Patent Publication Number: US-7722414-B2

Title: Connector having separately made lance housing and retainer

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a connector. 
   2. Description of the Related Art 
   Japanese Unexamined Patent Publication No. H09-161875 discloses a connector that has a housing formed with cavities for receiving terminal fittings. Resiliently deformable locking lances project at inner surfaces of the cavities for locking the terminal fittings in the cavities. A retainer is arranged on the front surface of the housing and has terminal locks that fit into deformation spaces for the locking lances. The terminal locks of the retainer restrict resilient deformations of the locking lances to achieve double locking of the terminal fittings. A guide projects from the front surface of the housing and a fitting portion penetrates the retainer. The guide is inserted into the fitting portion as the retainer is assembled. 
   Resin flowability decreases during molding a housing for a multipolar connector. Therefore it is difficult to mold a unitary housing that has small locking lances and the like. 
   The invention was developed in view of the above situation and an object thereof is to allow a connector to have an improved moldability while having a good operability. 
   SUMMARY OF THE INVENTION 
   The invention relates to a connector with a housing main body formed with one or more cavities for receiving terminal fittings. At least one lance housing is provided separately from the housing main body and is formed with one or more terminal insertion holes that communicate with the respective cavities when the lance housing is arranged on the housing main body. The lance housing has one or more resiliently deformable locking lances that correspond to the terminal insertion holes. The locking lances retain the terminal fittings inserted into the terminal insertion holes. A retainer is provided separately from the lance housing and includes one or more terminal locks that can enter deformation spaces for the respective locking lances engaged with the terminal fittings when the retainer is arranged on the lance housing. 
   At least one projection preferably projects from the retainer and at least one receiving hole is formed in the lance housing for receiving the projection. The lance housing and the retainer are positioned with respect to each other by inserting the projection into the respective receiving hole. 
   The projection preferably projects backward from the retainer and the receiving hole preferably is formed in the front surface of the lance housing. Thus, a positional relationship of the lance housing and the retainer is determined precisely and the retaining function of the retainer is exhibited correctly. Additionally, the leading end of the projection can be fit into the insertion hole as the retainer is assembled. 
   The engagement of the projection with the lance housing and the housing main body suppresses shaking movements of the retainer and ensures proper positioning of the retainer, the lance housing and the housing main body. 
   The retainer preferably is displaceable between a partly locked state and a fully locked state. The locking lances are permitted to deform when the retainer is in the partly locked state so that the terminal fittings can be inserted into the cavities and withdrawn from the cavities. The locking lances cannot deform when the retainer is in the fully locked state so that the properly inserted terminal fittings are locked redundantly in the cavities. 
   The leading end of the projection preferably is fit in the insertion hole when the retainer is both in the partly locked state and in the fully locked state. 
   The retainer is stable without shaking not only in the fully locked state, but also in the partly locked state. When the retainer moves from the partly locked state to the fully locked state, the projection is smoothly inserted into the insertion hole without getting caught by the hole edge of the insertion hole. 
   The projection preferably includes at least a first part extending in a first direction and at least a second part extending in a second direction intersecting the first direction. At least one rib is provided at a position back to back with the projection, with a main body of the retainer located therebetween. 
   The first direction preferably is a height direction and the second direction preferably is a width direction. 
   The projection preferably has a cross-shaped cross section and is at or near a central part of the rear surface of the retainer. Thus, a reduction in the effective space of the retainer can be suppressed to a minimum necessary level as compared with the case where the projection is provided over a wide range of the rear surface of the retainer. Further, the cross-shaped cross section ensures sufficient strength for the projection, while also suppressing shaking movements in the height and width directions and hindering pivotal movements of the lance housing about an axis of the projection. 
   These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of one embodiment of the invention when a lance housing and a retainer are assembled with a housing main body. 
       FIG. 2  is a front view of the housing main body. 
       FIG. 3  is a rear view of the housing main body. 
       FIG. 4  is a horizontal section when the retainer is assembled with the housing main body and the lance housing. 
       FIG. 5  is a section along A-A of  FIG. 1  and FIG  5 A is a cross-section similar to  FIG. 5 , but showing the retainer in a fully locked state. 
