Abstract:
A circuit board edge connector includes an insulative housing and two opposing mating ends with a plurality of conductive terminals supported by the housing and extending between the two ends. One end of the connector mates with an opposing connector and the other end has a slot disposed therein that receives the mating edge of a printed circuit card or board. The terminals at the end of the connector extend outwardly in a cantilevered fashion and they terminate in free ends that contact conductive pads on the edge of the circuit card. A preload cap is provided that includes two parts that interfit with each other and with the circuit card mating end of the connector. These preload caps engage the terminal free ends and impart a preload to the terminals so that the circuit card may be easily inserted into the connector slot and the caps are subsequently removed from the connector.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to an edge connector, and more particularly to an edge connector which utilizes a preload cap in order to spread out the contact portions of the terminals prior to mating with an edge card. 
         [0002]    Conventionally, an edge connector is used as a direct type connector in which an edge, of a substrate such as a printed circuit board is directly inserted and fitted into connector, as a plug portion as shown in Japanese Patent Application Laid-Open (Kokai) No. H4-126383. 
         [0003]      FIG. 14  is a perspective view of sudl a conventional edge connector. 
         [0004]    As illustrated in  FIG. 14 , the connector has a housing  801  made of an insulating material and includes a plurality of conductive terminals  802  that are held in the housing  801 . Contact portions  803  of the terminals  802  project downward from a lower surface of the housing  801 .  810  designates a substrate such as a printed circuit board or the like having a plurality of pads  811  arranged along and where “t” designates the thickness of the substrate  810 . 
         [0005]    In this case, an angled hole  804  is formed in the center portion of the housing  801 , and the hole  804  extends in the direction of the terminals  802  and passes through the housing  801  in the thickness direction. A spacer  805  with a thickness “w” larger than the thickness “t” of the substrate  810  is inserted from above into the angled hole  804 , and the tip of the spacer  805  projects from the lower surface of the housing  801  between the contact portions  803  of the terminals  802  on both sides. The opposing contact portions  803  are forcibly spread by the tip of the spacer  805 , and the distance between the opposing contact portions  803  is equal to or greater than “w”, which is greater than the thickness “t” of the substrate  810 . 
         [0006]    As illustrated, the substrate  810  is inserted between the contact portions  803  so that the state in which the contact portions  803  are forcibly spread by the spacer  805 . In this case, the distance between the opposing contact portions  803  is larger than the thickness “t” of the substrate  810 , the contact portions  803  may not buckle or deforme due to the contact by the inserted substrate  810 . The spacer  805  is pushed up by the substrate  810  and the contact portions  803  become deformed so that the distance between them is reduced by the spring force of the contact portions  803  and sandwich the substrate  810  from both sides. Thus, the edge connector is fixed to the substrate  810 . In addition, the contact portions  803  are pressed against the connecting electrodes  811  by the spring force that the contact portions  803  have and are reliably electrically connected thereto. 
       SUMMARY OF THE INVENTION 
       [0007]    However, in the above-described conventional edge connector, since the contact portions  803  of the terminals  802  are held in the state of being forcibly spread by the spacer  805 , it is difficult to apply a preload pressure to the contact portions  803  in advance. In other words, since the spacer  805  has thickness “w” which is greater than the substrate thickness “t”, the distance between the contact portions  803  becomes larger than the thickness “t” of the substrate  810 . For this reason, for instance, when the edge connector is stored in inventory the contact portions  803  are held for a long time and are forcibly spread, a creep or elastic deformation occurs and the contact portions  803  may not be able to return to the original shape, resulting in not being able to sandwich the substrate  810  from both sides with a sufficient force. As a result, the electrical connection between the contact portions  803  and the substrate  810  is more likely to become uncertain. 
