Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to FPC connectors, and more particularly to a FPC connector that interconnects two lengths of the cable in a stacked fashion. 
         [0002]    Connectors for connecting two flat sheet-like cables such as flexible printed circuits (FPC), flexible flat cables (FFC) are known as shown by Japanese Patent Laid-Open (Kokai) No. H 10-189185. 
         [0003]      FIG. 8  is a perspective view illustrating such a conventional FPC connector. This connector includes a housing  301  made of an insulating material a plurality of conductive terminals  302  held in the housing  301 . The terminals  302  are press-fit into terminal mounting holes formed in opposite sides (front-left side and right-back side in the drawing) of the housing  301 . The terminals  302  have cantilever-like contact portions (not shown) extending from the external side of the housing  301  towards the center thereof, and onto the top sides of the contact portions of FPC cables inserted into the connector. 
         [0004]    Locking levers  303  and  304  are rotatably attached to the housing  301 , and rotate about 90 degrees around a revolving shaft. In  FIG. 8 , the locking levers  303  and  304  are shown in locked positions parallel to a top plate  305  of the housing  301 . 
         [0005]    When the FPC cables are connected, the locking levers  303  and  304  are rotated upwardly and then the ends of the FPC cables are inserted into slits on both sides of the housing  301 . Once the FPC ends are inserted, locking levers  303  and  304  are rotated to lock in place as shown and parallel to the top plate  305 . This forces the conductive lines of the FPC cables to contact the contact portions of the terminals  302 . The two FPC cables are thereby connected via the terminals  302  to conductive traces on a circuit board (not shown) to which the terminals  302  are soldered. 
         [0006]    However, since the conventional connector is formed so that the terminals  302  may be attached to the housing  301  having an almost symmetric shape from both sides thereof, and the flat sheet-like cables may be inserted from right and left sides of the housing  301 , the housing  301  is complex in shape, and grows in size. This causes the structure of a metallic mold for forming the housing  301  to become complex and expensive and the mass productivity to decline. In order to connect the two FPC cable ends to each other, it is necessary to connect the terminals  302  to each other from both sides via the conductive trace of the circuit board, this causes workability to decline. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of the present invention, by solving the problems of the conventional connector, to provide a connector with a housing having a pair of cable insertion openings arranged in the same direction, a pair of actuators, and terminals fitted in common into the cable insertion openings which enable the actuators to actuate independently, the connector enabling a simple to manufacture structure of each member thereof and easy to assemble members resulting in high mass productivity. 
         [0008]    Therefore, a connector according to the present invention is a relay connector containing a housing provided with a pair of cable insertion openings or slots, into which ends of pair of circuit substrates such as, FPC are inserted, terminals are fitted into the cable insertion openings, and a pair of actuators capable of movement between a first position in which insertion of the FPC cable ends is possible, and a second position in which the contacts of the FPC cables and the terminals are connected together, wherein the pair of cable insertion openings open in the same direction, the terminals are common to the pair of cable insertion openings, and the actuators are movable independently from each other. 
         [0009]    In another aspect of the connectors of the present invention, each terminal includes first and second contact beams being disposed on opposite sides of the FPC, within cable insertion openings wherein the first and second contact beams include projections into the cable insertion openings which oppose each other. 
         [0010]    In yet another aspect of the connectors of the present invention, each terminal further has a symmetrical shape centered about a straight line interposed between the pair of cable insertion openings. 
         [0011]    In still a further aspect of the present invention, each of the terminals further includes two pairs of first and second contact beams that are joined together by a mounting portion that extending along an axis of symmetry and which fixes the terminal to the housing, and wherein all portions of the terminals are located inside of the housing. 