       FIG. 6  is a horizontal section when the retainer is properly assembled with the housing main body and the lance housing. 
       FIG. 7  is a side view in section of the housing main body. 
       FIG. 8  is a front view of the lance housing. 
       FIG. 9  is a rear view of the lance housing. 
       FIG. 10  is a side view in section of the lance housing. 
       FIG. 11  is an enlarged view showing an essential part of  FIG. 10 . 
       FIG. 12  is a rear view of the retainer. 
       FIG. 13  is a front view of the retainer. 
       FIG. 14  is a bottom view of the retainer. 
       FIG. 15  is a side view of the retainer. 
       FIG. 16  is a side view in section of the retainer. 
       FIG. 17  is a rear view of a female connector housing. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A male connector in accordance with the invention is illustrated in  FIGS. 1 to 17  and is identified generally by the numeral  10 . The connector  10  connectable with a mating female connector  100  and is provided with a housing main body  20 , a lance housing  50 , a retainer  70  and male terminal fittings  90 . The housing main body  20 , the lance housing  50  and the retainer  70  are made e.g. of a synthetic resin or different synthetic resins and the male terminal fittings  90  are made of an electrically conductive material such as metal. In the following description, an end to be connected with the mating female connector  100  is referred to as the front end concerning forward and backward directions FBD and reference is made to  FIG. 1  concerning vertical direction. 
   The housing main body  20  cooperates with the lance housing  50  to form a connector housing and includes a terminal accommodating portion  22  formed with cavities  21  for accommodating the respective male terminal fittings  90  and a wide tubular receptacle  23  projects forward from the peripheral edge of the front surface of the terminal accommodating portion  22  as shown in  FIGS. 2 and 7 . Tabs  91  of the respective male terminal fittings  90  are arranged to project into the receptacle  23 , and upper and lower cam followers  24  project from the outer surfaces of the opposite upper and lower walls of the receptacle  23  for exhibiting a cam action by a connecting operation with the mating female connector  100 . A stay lock  25  projects behind the upper cam follower  24  in a widthwise central part of the housing main body  20  and is engageable with an unillustrated bracket. 
   Two large cavities  26  are provided at each of the opposite widthwise sides of the terminal accommodating portion  22  for accommodating large male terminal fittings  90 . The large cavities  26  in each pair are arranged one above the other in a vertical direction and vertically resiliently deformable locking lances  27  project at the front ends of the inner surfaces of the large cavities  26 . 
   The front surface of a widthwise intermediate part of the terminal accommodating portion  22  is retracted slightly back from the front surfaces of the large cavities  26  located in the widthwise end parts. Thus, a mount space  28  for the lance housing  50  is formed between the opposite inner surfaces of the widthwise end parts and has a substantially having a rectangular shape when viewed from the front. Small cavities  29  are arrayed in vertical and width directions in the widthwise intermediate part of the terminal accommodating portion  22  for accommodating small male terminal fittings  90 . The small cavities  29  are arranged in upper and lower levels at each of the opposite sides of a vertical central part. No locking lances  27  are formed at inner surfaces of the small cavities  29 . 
   Claw-shaped lance housing locks  30  project on the inner surfaces of opposite upper and lower walls of the mount space  28  of the terminal accommodating portion  22  for retaining the lance housing  50 . A bottomed insertion hole  31  is formed in the front surface of a widthwise intermediate part of the terminal accommodating portion  22  at a position corresponding to a intermediate part of the housing main body  20  in the width and vertical directions. The insertion hole  31  is substantially cross-shaped in a front view and is comprised of a long vertical groove  32  and a short horizontal groove  33 . The vertical and horizontal grooves  32 ,  33  cross at right angles at a position slightly above the vertical center and communicate with each other. It should be understood that the insertion hole  31  may have a different configuration (e.g. the grooves  32 ,  33  may cross at a different angle) and may be oriented differently (e.g. the insertion hole  31  may be rotated around its axis). 