         [0008]    Furthermore, in the case of inserting the substrate  810 , since the contact portions  803  do not contact the connecting electrodes  811  until the spacer  805  is released from between the contact portions  803 , the wiping effect occurring when the contact portions  803  contact the moving connecting electrodes  811 , that is, the effect of removing the dust, foreign matters, or the like of the connecting electrodes  811  by rubbing them by the contact portions  803  may not be exerted. As a result, the connection between the contact portions  803  and the pods  811  of the substrate  810  becomes uncertain. 
         [0009]    An object of the present invention is to solve the above-described problem and to provide an edge connector with a removably attached preload cap for holding terminals such that the distance between the contact portions of the opposing terminals are set to be slightly narrower than the thickness of the substrate to be inserted, thereby the preload given to the terminals may be maintained at an appropriate level, and a creep deformation may not occur in the terminals even when the edge connector is left to stand for a long period of time, whereby the terminals may fully exert their force, sandwich and hold the contact electrodes of the substrate, insertion work of the substrate may be easily performed because the resistance received from the terminals during the insertion work is decreased, a deformation and damage to the terminals may not occur, the electrical connection state of the contact portions of the terminals and the contact electrodes are favorable due to the wiping effect, and with high durability. 
         [0010]    For solving this object, an edge connector of the present invention comprises a connector body for engaging with a counterpart connector; terminals extending from the connector body, the terminals including contact portions for contacting electrodes disposed on surfaces of a substrate; the connector body including a mounting part for attaching a removable preload cap; the contact portions being arranged in opposing rows where a distance between the opposing contact portions in an initial state is smaller than a thickness of the substrate, the distance in a state where the preload cap is attached being larger than that of the initial state and smaller than the thickness of the substrate. 
         [0011]    In a further aspect of the present invention, the contact portion includes an engaging portion at a tip thereof the preload cap includes a terminal holding portion and the engaging portion is engaged with the terminal holding portion in the state in which the preload cap is attached. 
         [0012]    In a still further aspect of the present invention, the preload cap comprises a first preload cap corresponding to one of the rows of the contact portions and a second preload cap corresponding to the other row of the contact portions and the first preload cap and the second preload cap have an identical structure to each other, and are attached to the connector housing so that they face each other. 
         [0013]    In a still further aspect of the present invention, an amount of extension of the preload cap attached to the connector body from the connector body is longer than an amount of extension of the contact portion from the connector body. 
         [0014]    In the connector according to still further aspect of the present invention, the cap mounting part has a concave portion formed in the connector body outside the mutually opposing rows of the contact portions and the preload cap further includes a fitting projection that is inserted in the cap mounting part. 
         [0015]    In the connector according to still further aspect of the present invention, the preload cap forms a substrate insertion opening into which the substrate can be inserted in the state in which the preload cap is attached to the connector body, and the preload cap can then be removed from the connector often when the substrate is inserted in the substrate insertion opening and the distance between the opposing contact portions is spread by insertion of the substrate. 
