Abstract:
A connector for electrical terminals includes a housing that has a plurality of cavities, a plurality of respective resiliently deformable locking members, and a plurality of respective terminals. Each terminal is inserted in a respective cavity and has (a) a partially inserted position in which the terminal bears on the respective locking member to deform the locking member so that the locking member is raised with respect to a peripheral surface of the housing, and (b) a fully inserted position in which the locking member snap-fits to the terminal thereby locking the terminal in said cavity. The connector further includes a bus bar holder having a sleeve which accommodates a plurality of bus bar tab pieces. The sleeve is push-fitted over the peripheral surface of the housing to install the bus bar holder to the housing and to contact the tab pieces to the terminals, whereby the terminals are electrically connected to each other. Each locking member has an end surface portion which is adapted so that when, on push-fitting of the sleeve, a terminal is in the partially inserted position with the respective locking member raised with respect to the peripheral surface of the housing, the sleeve bears on the end surface portion to prevent installation of the bus bar holder.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a connector, particularly a connector for use in the wiring of a vehicle such as an automobile. 
     2. Description of Related Art 
     A connector disclosed in Japanese Patent Application Laid-Open No. 9-213436 is described below. The connector has a housing into which a plurality of terminals are inserted from a rear portion thereof and a bus bar holder in which a holding member holds a plurality of bus bars each of which has a tab piece projecting from a side edge of a belt-shaped carrier. The bus bar holder is inserted into an opening at the front surface of the housing to connect the tab pieces with the terminals. In this manner, the terminal fittings are electrically connected to each other. 
     It is also known to lock the terminals into a position in the housing with a plurality of respective locking lances. Theses lances may project outwardly from the housing if the terminals are not fully inserted. 
     The tab pieces project from the holding member of the bus bar holder and are externally exposed. Therefore, when the bus bar holder is packed in a bag or a box for delivery, or when it is installed to the housing, other bus bar holders may catch on the tab pieces. Thus, there is a risk that the tab pieces can be deformed or damaged. 
     To prevent such risk, it is known to use a bus bar holder having a protective cylindrical sleeve which accommodates the tab pieces. This construction has an advantage of helping to prevent the tab pieces from being deformed or broken. 
     Also, with this arrangement the bus bar holder is capable of detecting incomplete insertion of the terminals in the connector housing. When the terminals are fully inserted into the connector housing, the sleeve can be installed onto the housing without interfering with the locking members which hold the terminals in place. On the other hand, when any of terminals is not properly inserted into the connector housing, the respective locking member projects from the peripheral surface of the housing and collides with the end surface of the sleeve on installation. That is, the proper or improper insertion of the terminals can be detected by whether the sleeve interferes with the locking members. 
     However, when a projecting lance collides with the cylindrical sleeve, the lance may flex excessively, possibly breaking or damaging the lance. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to prevent a locking member or lance from flexing excessively when a bus bar holder is installed on a connector housing and the respective terminal is not properly inserted. 
     According to the present invention there is provided a connector for electrical terminals. The connector has a housing with a peripheral surface, a plurality of cavities, a plurality of resiliently deformable locking members, and a plurality of terminals. Each terminal is inserted in a respective cavity and has (a) a partially inserted position in which the terminal bears on the respective locking member to deform the locking member so that the locking member is raised with respect to a peripheral surface of the housing, and (b) a fully inserted position in which the locking member snap-fits to the terminal thereby locking the terminal in the cavity. 
     The connector also has at least one bus bar holder with a sleeve and a plurality of bus bar tab pieces which are accommodated in the sleeve. The sleeve is push-fitted over the peripheral surface of the housing to install said bus bar holder to the housing and to contact the said tab pieces to the terminals. In this way the terminals are electrically connected to each other. 
     Each locking member has an end surface portion which is inclined with respect to the push-fit direction of the sleeve. Therefore, when, on push-fitting of the sleeve, a terminal is in its partially inserted position with the respective locking member raised with respect to peripheral surface, the sleeve bears on the respective first end surface portion to urge the locking member toward the terminal. This prevents excess deformation of the locking member from occurring. 