   As shown in  FIGS. 3 and 4 , bores  34  are provided at a rear part of the terminal accommodating portion  22  for preventing the formation of sinks. Right cylindrical seal towers  35  project back by the bores  34 . The seal towers  35  are at positions corresponding to the respective cavities  21  and are circular enclosures surrounding the cavities  21 . A sealing plug  96  is fit on an end of a wire  95  connected with the male terminal fitting  90  and seals to the inner circumferential surface of each seal tower  35 . Thus, the insides of the seal towers  35  and the inside of the housing main body  20  are sealed hermetically. 
   A wide tubular surrounding wall  36  is provided on a rear part of the housing main body  20  and surrounds the seal towers  35 . Ribs  37  are provided inside this surrounding wall  36 . The surrounding wall  36  forms the outer wall of the housing main body  20  and is open backward toward a side opposite to the receptacle  23 . 
   The seal towers  35  include small seal towers  38  corresponding to the small cavities  29  and large seal towers  39  corresponding to the large cavities  26 . The small seal towers  38  are at positions corresponding to the small cavities  29  in the widthwise intermediate middle part. Thus, the small seal towers  38  are arranged in upper and lower levels at each of the opposite sides of a vertical central part and at the opposite left and right sides of a widthwise central part. Two large seal towers  39  are arranged one above the other near each of the opposite widthwise end sides. Some of the small seal towers  38  are united unitarily in the width direction via common thin walls  40 . The centers of the upper large seal towers  39  substantially align with a plane between the two upper levels of small seal towers  38 . On the other hand, the vertical centers of the lower larger seal towers  39  are above a plane between the two lower levels of small seal towers  38 . 
   The length of the small seal towers  38  in forward and backward directions FBD substantially equals the length of the surrounding wall  36  and the ribs  37 . The front and rear ends of the small seal towers  38  are aligned substantially at the same positions as the front and rear ends of the surrounding wall  36  and the ribs  37  and the rear surfaces of the small seal towers  38  form the rear surface of the housing main body  20  together with those of the surrounding wall  36  and the ribs  37 . On the other hand, the front ends of the large seal towers  39  are at substantially the same positions as the front ends of the small seal towers  38 , but the rear ends thereof are more backward than rear ends of the small seal towers  38 . The small seal towers  38  are thinner than the large seal towers  39  and also are thinner than the surrounding wall  36  and the minimum dimension of the ribs  37 . 
   The ribs  37  extend between the inner surfaces of the surrounding wall  36  like a lattice and include the outer ribs  41 , a main rib  42 , inner ribs  43  and connecting ribs  44 . The outer ribs  41  extend between the inner surfaces of the surrounding wall  36  and the outer surfaces of the seal towers  35 . The main rib  42  extends between the opposite inner side surfaces of the surrounding wall  36  and crosses the vertical central part of the surrounding wall  36  in the width direction. The inner ribs  43  extend between the main rib  42  and the outer surfaces of the seal towers  35  and the connecting ribs  44  connecting the adjacent seal towers  35 . 
   Each outer rib  41  is thick at the connection with the surrounding wall  36  and thin at its connection with the seal tower  35 . More specifically, each outer rib  41  has a tapered section  45  gradually narrowed toward the seal tower  35  from the connection with the surrounding wall  36 . A straight section  46  extends straight from the leading end of the tapered section  45  to the seal tower  35 . Thus, the opposite side surfaces of the tapered section  45  and those of the straight section  46  are at obtuse angles to each other. The outer ribs  41  extend vertically between opposite upper and lower walls of the surrounding wall  36  and the seal towers  35  facing these walls and are outward (directions orthogonal to tangents) of the seal towers  35  while being spaced apart at specified intervals in the width direction. The maximum thickness of the outer ribs  41  where the tapered sections  45  connected with the surrounding wall  36  exceeds thicknesses of the other ribs  42 ,  43 , and  44 . The minimum thickness of the outer ribs  41  on the straight sections  46  is substantially equal to thicknesses of the inner ribs  43  and the connecting ribs  44 . 
   The main rib  42  is comprised of first main ribs  47  arranged to cross substantially straight in the width direction between the upper and lower large seal towers  39  from the opposite inner side surfaces of the surrounding wall  36 , at least one second main rib  48  crossing substantially straight in the width direction between the respective small seal towers  38  at the upper and lower stages and third main ribs  49  extending obliquely straight with a downward gradient from the first main ribs  47  to the second main rib  48 . The first, second and third main ribs  47 ,  48  and  49  have the same thickness, which are slightly smaller than the maximum thicknesses of the outer ribs  41 , but larger than the minimum thicknesses of the outer ribs  41 . 
