Patent Publication Number: US-8535076-B2

Title: Electrical connector

Description:
BACKGROUND TECHNOLOGY AND RELATED TECHNOLOGY 
     The present invention relates to an electrical connector. More specifically, the present invention relates to an electrical connector such as a circuit board electrical connector to be mounted on a circuit board. 
     Patent Reference has disclosed a conventional circuit board electrical connector described. The conventional circuit board electrical connector is disposed on a circuit board for receiving a flexible flat cable (FFC) from above, so that the circuit board is connected to the FFC. The conventional electrical connector disclosed in Patent Reference includes a housing, a guide member attached to the housing to be slidable, an actuator rotatably attached to the housing, a plurality of terminals arranged and held in the housing, and a plurality of ground members arranged in the housing.
     Patent Reference: Japanese Patent Publication No. 2006-190596   

     In the conventional circuit board electrical connector, the housing has a receiving hole for inserting the FFC from above, and the receiving hole passes through the housing in a vertical direction thereof. The terminals held are disposed in the housing and held on one of two sidewalls of the housing. The sidewalls are parallel to each other in a lateral direction of the housing, i.e., in a terminal arrangement direction. 
     More specifically, in the conventional circuit board electrical connector, terminal receiving grooves are provided in one of the sidewalls so as to extend through in the vertical direction. Holding sections of the terminals are pressed in the terminal receiving grooves from a bottom portion of the housing, so that the terminals are held in the housing. Each of the terminals has an elastic arm portion, which extends upward in the receiving hole from the bottom portion of the housing, and a contact section is formed at a tip of the elastic arm portion for elastically contacting with the FFC inserted from above. 
     In the conventional circuit board electrical connector, each of the ground members includes a straight section extending along an outer surface of the other of the sidewalls, a curved section folded back across an upper end part of the other of the sidewalls from an upper end of the straight section, and a ground contact section extending downward from the curved section along an inner surface of the other of the sidewalls. 
     In the conventional circuit board electrical connector, a ground attachment section is formed in the housing so as to protrude from an outer surface of the other of the sidewalls. The straight section of each of the ground members includes a securing section at a position close to the bottom portion of the housing, so that the ground attachment section holds the securing section. In addition, the upper end portion of the other of the sidewalls between the ground members extends upward, so that a ground receiving recesses is formed in a groove shape at a position of each of the ground members. Accordingly, the curved sections of the ground members are held in the ground receiving recesses. 
     In the conventional circuit board electrical connector, when the FFC is inserted in the receiving hole of the housing from above, the ground contact sections of the ground members are pressed against the FFC, so that an upper side portion of the straight section from the securing section to the ground contact section becomes elastically deformed to be slightly away from the other of the sidewalls of the housing. 
     As described above, in the conventional circuit board electrical connector disclosed in Patent Reference, each of the ground members includes the curved section that is folded back across the upper end of the other of the sidewalls of the housing. Accordingly, a height of the ground member is larger than that in a case when the ground member is made to have a dimension substantially the same as the housing. 
     In addition, as described above, the upper end portion of the other of the sidewalls between the ground members extends upward, so that the ground receiving recesses is formed in the groove shape for holding the curved section of each of the ground members. Accordingly, the height of the housing becomes larger by a dimension above the upper end section to form the extending section. Furthermore, the ground attachment section to hold the straight section of the ground member is formed protruding from the outer surface of the other wall. Accordingly, the dimension of the housing becomes larger in a thickness direction of the sidewall. As a result, an entire size of the conventional circuit board electrical connector increases in the height direction and the thickness direction. 
     In view of the above, an object of the present invention is to provide a circuit board electrical connector capable of increasing a spring length of a terminal without increasing an entire size of the circuit board electrical connector. 
     Further objects and advantages of the present invention will be apparent from the following description of the present invention. 
     SUMMARY OF THE INVENTION 
     In order to attain the objects described above, according to the present invention, an electrical connector to be disposed on a circuit board includes a housing, which has two sidewalls perpendicular to a surface of the circuit board and receives a flat conductive member in a receiving space formed between the two sidewalls from above. The electrical connector further includes a plurality of first terminals to be held by one of the sidewalls in an arrangement direction thereof parallel to the surface of the circuit board, and a plurality of second terminals to be held by the other of the sidewalls in an arrangement direction thereof. 
