Abstract:
A socket-side terminal includes: a root section that is fixed to a conductive wiring pattern on the main surface of a circuit wiring substrate by using solder; a rising section rising up from the root section and spaced apart from the main surface; an inverted U-shaped section one end of which is continuous with the top end of the rising section; a falling section that extends from the other end of the inverted U-shaped section towards the main surface; an inclined section that, as the inclined section extends from the bottom end of the falling section towards the main surface, is inclined with respect to the main surface to be spaced apart from the rising section; and an opposing section that is continuous with the bottom end of the inclined section, is positioned so as to be opposing the falling section, and is in contact with a header-side terminal.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to: a socket configured to electrically connect electronic components together; a connector comprising the socket; and a header used in the connector. 
       BACKGROUND ART 
       [0002]    Connectors have been conventionally used to electrically connect electronic components. A connector is such that electrical connection is established by bringing socket-side terminals provided to a socket and header-side terminals provided to a header into contact with each other. 
         [0003]    PTL 1 and PTL2 given below have been known as technical documents related to connectors. In the connectors of PTL1 and PTL2, a header and a socket are electrically connected together by fitting header-side terminals each forming a protrusion in a cross section into socket-side terminals each forming a recess portion in the cross section. 
       CITATION LIST 
     Patent Literature 
       [0004]    [PTL 1] Japanese Unexamined Patent Application Publication No. 2012-155928 
         [0005]    [PTL 2] Japanese Unexamined Patent Application Publication No. 2013-65541 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    In a conventional connector, the root portions of the socket-side terminals are fixed to a circuit board using solder. There is an increasingly strong demand for a further reduction in the width dimension of such a conventional connector. In order to meet the demand, distances between the root portions of the socket-side terminals and the other portions of the socket-side terminals need to be further shortened like the other parts of the connector need to be reduced in dimension. 
         [0007]    However, if the distances are further shortened, there is likelihood that when the root portions of the socket-side terminals are fixed to the circuit board using the solder, the solder adheres to portions of the socket-side terminals other than the root portions. If the solder adheres to inwardly-curving spring portions of the socket-side terminals, the spring performances of the socket-side terminals deteriorate. For this reason, a problem of difficulty in reducing the width dimension of the connector arises. 
         [0008]    The present invention has been proposed with the foregoing problem taken into consideration. An object of the present invention is to provide: a socket capable of preventing solder from adhering to portions of socket-side terminals other than root portions; a connector including the socket; and a header used in the connector. 
       Solution to Problem 
       [0009]    A socket of an embodiment of the present invention includes: a socket-side terminal configured to be electrically connected to a header-side terminal; and a socket housing to which the socket-side terminal is attached. The socket-side terminal includes: a root portion fixed to a conductor wiring pattern on a principal surface of a circuit board using solder; and a rising portion rising from the root portion, and extending to become away from the principal surface. The socket-side terminal further includes: an inverted U-shaped portion whose one end continues to an upper end of the rising portion; and a falling portion extending from an opposite end of the inverted U-shaped portion toward the principal surface. The socket-side terminal further includes an inclined portion inclined to the principal surface in such a way as to become farther away from the rising portion as extending from a lower end of the falling portion toward the principal surface. The socket-side terminal further includes a facing portion continuing to a lower end of the inclined portion, placed opposite the falling portion, and configured to be brought into contact with the header-side terminal. 
         [0010]    The inclined portion may be a flat portion extending along an inclined plane intersecting the principal surface at a predetermined angle. 
         [0011]    The angle of inclination of the inclined plane to the principal surface desirably has a value within a range of approximately 25° to approximately 65°. 
         [0012]    The inclined portion may be a curving portion projecting toward the solder. When it is assumed that there is an arc-shaped portion continuing to the falling portion and the facing portion, the curving portion is desirably placed farther away from the solder than the arc-shaped portion. 
         [0013]    The inclined portion may include at least one bending portion projecting toward the solder, and be formed from a combination of a plurality of flat portions continuing to each other via the at least one bending portion. When it is assumed that there is an arc-shaped portion continuing to the falling portion and the facing portion, the combination of the plurality of flat portions is desirably placed farther away from the solder than the arc-shaped portion. 
         [0014]    The inclined portion may be formed from a combination of differently-shaped portions including at least one flat portion and at least one curving portion, the combination projecting toward the solder. When it is assumed that there is an arc-shaped portion continuing to the falling portion and the facing portion, the combination of the differently-shaped portions is desirably placed farther away from the solder than the arc-shaped portion. 
         [0015]    The facing portion desirably includes a flat portion continuing to the inclined portion, and extending as becoming farther away from the falling portion. 
         [0016]    A distance between the rising portion and the falling portion is desirably equal to or less than a thickness of a base material of the socket-side terminal. 
         [0017]    A connector of an embodiment of the present invention includes: any one of the foregoing sockets; and a header including the header-side terminal configured to be electrically connected to the socket-side terminal. The header-side terminal is inserted between and held by the inverted U-shaped portion and the facing portion. 
         [0018]    It is desirable that: the socket-side terminal include a locking portion; and the header-side terminal include a locked portion configured to be locked to the locking portion. 
         [0019]    A header of an embodiment of the present invention is used in the connector. 
       Advantageous Effects of Invention 
       [0020]    The present invention makes possible to prevent the solder from adhering to the portion of the socket-side terminal other than the root portion despite a reduction in the width dimension of the connector. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]      FIG. 1  is a first perspective view of a header of an embodiment of the present invention. 
           [0022]      FIG. 2  is a second perspective view of the header of the embodiment of the present invention. 
           [0023]      FIG. 3  is a first perspective view of a socket of the embodiment of the present invention. 
           [0024]      FIG. 4  is a second perspective view of the socket of the embodiment of the present invention. 
           [0025]      FIG. 5  is a diagram including: a cross-sectional view of the header taken along the V-V line of  FIGS. 1 and 2 ; and a cross-sectional view of the socket taken along the V-V line of  FIGS. 3 and 4 .  FIG. 5  is the diagram showing how the header and the socket of the embodiment of the present invention look immediately before the header and the socket are fitted together. 
           [0026]      FIG. 6  is a diagram including: the cross-sectional view of the header taken along the V-V line of  FIGS. 1 and 2 ; and the cross-sectional view of the socket taken along the V-V line of  FIGS. 3 and 4 .  FIG. 5  is the diagram showing how the header and the socket of the embodiment of the present invention look while the header and the socket are fitted together. 
           [0027]      FIG. 7  is a cross-sectional view of the socket and a circuit board for comparing socket-side terminals of the embodiment of the present invention and socket-side terminals of a first comparative example. 
           [0028]      FIG. 8  is a cross-sectional view of the socket and the circuit board for comparing the socket-side terminals of the embodiment of the present invention and socket-side terminals of a second comparative example. 
           [0029]      FIG. 9  is a front view of a socket-side terminal of a first example of the embodiment of the present invention. 
           [0030]      FIG. 10  is a front view of a socket-side terminal of a second example of the embodiment of the present invention. 
           [0031]      FIG. 11  is a front view of a socket-side terminal of a third example of the embodiment of the present invention. 
           [0032]      FIG. 12  is a front view of a socket-side terminal of a comparative example of the embodiment of the present invention. 
           [0033]      FIG. 13  is a diagram showing inclined portions of socket-side terminals of first, fourth, fifth and sixth examples of the embodiment of the present invention, and an arc-shaped portion of the socket-side terminal of the comparative example, for comparison purposes. 
           [0034]      FIG. 14  is a diagram including: a cross-sectional view of the header taken along the XIV-XIV line of  FIGS. 1 and 2 ; and a cross-sectional view of the socket taken along the XIV-XIV line of  FIGS. 3 and 4 .  FIG. 5  is the diagram showing how the header and the socket of the embodiment of the present invention look immediately before the header and the socket are fitted together. 
           [0035]      FIG. 15  is a diagram including: the cross-sectional view of the header taken along the XIV-XIV line of  FIGS. 1 and 2 ; and the cross-sectional view of the socket taken along the XIV-XIV line of  FIGS. 3 and 4 .  FIG. 5  is the diagram showing how the header and the socket of the embodiment of the present invention look while the header and the socket are fitted together. 
           [0036]      FIG. 16  is a front view of a header of a different example of the embodiment of the present invention. 
