contact  1  to be connected to the ground of the exterior connector, and the first contact  1  to be connected to the signal line are adjacent to each other. 
     The connector of the first embodiment is obtained by the processes described above. According to the manufacturing method, the connector can be assembled easily by the effects of the first contacts  1  and the second contact  2  described above. 
     The connector is connected to coaxial cable  4 , so that a coaxial cable with the connector that alternately assigns a signal flowing through the core wire  41  and a ground potential of the outer peripheral shield part  42  to the through-holes  33   a  to  33   d  can be obtained. Thus, the signal and the ground potential are arranged so as to adjoin each other, so that an electrical characteristic is stabilized and impedance matching becomes easy. 
     (Second Embodiment)  FIG. 11  illustrates a connector in which assignment of the signal and the ground potential differs from assignment of the signal and the ground potential of  FIG. 10 . The through-holes  33   e  to  33   h  arranged in a line in  FIG. 11  correspond to the through-holes  33   a  to  33   d  in  FIG. 10 . In the through-holes  33   e  to  33   h  of the connector cover  3 , the through-holes  33   e  and  33   g  hold the connector connection parts  12  of the second contact  2 , and the through-holes  33   f  and  33   h  hold the connector connection parts  12  of the first contacts  1 . In this connector, the assignment of the signal and the ground potential is reversed, compared with the connector illustrated in  FIG. 10 . 
       FIG. 12  illustrates the connector of the second embodiment configured such that the connectors illustrated in  FIGS. 10 and 11  are stacked as stack members. With respect to the through-holes  33   a  to  33   h  arranged in two lines, codes “S” and “G” in  FIG. 12  indicate the assignment of the above-mentioned signal and the above-mentioned ground potential, respectively. In the connector, the signal and the ground potential are assigned to the through-holes  33   a  to  33   h  so as to be adjacent to each other in the width and the height directions. That is, in the contacts arranged in two lines, one contact  1  that is arranged in one line and connected to the ground of the exterior connector (i.e., connection object), and another contact  1  that is arranged in another line and connected to the signal line of the exterior connector are adjacent to each other. 
     The connector illustrated in  FIG. 10  and the connector illustrated in  FIG. 11  are mutually connected at the bottom board part  32  of the connector in  FIG. 10  and the top board part  31  of the connector in  FIG. 11 . Therefore, it is desirable that a concave part and a convex part are provided on the surfaces of the top board part  31  and the bottom board part  32 , and each of the concave part and the convex part serves as an alignment for mutually aligning the top board part  31  and the bottom board part  32  or a fitting for mutually fixing the top board part  31  and the bottom board part  32 . The connector illustrated in  FIG. 10  and the connector illustrated in  FIG. 11  may be pasted by an adherent such as adhesion materials without using the concave part and the convex part. 
       FIG. 13  is a rear view of the connector according to the second embodiment. In the two lines in which the through-holes  33   a  to  33   h  are arranged, the shield connection part  20  ( 20   a ) of the second contact  2  in which the connector connection parts  12  are held in the through-holes  33   b  and  33   d  of an upper line contacts along the curves the outer peripheral shield parts  42  accepted by the shield connection part  20  ( 20   b ) of the second contact  2  in which the connector connection parts  12  are held in the through-holes  33   e  and  33   g  of a lower line (see code “P” in  FIG. 13 ). That is, the mountain parts  201  of the upper connector contact the outer peripheral shield parts  42  of the coaxial cables  4  connected to the lower connector. That is to say, the shield connection part  20  ( 20   a ) that is connected to the contacts  2  arranged in one line, and the shield connection part  20  ( 20   b ) that is connected to the contacts  2  arranged in another line accept the outer peripheral shield parts  42  along the respective curves. 
     Therefore, it is desirable that each mountain part  201  of the shield connection part  20  is formed according to the shape of the surface of the outer peripheral shield part  42 , as is the case with the valley part  200 . Thus, by connecting more outer peripheral shield parts  42  to the shield connection part  20 , the ground potential is stabilized and the consistency of characteristic impedances improves. 