         [0012]    According to the present invention, a FPC connector contains a housing including a pair of cable insertion openings which open in the same direction, a pair of actuators, terminals disposed in the pair of cable insertion openings, and independently operating actuators. This enables the structure of the connector to be simple and manufactured and assembled together easily, resulting in reduced cost and efficient high mass production. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view (partially in section) showing a connector constructed in accordance with the principles of the present invention; 
           [0014]      FIG. 2  is a perspective view of the connector of  FIG. 1  taken from a different angle; 
           [0015]      FIG. 3  is a cross-sectional view of the connector of  FIG. 1  and showing that actuators thereof in their open position; 
           [0016]      FIG. 4  is the same view as  FIG. 3 , but with an FPC cable inserted into the top cable-receiving opening; 
           [0017]      FIG. 5  is the same view as  FIG. 4 , but with the actuator closed on the FPC cable; 
           [0018]      FIG. 6  is the same view as  FIG. 5 , but showing an FPC cable inserted into the bottom cable insertion opening; 
           [0019]      FIG. 7  is the same view as  FIG. 6 , but showing the bottom actuator closed on its FPC cable; and, 
           [0020]      FIG. 8  is a perspective view of a conventional FPC connector. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]    In the drawings, reference numeral  10  represents a connector serving as a relay connector according to this embodiment, and is used for electrically connecting two circuit substrates such as flat cables  51  to each other. The flat cables  51  are, for example, flexible flat cables referred to as FPC, FFC and so forth, but any types of cables may be acceptable as long as those are flat sheet-like cables provided with conductive lines or traces, including flexible ribbon cables and printed circuit boards. In this embodiment, representations showing directions such as up, down, left, right, front, rear, and the like, to be used for describing the structure and movement of each part of the connector  10  are not absolute, but relative. These representations are appropriate if each part of the connector  10  takes an attitude shown in the drawing figures, however, if the connector  10  changes the attitude thereof, these representations should be understood in amendment according to the change in the attitude of the connector  10 . 
         [0022]    The connector  10  includes a housing  31  provided with a pair of cable insertion openings  33 , or slots, opening in the same direction (to the left of  FIG. 3 ), a pair of movable actuators  11 , and terminals  41  being fitted in common into the pair of cable insertion openings  33 . The housing  31  is formed by molding or the like, an insulating material such as synthetic resin, and functions as a main body of the connector. The housing  31  has a vertically-symmetric structure, and the cross-sectional shape thereof forms a symmetrical shape centering on a center line C-C extending in the lateral direction as the axis of symmetry in  FIG. 3 . 
         [0023]    Each actuator  11  is also formed of an insulating material and functions to fix the free ends of the FPC cables or circuit board to the connector housing. Each actuator  11  is movably attached to the top and bottom of the housing  31 . Each actuator  11  is disposed in the housing  31  for movement between an opened position (a first position) and a closed position (a second position). The terminals  41  are formed of a conductive material such as metal, and preferably formed by means of punching out a metallic plate. Each terminal  41  is also vertically symmetrical around the axis of symmetry C-C ( FIG. 3 ) as shown and is fitted into the upper and lower cable insertion openings  33 . Each terminal  41  is provided with a symmetric shape centering on the straight imaginary axis line C-C between the pair of cable insertion openings  33 . If the connectors in the drawings were rotated 90° clockwise, the connector of terminals would exhibit horizontal symmetry. 
         [0024]    In  FIG. 3 , the housing  31  includes thick plate-like center portions  32  extending in a lateral direction, with thick-plate like top plate portions  35  being disposed on opposite sides of the center portions  32  and extending laterally within the housing. The cable insertion openings  33  are formed between the center portions  32  and the upper and lower top plate portions  35 , and receive the ends of the FPC cables  51  from the front side (left side in  FIG. 3 ). The crosswise dimensions of the upper and lower top plate portions  35  in  FIG. 3  are set to be shorter than the center portions  32 . The center portions  32  and the upper and lower top plate portions  35  are connected together by way of sidewalls  36  disposed on both sides of the housing  31 . 
         [0025]    In the cable insertion openings  33 , a plurality of first terminal-receiving grooves  34   a  and second terminal accepting grooves  34   b  are provided into which the terminals  41  are fitted. The first terminal accepting grooves  34   a  and the second terminal-receiving grooves  34   b  are formed on the surfaces on the side of the top plate portion  35  of the center portion  32 , and on the surface on the side of the center portion  32  of the top plate portion  35 , respectively, and those are situated in the position facing to each other. When the first terminal-receiving grooves  34   a  and the second terminal-receiving grooves  34   b  are described collectively, those will be described as terminal-receiving grooves  34 . For example, about twenty-five of the terminal-receiving grooves  34  are formed with approximately 0.5 mm pitch, and one terminal  41  is fit into each of the terminal accepting grooves  34 . The pitch and quantity of the terminal accepting grooves  34  may be changed as appropriate. Further, the terminals  41  are not always necessary to be fitted into all the terminal accepting grooves  34 , and it is possible to omit the terminals  41  as necessary in response to the arrangement of contact portions of the FPC cables  51 . 