           [0037]      FIG. 17  is a plan view of the header of the different example of the embodiment of the present invention. 
           [0038]      FIG. 18  is a bottom view of the header of the different example of the embodiment of the present invention. 
           [0039]      FIG. 19  is a side view of the header of the different example of the embodiment of the present invention. 
           [0040]      FIG. 20  is a first perspective view of a header-side terminal of the embodiment of the present invention. 
           [0041]      FIG. 21  is a second perspective view of the header-side terminal of the embodiment of the present invention. 
           [0042]      FIG. 22  is a third perspective view of the header-side terminal of the embodiment of the present invention. 
           [0043]      FIG. 23  is a fourth perspective view of the header-side terminal of the embodiment of the present invention. 
           [0044]      FIG. 24  is a front view of the header-side terminal of the embodiment of the present invention. 
           [0045]      FIG. 25  is a plan view of the header-side terminal of the embodiment of the present invention. 
           [0046]      FIG. 26  is a bottom view of the header-side terminal of the embodiment of the present invention. 
           [0047]      FIG. 27  is a left side view of the header-side terminal (an inside of the header) of the embodiment of the present invention. 
           [0048]      FIG. 28  is a right side view of the header-side terminal (an outside of the header) of the embodiment of the present invention. 
           [0049]      FIG. 29  is a front view of a socket of a different example of the embodiment of the present invention. 
           [0050]      FIG. 30  is a plan view of the socket of the different example of the embodiment of the present invention. 
           [0051]      FIG. 31  is a bottom view of the socket of the different example of the embodiment of the present invention. 
           [0052]      FIG. 32  is a side view of the socket of the different example of the embodiment of the present invention. 
           [0053]      FIG. 33  is a first perspective view of the socket of the different example of the embodiment of the present invention. 
           [0054]      FIG. 34  is a second perspective view of the socket of the different example of the embodiment of the present invention. 
           [0055]      FIG. 35  is a diagram for explaining: a relationship between a pitch between header-side terminals and a pitch between a header-side terminal and a corresponding header-side retaining fitting in the header of the different example of the embodiment of the present invention; and a relationship between an interval between locked portions of mutually-facing header-side terminals and an interval between locked portions of mutually-facing header-side retaining fittings in the header of the different example of the embodiment of the present invention. 
           [0056]      FIG. 36  is a diagram for explaining: a relationship between a pitch between socket-side terminals and a pitch between a socket-side terminal and a corresponding socket-side retaining fitting in the socket of the different example of the embodiment of the present invention; and a relationship between an interval between locking piece portions of mutually-facing socket-side terminals and an interval between locking piece portions of mutually-facing socket-side retaining fittings in the socket of the different example of the embodiment of the present invention. 
           [0057]      FIG. 37  is a first perspective view of the socket-side terminal of the embodiment of the present invention. 
           [0058]      FIG. 38  is a second perspective view of the socket-side terminal of the embodiment of the present invention. 
           [0059]      FIG. 39  is a third perspective view of the socket-side terminal of the embodiment of the present invention. 
           [0060]      FIG. 40  is a fourth perspective view of the socket-side terminal of the embodiment of the present invention. 
           [0061]      FIG. 41  is a front view of the socket-side terminal of the embodiment of the present invention. 
           [0062]      FIG. 42  is a plan view of the socket-side terminal of the embodiment of the present invention. 
           [0063]      FIG. 43  is a bottom view of the header-side terminal of the embodiment of the present invention. 
           [0064]      FIG. 44  is a left side view of the socket-side terminal (an outside of the socket) of the embodiment of the present invention. 
           [0065]      FIG. 45  is a right side view of the socket-side terminal (an inside of the socket) of the embodiment of the present invention. 
           [0066]      FIG. 46  is a first perspective view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0067]      FIG. 47  is a second perspective view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0068]      FIG. 48  is a third perspective view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0069]      FIG. 49  is a fourth perspective view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0070]      FIG. 50  is a front view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0071]      FIG. 51  is a plan view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0072]      FIG. 52  is a bottom view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0073]      FIG. 53  is a back view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0074]      FIG. 54  is a side view of the socket-side retaining fitting of the embodiment of the present invention. 
           [0075]      FIG. 55  is a first perspective view of a socket-side terminal of a different example of the embodiment of the present invention. 
           [0076]      FIG. 56  is a second perspective view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0077]      FIG. 57  is a third perspective view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0078]      FIG. 58  is a fourth perspective view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0079]      FIG. 59  is a front view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0080]      FIG. 60  is a plan view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0081]      FIG. 61  is a bottom view of the socket-side terminal of the different example of the embodiment of the present invention. 
           [0082]      FIG. 62  is a left side view of the socket-side terminal (an outside of the socket) of the different example of the embodiment of the present invention. 
           [0083]      FIG. 63  is a right side view of the socket-side terminal (an inside of the socket) of the different example of the embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0084]    Referring to the drawings, descriptions will be hereinbelow provided for a socket, a connector using the socket, and a header used in the connector of an embodiment of the present invention. 
         [0085]    The connector of the embodiment is designed to be used to electrically connect circuit boards together in an electronic device as a mobile terminal device such as a smartphone. Note that, the connector of the present invention may be used to electrically connect any components together as long as the connector is used in the electronic device. 
         [0086]    The connector of the embodiment includes a header and a socket. The header is a component designed to be electrically connected to a conductor wiring pattern on a certain circuit board, or a printed circuit board, in the electronic device. The socket is a component designed to be electrically connected to a conductor wiring pattern on another circuit board. Incidentally, the header and the socket may be electrically connected to FPCs (Flexible Printed Circuits). 
         [0087]    Referring to  FIGS. 1 and 2 , descriptions will be provided for a header  1  included in the connector of the embodiment of the present invention. 
         [0088]    The header  1  includes: metal-made header-side terminals  10  each called a post; metal-made header-side retaining fittings  20 ; and a resin-made header housing  30 . A specified part of each header-side terminal  10  is exposed to the outside. The other part of the header-side terminal  10  is attached to the header housing  30  by insert molding. With regard to each header-side retaining fitting  20 , too, its specified part is exposed to the outside, and its other part is attached to the header housing  30  by insert molding. 
         [0089]    With regard to dimensions of the header  1 , its width W 1  and length L 1  shown in  FIG. 1  are 1.50 mm and 5.15 mm, respectively. The pitch P 1  between each two of the header-side terminals  10  shown in  FIG. 1  is 0.35 mm. Hereinafter, a direction specified by the width W 1  shown in  FIG. 1  will be referred to as a “width direction” of the header, and a direction specified by the length L 1  shown in  FIG. 1  will be referred to as a “lengthwise direction” of the header. 
         [0090]    The header housing  30  is produced by resin molding, and is an electrically-insulated component. As shown in  FIGS. 1 and 2 , the header housing  30  has an external shape with all the surfaces of it shaped almost like a rectangular plate. That is to say, the external shape of the header housing  30  is an almost rectangular parallelepiped. A recessed portion is formed in a central portion of one principal surface of the header housing  30 . The recessed portion in the central portion is formed from a bottom surface portion  30   a , two edge portions  30   b  and two edge portions  30   c . The two edge portions  30   b  each extend in the lengthwise direction of the header  1 , or in a long-side direction of the rectangle, and both face each other. The two edge portions  30   c  each extend in the width direction of the header  1 , or in a short-side direction of the rectangle, and both face each other. The recessed portion in the central portion forms a space shaped almost like a rectangular parallelepiped which is slightly smaller than the external shape of the header housing  30  shaped almost like a rectangular parallelepiped. Recessed portions  30   d  are formed in each edge portion  30   c.    
         [0091]    Each header-side terminal  10  is produced by metal forming, and is a conductive component. As described later, one end of the header-side terminal  10  is designed to be connected to a conductor wiring pattern on a circuit board. 
         [0092]    As shown in  FIGS. 1 and 2 , each header-side terminal  10  extends from a predetermined position on an outer surface of the corresponding edge portion  30   b  to a tip end portion of the edge portion  30   b , and curves along the surface of the tip end portion of the edge portion  30   b . Furthermore, the header-side terminal  10  extends along an inner surface of the edge portion  30   b  from the tip end portion of the edge portion  30   b  to a joining portion where the bottom surface portion  30   a  and the edge portion  30   b  are joined together. In addition, the header-side terminal  10  penetrates the joining portion while curving. Moreover, after penetrating the joining portion, the header-side terminal  10  projects from the front surface (or rear surface) of the header housing  30 . Detailed description will be provided for the shape of the header-side terminal  10  later. 