         [0016]    According to the present invention the preload cap for holding the terminals is removably attached so that the distance between the contact portions of the terminals is slightly narrower than the thickness of the inserted substrate. The preload given to the terminals may be maintained at an appropriate level, and creep deformation will not occur in the terminals even when the edge connector is left to stand for a long period of time. Hence, the terminals will fully exert their force and hold the contact electrodes of the substrate and the work of inserting the substrate is easily performed because the resistance received from the terminals during insertion is decreased, and deformation and damage to the terminals does not occur. The connection state of the contact portions and the contact electrodes is favorable due to the wiping effect, and the durability is improved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a first perspective view illustrating an edge connector according to an embodiment of the present invention in a state in which the edge connector is mounted on a substrate; 
           [0018]      FIG. 2  is the same view as  FIG. 1 , but illustrating the edge connector mounted to the substrate; 
           [0019]      FIG. 3  is a similar view to  FIG. 2 ; 
           [0020]      FIG. 4  is a cross-sectional view taken along line x-x of  FIG. 2 , and illustrating the edge connector is mounted on the substrate; 
           [0021]      FIG. 5  is a cross-sectional exploded view illustrating the edge connector before the preload cap is attached thereto; 
           [0022]      FIG. 6  is the same view as  FIG. 5 , but illustrating the edge connector after the preload cap is attached thereto; 
           [0023]      FIG. 7  is a perspective view illustrating the edge connector in with the preload caps attached thereto; 
           [0024]      FIG. 8  is the same view as  FIG. 7 , but illustrating the edge connector with the substrate is inserted into the preload cap; 
           [0025]      FIG. 9  is a cross-sectional view taken along line Y-Y of  FIG. 8 , illustrating the edge connector with the substrate is inserted and the preload caps attached thereto; 
           [0026]      FIG. 10  is a perspective view illustrating the edge connector with the preload caps removed therefrom; 
           [0027]      FIG. 11  is a first perspective view illustrating a counterpart connector of the edge connectors of the present invention; 
           [0028]      FIG. 12  is a second perspective view illustrating the opposing end of the counterpart connector of  FIG. 11 , to the embodiment of the present invention; 
           [0029]      FIG. 13  is a cross-sectional view illustrating the edge connector of the present invention mated to the counterpart connector; and 
           [0030]      FIG. 14  is a perspective view illustrating a conventional edge connector. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    Reference numeral  1  designates an edge connector of the present invention, in which an edge portion of a substrate  101  is inserted therein. The substrate  101  is a printed circuit board used in an electronic device such as a computer, or the like, or a flat cable referred to as a flexible printed circuit (FPC), a flexible flat cable (FPC), or the like. In this embodiment, the present invention is explained in terms of the substrate  101  being a printed circuit board. The substrate  101  has a plurality of connecting electrodes or pods  151  arranged at a predetermined pitch on opposite surfaces thereof along the upper edge portion. The pods  151  are connected to conductive traces (not shown) of the substrate  101 . The pitch and the number of the connecting electrodes  151  can be appropriately set. 
         [0032]    The connector  1  includes a housing  11  serving as a connector body and made of an insulating material. A plurality of terminals  51  made of conductive metal are fitted in the housing  11 . The housing  11  is an elongated member extending along the edge portion of the substrate  101  and having a rectangular cross-section. It includes a fitting portion  12  integrally formed therewith so as to extend on the opposite side (upper side in the Figure) of the substrate  101 . The fitting portion  12  is a portion that mates to a counterpart or mating connector  201 , and includes a concave portion  13  in which a convex portion  212  of the mating connector  201  is fitted. The concave portion  13  is an elongated groove-like portion having a rectangular cross-section which is open in the surface opposite to the substrate  101 . 
         [0033]    The terminals  51  are arranged along the inner wall surface of the concave portion  13 . As illustrated in  FIG. 4 , terminal receiving grooves  16  extend through the housing  11  and the portion  12  with, each terminal  51  being accommodated in a single terminal receiving groove  16 . The pitch and the number of the terminal receiving grooves  16  may be changed according to the pitch and the number of the contact pods  151  of the substrate  101 . The terminals  51  need not necessarily be fitted in all of the terminal receiving grooves  16  and the terminals  51  can be omitted according to the arrangement of the contact pods  151  of the substrate  101 . 
         [0034]    For the sake of illustration,  FIGS. 1-3  illustrate only some of the terminals  51  and contact pods  151  which are positioned on both sides of the substrate  101  in the widthwise direction. 
