Patent Publication Number: US-6702628-B2

Title: Connector and a method of assembling it

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a connector with a front holder. 
     2. Description of the Related Art 
     A connector has a housing with cavities and locks that are cantilevered from inner walls of the cavities. Terminal fittings are inserted into cavities and are locked by the cantilevered locks. The terminal fittings and the cavities easily can be made narrower to achieve miniaturization. However, the locks must be sufficiently strong to lock the terminal fittings. Thus, the locks must be substantially as wide as the cavities. As a result, supports for supporting the opposite sides of the front ends of the terminal fittings cannot be provided in an area where the cavities and the locks face each other and an area before the locks. Alternatively, the width of any supports that can be formed is very small and the supports cannot be expected to support the terminal fittings securely. 
     U.S. Pat. No. 6,341,985 discloses a connector with a front holder mounted on the front of the housing. The holder has support walls for the front ends of the terminal fittings and front-stop walls for the cavities. Thus, the walls of the front holder can support the front ends of the terminal fittings. 
     The connector disclosed in U.S. Pat. No. 6,341,985 is a hybrid connector with a group of narrow cavities a group of wide cavities. It is difficult to form supports for supporting the front ends of the terminal fittings in the narrow cavities. However, it is easier to form supports for supporting the front ends of the terminal fittings in the wider cavities. The front holder of the connector shown in U.S. Pat. No. 6,341,985 is a single plate that corresponds to both the narrow cavities and the wide cavities. 
     The front holder of U.S. Pat. No. 6,341,985 becomes very large if the connector has a large number of cavities. However, a large front holder shrinks significantly during resin molding and creates dimensional variations, including displacement of the openings in the holder relative to the cavities. 
     Displacements of openings of the holder relative to the cavities cause portions of the terminal fittings that engage the front holder to be displaced from their proper positions. An electrical connection testing jig and a jig used to withdraw the terminals are inserted into the cavities through the openings of the front holder. However, misalignment of the openings in the holder may prevent proper insertion and maneuvering of the jigs. 
     The present invention was developed in view of the above problem and an object thereof is to prevent displacements of portions of a front holder corresponding to cavities from the cavities. 
     SUMMARY OF THE INVENTION 
     The invention relates to a connector with a housing with cavities and locks that extend along the inner walls of the respective cavities. Terminal fittings are inserted into the corresponding cavities and are locked by the locks. The cavities include at least first and second cavity groups. The cavities in the first cavity group have supports for supporting front ends of the terminal fittings. However, cavities in the second cavity group have no supports. The housing is assembled with a front holder that corresponds only to the second cavity group. The front holder forms front ends of the cavities of the second cavity group and includes supports for supporting the front ends of the terminal fittings inserted into the cavities of the second cavity group. 
     The front holder corresponds to only the second cavity group and thus has a smaller area as compared to a front holder that corresponds to all cavities or more cavities than the second group. Thus, the degree of shrinkage of the front holder during resin molding is reduced and dimensional variations of the front holder are small. As a result, displacements between the cavities of the second cavity group and walls and openings of the front holder are suppressed. 
     The supports in the cavities of the first cavity group for supporting front ends of the terminal fittings take advantage of a difference between the width of the cavities and the width of the locks. 
     Supports are not formed in the cavities of the second cavity group due to a smaller difference between the width of the cavities and the width of the locks as compared to the corresponding difference in the cavities of the first cavity group. 
     The front holder corresponds only to the narrow cavity group, and hence has a smaller area as compared to a front holder that corresponds to all cavities. Thus, shrinkage of the front holder during resin molding is suppressed, and dimensional variations of the front holder are small. As a result, displacements between the smaller cavities and wall portions and openings of the front holder corresponding to the smaller cavities are suppressed. 
     A recess preferably is formed in the front surface of the housing for accommodating the front holder, and the front surface of the front holder is substantially flush with the front surface of the housing when the front holder is accommodated properly in the recess. 
