Abstract:
A flat cable connector consisting of a board connector and a cable connector ( 21 ) which comprises a housing ( 22 ) having a plugging section ( 24 ) pluggable to the board connector and a mounting section ( 24 ) having an exposed face ( 37 ) on which the connection section ( 49 ) of a flat cable ( 46 ) is mounted, a terminal ( 23 ) having a board section ( 33 ) for contact with a terminal of the board connector within the plugging section and a cable section ( 34 ) for contact with the conductive pad ( 50 ) of the flat cable ( 46 ) on the exposed face, and a push plate ( 40 ) for pressing down the connection section ( 49 ) of the flat cable ( 46 ) onto the terminal ( 23 ) for keeping electrical conduction between the connection section and the terminal.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to electrical connectors and, particularly, to a flat cable connector for connecting a flexible flat cable (FFC) and a flexible printed circuit board (FPC).  
           [0003]    2. Description of the Related Art  
           [0004]    The flat cable connector consists of a board connector mounted on the FPC and a cable connector that is able to plug into the board connector and to which a flat cable is connected by, for example, soldering. The soldering, however, is labor intensive and not environment-friendly.  
           [0005]    Japanese patent application Kokai No. 8-264239 discloses a connector that needs no soldering. FIGS. 15 and 16 show the cable connector. The cable connector  1  comprises an insulative housing  3  having a lower opening  2  and a plurality of terminals  4  attached to the housing  3  through the lower opening  2 . A board connector (not shown) is plugged through the lower opening  2 . A horizontal slot  6  is provided in a side wall  5  of the housing  3  for receiving a flat cable  7  and a flat actuator  8 . Each terminal  4  has a pair of leg sections  10  extending downwardly along inner faces of the side wall  5  and the opposed side wall  9  and a linking section  11  for linking upper portions of the leg sections  10 . The leg sections  10  should be sufficiently long to establish the effective contact length in terminals between the cable connector  1  and the board connector when they are plugged-in. A cut-out  12  is provided in the linking section  11  to provide a cantilevered flexible arm  13  that extends toward the slot  6 .  
           [0006]    To connect the cable connector  1  and the flat cable  7 , first of all, the flat cable  7  is inserted into the cut-outs  12  through the slot  6  such that the conductors of the flat cable  7  face upwardly and make contact with the flexible arms  13 . Then, the flat actuator  8  is inserted under the flat cable  7  while maintaining the contact between the conductors and the flexible arms  13 . The flat cable  7  is held under pressure between the flexible arms  13  and the flat actuator  8 , thus electrically connecting the terminal  4  and the flat cable  7 .  
           [0007]    However, the flat cable connector  1  requires much labor to attach the flat cable  7  trough the slot  6  and cut-outs  12  because the flat cable  7  tends to warp and the slot  6  and the cut-outs  12  are very thin. Since the contact between the flat cable  7  and the terminals  4  is held by the resilient power of the flexible arms  13 , a pulling force upon the flat cable  7  can cause poor contact or fall of the flat cable  7 . There is a section of connection with the flat cable  7  inside the housing  3  so that the cable connector  1  becomes tall by that much. In addition, the actuator  8  cannot be too thin to avoid breaking. As a result, it has been difficult to reduce the height of the cable connector  1 . Furthermore, in the above connector that the flat cable  7  is held by the terminals  4 , it is impossible to arrange terminals in a zigzag fashion so that the cable connector  1  is not useful for a flat cable having a great number of conductors arranged therein.  
         SUMMARY OF THE INVENTION  
         [0008]    Accordingly, it is an object of the invention to provide a compact flat cable connector that is easy to attach a flat cable having a great number of conductors arranged therein.  
           [0009]    According to one aspect of the invention there is provided a flat cable connector for connecting a flat cable to a printed circuit board, comprising a housing having an exposed face on which a connection section of the flat cable is mounted; at least one terminal provided in the housing and having a board section connectable to a circuit trace of the printed circuit board and a cable section for contact with the connection section of the flat cable; and a push plate for pressing down the connection section of the flat cable onto the terminal on the exposed face for keeping electrical conduction between the connection section and the terminal.  