         [0026]    In each of the center portions  32 , a slit or center opening  32   a  is formed and it opens in the same direction as the cable insertion openings  33 , and at the back portion (right of  FIG. 3 ) of the center opening  32   a , there is a terminal fixing hole  32   b  into which a mounting leg portion  47  serving as a mounting portion of the terminal  41  is fitted. The same quantity and the same pitch of the terminal fixing holes  32   b  as those of the terminal accepting grooves  34  are formed, and each of the terminal fixing holes  32   b  and each of the terminal-receiving grooves  34  are situated in the corresponding position. 
         [0027]    Each actuator  11  is a thick plate-like member having an approximate 4-sided shape, and includes a main body  15  operated by an operator with his/her fingers and the like, and an operation portion  16  bulging from the main body  15  is formed so as to be easily grasped with operator&#39;s fingers. In each of the actuators  11 , a plurality of holding holes  12  for receiving actuating levers  44   b  of movable beams  44  of the terminals  41  are formed at the end of the actuator  11  on an opposite side of the operation portion  16 . Shaft portions  17  engage with the actuating levers  44   b  of the movable beams  44  define one surface of the holding holes  12 . The actuators  11  are attached to the housing  31  along the upper and lower rear side edges thereof, and when moved to closed positions, the actuators  11  become almost parallel to the top plate portions  35 , and when opened, the actuators  11  are almost perpendicular to the top plate portions  35 , and the operation portions  16  project above and below the top plate portions  35 . 
         [0028]    Each of the terminals  41  is symmetrical, and includes a main body portion  42  are held in the first terminal accepting grooves  34   a  on both sides of the axis of symmetry, and are joined to each other by a coupling portion  48 . From the main body portions  42 , fixed contact beams  43  extend to the front of the housing  31  as first contact beams. Further, movable contact beams  44  (second contact beams) are connected to the fixed contact beams  43  via coupling beams  45  and extend almost parallel to the fixed contact beams  43  while facing them. The fixed contact beams  43 , the movable contact beams  44 , and the coupling beams  45  cooperatively form an approximate H-letter shape, and are fitted into the cable insertion openings  33  from the rear of the connector. In this case, the fixed contact beams  43  are held within the first terminal accepting grooves  34   a , and the movable contact beams  44  are held within the second terminal accepting grooves  34   b . Then, the flat FPC cable, or circuit board, ends  51  are inserted between the movable and fixed contact beams  43  from the front. As noted above, each terminal  41  is symmetrical and it has two pairs of first and second contact beams, on pair received in the first (or top) cable insertion opening and the other pair received in the second (or bottom) cable insertion opening. 
         [0029]    The coupling portions  48 , mounting leg portions  47  extend to the front of the housing  31  along an axis of symmetry of the terminals  41 . The mounting leg portions  47  are pushed into and fitted in the terminal fixing holes  32   b  from the rear of the housing  31 , thereby fixing the terminals  41  to the housing  31 . Projecting portions are formed on the side surfaces of each of the mounting leg portions  47 , and these projecting portions bite into the inner walls of the terminal fixing holes  32   b , in order to enhance the fixing of the mounting leg portions  47  to the housing  31 . 
         [0030]    Each of the fixed beams  43  includes a tip projecting portion  43   c  projecting from the cutting edge of the fixing beam  43  towards the front of the connector, a cable supporting portion  43   a , also projecting, and being located in the proximity of the tip of the fixing beam  43  and at the rear of the tip projecting portion  43 C, and projecting towards the top plate portion  35 , and a bearing portion  43   b  located at the rear end of the fixing beam  43  and connected to the main body portion  42 . The tip projecting portions  43   c  and approximately linear inner end portions of the main body portions  42  abut the floor surfaces of the first terminal accepting grooves  34   a , in order to fix the fixed contact beams  43  in place. 
