Abstract:
The connector for a flexible board is equipped with a housing, a plurality of contacts, and a cover. The plurality of contacts are placed so that their contact parts are in two rows along opposing inner wall surfaces of an insertion concavity of the housing. By inserting a pressure-applying part of the cover into the insertion concavity, a flexible printed circuit board (FPC), which has been guided between the cover and the insertion concavity, is pushed in and deformed and held sandwiched between the cover and the insertion concavity, and each contact part of the FPC comes into contact with the contact part of the corresponding contact. The number of contacts capable of being housed within the connector is increased two-fold from that of prior art connectors and the number of contact parts in the flexible board is increased two-fold. Furthermore, operation of the connector is easier.

Description:
INCORPORATION BY REFERENCE  
       [0001]     The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2004-241709 on Aug. 20, 2004. The content of the application is incorporated herein by reference in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to connectors for flexible boards. More specifically, the present invention relates to a flexible board connector for electrically connecting a flexible board, such as a flexible printed circuit board (FPC) or a flexible flat cable (FFC), to a printed circuit board.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the prior art, with this type of flexible board connector, the flexible board is inserted with a low insertion force so that there is no pressure from the contacts during insertion of the flexible board. After insertion of the flexible board, a stable electrical connection is achieved by contacting the contacts with a prescribed pressure. This is known as a zero insertion force construction.  
         [0004]     For example, as shown in  FIGS. 12A and 12B , a housing  103  houses and retains a plurality of contacts  101 . A slider  105  can slide into housing  103 . An operating lever  109  is rotatably supported on housing  103  via reinforcement metal fittings  107 . Operating lever  109  is rotated in a counterclockwise direction, and as shown in  FIG. 12A , slider  105  is moved towards the left so that it is pulled out. In addition, the front side is moved higher than horizontal plane H. After inserting FPC  111  with a low insertion force, operating lever  109  is rotated in the clockwise direction indicated in  FIG. 12A , and slider  105  is moved towards the right. FPC  111  is moved to a prescribed position, and its contact parts contact the contact parts of contact  101  having a prescribed elasticity and are locked (see, for example, Japanese Laid-Open Patent Publication Number 2003-317838).  
         [0005]     However, with the conventional example shown in  FIGS. 12A and 12B , the plurality of contacts  101  that are housed in housing  103  is arranged in one row along a set direction (in  FIGS. 12A and 12B , the front-back direction from the paper surface). As a result, there is a limit to the number of contacts  101  that can be housed in the connector, and therefore it is difficult to increase the number of contact parts of FPC  111 .  
         [0006]     In addition, FPC  111  is inserted when operating lever  109  is rotated in the counterclockwise direction and slider  105  is pulled out, and then after insertion of FPC  111 , operating lever  109  is rotated in the clockwise direction to lock it. This results in a complicated operation.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention takes into consideration the above problems and provides a connector for a flexible board in which the number of contact elements of the flexible board is doubled by doubling the number of contacts that can be housed inside the connector. In addition, the operation is made easier.  
         [0008]     The connector for a flexible board, according to an embodiment of the present invention, includes a housing in which an insertion concavity is formed, a plurality of contacts which are retained in the housing and have contact parts that face the inside of the insertion concavity, and a cover having a pressure applying part which can be inserted into and removed from the insertion concavity. The plurality of contacts have their contact parts arranged in two rows along opposing inner walls of the insertion concavity. By inserting the pressure applying part into the insertion concavity, a flexible board which has been guided to between the cover and the insertion concavity is pushed and deformed and is held interposed between them, and a contact part of the flexible board is brought into contact with a contact part of a corresponding contact.  
         [0009]     Thus, the present invention provides a flexible board connector equipped with a housing, a plurality of contacts, and a cover, in which the plurality of contacts have their contact parts arranged in two rows along opposing inner walls of the insertion concavity. By inserting the pressure applying part into the insertion concavity, a flexible board which has been guided to between the cover and the insertion concavity is pushed and deformed and is held interposed between them, and a contact part of the flexible board is brought into contact with a contact part of a corresponding contact. Because of this construction, the number of contacts that can be housed in the connector is doubled, and the number of contact parts (contact pads for example) of the flexible board can be doubled. In addition, there is no need for a rotating operation, and the operation is improved.  
