Patent Publication Number: US-6659794-B2

Title: Connector for connecting FFC

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to a connector to be used for connecting a flexible flat circuit (hereinafter abbreviated as “FFC”) board for use in, e.g., an automobile, on a wiring board. Particularly, the present invention relates to an improvement in connection with reliability and ease of assembly of a connector. 
     2. Description of the Related Art 
     An electrical connector, such as that shown in FIGS. 38 and 39, has hitherto been used as an electrical connector of this type. 
     As shown in FIGS. 38 and 39, reference numeral  51  designates a male connector housing. The male connector housing  51  is constituted of a base member  55 —which serves as a receiver for receiving an FFC  52 —and a fixing member  56 . The base member  55  is provided with a support section  55 - 1  on which the FFC  52  is to be placed, a slit  55 - 3  formed in the support section  55 - 1 , and locating pins  55 - 2 . 
     Attachment of the FFC  52  to the male connector housing  51  is performed by the following operations. Namely, the extremity of the FFC  52  is inserted into the slit  55 - 3  of the base member  55 , and the locating pins  55 - 2  are fitted into holes  52 - 1  of the FFC  52 . 
     Subsequently, the locating pins  55 - 2  of the base member  55  are fitted into holes  56 - 1  of the fixing member  56 . Engagement latches  56 - 2  provided at respective ends of the fixing member  56  are engaged with engagement sections  55 - 5 . 
     Reference numeral  53  designates a female connector housing which is formed from resin through injection molding. Contact terminals  54  are fitted into the female connector housing  53 . 
     The contact terminals  54  are produced from a brass plate through press-molding. A solder tail  54 - 2  is formed at one end of each contact terminal  54  and inserted into and soldered to a through hole formed in a circuit board or a like board (not shown). 
     Two rod-like sections  54 - 3 , each having a contact  54 - 1 , are formed at the other end of each contact terminal  54 . 
     By means of engaging the male connector housing  51  with the female connector housing  53 , lock projections  55 - 4  of the base member  55  are fixedly engaged with engagement recesses  53 - 1  of the female connector housing  53 . As a result, the rod-like sections  54 - 3  of the contact terminal  54  become elastically deformed, and the contacts  54 - 1  of the contact terminal  54  hold a conductor circuit section of the FFC  52 , thereby electrically constituting a predetermined electric circuit. 
     However, in relation to such a related-art male connector housing  51 , the lock projections  55 - 4  are formed on the base member  55 . Hence, when connected to the female connector housing  53 , the male connector  51  is susceptible to horizontal deflections. Engagement between the base member  55  and the FFC  52  is dependent primarily on the FFC  52  and the locating pins  55 - 2  of the base member  55 . Hence, if strong tension is applied to the FFC  52 , the FFC  52  is torn from the neighborhood of the holes  52 - 1  of the FFC  52 . 
     In order to prevent occurrence of a tear, a method of securing the FFC  52  on the base member  55  by means of an adhesive is also employed. However, the method poses a problem of occurrence of a drop in workability. 
     Another problem is that the engagement section  55 - 5  hinders disconnection of the FFC  52  after the male connector  51  has been engaged with the female connector housing  53 . 
     SUMMARY OF THE INVENTION 
     The present invention has been conceived in light of the foregoing problem and aims at providing a connector to be used for connecting an FFC, which connector has high connection reliability and improved ease of assembly. 
     A first configuration for achieving the object is characterized by a connector for connecting a flexible flat circuit (FFC) including a male connector housing having slits along which an FFC is inserted, and a retainer for fastening the FFC to the male connector housing, wherein the retainer is forced into an insertion side of the FFC and engaged with the male connector housing, thereby fastening the FFC between the retainer and the male connector housing in a folded manner. 
     According to a second configuration, the first configuration is characterized in that the slits are formed in a root of each of the guide ribs of the male connector housing. 
     A third configuration is characterized by a connector for connecting an flexible flat circuit (FFC) including a male connector housing having an insertion port along which an FFC is inserted, and a retaining member for fastening the FFC to the male connector housing, wherein the retaining member has slits along which an FFC is inserted and is inserted into and engaged with, at an inclination, the side of the male connector housing opposite to the side thereof into which the FFC is to be inserted, thereby fastening the FFC between the retaining member and the male connector housing in a folded manner. 
     According to a fourth configuration, the third configuration is characterized in that the retaining member can be retained in a temporarily-held state such that an insertion port into which the FFC is to be inserted becomes flush with the slits. 
     A fifth configuration is characterized by a connector for connecting an FFC in which an FFC is sandwiched between a male connector housing and a retainer, wherein the FFC is bent through 180° by the male connector housing and the retainer, to thereby form upper and lower surfaces, and an electrical connection section is formed on the upper and lower surfaces, respectively. 
     According to a sixth configuration, the fifth configuration is characterized in that the FFC is sandwiched between two large and small recessed sections and two large and small projecting sections of the retainer, and a bent portion of the FFC is formed at any point between the male connector housing and a portion of the retainer at which a change arises in the cross section of the retainer. 
     A seventh configuration of the present invention is characterized by a connector for connecting an FFC which includes a plug on which an FFC is to be provided and a housing to be fitted to the plug, wherein the plug has a boss section of small cross section and a seat section of large cross section, which are formed by means of a single upper surface and different lower surfaces of two stages; an engagement member for engaging the FFC is provided on the upper surface, and a projecting section and a recessed section are provided at an interface between the lower surfaces of two stages; an insertion hole and an opening section, which are to be fitted to the boss section and the seat section, are provided in the housing; and a recessed section and a projecting section are provided in a boundary section between the insertion hole and the opening section so as to come into contact with the projecting and recessed sections of the plug with the FFC sandwiched therebetween. 