     The front holder forms only part of the front surface of the housing. However, the front of the housing can be substantially flat because the front surfaces of the front holder and the housing are substantially flush when assembled. Thus, the shape of the front surface of the housing is simple. 
     The front holder preferably is mounted to the housing in a mounting direction arranged at an angle to an inserting direction of the terminal fittings into the respective cavities, and preferably a right angle. 
     The mounting of the front holder to the housing may be guided by engaging at least one guide groove with a corresponding guide rib. The guide grooves and the guide ribs preferably are dovetail shaped or undercut. 
     Locking means preferably locks the properly mounted front holder to the housing. 
     The invention also relates to a method of assembling a connector with first and second cavity groups. The method comprises assembling the housing with a front holder that corresponds only to the second cavity group to form front ends of the cavities of the second cavity group and providing supports for supporting the front ends of the terminal fittings in the cavities of the second cavity group. The method then comprises inserting terminal fittings into the corresponding cavities. 
     The front holder preferably is inserted into a recess in the front surface of the housing so that the front surface of the front holder is substantially flush with the front surface of the housing when the front holder is accommodated properly in the recess. 
     The front holder preferably is assembled to the housing in a mounting direction arranged at an angle, and preferably a right angle, to an inserting direction of the terminal fittings into the respective cavities. 
     The assembling step preferably comprises guiding the front holder to the housing by engaging at least one guide groove with a guide rib. The guide groove and the guide rib preferably are dovetailed or undercut. 
     The method may further comprise locking the front holder to the housing when properly mounted. 
     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 partly in section showing a front holder detached from a housing. 
     FIG. 2 is a front view partly in section showing the front holder is assembled with the housing. 
     FIG. 3 is a front view partly in section showing the front holder mounted upside down into the housing. 
     FIG. 4 is a bottom view with the front holder detached from the housing. 
     FIG. 5 is a bottom view of the front holder assembled with the housing. 
     FIG. 6 is a section with the front holder detached from the housing. 
     FIG. 7 is a section with the front holder assembled with the housing. 
     FIG. 8 is a section with the front holder mounted upside down. 
     FIG. 9 is a section with a large terminal fitting in a large cavity. 
     FIG. 10 is a plan view of the front holder. 
     FIG. 11 is a rear view of the front holder. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A connector according to the invention has a housing  10  made e.g. of a synthetic resin. The housing  10  defines a substantially rectangular block, and has left and right wide cavity groups  11 L and one narrow cavity group  11 S between the wide cavity groups  11 L. 
     Each wide cavity group  11 L includes large cavities  12 L arrayed substantially along vertical and transverse directions. Each large cavity  12 L is narrow and long in forward and backward directions and has a substantially rectangular cross-section. Large terminal fittings  20 L are inserted into the large cavities  12 L in an inserting direction ID. A resilient deformable lock  13 L projects forward along the bottom wall of each large cavity  12 L for locking the corresponding large terminal fitting  20 L in the large cavity  12 L. A mold-removing space is defined at the left and right sides before the lock  13 L to accommodate a mold (not shown) for forming the lock  13 L. The large cavity  12 L is wider than the lock  13 L, and left and right supports  15  project from the inner side surfaces of the large cavity  12 L in the area of the lock  13 L and before the lock  13 L (FIG.  9 ). Each support  15  is a narrow rib that extends forward and back parallel with the longitudinal direction of the large cavity  12 L and along the inserting direction ID of the large terminal fitting  20 L. The left and right sides of the front end of the large terminal fitting  20 L are supported from below in the large cavity  12 L by the two supports  15 . 
     A front part of each large terminal fitting  20 L defines a substantially rectangular tube  21 L and a rear part thereof defines a wire crimping portion  22 L to be crimped, bent or folded into connection with a wire  23 . The rectangular tube  21 L of the large terminal fitting  20 L causes the lock  13 L to deform resiliently down during insertion of the large terminal fitting  20 L into the large cavity  12 L. The lock  13 L is restored resiliently when the large terminal fitting  20 L reaches a proper insertion position to engage an engaging portion  24 L of the rectangular tube  21 L from behind. As a result the large terminal fitting  20 L is held so as not to come out. The rectangular tube  21 L of the properly inserted large terminal fitting  20 L is supported by the supports  15  from below or from a lateral side, and preferably substantially normal to the inserting direction ID. 