         [0010]     Protruding pieces used for positioning can be formed on the flexible board; and the protruding pieces can be shaped to approximately overlap with areas on the surface at both ends of the insertion concavity when the flexible board is guided between the cover and the insertion concavity. Positioning parts can be provided on the housing which join with the edges of the protruding pieces and position the flexible board.  
         [0011]     With a flexible board connector as described above, protruding pieces are formed on the flexible board. Positioning parts are formed on the housing. The protruding pieces are shaped to approximately overlap with areas on the surface at both ends of the insertion concavity when the flexible board is guided between the cover and the insertion concavity. Positioning parts join with the edges of the protruding pieces and position the flexible board. Because of this construction, the positioning of the flexible board with respect to the housing is done easily.  
         [0012]     The positioning parts can include insertion stoppers which stop insertion of the flexible board by coming into contact with a front edge of the protruding pieces of the flexible board and joining protrusions which provisionally position the flexible board by joining with a back edge of the protruding pieces.  
         [0013]     With a flexible board connector as described above, the positioning parts are formed from insertion stoppers and joining protrusions. Insertion stoppers stop insertion of the flexible board by coming into contact with the front edge of the protruding pieces of the flexible board. Joining protrusions provisionally position the flexible board by joining with a back edge of the protruding pieces. As a result of this construction, the positioning of the flexible board with respect to the housing is easy and accurate.  
         [0014]     Joining tabs can be formed on the cover at positions on both sides of the pressure-applying part, and together with the pressure applying part, the joining tabs can join with the surface of the protruding pieces during insertion of the pressure applying part into the insertion concavity.  
         [0015]     With a flexible board connector as described above, joining tabs are formed on the cover at positions on both sides of the pressure-applying part. During insertion of the pressure applying part into the insertion concavity, the joining tabs, together with the pressure applying part, join with the surface of the protruding pieces. As a result of this construction, by inserting the pressure applying part into the insertion concavity, the flexible board which is sandwiched between the cover and the insertion concavity is prevented from slipping out. In addition, positioning of the flexible board and the contact parts of the corresponding contact is done reliably.  
         [0016]     Arms can be provided on the cover which face the outer wall surface of the housing when inserting the pressure applying part into the insertion concavity. Hooks can be formed on the outer wall of the housing and the opposing wall of the arms and can join with each other during insertion and removal of the pressure applying part to prevent slipping. Positioning protrusions can be formed on at least one of the surfaces of either the outer wall of the housing or the opposing wall of the arms for positioning during insertion and removal of the pressure applying part with respect to the insertion concavity.  
         [0017]     With a flexible board connector as described above, arms are formed on both sides of the cover, and hooks are formed on the outer wall of the housing and the opposing surface of the arms. On at least one of the surfaces of either the outer wall of the housing and the opposing surface of the arms, positioning protrusions are formed. This prevents the pressure applying part from slipping out during insertion and removal and positions the pressure applying part with respect to the insertion concavity during removal and insertion. As a result of this construction, the operation of guiding the flexible board between the cover and the insertion concavity and the operation of insertion and removal of the cover with respect to the insertion concavity are made easier, and the operation is improved.  