     According to an eighth configuration of the present invention, the first configuration is further characterized in that a restriction member for restricting the FFC is provided on a lower surface of the seat section of the plug. 
     According to the invention, there is provided an electrical connection connector which constitutes a predetermined electrical circuit by means of fitting a male connector housing having an FFC attached thereto into a female connector housing having a contact terminal incorporated therein, wherein 
     the male connector housing has a storage section which is constituted of a retaining surface for retaining the FFC, a ceiling surface provided at a position above the retaining surface, and guide grooves provided on respective sides of the retaining surface; 
     an engagement projection for meshing with an engagement hole formed in the FFC is provided on the retaining surface; and 
     groove-like warpage spaces are formed in the ceiling surface located at a position above the engagement projection so as to extend from an insertion entrance for the FFC to an end of the storage section. 
     Preferably, one or a plurality of engagement projections are provided, and the projections may be provided in series or in shunt with each other with reference to the direction in which the FFC is to be inserted. 
     The warpage spaces for FFC formed in the ceiling section may assume a C-shaped, U-shaped, or V-shaped cross-sectional profile or other cross-sectional profile, so long as the spaces constrain deformation of the FFC which would be caused by the engagement projection. 
     According to the invention, a shape restriction section is provided on the retaining surface of the male connector housing for restricting and bending an extremity of the FFC downward. 
    
    
     BRIEF DESCRIPTIONS OF DRAWINGS 
     FIG. 1 is a perspective view of a male connector housing according to a first embodiment of the present invention before an FFC is attached to the male connector housing. 
     FIG. 2 is a perspective view of the male connector housing according to the first embodiment after the FFC has been attached to the male connector housing. 
     FIG. 3 is a cross-sectional view of the male connector housing according to the first embodiment before the FFC is attached to the male connector housing. 
     FIG. 4 is a cross-sectional view of the male connector housing according to the first embodiment after the FFC has been attached to the male connector housing. 
     FIG. 5 is a cross-sectional view of a retainer according to the first embodiment after the retainer has been engaged with the male connector housing. 
     FIG. 6 is a cross-sectional view of the male connector housing according to the first embodiment when a female connector housing has been engaged with the male connector housing. 
     FIG. 7 is a cross-sectional view of a male connector housing according to a second embodiment of the present invention. 
     FIG. 8 is a front view of the male connector housing according to the second embodiment. 
     FIG. 9 is a cross-sectional view of the male connector housing before a retaining member according to the second embodiment is engaged with the male connector housing. 
     FIG. 10 is a front view of the male connector housing before the retaining member according to the second embodiment is engaged with the male connector housing. 
     FIG. 11 is a front view of the retaining member according to the second embodiment. 
     FIG. 12 is a cross-sectional view of the retaining member according to the second embodiment. 
     FIG. 13 is a perspective view of a male connector housing according to a third embodiment of the present invention. 
     FIG. 14 is a cross-sectional view of the male connector housing according to the third embodiment. 
     FIG. 15 is a plan view of an FFC according to a fourth embodiment of the present invention. 
     FIG. 16 is a plan view of a plug according to the fourth embodiment. 
     FIG. 17 is a cross-sectional view of the plug shown in FIG.  16 . 
     FIG. 18 is a plan view of a housing according to the fourth embodiment. 
     FIG. 19 is a cross-sectional view of the housing shown in FIG.  18 . 
     FIG. 20 is a plan view of the plug according to the fourth embodiment when an FFC is provided on the plug. 
     FIG. 21 is a cross-sectional view of the plug shown in FIG.  20 . 
     FIG. 22 is a plan view of the connector for connecting an FFC according to the fourth embodiment. 
     FIG. 23 is a cross-sectional view of the connector shown in FIG.  22 . 
     FIG. 24 is a plan view of a plug having an FFC provided thereon according to a fifth embodiment of the present invention. 
     A FIG. 25 is a cross-sectional view of the plug shown in FIG.  24 . 
     FIG. 26 is a cross-sectional view of a connector for connecting an FFC according to a fifth embodiment of the present invention. 
     FIG. 27 is a cross-sectional view of a male connector housing according to a sixth embodiment of the present invention. 
     FIG. 28 is a plan view of a male connector housing according to the sixth embodiment. 
     FIG. 29 is a side view of the connector housing shown in FIG. 27 when viewed from the right. 
     FIG. 30 is a left-side elevation view of the connector housing shown in FIG. 27 when viewed from the left. 
     FIG. 31 is a plan view of an FFC  2  according to the sixth embodiment. 
     FIG. 32 is a descriptive view for describing the FFC  2  according to the sixth embodiment when being inserted into the male connector housing  1 . 
     FIG. 33 is a descriptive view showing the FFC according to the sixth embodiment after having been inserted into the male connector housing  1 . 
     FIG. 34 is a cross-sectional view of a female connector housing according to the sixth embodiment when viewed from the front. 
     FIG. 35 is a plan view of a female connector housing  3  according to the sixth embodiment of the invention. 
     FIG. 36 is a side view of the female connector housing shown in FIG. 34 when viewed from the left. 
     FIG. 37 is a cross-sectional view of the male connector housing and the female connector housing according to the present embodiment when they are engaged with each other. 
     FIG. 38 is a perspective view of a related-art housing and a related-art female connector housing. 
     FIG. 39 is a cross-sectional view of a related-art male connector housing and a related-art female connector housing. 
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     The present invention will be described with reference to the accompanying drawings. 
     First Embodiment 
     FIG. 1 is a perspective view of a male connector housing according to a first embodiment of the present invention before an FFC is attached to the housing. FIG. 2 is a perspective view of the male connector housing according to the first embodiment after the FFC has been attached to the connector housing. FIG. 3 is a cross-sectional view of the male connector housing according to the first embodiment before the FFC is attached to the male connector housing. 