         [0093]    The header-side retaining fitting  20  are each made of the same metal as the header-side terminals  10  are. Note that, because the header-side retaining fitting  20  are used to be connected to socket-side retaining fittings  50 , the header-side retaining fitting  20  are made of the metal from a viewpoint of strength of their material, but not from a viewpoint of their function as conductive components. As shown in  FIGS. 1 and 2 , the header-side retaining fitting  20  have the same shape as the header-side terminals  10  do. To put it concretely, each header-side retaining fitting  20  extends from a predetermined position on an outer surface of a corresponding edge portion  30   e , whose shape is similar to those of the edge portions  30   b , to a tip end portion of the edge portion  30   e , and curves along the surface of the tip end portion of the edge portion  30   e . Furthermore, the header-side retaining fitting  20  extends along an inner surface of the edge portion  30   e  from the tip end portion of the edge portion  30   e  to a joining portion where the bottom surface portion  30   a  and the edge portion  30   e  are joined together. In addition, the header-side retaining fitting  20  penetrates the joining portion while curving. Moreover, after penetrating the joining portion, the header-side retaining fitting  20  projects from the front surface (or rear surface) of the header housing  30 . Detailed description will be provided for the shape of the header-side retaining fitting  20  later. 
         [0094]    Both the header-side terminals  10  and the header-side retaining fittings  20  are each formed by curving a metal-made plate material as a base material. 
         [0095]    Next, referring to  FIGS. 3 and 4 , descriptions will be provided for a socket  2  included in the connector of the embodiment of the present invention. 
         [0096]    As shown in  FIGS. 3 and 4 , the socket  2  includes: metal-made socket-side terminals  40  each called a contact; the metal-made socket-side retaining fittings  50 ; and a resin-made socket housing  60 . A specified part of each socket-side terminal  40  is exposed to the outside, while the other part of the socket-side terminal  40  is attached to the socket housing  60  by insert molding. With regard to each socket-side retaining fitting  50 , too, its specified part is exposed to the outside, and its other part is attached to the socket housing  60  by insert molding. 
         [0097]    With regard to dimensions of the socket  2 , its width W 2  and length L 2  shown in  FIG. 3  are 1.70 mm and 5.85 mm, respectively. The pitch P 2  between each two of the socket-side terminals  40  shown in  FIG. 3  is 0.35 mm. Hereinafter, a direction specified by the width W 2  shown in  FIG. 3  will be referred to as a “width direction” of the socket, and a direction specified by the length L 2  shown in  FIG. 3  will be referred to as a “lengthwise direction” of the socket. 
         [0098]    The socket housing  60  is produced by resin molding, and is an electrically-insulated component. As shown in  FIGS. 3 and 4 , the socket housing  60  has an external shape with all the surfaces of it shaped almost like a rectangular plate. That is to say, the external shape of the socket housing  60  is an almost rectangular parallelepiped. The socket housing  60  includes a frame-shaped space  60   a  extending along the four sides of the rectangle of the socket housing  60 . The frame-shaped space  60   a  is surrounded by two edge portions  60   c  and two edge portions  60   d . The two edge portions  60   c  each extend in the lengthwise direction of the socket, or in a long-side direction of the rectangle, and both face each other. The two edge portions  60   d  each extend in the width direction of the socket, or in a short-side direction of the rectangle, and both face each other. The frame-shaped space  60   a  surrounds an island portion  60   b  positioned at the center of the frame-shaped space  60   a , and shaped almost like a rectangular parallelepiped. The island portion  60   b  is provided with cut portions  60   b   1 . In addition, the edge portions  60   c  are provided with cut portions  60   c   1 . The cut portions  60   b   1  and the cut portions  60   c   1  continue to cut portions  60   f  in the bottom surface of the socket  2 . 
         [0099]    Each socket-side terminal  40  is produced by metal forming, and is a conductive component. The socket-side terminal  40  is provided extending from the cut portions  60   b   1 , the frame-shaped space  60   a , and the cut portion  60   f  to the cut portion  60   c   1 . Furthermore, the socket-side terminal  40  projects from the corresponding edge portion  60   c . Detailed description will be provided for the shape of the socket-side terminal  40  later. 
         [0100]    The socket-side retaining fittings  50  are attached in order for part of each socket-side retaining fitting  50  to increase the strength of the socket housing  60 . The socket-side retaining fittings  50  are made of metal. Incidentally, the socket-side retaining fittings  50  and the socket-side terminals  40  may be made from the same material. Note that, the socket-side retaining fittings  50  are made of metal from a viewpoint of the strength, but not from a viewpoint of the conductive material. Each socket-side retaining fitting  50  covers the corresponding side surface of the socket housing  60  extending in the width direction of the socket  2 . Furthermore, the socket-side retaining fitting  50  partially covers the front surface and rear surface of the socket housing  60  which extend in the lengthwise direction of the socket  2 . Parts of the socket-side retaining fitting  50  penetrate the respective edge portions  60   c  of the socket housing  60 . To put it concretely, the parts of the socket-side retaining fitting  50  penetrate parts of the socket housing  60 , which are under corresponding covering portions  60   e , from the outside toward the inside to project toward the frame-shaped space  60   a . Detailed descriptions will be provided for the shape of the socket-side retaining fitting  50  later. 
         [0101]    It should be noted that both the socket-side terminals  40  and the socket-side retaining fittings  50  are each formed by curving a metal-made plate material as a base material. 
         [0102]    Next, referring to  FIGS. 5 and 6 , detailed descriptions will be provided for the header  1  and the socket  2  in a connector  120  of the embodiment. In  FIGS. 5 and 6 , the header  1  and the socket  2  of the embodiment are fixed to a circuit board  70 . However, the header and the socket of the present invention include ones which have not been fixed to the circuit board yet. Incidentally, when the header  1  and the socket  2  shown in  FIG. 6  are fitted to each other, the thickness T of the connector  120  is 0.60 mm. Hereinafter, a direction specified by the thickness T in  FIG. 6  will be referred to as a “thickness direction” of the connector. 
         [0103]      FIGS. 5 and 6  show the header  1  fixed to a conductor wiring pattern  75  on a circuit board  70  using solder  80 . Note that, as described above, the header  1  may be electrically connected to the FPC (Flexible Printed Circuit). 
         [0104]    As learned from a cross-sectional view of the header  1  shown in  FIG. 5 , two header-side terminals  10  having the same shape are attached to the header housing  30  while facing each other. Meanwhile, as learned from a cross-sectional view of the socket  2  shown in  FIG. 5 , two socket-side terminals  40  having the same shape are similarly attached to the socket housing  60  while facing each other. Once the header  1  is fitted into the socket  2 , the conductive header-side terminals  10  come into contact with the conductive socket-side terminals  40 , as shown in  FIG. 6 . This creates a state in which electricity flows between the header-side terminals  10  and the socket-side terminals  40 . In other words, the header  1  and the socket  2  are electrically connected together. 
         [0105]    Next, referring to  FIGS. 5 and 6 , descriptions will be provided for the header-side terminals  10 . 
         [0106]    Each header-side terminal  10  includes a protrusion  10   a  projecting from the front surface or rear surface (in  FIGS. 5 and 6 , a side surface) of the header housing  30 . The protrusion  10   a  is fixed to the conductor wiring pattern  175  on the circuit board  170  using the solder  180 . Note that, the header of the present invention includes the protrusion  10   a  which, albeit currently not fixed to any member, is designed to be fixed to the conductor wiring pattern  175 . As learned from  FIG. 5 , the upper surface of the protrusion  10   a  extends in parallel with the upper surface of the header housing  30 , or the outer surface of the bottom surface portion  30   a.    
         [0107]    The header-side terminal  10  includes an inner side portion  10   b  continuing to the protrusion  10   a . The inner side portion  10   b  penetrates, while curving, the joining portion where the bottom surface portion  30   a  and the edge portion  30   b  of the header housing  30  are joined together. The inner side portion  10   b  subsequently extends along the inner surface of the edge portion  30   b  to the tip end portion of the edge portion  30   b.    