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0018]     The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of the illustrative embodiments of the invention wherein like reference numbers refer to similar elements and in which:  
         [0019]      FIG. 1  is an exploded cross-sectional perspective view showing a connector for a flexible board according to an embodiment of the present invention;  
         [0020]      FIG. 2A  is a cross-sectional plan view of the connector of  FIG. 1  with a section omitted;  
         [0021]      FIG. 2B  is a cross-sectional front view of the connector of  FIG. 1  with a section omitted;  
         [0022]      FIG. 3A  is a bottom view of the connector of  FIG. 2A ;  
         [0023]      FIG. 3B  is a right side view of the connector of  FIG. 2B ;  
         [0024]      FIG. 3C  is a cross-sectional side view along line A-A of the connector of  FIG. 2A ;  
         [0025]      FIG. 4A  is a plan view of a housing of the connector of  FIGS. 1-3  with a section omitted;  
         [0026]      FIG. 4B  is a cross-sectional front view of the housing of  FIG. 4A  with a section omitted;  
         [0027]      FIG. 5A  is a bottom view of the housing of  FIG. 4A ;  
         [0028]      FIG. 5B  is a right side view of the housing of  FIG. 4B ;  
         [0029]      FIG. 5C  is a cross-sectional side view along line A-A of the housing of  FIG. 4A ;  
         [0030]      FIG. 6A  is a plan view of a cover of the connector of  FIGS. 1-3  with a section omitted;  
         [0031]      FIG. 6B  is a cross-sectional front view of the cover of  FIG. 6A  with a section omitted;  
         [0032]      FIG. 7A  is a bottom view of the cover of  FIG. 6A ;  
         [0033]      FIG. 7B  is a right side view of the cover of  FIG. 6B ;  
         [0034]      FIG. 7C  is a cross-sectional side view along line A-A of the cover of  FIG. 6A ;  
         [0035]      FIG. 8  is a plan view showing a FPC guided between a housing and a cover according to an embodiment of the present invention;  
         [0036]      FIG. 9A  is a cross-sectional side view showing a FPC guided between a housing and a cover;  
         [0037]      FIG. 9B  is a cross-sectional side view showing the elastic contact of a FPC and a contact part of a contact by a pressure applying part of a cover;  
         [0038]      FIG. 10  is a partial perspective view showing protruding pieces of a FPC being pressed and bent by a pressure applying part and joining tabs of a cover and being positioned to a prescribed position inside joining concavities of a housing;  
         [0039]      FIG. 11  is a plan view showing a FPC guided between a housing and a cover according to another embodiment of the present invention;  
         [0040]      FIG. 12A  shows a cross-sectional side view of a conventional connector prior to locking; and  
         [0041]      FIG. 12B  shows a cross-sectional side view of the conventional connector of  FIG. 12A  after locking. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]     Referring to  FIGS. 1-3 , there is shown one embodiment of the connector for a flexible board of the present invention. In these figures, there is a housing  10 , a cover  30 , a contact  50 , and as one example of a flexible board there is a FPC  70 .  
         [0043]     Housing  10  is formed from insulating synthetic resin. As shown in  FIGS. 4A, 4B ,  5 A, and  5 B, housing  10  has an opening on the upper surface to form an insertion concavity  11 . Housing  10  is formed approximately as an oblong box-shape.  
         [0044]     On side walls  12  along the length direction of housing  10 , a plurality (for example, 90-100) of contact insertion holes  13  is formed at a prescribed pitch in two parallel rows (for example, 45-50 in each row at a pitch of 1.25 mm).  
         [0045]     Contact insertion holes  13  vertically penetrate side walls  12  of housing  10  and are also open towards the interior of insertion concavity  11 . In one part of each contact insertion hole  13 , there are latching grooves  14  for latching with contact  50 .  
         [0046]     Side walls  15  are the walls along the cross-direction of housing  10 . Joining concavities  16  are formed to the inside of side walls  15  in an area corresponding to the sides of insertion cavity  11 . On the outer wall surface of side walls  15 , there are hooks  17  and positioning protrusions  18 .  
         [0047]     Hooks  17  protrude as hooks to the outside from the upper end of side walls  15 . As shown in the plan view of  FIG. 4A , they are positioned on the upper side (the upper side of  FIG. 4A ). Positioning protrusions  18  are formed protruding towards the outside from the central part of side walls  15 . As shown in the plan view of  FIG. 4A , they are positioned on the lower side (the lower side of  FIG. 4A ).  
         [0048]     Both ends of side walls  12  protrude outward from the wall surfaces of side walls  15 , and side walls  12  and side walls  15  form C-shaped and reverse C-shaped joining concavities  19 .  
         [0049]     In an area which is at the upper part of both sides of side walls  12  and is opposite the upper part of joining concavities  16  and  19 , insertion stoppers  21  and joining protrusions  22  are formed. Insertion stoppers  21  and joining protrusions  22  form positioning parts. As shown in the plan view of  FIG. 4A , insertion stoppers  21  are positioned on the upper side (the upper side of  FIG. 4A ), and the protruding length is longer than joining protrusions  22 . Joining protrusions  22  are positioned on the lower side.  