     The narrow cavity group  11 S includes small cavities  12 S arrayed along vertical and transverse directions. Each small cavity  12 S is narrow and long in forward and backward directions and has a substantially rectangular cross-section. The small cavities  12 S are narrower and shorter than the large cavities  12 L. Additionally, transverse and vertical spacings between the small cavities  12 S are less than the spacings between the large cavities  12 L. A small terminal fitting  20 S is inserted into each small cavity  12 S in the inserting direction ID. A lock  13 S for locking the small terminal fitting  20 S projects forward toward the mating side substantially along the bottom wall of the small cavity  12 S. The lock  13 S is resiliently deformable down in a direction retracted from an insertion path for the small terminal fitting  20 S. 
     A mold-removing space for a mold (not shown) that forms the lock  13 S is defined at the left and right sides of the lock  13 S and before the lock  13 S. The small cavity  12 S is only slightly wider than the lock  13 S. Thus, the small cavity  12 S has no means corresponding to the supports  15  in an area of the large cavity  12 L at the left and right sides of the lock  13 S and before the lock  13 S. Accordingly, front ends of the small terminal fittings  20 S inserted into the small cavities  12 S cannot be supported from below. 
     A recess  16  is formed in an area of the front surface of the housing  10  corresponding to the narrow cavity group  11 S. The recess  16  is open in the front and the bottom surface of the housing  10 , and a front holder  30  can be inserted into the recess  16  in a mounting direction MD, through an opening formed in the bottom surface of the housing  10 . The mounting direction MD of the front holder  30  is substantially normal to the inserting direction ID of the terminal fittings  20 S into the respective cavities  12 S. All of the small cavities  12 S open to the back end surface of the recess  16  that is substantially normal to an inserting direction ID of the small terminal fittings  12 S. Additionally, the front ends of the locks  13 S are close to the back end surface of the recess  16 . 
     Vertically aligned dovetail guide grooves  17  are formed respectively in the inner left and right surfaces of the recess  16  (FIGS. 4,  5 ,  10 ). The guide grooves  17  are transversely symmetrical and extend substantially normal to the inserting direction ID of the small terminal fittings  20 S into the small cavities  12 S. The rear inner surface of each guide groove  17  is substantially continuous and flush with the back end surface of the recess  16 , whereas the front inner surface thereof is oblique to the rear inner surface. The bottom ends of the guide grooves  17  open at the bottom surface of the housing  10 , and guide ribs  31  of the front holder  30  are fit into the guide grooves  17  in the mounting direction MD from below. The front holder  30  is mounted into the recess  16  by engaging the guide grooves  17  and the guide ribs  31 . Further, each guide groove  17  is cut away at an intermediate height position to form a fastening hole  18 . The fastening holes  18  prevent the front holder  30  from downward withdrawal from the recess  16  and open in the front surface of the housing  10  via mold-removing holes  18 H. 
     A widthwise center of the ceiling of the recess  16  is cut away to form a locking hole  19 . The locking hole  19  receives a locking projection  33  of the front holder  30  when the front holder  30  is mounted properly in the recess  16 . 
     A thick substantially rectangular plate-shaped front holder  30  is closely fittable into the recess  16  along a mounting direction MD. The vertical dimension along the mounting direction MD, and the width and thickness of the front holder  30  are substantially equal to corresponding dimensions of the recess  16 . Thus, the front surface of the front holder  30  is substantially flush with the front surface of the housing  10  and the bottom surface of the front holder  30  is flush with the bottom surface of the housing  10  when the front holder  30  is mounted properly in the recess  16 . 
