Abstract:
An electric connector includes: a soldering portion, to be soldered to a substrate, and extending in a first direction; a rising portion, one end of which is connected to one end of the soldering portion, and extending in a second direction perpendicular to the first direction; an elastic portion, one end of which is connected to the other end of the rising portion, and including at least one bending part; and a receiving portion, adapted to receive a plug, and having a U-shape including an open end and a closed end, the open end provided with contact parts which are opposed to each other in a third direction perpendicular to the first and second directions, the closed end connected to the elastic portion. The soldering portion, the rising portion, the elastic portion and the receiving portion are integrally formed with each other.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a small electric connector which is used for electric connection of electronic equipment and into which a plug terminal is inserted for such electric connection. 
         [0002]    For detachable attachment of a battery pack to electronic equipment, a type of an electric connector that enables the battery pack to be electrically connected with and disconnected from electronic equipment is generally used. As an example of such a technique, an electric connector is disclosed in JP-A-2006-19296. This related-art technique disclosed in JP-A-2006-19296 is such that a plug receiving portion of sheet metal into which a plug terminal is inserted is formed on a base member via a spring member with an integrated manner. In describing the construction thereof in detail, the sheet metal is bent in a thickness direction into a substantially U-shape on both lateral external sides of the plug receiving portion, and each distal end of the sheet metal which is bent into the substantially U-shape is bent further in the thickness direction into a substantially U-shape on a lateral external side thereof, so as to form the spring member, and a lower end portion at a distal end of the spring member is bent in the thickness direction, so as to form the base member. This base member is fixed to a substrate by means of soldering. In this configuration, the spring member is elastically deformed in the thickness direction, and the bend of the substantially U-shaped bent portion is deformed, whereby the plug receiving portion can easily be shifted laterally to both sides thereof. Then, when the plug terminal is inserted into or removed from the plug receiving portion, even though the plug terminal is offset in a lateral direction relative to the plug receiving portion, thereby exerting a lateral force on the plug receiving portion, the lateral force so exerted is absorbed by the elastic deformation of the spring member, and no large lateral force is exerted on the base member which is fixed to the substrate. Therefore, there is caused no such an accident that the base member is separated from the substrate. 
         [0003]    In electronic equipment such as a small mobile phone, in many cases, a plurality of such electric connectors are provided in such a manner as to be aligned horizontally. When the related art described in JP-A-2006-19296 is applied to such alignment of connector, the overall width or lateral dimension of the plug receiving portion has to be increased to quite a large extent, since the spring members are provided on both the lateral external sides of the plug receiving portion. Thus, the related-art technique described in JP-A-2006-19296 is not suitable for a configuration in which electric connectors are aligned at small intervals. This constitutes a cause for hindrance to the miniaturization of electronic equipment such as the mobile phone for which miniaturization is strongly demanded. 
       SUMMARY 
       [0004]    It is therefore an object of the invention to provide an electric connector with a plug receiving portion having a reduced lateral dimension so that the overall length of the alignment connector is decreased. 
         [0005]    In order to achieve the object, according to the invention, there is provided an electric connector, comprising: 
         [0006]    a soldering portion, to be soldered to a substrate, and extending in a first direction; 
         [0007]    a rising portion, one end of which is connected to one end of the soldering portion, and extending in a second direction perpendicular to the first direction; 
         [0008]    an elastic portion, one end of which is connected to the other end of the rising portion, and including at least one bending part; and 
         [0009]    a receiving portion, adapted to receive a plug, and having a U-shape including an open end and a closed end, the open end provided with contact parts which are opposed to each other in a third direction perpendicular to the first and second directions, the closed end connected to the elastic portion, wherein 
         [0010]    the soldering portion, the rising portion, the elastic portion and the receiving portion are integrally formed with each other. 
         [0011]    The open end of the receiving portion may be opened in the second direction. 
         [0012]    The closed end of the receiving portion may be connected to the other end of the elastic portion. The other end of the elastic portion may extend in the first direction. 