   One or more gates (not shown), are provided at the substantially opposite lateral outer sides of the surrounding wall  36  for receiving molten resin while molding the housing main body  20 . The main rib  42  is near these gates so that the molten resin injected from the gates can flow in its injection directions. 
   The inner ribs  43  extend vertically between the second main rib  48  and the small seal towers  38  facing the second main rib  48  and between the first main ribs  47  and the large seal towers  39  facing the first main ribs  47 . The inner ribs  43  are arranged at the same intervals as the outer ribs  41  in the width direction. The inner ribs  43  are arranged vertically symmetrically with respect to the second main rib  48  and are inward of the seal towers  35 . The inner and outer ribs  43  and  41  are on substantially straight lines passing the centers of the seal towers  35 . Thus, the inner and outer ribs  43  and  41  vertically cross the inside of the surrounding wall  36  via the seal towers  35  and the inner ribs  43  and the main rib  42  are connected substantially at right angles to each other. 
   The connecting ribs  44  extend between the adjacent seal towers  35  that are separated without being connected by the thin walls  40  and have lengths corresponding to distances between the adjacent seal towers  35 . Each connecting rib  44  is located on a straight line connecting the centers of the adjacent seal towers  35  and is connected with the outer circumferential surfaces of the seal towers  35  substantially at right angles to tangent directions to these outer circumferential surfaces. 
   The small seal towers  38  adjacent to each other are arranged substantially side by side in the width direction and, thus, the connecting ribs  44  extending between the respective small seal towers  38  are arranged substantially horizontally in the width direction. Longer horizontal connecting ribs  44  are connected with the inner ribs  43  substantially at right angles at intermediate positions. The centers of the small seal towers  38  located at the opposite widthwise ends in the two upper levels and those of the upper large seal towers  39  are displaced vertically. Therefore the connecting ribs  44  extending between the small seal towers  38  in the two upper levels and the upper large seal towers  39  are arranged obliquely with respect to the horizontal direction. On the other hand, the connecting ribs  44  extending between those of the small seal towers  38  in the two lower levels located right below the main rib  42  and located at the opposite widthwise ends and the lower large seal towers  39  are arranged obliquely with a small upward gradient from the centers of the small seal towers  38  to the lower large seal towers  39 . There are no connecting ribs  44  extending between the seal towers  38  in the bottommost level and the large seal towers  39 . 
   As shown in  FIG. 17 , the rear surface of a female housing  101  of the mating female connector  100  also has seal towers  35 , a surrounding wall  36 , outer ribs  41  including tapered sections  45  and straight sections  46  and connecting ribs  44 . 
   The lance housing  50  is assembled into the mount space  28  of the housing main body  20  and retained by the lance housing locks  30  in a properly assembled position. Specifically, as shown in  FIGS. 8 to 11 , the lance housing  50  faces the front surface of the housing main body  20  at the back of the mount space  28 . The lance housing  50  has a substantially plate-like lance housing main body  52  with terminal insertion holes  51  that communicate with the respective small cavities  29  as the lance housing  50  is assembled. Tubular cavity towers  53  are arranged at positions corresponding to the terminal insertion holes  51  and project forward from the front surface of the lance housing main body  52 . Locking lances  27  are located in the respective cavity towers  53  and project forward from the front surface of the lance housing main body  52 . Substantially plate-like lance housing interlocking portions  54  project forward from the opposite upper and lower ends of the lance housing main body  52 . Locking claws  55  project out from the lance housing interlocking portions  54  and engage resiliently with the lance housing locks  30  of the housing main body  20  to retain the lance housing  50  in the mount space  28 . 