         [0050]     Cover  30  is formed from insulating synthetic resin. Cover  30  is formed so that it joins with insertion concavity  11  of housing  10  and covers the opening part of insertion concavity  11 . Referring to  FIGS. 6A, 6B , and  7 A- 7 C, cover  30  has a cover body  31 , attachment side piece  32 , pressure applying part  33 , joining tabs  35 , and arms  36 .  
         [0051]     Cover body  31  is formed in an oblong rectangular shape which covers a large proportion of insertion concavity  11 .  
         [0052]     Attachment side pieces  32  extend outward from both ends in the length direction of cover body  31  and are formed in a rectangular shape which covers the openings of joining concavities  16  and  19  of housing  10 .  
         [0053]     Pressure applying part  33  protrudes downward from the lower surface of cover body  31  and a portion of attachment side pieces  32 . Pressure applying part  33  is formed so that it can join with insertion concavity  11  of housing  10 .  
         [0054]     Joining tabs  35  protrude downward from the lower side of attachment side pieces  32  and are positioned on either side of pressure applying part  33 . Joining tabs  35  are formed so that they join with the corresponding part of joining concavities  16 .  
         [0055]     Arms  36  protrude downward from the lower side of attachment side pieces  32  and are formed to join with joining concavities  19 . When arms  36  are joined with joining concavities  19 , the area opposite hooks  17  are thinner than the area opposite protrusions  18 . The ends of arms  36  are provided with hooks  37  which protrude inward.  
         [0056]     Contacts  50  are formed by stamping or bending a conductive metal plate, as shown in  FIGS. 1-3 . Contact  50  has an attachment piece  51  which is formed as a long thin strip, a movable piece  52  which extends from one end of attachment piece  51  and is bent back towards the interior, and a connecting piece  53  which extends from the other end of attachment piece  51  and is bent roughly at a right angle towards the exterior.  
         [0057]     At the end of movable piece  52 , a contact part  55  is formed. On both sides of attachment piece  51 , there are latching protrusions  56 .  
         [0058]     As shown in  FIG. 8 , FPC  70  has a main board body  71  which is formed from a base material such as polyester film, a plurality of contact parts  72  (for example, 45-50 in one row and 90-100 in two rows), and a circuit pattern  73  which is connected to each contact part  72 .  
         [0059]     At either end of main board body  71 , protruding pieces  75  are provided to join with the upper part of joining concavities  16  of housing  10  at the time of insertion into the connector.  
         [0060]     The plurality of contact parts  72  are positioned symmetrically with respect to a center line  76  of protruding pieces  75 .  
         [0061]     Next, referring to  FIGS. 9A and 9B , the assembly method of the connector is described.  
         [0062]     Contacts  50  are built into the inside of housing  10  by inserting contacts  50  into contact insertion holes  13  of housing  10  from its bottom side.  
         [0063]     At this time, when inserting contact  50  into contact insertion hole  13 , latching protrusions  56  of attachment piece  51  are pushed and latched into latching grooves  14 . The end of movable piece  52  protrudes out into insertion concavity  11 , and contact part  55  is positioned inside insertion concavity  11 . In addition, connecting piece  53  protrudes to the exterior of housing  10 .  
         [0064]     Next, arms  36  of cover  30  join with joining concavities  19 , and hooks  37  join between hooks  17  and positioning protrusions  18  of housing  10 . Housing  10  is then ready for insertion of FPC  70  as shown in  FIG. 9A .  
         [0065]     When FPC  70  is not inserted, cover  30  is pushed downward, and pressure applying part  33  joins with insertion concavity  11 . In addition, hooks  37  of arms  36  join below positioning protrusion  18  of housing  10 . As shown in  FIGS. 2A, 2B , and  3 A- 3 C, this is a storage condition for cover  30 .  
         [0066]     Next, referring to  FIGS. 8, 9A , and  9 B, the action of the embodiment described above is described.  
         [0067]     From the storage condition for cover  30  shown in  FIGS. 2 and 3 , cover  30  is pulled upward so that hooks  37  of arms  36  join with housing  10  between hooks  17  and positioning protrusions  18 . This results in a condition of cover  30  that is ready for insertion of FPC  70 .  
         [0068]     Next, FPC  70  is guided between housing  10  and cover  30  from a prescribed direction (from the bottom of the page in  FIG. 8  and from the left in  FIG. 9A ).  