           [0010]    According to another aspect of the invention there is provided a flat cable connector consisting of a board connector to be mounted on a printed circuit board and a cable connector to be connected to a flat cable, the cable connector comprising a housing having a plugging section pluggable to the board connector and a mounting section having an exposed face on which a connection section of the flat cable is mounted; at least one terminal having a board section for contact with a terminal of the board connector within the plugging section and a cable section for contact with a connection section of the flat cable on the exposed face; and a push plate for pressing down the connection section of the flat cable on the terminal for keeping electrical conduction between the connection section and the terminal.  
           [0011]    It is preferred that the housing comprises a guide plate to form a space between the guide plate and the mounting section into which the push plate is inserted to press down the connection section of the flat cable onto the terminal for electrical conduction. The exposed face may have at least one projected portion that engages a hole of the flat cable. The projected portion may have a conical form or at least one rib on a side wall thereof. The housing may comprise an abutting wall having at least one key groove therein and the push plate may have at least one key portion that is fitted into the key groove. The push plate may have a resilient retention portion and the housing may have at least one engaging portion for engagement with the retention portion so that when the push plate is inserted to a predetermined position, the retention portion engages the engaging portion. The terminal may have a spring arm extending trough the mounting section so that a front end thereof projects from the exposed face for contact with the connection section of the flat cable. The flat cable connector may further comprises a shield plate for covering at least the plugging section of the housing and having a spring arm projecting from the exposed face for spring contact with the push plate.  
           [0012]    By simply pushing the push plate into the housing it is possible to press down the connection section of a flat cable onto the terminal for electrical conduction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a plan view of a housing for a flat cable connector according to an embodiment of the invention;  
         [0014]    [0014]FIG. 2 is a side view of the housing;  
         [0015]    [0015]FIG. 3 is a sectional view taken along line  3 - 3  of FIG. 2;  
         [0016]    [0016]FIG. 4 is a plan view of a push plate for the flat cable connector;  
         [0017]    [0017]FIG. 5 is a side view of the push plate;  
         [0018]    [0018]FIG. 6 is a plan view of a flat cable;  
         [0019]    FIGS.  7 - 11  are sectional views of the flat cable connector;  
         [0020]    [0020]FIG. 12 is a perspective view of part of a flat cable connector according to another embodiment of the invention;  
         [0021]    [0021]FIG. 13 is a perspective view of a flat cable connector according to still another embodiment of the invention;  
         [0022]    [0022]FIG. 14 is a perspective view of a projected portion according to yet another embodiment of the invention;  
         [0023]    [0023]FIG. 15 is a perspective view of a conventional connector; and  
         [0024]    [0024]FIG. 16 is a sectional view of the conventional connector. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    Embodiments of the invention will now be described with reference to the accompanying drawings.  
         [0026]    In FIGS.  1 - 3 , the flat cable connector consists of a board connector (not shown) to be mounted on a PCB and a cable connector  21  pluggable to the board connector. The cable connector  21  comprises an insulative housing  22  and a plurality of terminals  23  press fitted into the housing  22  in two rows in a zigzag fashion. The housing  22  has a rectangular plugging section  24  and a flat mounting section  25  provided on the plugging section  24 . The mounting section  25  has an exposed face  37  on the top. An abutting wall  26  is provided at the rear edge of the exposed face  37  and a plurality of or seven key grooves  27  are provided inside the abutting wall  26 . A pair of front and rear guide plates  28  are provided on opposite sides of the exposed face  37 . A cut-out  29  is provided at the central portion of each guide section  28 .  
         [0027]    A first raised portion  30  is provided on the exposed face  37  under the guide section  28  and a second raised portion  31  is provided under the cut-out  29 . The second raised portion  31  is made lower than the first raised portion  30  by the thickness of the connection section  49  of a flat cable  46  (FIG. 6). A pair of studs  32  are provided on the exposed face  37  and each have a semi-spherical top.  