   Each cavity tower portion  53  has a horizontal plate-shaped upper wall  56  that extends in forward and backward directions FBD, opposite side walls  57  hang vertically down from opposite lateral edges of the upper wall  56  and a front wall  58  connects the front ends of the upper wall  56  and the opposite side walls  57  to close the front. A terminal insertion hole  51  is defined by the inner space between the upper wall  56 , the side walls  57  and front wall  58  and is substantially continuous with the lance housing main body  52 . The male terminal fitting  90  is insertable into the terminal insertion hole  51  from the side of the cavity  21 . The front openings of the terminal insertion holes  51  forming the front ends of the cavity towers  53  are aligned substantially at the same positions as the front openings of the large cavities  26  with respect to forward and backward directions FBD. Posture maintaining ribs  59  extend in forward and backward directions FBD on the inner surfaces of the opposite side walls  57  and prevent the male terminal fitting  90  from inclining forward. The side surfaces of the male terminal fitting  90  can slide on the posture maintaining ribs  59  to hold the male terminal fitting  90  in a desired horizontal posture. A tab insertion hole  60  penetrates the front wall  58  in forward and backward directions FBD for permitting insertion of the tab  91  of the male terminal fitting  90 . The inner surface of the tab insertion hole  60  defines a conical guiding surface  60  that widens toward the rear surface of the front wall  58 . 
   Each locking lance  27  face the inner surface of the upper wall  56  of the cavity tower  53  and projects from a base end thereof connected with the lance housing main body  52  substantially toward the terminal insertion hole  51 . The locking lance  27  is vertically resiliently deformable in a direction intersecting an insertion direction of the terminal fitting  90  into the cavity  21  with the base end connected with the lance housing main body  52  as a support. A deformation space  63  for the locking lance  27  is formed between the locking lance  27  and the lower and adjacent cavity tower  53  or a plate-like lower stay portion  62  that projects forward from the bottom end of the front surface of the housing main body  20 . A locking projection  64  is provided near the leading end of the upper surface of the locking lance  27  projecting into the terminal insertion hole  51 . The width of the locking lance  27  is substantially equal to the width of the upper wall  56  of the cavity tower  53 , so that the locking lance  27  is small, but sufficiently strong. An engaging rib  65  extends in forward and backward directions FBD in a widthwise intermediate position of the lower surface of the locking lance  27  to further increase the strength of the locking lance  27 . 
   A first error connection preventing rib  66  projects from one lateral edge of the lance housing main body  52  for direction discrimination of the lance housing  50 . This first error connection preventing rib  66  fits into an error connection preventing rib receiving recess  19  formed in the front surface of the housing main body  20 . Thus, the lance housing  50  is prevented from being assembled erroneously with the housing main body  20 . 
   Three openings are formed one above another in a widthwise intermediate part of the lance housing main body  52 , and the cavity towers  53  and the locking lances  27  are arranged at the opposite left and right sides of these openings. The openings penetrate a reinforcing rib  67  projecting from the front surface of the lance housing main body  52  in forward and backward directions FBD. The upper and lower openings define auxiliary receiving holes  68  for receiving auxiliary projections  64  of the retainer  70 , and the middle opening defines a receiving hole  69  for receiving a projection  75  of the retainer  70 . The auxiliary receiving holes  68  are vertically long and substantially rectangular. The receiving hole  69  is a substantially cross-shaped opening corresponding to the insertion hole  31  and aligns with the insertion hole  31  as the lance housing main body  52  is assembled with the housing main body. 
   The retainer  70  is arranged to face the front surface of the lance housing  50  and includes a substantially plate-like retainer main body  72  formed with fitting windows  71  for receiving the cavity towers  53  and the locking lances  27  when the retainer  70  is assembled with the lance housing  50 , as shown in  FIGS. 12 to 16 . The retainer  70  also includes connection ribs  73  that project forward from the front surface of the retainer main body  72 , auxiliary projections  74  and a projection  75  that project back from a widthwise intermediate part of the rear surface of the retainer main body  72 , and slide plates  76  that are slidably fittable to the inner surfaces of the lance housing locks  54  and the side surfaces of the cavity towers  53  as the retainer  70  is assembled. 