     (Third Embodiment) A third embodiment illustrates an example of a connector that is applied to a twin-coaxial cable as a substitute for the coaxial cable  4  described above.  FIG. 14  is a perspective view illustrating a second contact  5  used for the third embodiment. The second contact  5  includes a shield connection part  50  and three main units  51   a  to  51   c  . Each of three main units  51  a to  51  c is the same member as the first contact  1  illustrated in  FIG. 2 , and connected to the shield connection part  50 , as is the case with the previous embodiments. The shield connection part  50  is a plate-like member having a flat surface, unlike the previous embodiments. 
       FIG. 15  is a perspective view of the connector according to the third embodiment. The connector is obtained by a process for fixing the second contact  5  to a connector cover  6  by the fixed parts  11  and a process for removing the shield connection part  50  of press-fitted second contact  5 , as is the case with the manufacturing method of the above-mentioned connector. 
     In the connector cover  6 , the number of through-holes  61   a  to  61   g  is different from the number of through-holes of the previous embodiments. The through-holes  61   a  to  61   g  are arranged in a line. The connector connection parts  12  of the main units  51   a  to  51   c  of the second contact  5  are held in the through-holes  61   a ,  61   d  and  61   g , respectively. The connector connection parts  12  of the first contacts  1  obtained by the above-mentioned removal process are held in the through-holes  61   b ,  61   c ,  61   e  and  61   f.    
       FIG. 16  is a perspective view illustrating a connection condition of the connector and twin-coaxial cables  7  according to the third embodiment. The connector of the third embodiment is connected to two twin-coaxial cables  7 . Each of two twin-coaxial cables  7  includes: two core wires  71 ; two insulators  70  that are provided around the core wires  71  and adjacent to each other; a drain wire  73  adjacent to one insulator  70 ; and an outer peripheral shield part  74  that covers the peripheries of the insulators  70  and the drain wire  73 . Each of the core wires  71  functions as a signal line transmitting a signal. 
     The outer peripheral shield part  74  has a flat surface extending in the width direction, and is soldered to the shield connection part  50  via the flat surface. The core wires  71  are accepted by the cable connection parts  10  of the first contacts  1  in the through-holes  61   b ,  61   c ,  61   e  and  61   f , and soldered to the cable connection parts  10 . 
     On the contrary, the drain wires  73  are accepted by the cable connection parts  10  in the through-holes  61   a  and  61   d , and soldered to the cable connection parts  10 . Each of the core wires  71  and the drain wires  73  is bent to compensate a positional difference between each of the core wires  71  and the drain wires  73 , and each of corresponding cable connection parts  10 . Since the drain wire  73  contacts the outer peripheral shield part  74 , the drain wire  73  has the ground potential. 
     When it is assumed that each of the through-holes  61   b ,  61   c ,  61   e  and  61   f  that holds the connector connection part  12  of the first contact  1  is set as a first hole, and each of the through-holes  61   a ,  61   d  and  61   g  that holds the connector connection part  12  of the second contact  5  is set as a second hole, the through-holes  61   a  to  61   g  are arranged in order of the second hole, the first hole and the first hole. That is, in this connector, the assignment of terminals is performed based on a pattern of the ground potential, the signal, and the signal, as seen in the example of the codes “S” and “G” in  FIG. 16 . Thereby, the transmission of differential signals, such as LVDS (Low Voltage Differential Signaling), is realized. 