     Each of the locking member may also have a second end surface portion which faces the first end surface portion and, with respect to the first end surface portion, is oppositely inclined with respect to the push-fit direction of the sleeve. In this way, when, on push-fitting of the sleeve, each terminal is in its partially inserted position with the respective locking member raised with respect to the peripheral surface, the sleeve also bears on the second surface portion to urge the locking member away from the terminal. 
     The first and second end surface portions may, for example, define a V-shaped recess in the respective locking members. 
     When the sleeve of the bus bar holder contacts both the first and the second end surface portions of a locking member, the locking member experiences opposing and balance forces on its end surface portions. These forces prevent it from being displaced either away from or toward the terminal. Thus the installation of the bus bar holder on the housing is prevented. That is, even though the bus bar holder is urged strongly against the locking member, the locking member is prevented from being forcibly displaced in a direction which would remove its elastic deformation. Therefore, the locking member is prevented from being pressed against the terminal with an excessive force and possibly being damaged. 
     Preferably, the angle of inclination of the first end surface portion with respect to the push-fit direction of the sleeve is smaller than the angle of inclination of the second end surface portion with respect to the push-fit direction when the sleeve bears on both the first and second end surface portions. 
     With this arrangement, the force applied to a locking member by the sleeve in the direction which would remove its elastic deformation (i.e. toward the terminal) is greater than the force applied in the direction which would increase its elastic deformation (i.e. away from the terminal). Accordingly, it is possible to avoid excess flexing and deformation of the locking member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of this invention will be described in detail by way of non-limitative example with reference to the following drawings, in which: 
     FIG. 1 is a perspective view of a housing of a connector according to the invention; 
     FIG. 2 is a partly cut-away perspective view of bus bar holders that engage the housing, seal member and seal holder of FIG. 1; 
     FIG. 3 is a perspective view of a cap that covers the housing of FIG.  1  and the bus bar holders of FIG. 2; 
     FIG. 4 is a sectional view of the connector in an engagement state on plane I—I of FIG. 1, plane II—II of FIG.  2  and plane III—III of FIG. 3; 
     FIG. 5 is a sectional view on plane I—I of FIG. 1, showing a sealing member and a seal holder installed on the housing; 
     FIG. 6 is a sectional view on plane II—II of FIG. 2; 
     FIG. 7 is a sectional view on plane III—III of FIG. 3; 
     FIG. 8 is an enlargement of a part of the sectional view of FIG. 4, showing a terminal fully inserted into the housing; 
     FIG. 9 is the same view as FIG. 8 except that the terminal is partially inserted into the housing; 
     FIG. 10 is the same view as FIG. 9 except that a locking lance of the housing is further deformed by a sleeve of the bus bar holder; 
     FIG. 11 is a partly cut-away plan view of the housing; 
     FIG. 12 is a rear view of the sealing member; and 
     FIG. 13 is a rear view of the seal holder. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A connector embodying the present invention is described in conjunction with FIGS. 1 to  13 . The connector electrically connects a plurality of terminals  20  in a predetermined connection pattern with a bus bar  55  and includes a housing  10 , a plurality of the terminals  20 , a sealing member  30 , a seal holder  40 , two bus bar units  50 , and a cap  60 . 
     The housing  10  is made of a synthetic resinous material. As shown in FIGS. 1 and 5, the housing  10  may have cavities  11  arranged in upper and lower rows and extending through the housing  10  in a front-to-rear direction. In each of the upper and lower rows, the cavities  11  may be arranged widthwise at regular intervals. The front half regions of the upper-row cavities  11  and the lower-row cavities  11  are open at the upper and lower surfaces of the housing  10 , respectively. In each open portion, locking members, such as locking lances  12 , project forward in a cantilever manner. Between the upper and lower rows of the cavities  11  there is formed a wide recess  13  for allowing the peripheral walls of the bus bar units  50 , as described below, to penetrate. An upper surface wall and a lower surface wall of the recess  13  are partly cut away to allow communication with the cavities  11 . 