   Upon assembling the retainer  70 , the slide plates  76  are slidable while substantially being held between the inner surfaces of the mount space  28  of the housing main body  20  and the outer surfaces of the lance housing  50 . A second error connection preventing rib  77  projects from a lateral edge of the slide plate  76  for direction discrimination of the retainer  70 . This second error connection preventing rib  77  fits into the error connection preventing rib recess  19  of the housing main body  20  while being united with the first error connection preventing rib  66 . Thus, the retainer  70  is prevented from being assembled erroneously with the housing main body  20 . 
   The cavity towers  53  fit individually into the fitting windows  71 , which are defined by a lattice  88  that projects from the rear surface of the retainer main body  72 . The front surfaces of the cavity towers  53  are arranged at the same positions as the front surfaces of the fitting windows  71  with respect to forward and backward directions FBD in a properly assembled state with the lance housing  50 . Thus, front surfaces of the terminal insertion holes  51  are at the front end of the retainer main body  72 . A terminal lock  78  is provided at a position of a lateral edge of the fitting window  71  corresponding to each locking lance  27  of the lance housing  50  and enters the deformation space  63  for the locking lance  27  in the properly assembled state. A rearwardly-open engaging groove  79  is formed in a widthwise intermediate part of each terminal lock  78  to permit the engaging rib  65  of the locking lance  27  to escape. The engaging rib  65  fits into the engaging groove  79  to prevent widthwise loose movements of the locking lance  27 . 
   The connection ribs  73  include a first connection rib  80  located in a widthwise intermediate part of the front surface of the retainer main body  72  and having a vertically long cross-shaped cross section, a second connection rib  81  located on the right side of the front surface of the retainer main body  72  and having an inverted T-shaped cross section with a long horizontal section, and a third connection rib  82  located on the left side of the front surface of the retainer main body  72  and having a wide cross-shaped cross section. The first, second and third connection ribs  80 ,  81  and  82  are arranged in dead spaces where no fitting windows  71  are provided, and are shaped in conformity with the shapes of the dead spaces. The connection ribs  73  can enter connection rib receiving portions (not shown) formed in the female connector  100  to guide a connecting operation as the connector is connected with the mating female connector  100 , and contact the front surface of the female connector  100  to prevent an erroneous connection of the two connectors  10 ,  100  if the female connector  100  is not in a proper posture. 
   The auxiliary projections  74  have projecting distances so that their leading ends reach the rear ends of the auxiliary receiving holes  68  of the lance housing  50  upon insertion into the auxiliary receiving holes  68 . However, the projection  75  has a projecting distance so that its leading end is inserted into the insertion hole  31  of the housing main body  20  through the receiving hole  69  of the lance housing  50  upon being inserted into the receiving hole  69 . The auxiliary projections  74  have a rectangular frame-shaped cross section, and hollow portions  83  with open rear ends are formed inside them. 
   The projection  75  has a substantially cross-shaped cross section conforming to the receiving hole  69  and the insertion hole  31  and is in a back-to-back relationship with the first connection rib  80  with the retainer main body  72  located therebetween. Specifically, the projection  75  is comprised of a long narrow vertical rib  84  that extends back with a projecting distance that is larger (preferably several times as large) as projecting distances of the auxiliary projections  74  and the slide plates  76 , and a short horizontal rib  85 . The vertical rib  84  and the horizontal rib  85  are connected with each other at substantially right angles at a position slightly above the vertical center. A slanted surface  86  is formed over the entire periphery of the leading end surface of the projection  75  for smooth insertion into the receiving hole  69  and the insertion hole  31 . 
   Molten resin is injected through the unillustrated gates upon molding the housing main body  20 . The molten resin then flows from the surrounding wall  36  toward the seal towers  35  via the outer ribs  41 . The tapered sections  45  at the outer ribs  41  guide the flowing molten resin smoothly toward the seal towers  35 . The molten resin also flows smoothly toward the seal towers  35  via the main rib  42  and the inner ribs  43  as another route. Thus, a molding failure occurrence rate can be suppressed by the presence of the ribs  37  even if the seal towers  35  are thin. 