         [0035]    The housing  11  includes flange parts  14  integrally formed therewith that extend outward from both ends of the housing  11  on one side of the substrate  101  (lower side in the Figure) and in the longitudinal direction of the housing  11 , as well as guide parts  15  integrally formed therewith and arranged at the end surface of the housing  11  on the side of the substrate  101  in the vicinity of the ends in the longitudinal direction and extend toward the substrate  101 . The guide parts  15  are members that define the positional relationship between the ends of the substrate  101  (right and left ends in  FIGS. 1-3 ) and the housing  11 , and contact both ends of the substrate  101 . In addition, each guide parts  15  includes a first extension portion  15   a  and a second extension portion  15   b  integrally formed therewith so as to extend in the longitudinal direction of the housing  11 . As illustrated in  FIGS. 2-3 , the extent of the first extension portion  15   a  is larger than the amount of extension of the second extension portion  15   b . However, the extents of the first extension portion  15   a  and the second extension portion  15   b  may be appropriately changed. The first extension portion  15   a  and the second extension portion  15   b  contact opposite surfaces of the edge of the substrate  101  near the ends thereof and define the positional relationship of the substrate  101  in its thickness direction. The guide parts  15  guide both ends of the substrate  101  in the width direction and thickness directions relative to the housing  11 . 
         [0036]    The housing  11  includes a cap mounting part  17  formed in the end surface on the side of the substrate  101  and extending longitudinally. The cap mounting part  17  is a groove-like concave portion formed outside the terminal receiving groove  16 , and a fitting projection  22  of the preload cap  21 , (described later) is inserted in the cap mounting part  17 . 
         [0037]    As illustrated in  FIG. 4 , the terminal  51  has a contact portion  52  integrally connected to the lower end of the terminal body, which extends lineraly in the vertical direction and is fixed to the terminal receiving groove  16 . It includes a counterpart contact portion  53  integrally connected to the upper end of the terminal body and contacts a counterpart terminal  254  of a mating connector  201  in the fitting concave portion  13 . The contact portions  52  are arranged in mutually opposing rows as they are in the mating connector contact portions  53 . 
         [0038]    The counterpart contact portion  53  includes an inclined portion  53   a  and a convex portion  53   b . The inclined portion  53   a  extends obliquely upward from the upper end of the terminal body toward the center of the housing  11  in the thickness direction. In addition, the convex portion  53   b  is connected to the tip of the inclined portion  53   a  and contacts the counterpart terminal  254  of the counterpart connector  201 . When the counterpart connector  201  is fitted in the connector  1 , the distance between the convex portions  53   b  on both sides are forcibly spread, and the convex portions  53   b  press the mating terminals  254  by an urging force generated due to resilient deformation mainly of the inclined portion  53   a  and the connection portion of the terminal body and the inclined portion  53   a.    
         [0039]    The contact portion  52  has, as a whole, a mountain shape or a shape with a central peak and gentle slopes, with a first inclined portion  52   a , a convex portion  52   b , a second inclined portion  52   c , and an engaging portion  52   d . The first inclined portion  52   a  extends obliquely downward from the lower end of the body toward the center of the housing  11  in the thickness direction. The second inclined portion  52   c  is connected to the tip of the first inclined portion  52   a  and inclined in a reverse direction to that of the first inclined portion  52   a . The convex portion  52   b  is a connecting portion of the first inclined portion  52   a  and the second inclined portion  52   c , and in the illustrated embodiment, it is a portion bent approximately at 90 degrees and contacting the connecting electrode  151  of the substrate  101 . In addition, the engaging portion  52   d  is connected to the tip of the second inclined portion  52   c , extends nearly parallel to the terminal body in the initial state, and engages with a terminal holding portion  24  of the preload cap  21 . 
         [0040]    As illustrated in the Figures, the distance between the opposing convex portions  52   b  of the terminals are forcibly spread in the state in which the connector  1  is mounted on the substrate  101 , and the convex portions  52   b  presses the connecting electrodes  151  by the urging force generated due to the resilient deformation mainly of the first inclined portions  52   a  and the connection portions of the terminal bodies and the first inclined portions  52   a . Thereby, the connecting state of the terminals  51  to the connecting electrodes  151  is reliably maintained. In addition, the state in which the connector  1  is mounted on the substrate  101  is maintained when the substrate  101  is sandwiched by the opposing contact portions  52 . In addition, the terminals  51  and the connecting electrodes  151  can be secured by a securing means such as soldering, or the like. In this case, the electrical connecting state of the terminals  51  to the connecting electrodes  151  can be reliably maintained and the mounting state of the connector  1  on the substrate  101  can be more reliably maintained. 
