Patent Publication Number: US-11652318-B2

Title: Electrical connector with a flat-type conductor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2020-175547, filed Oct. 19, 2020, the contents of which are incorporated herein by reference in its entirety for all purposes. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an electrical connector with a flat-type conductor. 
     Background Art 
     A connector for matingly connecting a front end section of a flat-type conductor with a strip-like configuration extending in a forward-backward direction to a counterpart connector has been disclosed in Patent Document 1. The connector of Patent Document 1, which has a flat-type conductor (flat circuit) and a housing (slider) that holds and retains in place a front end section of said flat-type conductor, is matingly connected to a circuit board-mounted counterpart connector (board connector) from the rear. 
     The flat-type conductor has formed therein a plurality of circuits extending in the forward-backward direction that are arranged in the strip width direction of said flat-type conductor. Notch-shaped slider engagement apertures, which are intended for engagement with the housing, are formed on the opposite side edges of the front end section of said flat-type conductor, in other words, on each side of the circuit array range in the strip width direction. A slit-shaped circuit insertion aperture is formed in the housing along the top face of the bottom wall of said housing, and the front end section of said flat-type conductor is adapted to be inserted into said circuit insertion aperture from the rear. A locking portion (locking arm) intended for locking to a counterpart connector is provided at the center of the housing in the strip width direction and, in addition, at both ends of the housing in the strip width direction, in other words, at locations different from the locking portion, flexible engagement pieces engageable with the front end edges of said slider engagement apertures are provided at locations corresponding to the slider engagement apertures of the flat-type conductor. Said flexible engagement pieces have resilient pieces, which extend in the forward-backward direction and are resiliently deformable in the thickness direction of the flat-type conductor (up-down direction), and engagement projections, which protrude downwardly from said resilient pieces. 
     When the front end section of the flat-type conductor is attached to the housing, said front end section is inserted into the circuit insertion aperture of the housing from the rear and, upon abutting the engagement projections from the rear, is inserted further forward while resiliently deforming the resilient pieces upward. When the slider engagement apertures reach the location of the engagement projections, the resilient pieces return to the free state and the engagement projections enter the slider engagement apertures from above. As a result, the engagement projections are positioned so as to engage the front end edges of the slider engagement apertures from the rear, thereby preventing inadvertent decoupling of the flat-type conductor from the housing. 
     PATENT DOCUMENTS 
     [Patent Document 1] 
     
         
         Japanese Patent No. 5,909,410. 
       
    
     SUMMARY 
     Problems to be Solved 
     Generally speaking, a requirement that is often imposed upon electrical connectors with a flat-type conductor is profile reduction in the strip width direction of the flat-type conductor. However, according to Patent Document 1, preventing the decoupling of the flat-type conductor required forming slider engagement apertures at the opposite side edges of the flat-type conductor and also required providing flexible engagement pieces at the opposite ends of the housing, which made it difficult to reduce the dimensions of the electrical connector with a flat-type conductor in the strip width direction. In addition, the flexible engagement pieces were positioned differently from the locking portion, which also precluded reducing the dimensions of the electrical connector with a flat-type conductor in the strip width direction. 
     In view of the aforesaid circumstances, it is an object of the present invention to provide an electrical connector with a flat-type conductor that makes it possible to avoid an increase in the size of the flat-type conductor in the strip width direction while preventing inadvertent decoupling of the flat-type conductor from the housing. 
     Technical Solution 
     The inventive electrical connector with a flat-type conductor is an electrical connector with a flat-type conductor intended for matingly connecting a front end section of a flat-type conductor with a strip-like configuration extending in the forward-backward direction to a counterpart electrical connector, and comprises said flat-type conductor, which has formed therein a plurality of circuits extending in the forward-backward direction that are arranged in the strip width direction of the flat-type conductor, a housing holding the front end section of the flat-type conductor, and a retainer attached to the housing for supporting the front end section of the flat-type conductor. 
     According to the present invention, in such an electrical connector with a flat-type conductor, the housing has a locking portion, which is positioned within the range between the circuits positioned at the outermost ends in the strip width direction of the flat-type conductor and is lockable to the counterpart electrical connector, and a holding space which holds the retainer along with the front end section of the flat-type conductor, the front end section of the flat-type conductor has formed therein a pass-through portion extending through the flat-type conductor in the thickness direction of said flat-type conductor at a location at least partially overlapping with the locking portion in the strip width direction, and the retainer has a protrusion that protrudes in the thickness direction of the flat-type conductor and enters the pass-through portion of the flat-type conductor, thereby making is possible to limit the rearward movement of the flat-type conductor with the help of said protrusion. 
     In the present invention, the protrusion of the retainer is introduced into the pass-through portion of the flat-type conductor and said protrusion is enabled for engagement with the front end edge of said pass-through portion, thereby limiting the rearward movement of the flat-type conductor and preventing inadvertent decoupling of the flat-type conductor from the housing. As disclosed herein, the pass-through portion of the flat-type conductor and the protrusion of the retainer are positioned within the range between the circuits positioned at the outermost ends in the strip width direction of the flat-type conductor. Therefore, an increase in the size of the electrical connector with a flat-type conductor in the strip width direction can be avoided because in the present invention it is no longer necessary, as in the prior art, to provide a mechanism for preventing the decoupling of the flat-type conductor at more outer locations than the circuits positioned at the opposite ends in the strip width direction, in other words, at the outermost ends in the strip width direction. 
     In the present invention, the protrusion of the retainer may be positioned so as to be inserted into the pass-through portion of the flat-type conductor such that a protruding apex portion protrudes from the pass-through portion, and, in the walls that form the holding space, the housing may have a recessed portion that permits entry of the protruding apex portion of the protrusion, thereby making it possible to limit the movement of the protrusion in the strip width direction of the flat-type conductor along the inner surface of said recessed portion. 
     In this manner, being able to limit the movement of the protrusion of the retainer in the strip width direction of the flat-type conductor along the inner surface of the recessed portion of the housing makes it possible not only to prevent rearward decoupling of the retainer and, by extension, the flat-type conductor, but also to fix its position in the strip width direction. 
     In the present invention, the recessed portion of the housing may be formed in the shape of a rearwardly open groove extending in the forward-backward direction and may be adapted to permit entry of the protruding apex portion of the retainer from the rear. 