         [0013]    The elastic portion may include two of the bending parts so as to have an S-shape. 
         [0014]    A width of the one end of the elastic portion may be greater than a width of the other end of the elastic portion in the third direction. 
         [0015]    The elastic portion may be formed with a first slit so as to be divided into two pieces. 
         [0016]    The rising portion may be formed with a second slit connected to the first slit. 
         [0017]    The elastic portion maybe disposed between the receiving portion and the rising portion in the first direction. 
         [0018]    The soldering potion may be formed with a projecting part capable of being in contact with the closed end of the receiving portion. 
         [0019]    The closed end of the receiving portion may be formed with an engagement part extending in the second direction. The soldering portion may be provided with a projecting part capable of being in contact with the engagement part. 
         [0020]    The open end of the receiving portion may be opened in the first direction. 
         [0021]    The electric connector may further include a restricting portion, having a U-shape covering the receiving portion. 
         [0022]    The elastic portion may be formed with a first slit so as to be divided into two pieces. 
         [0023]    The rising portion may be formed with a second slit connected to the first slit. 
         [0024]    The elastic portion may be disposed between the receiving portion and the rising portion in the first direction. 
         [0025]    The other end of the elastic portion may extend in the first direction. The soldering potion may be formed with a projecting part capable of being in contact with the other end of the elastic portion. 
         [0026]    The other end of the elastic portion may be formed with an engagement part extending in the second direction. The soldering potion may be formed with a projecting part capable of being in contact with the engagement part. 
         [0027]    According to the invention, there is provided a connector unit incorporating a plurality of the electric connector arranged on the substrate in the third direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is an external perspective view of an electric connector of a first embodiment of the invention as viewed from a forward obliquely upward position. 
           [0029]      FIG. 2  is an external perspective view of the electric connector in  FIG. 1  as viewed from a rearward obliquely downward position. 
           [0030]      FIGS. 3A ,  3 B and  3 C are three-plane drawings of the electric connector in  FIG. 1 ,  FIG. 3A  is a plan view,  FIG. 3B  is a front view and  FIG. 3C  is a right side view of the electric connector. 
           [0031]      FIG. 4  is an external perspective view of a connector unit which is made up by aligning horizontally three electric connectors like the electric connector shown in  FIG. 1 . 
           [0032]      FIG. 5  is an external perspective view of a battery pack in which the connector unit in  FIG. 4  is packaged and a plug terminal unit which is inserted into the connector unit. 
           [0033]      FIG. 6  is an external perspective view showing a state in which the plug terminal unit is inserted in the connector unit with a casing of the plug terminal unit partially cut away. 
           [0034]      FIGS. 7A and 7B  are drawings illustrating a leftward displacement of a plug receiving portion which occurs when a plug terminal inserted into the electric connector is offset to the left as viewed in the figure relative to the electric connector. 
           [0035]      FIGS. 8A and 8B  are drawings illustrating a rightward displacement of the plug receiving portion which occurs when the plug terminal inserted into the electric connector is offset to the right as viewed in the figure relative to the electric connector. 
           [0036]      FIG. 9  is a drawing illustrating the restriction of an excessive elastic downward displacement of the plug receiving portion. 
           [0037]      FIG. 10  is a drawing illustrating the restriction of an excessive elastic displacement of the plug receiving portion to one side of a soldering portion. 
           [0038]      FIG. 11  is an external perspective view of an electric connector of a second embodiment of the invention as viewed from a forward obliquely upward position. 
           [0039]      FIG. 12  is an external perspective view of an electric connector of a third embodiment of the invention as viewed from a forward obliquely upward position. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0040]    Hereinafter, a first embodiment of the invention will be described by reference to  FIGS. 1 to 10 . 