         [0031]    The movable beams  44  function as contacts for the contact portions of the FPC cables  51 , and in the proximity of the tips of the movable beams  44 , contact portions  44   a  are formed and they project towards the center portions  32  of the housing into the cable insertion opening. Each of the movable contact beams  44  includes an actuating lever  44   b  which extends at the rear side connected to the coupling beam  45 , and enters the holding hole  12  of the actuator  11  to limit upward movements of the shaft portion  17 . The shaft portion  17  is formed to have an elliptical or rectangular shape in cross section, located between the bearing portion  43   b  and the actuating lever  44   b , to function as a cam by rotation, and to push out the actuating lever  44   b  towards the top plate portion  35 . Once the actuating lever  44   b  is pushed out towards the top plate portion  35 , a portion adjacent to the connecting portion between the movable beam  44  and the coupling beam  45  is deformed elastically, and the entire movable contact beam  44  rotates around a portion adjacent to the connecting portion between the movable beam  44  and the coupling beam  45 . Thereby, the contact tip of the movable beam  44  is moved towards the center portion  32 , and the contact portion  44   a  is pushed into contact with the FPC cable  51 . ( FIG. 4 ) 
         [0032]    As shown in  FIG. 3 , since, when the actuator  11  is in its open position, the shaft portion  17  makes a very small angle that is close to flatness, and each of the actuating levers  44   b  is not pushed out towards the top plate portion  35 , and the tip of the movable contact beam  44  is free and does not move towards the center portion  32 . Consequently, there is a sufficient space between the tip of the movable beam  44  and the tip of the fixing beam  43 , and the end of the flat FPC cable  51 , may be inserted in the cable insertion opening  33  with very little resistance from the contact portion  44   a  and the cable supporting portion  43   a . Therefore, a ZIF (zero insertion force) FPC connector is substantially realized. Each of the terminals  41  does not include any portion projecting outside of the housing  31 . In other words, all portions of the terminal  41  are situated inside the external surface of the housing  31 . 
         [0033]      FIG. 4  is a first view showing an operation for connecting a flat sheet-like cable to the connector according to the embodiment of the present invention.  FIG. 5  is a second view showing the operation for connecting a flat sheet-like cable to the connector according to the embodiment of the present invention.  FIG. 6  is a third view showing the operation for connecting a flat cable to the connector according to the embodiment of the present invention.  FIG. 7  is a fourth view showing the operation for connecting a flat cable to the connector according to the embodiment of the present invention. 
         [0034]    The FPC cable  51  has a plurality of foil-like conductive lines disposed in parallel on an insulating layer showing electrical insulation properties with predetermined pitch, for example, with about 0.5 mm of pitch. The conductive lines are partially covered with an insulating layer. At the end of the flat FPC cable  51  inserted into the cable insertion opening  33 , the top surfaces of the conductive lines are exposed over predetermined length. In  FIGS. 4 through 7 , it is assumed that the conductive lines are exposed on the surfaces of the flat cables  51  facing the top plate portions  35 . Also, accessory plates are attached to the surfaces opposite to the surfaces where the conductive lines at the end portions of the flat cables  51  are exposed. The accessory plates are made of a material with relatively high hardness such as polyimide, and are attached throughout predetermined ranges in the longitudinal direction and the overall ranges in the width direction. 
         [0035]    When the flat FPC cable  51  is connected to the connector  10 , an end portion of the cable is inserted into the cable insertion opening  33  of the housing  31 . As shown in  FIG. 3 , the actuator  11  is situated in its open position in advance. An operator moves an end of one of the flat cables  51  into upper cable insertion opening  33  of the housing  31 , as shown in  FIG. 4 . The flat FPC cable  51  is moved with the accessory plate facing down and the surface on which the conductive lines are exposed facing up. The tip of the flat FPC cable  51  is inserted between the movable contact beams  44  and the fixed contact beams  43  of the terminals  41  which are fitted in the upper cable insertion opening  33  from the front. 
         [0036]    Next, an operator rotates the upper actuator  11  to the closed position as shown in  FIG. 5  by rotating it clockwise. 
         [0037]    This movement causes the shaft portion  17  to rotate so as to push away the space between the bearing portions  43   b  and the actuating levers  44   b  at an angle close to perpendicularity as shown in  FIG. 5 , and to push the rear actuating levers  44   b  up toward the top plate portion  35 . In other words, it pushes the actuating levers  44   b  upward, so the tips of the movable beams  44  move down toward the center portion  32 , and the contact portions  44   a  are pressed against the flat FPC cable  51  so that the conductive lines exposed on the surface of the flat FPC cable  51  abuttingly contact the contact portions  44   a , and thereby connect the FPC conductive lines and the terminals  41  together. The movable beams  44  are elastic and are elastically deformed by being pushed to the flat sheet-like cable  51 , so the connection between the FPC signal lines and the contact portions  44   a  is well maintained. The cable supporting portions  43   a  of the fixing beams  43  face the contact portions  44   a  and the flat cable  51  is reliably supported by the cable supporting portions  43   a , so that connection between the signal lines and the contact portions  44   a  is surely maintained. 