     In this manner, forming the recessed portion in the shape of a rearwardly open groove makes it possible to attach the retainer to the housing from the rear. 
     Technical Effect 
     In the present invention, as described above, the pass-through portion of the flat-type conductor and the protrusion of the retainer intended for preventing the decoupling of the flat-type conductor are positioned within the range between the circuits positioned at the outermost ends in the strip width direction of the flat-type conductor. Therefore, it is no longer necessary, as in the prior art, to provide a mechanism for preventing the decoupling of the flat-type conductor at more outer locations than the circuits positioned at the opposite ends in the strip width direction, in other words, at the outermost ends in the strip width direction. As a result, an increase in the size of the electrical connector with a flat-type conductor in the strip width direction can be avoided while preventing inadvertent decoupling of the flat-type conductor from the housing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    illustrates a posterior perspective view of an electrical connector assembly according to an embodiment of the present invention, shown prior to connector mating. 
         FIG.  2    illustrates a posterior perspective view of the electrical connector assembly of  FIG.  1   , shown after connector mating. 
         FIG.  3    illustrates an exploded perspective view of the components of the electrical connector with a flat-type conductor used in the electrical connector assembly of  FIG.  1   . 
         FIG.  4    (A) is a plan view of the flat-type conductor, and  FIG.  4    (B) is a bottom view of the flat-type conductor. 
         FIGS.  5    (A) and  5  (B) are views illustrating the electrical connector with a flat-type conductor used in the electrical connector assembly of  FIG.  1    in isolation, where  FIG.  5    (A) is an anterior perspective view, and  FIG.  5    (B) is an anterior front view. 
         FIGS.  6    (A) and  6  (B) are views illustrating the retainer of the electrical connector with a flat-type conductor of  FIG.  5    in isolation, where  FIG.  6    (A) is an anterior perspective view, and  FIG.  6    (B) is an anterior front view. 
         FIGS.  7    (A) and  7  (B) are perspective views illustrating the flat-type conductor with the retainer attached, where  FIG.  7    (A) is a view from above, and  FIG.  7    (B) is a view from below. 
         FIG.  8    illustrates a cross-sectional view of the electrical connector with a flat-type conductor of  FIG.  1    that is perpendicular to the up-down direction and shows a cross-section taken across the lateral arm portions of the housing and the lateral engageable portions of the retainer. 
         FIGS.  9    (A) and  9  (B) are posterior rear views of the electrical connector with a flat-type conductor of  FIG.  1   , and  FIG.  9    (B) is a partial enlarged view of  FIG.  9    (A). 
         FIG.  10    illustrates a posterior perspective view of the counterpart electrical connector used in the electrical connector assembly of  FIG.  1   . 
         FIG.  11    (A) is a posterior perspective view of a counterpart terminal, and  FIG.  11    (B) is a posterior perspective view of an anchor fitting. 
         FIGS.  12    (A) to  12  (C) illustrate cross-sectional views of the electrical connector assembly of  FIG.  2    taken in a plane perpendicular to the connector width direction, where  FIG.  12    (A) is a cross-sectional view taken across the counterpart terminals,  FIG.  12    (B) is a cross-sectional view taken across the locking portion of the housing and the protrusion of the retainer, and  FIG.  12    (C) is a partial enlarged view of  FIG.  12    (B). 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention are described below with reference to the accompanying drawings. 
       FIG.  1    and  FIG.  2    are perspective views of the electrical connector assembly according to the present embodiment, shown prior to connector mating in  FIG.  1    and after connector mating in  FIG.  2   .  FIG.  3    is an exploded perspective view of the components of the electrical connector with a flat-type conductor used in the electrical connector assembly of  FIG.  1   . In the present embodiment, the electrical connector assembly comprises an electrical connector with a flat-type conductor  1  (referred to as “connector  1 ” below) and a counterpart electrical connector (referred to as “counterpart connector  2 ” below), which are removably connected such that the forward-backward direction (X-direction) is the direction of connector insertion and removal. The connector  1  is mated with the counterpart connector  2  mounted to a mounting face of a circuit board (not shown) in the forward direction (X 1  direction), and is thus matingly connected to the counterpart connector  2 . 
     The connector  1  comprises a flat-type conductor C extending in the forward-backward direction, a housing  10  holding a front end section of the flat-type conductor C, and a retainer  20  attached to the housing  10  such that it can support the front end section of the flat-type conductor C from the rear. The housing  10  and the retainer  20  are made of resin or another electrically insulating material. 
       FIG.  4    (A) is a plan view of the flat-type conductor C, and  FIG.  4    (B) is a bottom view of the flat-type conductor C. The flat-type conductor C has a strip-like configuration extending in the forward-backward direction (X-direction) such that the connector width direction (Y-direction) is the strip width direction. The flat-type conductor C has a plurality of circuits C 1  extending in the forward-backward direction arranged thereon in the strip width direction of the flat-type conductor C (Y-direction). As can be seen in  FIG.  4    (A), a circuit-free range S, in which no circuits are present, is formed in the central area of the flat-type conductor C in the strip width direction. That is to say, the plurality of circuits C 1  are separated by the circuit-free range S in the strip width direction and divided into two circuit groups. The circuits C 1  extend all the way to the front end of the flat-type conductor C (end on side X 1 ). As can be seen in  FIG.  4    (A), the circuits C 1  have their front end sections exposed on the top face of the flat-type conductor C, and these exposed sections serve as contact portions C 1 A intended for contacting the hereinafter-described counterpart terminals  30  of the counterpart connector  2 . As can be seen in  FIG.  4    (B), a reinforcing plate C 2  is adhered to the bottom face of a front end section of the flat-type conductor C in order to reinforce the front end section. 
     In addition, in the flat-type conductor C has formed therein a pass-through portion C 3  disposed in the thickness direction of the flat-type conductor C, i.e., in the up-down direction (Z-axis direction) at a location rearward of the contact portions C 1 A within the circuit-free range S in the strip width direction. The pass-through portion C 3  forms an aperture of a quadrangular shape and is disposed through both the main body of the flat-type conductor C and the reinforcing plate C 2  (see  FIG.  12    (C)). As described below, the pass-through portion C 3  allows for the hereinafter-described protrusion  21 C of the retainer  20  to be inserted therein from above, in other words, from the top side of the flat-type conductor C (see  FIG.  7    (B),  FIG.  12    (C)). 