         [0108]    The header-side terminal  10  includes a V-shaped groove  10   c , or a V-shaped notch, formed in the inner side surface of the inner side portion  10   b . An arc-shaped protrusion  40   k , which is described later, of the socket-side terminal  40  is fitted into the V-shaped groove  10   c.    
         [0109]    The header-side terminal  10  includes a tip end portion  10   d  continuing to one end of the inner side portion  10   b . The tip end portion  10   d  curves along the shape of the tip end of the edge portion  30   b  of the header housing  30 . 
         [0110]    The header-side terminal  10  includes a locked portion  10   e  continuing to the tip end portion  10   d . As learned from comparison between  FIGS. 5 and 6 , once the header-side terminal  10  is fitted into the socket-side terminal  40 , the locked portion  10   e  is inserted deeper than a locking portion  40   d  as a step portion. For this reason, when the header-side terminal  10  is pulled out of the socket-side terminal  40 , the locked portion  10   e  comes into contact with the locking portion  40   d . In other words, the locked portion  10   e  of the header-side terminal  10  is locked by the locking portion  40   d  of the socket-side terminal  40 . Thereby, the header-side terminal  10  is inhibited from being pulled out of the socket-side terminal  40 . To put it concretely, the header-side terminal  10  cannot be pulled out of the socket-side terminal  40  by mere application of external force less than a predetermined value. On the other hand, the header-side terminal  10  can be pulled out of the socket-side terminal  40  by application of external force equal to or greater than the predetermined value. In other words, the locked portion  10   e  of the header-side terminal  10  and the locking portion  40   d  of the socket-side terminal  40  form a lock mechanism in which the locked portion  10   e  and the locking portion  40   d  can be unlocked from each other by the application of external force equal to or greater than the predetermined value. 
         [0111]    The header-side terminal  10  further includes an outer side portion  10   f  continuing to the tip end portion  10   d  via the locked portion  10   e , and extending along the outer surface of the edge portion  30   b.    
         [0112]    Next, referring to  FIGS. 5 and 6 , descriptions will be provided for the socket-side terminals  40 . 
         [0113]    Each socket-side terminal  40  includes a root portion  40   a  projecting from the front surface or rear surface (in  FIGS. 5 and 6 , a side surface) of the socket housing  60 . The root portion  40   a  is fixed to a conductor wiring pattern  75  on the circuit board  70  using solder  80 . Note that, the socket of the present invention includes the root portion  40   a  which, albeit currently not fixed to any member, is designed to be fixed to the conductor wiring pattern  75 . The lower surface of the root portion  40   a  extends along a principal surface M of the circuit board  70 , and is placed on the same plane as the bottom surface of the socket housing  60  is. 
         [0114]    The socket-side terminal  40  includes a rising portion  40   b  rising from the root portion  40   a , and extending to become away from the circuit board  70 . After curving from the root portion  40   a , the rising portion  40   b  enters the cut portion  60   c   1 , and extends along the inner surface of the edge portion  60   c.    
         [0115]    The socket-side terminal  40  includes an inverted U-shaped portion  40   c  whose one end continues to the upper end of the rising portion  40   b . The inverted U-shaped portion  40   c  is shaped like the upside-down-placed letter U. 
         [0116]    The socket-side terminal  40  includes the locking portion  40   d  continuing to the opposite end of the inverted U-shaped portion  40   c . As described above, the locking portion  40   d  functions as the component configured to inhibit the movement of the locked portion  10   e  when the header-side terminal  10  is to be pulled out of the socket-side terminal  40 . In other words, the locking portion  40   d  of the socket-side terminal  40  can lock the locked portion  10   e  of the header-side terminal  10  by coming into contact with the locked portion  10   e . The locking portion  40   d  of the socket-side terminal  40  and the locked portion  10   e  of the header-side terminal  10  form the lock mechanism in which the lock can be unlocked from each other by the application of external force equal to or greater than the predetermined value. 
         [0117]    The locking portion  40   d  may be produced by rolling a base material which makes parts of the socket-side terminal  40  different from each other in terms of thickness. Otherwise, the locking portion  40   d  may be produced by bending the base material of the socket-side terminal  40  in the thickness direction. 
         [0118]    The socket-side terminal  40  includes a falling portion  40   e  continuing to the locking portion  40   d , and extending almost in parallel with the rising portion  40   b.    
         [0119]    The socket-side terminal  40  includes an inclined portion  40   f  continuing to the lower end of the falling portion  40   e . The inclined portion  40   f  is inclined to the principal surface M of the circuit board  70  in such a way as to become farther from the rising portion  40   b  as extending toward the principal surface M from the lower end of the falling portion  40   e . To put it concretely, the inclined portion  40   f  extends along an inclined plane S which intersects the principal surface M of the circuit board  70  at a predetermined angle. Thus, the inclined portion  40   f  is placed away from the solder  80  by a predetermined distance. 
         [0120]    As shown in  FIG. 6 , the socket-side terminal  40  includes a facing portion  40   z  continuing to the inclined portion  40   f . The facing portion  40   z  includes a flat portion  40   g , a first oblique portion  40   h , an arc-shaped portion  40   i , a second oblique portion  40   j , the arc-shaped protrusion  40   k , and a tip end portion  40   l , which will be described below. Concretely, the facing portion  40   z  is as follows. 
         [0121]    The facing portion  40   z  includes the flat portion  40   g  continuing to the lower end of the inclined portion  40   f . As shown in  FIG. 5 , the flat portion  40   g  extends along the principal surface M of the circuit board  70  in such a way as to become farther from the falling portion  40   e . The flat portion  40   g , however, does not have to be in parallel with the principal surface M. The flat portion  40   g  is provided in order to increase the length of a spring portion, which will be described later. 
         [0122]    As shown in  FIG. 6 , the facing portion  40   z  includes the first oblique portion  40   h  continuing to the flat portion  40   g , and extending in a direction inclined to the principal surface M of the circuit board  70 . The first oblique portion  40   h  extends in such a way as to become farther from the falling portion  40   e  as becoming farther from the circuit board  70 . The first oblique portion  40   h  continues to the arc-shaped portion  40   i . The arc-shaped portion  40   i  is a curving portion projecting in such a way as to become farther from the falling portion  40   e . The arc-shaped portion  40   i  continues to the second oblique portion  40   j  extending in a direction inclined to the principal surface M of the circuit board  70 . The second oblique portion  40   j  extends in such a way as to become closer to the falling portion  40   e  as becoming farther from the circuit board  70 . Thus, the second oblique portion  40   j  is placed above the first oblique portion  40   h.    
         [0123]    As shown in  FIG. 6 , the facing portion  40   z  includes the arc-shaped protrusion  40   k  whose one end continues to the upper end of the second oblique portion  40   j . As shown in  FIG. 6 , the arc-shaped protrusion  40   k  is fitted into the V-shaped groove  10   c  of the header-side terminal  10 . The opposite end of the arc-shaped protrusion  40   k  continues to the tip end portion  40   l . The tip end portion  40   l  extends almost in parallel with the second oblique portion  40   j . As learned from  FIGS. 5 and 6 , the facing portion  40   z  ( 40   g ,  40   h ,  40   i ,  40   j ,  40   k ,  40   l ) continues to the inclined portion  40   f , and as a whole, faces the falling portion  40   e.    
         [0124]    In the embodiment, when the header  1  and the socket  2  are fitted together, the header-side terminal  10  is inserted between the inverted U-shaped portion  40   c  and the arc-shaped protrusion  40   k , as shown in  FIG. 6 . At this time, the falling portion  40   e , the inclined portion  40   f , the flat portion  40   g , the first oblique portion  40   h , the arc-shaped portion  40   i , the second oblique portion  40   j , the arc-shaped protrusion  40   k  and the tip end portion  40   l  integrally function as the spring portion. The spring portion ( 40   e ,  40   f ,  40   g ,  40   h ,  40   i ,  40   j ,  40   k ,  40   l ) is elastically deformed, once the projecting portion of the header-side terminal  10  is inserted into the recessed portion of the socket-side terminal  40 . Thus, the distance between the arc-shaped protrusion  40   k  and the two portions including the falling portion  40   e  and the inverted U-shaped portion  40   c  becomes longer. At this time, the locked portion  10   e  of the header-side terminal  10  is inserted lower than the locking portion  40   d  of the socket-side terminal  40 . Thereby, the arc-shaped protrusion  40   k  of the socket-side terminal  40  is fitted into the V-shaped groove  10   c  of the header-side terminal  10 . 