     The locking lances  12  retain and prevent the removal of the terminals  20  inserted into the cavities  11 . In cooperation with a cylindrical portion  53  of the bus bar unit  50  shown in FIGS. 8-10, locking the lances are also used for detecting the degree of insertion of the terminals  20 . The locking lances  12  can be outwardly elastically displaced relative to an outer surface  10 A of the housing  10 . As shown in FIG. 8, before a terminal  20  is inserted into a cavity  11  and after the terminal  20  is fully inserted therein, a corresponding locking lance  12  is undeformed, and an outer surface  12 A of the locking lance  12  is flush with the outer surface  10 A of the housing  10 . In this state, when the terminals  20  are fully inserted, a removal prevention projection  12 B formed at a front end of each locking lance  12  is engaged in a locking hole  24  of the terminal  20 , thus preventing removal of each terminal  20 . However, as shown in FIG. 9, when any of the terminals  20  are not fully inserted, the removal prevention projection  12 B interferes with the outer surface of a mating portion  21  of the terminal  20 . As a result, as described in FIG. 10, the locking lance  12  is elastically displaced such that its outer surface  12 A is located outwardly from the surface  10 A of the housing  10 . Therefore, when a bus bar unit  50  is installed on the housing  10 , the cylindrical portion  53  of the bus bar unit  50  collides with the front end of the locking lance  12 . This prevents the bus bar unit  50  from being installed on the housing  10 . 
     At the front-end surface of each locking lance  12 , there is formed an excess flexure prevention surface  12 C that prevents the locking lance  12  from flexing excessively beyond the limit of its elasticity, when the cylindrical portion  53  collides with the front end of the locking lance  12 . At the front-end surface of each locking lance  12 , there is also formed a balancing surface  12 D inclining in a direction opposite to the direction of inclination of the excess-flexure prevention surface  12 C. For example, in a side view, the front-end surface of the locking lance  12  may be recessed in the shape of a “V”, as shown in FIGS. 8-10. The inward side, i.e., the terminal side, of the front-end surface of the locking lance  12  is the excess-flexure prevention surface  12 C and the outer side of the front-end surface is the balancing surface  12 D. 
     While the surfaces  12 C and  12 D form a “V” shape in FIGS. 8-10, it will be appreciated that other shapes are possible. For example, the surfaces  12 C and  12 D may form a curved “U” shape, rather than being linear surfaces that form a “V”. Additionally, rather than two linear surfaces, one or more of the surfaces may be curved, and/or more than two surfaces may be provided at the end of each locking lance  12 . 
     While the locking lance  12  is elastically displaced within its elastic limit, an end surface of the cylindrical portion  53  collides with the excess-flexure prevention surface  12 C when each bus bar unit  50  is installed on the housing  10 . The excess-flexure prevention surface  12 C is so inclined that the excess-flexure prevention surface  12 C stops and reduces excess elastic deformation of the locking lance  12 , as best shown in FIG.  10 . 
     While the locking lance  12  is elastically displaced within its elastic limit, the cylindrical portion  53  is also capable of colliding with the balancing surface  12 D, when each bus bar unit  50  is installed on the housing  10 . The balancing surface  12 D is inclined so that the locking lance  12  is then urged in a direction in which the elastic displacement of the locking lance  12  increases (upward in FIGS. 8 to  10 ). Ultimately the cylindrical portion  53  contacts both the excess-flexure prevention surface  12 C and the balancing surface  12 D, as shown in FIG.  10 . Comparing the relative inclinations of the excess-flexure prevention surface  12 C and the balancing surface  12 D when both surfaces are in contact with the cylindrical portion  53 , as shown in FIG. 10, the acute angle α between the direction of insertion of the cylindrical portion  53  and the excess-flexure prevention surface  12 C is smaller than the angle β between the insertion direction the cylindrical portion  53  and the balancing surface  12 D. 
     Each terminal  20  is made of a metal plate material punched into a predetermined configuration. As shown in FIG. 1, the front half part of the terminals  20  may be formed as a square pillar-shaped mating portion  21  that is open forward and rearward. The rear half of the terminals  20  is formed as an electric wire connection portion  22  that may be crimped to the core of an electric wire  25 . 