         [0041]    Firstly, as is shown in  FIGS. 1 to 3C , in a first embodiment of the invention, an electric connector  10  is made of a sheet material having conductivity and elasticity, and a rising portion  16  is formed by bending the sheet material at one end (a rear end as viewed from the front) of a soldering portion  14  which is to be placed on a surface of a substrate  12 , which will be described later, so as to be fixed thereto by means of soldering in a thickness direction in such a manner as to be directed upwards of the substrate at substantially right angles to the surface of the substrate  12 . The sheet material is bent further at an upper end of the rising portion  16  in the thickness direction towards the other end (a front end as viewed from the front) of the soldering portion so as to form a first elastic portion  18 . The first elastic portion  18  is bent in the thickness direction into a substantially S-shape as viewed from a side thereof, and the sheet material is made to be directed substantially forwards again at a distal end of the first elastic portion  18  and is dimensionally narrowed in a width-ward or lateral direction so as to form a second elastic portion  20  which is substantially parallel to the substrate  12  (note that in this first embodiment, the length of the second elastic portion  20  is short). Furthermore, both lateral sides of the sheet material is bent in the thickness direction into a substantially U-shape or a substantially angular U-shape in such a manner as to define an opening above the substrate so as to form a plug receiving portion  22  at a distal end of the second elastic portion  20 . Contact portions  24  which project inwards are provided, respectively, on surfaces of confronting lateral sides of this plug receiving portion  22 . In addition, an upper edge and a front edge of the plug receiving portion  22  are formed into a curved surface which expands outwards. Furthermore, a longitudinal slit is provided on a portion of the sheet material which extends from an upper portion of the rising portion  16  to the first elastic portion  18  laterally centrally thereof so that the portion in question is divided into two parallel elastic pieces  18   b,    18   b.  In addition, a projecting portion  26  which projects upwards is formed at the other end of the soldering portion  14 , and an extended portion of the sheet material which is extended further forwards from a part of a front end portion of the plug receiving portion  22  is bent downwards in the thickness direction, so as to form an engagement portion  28 . In addition, as is shown in the side view of  FIG. 3C , the electric connector  10  is formed in such a manner that a certain space is provided between a bottom portion and the projecting portion  26  of the plug receiving portion  22  and that the engagement portion  28  lies further forwards than the projecting portion  26 . 
         [0042]    In the first embodiment that is configured as has been described above, as is shown in  FIG. 4 , three electric connectors  10  are aligned horizontally on the substrate  12  and soldering portions  14  of these electric connectors are fixed to the substrate  12  by means of soldering, whereby a connector unit  30  is made up. In  FIG. 4 , reference numeral  32  denotes a cover, made from an insulating resin, which is adapted to cover the electric connectors  10  and is, of course, provided with holes opened to face plug receiving portions  22  for allowing plug terminals  38  to be inserted into their corresponding plug receiving portions  22 . Then, as is shown in  FIG. 5 , this connector unit  30  is incorporated in a battery pack  34 , as an example, and this battery pack  34  is made to be attached to and detached from electronic equipment such as a mobile phone, whereby plug terminals  38  of a plug terminal unit  36  which is installed in the electronic unit can individually be inserted into their corresponding plug receiving portions  22  of the electric connectors  10  of the connector unit  30 . 
         [0043]    When the plug terminals  38  of the plug unit  36  are individually inserted into the plug receiving portions  22  of the electric connector  10 , particularly in the event that the plug terminals  38  and the plug receiving portions  22  are positioned properly relative to each other, the plug receiving portions  22  are elastically deformed in such a manner that their substantially U-shapes or substantially angular U-shapes are slightly opened so as to permit the insertion of the plug terminals  38  thereinto. In this case, no particular force which attempts to shift the plug receiving portions  22  in the lateral direction is exerted thereon, there will be caused no problem. In reality, however, the battery pack  34  is not always installed in a predetermined position relative to the plug terminals  38 , and in many cases, the battery pack  34  is installed in such a state that it is offset relative to the plug terminals  38 . In the state where the battery pack  34  is installed to be offset relative to the plug terminals  38 , the plug receiving portions  22  need to be elastically deformed in such a way as to match the offset so as to absorb it. This is because, in the event that the offset is not absorbed, a force attributed to the offset is exerted between the soldering portion  14  and the substrate  12 , thereby causing a fear that the solder portion  14  is separated from the substrate  12  to disturb the ensured electric connection. 