         [0041]    Next, the structure of the preload cap  21  will be explained. 
         [0042]    As illustrated in  FIGS. 5 ,  7  &amp;  8 , a first preload cap  21 A and a second preload cap  21 B are mounted on the connector  1 . The first preload cap  21 A and the second preload cap  21 B have an identical structure, and members belonging to the first preload cap  21 A are allocated a designation of “the first” and appended with the letter “A”, and members belonging to the second preload cap  21 B are allocated a designation of “the second” and appended with the letter “B” for differentiation. It is to be noted that when explanation is made without differentiating the members belonging to the first preload cap  21 A from those of the second preload cap  21 B, the designation of “the first” and “the second” and the letters “A” and “B” will be omitted. 
         [0043]    The preload cap  21 A and the preload cap  21 B include elongated rectangular bodies extending longitudinally of the housing  11 , and first end wall portions  23 A and second end wall portions  23 B extending perpendicularly to the bodies are connected to opposite longitudinal ends of the bodies. As illustrated in  FIG. 6 , the first preload cap  21 A and the second preload cap  21 B form a rectangular tube having an elongated rectangular cross-section extending longitudinally along the housing  11 . The first preload cap  21 A and the second preload cap  21 B are arranged to face each other. When the first preload cap  21 A and the second preload cap  21 B are mounted on the connector  1 , the bodies which form a pair of elongated side walls cover the outside of the contact portions  52  of the terminals  51 . The end wall portions  23  form a pair of short side walls and cover the outside of the guide parts  15  on opposite ends. An elongated rectangular substrate insertion opening  26  is formed between the first preload cap  21 A and the second preload cap  21 B. Inclined surfaces  27  for guiding the end of the substrate  101  into the substrate insertion opening  26  are formed on the inside ends of the end wall portions  23  on the opposite side of the connector  1  (left side of  FIGS. 5-6 ). 
         [0044]    The length of the preload cap  21  is longer than the amount of extension of the contact portion  52  of the terminal  51  from the end surface of the housing  11  so that the terminal contact portion  52  are protected by the preload cap  21  and are not be damaged by the contact with fingers of an operator, tools, other peripheral devices, or the like. 
         [0045]    In addition, the preload cap  21  includes a fitting projection  22  integrally formed therewith so that it projects from the end surface of the body on the side of the connector  1  toward the connector  1  and extends longitudinally of the body. The preload cap  21  is attached to the housing  11  of the connector  1  when the fitting projection  22  is inserted in the cap mounting part  17  of the housing  11 . 
         [0046]    The preload cap  21  also includes a terminal holding portion  24  integrally formed therewith that projects from the inner end of the body on the opposite side of the connector  1  and extends longitudinally of the body. The terminal holding portion  24  has a terminal insertion hole  25  formed therein which extends through the terminal holding portion  24 . When the preload cap  21  is attached to the connector  1 , the engaging portions  52   d  of the contact portions  52  of the terminals  51  are inserted in the terminal insertion hole  25  and secured by the terminal holding portion  24 . The amount of extension of the terminal holding portion  24  toward the center in the thickness direction is set such that the distance between the convex portions  52  of the contact portions  52  on opposite sides becomes a value T 2  which is slightly greater than a value T 1  in the initial state as illustrated in  FIG. 5 . 
         [0047]    The distance between the first terminal holding portion  24 A and the second terminal holding portion  24 B is set to be greater than the value tx of thickness of the substrate  101 , which will be described later. Thereby, since the size of the substrate insertion opening  26  in the thickness direction becomes greater than the value tx of the thickness of the substrate  101 , the substrate  101  can be easily inserted therein. 