     As shown in FIGS. 1 through 3, reference numeral  1  designates a male connector housing molded from resin through injection; and  2  designates an FFC. Reference numeral  1 - 1  designates a retainer for bending and fastening the FFC  2  to the male connector housing  1 ;  1 - 2  designates a lock to be used for preventing removal of the male connector housing  1  from a female connector housing  3  to be described later; and  1 - 4  designates a plurality of guide ribs to be used when the male connector housing  1  is engaged with the female connector housing  3 . Reference numeral  1 - 7  designates side walls which are provided at the outside of the guide ribs  1 - 4  and have the function of guiding the male connector guide  1  when being inserted into the female connector housing  3 . 
     Reference numeral  1 - 3  designates a slit formed in the root of each of the guide ribs  1 - 4 ; and  1 - 5  designates slits, each being formed in a part of the side wall  1 - 7 . The FFC  2  is inserted into the male connector housing  1  along the slits  1 - 5 . Reference numeral  1 - 6  designates a protuberance for latching the FFC  2 . 
     FIG. 4 is a cross-sectional view of the male connector housing  1  according to the first embodiment after the FFC  2  has been inserted into the male connector housing. FIG. 5 is a cross-sectional view of the male connector housing  1  after the retainer  1 - 1  according to the first embodiment has been latched into the male connector housing  1 . 
     As shown in FIGS. 3 and 4, attachment of the FFC  2  to the male connector housing  1  is completed by means of inserting the FFC  2  into the male connector housing  1  by way of an opening section  1 - 8  until the FFC  2  passes through the slits  1 - 3 ,  1 - 5  and the protuberances  1 - 6  engage with the holes  2 - 1  of the FFC  2  at a position where an extremity  1 - 9  of the slit  1 - 3  comes into contact with the extremity of the FFC  2 . 
     As shown in FIG. 5 the retainer  1 - 1  is fitted into the opening section  1 - 8  of the male connector housing  1  in the insertion direction of the FFC  2  while being folded along a hinge  1 - 10 . Projections  1 - 11  provided at respective ends of the retainer  1 - 1  are engaged with indentations  1 - 12  in the male connector housing  1  (see FIG.  4 ). 
     The FFC  2  is sandwiched between a recessed portion of the male connector housing  1  and a projecting section  1 - 14  of the retainer  1 - 1  in a folded manner. Hence, even when large tensile force is exerted on the FFC  2 , the FFC  2  is not torn from the neighborhood of the holes  2 - 1  of the FFC  2 . 
     Since FFC  2  is inserted while being guided by the slits  1 - 3 ,  1 - 5 , the FFC  2  will not separate from a retention surface  1 - 13  of the male connector housing  1 . Further, the extremity of the FFC  2  is bent downwardly. For this reason, the extremity is not snagged when the male connector housing  1  is engaged with the female connector housing  3 . 
     By virtue of the side walls  1 - 7  and the guide ribs  1 - 4 , which are provided in the male connector housing  1  and act as guides, the male connector housing  1  can be smoothly engaged with the female connector housing  3 . 
     In contrast with the related-art male connector housing, the male connector housing  1  is not divided into two components; that is, a base member  55  and a fixing member  56 . Hence, costs related to parts are reduced, and improved ease of assembly is achieved. 
     Further, through injection molding, the retainer  1 - 1  is formed from resin so as to be integral with the male connector housing  1  via the hinge  1 - 10 . As a result, costs related to components are reduced, and superior workability is achieved. 
     FIG. 6 is a cross-sectional view of the male connector housing  1  according to the first embodiment when engaged with the female connector housing  3 . 
     As shown in FIG. 6, a contact terminal  4  into which a plurality of brass plates have been formed through press-molding is provided in an internal space  3 - 2  of the female connector housing  1 , which is formed from resin through injection molding. One end of the contact terminal  4  is formed into two rod-like sections  4 - 3 , and a contact  4 - 1  is formed at the extremity of each rod-like section  4 - 3 . The other end of the contact terminal  4  has a solder tail to be inserted into and soldered to a through hole of a circuit board (not shown). 
     When the female connector housing  3  is engaged with the male connector housing  1 , the locks  1 - 2  of the male connector housing  1  mesh with projections  3 - 1  of the female connector housing  3 , thus hindering disconnection of the connector housings  1 ,  3 . 
     At this time, the rod-like sections  4 - 3  of the contact terminal  4  become resiliently deformed, and the contacts  4 - 1  pinch a copper foil section of the FFC  2 , thereby establishing electrical continuity and constituting a predetermined electrical circuit. 
     Second Embodiment 
     FIG. 7 is across-sectional view of a male connector housing according to a second embodiment of the present invention. FIG. 8 is a front view of the male connector housing according to the second embodiment. FIG. 9 is a cross-sectional view of the male connector housing before a retaining member according to the second embodiment is engaged with the housing. FIG. 10 is a front view of the male connector housing before the retaining member according to the second embodiment is engaged with the male connector housing. FIG. 11 is a front view of the retaining member according to the second embodiment. FIG. 12 is a cross-sectional view of the retaining member according to the second embodiment. 
     As shown in FIGS. 7 through 12, reference numeral  11  designates a male connector housing;  12  designates an FFC; and  17  designates a retaining member for retaining the FFC  12  in the male connector housing  11 . 
     The male connector housing  11  comprises a lock  11 - 2  provided on an upper surface of the housing; a housing section  11 - 1  which is provided on a lower surface of the housing for housing the retaining member  17 ; an insertion opening  11 - 6 ; an insertion port  11 - 4 ; and a recessed groove  11 - 3  for avoiding occurrence of interference between the male connector housing  11  and a lock projection  17 - 8  of the retaining member  17 . 