         [0044]    Then, in the electric connector  10  of the invention, an elastic displacement of the contact portions  24  of the plug receiving portion  22  relative to the soldering portion  14  due to the offset of the plug terminal  38  will be described by reference to  FIGS. 7A to 8B . Firstly, in  FIGS. 7A and 7B , a case will be described in which the plug terminal  38  is offset to the left as viewed in the figure relative to the electric connector  10 . A direction of the offset is indicated by an arrow A in  FIG. 7B . To absorb the offset, as viewed from the front, the left contact portion  24  may only have to be displaced to the left relative to the soldering portion  14 . Then, in the first elastic portion  18 , the right elastic piece  18   b  is elastically displaced in such a way that its distal end is positioned slightly forwards and upwards, while the left elastic piece  18   a  is elastically displaced in such a way that its distal end is positioned slightly rearwards and downwards. In addition, in  FIG. 7A , the whole of the rising portion  16  is slightly twisted clockwise about an axis which is perpendicular to a surface of a sheet of paper on which the figure is drawn, and in  FIG. 7B , the portion extending towards the front of the first elastic portion  18  is twisted as a whole slightly counterclockwise about an axis perpendicular to a surface of the sheet of paper on which the figure is drawn. Furthermore, in  FIG. 7A , the substantially S-shaped portion of the first elastic portion  18  which so looks as viewed from the side thereof is twisted as a whole slightly clockwise about an axis perpendicular to the surface of the sheet of paper on which the figure is drawn, and moreover, in  FIG. 7B , the second elastic portion  20  is twisted counterclockwise about an axis perpendicular to the surface of the sheet of paper on which the figure is drawn. By a series of these actions, the plug receiving portion  22  can be shifted to the left relative to the soldering portion  14  through the torsion of the rising portion  16 , the first elastic portion  18  and the second elastic portion  20 , as well as the elastic deformation of the first elastic portion  18  due to extension and contraction thereof, whereby the offset of the plug terminal  38  can easily be absorbed. 
         [0045]    In addition, in  FIGS. 8A and 8B , a case will be described in which the plug terminal  38  is offset to the right as viewed in the figure relative to the electric connector  10 . A direction of the offset is indicated by an arrow B in  FIG. 8A . To absorb the offset, as with the case described by reference to  FIGS. 7A and 7B , as viewed from the front, the right contact portion  24  may only have to be displaced to the right relative to the soldering portion  14 . Then, in the first elastic portion  18 , the right elastic piece  18   b  is elastically displaced in such a way that its distal end is positioned slightly rearwards and downwards, while the left elastic piece  18   a  is elastically displaced in such a way that its distal end is positioned slightly forwards and upwards. In addition, in  FIG. 8A , the whole of the rising portion  16  is slightly twisted counterclockwise about an axis which is perpendicular to a surface of a sheet of paper on which the figure is drawn, and in  FIG. 8B , the portion extending towards the front of the first elastic portion  18  is twisted as a whole slightly clockwise about an axis perpendicular to a surface of the sheet of paper on which the figure is drawn. Furthermore, in  FIG. 8A , the substantially S-shaped portion of the first elastic portion  18  which so looks as viewed from the side thereof is twisted as a whole slightly counterclockwise about an axis perpendicular to the surface of the sheet of paper on which the figure is drawn, and moreover, in  FIG. 8B , the second elastic portion  20  is twisted clockwise about an axis perpendicular to the surface of the sheet of paper on which the figure is drawn. By a series of these actions, the plug receiving portion  22  can be shifted to the right relative to the soldering portion  14  through the torsion of the rising portion  16 , the first elastic portion  18  and the second elastic portion  20 , as well as the elastic deformation of the first elastic portion  18  due to extension and contraction thereof, whereby the offset of the plug terminal  38  can easily be absorbed. 