     As can be seen in  FIG.  4    (A) and  FIG.  4    (B), in the present embodiment, the pass-through portion C 3  is formed at a location slightly offset from the center of the flat-type conductor C in the strip width direction (Y-direction) toward side Y 2 . Positioning the pass-through portion C 3  with an offset from the center in the strip width direction makes it possible to prevent the retainer  20  from being attached from the underside of the flat-type conductor C by mistake. In addition, in the present embodiment, the pass-through portion C 3  is positioned within a range overlapping with the hereinafter-described locking portion  11 E of the housing  10  in the connector width direction. 
     As can be seen in  FIG.  3   , the housing  10  has a substantially rectangular parallelepiped-like exterior configuration whose longitudinal direction is the connector width direction (Y-direction), and, along with having a mating portion  10 A mating with the hereinafter-described counterpart housing  40  in substantially the front half (section on side X 1 ) thereof, has a retainer installation portion  10 B used for installing the retainer  20  from the rear in substantially the rear half (section on side X 2 ) thereof. In addition, two partition walls  10 C extending in the connector width direction (see  FIG.  8   ) are provided within the interior space of the housing  10  at an intermediate location of the mating portion  10 A in the forward-backward direction (X-direction), such that the interior space is divided by the partition walls  10 C in the forward-backward direction. Specifically, the interior space is divided into two front receiving spaces  10 D formed forwardly of the partition walls  10 C and one rear receiving space  10 E formed rearwardly of the partition walls  10 C. The front receiving spaces  10 D are spaces intended for receiving the hereinafter-described nested portions  44  of the counterpart connector  2  from the front when the connectors are put in a mated state. These front receiving spaces  10 D are positioned in alignment with each of the two previously described circuit groups of the flat-type conductor C in the connector width direction. The rear receiving space  10 E is a holding space intended for receiving the retainer  20  from the rear and holding it therein. 
     In addition, a space extending and expanding in the forward-backward direction across the inner surface (top face) of the bottom walls (the hereinafter-described front bottom wall  12  and rear bottom wall  17 ) of the housing  10  is formed to serve as a flat-type conductor insertion space  10 F within the interior space of the housing  10  (see  FIGS.  12    (A) and  12  (B)). The flat-type conductor insertion space  10 F holds the front end section of the flat-type conductor C inserted from the rear (see  FIGS.  12    (A) and  12  (B)). When the front end section of the flat-type conductor C is held within the flat-type conductor insertion space  10 F, the top face of the bottom wall of the housing  10  is brought into surface contact or close proximity with the bottom face of the flat-type conductor C and can support the bottom face of the flat-type conductor C. 
     As can be seen in  FIGS.  5    (A) and  5  (B), a locking portion holding space  10 G intended for holding the hereinafter-described locking portion  11 E is formed in the top walls of the housing  10  (the hereinafter-described front top wall  11  and rear top wall  16 ) in the central area in the connector width direction (within a range corresponding to the circuit-free range of the flat-type conductor C) and throughout the entire extent in the forward-backward direction. Within the bounds of the hereinafter-described front top wall  11  in the forward-backward direction, the locking portion holding space  10 G includes a front holding space  10 G- 1  which, along with being recessed roughly to the center of the housing  10  in the up-down direction, extends throughout the entire extent of the front top wall  11  in the forward-backward direction, and, within the bounds of the hereinafter-described rear top wall  16  in the forward-backward direction, a rear holding space  10 G- 2  which, along with passing through the rear top wall  16  in the up-down direction, extends throughout the entire extent of the rear top wall  16  in the forward-backward direction. As can be seen in  FIGS.  5    (A) and  5  (B), the bottom interior wall surface of the front holding space  10 G- 1 , in other words, the top face of the front top wall  11 , is in roughly the same position as the center of the receiving spaces  10 D in the up-down direction. 
     The mating portion  10 A comprises: a front top wall  11  and a front bottom wall  12 , which serve as mating walls extending in the connector width direction and opposed in the up-down direction; a pair of front lateral walls  13 , which extend in the up-down direction at the opposite ends in the connector width direction and couple the front top wall  11  to the front bottom wall  12 ; and a plurality of partition walls  14 , which extend in the up-down direction and couple the front top wall  11  to the front bottom wall  12 . 
     Protruding walls  11 A- 11 D, which protrude from the top face of the front top wall  11  while extending in the forward-backward direction, are formed on the front top wall  11  at two locations in the intermediate area and at the opposite side edges in the connector width direction. Specifically, as can be seen in  FIG.  3    and  FIG.  5   , the protruding walls  11 A- 11 D include a first protruding wall  11 A, a second protruding wall  11 B, a third protruding wall  11 C, and a fourth protruding wall  11 D successively in a spaced relationship from side Y 1  to side Y 2 . The first protruding wall  11 A and fourth protruding wall  11 D are positioned at the opposite side edges of the front top wall  11  in the connector width direction, and the second protruding wall  11 B and third protruding wall  11 C are positioned in the intermediate area of the front top wall  11  in the connector width direction. In the present embodiment, the protruding walls  11 A- 11 D are formed such that the order of their decreasing width is: the third protruding wall  11 C, second protruding wall  11 B, first protruding wall  11 A, and fourth protruding wall  11 D. The previously discussed front holding space  10 G- 1  is formed between the second protruding wall  11 B and third protruding wall  11 C. 
     In addition, a cantilevered locking portion  11 E extending rearwardly from the front end of the top face of the front top wall  11  to the rear end of the housing  10  is formed at the center of the front top wall  11  in the connector width direction. The locking portion  11 E has a locking arm portion  11 E- 1  which extends in the forward-backward direction at a location spaced from the top face of the front top wall  11  and is resiliently deformable in the up-down direction, and a locking protrusion  11 E- 2  which serves as a locking engagement portion protruding upwardly at an intermediate location of the locking arm portion  11 E- 1  in the forward-backward direction. The locking portion  11 E can be locked by engaging the hereinafter-described locking aperture  41 F of the counterpart connector  2  with the locking protrusion  11 E- 2 . In addition, the rear end portion (free end portion) of the locking arm portion  11 E- 1  serves as an operative portion  11 E- 1 A, to which a pressing operation (unlocking operation) is applied from above for unlocking from the counterpart connector  2 . 