         [0048]    The first preload cap  21 A and the second preload cap  21 B can be separately and sequentially attached to the connector  1 , as illustrated in  FIG. 5 . An operator relatively moves the first preload cap  21 A toward the connector  1 , as indicated by arrow P 1  of  FIG. 5 . The operator may insert the first fitting projection  22 A in the upper cap mounting part  17  of the housing  11 , and insert the engaging portions  52   d  of the upper terminals  51  into the first terminal insertion hole  25 A so that the engaging portions  52   d  engage with the first terminal holding portion  24 A. Subsequently, the operator holds the second preload cap  21 B with hands or fingers and moves it toward the connector  1 , as indicated by the arrow P 2 . The operator may then insert the second fitting projection  22 B in the lower cap mounting part  17  of the housing  11 , and insert the engaging portions  52   d  of the lower terminals  51  into the second terminal insertion hole  25 B so that the engaging portions  52   d  engage the second terminal holding portion  24 B. 
         [0049]    As illustrated in  FIG. 6 , the preload cap  21  is attached to the connector  1 . The engaging portions  52   d  are engaged with the terminal holding portion  24  and the opposing convex portions  52   b  are spread so that the distance therebetween becomes the value T 2  which is slightly greater than the value T 1  in the initial state. The opposing engaging portions  52   d  sandwich the first terminal holding portion  24 A and the second terminal holding portion  24 B by an urging force generated due to a resilient deformation of the first inclined portions  52   a  and the connection portions of the terminal bodies and the first inclined portions  52   a . Accordingly, the attachment of the preload cap  21  to the connector  1  is reliably maintained by the urging force generated by the terminals  51 . 
         [0050]    In addition, when viewed from the side of the terminals  51 , a load that can resiliently deform mainly the first inclined portions  52   a  and the connection portions of the terminal bodies and the first inclined portions  52   a  is given to the terminals  51  as a pre-load pressure, that is, a preload when the engaging portions  52   d  are engaged with the terminal holding portion  24 . In this case, the distance T 2  between the opposing convex portions  52   b  is set to be smaller than the value tx of the thickness of the substrate  101 . Therefore, since the amount of deformation of the terminals  51  is small in the state when the preload cap  21  is attached and the preload is given to the terminal  51 , a creep deformation will not occur in the terminals  51  even when the connector is left to stand for a long period of time. Accordingly, as described above, a creep deformation may not occur in the terminals  51  and the terminals  51  can maintain a sufficient elastic force even when the connector  1  is stored for a long period of time in the state in which the preload cap  21  is attached thereto. 
         [0051]    The operator relatively moves the substrate  101  and inserts the edge portion of the substrate  101  on the side in which the contact pods  151  of the substrate  101  are disposed into the rectangular tube having the elongated rectangular cross-section formed by the first second preload caps  21 A  21 B facing each other. In  FIG. 7 , a rectangular cutaway portion  111  is formed in one end of the edge portion of the substrate  101 . The cutaway portion  111  abuts against the edge of the guide part  15  of the housing  11  and defines the length of insertion of the substrate  101  in between the terminals  51 . It is to be noted that the cut-away portion  111  may be formed in both ends of the edge portion of the substrate  101 , or may be omitted. 
         [0052]    In this case, since the both ends of the edge portion of the substrate  101  are guided by the inclined surfaces  27  formed in the end wall portions  23  of the preload cap  21 , the edge portion of the substrate  101  can be easily inserted. When the substrate  101  is further moved into the connector  1 , both ends of the edge portion of the substrate  101  will be guided by the first extension portion  15   a  and the second extension portion  15   b  of the guide part  15  of the housing  11 . Thus the positional relationship relative to the housing  11  in the width and thickness directions of the substrate  101  are defined, and the connecting electrodes  151  exposed to opposite surfaces of the edge portion of the substrate  101  are reliably set at the position facing the contact portions  52  of the corresponding terminals  51 . 
