Patent Publication Number: US-8113872-B2

Title: Flat-cable connector, production process thereof, and locking device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2009-292891, filed on Dec. 24, 2009, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments discussed herein are related to a flat-cable connector, a production process of the flat-cable connector, and a locking device. 
     BACKGROUND 
     Conventionally, a flat-cable connector to be connected to a flat cable such as a flexible printed circuit (FPC), a flexible flat cable (FFC), or the like has a structure where a large number of conductor contacts are inserted at a predetermined interval into an insulated housing which has been formed by molding a resin, and arranged and secured. The large number conductor contacts are produced at once by punching a metal plate operating a spring action, for example, a copper plate, etc., by press working. In this case, the surface punched by press working (namely, a fracture surface) defines a contact point of the contact to enlarge friction at the contact portion, and prevent fretting corrosion. 
     However, when the metal plate is formed into a teeth-like shape of a comb, and a predetermined number of contacts are inserted in the insulated housing at once, the pitch of the contacts must be larger than the height of the contacts. Accordingly, in a narrow-pitch connector wherein the fracture surface defines a contact point of the contact, normally, it is not possible to insert a predetermined number of contacts into the insulated housing at once, and the conductor contact must be inserted into the insulated housing one by one. 
     Further, when the conventional flat cable is inserted in the connector, a plurality of conductive pads of the inserted flat cable must be maintained in the condition that the pads are respectively brought into contact with the respective conductor contacts at the connector side. However, there has been no mechanism for securing the flat cable at the insertion position in the connector with a simple configuration so as not to generate fine sliding. Therefore, there is a problem of abrasion between the contact points caused by the fine sliding between the respective conductive pads of the flat cable and the respective conductor contacts of the connector. 
     A conductor contact disclosed in JP-A-8-250232 has an insulated housing, a plurality of conductive terminals, and an actuator. The actuator is rotatable between a plane substantially perpendicular to the surface where the contacts are juxtaposed and a plane parallel to the juxtaposed surface. The flat cable is inserted in the actuator under the condition that the actuator is standing so as to be located in the substantially perpendicular plane, and thereafter, the actuator is laid so as to be located in the parallel plane. Thereby, the pressing surface of the actuator presses the contacts to the side of the conductive terminal for securing. 
     A flexible circuit board connector disclosed in JP-A-11-54220 has an insulated housing where two contacts are staggeredly arranged for one pin, and a pressurizing member which can be open or closed with respect to the housing is provided. When the pressurizing member is open, posts located at the opposite end surfaces thereof engage with elastic engagement pieces to prevent removal from the insulated housing. Then, the pressurizing member is closed, while the engagement between the posts and the elastic engagement pieces is released, a locking projection of the pressurizing member engages with the insulated housing to provide a sufficient contact pressure to the flexible circuit board and the contact. 
     In JP-A-8-250232 and JP-A-11-54220, a mechanism which maintains a condition that a plurality of conductive pads of the inserted flat cable are respectively brought into contact with the respective conductor contacts at the connector side, after the flat cable such as FPC, FFC, or the like, is inserted into the connector. However, in the conventional flat-cable connector disclosed in these documents, an actuator and a pressurizing member must be provided to be rotatable with respect to the insulated housing, and thus, a space for rotating these members is required. Further, there is a problem that because the actuator and the pressurizing member are operated, the structure becomes complicated. 
     Also, the conventional flat-cable connector has a structure that the flat cable and the contact are pressed, and thus, when an external force or vibration is applied, fine vibration or fine sliding may be caused between the flat cable and the contact. Thus, there is a problem that the fretting corrosion between the cable and the contact cannot be sufficiently prevented or decreased. 