     In the present embodiment, the locking arm portion  11 E- 1 , with the exception of the operative portion  11 E- 1 A, is held within the front holding space  10 G- 1  of the locking portion holding space  10 G, and the operative portion  11 E- 1 A is held within the rear holding space  10 G- 2  of the locking portion holding space  10 G. In other words, the locking portion  11 E is positioned within a range overlapping with the front receiving spaces  10 D and rear receiving space  10 E of the housing  10  (collectively referred to as “receiving spaces  10 D,  10 E” below whenever necessary) in the forward-backward direction. In addition, the locking protrusion  11 E- 2  is positioned so as to protrude above the front holding space  10 G- 1 . 
     The locking portion  11 E, along with being positioned differently from the position of the receiving spaces  10 D,  10 E when viewed in the up-down direction, is positioned such that the bottom portion of the locking arm portion  11 E- 1  overlaps with the receiving spaces  10 D,  10 E in the up-down direction (see  FIGS.  5    (A) and  5  (B)). Therefore, in comparison with providing the locking portion above the receiving spaces of the housing, as in the prior art, in the present embodiment, greater profile reduction can be achieved by making the housing  10  and, by extension, the connector  1 , smaller in the up-down direction in exact proportion to the overlap of the locking portion with the receiving spaces  10 D,  10 E. 
     As can be seen in  FIGS.  5    (A) and  5  (B), a top ridge portion  11 F is formed on the top face of the front top wall  11  at a location proximate the second protruding wall  11 B outwardly of the second protruding wall  11 B in the connector width direction, and, in addition, at a location proximate the third protruding wall  11 C outwardly of the third protruding wall  11 C in the connector width direction. The top ridge portions  11 F protrude from the top face of the front top wall  11  at the rear end of the front top wall  11  while extending in the forward-backward direction. The top ridge portions  11 F are brought into biting engagement with the inner surface (bottom face) of the counterpart top wall  41  of the counterpart connector  2  when the connectors are in a mated state. 
     Bottom ridge portions  12 A of the same shape as the top ridge portions  11 F are formed on the bottom face of the front bottom wall  12  in the same positions as the top ridge portions  11 F on the front top wall  11  when viewed in the up-down direction (see  FIG.  5    (B)). 
     As can be seen in  FIGS.  5    (A) and  5  (B), the partition walls  14  are formed to be arranged at equal intervals in the connector width direction within the bounds of the two front receiving spaces  10 D, in other words, the front receiving spaces  10 D positioned on the opposite sides of the front holding space  10 G- 1  in the connector width direction (see also  FIG.  8   ). The respective front receiving spaces  10 D are split by these partition walls  14  in the connector width direction. 
     As can be seen in  FIG.  3   , the retainer installation portion  10 B has a rear top wall  16  and a rear bottom wall  17  which extend in the connector width direction and are opposed in the up-down direction, and a pair of rear lateral walls  18  which extend in the up-down direction at the opposite ends in the connector width direction and couple the rear top wall  16  to the rear bottom wall  17 . The retainer installation portion  10 B is made larger than the mating portion  10 A in the connector width direction, and the rear lateral walls  18  are positioned outwardly of the front lateral walls  13  in the connector width direction. 
     Limiting walls  16 A, which protrude from the top face of the rear top wall  16 , are formed on the rear top wall  16  on the opposite sides of the operative portion  11 E- 1 A of the locking portion  11 E at locations proximate the center in the connector width direction. The limiting walls  16 A are positioned in a manner to permit abutment against the operative portion  11 E- 1 A in the connector width direction in order to limit excessive resilient deformation of the locking portion  11 E in the connector width direction. Rear top groove portions  16 B, which are recessed from the bottom face of the rear top wall  16  while extending in the forward-backward direction, are formed in the rear top wall  16  at locations proximate the lateral edges in the connector width direction. The rear top groove portions  16 B are open toward the rear and permit posterior entry of the top portions of the hereinafter-described support wall portions  22  of the retainer  20 . 
     A groove-shaped limiting recessed portion  17 A, which is positioned within the circuit-free range S in the connector width direction and extends in the forward-backward direction, is formed in the rear bottom wall  17 . The limiting recessed portion  17 A, which is positioned in alignment with the hereinafter-described protrusion  21 C of the retainer  20  in the connector width direction and is open toward the rear, permits posterior entry of the protruding apex portion  21 C- 1  of the protrusion  21 C of the retainer  20  (see  FIG.  9    (B)). Among the inner surfaces of the limiting recessed portion  17 A, the surfaces located on the opposite sides in the connector width direction (surfaces perpendicular to the connector width direction) serve as limiting faces  17 A- 1  capable of limiting the movement of the protruding apex portion  21 C- 1  and, by extension, the retainer  20 , in the connector width direction. In addition, rear bottom groove portions  17 B are formed in the rear bottom wall  17  in the same positions as the rear top groove portions  16 B when viewed in the up-down direction. The rear bottom groove portions  17 B, which are recessed from the top face of the rear bottom wall  17  and extend in the forward-backward direction while being open toward the rear, permit posterior entry of the bottom portions of the hereinafter-described support wall portions  22  of the retainer  20 . 
     As can be seen in  FIG.  8   , lateral arm portions  18 A, which extend from the inner surface of the rear end portions of the rear lateral walls  18  forwardly along said inner surface, are formed on the rear lateral walls  18 . The lateral arm portions  18 A have a cantilever configuration, in which the front end portions are free end portions and are resiliently deformable in the connector width direction. Lateral engagement protrusions  18 A- 1 , which protrude inwardly in the connector width direction, are formed in the front end portions of the lateral arm portions  18 A. The lateral engagement protrusions  18 A- 1  can engage the hereinafter-described lateral engageable portions  22 A of the retainer  20  from the rear with their front end faces (flat faces perpendicular to the forward-backward direction) and prevent inadvertent decoupling of the retainer  20 . 
     As can be seen in  FIG.  3   , in the present embodiment, anti-drip walls  10 H, which protrude from the top face of the housing  10  outwardly of the limiting walls  16 A in the connector width direction, are formed at the boundary between the mating portion  10 A and the retainer installation portion  10 B in the forward-backward direction. As can be seen in  FIG.  2   , these anti-drip walls  10 H are positioned to seal gaps formed between the front top wall  11  of the connector  1  and the counterpart top wall  41  of the counterpart connector  2  when the connectors are in a mated state. Sealing the gaps in this manner with the anti-drip walls  10 H prevents water droplets generated as a result of dew condensation outside the connector from penetrating the interior of the counterpart connector  2 . 