         [0053]    When the substrate  101  is completed by inserted as shown in  FIG. 9 , it enters between the terminal contact portions  52  and forcibly spreads the convex portions  52   b  of the contact portions  52  apart. When the engaging portion  52   d  is engaged by the terminal holding portion  24 , the distance T 2  of the convex portions  52   b  on opposite sides is smaller than the value tx of thickness of the substrate  101 , the distance between the convex portions  52   b  is forcibly spread by the substrate  101 , and the engaging portions  52   d  are in the state of being separated from the terminal holding portions  24 . 
         [0054]    In addition, since the size of the substrate insertion opening  26  in the thickness direction is set to be greater than the value tx of the thickness of the substrate  101 , the substrate  101  can be inserted therein without contacting the terminal holding portion  24 . 
         [0055]    The substrate  101  enters between the opposing contact portions  52  when the distance between the convex portions  52   b  of the contact portions  52  at T 2  (which is greater than T 1  in the initial state) that is, in the state in which preload is given to the terminals  51 , the resistance incurred by the substrate  101  from the terminals  51  decreases as compared to that when the substrate  101  enters between the contact portions  52  in the initial state. The insertion of the substrate  101  is easily performed. The resistance received by the substrate  101  from the terminals  51  is small and the substrate  101  will not be damaged. Likewise the reaction force received by the terminals  51  from the substrate  101  is small and the terminals  51  may will not be deformed or be damaged. 
         [0056]    The contact pods  151  move relative to the convex portions  52   b  when the convex portions are pressed against the contact pods  151  by an urging force generated due to the resilient deformation of the terminals  51  when the substrate  101  enters between the contact portions  52 . The wiping effect is generated when the convex portions  52   b  contact the moving contact pods  151  in the state of being pressed and dust, foreign matters, or the like, is removed by being rubbed by the convex portion  52   b . Likewise, the dust, foreign matters, or the like of the convex portion  52   b  may be removed when being rubbed by the contact pods  151 . 
         [0057]    The convex portions  52   b  press the pods  151  by an urging force and the electrical connecting state of the terminals  51  and the pods  151  is reliably maintained. Creep deformation will not occur in the terminal  51  and since the terminals  51  maintain a sufficient elastic force, the urging force is large enough. Accordingly, the terminal convex portions  52   b  press the contact pods electrodes  151  with a sufficiently large force and the contact portions  52  on opposite sides sandwich the substrate  101  with a sufficiently large force. 
         [0058]    Subsequently, the operator removes the preload cap  21  from the connector  1 . The operator removes the first preload cap  21 A from the connector  1 , as indicated by the arrow P 3 , and further relatively removes the second preload cap  21 B from to the connector  1 , as indicated by the arrow P 4 . Since the distance between the convex portions  52   b  is then spread and the engaging portions  52   d  are separated from the terminal holding portions  24 , the urging force generated by the terminals  51  does not act on the preload cap  21 , and therefore the preload cap  21  is freely movable. The preload cap  21  is then easily removed from the connector  1 . ( FIG. 10 ) 
         [0059]    In the case of securing the terminals  51  and the connecting electrodes  151  by soldering, a solder layer is formed in the surface of the contact pods  151  in advance. The preload cap  21  is removed from the connector  1  and the solder is reflowed by accommodating the connector  1  and substrate  101  in a furnace. Thereby, the connecting state of the terminals  51  and the substrate  101  to the contract pods  151  is reliably maintained. 
         [0060]    The counterpart connector  201  includes a counterpart housing  211  made of an insulating material and a plurality of conductive terminals  254  which are fitted in the counterpart housing  211 . The counterpart housing  211  is also an elongated member and as illustrated in  FIG. 12 , a fitting opening  214  is formed in the fitting surface and includes a convex portion  212  disposed in the opening  214 . As illustrated in  FIG. 13 , the fitting portion  12  of the connector  1  is fitted in the opening  214  and the convex portion  212  is fitted in the fitting portion  12  when the connector  1  and the counterpart connector  201  are mated together. 