     According to the present invention, in the circuit board electrical connector, the first terminals and the second terminals are attached to the one and the other of the sidewalls, respectively, and are situated near a bottom portion of the housing. Each of the first terminals has a flexible first elastic arm portion. The first elastic arm portion extends upward from the bottom portion at a position closer to the other of the sidewalls than the flat conductive member between the sidewalls. The first elastic arm portion has a first contact section that protrudes toward the flat conductive member, and can elastically contact with the flat conductive member at the first contact section. 
     According to the present invention, in the circuit board electrical connector, each of the second terminals has a flexible second elastic arm portion. The second elastic arm portion extends upward further than an upper end of the first elastic arm portion. The second elastic arm portion has a second contact section that protrudes towards the flat conductive member at a position above than the upper end of the first elastic arm portion, and can elastically contact with the flat conductive member at the second contact section. 
     According to the present invention, the second terminal is attached to the other of the sidewalls near the bottom portion of the housing, and the second elastic arm portion of the second terminal extends upward between the sidewalls. Therefore, different from the conventional circuit board electrical connector, the housing does not have the curved section that is provided across an upper end section of the other of the sidewalls, so that a height of the terminal is smaller by a corresponding length. In the housing, it is not necessary to form a recess to hold the curved section of the ground member, so that the height of the housing does not become large. Moreover, it is not necessary to form the section protruding from an outer surface of the other of the sidewalls to secure the second terminal, so that a dimension of the housing in a thickness direction thereof does not increase. 
     According to the present invention, in the circuit board electrical connector, the second elastic arm portion is formed to extend to near the upper end part of the sidewall within a height range of the other of the sidewalls of the housing. Accordingly, it is possible to secure an enough spring length within a height dimension of a height range of the housing. 
     According to the present invention, in the circuit board electrical connector, the second elastic arm portion extends in an inclined state so as to be away from the other of the sidewalls as the second elastic arm portion extends upward. Further, the second elastic arm portion is situated to approaching the other of the sidewalls as the second elastic arm portion extends upward from the bent portion at a middle point of the second elastic arm portion. It is preferred that the second contact section is formed at the bent section of the second elastic arm portion. 
     According to the present invention, in the circuit board electrical connector, when the flat conductive member with a regular thickness is inserted between the sidewalls and contacts with the second contact sections of the second terminals, the second contact sections receive a pressing force from the flat conductive member. Therefore, the second elastic arm portions elastically displace as a whole toward the other of the sidewalls. It is noted that the second elastic arm portion of the second terminal is held like a cantilever in a free state. Accordingly, the second elastic arm portions can easily displace. 
     In addition, when the flat conductive member has a large thickness, the second contact sections elastically deform to a large extent. When the second contact sections elastically deform for a displacement amount greater than a specific displacement amount, the upper end section of the second elastic arm portion contacts with the other of the sidewalls, so that the second elastic arm portion becomes a bar fixed at the both ends, thereby preventing a further elastic deformation. As a result, it is possible to prevent an excess elastic deformation and the second elastic arm portion from being damaged (permanent deformation in fatigue). Further, it is possible to achieve a large contact pressure. 
     According to the present invention, in the circuit board electrical connector, the first terminals and the second terminals are preferably held at the same positions in the arrangement direction. 
     In general, the flat conductive member may include a first circuit section that corresponds to the first terminals and a second circuit section that corresponds to the second terminals. The first circuit section and the second circuit section are formed in two layers in a thickness direction of the flat conductive member. The first circuit section and the second circuit section include connection pad portions disposed at the same vertical positions on a surface of the flat conductive member in the width direction thereof. 
     According to the present invention, the first terminals and the second terminals may be situated at the same positions in the arrangement direction. Accordingly, when the first circuit section and the second circuit section include the connection pads disposed at the same positions in the width direction, it is possible to electrically connect the first terminals and the second terminals to the first circuit section and the second circuit section arranged with a small pitch in the width direction. 
     According to the present invention, the circuit board electrical connector may further include a pressing member that can pivotally move between an open position where the flat conductive member can be inserted into the receiving space of the housing and a close position where the flat conductive member is pressed against the first contact sections of the first terminals and the second contact sections of the second terminals. 
     According to the present invention, in the circuit board electrical connector, the pressing member may have a rotary shaft section as a rotary center thereof disposed at the same position as at least a part of the first terminal. Further, the part of the first terminals has a support arm portion that extends upward at a position closer to the one of the sidewalls than the flat conductive member. The support arm portion may have a rotary support section that rotatably supports the rotary shaft section. In addition, the second terminal may function as a ground terminal. 
     As described above, according to the present invention, in the circuit board electrical connector, the first terminals and the second terminals are attached near the bottom portion of the housing. Further, the first elastic arm portion of each of the first terminals and the second elastic arm portion of each of the second terminals extend upward between the sidewalls of the housing. 