         [0125]    While the header-side terminal  10  is being fitted in the socket-side terminal  40 , the elastically-deformed spring portion produces resilience. This resilience makes the arc-shaped protrusion  40   k  press the header-side terminal  10  against each of the falling portion  40   e  and the inverted U-shaped portion  40   c . Thereby, the header-side terminal  10  is held by the socket-side terminal  40 . At this time, the header-side terminal  10  comes into contact with each of the falling portion  40   e  and the arc-shaped protrusion  40   k.    
         [0126]    To put it concretely, as shown in  FIG. 6 , the outer side portion  10   f  of the header-side terminal  10  comes into contact with the inverted U-shaped portion  40   c  of the socket-side terminal  40  at a contact point C 1 . The tip end portion  10   d  of the header-side terminal  10  comes into contact with the falling portion  40   e  of the socket-side terminal  40  at a contact point C 2 . In addition, the V-shaped groove  10   c  of the header-side terminal  10  comes into contact with the arc-shaped protrusion  40   k  of the socket-side terminal  40  at a contact point C 3 . In sum, the header-side terminal  10  comes into contact with the socket-side terminal  40  at the plurality of contact points. For this reason, the electrical connection between the header-side terminal  10  and the socket-side terminal  40  is highly reliable. Incidentally, the elastic deformation of the spring portion may make the boundary portion between the flat portion  40   g  and the first oblique portion  40   h  come into contact with the circuit board  70  at a contact point C 4  in addition to the contact points C 1 , C 2 , and C 3 . 
         [0127]    The header-side terminal  10  and the socket-side terminal  40  of the embodiment come into contact with each other at the plurality of contact points. Instead, however, the header-side terminal and the socket-side terminal of the present invention may be configured to come into contact with each other at a single contact point between the inner side surface of the header-side terminal and the facing portion of the socket-side terminal. 
         [0128]    Next, using  FIG. 7 , the inclined portion of the embodiment of the present invention will be compared with an arc-shaped portion R of a comparative example  40   f.    
         [0129]    As described above, in the socket  2  of the embodiment, the inclined portion  40   f  represented by solid lines in  FIG. 7  continues to each of the falling portion  40   e  and the flat portion  40   g . On the other hand, in a socket of the comparative example, instead of the inclined portion  40   f , the arc-shaped portion R represented by imaginary lines in  FIG. 7  continues to each of the falling portion  40   e  and the flat portion  40   g . The comparison between the inclined portion  40   f  and the arc-shaped portion R shows that a distance d 2  between the inclined portion  40   f  of the embodiment and the solder  80  is greater than a distance d 1  between the arc-shaped portion R of the comparative example and the solder  80 . For this reason, the inclined portion  40   f  of the embodiment makes the solder  80 , while melt, less likely to adhere to the portions of the socket-side terminal  40  except for the root portion  40   a  than the arc-shaped portion R of the comparative example. As a result, even if a distance d 4  between the rising portion  40   b  and the falling portion  40   e  is decreased, or even if a distance d 3  between the outer side surface of the rising portion  40   b  and the inner side surface of the inverted U-shaped portion  40   c , the solder  80 , while melt, is less likely to adhere to the inclined portion  40   f . Accordingly, the inclined portion  40   f  of the embodiment reduces the likelihood that the function of the spring portion ( 40   e ,  40   f ,  40   g ,  40   h ,  40   i ,  40   j ,  40   k ,  40   l ) deteriorates due to the adhering of the solder  80 . 
         [0130]    As learned from the above, the inclined portion  40   f  of the embodiment can make a width dimension W 2  (the width dimension W 2  in  FIGS. 3 and 6 ) or a dimension d 5  (see  FIG. 7 ) of the socket smaller than the arc-shaped portion R does. For this reason, the width dimension of the connector  120  can be reduced. 
         [0131]    In the socket-side terminal  40  of the embodiment, the distance d 3  between the outer side surface of the rising portion  40   b  and the inner side surface of the falling portion  40   e  is less than the thickness of the base material of the socket-side terminal  40 . In other words, the width of a gap dx is less than both a thickness t 1  of the one end and a thickness t 2  of the opposite end of the inverted U-shaped portion  40   c . The thickness of the base material means the thickness of the plate-shaped material before processing the socket-side terminal  40  from the plate-shaped material. 
         [0132]    The following should be noted. If as shown in  FIG. 8 , a long inclined portion  40   x  were provided to the socket-side terminal  40 , the distance d 2  between the inclined portion  40   x  and the solder  80  would be able to be increased very much. However, the falling portion  40   e  and the flat portion  40   g  would be shortened very much. For this reason, the spring length of the spring portion ( 40   e ,  40   f ,  40   g ,  40   h ,  40   i ,  40   j ,  40   k ,  40   l ) would be decreased. Furthermore, the space which receives the header-side terminal  10  would become smaller. 
         [0133]    It is desirable that the inclined portion  40   f  be formed from a flat portion forming a part interposed between the two parallel flat surfaces. The reason for this is that when the inclined portion  40   f  is such a flat portion, the structure of the inclined portion  40   f  can be simplified, and the distance d 2  between the inclined portion  40   f  and the solder  80  can be increased as much as possible. 
         [0134]    It is desirable that as shown in  FIGS. 9 to 11 , an angle of inclination of an inclined plane S of the inclined portion  40   f  of the embodiment to the principal surface M of the circuit board  70  be within a range of approximately 25° to approximately 65°. The reason for this is that the distance from the solder  80  to the inclined portion  40   f  can be made greater than the distance from the solder  80  to the arc-shaped portion R (see  FIG. 7 ) of the comparative example shown in  FIG. 12 . More detailed descriptions will be provided for this as follows. 
         [0135]    Reference sign K denotes the distance from the inner side surface of the rising portion  40   b  to the inclined plane S (or a corresponding part of the arc-shaped portion R) at a position at the height of H=0.10 mm above the principal surface M of the circuit board  70 , that is to say, at a position of the upper surface of the thickness of a generally-used solder mask. The distances K in the cases of the inclined portions  40   f  shown in  FIGS. 9 to 11  is compared with the distance K in the case of the arc-shaped portion R shown in  FIG. 12 . Incidentally, the positions of points O shown in  FIGS. 9  to  11  represent the position of a start point O of the arc of the arc-shaped portion R shown in  FIG. 12 . 
         [0136]      FIG. 9  is a diagram showing the socket-side terminal  40  which makes an angle X of the inclined plane S to the principal surface M of the circuit board  70  equal to 45°. The distance K in the case of the inclined portion  40   f  shown in  FIG. 9  is 0.095 mm, and is greater than 0.076 mm which is the distance K in the case of the arc-shaped portion R of the comparative example shown in  FIG. 12 . 
         [0137]      FIG. 10  is a diagram showing the socket-side terminal  40  which makes the angle X of the inclined plane S to the principal surface M of the circuit board  70  equal to 25°. The distance K in the case of the inclined portion  40   f  shown in  FIG. 10  is 0.100 mm, and is greater than 0.076 mm which is the distance K in the case of the arc-shaped portion R of the comparative example shown in  FIG. 12 . 
         [0138]      FIG. 11  is a diagram showing the socket-side terminal  40  which makes the angle X of the inclined plane S to the principal surface M of the circuit board  70  equal to 65°. The distance K in the case of the inclined portion  40   f  shown in  FIG. 11  is 0.079 mm, and is greater than 0.076 mm which is the distance K in the case of the arc-shaped portion R of the comparative example shown in  FIG. 12 . 