     An L-shaped engagement hole  11 - 7  and a semicircular engagement hole  11 - 5  are formed in the side wall  11 - 8  of the male connector housing  11  for holding the retaining member  17 . 
     The retaining member  17  comprises a placement section  17 - 1  on which the FFC  12  is to be placed; a rectangular-parallelepiped engagement claw  17 - 5 ; a semicircular engagement claw  17 - 6 ; a rectangular-parallelepiped temporary engagement claw  17 - 7 ; a projection  17 - 8  to be engaged with the FFC  12 ; and guide ribs  17 - 4  guiding a female connector housing (not shown) when the male connector housing  11  is engaged with the female connector housing. 
     The retaining member  17  is temporarily retained such that a slit  17 - 3  becomes flush with the insertion port  11 - 4  of the male connector housing  11 . 
     As shown in FIG. 9, attachment of the FFC  12  to the male connector housing  11  is performed by the following operations. Namely, the FFC  12  is inserted into the insertion opening  11 - 6  of the male connector housing  11  and passed through the insertion port  11 - 4 . The FFC  12  then enters the slit  17 - 3  of the retaining member  17 , which is temporarily engaged with the male connector housing  11 . When the FFC  12  has come into contact with a tip-end section  17 - 9 , a hole  12 - 1  of the FFC  12  meshes with the lock projection  17 - 8  of the retaining member  17 . 
     Since the insertion port  11 - 4  of the male connector housing  11  is level with the slit  17 - 3  of the temporarily-held retaining member  17 , improved ease of attachment of the FFC  12  is achieved. By means of inserting the retaining member  17  toward an engaging direction (as shown in FIG.  10 ), the engagement claw  17 - 5  engages with the L-shaped engagement hole  11 - 7  of the male connector housing  11 , and the engagement claw  17 - 6  engages with the semicircular engagement hole  11 - 5  of the same. 
     The FFC  12  is lodged, in a collapsed manner, between a recessed portion of the housing section  11 - 1  of the male connector housing  11  and a projecting portion  17 - 2  of the retaining member  17 . Further, when being pulled, the FFC  12  is lodged, in a collapsed manner, more strongly. For these reasons, even when tensile force is exerted on the FFC  12 , a rip does not a rise in the periphery of the lock projection  17 - 8 . 
     The second embodiment employs the retainer  1 - 1  described in connection with the first embodiment as a separate, independent member. Further, in the second embodiment, the retaining member  17  remaining in a temporarily-engaged state shown in FIGS. 9 and 10 is brought into a fully-engaged state shown in FIGS. 7 and 8. Hence, as in the case of the first embodiment, the female connector housing is inserted along the side walls  11 - 8  and the guide ribs  17 - 4 , thus offering improved ease of engagement. There is yielded an advantage of a rip not arising in the periphery of the lock projection even when the FFC  12  is pulled strongly. 
     Since the retaining member  17  can first be set in a temporarily-engaged state, improved ease of assembly is achieved during mass production, thus providing a great advantage. 
     When the male connector housing  11  is engaged with the female connector housing (not shown), rod-like sections of a contact terminal are resiliently deformed, and contacts pinch a copper foil section of the FFC  12 , thereby establishing electrical continuity and constituting a predetermined electrical circuit. 
     Third Embodiment 
     FIG. 13 is a perspective view of a male connector housing and relevant sections according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of the male connector housing according to the third embodiment. 
     In the first and second embodiment, a connection section is provided in the end of the FFC. In contrast, the present embodiment differs from the first and second embodiments in that the connection section is provided outside the end of the FFC, thereby enabling an increase in the density of an electric circuit. 
     As shown in FIGS. 13 and 14, reference numeral  21  designates a male connector housing. A lock  21 - 2  is provided on an upper surface of the male connector housing  21 . Further, the male connector housing  21  is provided with side walls  21 - 3  and guide ribs  21 - 4 , which act as guides when a female connector housing  23  is engaged with the male connector housing  21 . 
     Two layers of recesses are provided in the male connector housing  21 , and release holes  21 - 5  for meshing with projections provided at the extremity of a retainer are formed-in the extremity of the male connector housing  21 . 
     Reference numeral  22  designates an FFC having a predetermined circuit formed thereon; and  22 - 2  designates a copper foil section from which an insulation coating has been peeled. Holes  22 - 1  for locating purpose are formed in the center of the FFC  22 . 
     Reference numeral  25  designates a retainer to be used for pushing and fastening the FFC  22  to the male connector housing  21 . Formed in the retainer  25  are two projecting sections  25 - 1  matching with two recessed sections  21 - 8 , and two projecting sections  25 - 2  matching with two recessed sections  21 - 6 . Further, projections  25 - 4  for locating purpose are provided at the extremity of the retainer  25 . 
     Reference numeral  23  designates a female connector housing. An engagement section  23 - 2  is provided on top of the female connector housing  23  for preventing disengagement of the female connector housing  23  from the male connector housing  21 . A plurality of contact terminals  24  are to be fitted into an internal space  23 - 1 . Each contact terminal  24  has two rod-like sections  24 - 3  and solder tails  24 , and contacts  24 - 1  are provided at the extremities of the rod-like sections  24 - 3 . 
     Attachment of the FFC  22  to the male connector housing  21  is performed through the following steps. As shown in FIG. 14, the projections  25 - 4  provided at the extremity of the retainer  25  are inserted into the holes  22 - 1  of the FFC  22 . Subsequently, the two projecting sections  25 - 1 ,  25 - 2  are fit into the recessed sections  21 - 6 ,  21 - 8  until an end face  21 - 7  of the male connector housing  21  becomes flush with an end face  25 - 6  of the retainer  25 . 
     At this position, engagement claws  25 - 3  provided on respective side surfaces of the retainer  25  are engaged with engagement sections  21 - 1  of the male connector housing  21 , thus hindering disengagement of the retainer  25  from the male connector housing  21 . 