         [0046]    Furthermore, in inserting the plug terminal  38 , as is shown in  FIG. 9 , when an excessive force indicated by an arrow F 1  and directed vertically downwards relative to the substrate  12  is exerted on the plug receiving portion  22 , the plug receiving portion  22  is elastically displaced downwards, and the bottom portion thereof comes into abutment with the projecting portion  26 , whereby a further elastic displacement of the plug receiving portion  22  is restricted. Thus, there is caused no such a situation in which plastic deformation is caused by an excessive elastic deformation of the plug receiving portion  22 . In addition, in inserting the plug terminal  38 , as is shown in  FIG. 10 , when an excessive force indicated by an arrow F 2  and directed rearwards in substantially parallel with the substrate  12  is exerted on the plug receiving portion  22 , while the plug receiving portion  22  is elastically displaced rearwards, the engagement portion  28  provided at the distal end thereof comes into abutment with the projecting portion  26 , whereby a further elastic displacement of the plug receiving portion  22  is restricted. Thus, there is caused no such a situation in which plastic deformation is caused by an excessive s elastic deformation of the plug receiving portion  22 . 
         [0047]    The electric connector  10  of the invention is configured and operates as has been described heretofore and is suitable for an application in which the plug terminal  38  is inserted from above substantially vertically and from the front obliquely. In addition, since the construction which can shift the plug receiving portion  22  laterally relative to the soldering portion  14  is provided entirely behind the plug receiving portion  22  as viewed from the front and no structural portion is provided which projects laterally outwards from both the external sides of the plug receiving portion  22 , the lateral dimension of the electric connector  10  can be made small. Then, even when the plurality of electric connectors  10  are aligned horizontally on the substrate  12 , the intervals at which the electric connectors  10  are so aligned may only have to be small. Consequently, the lateral dimension of the connector unit  30  is allowed to be small, and hence, the electric connector  10  of the first embodiment is suitable for miniaturization thereof. 
         [0048]    Next, a second embodiment of the invention will be described by reference to  FIG. 11 . In  FIG. 11 , like reference numerals will be imparted to like members to those described in  FIGS. 1 to 10 , and a repeated description thereof will be omitted here. In  FIG. 11 , an electric connector  40  of the second embodiment differs from that of the first embodiment in that a first elastic portion  42 , which is formed by bending a sheet material in a thickness direction towards the front at a portion upwards of a rising portion  16 , is made up of a single narrow elastic piece. In this second embodiment, a plug portion  22  is elastically displaced in a lateral direction mainly through torsion of the first elastic portion  42 . 
         [0049]    Furthermore, a third embodiment of the invention will be described by reference to  FIG. 12 . In  FIG. 12 , like reference numerals will be imparted to like members to those described in  FIGS. 1 to 10 , and a repeated description thereof will be omitted here. In  FIG. 12 , in an electric connector  50  of the third embodiment, a first elastic portion  52  is formed by bending a sheet material in a thickness direction into a substantially U-shape at a portion upwards of a rising portion  16 , and a slit is provided laterally centrally in a portion of the sheet material which extends from part of an upper portion of the rising portion  16  to the first elastic portion  52 , whereby the first elastic portion  52  is divided into two parallel elastic pieces  52   a,    52   b.  Furthermore, a plug receiving portion  54  of a substantially U-shape or substantially angular U-shape is formed from intermediate portions along downward lengths of the two elastic pieces  52   a,    52   b  in such a manner as to define an opening at the front thereof, and contact portions  24  which project inwardly are formed on both confronting sides of the plug receiving portion  54 . Furthermore, the sheet material is bent forwards in the thickness direction at a lower portion of the plug receiving portion  54  so as to form an extended portion, and both lateral sides of the sheet material are bent upwards in the thickness direction at a portion of the extended portion which is formed substantially parallel to a soldering portion  14  so as to form a substantially U-shaped or substantially angular U-shaped restricting portion  56  in such a manner as to be made to open upwards. Inner surfaces of confronting sides of the restricting portion  56  are formed in such a manner as to be brought into contact, respectively, with outer surfaces of confronting sides of the plug receiving portion  54 , or as to be positioned to confront the outer surfaces of the plug receiving portion  54  with an appropriate space defined therebetween. That is, the plug receiving portion  54  is covered by the restricting portion  56 . Furthermore, the sheet material is extended further forwards at a distal end of part of the restricting portion  56  and the extended portion is then bent downwards so as to form an engagement portion  28 . 