     As shown in FIG. 4, a resilient contact piece  23  that contacts a connection piece  57  of a bus bar  55  is formed inside the mating portion  21 . A locking hole  24  which the locking lance  12  of the housing  10  engages is formed on a peripheral wall of the mating portion  21 . The terminals  20  are inserted into the cavities  11  of the housing  10  by passing through the sealing member  30  and the seal holder  40  at the rear of the housing  10 . Immediately before the terminals  20  reach the fully inserted position, the locking lances  12  interfere with the peripheral surface of the mating portions  21 . Therefore, the locking lances  12  flex elastically outward from the housing  10 . When the terminals  20  reach the fully inserted position, the locking lances  12  are elastically restored to the original state and are engaged in the locking holes  24 , thus preventing the terminals  20  from being removed from the cavities  11 . The orientation of the terminals in the upper row of cavities  11  may be reversed relative to that of the terminals in the lower cavity row. 
     The sealing member  30  is made of rubber, oval-shaped, and thick. As shown in FIG. 5, the sealing member  30  is installed on the housing  10  and is sandwiched between the rear end surface of the housing  10  and the front end surface of the seal holder  40 . The construction of the sealing member  30  with the housing  10  and the seal holder  40  is described in more detailed below with reference to FIGS. 11-13. A plurality of sealing holes  31  opened through the sealing member  30  is formed coincident with the cavities  11  of the housing  10 . Each sealing hole  31  may be circular, for example. A lip portions  31 A may have a corrugated shape that includes, for example, three convexities. The convexities are circumferentially formed on the inner peripheral surface of each sealing hole  31 . The inner diameter of the lip portion  31 A is smaller than the outer diameter of the coating of the wire  25 . When the wire  25  is in the sealing hole  31 , the lip portion  31  A contacts the peripheral surface of the wire  25  elastically, thus sealing around the wire  25 . Furthermore, as shown in FIG. 12, the sealing member  30  includes fit-in holes  32  and  33  through which holding projections  14  and deformation prevention projections  15  pass, respectively. 
     As shown in FIG. 11, the holding projections  14  include a base portion  14 A and a locking portion  14 B. As the base portions  14 A pass through the fit-in holes  32 , the locking portions  14 B enter removal prevention holes  42  and engage with stepped receiving portions  42 A, preventing the housing  10 , the sealing member  30  and the seal holder  40  from being separated. The deformation prevention projections  15  also pass through the fit-in holes  33  and enter deformation prevention holes  43 . The deformation prevention projections  15  prevent deformation of the sealing member  30 . 
     The inner diameters of the fit-in holes  32  and  33  are smaller than the holding projections  14  and deformation prevention projections  15 , respectively. Thus, when the holding projections  14  and the deformation prevention projections  15  pass the fit in holes  32  and  33 , respectively, the holding projections  14  and the deformation prevention projections  15  contact fit-in holes  32  and  33  with elasticity, sealing around the holding projections  14  and deformation prevention projections  15 . 
     The peripheral edge of the sealing member  30  is formed as a corrugated sealing edge. A lip portion  34  has, for example, three convexities approximately semi-circular in section and extending circumferentially around the sealing member  30 . The lip portion  34  contacts the inner peripheral surface of the cap  60  elastically, thus sealing between the sealing member  30  and the cap  60  as shown in FIG.  4 . 
     The seal holder  40  is made of a relatively rigid synthetic resin material. Similarly to the sealing member  30 , the seal holder  40  may be oval-shaped and thick as shown in FIG.  1 . The lip portion  34  formed on the periphery of the sealing member  30  is slightly larger than the periphery of the seal holder  40 . A plurality of terminal insertion openings  41  extend through the seal holder  40  in correspondence to the cavities  11  and the sealing holes  31 . Each terminal  20  is inserted into a respective cavity  11  through a respective terminal insertion opening  41 . 
     As shown in FIG.  1  and FIG. 4, locking projections  44  are formed at each end of upper and lower surfaces of the seal holder  40 . The locking projections  44  engage the cap  60 , thus hindering the cap  60  from being easily removed from the housing  10 , the sealing member  30 , and the seal holder  40 . An index projection  45  is formed in each circular arc-shaped region located at right and left ends of the peripheral surface of the seal holder  40 . Each of the index projections  45  is formed such that the inward side thereof is on a level higher than that of the outward side thereof. The index projections  45  serve as an index for checking the upper and lower sides of the housing  10  when the terminal fixtures  20  are inserted into the cavities  11  and when the housing  10  is inserted into the cap  60 . 