     On the other hand, in the conventional circuit board electrical connector, the terminal is disposed such that the straight section thereof is situated along the outer surface of the sidewall. Further, the curved section is formed by folding the terminal over the upper end part of the sidewall. In contrast, the circuit board electrical connector of the present invention does not have the curved section. Accordingly, as opposed to the conventional circuit board electrical connector, it is possible to reduce a dimension of the circuit board electrical connector in a height direction of the housing. 
     In addition, in the circuit board electrical connector of the present invention, it is not necessary to form the holding section to hold the terminal at the outer surface of the sidewall as in the conventional circuit board electrical connector. Accordingly, it is possible to reduce the dimension of the circuit board electrical connector in the thickness direction of the sidewall. As a result, it is possible to reduce the size of the circuit board electrical connector both in the height direction and the thickness direction. 
     Furthermore, in the circuit board electrical connector of the present invention, it is possible to extend the second elastic arm portion of the second terminal from the bottom portion of the housing to near the upper end section of the sidewall within the range of the height of the other of the sidewalls. Accordingly, it is possible to increase a length of the second elastic arm portion. As a result, it is possible to obtain the sufficiently long spring length, so that the second elastic arm portion can easily elastically displace, thereby making it easy to insert the flat conductive member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a circuit board electrical connector and a flat conductive member before the flat conductive member is inserted into the circuit board electrical connector in a state that a pressing member is situated at an open position according to an embodiment of the present invention; 
         FIG. 2  is a perspective view showing the circuit board electrical connector and the flat conductive member before the flat conductive member is inserted into the circuit board electrical connector in a state the pressing member is situated at a close position according to the embodiment of the present invention; 
         FIGS. 3(A) and 3(B)  are longitudinal sectional views showing the circuit board electrical connector before the flat conductive member is inserted into the circuit board electrical connector according to the embodiment of the present invention, wherein  FIG. 3(A)  is a sectional view of the circuit board electrical connector taken along a line IIIA-IIIA in  FIG. 1  and  FIG. 3(B)  is a sectional view of the circuit board electrical connector taken along a line IIIB-IIIB in  FIG. 1 ; 
         FIG. 4  is a sectional view of the circuit board electrical connector corresponding to  FIG. 3(B)  in a state that first terminals and second terminals is omitted according to the embodiment of the present invention; 
         FIGS. 5(A) and 5(B)  are views showing the circuit board electrical connector according to the embodiment of the present invention, wherein  FIG. 5(A)  is a bottom view of the circuit board electrical connector and  5 (B) is a sectional view of the circuit board electrical taken along a line VB-VB in  FIG. 3(B) ; and 
         FIGS. 6(A) and 6(B)  are longitudinal sectional views showing the circuit board electrical connector after the flat conductive member is inserted into the circuit board electrical connector according to the embodiment of the present invention, wherein  FIG. 6(A)  is a sectional view of the circuit board electrical connector corresponding to  FIG. 3(A)  and  FIG. 6(B)  is a sectional view of the circuit board electrical connector corresponding to  FIG. 3(B) . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a perspective view of a circuit board electrical connector  1  and a flat conductive member before insertion of the flat conductive member P according to an embodiment of the present invention, in which a pressing member  40  is in an open state.  FIG. 2  is a perspective view of the circuit board electrical connector  1  shown in  FIG. 1  and the flat conductive member P before an insertion of the flat conductive member P, in which the pressing member  40  is in a close position. 
     In the embodiment of the present invention, the circuit board electrical connector  1  (hereinafter simply referred to as the connector  1 ) is an electrical connector to be disposed on a circuit board (not illustrated), and receives the flat conductive member P from above and then connects to the flat conductive member P. 
     As shown in  FIG. 1 , one surface of a main body P 1  of the flat conductive member P has a reinforcing plate P 2  attached onto a lower end portion. On the other surface of the main body P 1 , connection pads (not illustrated) of a signal circuit section to be connected to first terminals  20 , which will be described later, are exposed at the lower end portion, and the connection pads are formed being arranged in the width direction of the flat conductive member P. A ground bar P 3  as a ground circuit section to be connected to second terminals  30 , which will be described later, is attached across the whole width direction at a position near the lower end part of the main body P 1  but above the signal circuit section. 