     Transversely symmetrical guide ribs  31  are formed on the left and right surfaces of the front holder  30  and extend substantially straight and vertically along the mounting direction MD. The guide ribs  31  are shaped to fit closely in the guide grooves  17  of the recess  16  so as not to shake to front, back, left or right. The rear and bottom surfaces of the guide ribs  31  are substantially continuous and flush with the rear and bottom surfaces of the guide grooves  17 . A trapezoidal fastening projection  32  is formed on each of the outer surfaces of the guide ribs  31 . The fastening projections  32  fit in the fastening holes  18  of the recess  16  when the front holder  30  is mounted properly in the recess  16  to prevent the front holder  30  from loose downward movements and forward withdrawal from the recess  16 . A locking projection  33  projects up in the mounting direction MD at substantially the widthwise center of the upper surface of the front holder  30 . The rear surface of the locking projection  33  is substantially continuous and flush with the rear surface of the front holder  30 . The locking projection  33  fits into the locking hole  19  of the recess  16  from below when the front holder  30  is mounted properly. 
     Substantially rectangular terminal accommodating portions  34  are formed in the rear surface of the front holder  30  and correspond to the small cavities  12 S. The width and height of the terminal accommodating portions  34  substantially equal the width and height of the small cavities  12 S. Upper, lower, left and right walls of the terminal accommodating portions  34  are substantially flush with the ceiling, bottom, left and right surfaces of the corresponding small cavities  12 S when the front holder  30  is mounted properly in the recess.  16 . The bottom walls of the terminal accommodating portions  34  serve as supports  35  for supporting the front ends of the small terminal fittings  20 S in the small cavities  12 S. The front end of each terminal accommodating portion  34  has a front-stop wall  36  with a tab insertion opening  37  and a jig insertion opening  38 . The outer front surfaces of a plurality of front-stop walls  36  form the flat front surface of the front holder  30 . 
     A front part of each small terminal fitting  20 S is formed into a substantially rectangular tube  21 S and a rear part thereof is formed into a wire crimping portion  22 S for crimped, bent or folded connection with the wire  23 . The rectangular tube  21 S of the small terminal fitting  20 S resiliently deforms the lock  13 S down in the process inserting the small terminal fitting  20 S into the small cavity  12 S. The lock  13 S is restored resiliently and engages an engaging portion  24 S of the rectangular tube  21 S from behind when the small terminal fitting  20 S reaches a proper insertion position. As a result the small terminal fitting  20 S is held so as not to come out. The front end of the properly inserted rectangular tube  21 S is supported from below by the support  35  of the front holder  30  assembled with the housing  10 . 
     The housing  10  is formed with mount-preventing portions  17 S and the front holder  30  is formed with notches  39  to prevent the front holder  30  from being mounted in an improper posture (e.g. turned upside down with respect to the recess  16 ). The mount-preventing portions  17 S are substantially rectangular solid portions at the upper ends of the respective guide grooves  17 , which are the back ends with respect to the mounting direction MD of the front holder  30  into the recess  16 . The bottom surfaces of the mount-preventing portions  17 S are below the ceiling surface of the recess  16 , which is the surface substantially contacted by the upper end of the front holder  30  when the front holder  30  has been mounted properly in the recess  16 . The notches  39  are substantially rectangular recesses on the upper ends of the guide ribs  31  so that the upper ends of the guide ribs  31  are below the upper surface of the front holder  30 . The depth of the notches  39  substantially equals the length of the mount-preventing portions  17 S. Thus, with the front holder  30  properly mounted in the recess  16 , the notches  39  and the mount-preventing portions  17 S nest with almost no clearance therebetween. 
     The front holder  30  is mounted by inserting the upper end of the front holder  30  slightly into the recess  16  from the bottom of the housing  10  so that the upper ends of the guide ribs  31  fit into the bottom ends of the guide grooves  17 . The front holder  30  then is slid up in the mounting direction MD and is held in a proper posture by the engagement of the guide grooves  17  and the guide ribs  31 . The fastening projections  32  project more outward than the guide ribs  31  in the front holder  30 . Thus, the housing  10  tries to undergo a resilient deformation to widen the recess  16  and simultaneously the front holder  30  tries to undergo a resilient deformation to narrow the recess  16 . 