     The FFC  22  is sandwiched, in a bent manner, between raised sections  25 - 2  of the retainer  25  and recessed sections of the male connector housing  21 . Therefore, even when being pulled strongly, the FFC  22  is not susceptible to a rip which would arise from the periphery of the locating holes  22 - 1 . 
     The male connector housing  21  is smoothly engaged with the female connector housing  23  while being guided by the side walls  21 - 3  and the guide ribs  21 - 4 . The lock  21 - 2  of the male connector housing  21  is engaged with the engagement section  23 - 2  of the female connector housing  23 . 
     The two rod-like sections  24 - 3  of the respective contact terminals  24  become elastically deformed, thereby pinching a copper foil section  22 - 2  of the FFC  22  from above and below. The copper foil section  22 - 2  of the FFC  22  is electrically connected to the contacts  24 - 1  over the upper and lower surfaces of the FFC  22 , thereby constituting a predetermined electrical circuit. 
     In addition to the advantages yielded by the first and second embodiments, the present embodiment yields an advantage of the FFC  22  being folded through 180° to constitute electrical contact sections on the upper and lower surfaces of the FFC  22 , thereby enabling an increase in the density of an electrical circuit and rendering the cost of parts lower. 
     The copper foil section  22 - 2  and the locating holes  22 - 1  are formed in several positions on the FFC  22  in the longitudinal direction thereof, by means of peeling off the insulation coating in the same manner as mentioned previously. So long as the male connector housings  21  according to the present embodiment are connected to the thus-peeled portions of the FFC  22 , identical male connector housings  21  are connected in shunt with each other on the FFC  22 . There is yielded an advantage of the ability to constitute a preferred wire harness from a smaller number of parts, by means of using the FFC  22  so as to interconnect circuit units which are to be connected together through multiplex communication. 
     Fourth Embodiment 
     FIG. 15 is a plan view of an FFC according to a fourth embodiment of the present invention; FIG. 16 is a plan view of a plug according to the fourth embodiment; FIG. 17 is a cross-sectional view of the plug shown in FIG. 16; FIG. 18 is a plan view of a housing according to the fourth embodiment; and FIG. 19 is a cross-sectional view of the housing shown in FIG.  18 . 
     As shown in FIG. 15, reference numeral  101  designates an FFC onto which a flexible electrical insulation film and a copper foil are laminated. A predetermined electrical circuit is constituted on the copper foil, and conductor sections  101 - 2  of a connector section are exposed for electrical connection. 
     A plurality of holes  101 - 1  are formed in the FFC  101  so as to be engaged with a plurality of projections  102 - 2  provided on an upper surface of a plug when the FFC  101  is attached to the plug  102 . 
     As shown in FIGS. 16 and 17, reference numeral  102  designates a plug made from resin. The plug  102  has an upper surface  102 - 3 , and a half round section  102 - 6  is provided at one end of the plug  102 . A lower surface of the plug  102  is formed into a two-stage lower surface, and a projecting section  102 - 4  and a recessed section  102 - 9  are provided at an interface between the two stages of the lower surface. 
     Reference numeral  102 - 1  designates a projecting boss having the half-round section  102 - 6 . The boss  102 - 1  is fitted into a housing to be described later. 
     Reference numeral  102 - 5  designates engagement projections which are provided on respective side walls of the plug  102  and are engaged with lances of a housing to be described later. 
     As shown in FIGS. 18 and 19, reference numeral  103  designates a housing made from resin; that is, a connector housing formed from resin through injection molding. A large-diameter opening section  103 - 1  is formed in one end of the housing  103 , and a small-diameter insertion hole  103 - 2  is formed in the other end of the housing  103 . A projecting section  103 - 5  and a recessed section  103 - 6  are formed at a point along the way from the opening section  103 - 1  to the insertion hole  103 - 2 . 
     Lances  103 - 4  are formed in the opening section  103 - 1 . 
     FIG. 20 is a plan view of the plug according to the fourth embodiment when an FFC is provided on the plug, and FIG. 21 is a cross-sectional view of the plug shown in FIG.  20 . 
     As shown in FIGS. 19 and 20, the engagement projections  102 - 2  provided on the upper surface of the plug  102  are engaged with the holes  101 - 1  formed in the extremity of the FFC  101 . The FFC  101  is inserted along the upper surface  102 - 3  of the plug  102  and turned along the semi-half section  102 - 6  provided at the extremity of the plug  102 . The thus-turned FFC  101  is further inserted along a first surface  102 - 7 , the projection section  102 - 4 , and a second surface  102 - 8 . 
     FIG. 22 is a plan view of the connector for connecting an FFC according to the fourth embodiment, and FIG. 23 is a cross-sectional view of the connector shown in FIG.  22 . 
     As shown in FIGS. 22 and 23, the plug  102  having the FFC  101  laid thereon is inserted into the housing  103  by way of the opening section  103 - 1  thereof, and the boss  102 - 1  is fitted into the insertion hole  103 - 2 . The plug  102  is inserted to the extent that the Lances  103 - 4  of the housing are engaged with the projections  102 - 5  of the plug  102 , thereby engaging the Lances  103 - 4  with the projections  102 - 5 . 
     In this position, the projecting section  102 - 4  and the recessed section  102 - 9  of the plug  102  come into contact with the projecting section  103 - 5  and the recessed section  103 - 6  of the housing with the FFC  101  sandwiched therebetween, thus holding the FFC  101 . 
     In this position, the engagement projections  102 - 2  of the plug  102  are housed in notches  103 - 7  formed in the housing. 