     In other words, in the flat conductive member P, the signal circuit section that corresponds to the first terminals  20  and the ground bar P 3  that corresponds to the second terminals  30  are formed in two layers along the thickness direction of the flat conductive member P. In addition, the connection pad portion of the signal circuit section is disposed below the ground bar P 3  while extending over the same width position of the flat conductive member P on the other surface of the flat conductive member P. 
     In the embodiment of the present invention, the connector  1  includes a housing  10 , which has an outer shape of a generally rectangular solid and receives the flat conductive member P from above, first terminals  20 , which are arranged and held as signal terminals at the equal intervals in the longitudinal direction of the housing  10  (the terminal arrangement direction that is horizontal to a circuit board surface), second terminals  30  as ground terminals, a pressing member  40  that can freely pivotally move between the open position shown in  FIG. 1  and the close position shown in  FIG. 2 , and a locking hardware  50  to hold the pressing member  40  attached onto the housing  10  at the open position. 
     The housing  10  includes a sidewall  11  and a sidewall  12 , which extend vertically from a surface of the circuit board and are parallel to each other in the longitudinal direction, and two end walls  13  that respectively join the ends of the sidewall  11  and the sidewall  12 . The space, which is formed by the sidewalls  11  and  12  and the end walls  13  and is opened upward, is formed as a receiving groove  14 , which is receiving space to receive the flat conductive member P from above. 
     As will be described later, the first terminals  20  are arranged along and held by the sidewall  11 , and the second terminals  30  are arranged along and held by the sidewall  12 . As shown in  FIG. 1 , there are provided less number of the second terminals  30  than the first terminal  20 , and the second terminals  30  are provided in positions corresponding to a part of the plurality of the first terminals  20  in the terminal arrangement direction. Accordingly, in the embodiment, since the second terminals  30  are held at the same positions as the first terminals  20  in the terminal arrangement direction, it is possible to electrically connect to the circuit sections that are arranged at tight pitches in the width direction in the flat conductive member P. 
     As well shown in  FIGS. 1 and 2 , the sidewall  12  has pairs of protruding strips  12 A, which vertical extend, at positions where the second terminals  30  are respectively held along the lateral direction, i.e. terminal arrangement direction, so as to protrude from an inner wall surface of the sidewall  12  toward inside of the receiving groove  14 . As will be described later, the groove between each pair of the protruding strips  12 A composes a part of the receiving groove  15  to hold a part of the first terminals  20  and the second terminals  30 . 
     As can be seen in  FIGS. 1 and 2 , each end wall  13  has a recess  16  to house and hold the locking hardware  50 , being opened upward, and has a locking hardware attachment hole (not illustrated), which is formed therethrough in the vertical direction, on a bottom portion of the recess  16 . The recess  16  is made wider in the terminal arrangement direction near the sidewall  11  where the sidewalls  11  face each other, and allows elastic displacement of the locking hardware  50  at the wider portion. 
       FIGS. 3(A) and 3(B)  are longitudinal sectional views showing the circuit board electrical connector  1  before the flat conductive member P is inserted into the circuit board electrical connector  1  according to the embodiment of the present invention.  FIG. 3(A)  is a sectional view of the circuit board electrical connector  1  taken along a line IIIA-IIIA in  FIG. 1 .  FIG. 3(B)  is a sectional view of the circuit board electrical connector  1  taken along a line IIIB-IIIB in  FIG. 1 . 
     More specifically,  FIG. 3(A)  shows a section which includes both first terminal  20  and second terminal  30  that are respectively arranged in the terminal arrangement directions.  FIG. 3(B)  shows a section, which includes only the first terminal  20  that is arranged in the terminal arrangement direction. 
     As shown in  FIGS. 3(A) and 3(B) , as for the sidewall  11  and the sidewall  12  that face each other, one sidewall  11  has a smaller height than the other sidewall  12 . The sidewall  11  includes attachment holes  11 A, which are provided therethrough in the vertical direction to attach the first terminals  20 . In addition, as shown in  FIG. 3(A) , the sidewall  12  has attachment holes  12 B, which are opened downward to attach the second terminals  30 . 
     In the embodiment of the present invention, the housing  10  vertically extends along the inner wall surface of the sidewall  12  and has a housing groove  15 , which is provided so as to face the sidewalls  11  and  12 , as housing space to house the first terminals  20  and the second terminals  30  (see also  FIG. 4 ). More specifically, the housing groove  15  extends in the vertical direction from an upper end of the housing  10  to a the lower end, and extends in the facing directions from the inner wall surface of the sidewall  12  to under the attachment hole  11 A of the sidewall  11 , so as to have a generally L-shape as a whole (see also  FIG. 4 ). 