     As can be seen in  FIGS.  1  to  3   , in the present embodiment, rearwardly open rear recessed portions  101  are formed rearwardly of the anti-drip walls  10 H. Consequently, when the housing  10  is fabricated, the anti-drip walls  10 H can be formed simply by disposing a mold (not shown) from the rear, molding the housing  10 , and then pulling said mold backward. In other words, there is no need to use a plurality of molds to form the anti-drip walls  10 H, and a mold of a simple shape can be used. 
     As can be seen in  FIG.  3   , the retainer  20  has a central plate portion  21  which extends such that the connector width direction is its longitudinal direction while having roughly the same dimensions as the strip width dimensions of the flat-type conductor C, and support wall portions  22  which are formed at the opposite ends of the central plate portion  21  in the connector width direction. 
     As can be seen in  FIG.  3   , the front end portion of the central plate portion  21  has a cutout made in the central area in the connector width direction, specifically, at a location corresponding to the circuit-free range S of the flat-type conductor, thereby forming a notched portion  21 A (see  FIG.  6    (A)). The fact that the notched portion  21 A is forwardly open makes it possible to avoid interference between the retainer  20  and the housing  10  when the retainer  20  is attached to the housing  10  (see  FIG.  8   ). A forwardly open top recessed portion  21 B recessed from the top face of the central plate portion  21  is formed in the central area of the central plate portion  21  in the connector width direction at a location rearward of the notched portion  21 A. The top recessed portion  21 B is made smaller in size in the connector width direction than the notched portion  21 A. When the retainer  20  is attached to the housing  10 , the top recessed portion  21 B is positioned under the operative portion  11 E- 1 A of the locking portion  11 E of the housing  10  (see  FIG.  12    (B)), thereby allowing the operative portion  11 E- 1 A and, by extension, the locking portion  11 E, to be downwardly resiliently deformable to a sufficient extent. 
     In addition, at a location within the circuit-free range S in the connector width direction and rearward of the notched portion  21 A, the central plate portion  21  has a protrusion  21 C of a generally rectangular prismatic shape that protrudes downwardly from the bottom face of the central plate portion  21 . The protrusion  21 C is positioned with a slight offset from the center toward side Y 1 , in alignment with the limiting recessed portion  17 A of the housing  10  and the pass-through portion C 3  of the flat-type conductor C in the connector width direction (see also  FIG.  6    (B)). In cross-section perpendicular to the up-down direction, the protrusion  21 C has a quadrangular shape that is slightly smaller than the pass-through portion C 3  of the flat-type conductor C, which allows for it to be inserted into the pass-through portion C 3  from above. The dimensions of the protrusion  21 C in the up-down direction are larger than the thickness dimensions of the flat-type conductor C and, as can be seen in  FIG.  7    (B), the protruding apex portion  21 C- 1  of the protrusion  21 C inserted into the pass-through portion C 3  protrudes downwardly past the pass-through portion C 3  (see also  FIGS.  9    (A) and  9  (B) and  FIGS.  12    (B) and  12  (C)). In addition, the protrusion  21 C is slightly smaller than the limiting recessed portion  17 A of the housing  10  in the connector width direction and thus permits rear entry of the protruding apex portion  21 C- 1  of the protrusion  21 C into the limiting recessed portion  17 A when the retainer  20  is attached to the housing  10  (see  FIGS.  9    (A) and  9  (B)). 
     The connector  1  is assembled in accordance with the following procedure. First, the protrusion  21 C of the retainer  20  is inserted into the pass-through portion C 3  in the front end section of the flat-type conductor C from above, thereby causing the protruding apex portion  21 C- 1  of the protrusion  21 C to protrude downwardly through the pass-through portion C 3 . Next, with the protrusion  21 C remaining inserted into the pass-through portion C 3  (in the state illustrated in  FIGS.  7    (A) and  7  (B)), the front end section of the flat-type conductor C and the retainer  20  are attached to the housing  10  from the rear. As a result, the front end section of the flat-type conductor C is inserted into the flat-type conductor insertion space  10 F of the housing  10  from the rear, and the contact portions C 1 A of the flat-type conductor C reach the front receiving spaces  10 D of the housing  10  (see  FIG.  8    and  FIG.  12    (A)). 
     In addition, in the process of attaching the retainer  20 , the front ends of the lateral engageable portions  22 A of the retainer  20  abut the lateral engagement protrusions  18 A- 1  of the lateral arm portions  18 A and cause the lateral arm portions  18 A to be resiliently deformed outwardly in the connector width direction, thereby permitting further insertion of the retainer  20 . Once the lateral engageable portions  22 A have passed the location of the lateral engagement protrusions  18 A- 1 , the lateral arm portions  18 A return to the free state, and the lateral engagement protrusions  18 A- 1  are positioned in a manner to permit engagement with the lateral engageable portions  22 A from the rear (see  FIG.  8   ), thereby preventing inadvertent decoupling of the retainer  20 . In addition, the protruding apex portion  21 C- 1  of the protrusion  21 C of the retainer  20  enters the limiting recessed portion  17 A of the housing  10  from the rear (see  FIG.  9    (B) and  FIG.  12    (C)). 
     When the retainer  20  is attached to the housing  10 , the protrusion  21 C of the retainer  20  engages the front end edge C 3 A of the pass-through portion C 3  of the flat-type conductor C (see  FIG.  3   ,  FIG.  7    (B), and  FIG.  12    (C)) from the rear, which limits the rearward movement of the flat-type conductor C and prevents inadvertent decoupling of the flat-type conductor C. In addition, the protruding apex portion  21 C- 1  of the protrusion  21 C is held within the limiting recessed portion  17 A of the housing  10  and the movement of the protruding apex portion  21 C- 1  in the connector width direction is limited by the limiting faces  17 A- 1  of the limiting recessed portion  17 A, thereby positioning the retainer  20  and the flat-type conductor C in the connector width direction. Attaching the retainer  20  to the housing  10  in this manner completes the assembly of the connector  1 . 