         [0061]    The counterpart housing  211  includes wire insertion openings  213  that open to the surface on the opposite side of the fitting surface (upper surface in  FIG. 11 ). Tips of wires  251  such as coaxial cables, or the like, are accommodated in these openings  213 . The wire terminals  253  are connected to the tips of the wires  251  and the terminals  253  are engaged in the insertion openings  213 . The wire terminals  253  are connected to the corresponding counterpart terminals  254 , and thus, each of the wires  251  is connected to a counterpart terminal  254 . 
         [0062]    When the connector  1  and the counterpart connector  201  are mated together, the convex portion  212  enters between the contact portions  53  on the opposite sides. The distance between the convex portions  53   b  on the opposite sides is spread apart and the convex portions  53   b  press the counterpart terminals  254  by the urging force generated due to a resilient deformation of the inclined portions  53   a  and the connection portions of the connector bodies. The connection of the terminals  51  and counterpart terminals  254  is reliably maintained. When the counterpart contact portions on the opposite sides sandwich the convex portions  212 , the mating state of the connector  1  and the counterpart connector  201  is reliably maintained. 
         [0063]    In addition, the wires  251  such as coaxial cables, or the like, are not necessarily be connected to the counterpart connector  201 , and for instance, a flat cable such as an FPC, an FFC, or the like, may be connected thereto. 
         [0064]    The housing  11  of the connector  1  includes a cap mounting part  17  for attaching the preload cap  21  and the contact portions of the terminals  51  are arranged in opposing rows, and the distance between the opposing contact portions  52  in the initial state is smaller than the thickness of the substrate  101 , while the distance in a state in which the preload cap  21  is attached is larger than that in the initial state and smaller than the thickness of the substrate  101 . 
         [0065]    The preload given to the terminals  51  may be maintained to an appropriate amount so that creep deformation will not occur in the terminals  51  even when the connector is left to stand for a long period of time, such as in inventory. Accordingly, the terminals  51  will always a force sufficient to sandwich the substrate  101 . The resistance received by the substrate  101  during an insertion is reduced and the insertion is easily performed, and a deformation or damage may not occur in the terminals  51 . Further, the electrical connecting state of the contact portions  52  of the terminals  51  and the connecting electrodes  151  becomes favorable due to the wiping effect. 
         [0066]    In addition, the contact portion  52  includes the engaging portion  52   d  at the tip thereof, the preload cap  21  includes the terminal holding portion  24 , and the engaging portion  52   d  is engaged with the terminal holding portion  24  in the state in which the preload cap  21  is attached. Thereby, a preload is given to the terminals  51  and the terminals  51  can resiliently and elastically deform. In addition fitting of the preload cap  21  to the connector  1  may be reliably maintained by the urging force generated by the terminals  51 . 
         [0067]    The preload cap  21  includes the first preload cap  21 A and the second preload cap  21 B, both of which are preferably identical to each other and are attached to the housing  11  so they face each other. Accordingly, the structure of the preload cap  21  is simplified and the preload cap  21  may be manufactured at a low cost. The first preload cap  21 A and the second preload cap  21 B form what may be considered as a tube for covering the outside of the opposing rows of the contact portions  52 . The length of the preload cap  21  away from the housing  11  is greater than the length the terminal contact portions  52  external from the housing  11 . Thus the contact portions  52  of the terminals  51  are protected by the preload cap  21  and are not be damaged by contact with fingers of an operator, tools or the like. 
         [0068]    The preload cap  21  forms the substrate insertion opening  26  into which the substrate  101  can be inserted in the state in which the preload cap  21  is attached to the housing  11 , and the preload cap  21  can be removed from the housing  11  when the substrate  101  is inserted in the substrate insertion opening  26  and the distance between the opposing contact portions  52  is spread by the insertion of the substrate  101 . Thereby, the insertion work of the substrate  101  and the fitting operation of the preload cap  21  may be easily performed. 
         [0069]    The present invention is not limited to the above-described embodiments, and may be changed in various ways based on the gist of the present invention, and these changes are not eliminated from the scope of the present invention.