     SUMMARY 
     According to an embodiment of the present invention, a flat cable connector includes: an insulated housing; a plurality of conductor contacts regularly arranged in the insulated housing in which a plurality of conductive pads of a flat cable are in contact with the plurality of contacts, respectively, when the flat cable is inserted into the insulated housing. Each of the conductor contacts includes a stationary portion secured to the insulated housing and a movable portion integrally formed with the stationary portion. The movable portion is resiliently moved with respect to the stationary portion. An edge which is formed at an apex of the movable portion is defined as a contact point with the conductive pads of the flat cable when the conductive pads of the flat cable come into contact with the conductor contacts. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the flat-cable connector; 
         FIG. 2  is an enlarged detailed view illustrating the portion A of  FIG. 1 ; 
         FIGS. 3A and 3B  are perspective views of a contact before a bending process; 
         FIGS. 4A and 4B  are perspective views of a contact after a bending process; 
         FIG. 5A  is a side view of a contact after a bending process, and  FIG. 5B  is a partial enlarged view of  FIG. 5A ; 
         FIG. 6  is a perspective view of a contact with a carrier; 
         FIG. 7  is a cross-sectional view of a press-fit portion of a contact; 
         FIG. 8  is a perspective view showing the state before the cable is locked in the flat-cable connector; 
         FIG. 9  is a perspective view showing the state after the cable is locked in the flat-cable connector; 
         FIG. 10A  is a cross-sectional view taken along A-A line of  FIG. 8 , and  FIG. 10B  is a partial enlarged view of  FIG. 10A ; 
         FIG. 11  is a cross-sectional view taken along B-B line of  FIG. 8 ; and 
         FIG. 12A  is a cross-sectional view taken along C-C line of  FIG. 9  and  FIG. 12B  is a partial enlarged view of  FIG. 12A . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a flat-cable connector, a production process of the flat-cable connector, and a locking device according to the embodiments of the present invention will be described with reference to the attached drawings. 
       FIG. 1  is a perspective view of the flat-cable connector according to an embodiment of the present invention, a part of which is broken so that the inside can be viewed.  FIG. 2  is a detail view of the broken portion A of  FIG. 1 . 
     The flat-cable connector  10  according to the embodiment of the present invention includes a housing  20  made of an insulation material such as a resin, etc., and a plurality of (for example, approximately 20 to 100 in one row) conductor contacts  30  which are juxtaposed at a predetermined interval in the housing  20  in the direction Q which is perpendicular to the insertion direction P of the flat cable which is not shown in  FIG. 1 . For example, the arrangement pitch of the conductor contacts  30  is approximately 1.0 mm, and the width of the conductor contact  30  as such is approximately 0.4 mm. 
     Each conductor contact  30  is configured by integrating by a stationary portion  32  secured in the insulated housing  20 , with a movable portion  34  which can be bent with respect to the stationary portion  32  when the flat cable is inserted into the insulated housing  20  and the conductive pad (not shown) of the cable side is brought into contact with the movable portion. Accordingly, in the state that the flat cable is not inserted in the insulated housing  20 , as shown in  FIG. 1 , the movable portion is not in contact with, or bound to the portion of the insulated housing  10 , and can be bent within a predetermined range. 
     As shown in  FIG. 2  and  FIG. 3A  to  FIG. 5A , before the bending process by pressing, each conductor contact  30  substantially linearly extends from the stationary portion  32  to the movable portion  34  ( FIG. 3 ). However, after the bending process, only the stationary portion  32  has the substantially linear shape, and the movable portion  34  is formed into a substantially V shape by a first portion  36  which is bent in a predetermined direction with respect to stationary portion  32 , namely, bent to one side (for example, upper side) in the direction R which is perpendicular to the insertion direction P of the flat cable and the arrangement direction Q of the conductor contact  30 , and a second portion  37  which is bent to the side opposite to the direction R (for example, lower side). Then, an edge portion  35  is formed at the top of the substantially V shape. 
     Here, the edge portion  35  is a portion which functions as a contact point with the conductive pad at the cable side, between a period from the time point that the flat cable is inserted in the insulated housing  20  to initiate contact at the conductive pad (not shown) of the cable side, and the movable portion  34  starts to be bent, and until the insertion of the flat cable is complete and the movable portion  34  is bent by a predetermined amount with respect to the stationary portion  32 . 
     Namely, as shown in detail in  FIG. 3B  to  FIG. 5B , the front side, i.e., the side of the first portion  36 , of the edge portion  35  at the top of the substantially V-shaped movable portion  34  is provided with a notch  35   a  on the upper surface thereof, whereas the back side, i.e., the side of the second portion  37  of the edge portion  35  is provided with a portion  35   b  the upper surface of which has a moderate inclination angle. Further, at the side of the second portion  37 , the upper surface is removed for a predetermined range on the opposite sides to define a portion  35   c  having a narrower upper surface. 
     With this structure, as shown in  FIG. 5B , with respect to the conductor contact  30 , during a stroke of a contact point from the start of contact of the conductive pad (contact surface is represented by S) when the flat cable is inserted until the completion of the insertion, only the edge portion  35  having a comparatively small area of the conductor contact  30  is always brought into steady contact with the contact surface S of the conductive pad of the flat cable. Therefore, fine sliding friction at the contact portion can be effectively prevented. 
     Next, with reference to  FIG. 6  and  FIG. 7 , a production process a flat-cable connector according to an embodiment of the present invention will be explained.  FIG. 6  is a perspective view of a contact with a carrier. 