     In the present embodiment, the rearward movement of the flat-type conductor C is limited and inadvertent decoupling of the flat-type conductor C from the housing  10  is prevented by introducing the protrusion  21 C of the retainer  20  into the pass-through portion C 3  of the flat-type conductor C and enabling engagement of the protrusion  21 C with the front end edge C 3 A of the pass-through portion C 3 . Here, the pass-through portion C 3  of the flat-type conductor C and the protrusion  21 C of the retainer  20  are positioned within the circuit-free range S, in other words, within the range between the circuits C 1  positioned at the outermost ends in the strip width direction of the flat-type conductor C (connector width direction). Employing the circuit-free range S of the flat-type conductor C in this manner eliminates the need to provide a mechanism for preventing the decoupling of the flat-type conductor C at more outer locations than the circuits C 1  positioned at the opposite ends in the strip width direction, i.e., at the outermost ends in the strip width direction, as in the prior art, thereby making it possible to avoid an increase in the size of the connector  1  in the strip width direction while preventing inadvertent decoupling of the flat-type conductor C from the housing  10 . 
     In addition, according to the present embodiment, the pass-through portion C 3  of the flat-type conductor C is positioned within a range overlapping with the locking portion  11 E of the housing  10  in the strip width direction within the circuit-free range S, which also helps avoid an increase in the size of the connector  1  in the strip width direction as compared to providing the pass-through portion C 3  and the locking portion  11 E at different locations in the connector width direction. 
     As can be seen in  FIG.  10   , the counterpart connector  2  has a plurality of counterpart terminals  30  arranged in alignment with the plurality of contact portions C 1 A of the flat-type conductor C of the connector  1  in the connector width direction (Y-axis direction), a counterpart housing  40  having a plurality of counterpart terminals  30  press-fitted and retained in place therein, and anchor fittings  50  press-fitted and retained in place within the counterpart housing  40  outside of the array range of the counterpart terminals  30  in the connector width direction. 
     As can be seen in  FIG.  11    (A), the counterpart terminals  30  are blanked out of a sheet metal member in the through-thickness direction and have a planar configuration with major faces maintaining their flatness. The counterpart terminals  30  are arranged in an orientation in which their through-thickness direction coincides with the connector width direction (Y-axis direction), and such that the direction of the terminal array is the connector width direction. In the present embodiment, the counterpart terminals  30  consist of two groups of counterpart terminals positioned in alignment with the two front receiving spaces  10 D of the connector  1  in the connector width direction. 
     As can be seen in  FIG.  11    (A), the counterpart terminals  30  each have a base portion  31  with a substantially quadrangular planar configuration, a long arm portion  32  and a short arm portion  33  extending rearwardly from the rear end edge (the end edge extending in the up-down direction on side X 2 ) of the base portion  31 , a leg portion  34  extending downwardly from the bottom edge of the front end portion of the base portion  31 , and a connecting portion  35  extending forwardly from the bottom end of the leg portion  34 . 
     The base portion  31  has formed therein press-fitting protrusions  31 A that protrude from the upper edge of the base portion  31  at an intermediate location and a rear end location in the forward-backward direction. The counterpart terminals  30  are retained in place within the counterpart housing  40  as a result of being press-fitted from the front into the hereinafter-described counterpart terminal-retaining groove portions  40 B- 1  of the counterpart housing  40  such that the press-fitting protrusions  31 A are brought into biting engagement with the inner surface of the counterpart terminal-retaining groove portions  40 B- 1  (see  FIG.  12    (A)). 
     The long arm portion  32  extends rearwardly from the top rear end edge of the base portion  31  and is resiliently deformable in the up-down direction. A rear counterpart contact portion  32 A, which is brought into contact with the contact portions C 1 A of the flat-type conductor C from above under contact pressure, is formed at the rear end of the long arm portion  32  so as to protrude downward in a substantially triangular configuration. In the up-down direction, the rear counterpart contact portion  32 A protrudes to substantially the same height as the hereinafter-described front counterpart contact portion  33 A of the short arm portion  33 . 
     The short arm portion  33 , which is positioned downwardly of the long arm portion  32  and extends rearwardly from the rear end edge of the vertically intermediate portion of the base portion  31 , is resiliently deformable in the up-down direction. A front counterpart contact portion  33 A, which is brought into contact with the contact portions C 1 A of the flat-type conductor C from above under contact pressure, is formed at the rear end of the short arm portion  33  so as to protrude downward in a substantially triangular configuration. The short arm portion  33  is made slightly shorter than the long arm portion  32 , and the front end of the short arm portion  33  is positioned forwardly (on side X 1 ) of the front end of the long arm portion  32 . In other words, the front counterpart contact portion  33 A of the short arm portion  33  is positioned forwardly of the rear counterpart contact portion  32 A of the long arm portion  32 . 
     As can be seen in  FIG.  11    (A) and  FIG.  12    (A), the rear counterpart contact portion  32 A and the front counterpart contact portion  33 A are located substantially at the same height and are positioned adjacent each other in the forward-backward direction. In addition, the rear counterpart contact portion  32 A and the front counterpart contact portion  33 A, which protrude past the bottom faces of the hereinafter-described nested portions  44  of the counterpart housing  40  and are positioned within the hereinafter-described counterpart receiving space  40 C, are enabled to contact the contact portions C 1 A of the flat-type conductor C. In the present embodiment, making a two-point contact with the contact portions C 1 A possible in this manner ensures an adequate state of contact with the contact portions C 1 A. 
     The leg portion  34  extends downwardly from the bottom edge of the base portion  31  in a linear manner. When the counterpart connector  2  is mounted to a circuit board (not shown), the connecting portions  35  are positioned at the same height as the corresponding circuits (not shown) formed on the mounting face of the circuit board and can be solder-connected to said corresponding circuits. 
     As can be seen in  FIG.  10   , the counterpart housing  40  has a substantially rectangular parallelepiped-like exterior configuration whose longitudinal direction is the connector width direction (Y-direction) and, as can be seen in  FIG.  12    (A), along with having a counterpart mating portion  40 A used for mating with the housing  10  of the connector  1  in substantially the rear half, has a counterpart terminal-retaining portion  40 B used for retaining the counterpart terminals  30  in place by press-fitting in substantially the front half. 
     The counterpart mating portion  40 A has a counterpart top wall  41  and a counterpart bottom wall  42  that serve as counterpart mating walls extending in the connector width direction and opposed in the up-down direction, a pair of counterpart lateral walls  43  extending in the up-down direction at the opposite ends in the connector width direction and coupling the counterpart top wall  41  to the counterpart bottom wall  42 , and nested portions  44  extending forwardly from the rear end face of the counterpart terminal-retaining portion  40 B through the interior space of the counterpart mating portion  40 A. The rearwardly open space enclosed by the counterpart top wall  41 , counterpart bottom wall  42 , and counterpart lateral walls  43  is formed to serve as a counterpart receiving space  40 C intended for receiving the mating portion  10 A of the connector  1 . 