         [0139]    As learned from the above, when the angles X shown in  FIGS. 9 to 11  are increased too much, the distances K in the case of the inclined portions  40   f  become smaller than the distance K in the case of the arc-shaped portion R, and therefore, the solder  80  is more likely to adhere to the inclined portions  40   f . As a result, the distance d 3  between the outer side surface of the rising portion  40   b  and the inner side surface of the falling portion  40   e  (see  FIG. 7 ) cannot be decreased, and therefore, the width dimension W 2  of the socket-side terminal  40  (see  FIGS. 3 and 6 ) cannot be decreased. For this reason, it is desirable that the angle X be not greater than 65°. On the other hand, when the angle X is reduced too much, the width dimension of the socket-side terminal  40  becomes larger. In this case, too, the width dimension W 2  of the socket-side terminal  40  (see  FIGS. 3 and 6 ) cannot be reduced. For this reason, it is desirable that the angle X be not less than approximately 25°. Note that, if the width dimension W 2  of the socket-side terminal  40  (see  FIGS. 3 and 6 ) can be reduced, the angle X may be out of the range of 25° to 65°. 
         [0140]    Referring to the  FIG. 13 , descriptions will be provided for inclined portions of the present invention which are not the inclined portions  40   f  of the embodiment. To this end, the arc-shaped portion R of the comparative example which continues to the falling portion  40   e  and the flat portion  40   g  is considered. It is supposed that the arc-shaped portion R of the comparative example is inclined from the falling portion  40   e  through the arc-shaped portion R to the flat portion  40   g , that is to say, the tangent of the arc-shaped portion R continuously changes. 
         [0141]    The inclined portions  40   f  shown in  FIGS. 9 to 11  are the flat portions extending from the lower end of the falling portion  40   e  along the inclined plane S. Note that, the inclined portion of the present invention may take on any shape, as long as the inclined portion as a whole extends along the inclined plane S to the principal surface M. In other words, as long as the start point and end point of the inclined plane S lie in the inclined plane S, the inclined portion of the present invention may include a protrusion, which does not lie in the inclined plane S, between the start point and end point of the inclined plane S. However, from a viewpoint of preventing the solder from adhering to the inclined portion, the present invention requires that the distance from the solder to the inclined portion be greater than the distance from the solder to the arc-shaped portion R in the aforementioned comparative example. 
         [0142]    Furthermore, with regard to the inclined portion of the present invention, its projection toward the solder is more desirable than its projection in such a way as to become farther from the solder. The reason for this is that in the case where the inclined portion projects in such a way as to become farther from the solder, there is likelihood that the space which receives the header-side terminal  10  cannot be left. Note that, as long as the space which receives the header-side terminal  10  can be left, even the inclined portion projecting in such a way as to become farther from the solder  80  is also included in the inclined portion of the present invention. This is because even the inclined portion projecting in such a way as to become farther from the solder  80  also can achieve the object of the present invention, that is to say, the prevention of the solder from adhering to the inclined portion, as long as the inclined portion as a whole extends along the inclined plane. 
         [0143]    Descriptions will be hereinbelow provided for examples of the shape of the inclined portion of the present invention which is not the inclined portion formed from the flat portion. 
         [0144]    The inclined portion of the present invention may include one or more bending portions projecting toward the solder. In this case, the inclined portion of the present invention is formed by combining plurality of flat portions which continue via one or more bending portions. For example, as shown in  FIG. 13 , the combination of the plurality of bending portions as the inclined portion of the present invention may be a combination of flat portions  40   f   1 ,  40   f   2  provided with a bending portion interposed in between in such a way that the bending portion projects toward the solder  80 . Any combination may be employed as the combination of the plurality of flat portions forming the inclined portion of the present invention, as long as the plurality of flat portions in combination are placed farther from the solder  80  than the arc-shaped portion R of the comparative example is. The reason for this is that as long as the plurality of flat portions in combination are placed farther from the solder  80  than the arc-shaped portion R of the comparative example is, it is possible to obtain an effect of inhibiting the solder  80  from adhering to the plurality of flat portions in combination. 
         [0145]    The inclined portion of the present invention may be a curving portion projecting toward the solder  80 . In this case, the curving portion forming the inclined portion of the present invention may take on any shape, as long as the curving portion as a whole extends along the inclined plane S joining the lower end of the falling portion  40   e  and the end portion of the flat portion  40   g . Incidentally, the “curving portion as a whole extends along the inclined plane S” means that although no part of the curving portion between the start point and the end point of the curving portion lies in the inclined plane S, the start point and the end point of the curving portions lie in the inclined plane S. The inclined portion of the present invention may be a curving portion  40   f   3  shown in  FIG. 13 , for example. Note that, in order for the curving portion  40   f   3  to reduce more of the likelihood that the solder  80  is prevented from adhering to the curving portion  40   f   3  than the arc-shaped portion does, the curving portion  40   f   3  needs to have a curvature radius which is larger than that of the arc-shaped portion R. In other words, the distance from the solder  80  to the curving portion  40   f   3  needs to be larger than the distance d 1  from the solder  80  to the arc-shaped portion R. 
         [0146]    Furthermore, the inclined portion of the present invention may take on any other shape than the foregoing shapes, as long as the inclined portion is provided at a position which is farther from the solder  80  than the position of the arc-shaped portion R is. For example, the inclined portion of the present invention may be formed from a combination of differently-shaped portions. For example, as shown in  FIG. 13 , the combination of differently-shaped portions may be a combination of three portions, that is to say, two flat portions  40   f   4 ,  40   f   5  and a curving portion  40   f   6  provided between the two flat portions  40   f   4 ,  40   f   5 . The combination of differently-shaped portions is not limited to the ones shown in  FIG. 13 . Any combination of differently-shaped portions may be employed as the inclined portion of the present invention, as long as the combination includes at least one flat portion and at least one curving portion. In this case, too, the inclined portion of the present invention may take on any shape, as long as the inclined portion as a whole extends along the inclined plane S joining the lower end of the falling portion  40   e  and the end portion of the flat portion  40   g . With regard to the combination of differently-shaped portions, no part of the combination between the start point and the end point of the combination does have to lie in the inclined plane S, as long as: the combination projects toward the solder; and the start point and the end point of the combination lie in the inclined plane S. 
         [0147]    In addition, it is desirable that the distance d 4  between the rising portion  40   b  and the falling portion  40   e  shown in  FIG. 7  be equal to or less than the thickness of the base material of the socket-side terminal  40  (before the process). To put it concretely, it is desirable that the distance d 4  be equal to or less than the thickness t 1  of the one end and the thickness t 2  of the opposite end of the inverted U-shaped portion  40   c . The use of this configuration makes it possible to reduce the width dimension W 2  (see  FIGS. 3 and 6 ) or the dimension d 5  (see  FIG. 7 ) of the socket to a large extent. 
         [0148]    Next, referring to  FIGS. 3, 4, 14, 15, 20 to 27, 28, 40 to 53, and 54 , descriptions will be provided for the header-side retaining fittings  20  and the socket-side retaining fittings  50  of the embodiment. 
         [0149]    To begin with, descriptions will be provided for the header-side retaining fittings  20 . 
         [0150]    As described above, each header-side retaining fitting  20  has the same shape as each header-side terminal  10 . However, how to attach the header-side retaining fitting  20  to the header housing  30  is different from how to attach the header-side terminal  10  to the header housing  30 . 
         [0151]    As shown in  FIGS. 14, 15, 20 to 27, and 28 , each header-side retaining fitting  20  includes a protrusion  20   a  to be fixed to a conductor wiring pattern  375  on the circuit board  170  using solder  380 . The protrusion  20   a  projects from the front surface or rear surface (in  FIG. 14 , a side surface) of the header housing  30  in a way that the upper surface of the protrusion  20   a  is placed flush with the upper surface of the header housing  30 , or the outer surface of the bottom surface portion  30   a.    
         [0152]    As shown in  FIGS. 14, 15, 20 to 27, and 28 , the header-side retaining fitting  20  includes an inner side portion  20   b  continuing to the protrusion  20   a . The inner side portion  20   b  penetrates, while curving, the joining portion where the bottom surface portion  30   a  and the edge portion  30   e  of the header housing  30  are joined together. Subsequently, the inner side portion  20   b  extends along the inner surface of the edge portion  30   e  to the tip end portion of the edge portion  30   e . A V-shaped groove  20   c , or a V-shaped notch, is provided to the inner side surface of the inner side portion  20   b . Part of the resin forming the header housing  30  enters the V-shaped groove  20   c  of the header-side retaining fitting  20 . 