   The lance housing  50  is fit into the mount space  28  of the housing main body  20  and is retained in the housing main body  20  by the resilient engagement of the lance housing locks  30  and the lance housing interlocking portions  54 . The first error connection preventing rib  66  of the lance housing  50  then enters the error connection preventing rib receiving portion  19  and the receiving hole  69  of the lance housing  50  is aligned with the insertion hole  31 . In this state, the male terminal fittings  90  are inserted into the cavities  21  from behind. The large male terminal fittings  90  then are locked by the locking lances  27  of the large cavities  26  and the tabs  91  at the leading ends thereof project into the receptacle  23 . The small male terminal fittings  90  are arranged from the cavities  21  to the terminal insertion holes  51  and retained by the locking lances  27  of the terminal insertion holes  51 , and the tabs  91  at the leading ends thereof project into the receptacle  23  through the tab insertion holes  60 . As the male terminal fittings  90  are mounted, the plugs  96  mounted on the ends of the wires  95  are accommodated into the seal towers  35 . Inner circumferential surfaces of the sealing plugs  96  closely contact the outer circumferential surfaces of the wires  95  while outer circumferential surfaces of the sealing plugs  96  contact the inner circumferential surfaces of the seal towers  35 . 
   The retainer  70  is arranged on the front surface of the lance housing  50  and is held in a partly locked state while the male terminal fittings  90  are being mounted. In this partly locked state, the terminal locks  78  of the retainer  70  are arranged at front positions so as not to enter the deformation spaces  63  for the locking lances  27 , as shown in  FIG. 5 . Thus, the locking lances  27  can deform so that the male terminal fittings  90  can be inserted. 
   The retainer main body  72  covers the front surface of the lance housing main body  52  when the retainer  70  is mounted. Additionally, the cavity towers  53  are fit into the fitting windows  71  of the retainer main body  72  and the projection  75  aligns with and fits into the receiving hole  69 , as shown in  FIG. 4 . The cross shapes of the projection  75  and the receiving hole  69  prevent rotational movements of the retainer  70  about an axis relative to the lance housing  50  in the process of mounting the retainer  70 . 
   Subsequently, as shown in  FIGS. 5A and 6 , the retainer  70  is pushed deeply into the receptacle  23  to reach a properly assembled state. Then, the terminal locks  78  enter the deformation spaces  63  for the locking lances  27  to restrict resilient deformations of the locking lances  27 . Thus, the male terminal fittings  90  are locked doubly locked. Further, the second error connection preventing rib  77  of the retainer  70  is fit to a proper depth into the error connection preventing rib receiving portion  19  and the projection  75  is inserted to a proper depth into the insertion hole  31  from the receiving hole  69 . As a result, the retainer  70  is positioned with respect to the lance housing  50  and the housing main body  20 . In this case, the retainer  70  is pushed smoothly by pushing the leading ends of the connection ribs  73  projecting from the front surface of the receptacle  23  in the partly locked state. Thereafter, the female housing  101  of the mating female connector  100  is fitted into the receptacle  23  while being guided by the connection ribs  73  to establish an electrical connection between the two connectors. 
   The projection  75  is provided on the retainer  70  and the receiving hole  69  is formed in the lance housing  50 . Thus, the lance housing  50  is positioned with respect to the retainer  70  by inserting the projection  75  into the receiving hole  69 . Accordingly, a mutual positional relationship of the lance housing  50  and the retainer  70  is determined precisely, and displacements of the terminal locks  78  from positions for insertion into the deformation spaces  63  for the locking lances  27  can be prevented as illustrated in  FIG. 5A . As a result, a primary function of the retainer  70  is exhibited correctly. 
   The projection  75  penetrates through the lance housing  50  and the leading end thereof is fit into the insertion hole  31 . Thus, an area of engagement of the projection  75  with the lance housing  50  and the housing main body  20  is increased to suppress shaking movements of the retainer  70 . In this way, the retainer  70 , the lance housing  50  and the housing main body  20  are positioned at proper positions. 
   The leading end of the projection  75  is fit in the insertion hole  31  even when the retainer  70  is in the partly locked state Thus, the retainer  70  constantly is held stably without shaking. When the retainer  70  moves from the partly locked state to the properly assembled state, the projection  75  can be inserted smoothly into the insertion hole  31  without getting caught by the edge of the insertion hole  31 . 