     As shown in FIGS. 2,  4  and  6  each bus bar unit  50  is composed of a holding member  51  made of a relatively rigid synthetic resin material and a metal bus bar  55  that is integrated with the holding member  51  by insert molding. The holding member  51  has a wide sheet-shaped holding portion  52  and a flat cylindrical portion  53  projecting from the sheet-shaped holding portion  52 . The bus bar  55  includes a plurality of connection pieces  57  projecting in parallel with each other, each in the shape of a cantilever, from an edge of a belt-shaped carrier  56 . The bus bar  55  is held with the carrier  56  disposed along the sheet-shaped holding portion  52  and with connection pieces  57  facing the cylindrical portion  53 . Punched holes  54  are formed on the sheet-shaped holding portion  52  in correspondence to the gap between adjacent connection pieces  57  projecting from the carrier  56 . In the process of producing the bus bar units  50 , a portion of the carrier  56  facing each punched hole  54  is punched with a punch and die in correspondence to a predetermined connection pattern. As a result, the carrier  56  is divided (not shown) into a plurality of bus bars  55 . One bus bar  55  has at least three connection pieces  57 . A plurality of terminals  20  are connected by each bus bar  55  through the connection pieces  57 . 
     Each bus bar unit  50  is installed on the housing  10  in a direction forward therefrom such that the cylindrical portion  53  covers the upper-row cavities  11  or the lower-row cavities  11 . When each bus bar unit  50  has been installed on the housing  10 , the connection pieces  57  are connected with the terminals  20 . Connection patterns can be discriminated from each other by, for example, changing the color of the holding member  51  of the bus bar unit  50 . The upper part of the holding member  51  and the lower part thereof are not symmetrical. Thus, the correct bus bar unit  50  can be installed on the housing  10  in a correct direction, and a group of the terminals  20  can be connected in a correct pattern by checking colors and directions of the holding members  51 . 
     As shown in FIG. 2, guide grooves  58  extend longitudinally and are formed at each of right and left widthwise edges of the cylindrical portion  53 . As shown in FIG. 1, front and rear locking projections  17  and  18  correspond positionally to the guide groove  58  and are formed on the housing  10 . Each bus bar unit  50  is brought to a temporary locking position with the locking projections  18  locked in the guide grooves  58 . In this state, the bus bar unit  50  is held at a temporary locking position. In this state, each connection piece  57  is placed at a retracted position at which the connection piece  57  is not in contact with each terminal  20 , thus preventing generation of resistance at the time of insertion of the terminals  20 . The bus bar unit  50  is then brought to the final installation position by locking the front and rear ends of the guide groove  58  by the locking projections  17  and  18 , respectively. In this state, the front and rear ends of the guide groove  58  sandwich the locking projections  17  and  18 . 
     Each bus bar unit  50  can be used to detect the inserted state of the terminals  20 . As shown in FIG. 8, the cylindrical portion  53  is installed on the housing  10  by sliding it along the surface  10 A of the housing  10 . An inclined surface  53 A is formed on the front-end surface of the cylindrical portion  53  such that the outer side thereof extends further than the inner side (housing side) thereof. The inner-side edge of the inclined surface  53 A is a prevention edge  53 B that contacts the excess-flexure prevention surface  12 C of the locking lances  12 . The outer-side edge of the inclined surface  53 A is a balancing edge  53 C which contacts the balancing surface  12 D of the locking lances  12 . When the bus bar unit  50  has been fully inserted to the housing  10 , the front end of the cylindrical portion  53  covers the outer surface of the front portion of the locking lances  12 . 
     A description of the cap  60  is given with reference to FIGS. 3 and 7. The cap  60  is made of a relatively rigid synthetic resin material. As shown in FIG. 3, the cap  60  is oval-shaped in a front view and has a closed bottom. Locking holes  61  to which the locking projections  44  of the seal holder  40 , shown in FIG. 1, lock are formed at an edge of an opening of the cap  60 . The cap  60  is locked in the installed state by the engagement between the locking projections  44  and the locking holes  61 . Relief portions  62  project outwardly and are formed on the edge of the opening of the cap  60  to prevent the cap  60  from interfering with the index projections  45  of the seal holder  40 . As shown in FIG. 7, a region of the inner peripheral surface of the cap  60  near the edge of the opening is formed as a sealing surface  63  with which the lip portion  34  formed on the peripheral edge of the sealing member  30  contacts elastically (see FIG.  4 ). 