         [0050]    The electric connector  50  of the third embodiment of the invention which is configured as has been described above is suitable for an application in which a plug terminal  38  is inserted in a substantially parallel direction with a substrate  12 . In addition, the substantially U-shape or substantially angular U-shape of the plug receiving portion  54  is opened by the elastic pieces  52   a,    52   b  being twisted in association with a relative lateral offset of the plug terminal  38 , whereby the contact portions  24  are also offset in the lateral direction, whereby the relative offset of the inserted plug terminal  38  can be absorbed. Moreover, the opening of the substantially U-shape or the like of the plug receiving portion  54  due to its elastic deformation is restricted by the restricting portion  56  as required, whereby there is caused no situation in which a plastic deformation is generated by an excessive opening of the plug receiving portion  54 . 
         [0051]    While in the embodiments, the sheet material is bent towards the soldering portion  14  at the upper portion of the rising portion  16  so as to form the elastic portion  18 ,  42 ,  52 , the invention is not limited to the configuration, and hence, although a depth dimension of the electric connector becomes long, the sheet material may be bent towards an opposite side to the soldering portion  14  at the upper portion of the rising portion  16  to form the elastic portion  18 ,  42 ,  52 . In addition, it will suffice that a plurality of electric connectors  10  of the invention may be aligned on the substrate  12  of the connector unit  30 , and hence, the number of electric connectors to be so aligned is, of course, not limited to three. 
         [0052]    According to an aspect of the invention, the contact portions of the plug receiving portion can easily be displaced in the lateral direction by virtue of torsion and elastic deformation of the rising portion and the elastic portion which connect together the soldering portion and the plug receiving portion. Thus, the lateral offset of the plug terminal relative to the plug receiving portion when the plug terminal is inserted into the plug receiving portion is absorbed. In addition, as viewed from the front, in the electric connector of the invention, since the rising portion and the elastic portion are entirely provided behind the plug receiving portion and nothing is provided on both the lateral external sides of the plug receiving portion, the overall width or lateral dimension of the electric connector can be narrowed. Then, a plurality of electric connectors like this are provided on a substrate in such a manner as to be aligned horizontally, the intervals at which they are so provided can be made small, and hence, the electric connector of the invention is suitable for the miniaturization of electronic equipment in this respect. In addition, since the plug receiving portion is formed into the substantially U-shape or substantially angular U-shape having the opening above the substrate, the electric connector of the invention is suitable for an electric connector into which a plug terminal is inserted into the substrate from above. 
         [0053]    According to an aspect of the invention, the lateral dimension of the electric connector can be narrowed. In addition, since the plug receiving portion is formed into the substantially U-shape or substantially angular U-shape having the opening in the parallel direction with the substrate, the electric connector of the invention is suitable for an electric connector into which a plug terminal is inserted in the parallel direction with the substrate. 
         [0054]    According to an aspect of the invention, since the second elastic portion is formed at the distal end of the elastic portion in such a manner as to be directed in parallel with the substrate and the plug receiving portion is formed at the distal end of the second elastic portion so formed, the portion that can be twisted and elastically deformed is made to be formed longer by the rising portion, the elastic portion and the second elastic portion, whereby the contact portions of the plug receiving portion can be displaced in the lateral direction more easily. 