   Only one projection  75  is provided in the central part of the rear surface of the retainer main body  72 . Thus, a reduction in the effective space of the retainer can be suppressed to a minimum necessary level as compared with the case where the projection  75  is provided over a wide range of the rear surface of the retainer main body  72 . Further, by forming the projection  75  to have a cross-shaped cross section (or a shape not being rotationally symmetric thus defining a specified orientation around the longitudinal axis), sufficient strength can be ensured, shaking movements in the height and width directions can be reliably suppressed, and pivotal movements of the lance housing  50  about the axis of the projection  75  can be hindered. 
   The outer ribs  41  preferably are thicker at the connected parts with the surrounding wall portion  36 . Thus, resin can flow more easily toward the seal towers  35  to make a molding failure less likely. On the other hand, the outer ribs  41  are thinner at the connections with the seal towers  35 . Thus, sinks will not form in the seal tower portions  35 . 
   the outer ribs  41  are formed over the entire lengths of the surrounding wall  36  and the smaller seal towers  38  in forward and backward directions. Thus, resin flow is more improved. 
   The outer ribs  41  include the tapered sections  45  narrowed toward the seal towers  35  from the surrounding wall  36  to form guides for the resin toward the seal towers  35 . Thus, resin flow is improved even more. The outer ribs  41  include the straight sections  46  extending substantially straight from the leading ends of the tapered sections  45  to the seal towers  35 . Thus, sinks are not formed in the seal towers  35  during molding. 
   The seal towers  35  are thinner than the minimum dimension of the outer ribs  41 . Thus, sinks in the seal tower portions  35  can be more reliably avoided. 
   The inner ribs  43  extend between the outer surfaces of the main rib  42  dividing the respective seal towers  35  into at least upper and lower groups and the outer surfaces of the seal towers  35 . Thus, the lengths of the inner ribs  43  can be shorter to further improve resin flow as compared with the case where the inner ribs  43  directly bridge between the respective seal tower portions divided into the two upper and lower groups. 
   Adjacent seal towers  35  are connected to each other by the connecting ribs  44 . Thus, the adjacent seal towers  35  can be held with sufficient strength. On the other hand, the connecting ribs  44  are located on the substantially straight lines connecting the centers of the adjacent seal tower portions  35 . Thus, connection margins between the connecting ribs  44  and the seal towers  35  are not larger than necessary. As a result the formation of sinks in the seal towers  35  can be more reliably avoided to allow a retainer to exhibit its original function in the case of separately providing a housing main body and a lance housing. 
   The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments are also embraced by the technical scope of the present invention as defined by the claims. 
   Plural projections may project at arbitrary positions of the retainer. 
   It is sufficient for the projection to be so shaped to position the lance housing with respect to the retainer, and the projection may have, for example, a polygonal cross section. 
   The projection may be fit only into the receiving hole of the lance housing and may not be engaged with the housing main body. 
   The projection may include a part extending in the width direction and a part extending in the height direction (e.g. cross shape, T shape, L shape or shape formed by both parts not intersecting with each other) and may be provided at a position back to back with the connection rib with the retainer main body therebetween to utilized space can effectively. 
   The lance housing and the housing main body may be provided in a female connector accommodating female terminal fittings. 
   The thickness of the seal towers may be equal to the minimum dimension of the outer ribs. 
   It is sufficient for the connected parts of the outer ribs with the surrounding wall to be thicker than the connected parts thereof with the seal towers and the outer ribs may not necessarily include the tapered sections. 
   It is sufficient for the connected parts of the outer ribs with the seal towers to be thinner than the connected parts thereof with the surrounding wall portion and the outer ribs may not necessarily include the straight sections. 
   The surrounding wall portion and the seal towers may be intermittently continuous by being formed with cuts in some parts. 
   One main rib divides the seal towers into upper and lower groups in the height direction in the above embodiment. However, the main rib can have other shapes. For example, plural main ribs may divide the plurality of seal towers into a plurality of groups in the height direction. Alternatively, one or more main ribs may divide the seal towers into two or more groups in the width direction. Further, the seal towers may be divided into four groups by one main rib extending in the height direction and one main rib extending in the width direction. Furthermore, the main rib may extend obliquely to the height direction and the width direction.