     The connector assembly procedure is as follows: 
     Initially, the sealing member  30  is sandwiched between the seal holder  40  and the housing  10 . Then, the projections  14  formed on the housing  10  are passed through the sealing member  30 , and locking portions  14 B of the projections  14  are locked to the seal holder  40 . This locks the seal member  30  to the housing  10 , and the removal of the seal holder  40  is prevented. Then, terminals  20  are inserted through the terminal insertion openings  41  and the sealing holes  31  into respective cavities  11 . Thereafter, each bus bar unit  50  is installed at a temporary locking position on the housing  10 , and the bus bar unit  50  is placed on an assembling apparatus (not shown). Then, each bus bar unit  50  is pressed to a normal installation portion from the temporary locking position. As a result, the terminals  20  are connected in a predetermined pattern. When the bus bar units  50  are in the normal installing position, the cap  60  is installed on the housing  10  in such a manner that the cap  60  covers the housing  10  and the bus bar unit  50  as shown in FIG.  4 . 
     The lip portions  34  formed on the periphery of the sealing member  30  prevent water from penetrating into the cap  60  between the inner periphery of the cap  60  and the periphery of the sealing member  30 . Further, the lip portions  31 A of the sealing holes  31  contact the periphery of the wires  25  closely, the inner periphery of each fit-in hole  32  contacts the periphery of the corresponding holding projection  14 , and the inner periphery of the fit-in hole  33  contacts the periphery of the deformation prevention projection  15 . Therefore, water can be prevented from penetrating into the sealing member  30  from outside. 
     On installation of each bus bar unit  50  on the housing  10  when all the terminals  20  are fully inserted into their respective cavities  11 , each locking lance  12  is undeformed so that its outer surface  12 A is flush with the outer surface  10 A of the housing  10 . Accordingly, when the cylindrical portion  53  slides over the outer surface  10 A of the housing  10  during bus bar unit installation, the cylindrical portion  53  does not interfere with the locking lances  12 . Thus, each bus bar unit  50  can be installed on the housing securely. When each bus bar unit  50  has been installed on the housing  10  in the normal state, the cylindrical portion  53  faces the locking lances  12  in such a manner that the inner surface of the cylindrical portion  53  holds downward on the outer surfaces  12 A of the locking lances  12 . Thus, the locking lances  12  are prevented from being elastically displaced in a direction which would move them away from the terminals  20  (see FIG.  8 ). 
     On the other hand, if there is any terminal  20  inserted into the cavity  11  incompletely, the removal prevention projection  12 B interferes with the outer surface of the mating portion  21  of the terminal  20 . Thus, the locking lance  12  is elastically displaced outward and projects outward from the outer surface  10 A of the housing  10 . During installation of each bus bar unit  50  on the housing  10 , the inclined surface  53 A that is formed at the front end of the cylindrical portion  53  then contacts the outer-side edge of the locking lance  12 . As a result, the installation operator notices that the installation resistance is suddenly increased. In this manner, the operator can detect that a terminal is in the incomplete insertion state (see FIG.  9 ). 
     The operator suspends the installation operation with the connector in the state shown in FIG.  9  and resumes the installation operation after inserting the terminal  20  into the normal position of the cavity  11 . However, it may happen that the operator continues to perform the installing operation without noticing a sudden increase in installation resistance. The locking lance  12  shown in FIG. 9 is then displaced upward by a force acting in the bus bar unit installation direction, the balancing edge  53 C of the cylindrical portion  53  contacting and transmitting the force to the balancing inclined surface  12 D. If the locking lance  12  were to flex upward further and exceed the limit of its elasticity, it would not be restorable to the undeformed state shown in FIG.  8 . However, this is prevented because when the locking lance  12  flexes further, to a position still within its elastic limit, the prevention edge  53 B of the cylindrical portion  53  contacts the excess-flexure prevention surface  12 C (see FIG.  10 ). The excess-flexure prevention surface  12 C has an inclination such that the locking lance  12  is urged in the opposite (elasticity-restoring) direction by the collision force of the cylindrical portion  53  applied to the excess-flexure prevention surface  12 C. Thus, the locking lance  12  is prevented from being elastically displaced further. 