     First, a contact material having a spring properaty, for example, a metal plate (not shown) of phosphor bronze, beryllium copper, titanium copper, etc., is press-worked, etc., to thereby form a contact with carrier  40  wherein a plurality of contacts are respectively connected to the carrier portion to form a comb-teeth shape as shown in  FIG. 6 . Here, the carrier portion  42  of the contact with carrier  40  holds a plurality of (for example, approximately 3 to 100 in one row) contact portions  44  necessary for one predetermined flat-cable connector  10  so that the contact portions are juxtaposed at a predetermined interval. 
     Then, when the metal plate (not shown) is press-worked to form a comb-teeth shaped contact with carrier  40 , the contact with carriers  40  are subjected to bending processes by a plurality of pressing steps. Thereby, as mentioned above, in the individual conductor contact  30  held by the carrier portion  42 , a stationary portion  32  which is pressure bonded to the insulated housing  20  on the surface perpendicular to the contact arrangement direction Q, and a movable portion  34  which can be bent with respect to the stationary portion  32  when brought into contact with the conductive pad (not shown) of the flat cable are integrally formed, and the edge portion  35  is formed at the top of the movable portion  34 . Likewise, at the time of forming the comb-teeth shaped contact with carrier  40  by press working the metal plate by a plurality of steps, a notched portion  46  defined by a V-shaped or a concave shaped groove is formed on both surfaces or one surface of the respective contact  30  at position closer to the carrier portion  42 . 
     In the next step, the contact with carrier  40  is press fitted in the insulated housing  20  as a lump. In this case, the press-fitting to the insulated housing  20  is performed from the back side of the insulated housing  20  in the direction opposite to the insertion direction P of the flat cable (not shown) into the housing. 
     As shown in  FIG. 6  and  FIG. 7 , the stationary portion  32  of the individual conductor contact  30  has a portion  32   a  where the width is expanded to the opposite sides and where an angled projections  32   b  are provided. In contrast, a portion  21  having a slightly larger groove width is provided at a portion of the insulated housing  20  which defines a lower side of a passage through which the individual conductor contact  30  is press fitted, and which corresponds to the stationary portion  32  of the conductor contact  30 . When the contact with carrier  40  is press fitted as a lump into the insulated housing  20 , while all of the conductor contacts  30  are pressed to the downward, the wide width portions  32   a  of the respective conductor contacts  30  are fitted into the groove portions  21  all at once, and at the same time, the projections  32   b  bite into the walls of the groove portions  21  for securing. 
     Accordingly, after the contact with carrier  40  is press fitted and secured in the insulated housing  20 , the carrier portion  42  located at the rearward of the insulated housing  20  is cut off at the notched portion  46 . Thereby, electrical continuity between the respective conductor contacts  30  is discontinued. Then, the flat-cable connector  10  is deemed as being complete. In accordance with need, necessary treatments may be performed to the respective terminal portions  30   a  ( FIG. 1 ) extending to the backward of the insulated housing  20  in order to mount the connector  10  onto a desired printed circuit substrate (not shown). For example, for the surface mounting (SMT) on a conductive pad (not shown) provided on the printed circuit board to correspond to the contact  30 , a bending process to make the tip end of terminal portion  30   a  correspond to the printed circuit substrate surface, a folding process to fold the terminal portion  30   a  to the back side of the insulated housing  20 , etc., are applied. 
     Next, a locking mechanism of the flat-cable connector according to an embodiment of the present invention will be explained.  FIG. 8  is a perspective view showing the state before the flat cable is locked to the connector.  FIG. 9  is a perspective view showing the state after the flat cable is locked to the connector.  FIG. 10A  is a perspective view showing a cross section taken along A-A line of  FIG. 8 , and  FIG. 10B  is a partly enlarged view thereof.  FIG. 11  is a cross sectional view taken along B-B line of  FIG. 8 .  FIG. 12A  is a cross sectional view taken along C-C line of  FIG. 9 , and  FIG. 12B  is a partial enlarged view thereof. 
     The connector  10  has the similar structure as the aforementioned structure shown in  FIG. 1  to  FIG. 7 , and thus, redundant explanations may be omitted. Hereinafter, the explanation regarding is the structure and operation of the flat cable having a guide member and the locking mechanism is mainly described. 
     The flat cable  60  is formed by a flexible flat cable (FFC), a flexible printed circuit substrate (FPC), or the like (in the present specification, generally referred to as “flat cable”). The flat cable  60  provided, for example, at its tip portion, and on one or both surfaces (here, only the rear surface), with a plurality of conductive pads (not shown) which are arranged corresponding to the arrangement of the contacts  30 . At the tip portion of the flat cable  60  and on the surface (here, the upper surface) opposite to the surface provided with the conductive pads  62 , a guide member  50  formed by a resin, etc., is attached by an adhesive agent, etc., and integrated with the flat cable  60 . 