     The housing groove  15  communicates with the receiving groove  14  and has a lower opening, and houses the first terminals  20  and the second terminals  30  from the lower opening. The lower opening communicates to the attachment holes  11 A and  12 B. The groove width of the housing groove  15 , i.e. the dimension in a direction orthogonal to the paper surface, will be described later. 
     Each of the first terminals  20  is made by punching sheet metal while keeping its plate surface. As shown in  FIGS. 3(A) and 3(B) , each first terminal  20  includes a flexible first elastic arm portion  22 , which extends leftward and then upward and has a generally L-shape, a straight support arm portion  23 , which extends upward from a basal section  21  of the first elastic arm portion  22 , and a first connecting section  24 , which extends downward from the basal section  21 , then rightward and extends outside the housing  10  forming a crank-shape. It is noted that the first connecting section  24  of the first terminal  20  extends outside the sidewall  11  (the right side in  FIGS. 3(A) and 3(B) ). 
     In the embodiment of the present invention, the first elastic arm portion  22  comprises a generally horizontal part, which extends leftward from the basal section  21 , and a generally vertical part, which extends upward from the left end of the generally horizontal part, which is closer to the sidewall  12  than the receiving groove  14 . The first elastic arm portion  22  has, at its upper end of the vertical part, a first contact section  22 A for elastically contacting with the signal circuit section of the flat conductive member P, so as to protrude inside the receiving groove  14  toward the inserted flat conductive member P (see also  FIGS. 6(A) and 6(B) ). 
     The support arm portion  23  includes at its upper end part a rotary support section  23 A, which is opened leftward to be a round concave shape. As will be described, the rotary support section  23 A freely rotatably supports the rotary shaft  42  of the pressing member  40 . The support arm portion  23  has a pressing protrusion  23 B formed to protrude from the left edge at a relatively lower position thereof. The first connecting section  24  is provided lower than the bottom portion of the housing  10 , and a lower edge of a portion that extends rightward is designed to be connected by soldering to the signal circuit section (not illustrated) on the circuit board. 
     Once the support arm portion  23  is pressed into the attachment hole  11 A of the sidewall  11  of the housing  10  from thereunder, the pressing protrusion  23 B of the support arm portion  23  latches onto the inner wall surface of the attachment hole  11 A and thereby the first terminal  20  is held by the sidewall  11  near the bottom portion of the housing  10 . 
     In addition, with the first terminal  20  being held by the sidewall  11 , the support arm portion  23  penetrates through the attachment hole  11 A and the upper half portion extends upward from the attachment hole  11 A. Moreover, as shown in  FIGS. 3(A) and 3(B) , the first elastic arm portion  22  has its most part housed in the housing groove  15 , and the first contact section  22 A sticks out from the housing groove  15  to the receiving groove  14 . 
     Similarly to the first terminals  20 , each second terminal  30  is made by punching sheet metal keeping the plate surface. As shown in  FIG. 3(A) , each second terminal  30  includes a second elastic arm portion  32 , which extends upward, a straight attachment arm  33 , which extends upward from a left part of the basal section  31  of the second elastic arm portion  32 , and a second connecting section  34 , which extends downward from the left part of the basal section  31  and then extends leftward so as to have a crank-like shape to extend outside the housing  10 . It is noted that the second connecting section  34  of the second terminal  30  extends outside the sidewall  12  (the left side in  FIGS. 3(A) and 3(B) ). 
     As well shown in  FIG. 3(A) , the second elastic arm portion  32  extends tilting to the middle position so as to be gradually away from the sidewall  12  as it goes upward, and then extends being tilted from the bent part near the upper end of the second elastic arm portion  32  so as to approach the sidewall  12  as it goes upward. At the bent part of the second elastic arm portion  32 , there is provided a second contact section  32 A for elastically contacting with the ground bar P 3  of the flat conductive member P, which protrudes into the receiving groove  14  so as to contact with the inserted flat conductive member P (see also  FIGS. 6(A) and 6(B) ). 
     In the embodiment of the present invention, the attachment arm  33  has a pressing protrusion  33 A, which vertically protrudes at a generally center position on the right edge. The second connecting section  34  is provided lower than the bottom portion of the housing  10  and is designed to have the lower end part of the part extending leftward be connected by soldering to a ground circuit section (not illustrated) on the circuit board. 