         [0153]    The header-side retaining fitting  20  includes a locked portion  20   e  continuing to a tip end portion  20   d . As shown in  FIGS. 14, 15, 20 to 27, and 28 , once the header-side retaining fitting  20  is fitted into the socket-side retaining fitting  50 , the locked portion  20   e  is inserted deeper than a locking piece portion  50   e . For this reason, when the header-side retaining fitting  20  is pulled out of the socket-side retaining fitting  50 , the locked portion  20   e  comes into contact with the locking piece portion  50   e . In other words, the locked portion  20   e  of the header-side retaining fitting  20  is locked by the locking piece portion  50   e  of the socket-side retaining fitting  50 . Thereby, the header-side retaining fitting  20  is inhibited from being pulled out of the socket-side retaining fitting  50 . To put it concretely, the header-side retaining fitting  20  cannot be pulled out of the socket-side retaining fitting  50  by mere application of external force less than a predetermined value. On the other hand, the header-side retaining fitting  20  can be pulled out of the socket-side retaining fitting  50  by application of external force equal to or greater than the predetermined value. In sum, the locked portion  20   e  of the header-side retaining fitting  20  and the locking piece portion  50   e  of the socket-side retaining fitting  50  form a lock mechanism in which the locked portion  20   e  and the locking piece portion  50   e  can be unlocked from each other by the application of external force equal to or greater than the predetermined value. 
         [0154]    The header-side retaining fitting  20  includes an outer side portion  20   f  continuing to the tip end portion  20   d  via the locked portion  20   e , and extending along the outer surface of the edge portion  30   e.    
         [0155]    Next, descriptions will be provided for the socket-side retaining fittings  50 . 
         [0156]    As shown in  FIGS. 3 and 4 , each socket-side retaining fitting  50  includes a central portion  50   b  extending in the width direction, and covering the side surface of the socket housing  60 . As shown in  FIGS. 3 and 4 , the socket-side retaining fitting  50  includes arm portions  50   c  extending from the central portion  50   b  to predetermined positions in such a way as to cover the parts of the front surface and rear surface of the socket housing  60 . As shown in  FIGS. 3, 4, 46 to 53, and 54 , the socket-side retaining fitting  50  includes leg portions  50   a  extending from the central portion  50   b  to predetermined positions in such a way as to cover parts of the bottom surface of the socket housing  60 . The leg portions  50   a  include portions extending from the central portion  50   b  along the bottom surface of the socket housing  60 , and respectively projecting from the front surface and rear surface of the socket housing  60 . 
         [0157]    As shown in  FIGS. 3, 4, 46 to 53, and 54 , the socket-side retaining fitting  50  includes rising portions  50   d  extending from tip end portions of the arm portions  50   c  at predetermined positions in a thickness direction of the socket housing  60 . The socket-side retaining fitting  50  includes the locking piece portions  50   e  curving from tip end portions of the rising portions  50   d  toward the rectangular plate-shaped inside. 
         [0158]    In cross-sectional views shown in  FIGS. 14 and 15 , each rising portion  50   d  and the corresponding locking piece portion  50   e  are jointly shaped like the upended letter L. The rising portion  50   d  and the corresponding locking piece portion  50   e  enter the edge portion  60   c  from the under (see  FIGS. 3 and 4 ), curve inside the edge portion  60   c , and penetrate the edge portion  60   c , thereafter projecting into the frame-shaped space  60   a.    
         [0159]    In the embodiment, both the projecting portion of each leg portions  50   a  and the lower end portion of the corresponding rising portion  50   d  shown in  FIG. 14  are designed to be fixed to the circuit board  70  using solder. Since the socket  2  includes two soldered portions like this, the socket  2  is firmly fixed to the circuit board  70 . Furthermore, the fixing of the lower end portion of the rising portion  50   d  to the circuit board  70  using the solder inhibits flexure of the socket-side retaining fitting  50  as a whole which is caused by rotational force around an axis extending in the width direction defined by the width dimension W 2  of the socket-side retaining fitting  50  in  FIG. 3 . 
         [0160]    There is a case where as indicated with an arrow Fout in  FIG. 15 , external force is applied in such a way as to pull the header-side retaining fitting  20  out of the corresponding socket-side retaining fitting  50 . In this case, the locking piece portion  50   e  of the socket-side retaining fitting  50  locks the locked portion  20   e  of the header-side retaining fitting  20 , and restricts the movement of the locked portion  20   e . This inhibits the header-side retaining fitting  20  from coming off the socket-side retaining fitting  50 . For this reason, in a case where the header-side retaining fitting  20  should not be pulled out of the socket-side retaining fitting  50 , the header-side retaining fitting  20  is inhibited from being unexpectedly pulled out of the socket-side retaining fitting  50  by the occurrence of force less than force needed to pull the header-side retaining fitting  20  out of the socket-side retaining fitting  50  in a direction of the pulling. For example, in a case where pulling-out force less than the force needed to pull the header-side retaining fitting  20  out of the socket-side retaining fitting  50  occurs to the connector  120  due to falling or the like of the electronic device including the connector  120 , the header  1  can be inhibited from being unexpectedly separated from the socket  2 . For this reason, the locking piece portion  50   e  of the socket-side retaining fitting  50  and the locked portion  20   e  of the header-side retaining fitting  20  form a lock mechanism in which the locking piece portion  50   e  and the locked portion  20   e  can be unlocked from each other by the application of external force equal to or greater than the predetermined value. In short, the locking piece portion  50   e  functions to keep the header  1  and the socket  2  electrically connected to each other. 
         [0161]    As shown in  FIGS. 14 and 15 , the edge portions  60   c  of the socket housing  60  include the covering portions  60   e  covering at least parts of the locking piece portions  50   e  of the socket-side retaining fittings  50 . As shown in  FIG. 15 , each covering portion  60   e  causes reaction force Fin against the pulling-out force in the corresponding locking piece portion  50   e  when pulling-out force Fout occurs in a direction in the corresponding locked portion  20   e  comes off the locking piece portion  50   e . Thereby, the covering portion  60   e  restricts the movement of the locking piece portion  50   e  of the socket-side retaining fittings  50  in a direction indicated with a corresponding turning arrow in  FIGS. 14 and 15 . In other words, the covering portion  60   e  inhibits outward movement of the locking piece portion  50   e  and the corresponding rising portion  50   d . That is to say, flexure of the portion shaped like the upended letter L, as a cantilevered beam whose fixed end is the solder  280 , is inhibited. Thereby, the occurrence of unexpected unlocking, that is to say, the locked portion  20   e  coming off the locking piece portion  50   e , due to the flexure of the portion shaped like the upended letter L is securely prevented. To put it concretely, it is possible to securely prevent the occurrence of the unexpected separation of the connector  120 , such as the header  1  coming off the socket  2  due to the falling of the electronic device in which the connector  120  is installed. 
         [0162]    In addition, as described above, each socket-side retaining fitting  50  is fixed at the two parts to the conductor wiring pattern  275  of the circuit board  70  using the solders  280 . To put it concretely, the leg portions  50   a  of each socket-side retaining fitting  50  shown in  FIGS. 3, 4, 40 to 53, and 54  are fixed to the conductor wiring pattern  275  of the circuit board  70  using the solders  280 . Furthermore, the tip ends of the arm portions  50   c , which are concurrently the lower ends of the rising portions  50   d , in the socket-side retaining fitting  50  shown in  FIGS. 14, 15, 40 to 53, and 54  are fixed to the conductor wiring pattern  275  of the circuit board  70  using the solders  280 . 
         [0163]    The covering portions  60   e  of the socket housing  60  are provided at positions which make the covering portions  60   e  prevent the solders  280 , as melted, from rising up to the locking piece portions  50   e  of the socket-side retaining fittings  50 . For this reason, each covering portions  60   e  brings about two effects, that is to say, an effect of preventing the locked portion  20   e  from coming off the locking piece portion  50   e , and an effect of preventing the solder  280 , as melted, from rising along the surface of the rising portion  50   d.    
         [0164]    As described above, part of each socket-side terminal  40  and part of each socket-side retaining fittings  50  are attached to the socket housing  60  by the insert molding. The covering portions  60   e  are formed integrally with the rest of the socket housing by the insert molding in the same step. For this reason, the covering portions  60   e  can be formed without increasing the number of production steps. 
         [0165]    Referring to  FIGS. 16 to 19 , descriptions will be provided for a header  1 A of a different example of the embodiment. 