     At three locations in the connector width direction, the counterpart top wall  41  has formed therein counterpart protruding walls  41 A- 41 C that protrude from the bottom face of the counterpart top wall  41  while extending in the forward-backward direction. Specifically, as can be seen in  FIG.  10   , the counterpart protruding walls  41 A- 41 C include a first counterpart protruding wall  41 A, a second counterpart protruding wall  41 B, and a third counterpart protruding wall  41 C arranged successively in a spaced relationship from side Y 1  to side Y 2 . The second counterpart protruding wall  41 B is made narrower in width than the first counterpart protruding wall  41 A and the third counterpart protruding wall  41 C. 
     The second counterpart protruding wall  41 B includes a main protruding wall  41 B- 1 , which protrudes to substantially the same dimension in the up-down direction as the first counterpart protruding wall  41 A and the second counterpart protruding wall  41 B and two auxiliary protruding walls  41 B- 2 , which protrude downwardly at two locations on the opposite sides of the main protruding wall  41 B- 1  in the connector width direction. 
     The first counterpart protruding wall  41 A is positioned in alignment with the space between the first protruding wall  11 A and the second protruding wall  11 B of the connector  1  in the connector width direction. The main protruding wall  41 B- 1  of the second counterpart protruding wall  41 B is positioned in alignment with the space between the second protruding wall  11 B and the third protruding wall  11 C in the connector width direction. The two auxiliary protruding walls  41 B- 2  of the second counterpart protruding wall  41 B are positioned in alignment with, respectively, the space between the locking arm portion  11 E- 1  and the second protruding wall  11 B, and the space between the locking arm portion  11 E- 1  and the third protruding wall  11 C of the connector  1  in the connector width direction. The third counterpart protruding wall  41 C is positioned in alignment with the space enclosed by the locking arm portion  11 E- 1 , third protruding wall  11 C, and fourth protruding wall  11 D of the connector  1  in the connector width direction. 
     In addition, a locking aperture  41 F, which extends through the counterpart top wall  41  in the up-down direction, is formed in the rear end portion of the counterpart top wall  41  at a central location in the connector width direction, i.e., at a location between the two auxiliary protruding walls  41 B- 2 . As described hereinafter, the locking aperture  41 F serves to prevent the decoupling of the connector  1  by engaging the locking protrusion  11 E- 2  of the connector  1  (see  FIG.  12    (B)). 
     As can be seen in  FIG.  10   , forwardly and downwardly open fitting-retaining groove portions  43 A extending in the forward-backward direction are formed in the counterpart lateral walls  43  in a slit-shaped configuration extending in a direction perpendicular to the connector width direction. 
     The nested portions  44  have a plurality of nested ridge portions  44 A arranged in the connector width direction within the respective array ranges of the previously discussed two counterpart terminal groups. The nested ridge portions  44 A are positioned between the counterpart terminals  30  and extend rearwardly from the rear face of the counterpart terminal-retaining portion  40 B. When the counterpart terminals  30  are retained in place within the counterpart housing  40 , the rear counterpart contact portion  32 A and front counterpart contact portion  33 A of the counterpart terminals  30  protrude downwardly past the bottom faces of the nested ridge portions  44 A. 
     As can be seen in  FIG.  12    (A), the counterpart terminal-retaining portion  40 B has formed therein counterpart terminal-retaining groove portions  40 B- 1  used for retaining the counterpart terminals  30  in place by press-fitting, which are formed through the counterpart terminal-retaining portion  40 B in the forward-backward direction. The counterpart terminal-retaining groove portions  40 B- 1 , which have a slit-shaped configuration extending perpendicular to the connector width direction, are formed in an array in the connector width direction. 
     As can be seen in  FIG.  11    (B), the anchor fittings  50  are made by bending a sheet metal member in the through-thickness direction. The anchor fittings  50  have a retained plate portion  51 , which has major faces perpendicular to the connector width direction and extends in the forward-backward direction, and an anchoring portion  52 , which is made by bending the bottom edge of the retained plate portion  51  at right angles at an intermediate location of the retained plate portion  51  in the forward-backward direction and which extends outwardly in the connector width direction. The retained plate portion  51  has two press-fitting protrusions  51 A protruding from the upper edge of the front end portion. As a result of being press-fitted into the fitting-retaining groove portions  43 A of the counterpart housing  40  from the rear such that the press-fitting protrusions  51 A are brought into biting engagement with the inner surface of the fitting-retaining groove portions  43 A, the anchor fittings  50  are retained in place within the counterpart housing  40 . The anchoring portions  52  are secured to corresponding portions (not shown) formed as pads on the mounting face of the circuit board by solder-connecting the bottom faces of the anchoring portions  52  to the corresponding portions. 
     The counterpart connector  2  is assembled in accordance with the following procedure. First, the base portions  31  of the counterpart terminals  30  are press-fitted into the counterpart terminal-retaining groove portions  40 B- 1  of the counterpart housing  40  from the front. In addition, the retained plate portions  51  of the anchor fittings  50  are press-fitted into the fitting-retaining groove portions  43 A of the counterpart housing  40  from the rear. As a result, the counterpart terminals  30  and anchor fittings  50  are retained in place within the counterpart housing  40 , which completes the assembly of the counterpart connector  2 . The order of attachment (press-fitting) of the counterpart terminals  30  and the anchor fittings  50  to the counterpart housing  40  is not limited to the order described above, and either may be attached first or, alternatively, the attachment may be simultaneous. 
     The connector  1  and counterpart connector  2  are matingly connected in accordance with the following procedure. First, the counterpart connector  2  is mounted to a circuit board (not shown) by solder-connecting the connecting portions  35  of the counterpart terminals  30  of the counterpart connector  2  to the corresponding circuits of the circuit board as well as solder-connecting the anchoring portions  52  of the anchor fittings  50  to the corresponding portions of the circuit board. 
     Next, as can be seen in  FIG.  1   , after positioning the connector  1  at the rear of the counterpart connector  2 , the connector  1  is moved forward, thereby mating the mating portion  10 A of the connector  1  with the counterpart mating portion  40 A of the counterpart connector  2  from the rear. 