     When the plug  102  having the FFC  101  provided thereon is inserted into the opening section  103 - 1  of the housing, the FFC  101  located on the lower surface of the plug  102  does not need to remain in intimate contact with the lower surfaces  102 - 7 ,  102 - 8  of the plug  102 . If the plug  102  is inserted into the opening section while being pulled gently in direction P (shown in FIG.  21 ), the FFC  101  is restricted and housed in a predetermined location, by means of an interior surface of the opening section  103 - 1  of the housing and the lower surfaces  102 - 7 ,  102 - 8  of the plug  102  as the boss  102 - 1  of the plug  102  is inserted into the insertion hole  103 - 2  of the housing. 
     The connector for connecting an FFC shown in FIG. 23 is inserted into a corresponding connector (not shown), and the lock  103 - 3  is engaged with an engagement projection (not shown) of the corresponding connector, thereby constituting a predetermined electrical circuit. 
     In the fourth embodiment, the projecting section  102 - 4  and the recessed section  102 - 9  of the plug  102  come into contact with the projecting section  103 - 5  and the recessed section  103 - 6  of the housing with the FFC  101  sandwiched therebetween, thus holding the FFC  101 . Even when great tensile force is exerted on the FFC  101  in direction P (shown in FIG.  21 ), application of intensive stress to the surroundings of the holes  101 - 1  of the FFC  101  is prevented, and hence no rip arises around the holes  101 - 1 . 
     Projections provided on the upper surface of the plug  102  act as engagement projections having claws at the tip ends thereof. When the plug  102  having the FFC  101  provided thereon is inserted into the opening section  103 - 1  of the housing, the FFC  101  is not disengaged from the engagement projections  102 - 2  of the plug  102 , and hence superior workability is achieved. 
     Fifth Embodiment 
     FIG. 24 is a plan view of a plug having an FFC provided thereon according to a fifth embodiment of the present invention; FIG. 25 is a cross-sectional view of the plug shown in FIG. 24; and FIG. 26 is a cross-sectional view of a connector for connecting an FFC according to a fifth embodiment of the present invention. 
     In contrast with the fourth embodiment, as shown in FIGS. 24 through 26, the fifth embodiment is characterized in that a projecting section is provided at the end of the lower surface of the plug and that insertion holes  111 - 1  are formed at positions on an FFC  111  corresponding to the projecting section such that the projecting section act as a member for restricting the FFC  111 . In other respects, the fifth embodiment is identical with the fourth embodiment. 
     In order to place the FFC  111  on a plug  112 , one end of the FFC  111  is inserted into an insertion hole provided at the lower end of the plug  112 . The FFC  111  is inserted along a second lower surface  112 - 8 , a projecting section  112 - 4 , a recessed section  112 - 9 , and a first lower surface  112 - 7  of the plug  112 . The FFC  111  is turned along a half-round section  112 - 6  provided at the extremity of the plug  112  and inserted further along an upper surface  112 - 3  of the plug  112 . The holes  111 - 1  are engaged with engagement projections  112 - 2 . 
     The only requirement for fitting the plug  112 —which has the FFC  111  provided thereon and is shown in FIG.  25 —into a housing  113  is to insert a boss  112 - 1  of the plug  112  into an insertion hole  113 - 2  by way of an opening section  113 - 1  of the housing  113  while the FFC  111  is pulled gently in direction P (shown in FIG.  25 ). 
     In the fifth embodiment, the projecting section  112 - 4  and the recessed section  112 - 9  of the plug  112  come into contact with the recessed section  113 - 6  and the projecting section  113 - 5  of the housing  113  with the FFC  111  sandwiched therebetween, as in the case of the fourth embodiment. Even when great tensile force is exerted on the FFC  111 , application of intensive stress to the surroundings of the holes  111 - 1  of the FFC  111  is prevented, and hence no rip arises around the holes  111 - 1 . 
     In the fifth embodiment, a restriction member  112 - 12  restricts drooping of the FFC  111  from the lower surfaces  112 - 7 ,  112 - 8  of the plug  112 . Further, the direction in which the FFC  111  is to be pulled when the plug  112  is inserted into the opening section  113 - 1  of the housing  113  is not limited to the direction P and may be direction Q 1  or Q 2 , whereby a job of attaching the plug  112  to the housing  113  is improved further. 
     Sixth Embodiment 
     FIG. 27 is a cross-sectional view of a male connector housing according to a sixth embodiment of the present invention (after an FFC has been inserted into the housing; the view corresponds to a cross-sectional view taken along line A—A shown in FIG.  29 ). FIG. 28 is a plan view of the male connector housing according to the sixth embodiment. FIG. 29 is a side view of the connector housing shown in FIG. 27 when viewed from the right. FIG. 30 is a left-side elevation view of the connector housing shown in FIG. 27 when viewed from the left. 
     As shown in FIGS. 27 through 30, reference numeral  201  designates a male connector housing formed from resin through injection molding; and  202  designates an FFC. Reference numeral  201 - 1  designates a lock member. An engagement claw  201 - 2  is provided on the extremity of the lock member  201 - 1 . When the connector housing  201  is meshed with a female connector housing  203 , the engagement claw  201 - 2  is engaged with an engagement projection  203 - 1  provided on the female connector housing  203 . 
     Reference numeral  201 - 8  designates a guide used when the connector housing  201  is engaged with the female connector housing  203 . One guide  201 - 8  is provided on either side of the connector housing  201 , thus contributing to assurance of rigidity of the connector housing  201 . 
     Reference numeral  201 - 13  designates a storage section into which the FFC  202  is to be inserted. A retaining section  201 - 12  for retaining the FFC  202  is provided below the storage section  1 - 13 . An upper surface of the retaining section  201 - 12  acts as a retaining surface  201 - 15  for retaining the FFC  202 . Further, reference numeral  201 - 11  designates a ceiling surface of the storage section  201 - 13 . The ceiling surface  201 - 11  ends at substantially the center of the retaining surface  201 - 15 . 