     The attachment arm  33  is pressed into the attachment hole  12 B of the sidewall  12  of the housing  10  from below, and the pressing protrusion  33 A of the attachment arm  33  latches onto the inner wall surface of the attachment hole  12 B, and thereby the second terminal  30  becomes held by the sidewall  12  near the bottom portion of the housing  10 . The second elastic arm portion  32  has its most part housed in the housing groove  15 , and the second contact section  32 A protrudes from the housing groove  15  into the receiving groove  14 . 
     As shown in  FIG. 3(A) , being closer to the sidewall  12  than the first elastic arm portion  22  of the first terminal  20 , the second elastic arm portion  32  extends higher than the upper end of the first elastic arm portion  22  from the bottom portion of the housing  10 . Moreover, the second contact section  32 A of the second elastic arm portion  32  is provided higher than the first contact section  22 A of the first elastic arm portion  22 . 
     In the embodiment of the present invention, the second terminal  30  is attached to the sidewall  12  from below, and the second elastic arm portion  32  of the second terminal  30  extends upward in the housing groove  15 . In other words, being different from ground members that extend along an outer surface of the sidewall of the housing and are curved being folded back across the upper end as in a conventional one, since the second terminal  30  does not have the curved section that is provided over the upper end of the sidewall  12 , it is possible to reduce the height dimension of the second terminal  30 . 
     Even in the housing  10 , since it is not necessary to form a recess to house the curved section of the ground member as in a conventional one, it is possible to reduce the height dimension of the housing  10 . Furthermore, it is also not necessary to form a portion to secure the second terminal  30  by forming a protrusion from the outer surface of the sidewall  12  as in a conventional one, so that it is also possible to reduce the dimension of the housing  10  in the thickness direction of the sidewall  12 . As a result, it is also possible to reduce the size of the connector  1  in the height direction and the thickness direction. 
     According to the embodiment, since the second elastic arm portion  32  can be made longer within height range of the sidewall  12  by extending to near the upper end of the sidewall  12 , the second elastic arm portion  32  can securely have enough spring length even if the height dimension of the second elastic arm portion  32  is in the height range of the housing  10 . Accordingly, since the second elastic arm portion  32  can easily elastically deform by increasing the spring length of the second elastic arm portion  32 , it is easier to insert the flat conductive member P into the receiving groove  14 . 
     In addition, according to the embodiment, since the first terminals  20  and the second terminals  30  may be attached respectively by pressing from the same direction to the sidewall  12  and the sidewall  13  of the housing  10 , it is possible to easily attach the first terminals  20  and the second terminals  30  to the housing  10  and easily produce even the connector  1 . 
     More specifically, the connector  1  is configured such that both the first terminals  20  and the second terminals  30  are attached to the housing  10  from the bottom portion thereof (in the same direction). Further, the connector  1  is configured such that both the first terminals  20  and the second terminals  30  are arranged at the same positions in the arrangement direction thereof. 
     Furthermore, as shown in  FIG. 3(A) , since the first terminals  20  as signal terminals and the second terminals  30  as ground terminals can be provided being close to each other within the housing space  15  without interposing any member therebetween, such as the housing  10 , it is easy to adjust transmission characteristics of electrical signals. 
       FIG. 4  is a sectional view of the connector  1  shown in  FIG. 3(B) , in which illustration of the first terminals  20  and the second terminals  30  is omitted.  FIG. 5(A)  is a bottom view of the connector  1  shown in  FIG. 3(B) , and  FIG. 5(B)  is a VB-VB sectional view of the connector  1  shown in  FIG. 3(B) . Here,  FIGS. 5(A)  and (B) are a bottom view and a sectional view taken near the first terminals  20  in the terminal arrangement direction, in which illustration of other parts is omitted. 
     The groove width of each generally L-shaped receiving groove  15  in the housing  10  is slightly larger than the thicknesses of the first terminals  20  and the second terminals  30  in the most part (a region R 2  in  FIG. 4 ), and there is a slight gap formed between plate surfaces of the first terminals  20  and the second terminals  30 . These gaps allow the elastic displacement of the first terminals  20  and the second terminals  30  in a direction that is parallel to the plate surface, and the groove&#39;s inner wall surfaces that form each gap are designed to restrict excess displacement of the first terminals  20  and the second terminals  30  more than allowed in a direction that is orthogonal to the plate surface, i.e. the terminal arrangement direction. 
     Furthermore, in a partial region that houses the horizontal part of the first elastic arm portion  22  of each first terminal  20  (a region R 1  in  FIG. 4 ), there is formed a wider gap than the above-described gap of the other area (the region R 2  in  FIG. 4 ) from plate surfaces of the second terminals  30 . More specifically, as shown in  FIGS. 5(A) and 5(B) , the groove&#39;s width S 1  in the region R 1  is set larger than the groove&#39;s width S 2  in the region R 2 . In addition, the groove&#39;s width dimension S 2  is set slightly larger than the plate thickness S 3  of the first terminals  20 . 