     On the upper surface of the guide member  50 , two convex portions  52  are arranged in the width direction at a predetermined interval. The two convex portions  52  are respectively formed in flat recesses  54 . The guide member  50  has a shape which can be inserted from a cable insertion opening  20   a  of the insulated housing  20  of the connector  10 . The convex portion  52  has a substantially trapezoidal cross section. 
     On the other hand, the insulated housing  20  of the connector  10  is provided with two molded springs  24  having openings (or concave portions) which engage with the convex portions  52  of the guide member when connection between the flat cable  60  and the connector  10  is complete. The molded springs  24  are made of two thin portions  24   a  formed on the upper wall of the insulated housing  20 , and substantially U-shaped slits  26  are formed along the periphery of the thin portions  24   a . The portion within the substantially U-shaped slit  26  defines the molded spring  24 . Then, a free end side of the molded spring  24  has a slightly thick portion extending from its lower side, and an opening  28  is formed at this portion. As mentioned above, the insulated housing  20  is produced by injection molding, etc., of a resin. Because the substantially U-shaped slit  26  is provided, the portion surrounded by the slit  26 , i.e., a portion of the resin molded body, can be elastically bent with respect to the other portions of the insulated housing  20 . In the present specification, this portion is referred to as a molded spring  24 . 
     Therefore, when the flat cable  60  is inserted into the insertion opening  20   a  of the insulated housing of the connector  10 , from the time point when each conductive pad  62  of the flat cable  60  is brought into contact with the edge portion  35  of the contact  30 , the substantially V-shaped movable portion  34  of the contact  30  starts to be bent by a predetermined amount. At the time point when the insertion of the flat cable  60  into the connector  10  is complete, the convex portions  52  of the guide member  50  are fitted into the respective openings  28  of the molded springs  24  of the connector  10  so as to maintain the electrical connection between each conductive pad of the flat cable  60  and each contact  30  of the connector  10 , and to lock the flat cable  60  to the connector  10 . 
     In particular, because the cross section of the convex portion  52  is substantially trapezoidal, once the flat cable  60  is locked to the connector  10 , even if some sort of external force is applied or vibration is transmitted to the flat cable  60 , the connector  10 , or the like, the connection between the flat cable  60  and the connector  10  would not receive influence from the external force, vibration, etc. Therefore, the sliding abrasion between the edge portion  35  of each contact  30  and the conductive pad of the flat cable  60  can be avoided, or can be extremely reduced. 
     Upon removing the flat cable  60  from the connector  10 , when the guide member  50  is pulled out from the insulated housing  20  of the connector  10 , the engagement between the convex portion  52  of the guide member  50  and the opening  28  of the molded spring  24  is disengaged, and the connection between each conductive pad of the flat cable  60  and each contact  30  of the connector  10  is released, and then, the flat cable  60  can be removed from the connector  10 . 
     In the above explanation, the guide member  50  is provided with the convex portion  52 , and the molded spring  24  in the insulated housing  20  of the connector  10  is provided with the opening (or concave portion)  28 . However, on the contrary, it is possible to form a concave portion or opening on the guide member  50 , and the convex portion on the molded spring  24 . In either case, the engaging portion and the to-be-engaged portion are constituted so that when the insertion and connection are complete, they are fitted with each other and locked, and upon removing, they are disengaged and unlocked. 
     An embodiment of the present invention has been explained above with reference to the attached drawings. However, the present invention is not limited to the above embodiment. Various forms, changes, modifications, etc., are possible within the sprint and the scope of the present invention. 
     As explained above, the flat-cable connector and its production process, as well as the locking mechanism for the flat-cable connector according to the present invention can be conveniently used for connecting the flat cable to a connector for a flat cable of any types such as FFC of FPC, in particular, a connector secured on the printed wiring substrate. Specifically, only the edge portion of the conductor contact is in contact with the conductive pad of the flat cable, the abrasion caused by the fine sliding therebetween can be prevented. Thus, this can be widely utilized for the connection between the flat cable and the connector on the printed wiring substrate in a fold type mobile phone, information processing device, and the like. 
     All examples and conditional language recited herein are intended for pedagogical objects to aid the reader in understanding the invention and the concepts contributed by the inventors to further the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the invention have been described in detail, it will be understood by those of ordinary skill in the relevant art that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention as set forth in the claims.