         [0055]    According to an aspect of the invention, since the part of the elastic portion and the second elastic portion are bent into the substantially S-shape as viewed from the side thereof, the portion that can be twisted and elastically deformed is made to be formed longer, whereby the contact portions of the plug receiving portion can be displaced in the lateral direction more easily. 
         [0056]    According to an aspect of the invention, since the second elastic portion which is narrowed in the lateral direction is formed at the distal end of the elastic portion, the contact portions of the plug receiving portion can easily be displaced in the lateral direction by virtue of torsion and elastic deformation of the second elastic portion. 
         [0057]    According to an aspect of the invention, since the longitudinal slit is provided in the lateral center of the elastic portion so as to divide the elastic portion into the two elastic pieces, the elastic portion can be twisted and elastically deformed based on each of the elastic pieces, whereby the contact portions of the plug receiving portion can easily be displaced in the lateral direction. 
         [0058]    According to an aspect of the invention, since the longitudinal slit is provided in the lateral center of the portion which extends from the rising portion to the elastic portion so as to divide the portion into the two elastic pieces, the portions that can be twisted and elastically deformed are made longer by those elastic pieces, whereby the contact portion of the plug receiving portion can easily be displaced in the lateral direction. 
         [0059]    According to an aspect of the invention, since the elastic portion is formed by bending the sheet material at the upper end of the rising portion towards the soldering portion, the elastic portion lies at the end of the soldering portion, whereby the electric connector can be configured which has a small depth. 
         [0060]    According to an aspect of the invention, since the projecting portion which projects upwardly is formed at the other end of the soldering portion, the substantially U-shaped or substantially angular U-shaped bottom portion is brought into abutment with the projecting portion when the plug receiving portion is elastically displaced downwards, whereby the downward elastic deformation of the plug receiving portion is restricted, and there is no chance in which a plastic deformation is generated by the excessive elastic deformation. 
         [0061]    According to an aspect of the invention, since the projecting portion which projects upwardly is formed at the other end of the soldering portion, and the engagement portion is formed by extending the part of the distal end portion of the plug receiving portion towards the other end and bending the part so extended downwards, the engagement portion is brought into abutment with the projecting portion when the plug receiving portion is elastically displaced towards the one end of the soldering portion to thereby restrict the elastic displacement of the plug receiving portion towards the one end of the soldering portion, and there is no chance in which a plastic deformation is generated by the excessive elastic deformation. 
         [0062]    According to an aspect of the invention, since the restricting portions are provided in such a manner as to be brought into contact, respectively, with the outer surfaces of the plug receiving portion or to confront, respectively, the outer surfaces of the plug receiving portion with the space defined therebetween, the substantially U-shaped or substantially angular U-shaped opening of the plug receiving portion is restricted by the abutment of the plug receiving portion with the restricting portions, and there is no chance in which a plastic deformation is generated in the substantially U-shape or substantially angular U-shape of the plug receiving portion by the excessive elastic deformation. 
         [0063]    According to an aspect of the invention, since the extended portion is formed at the distal end of the elastic portion in such a manner as to extend towards the other end of the soldering portion in parallel with the substrate to reach above the soldering portion, and the projecting portion which projects upwardly is formed at the other end of the soldering portion, the extended portion is displaced downwards to be brought into abutment with the projecting portion when the plug receiving portion is elastically displaced downwards to thereby restrict the downward elastic displacement of the plug receiving portion is restricted. 
         [0064]    According to an aspect of the invention, since the extended portion is formed at the distal end of the elastic portion in such a manner as to extend towards the other end of the soldering portion in parallel with the substrate to reach above the soldering portion, the engagement portion is formed by extending further the part of the distal end portion of the extended portion and bending downwards the part so extended, and the projecting portion which projects upwardly is formed at the other end of the soldering portion, the engagement portion is displaced towards the one end of the soldering portion to be brought into abutment with the projecting portion when the plug receiving portion is elastically displaced towards the one end portion to thereby restrict the elastic displacement of the plug receiving portion towards the one end of the soldering portion.