         [0028]    In FIGS.  7 - 11 , each terminal  23  has a base section  33  that is press fitted into the plugging section  24  and a cable section  34  that is press fitted into the mounting section  25 . Each base section  33  has an elongated shape and is provided vertically along the inner face of the plugging section  24 . A spring arm  35  extends diagonally upwardly from the cable section  34  such that the front end  36  projects from the exposed face  37 . Since the spring arm  35  extends upwardly from the lower portion of the cable section  34 , not only the height of the mounting section  25  is minimized but also damage to the spring arm  25  is prevented when an excessive force is applied upon the spring arm  25 .  
         [0029]    A shield plate  38  covers the housing  22  and, as shown in FIG. 3, an upper part of the shield plate  38  extends through the mounting section  25 , forming a contact portion  39 , which has the same shape as the cable section  34  of the terminal  23 ; i.e., the front end  60  projects from the exposed face  37  but is slightly higher than the front end  36  of the cable section  34  by the thickness of the connection section  49  of a flat cable  46 . As shown in FIG. 7, a lower part  61  of the shield plate  38  is bent into the plugging section  24  so as to contact the shield section of a board connector.  
         [0030]    In FIGS. 4 and 5, a push plate  40  is adapted to be mounted on the exposed face  37 . It is made of a metal sheet and has a rectangular shape with a pair of parallel ridges  41  extending in the longitudinal direction for reinforcement. The parallel ridges  41  are made shorter than the distance between the guide sections  28 . A plurality of or seven key portions  42  are provided on the front edge of the push plate  40  and a pair of cut-outs  43  are provided on opposite sides of the key area. An engaging flange  44  is provided on the rear edge of the push plate  40 . A pair of retention tabs  45  are provided on opposite ends of the push plate  40 . Each retention tab  45  extends diagonally upwardly and rearwardly in cantilever form.  
         [0031]    In FIG. 6, a flat cable  46  is flexible and has a cable body  48  in band form and a pair of widened connection sections  49  on opposite ends. The connection sections  49  are made slightly narrower than the push plate  48 . A plurality of signal circuits  47  are provided on a face of the cable body  48  and a ground plane is provided on the other face of the cable body  48 . A plurality of conductive pads  50  are provided on the connection section  49  in zigzag fashion in two rows. A pair of holes  51  are provided in the connection section  49  at the outer corners for engagement with the projected portions  32 .  
         [0032]    How to connect the flat cable  46  to the cable connector  21  will be described with respect to FIGS.  7 - 11 .  
         [0033]    As shown in FIG. 7, the connection section  49  of the flat cable  46  is inserted into a space under the guide section  28  of the connector  21 , with the ground face faced upwardly. Then, as shown in FIG. 8, the flat cable  46  is brought to a flat position such that the projected portions  32  engage the holes  51  for temporally holding. The connection section  49  is shorter than the distance between the abutment wall  26  and the front-side guide plate  28  and narrower than the push plate  40  so that it is mounted on the second raised portion  31  without difficulty but makes no contact with the contact section  39  of the shield plate  38 .  
         [0034]    Then, in FIGS.  9 - 11 , the push plate  40  is inserted between the guide plates  28  and the first raised portions  30 . Since the first raised portions  30  are higher than the second raised portions  31  by the thickness of the flat cable  46 , the connection section  49  does not interfere with the front portion of the push plate  40  so that the push plate  40  is inserted without difficulty. The flat cable  46 , which is fixed temporally, does not move during the insertion of the push plate  40 . When the push plate  40  is inserted into a predetermined position, with the spring arms  35  are flexed downwardly, the front ends  36  of the spring arms  35  are brought into contact with the respective conductive pads  50  under a predetermined pressure, thus electrically connecting the terminals  23  and the flat cable  46 .  