     The mount-preventing portions  17 S and the notches  39  engage and the upper surface of the front holder  30  substantially contacts the ceiling of the recess  16  when the front holder  30  is mounted to a proper position (see FIGS.  2  and  7 ). The fastening projections  32  engage the fastening holes  18  in this state, and prevent the front holder  30  from loose downward movements and withdrawal from the recess  16 . Further, the front holder  30  is prevented from loose forward movements and forward withdrawal from the recess  16  by the engagement of the guide grooves  17  and the guide ribs  31  and by the engagement of the locking projection  33  and the locking hole  19 . In this way, the front holder  30  is locked in its properly mounted state. 
     In this state, the terminal accommodating portions  34  of the front holder  30  face the corresponding small cavities  12 S, and are ready for insertion of the small terminal fittings  20 S. Additionally, the front and bottom surfaces of the front holder  30  are substantially flush with the front and bottom surfaces of the housing  10 . The small terminal fittings  20 S are inserted into the small cavities  12 S after the front holder  30  is mounted, and the front ends of the rectangular tubes  21 S of the small terminal fittings  20 S are inserted into the terminal accommodating portions  34 . Thus, the supporting portions  35  of the front holder  30  support the rectangular tubes  21 S from below (see FIG.  7 ). 
     The front holder  30  could be inverted during an attempted insertion into the recess  16 . In this case, the guide ribs  3  fit into the bottom ends of the guide grooves  17  at an initial stage of the mounting operation and then the front holder  30  continues to be fit into the recess  16 . The upper ends of the guide ribs  31  (bottom ends in the proper posture of the front holder  30 ) contact the mount-preventing portions  17 S from below before the upper surface of the front holder  30  reaches the ceiling of the recess  16  and prevent the front holder  30  from being mounted any further (see FIG.  3 ). In this state, part of the front holder  30  projects from the bottom surface of the housing  10 , and the projecting state can be seen from the front or side of the housing  10 . Hence the improper mounting of the front holder  30  can be detected. The terminal accommodating portions  34  are below the small cavities  12 S in this improperly mounted state. Thus, the rectangular tube  21 S would interfere with the rear surface of the front holder  30  if an attempt were made to insert the small terminal fitting  20 S into the small cavities  12 S. The improper mounting posture can be confirmed visually to prevent the front holder  30  from being mounted in the improper posture. 
     Portions of the housing  10  that have the guide grooves  17  are thinned, and therefore have lower rigidity. However, the mount-preventing portions  17 S at the back ends of the guide grooves  17  improve the rigidity. 
     The front holder  30  corresponds only to the narrow cavity group  11 S. Thus, the front holder  30  has a smaller area than a front holder that corresponds to both the wide cavity groups  11 L and the narrow cavity group  11 S. Accordingly, the degree of shrinkage of the front holder  30  during resin molding is suppressed, and dimensional variations of the front holder  30  are smaller. As a result, displacements between the small cavities  12 S and the walls and openings of the front holder  30  corresponding to the small cavities  12 S are suppressed. 
     The front holder  30  forms only part of the front surface of the housing  10 . Additionally, the front surfaces of the front holder  30  and the housing  10  are substantially flush with each other. Thus, the front surface of the housing  10  can be flat, and the shape of the front surface of the housing  10  is simple. 
     The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments also are embraced by the technical scope of the present invention as defined by the claims. Beside the following embodiments, various changes can be made without departing from the scope and spirit of the present invention as defined by the claims. 
     The small cavities of the narrow cavity group are gathered at one location in one housing in the foregoing embodiment. However, the invention also is applicable to connectors with a plurality of narrow cavity groups located in one housing. 
     The narrow cavity group is in the widthwise center of the housing in the foregoing embodiment. However, the invention also is applicable to connectors where the narrow cavity group is more towards either the left or right side. 
     Although the front holder is mounted in the direction MD substantially normal to the inserting direction of the terminal fittings in the foregoing embodiment, the front holder may be mounted in a direction substantially parallel with the inserting direction ID of the terminal fittings.