     (Fourth Embodiment)  FIG. 17  illustrates a connector in which the assignment of the signals and the ground potential differs from the assignment of the signals and ground potential of  FIG. 16 . Through-holes  61   h  to  61   n  arranged in a line in  FIG. 17  correspond to the through-holes  61   a  to  61   g  of  FIG. 16 . In the connector, the through-holes  61   i  and  61   i  of the connector cover  6  hold the connector connection parts  12  of the main units  51   d  and  51   e , respectively, of the second contact  5 , and the through-holes  61   h  ,  61   j  ,  61   k ,  61   m  and  61   n  of the connector cover  6  hold the connector connection parts  12  of the first contacts  1 . That is, the assignment of the signals and the ground potential in the connector is shifted by one terminal in the width direction, compared with the connector of  FIG. 16 . Here, since the twin- coaxial cable  7  is not connected to the through-hole  61   h  , a signal is not assigned to the connector connection part  12  in the through-hole  61   h  (see a code “N”). 
       FIG. 18  illustrates the connector of the fourth embodiment configured such that the connectors illustrated in  FIGS. 16 and 17  are stacked as stack members. A method for stacking the connectors as the stack members is the same as that of the second embodiment. With respect to the through-holes  61   a  to  61   n  arranged in two lines, the codes “S” and “G” in  FIG. 18  indicate the assignment of the above-mentioned signal and the above-mentioned ground potential, respectively. In the through-holes  61   a  to  61   n  of the connector arranged in two lines, the second hole, the first hole and the first hole arranged in one line are adjacent to the first hole, the second hole and the first hole arranged in another line, respectively. 
       FIG. 19  is a rear view of the connector according to the fourth embodiment. As is the case with the second embodiment, the shield connection part  50  of the second contact  5  of an upper line among the two lines in which the through-holes  61   a  to  61   n  are arranged contacts the outer peripheral shield parts  74  accepted by the shield connection part  50  of the second contact  5  of a lower line (see codes “Q” in  FIG. 19 ). Therefore, the same effects as those in the above described embodiments can be obtained. 
     (Fifth Embodiment)  FIG. 20  illustrates a connector configured such that an upper connector cover  8   a  having in-line through-holes  81   a  to  81   h  and a lower connector cover  8   b  having in-line through-holes  81   i  to  81   p  are stacked as stack members. In each of the upper connector cover  8 a and the lower connector cover  8 b, the first contacts  1  and the second contact  5  are press-fitted by the above-mentioned manufacturing method. Then, each of the shield connection parts  50  of the second contacts  5  is connected to the two twin-coaxial cables  7 . Here, the second contact  5  of the fifth embodiment includes four main units. A connection direction of the twin-coaxial cable  7  in the width direction is opposite to that of the twin-coaxial cable  7  of the fourth embodiment. 
     When it is assumed that each of through-holes  81   a ,  81   b ,  81   e ,  81   f ,  81   k ,  81   l ,  81   o  and  81   p  in upper and lower lines that holds the connector connection part  12  of the first contact  1  is set as the first hole, and each of through-holes  81   c ,  81   d ,  81   g ,  81   h ,  81   i ,  81   j ,  81   m  and  81   n  in upper and lower lines that holds the connector connection part  12  of the second contact  5  is set as the second hole, the through-holes  81   a  to  81   h  and  81   i  to  81   p  of this connector are arranged in order of the second hole, the second hole, the first hole and the first hole. Moreover, in the through-holes  81   a  to  81   p  arranged in the two lines, the second hole, the second hole, the first hole and the first hole arranged in one line are adjacent to the first hole, the first hole, the second hole and the second hole arranged in another line, respectively. Thereby, the same effects as those in the above described embodiments can be obtained. 
     As described above, the second contact  2  or  5  is used and the connector covers  3 ,  6 ,  8   a  or  8   b  are stacked as the stack members, so that a connector having various pin configuration can be easily obtained. There is no limitation in the number of main units, i.e., the same member as the first contact  1  in the second contact  2  or  5 . As long as the connector cover  3 ,  6 ,  8   a  or  8   b  has a shape in which the fixed part  11  of the contact  1 ,  2  or  5  can be press-fitted and the connector connection part  12  can be held, there is no limitation in the shape of the connector cover  3 ,  6 ,  8   a  or  8   b.    
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various change, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.