     Moreover, the region R 1  includes a region that overlaps with the upper opening of the receiving groove  14  and the lower opening of the receiving groove  15 , if the housing  10  is viewed from upper side. In other words, as shown in  FIG. 4 , the left part of the region R 1  is provided right under the upper opening and right above the lower opening. 
     According to the embodiment, as described above, the region R 1  has larger groove width than the region R 2  and the gap from the plate surfaces of the first terminals  20  in the region R 1  is formed large. The region R 1  includes a region that overlaps with the upper opening and the lower opening. Therefore, when the pressing member  40  is at the open position shown in  FIGS. 3(A) and 3(B) , even if foreign matters such as dust fall and enter from the upper opening of the receiving groove  14 , the dust may fall and then be discharged outside from the lower opening through the left part of the gap in the region R 1 . 
     Accordingly, according to the embodiment, since dust falls and then will be discharged from the housing  10 , dust will not deposit in the receiving groove  14  and in the housing groove  15 . Therefore, it is possible to satisfactorily prevent problems such as short circuit between adjacent terminals due to adhesion of the dust to the first terminals  20  and the second terminals  30 . 
     In addition, if the first connecting section  24  of each first terminal  20  is connected by soldering to a signal circuit section on the circuit board, the solder and the flux may crawl up from the first connecting section  24  towards the first contact section  22 A by a capillary phenomenon. According to the present invention, however, since the gap is formed in the region R 1 , such capillary phenomenon will not take place in such wide gap, and the solder and the flux will not crawl up further. As a result, it is possible to satisfactorily prevent occurrence of poor connection due to adhesion of the solder and the flux to the first contact sections  22 A. 
     As shown in  FIG. 1 , the pressing member  40  is formed to have almost the same dimension as the sidewalls  11  and  12  of the housing  10  in the terminal arrangement direction, and as well shown in  FIGS. 3(A) and 3(B) , the pressing member  40  is provided above the sidewall  11 . The pressing member  40  can pivotally move between the open position where the pressing member  40  extends in the vertical direction as shown in  FIG. 1  and the close position where the pressing member  40  is generally orthogonal to the open position as shown in  FIG. 2 . As shown in  FIGS. 3(A) and 3(B) , the pressing member  40  includes slit-like grooves  41 , as seen in the lower half part when it is in the open position, at the same positions as the first terminals  20  in the terminal arrangement direction. 
     As shown in  FIGS. 3(A) and 3(B) , in each groove  41 , a rotary shaft  42 , whose section taken orthogonally to the terminal arrangement direction is circular, and a rectangular rotary restriction section  43  are integrally formed like an island, and the facing inner wall surfaces of the groove  41  are joined by the rotary shaft  42  and the rotary restriction section  43 . The rotary shaft  42  is freely rotatably supported by the rotary support section  23 A of the first terminal  20 , and works as a rotary shaft of the pressing member  40 . 
     In addition, the rotary restriction section  43  contacts with a tip of the rotary support section  23 A at the close position when the pressing member  40  moves from the open position to the close position (see  FIGS. 6(A) and 6(B) ). As a result, further rotary movement of the pressing member  40  is restricted and the pressing member  40  is kept at the close position. 
     As will be described later, the lower end part of the pressing member  40  at the open position shown in  FIGS. 3(A) and 3(B)  protrudes into the receiving groove  14  at the close position and is formed as the pressing section  44 , which presses the flat conductive member P towards the first contact sections  22 A of the first terminals  20  and the second contact sections  32 A of the second terminals  30  (see  FIGS. 6(A) and 6(B) ). 
     As will be described later, the groove part provided lower than the rotary restriction section  43  of the pressing section  44  at the open position when the pressing member  40  is at the open position forms a communicating groove  45 , which is in the receiving groove  14  and goes through in the vertical direction when the pressing member  40  moves to the close position. At the close position, the communicating groove  45  connects between the receiving groove  14  and the housing groove  15  in the vertical direction (see  FIGS. 6(A) and 6(B) ). 
     As well shown in  FIG. 2 , when the pressing member  40  is at the close position, there are formed lock-in sections  46 , which are linear protrusions that extend in the facing direction of the sidewalls  11  and  12  at the both ends of the pressing member  40 . As shown in  FIG. 1 , the lock-in sections  46  are designed to lock into the locking section  51  of the locking hardware  50 , which will be described later. 