     Reference numeral  201 - 3  designates a guide groove used when the FFC  202  is inserted into the connector housing  201 . The guide groove  1 - 3  is formed so as to extend from an insertion port  201 - 4  to root sections of the respective guides  201 - 8 ; that is, over substantially the entirety of the connector housing  201 . 
     Alternatively, one or a plurality of guides  201 - 8  may be additionally provided in the center of the connector housing  201 . Further, guide grooves analogous to the guide grooves  201 - 3  may be formed in the root sections of the guides  201 - 8 . 
     Reference numeral  201 - 6  designates protuberances for holding the FFC  202  which are provided on the retaining surface  201 - 15 . One surface of each protuberance  201 - 6  has a tapered surface  201 - 7 . 
     Reference numeral  201 - 5  designates grooves which are formed in the ceiling surface  201 - 11 , and each groove  201 - 5  has an U-shaped cross-sectional profile. The grooves  201 - 5  are situated at positions above the corresponding protuberances  201 - 6  provided on the retaining surface  201 - 15 . The grooves  201 - 5  are formed over the entirety of the ceiling surface  201 - 11  so as to extend from the insertion port  201 - 4  for the FFC  202  to an end  201 - 16  opposite the end at which the insertion port  201 - 4  is located. 
     Reference numeral  201 - 9  designates protection projections provided on respective sides of the lock member  201 - 1 . Engagement of the engagement claw  201 - 2  provided at the extremity of the lock member  201 - 1  with the engaging projection  203 - 1  of the male connector housing  203  carries out a protection function of preventing occurrence of inadvertent disengagement, which would otherwise arise when a connector is mounted on an automobile. 
     FIG. 31 is a plan view of an FFC according to the sixth embodiment. FIG. 32 is a descriptive view for describing the FFC according to the sixth embodiment when being inserted into the connector housing  201 . 
     FIG. 33 is a descriptive view showing the FFC according to the sixth embodiment after having been inserted into the connector housing  201 . 
     As shown in FIG. 31, reference numeral  202  designates an FFC; and  202 - 1  designates two holes provided side by side which are engaged with the protuberances  201 - 6  when the FFC  202  is inserted into the connector housing  201 , thereby effecting positioning of the FFC  202  and preventing removal of the FFC  202 . 
     Reference numeral  202 - 3  designates a conductor section constituting the circuitry of the FFC  202 . 
     Insertion of the FFC  202  into the connector housing  201  is performed through the following processes. Namely, as shown in FIG. 32, an extremity of the FFC  202  is inserted into the insertion port  201 - 4  of the connector housing  201  along the guide grooves  201 - 3 . 
     Upon arrival at the protuberances  201 - 6  of the connector housing  201 , the extremity  202 - 2  of the FFC  202  comes into contact with the tapered surfaces  201 - 7  and is deformed upward in a raised manner. When being inserted further, the extremity  202 - 2  is deformed downward along the guide grooves  201 - 3 , to come into collision with a longitudinal wall  201 - 10  of the connector housing  201 . In this position, the protuberances  201 - 6  are engaged with the engagement holes  202 - 1 , whereby insertion of the FFC  202  into the connector housing  201  is completed (FIG.  33 ). 
     In the present embodiment, the grooves  201 - 5 , each having an U-shaped cross-sectional profile and being situated at positions above the protuberances  201 - 6 , are formed over the entirety of the ceiling surface  201 - 11  so as to extend from the insertion port  201 - 4  for the FFC  202  to the end  201 - 16 . Hence, the FFC  202  can be smoothly inserted into the connector housing  201  with no constraint being imposed on deformation of the FFC  202 . 
     Since the FFC  202  is inserted while being guided by the guide grooves  201 - 3 , the FFC  202  does not levitate from the surface of the retaining surface  201 - 15  of the connector housing  201 . The extremity  202 - 2  is folded downward and housed in a shape restriction section  201 - 14 . Further, the extremity  202 - 2  remains in contact with the longitudinal wall  201 - 10 . Hence, when the connector housing  201  is inserted into the female connector housing  203 , no snag arises. 
     FIG. 34 is a cross-sectional view of the female connector housing  203  according to the sixth embodiment when viewed from the front (after a contact terminal has been inserted into the housing, and the drawing corresponds to a cross-sectional view taken along line B—B shown in FIG.  36 ). FIG. 35 is a plan view of the female connector housing  203  according to the sixth embodiment of the invention, and FIG. 36 is a side view of the female connector housing  203  shown in FIG. 34 when viewed from the left. 
     As shown in FIGS. 34 through 36, reference numeral  203  designates a female connector housing formed from resin through injection molding. 
     Provided on the outside of the female connector housing  203  are an engagement projection  203 - 1  to be engaged with the lock-member  201 - 1  of the connector housing  201 , and a protection member  203 - 2  for protecting the lock member  201 - 1 . Further, an accommodation chamber  203 - 3  is formed in the female connector housing  203  for receiving the connector housing  201 . 
     Four slits  203 - 5  into which contact terminals  204  are to be inserted are formed in the accommodation chamber  203 - 3 . Further, guide grooves  203 - 4  to be engaged with the guides  201 - 8  of the connector housing  201  are formed at respective longitudinal ends of the accommodation chamber  203 - 3 . 
     Locating pins  203 - 6  which effect positioning when the female connector housing  203  is mounted on a circuit board are provided at one end of the female connector housing  203 . 
     The contact terminals  204  are formed from a brass plate through pressmolding. Two rod-like sections  204 - 3  are provided at one end of each of the contact terminals  204 , and contacts  204 - 1  at formed at the extremities of the respective rod-like sections  204 - 3 . A solder tail  204 - 2  to be soldered to a through hole of a circuit board (not shown) is formed on the other end of each contact terminal  204 . 