         [0035]    The projected portions  32  engage the holes  51 , positioning accurately the conductive pads  50  with respect to the cable sections  34  of the terminals  23  so that the conductive pads  50  are brought into contact with the front ends  36  of the board sections  33  without failure. The contact section  39  is flexed downwardly to make contact with the opposite ends of the push plate  40  under a predetermined pressure and the ground face of the flat cable  46  makes contact with the push plate  40  so that cable connector  21  is shielded entirely. At this point, the key portions  42  are fitted in the key grooves  27  and the projected portions  32  engage the holes  51  as well as the retention portions or tabs  45  engage the rear side guide plate  28  and the engaging flange  44  abuts on the front-side guide plates  28  so that the horizontal movement of the push plate  40  is prevented. Also, the upward movement of the push plate  40  is prevented by the guide plates  28  and the key grooves  27 . Consequently, the push plate  40  neither moves out of place nor falls from the housing  22 , thus keeping the conduction between the flat cable  46  and the terminals  23 . Since the contact section  39  is protruded from the front ends  36  by the thickness of the connection section  49  of flat cable  46 , the contact pressure between the push plate  40  and the contact section  39  is kept at an appropriate level and the shield condition of the cable connector  21  is maintained without failure.  
         [0036]    In addition, during the insertion of the push plate  40 , the parallel ridges  41  do not interfere with the guide plates  28  or the other component of the mounting section  25  so that it is not necessary to increase the height of the mounting section  25  by the thickness of the ridges  41 . As a result, by providing the ridges  41  it is possible to reduce the height of the mounting section  25  by the reduction in the thickness of the push plate  40 .  
         [0037]    In FIG. 12, according to another embodiment of the invention, a guide groove  53  is provided in each side wall of the housing  52  to receive an engaging flange  55  of a push plate  54  so that the push plate  54  pushes the connection section  49  of a flat cable  46  on the terminals  23 . The push plate  40  or  54  may take other forms as long as it can press the connection section  49  onto the terminals  23 .  
         [0038]    In FIG. 13, the conductive pads  50  in the above embodiments are replaced by conductive pads (not shown) that are provided on the intermediate portion of a flat cable  57  and the abutment wall  26  is eliminated from the housing  22  such that the conductive pads are connected to the cable connector.  
         [0039]    In FIG. 14, in this embodiment, the projected portion  32  is replaced by a cylindrical column  58  with ribs  59  provided on the side wall to not only absorb an error in engagement with the hole  51  but also prevent play of the flat cable  57  when the flat cable  57  is moved toward the exposed face  37  by the push plate  40  to eliminate the gap between the cylindrical column  58  and the hole  51 .  
         [0040]    The retention portions  45  may take other forms provided on either upper, lower, or side face as far as they can engage the engaging portions that are provided on the mounting section  24  or  56 . The base portion of the engaging flange  44  may be folded back 180 degrees for reinforcement. The plugging structure between the board connector and the cable connector may be modified. Also, the invention may be used for connectors that are attached directly to a board without the use of the board connector.  
         [0041]    As has been described above, according to the invention, a flat cable is attached to the cable connector simply by pushing the connection section of the flat cable with the push plate onto the exposed face of a housing so that the attachment of the flat cable is simplified. In addition, the holes of a flat cable engage the raised portions to temporally fix the flat cable, making the attachment operation easy. The flat cable is held securely at a predetermined position after the push plate is attached so that it neither makes poor contact with the terminals nor falls from the connector.  
         [0042]    The key portions at the front edge of the push plate engage the key grooves of the abutting wall and the retention tabs of the push plate engage the engaging portions of the guide plates so that falling of the push plate is prevented. The spring arms of terminals make it possible to reduce the height of the housing and miniaturize the connector. The plugging section of the housing is covered by the shield plate and the exposed face of the housing is covered by the push plate, and the shield plate and the push plate are brought into contact with each other, the cable connector is shielded simply and surely. The flat cable is placed on the terminals so that there are many design choices including a plurality of rows of terminals arranged.