         [0069]     At this time, protruding pieces  75  of FPC  70  are positioned at the upper part of joining concavities  16  by insertion stoppers  21  and joining protrusions  22  of housing  10 . As shown in the plan view of  FIG. 8 , FPC  70  is positioned so that center line  76  of FPC  70  approximately coincides with center line  26 , which extends in the longitudinal direction of housing  10 . In other words, insertion stoppers  21  contact the front ends of protruding pieces  75  and prevent further insertion. Joining protrusions  22  contact the back ends of protruding pieces  75  and prevent FPC  70  from slipping out.  
         [0070]     Next, cover  30  is pushed downward. Pressure applying part  33  joins with insertion concavity  11 . In addition, hooks  37  of arms  36  join with housing  10  below positioning protrusions  18 . This results in a connected condition as shown in  FIG. 9B  and  FIG. 10 .  
         [0071]     In this connected condition, FPC  70  is pushed and bent into an approximate U-shape by pressure applying part  33 . Contact parts  72  come into elastic contact with the corresponding contact part  55  of contact  50 .  
         [0072]     In addition, when pushing down cover  30  into housing  10 , together with the ends of pressure applying part  33 , joining tabs  35  of attachment side pieces  32  join with protruding pieces  75  of FPC  70 . Protruding pieces  75  are pushed down inside joining concavities  16 . After joining is completed, as shown in  FIG. 10 , protruding pieces  75  are bent into an approximate U-shape. As a result, the contact positions for contact parts  72  and the corresponding contact parts  55  of contacts  50  can be accurately matched.  
         [0073]     In the embodiment described above, with housing  10 , a plurality of contacts  50  are formed in two rows which are symmetrical with respect to center line  26  of housing  10 . FPC  70  also has a plurality of contact parts  72  formed in two rows which are symmetrical with respect to center line  76  of FPC  70 . However, the present invention is not limited to this embodiment.  
         [0074]     For example, as shown in  FIG. 11 , although a plurality of contacts  50   a  on housing  10  are formed in two rows which are symmetrical with respect to center line  26   a , one row is shifted ½ pitch with respect to the other row. Corresponding to this, although FPC  70   a  has two rows of contact parts  72  symmetrical with respect to center line  76   a  of FPC  70   a , one row is shifted by ½ pitch with respect to the other row.  
         [0075]     In the above embodiments, with FPC  70 , circuit patterns  73  are formed separately on the surface (the surface where the contact parts are formed) and undersurface. With FPC  70   a , all of the circuit patterns  73   a  are formed on the surface. However, the present invention is not limited to this embodiment. With FPC  70 , the present invention can have all of the circuit patterns  73  formed on either the surface or undersurface. With FPC  70   a , the circuit patterns  73   a  can be formed separated onto the surface and undersurface, or all of the circuit patterns  73   a  can be formed on the undersurface.  
         [0076]     In the above embodiments, hooks  17  and  37  are formed on the outer wall surface of housing  10  and on arms  36  of cover  30  so that they can join with each other, and a positioning protrusion  18  is formed on at least one of the opposing surfaces. This makes the operation of guiding FPC  70  between cover  30  and insertion concavity  11  easier and makes the insertion and removal operation of cover  30  from insertion opening  11  easier. However, the present invention is not limited to this embodiment. The formation of hooks can be omitted and/or the positioning protrusion can be omitted.  
         [0077]     In the above embodiments, joining tabs  35  are formed on cover  30 , and during insertion of pressure applying part  33  into insertion concavity  11 , joining tabs  35  together with pressure applying part  33  join with protruding pieces  75 . This prevents FPC  70  from slipping out and accurately positions contacts  50  and contact parts of FPC  70 . However, the present invention is not limited to this embodiment. Joining tabs  35  can be omitted.  
         [0078]     In the above embodiments, positioning parts are formed by insertion stoppers  21  and joining protrusions  22 . Insertion stoppers  21  stop the insertion of FPC  70 , and joining protrusions  22  provide provisional positioning. As a result, positioning of FPC  70  is easy and accurate. However, the present invention is not limited to this embodiment, and positioning parts other than insertion stoppers  21  and joining protrusions  22  can be used.