         [0038]    An operator then moves an end of the other flat FPC cable  51  into the cable insertion opening  33  on the underside of the housing  31 . In this case, the flat FPC cable  51  is moved with the accessory plate facing up and the surface on which the conductive lines are exposed facing down (opposite that of the top FPC cable). Thereafter, the end of the flat FPC cable  51  is inserted between the movable and the fixed contact beams  44 , 43  of the terminals  41  which are present in the lower cable insertion opening  33 . 
         [0039]    An operator then operates the lower actuator  11  and moves, the actuator  11  from its open position as shown in  FIG. 6  to the closed position as shown in  FIG. 7 . The bottom actuator  11  is put in its closed position by rotating it counter-clockwise direction. 
         [0040]    This causes the shaft portion  17  to rotate to increase the space between the bearing portions  43   b  and the actuating levers  44   b , and thereby push out the actuating levers  44   b  towards the top plate portion  35  (downward) so that the tips of the movable beams  44  move towards the center portion  32 , and the terminal contact portions  44   a  are pushed against the flat FPC cable  51 . The conductive lines exposed on the surface facing the top plate portion  35  of the flat FPC cable  51 , (on the lower surface of the flat cable  51 ) now abut on the contact portions  44   a , and the conductive lines and the terminals  41  are thus electrically connected together. The movable beams  44  have elasticity and are deformed by being pressed to the flat sheet-like cable  51 , so that connection between signal lines and the contact portions  44   a  is well maintained. The cable supporting portions  43   a  of the fixed contact beams  43  are situated in the position facing the contact portions  44   a , the flat FPC cable  51  is reliably supported by the cable supporting portions  43   a , and connection between the FPC cable and terminals is reliably maintained. 
         [0041]    In this way, when the cables  51  are inserted into the cable insertion openings  33  of the connector  10  in the same direction, a reliable connection is effected whether the circuit substrate is a flexible cable or a more rigid circuit board. 
         [0042]    In the connectors  10  of the invention, it is possible to actuate the pair of actuators  11  independently from each other. Therefore, after having connected one of the flat cables  51  to the connector  10 , it is possible to connect the other flat cable  51  to the connector  10  in a similar manner. This enables an operator to connect the flat cables  51  to the connector  10  in general order with certainty, resulting in the enhancement of easiness, and promptness of connecting operations. Moreover, since it is possible to connect one of the flat cables  51  and the other flat cable to the connector  10  at different times and at different locations, this heightens the flexibility of connecting operations. 
         [0043]    Each of the terminals  41  contains the fixed contact beams  43  and the movable beams  44  disposed on one surface side and the other surface side of the flat FPC cables  51  within the cable insertion openings  33 , wherein the fixed contact beams  43  and the movable beams  44  have cable supporting portions  43   a  and the contact portions  44   a  that face each other. 
         [0044]    Each terminal  41  is symmetrical within the pairs of terminals meaning that they are arranged on opposite sides of a straight line situated between the pair of cable insertion openings  33  and which functions as an axis of symmetry. Without having to connect the terminals  41  to a circuit board and the like, it is possible to connect the flat FPC cables  51  together via the terminals  41 , and to connect the two flat FPC cables  51  together easily. 
         [0045]    Each of the terminals  41  contains the mounting leg portion  47  that also extends along the axis of symmetry and which fixes the terminal  41  to the housing  31 . The entire portions of the terminals  41  are located inside the exterior of the housing  31 . This enables the connector  10  to be handled easily, and to enhance the workability of connecting operations. The portions  48  of the terminal that joins the pairs of contact beams together may also be provided with through-holes tails or surface mount tails (not shown) so that the connector may be mounted to a circuit board and the circuit substrates also connected to traces on the circuit board, adding to the versatility of the use of the connector. 
         [0046]    Since the present invention should not be limited to the above-described embodiment, it is possible to transform the embodiments in various ways based on the gist of the present invention, and these transformations are not eliminated from the scope of the present invention.

Technology Category: h