     The locking hardware  50  is made by punching sheet metal and then bending in the plate thickness direction. As shown in  FIGS. 1 and 2 , the locking hardware  50  includes an attaching section (not illustrated) that is to be attached and extends in the vertical direction, and a locking section  51 , which is bent so as to protrude towards inside the connector in the terminal arrangement direction. 
     In the embodiment of the present invention, the locking hardware  50  is attached into the recess  16  by pressing the attaching section into the locking hardware attachment hole (not illustrated), which is formed at a bottom of the recess  16  of the housing  10 , from thereabove. Then, when the pressing member  40  is at the open position shown in  FIG. 1 , the locking section  51  keeps the pressing member  40  at the open position by locking to the lock-in sections  46 , which are formed at the both ends of the pressing member  40 . 
       FIGS. 6(A) and 6(B)  are longitudinal sectional views showing the circuit board electrical connector after the flat conductive member is inserted into the circuit board electrical connector according to the embodiment of the present invention. More specifically,  FIG. 6(A)  is a sectional view of the circuit board electrical connector corresponding to  FIG. 3(A)  and  FIG. 6(B)  is a sectional view of the circuit board electrical connector corresponding to  FIG. 3(B) . Hereunder, referring to  FIGS. 3(A) and 3(B)  and  FIGS. 6(A) and 6(B) , connection between the connector  1  and the flat conductive member P will be described. 
     First, with the pressing member  40  being at the open position shown in  FIGS. 3(A) and 3(B) , insert the flat conductive member P into the receiving groove  14  from thereabove. Once the flat conductive member P is inserted in the receiving groove  14 , a surface of the flat conductive member P (a surface on the left side in FIG.  6 (A)), on which a signal circuit section and the ground bar P 3  are formed, faces the first contact sections  22 A of the first terminals  20  and the second contact sections  32 A of the second terminals  30 . 
     Next, pivotally move the pressing member  40  at the open position to the close position shown in  FIGS. 6(A) and 6(B) . At the close position, the pressing section  44  of the pressing member  40  protrudes into the receiving groove  14 , and presses the flat conductive member P to the first contact sections  22 A of the first terminals  20  and the second terminals  32 A of the second terminals  30 A. As a result, the contact pressure between the first contact sections  22 A and the signal circuit section and the contact pressure between the second contact sections  32 A and the ground bar P 3  are enhanced. 
     According to the embodiment, since the second elastic arm portion  32  of each second terminal  30  is held like a cantilever in its free state, if the pressing member  40  pivotally moves to the close position after insertion of the flat conductive member P and thereby the ground bar P 3  presses the second contact section  32 A, the whole second elastic arm portion  32  itself easily elastically displaces leftward. 
     Then, once the elastic displacement reaches specific amount, as shown in  FIG. 6(A) , the upper end of each second elastic arm portion  32  contacts with an inner wall surface of the sidewall  12  and becomes held at the both end, so that it hardly elastically displaces in comparison with when it is held like a cantilever. As a result, since excess elastic displacement of the second elastic arm portion  32  becomes restricted, it is possible to prevent damages (permanent setting in fatigue) of each second elastic arm portion  32  and to achieve high contact pressure between the second contact section  32 A and the ground bar P 3 . 
     At the close position, as shown in  FIGS. 6(A) and 6(B) , the communicating groove  45  of the pressing member  40  is located in the receiving groove  14 , and the receiving groove  15  and the housing groove  15  communicate to each other in the vertical direction via the communicating groove  45 . Accordingly, even if foreign matters, such as dust, fall and enter from the upper opening of the receiving groove  14 , such dust falls and then will be discharged outside from the lower opening through the communicating groove  45  and the gap in the housing groove  15 . 
     As a result, the dust will not deposit in the receiving groove  14  or in the housing groove  15 . Therefore, it is possible to satisfactorily prevent problems such as short circuit between adjacent terminals due to adhesion of the dust onto the first terminals  20  and the second terminals  30 . In addition, it is also possible to satisfactorily prevent poor connection to the flat conductive member P due to adhesion of the dust to the first contact sections  22 A of the first terminals  20  and the second contact sections  32 A of the second terminals  30 . 
     In the embodiment, the first terminals and the second terminals are made by punching sheet metal, whereas it is also possible to make at least the first terminals or the second terminals by bending strip-like sheet metal in the plate thickness direction. 
     The disclosure of Japanese Patent Application No. 2010-022084, filed on Feb. 3, 2010 is incorporated in the application by reference. 
     While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.