     As shown in FIG. 34, attachment of the contact terminals  204  to the female connector housing  203  is completed by the following processes. Namely, as shown in FIG. 34, the contact terminals  204  are pushed into the slits  203 - 5  from the right end of the of the female connector housing  203 , to thereby cause projections  4 — 4  of the contact terminals  204  to mesh with the bottom surfaces of the respective slits  203 - 5 . An end face  203 - 7  of the female connector housing  203  is brought into contact with end faces  204 - 5  of the contact terminals  204 . 
     FIG. 37 is a cross-sectional view of the connector housing  201  and the female connector housing  203  according to the present embodiment when they are engaged with each other. 
     Engagement of the connector housing  201  having the FFC  202  inserted therein with the female connector housing  203  having the contact terminals  204  incorporated therein is performed through the following processes. As shown in FIG. 37, the connector housing  201  is inserted into the female connector housing  203  while the guides  201 - 8  are engaged with the guide grooves  203 - 4 . The extremity of the retaining section  201 - 12  of the connector housing  201  comes into collision with the contacts  204 - 1  of the contact terminals  204 , thereby resiliently deforming the rod-like sections  204 - 3  of the contact terminals  204 . The contacts  204 - 1  are electrically connected to the conductor sections  202 - 3  of the FFC  202 , thereby constituting a predetermined electrical circuit. The engagement claws  201 - 2  of the lock-member  201 - 1  of the connector housing  201  pass across and mesh with the engagement projections  203 - 1  of the female connector housing  203 . 
     At the time of engagement of the connector housing  201  with the female connector housing  203 , they can be smoothly engaged by means of the guides  201 - 8  of the connector housing  201  being engaged with the guide grooves  203 - 4  of the female connector housing  203 . 
     In contrast with the related-art male connector housing, the connector housing  201  is not divided into two parts; that is, the base member  255  and the fixing member  256 . Hence, the cost of parts is lowered, and ease of assembly is achieved. 
     According to the invention, an FFC is fastened in a male connector housing in a folded manner. Hence, even when the FFC is pulled strongly, a rip does not arise in the periphery of lock projections. 
     The FFC is inserted into the male connector housing by way of an opening section thereof along a slit, thus realizing ease of attachment. 
     As long as the male connector housing is formed integrally with a retainer, the cost of parts is lowered, thereby facilitating attachment of the retainer to a much greater extent. 
     According to the invention, since the male connector housing is provided with guide ribs which act as guides when a female connector housing is engaged with the male connector housing, ease of engagement is achieved. 
     According to the invention, the FFC is fastened in the male connector housing in a folded manner. Hence, even when the FFC is pulled strongly, a rip does not arise in the periphery of the engagement projections. 
     Even when being pulled, the FFC is strongly sandwiched between a male connector housing and a retaining member and becomes stable. 
     The only requirement for achieving secure engagement is to insert the FFC into the connector housing along the slits formed in the retaining member, thereby realizing superior workability. 
     According to the invention, the male connector housing, an insertion port, and the slits of a temporarily-held retaining member are level with each other. Hence, ease of attachment of the FFC is improved further. There is yielded an advantage of an improvement in an operation for inserting a retaining member into a male connector housing. 
     According to the invention, the FFC is folded through 180°, and an electrical connection section is formed on either of upper and lower surfaces of the thus-folded FFC. Hence, the density of an electrical circuit can be increased, thereby yielding an advantage of rendering the cost of parts lower So long as the connector for use in connecting an FFC according to the present invention is attached to a plurality of positions on the FFC  22  in a longitudinal direction thereof, identical male connectors  21  are connected in shunt with each other on the FFC. As a result, there is yielded an advantage of the ability to constitute, from a smaller number of components, a wire harness suitable for use in connecting circuit units which are to be coupled together through multiplex communication. 
     According to the invention, the FFC is fastened to the inside of the male connector housing in a folded manner. Hence, even when the FFC is pulled strongly, a rip will not arise in the periphery of engagement projections. 
     According to the invention, a projecting section and a recessed section of a plug come into contact with a recessed section and a projecting section of a housing with an FFC sandwiched therebetween, thus holding the FFC. Hence, even when great tensile force is exerted on the FFC, application of intensive stress to the surroundings of the holes of the FFC is prevented, thereby preventing occurrence of a rip around the holes. 
     According to the invention, a restriction member  112 - 12  restricts drooping of the FFC  111  from the lower surfaces  112 - 7 ,  112 - 8 . As a result, there is yielded an advantage of affording a greater degree of freedom of a direction in which tensile force is to be exerted on an FFC when a plug is inserted into an opening section of a housing, as well as an advantage of an improvement in ease of attachment of a plug to a housing. 
     According to the invention, a male connector housing is integrally formed from resin. Hence, there is yielded an advantage of the cost of parts being lowered. 
     Protuberances to be engaged with engagement holes formed in an FFC are provided on a retaining surface for retaining an FFC of a male connector housing. Warpage spaces for an FFC are provided on a ceiling surface situated at a position above the protuberances. Each of the spaces has an U-shaped cross-sectional profile, and the spaces are formed so as to extend from an insertion port for an FFC to an end opposite an end at which the insertion port is provided. Hence, when an FFC is inserted into the male connector housing, the FFC is deformed upward in a raised manner upon arrival at the protuberances. There is yielded an advantage of the ability to smoothly insert an FFC into a male connector housing without constraints being imposed on deformation of the FFC. 
     Since the FFC is inserted while being guided by the guide grooves, the FFC does not levitate from the retaining surface of the male connector housing. Namely, the extremity of the FFC is folded downward and housed in a shape restriction section of the male connector housing and remains in contact with a longitudinal wall. Hence, there is yielded an advantage of no snag arising when the male connector housing is engaged with the female connector housing.