         [0166]    The header  1 A of the different example includes a header housing  35  instead of the header housing  30 . The header housing  35  includes: a bottom surface portion  35   a ; two edge portions  35   b  rising from the bottom surface portion  35   a ; and two edge portions  35   c  rising from the bottom surface portion  35   a . The two edge portions  35   b  each extend in the lengthwise direction of the header  1 , and both face each other. The two edge portions  35   c  each extend in the width direction of the header  1 , and both face each other. The bottom surface portion  35   a , the two edge portions  35   b  and the two edge portions  35   c  form a recessed portion in the center of the header housing  35 . 
         [0167]    The header  1 A of the different example is different from the header  1  in that: the number of posts, or the number of heard-side terminals  10  is larger in the header  1 A than in the header  1 ; and accordingly, the header housing  35  is longer than the header housing  30 . Furthermore, the header housing  35  is different from the header housing  30  in that the header housing  35  includes a structure which receives the header-side terminals corresponding to the increased number. 
         [0168]    The header housing  35  of the different example has the same configuration as the header housing  30 , except for the above-described differences between the header housing  35  and the header housing  30 . The configuration which is the same between the header housing  30  and the header housing  35  of the different example has already been described, and therefore will not be described repeatedly here. 
         [0169]      FIGS. 20 to 28  show the header-side terminal  10  (the header-side retaining fitting  20 ) to be attached to the header  1  and the header  1 A. As described above, the header-side terminal  10  and the header-side retaining fitting  20  have the same structure. The structure of the header-side terminal  10  and the header-side retaining fitting  20  is the same between the header  1  and the header  1 A of the different example, and has already been described. For this reason, the structure of the header-side terminal  10  and the header-side retaining fitting  20  will not be described repeatedly here. 
         [0170]    The header  1 A of the different example has the same configuration as the header  1 , except for the above-described differences. 
         [0171]    Referring to  FIGS. 29 to 36 , descriptions will be provided for a socket  2 A of the different example of the embodiment. 
         [0172]    The socket  2 A of the different example includes a socket housing  65  instead of the socket housing  60 . The socket housing  65  includes a frame-shaped space  65   a  extending along the four sides of the rectangle of the socket housing  65 . The frame-shaped space  65   a  is surrounded by: two mutually-facing edge portions  65   c  each extending in the long-side direction of the rectangle; and two mutually-facing edge portions  65   d  each extending in the short-side direction of the rectangle. The frame-shaped space  65   a  surrounds an island portion  65   b  positioned at the center of the frame-shaped space  65   a , and shaped almost like a rectangular parallelepiped. In the socket  2 A, covering portions  65   e  of the socket housing  65  restrict the movement of the locking piece portions  50   e  of the socket-side retaining fittings  50 . 
         [0173]    The socket  2 A of the different example is different from the socket  2  in that: the number of socket-side terminals  40  is larger in the socket  2 A than in the socket  2 ; and accordingly, the socket housing  65  is longer than the socket housing  60 . The socket housing  65  is further different from the socket housing  60  in that the socket housing  65  includes cut portions which receive the socket-side terminals corresponding to the increased number. The socket  2 A of the different example has the same configuration as the socket  2 , except for the above-described differences. 
         [0174]    Next, referring to  FIGS. 35 and 36 , descriptions will be provided for a pitch between terminals, and a distance between mutually-facing terminals, in the header and the socket. 
         [0175]    As learned from  FIG. 35 , in the header  1 A of the different example, the pitch between each two of the header-side terminals  10  is P, and is constant. Furthermore, the pitch between the header-side terminal  10  and the header-side retaining fitting  20  is 2P. In other words, the pitch between the header-side terminal  10  and the header-side retaining fitting  20  is an integer multiple of the pitch between each two of the header-side terminals  10 . In addition, the header-side terminals  10  and the header-side retaining fittings  20  have the same shape. For these reasons, an interval H 1  between the outer edges of the locked portions  10   e  of the mutually-facing header-side terminals  10  shown in  FIG. 5  and an interval H 2  between the outer edges of the locked portions  20   e  of the mutually-facing header-side retaining fittings  20  shown in  FIG. 14  are equal to each other (H 1 =H 2 ), as shown in  FIG. 35 . These make it very easy to design and manufacture the header-side terminals  10  and the header-side retaining fittings  20 . Accordingly, it is possible to use a manufacturing method of cutting both the header-side terminals  10  and the header-side retaining fittings  20  from the same material. 
         [0176]    As learned from  FIG. 36 , the pitch between each two of the socket-side terminals  40  is P, and is constant. Furthermore, the pitch between the socket-side terminal  40  and the socket-side retaining fitting  50  is 2P. In other words, the pitch between the socket-side terminal  40  and the socket-side retaining fitting  50  is an integer multiple of the pitch between each two of the socket-side terminals  40 . In addition, a distance S 1  between the inner edges of the locking portions  40   d  of the mutually-facing socket-side terminals shown in  FIG. 5  and a distance S 2  between the inner edges of the locking piece portions  50   e  of the mutually-facing socket-side retaining fittings  50  shown in  FIG. 14  are equal to each other (S 1 =S 2 ), as shown in  FIG. 36 . The structures of the socket-side terminals  40  and the socket-side retaining fittings  50  like these are those suitable to receive the header-side terminals  10  and the header-side retaining fittings  20 . 
         [0177]      FIGS. 37 to 45  show the socket-side terminal  40  to be attached to the socket  2  of the embodiment and the socket  2 A of the different example. As described above, the socket-side terminals  40  are the same between the socket  2  and the socket  2 A of the different example, and have already been described. For this reason, the socket-side terminals  40  will not be described repeatedly here. 
         [0178]      FIGS. 46 to 54  show the socket-side retaining fitting  50  to be attached to the socket  2  of the embodiment and the socket  2 A of the different example. As described above, the socket-side retaining fittings  50  are the same between the socket  2  and the socket  2 A of the different example, and have already been described. For this reason, the socket-side retaining fittings  50  will not be described repeatedly here. 
         [0179]    The socket  2 A of the different example can bring about the same effect as the socket  2  does. 
         [0180]      FIGS. 55 to 63  show a socket-side terminal  400  of a different example which can be attached to the socket  2  of the embodiment and the socket  2 A of the different example. A falling portion  40   e   1  of the socket-side terminal  400  of the different example is different from the falling portion  40   e  of the socket-side terminal  40  in that the falling portion  40   e   1  includes a curving surface portion  40   e   2  facing a rising portion  40   b . Furthermore, the falling portion  40   e   1  of the socket-side terminal  400  of the different example is different from the falling portion  40   e  of the socket-side terminal  40  in that the curving surface portion  40   e   2  is thicker in its lower portion than in its upper portion. 
         [0181]    The reasons for the above-mentioned differences come from the difference between a method of manufacturing parts in the socket-side terminal  40  and a method of manufacturing parts in the socket-side terminal  400  of the different example, as follows. The locking portion  40   d  of the socket-side terminal  40  is formed from the base material by rolling forming. On the other hand, the locking portion  40   d   1  of the socket-side terminal  400  of the different example shown in  FIGS. 55 to 63  is formed from the base material by simple bending forming. In short, the above-mentioned differences are caused by the difference between the rolling forming and the bending forming. 
         [0182]    The parts of the socket-side terminal  400 , except for the falling portion  40   e   1  and the locking portion  40   d   1  but inclusive of the inclined portion  40   f , have the same structures as the corresponding parts of the socket-side terminal  40 . The same structures have already been described. For this reason, the parts which have the same structures between the socket-side terminal  400  and the socket-side terminal  40  will not be described repeatedly here. 
         [0183]    The socket-side terminal  400  of the different example can bring about almost the same effect as the socket-side terminal  40  does. 
         [0184]    It should be noted that the foregoing embodiment is an example of the present invention. For this reason, it is a matter of course that: the present invention is not limited to the above-described embodiment; and various changes can be made to the present invention depending on designs and the like within a scope not departing from the technical idea related to the present invention, even in embodiments other than the present one. 
       INDUSTRIAL APPLICABILITY 
       [0185]    The present invention can provide a socket, a connector using the socket, and a header used in the connector, which are capable of inhibiting the header-side retaining fittings from being unlocked from the socket-side retaining fittings under a situation where the unlocking is not allowed.