     In the process of connector mating, the mating portion  10 A enters the counterpart receiving space  40 C from the rear and the locking protrusion  11 E- 2  of the locking arm portion  11 E- 1  abuts the rear end portion of the counterpart top wall  41  of the counterpart housing  40 , as a result of which it is resiliently displaced downward, enabling further advancement of the connector  1 . In addition, in the process of connector mating, the protruding walls  11 A- 11 D of the connector  1  enter the corresponding spaces in the counterpart connector  2  from the rear and the counterpart protruding walls  41 A- 41 C of the counterpart connector  2  enter the corresponding spaces in the connector  1  from the front. As a result, the fact that the misalignment of the protruding walls  11 A- 11 D in the connector width direction is limited by the counterpart protruding walls  41 A- 41 C ensures that the connector  1  is guided forward in an effortless manner. 
     As the connector  1  advances further and the locking protrusion  11 E- 2  reaches the location of the locking aperture  41 F of the counterpart top wall  41 , the locking arm portion  11 E- 1  returns to the free state and the locking protrusion  11 E- 2  enters the locking aperture  41 F from below. As a result, as can be seen in  FIG.  12    (A), the locking protrusion  11 E- 2  is enabled to rearwardly engage the inner surface of the locking aperture  41 F, thereby producing a locked state in which inadvertent decoupling of the counterpart connector  2  is prevented. 
     In addition, in the process of connector mating, the nested ridge portions  44 A of the nested portions  44  of the counterpart housing  40 , as well as long arm portions  32  and short arm portions  33  of the counterpart terminals  30  arranged by the nested ridge portions  44 A, enter the corresponding front receiving spaces  10 D, in other words, the respective front receiving spaces  10 D separated by the plurality of partition walls  14  in the connector  1  from the front. As a result, the long arm portions  32  and short arm portions  33 , while being resiliently deformed upward, are brought into contact with the contact portions C 1 A of the flat-type conductor C under contact pressure with the help of the rear counterpart contact portions  32 A and front counterpart contact portions  33 A (see  FIG.  12    (A)). As a result, the flat-type conductor C and counterpart terminals  30  are placed in electrical communication. 
     Although in  FIG.  12    (A) the arm portions  32 ,  33  are illustrated in a state in which none of them is subject to resilient deformation and the counterpart contact portions  32 A,  33 A overlap with the contact portions C 1 A of the flat-type conductor C, in actual fact, as discussed previously, the arm portions  32 ,  33  are subject to resilient deformation and the counterpart contact portion  32 A,  33 A are brought into contact with the protruding apex portions of the contact portions C 1 A of the flat-type conductor C. 
     In addition, the top ridge portions  11 F of the front top wall  11  of the connector  1  and the bottom ridge portions  12 A of the front bottom wall  12  are brought into biting engagement with the bottom face of the counterpart top wall  41  and the top face of the counterpart bottom wall  42 , respectively, and assist in positioning both connectors  1 ,  2  in the connector width direction as well as in the up-down direction. 
     Although in the present embodiment the locking portion  11 E of the connector  1  is provided with a single locking arm portion  11 E- 1 , alternatively, the locking portion may include a plurality of locking arm portions positioned in a spaced relationship in the connector width direction. Providing a plurality of locking arm portions in this manner allows for front receiving spaces to be formed in the housing at locations between mutually adjacent locking arm portions, as a result of which the number of circuits of the flat-type conductor and, by extension, the number of the counterpart terminals of the counterpart connector can be increased without making the connector larger in the connector width direction. In addition, forming thin locking arm portions makes it easier for the locking arm portions to undergo resilient deformation. 
     Although in the present embodiment the locking portion  11 E was provided at a location that is within a range overlapping with the receiving spaces  10 D,  10 E of the housing  10  in the forward-backward direction, alternatively, the locking portion may be provided rearwardly of the receiving spaces without overlapping with the receiving spaces in the forward-backward direction. Even if the locking portion is provided rearwardly of the receiving spaces in this manner, as long as the locking portion is positioned within a range overlapping with the receiving spaces in the up-down direction, connector profile reduction will be achieved in exact proportion to the overlap. 
     Although in the present embodiment the overlap of the locking portion  11 E with the receiving spaces  10 D,  10 E in the up-down direction was confined to a portion, specifically, a bottom portion of the locking arm portion  11 E- 1 , alternatively, the entire locking arm portion may be made to overlap with the receiving spaces in the up-down direction and, furthermore, the entire locking portion may be made to overlap with the receiving spaces in the up-down direction. In this manner, the effect of connector profile reduction is improved in exact proportion to the increase in the size of the overlap between the locking portion and the receiving spaces. 
     Although in the present embodiment the flat-type conductor C is a whole, single flat-type conductor that is not split in the connector width direction, alternatively, the flat-type conductor may be formed as multiple flat-type conductor units split in the connector width direction. In such a case, the multiple flat-type conductor units can be adjacent in a spaced relationship in the connector width direction, and the ranges of the intervals therebetween can be used as circuit-free ranges. If the circuit-free ranges are formed in this manner between the flat-type conductor units, then locking portions can be formed in the housing within the circuit-free ranges in the connector width direction. In addition, notched portions that open toward each other in the connector width direction can be formed in the respective lateral edge portions (edge portions extending in the forward-backward direction) of two mutually adjacent flat-type conductor units positioned on the opposite sides of a circuit-free range to serve as a pass-through portion, and the protrusion of the retainer can be introduced into this pass-through portion in the up-down direction. As a result, the protrusion will be able to engage the front end edge of each notched portion from the rear and will be able to prevent inadvertent decoupling by limiting the rearward movement of each flat-type conductor unit. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
           1  Connector (electrical connector with a flat-type conductor) 
           2  Counterpart connector (counterpart electrical connector) 
           10  Housing 
           10 D Receiving spaces 
           10 E Rear receiving space (holding space) 
           11 E Locking portion 
           11 E- 1  Locking arm portion 
           11 E- 2  Locking protrusion (locking engagement portion) 
           17  Rear bottom wall 
           17 A Limiting recessed portion (recessed portion) 
           20  Retainer 
           21 C Protrusion 
           21 C- 1  Protruding apex portion 
         C Flat-type conductor 
         C 1  Circuits 
         C 3  Pass-through portion