     As described above, as a mechanism to prevent the locking lances  12  from flexing excessively beyond the limit of their elasticity, the cylindrical portion  53  is pressed against the excess-flexure prevention surface  12 C. Thus, it is also unnecessary to provide the housing  10  with a wall for preventing excess deformation of the locking lance  12 , which makes it possible to reduce the width of the housing  10 . 
     When the cylindrical portion  53  of each bus bar unit  50  contacts both the excess-flexure prevention surface  12 C and the balancing surface  12 D, as shown in FIG. 10, the locking lances  12  are prevented from being displaced in either direction. Thus installation of the bus bar unit  50  on the housing  10  is prevented. That is, even if the bus bar unit  50  is pressed strongly against the lances  12 , the lances  12  are prevented from being forcibly displaced in the elasticity-restoring direction. In particular, when the cylindrical portion  53  contacts the balancing surfaces  12 D, the locking lances  12  are spaced from the terminals  20 . Therefore, even though the locking lance  12  may be displaced slightly in the elasticity-restoring direction, there is no possibility that the locking lance  12  is urged excessively against the terminals  20 . 
     The acute angle α formed between the insertion direction of the cylindrical portion  53  and the excess-flexure prevention surface  12 C is smaller than the angle β which formed between the insertion direction and the balancing surface  12 D. Thus, when a force acting in the installation direction is initially applied to the locking lances  12  by the cylindrical portion  53 , the resultant force that is applied to the locking lances  12  in the downward (elasticity-restoring) direction (i.e., torward the cavity) is greater than the resultant force that is applied in the upward (increased elastic displacement) direction (i.e., away from the cavity). Accordingly, it is possible to prevent excess deformation of the locking lances  12 . 
     The inclined surface  53 A of the cylindrical portion  53  may be inclined with respect to the bus bar unit-installation direction, as shown in the drawings. Therefore, even if the locking lances  12  may be slightly raised with respect to the outer surface  10 A of the housing  10  when the terminals  20  are fully inserted, the lances  12  are not snagged by prevention edge  53 B of the cylindrical portion  53  during installation of each bus bar unit  50  into the housing  10 . 
     The present invention is not limited to the embodiments described, but may be varied, for example, as described below. 
     (1) In the above description, the front end surface of the cylindrical portion  53  of the bus bar unit  50  is angled and the edges of the surface contact the excess-flexure prevention surface  12 C and the balancing surface  12 D. However, within the present invention, the front end surface of the cylindrical portion  53  may be V-shaped so that the end surface corresponds to and contacts the excess-flexure prevention surface  12 C and the balancing surface  12 D. 
     (2) In the above description, the acute angle α between the insertion direction of the cylindrical portion  53  and the excess-flexure prevention inclined surface  12 C is smaller than the angle β between the insertion direction and the balancing inclined surface  12 D. However, within the present invention, although less desirably, angle α may be larger than angle β or angle α may be equal to angle β. 
     (3) In the above description, the balancing surface  12 D is in addition to the excess-flexure prevention surface. However, within the present invention, it is possible to form only the excess-flexure prevention inclined surface. 
     (4) In the above description, the end surface of the cylindrical portion  53  is angled relative to the insertion direction of the cylindrical portion. However, according to the present invention, the end surface of the cylindrical portion  53  may be perpendicular to the insertion direction, or may be angled in the opposite direction. 
     (5) In the above description, the cylindrical portion  53  initially contacts the outer-side edge of the locking lance  12  when a terminal is partially inserted. However, within the present invention, the cylindrical portion  53  may contact an inclined surface of the locking lance  12  initially. In this case, the locking lance  12  first contacts the balancing surface  12 C, and thereafter the excess-flexure prevention surface  12 D after slight displacement of the locking lance  12 . Alternatively the cylindrical portion  53  may contact both inclined surfaces. 
     (6) In the above description, a connector of waterproof type has been described. However, the present invention is also applicable to connectors of non waterproof type. 
     Although the invention has been described above in relation to particular embodiments, many variations are possible within the spirit and scope of the invention herein described, as will be appreciated by those who are skilled in the art, once given this disclosure.