Abstract:
An electric connection box, for use in vehicles etc., has vertical parallel bus bars which permit a variety of bus bar circuits to be easily made. The electric connection box has upper and lower casing parts containing the vertical bus bars which may be identical, each having a sheet-form bar body, a plurality of tab terminals, and a plurality of pressure contact blades. At least some of the tab terminals project at regular intervals on one side of the bus bar body and at least some of the pressure contact blades project on the opposite side. To connect the bus bars electrically to form a bus bar circuit, wires are brought into pressure contact with the appropriate pressure contact blades.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connection box containing bus bars, suitable for use, for example, in vehicles, such as automobiles. The invention also relates to a method of making such a box. 
     2. Description of Related Art 
     An electrical connection box described in U.S. Pat. No. 5,624,280, corresponding to Japanese Laid-Open Patent Application No. 7-135717, is a branched connection box, having an upper case part and a lower case part that are connected to each other, and a plurality of parallel vertical bus bars accommodated in the cases. These vertical bus bars are equipped with a plurality of terminals (tab terminals) projecting upwardly and downwardly in the box. The tab terminals project through the case into connector-receiving recesses provided on each case part, for connection with the terminals of connectors to be fitted to the box. 
     When using such electrical connection boxes for different vehicle types, circuit connections of the bus bars are required to be varied according to the respective circuit arrangements of the vehicles. 
     However, when making the bus bar connections in this type of boxes, the wires have to be connected to the respective tab terminals projecting from the terminal holes of the connectors. For this reason, there is a necessity to fix to the tip of the wire a connection terminal that can be engaged with the tab terminal. This requires complicated work in connection of the wires, and uses a large number of parts. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an electric connection box having bus bars, which allows easy adaptation and choice of the bus bar circuit connections. 
     According to the invention, there is provided an electrical connection box having connectable upper and lower casing parts defining an interior space when connected. A plurality of bus bars are arranged within the interior space in a side-by-side array with respective main body portions of a sheet form arranged vertically and parallel to each other. The upper casing part has connector regions to receive exterior connector members in use. Each bus bar has a plurality of tab terminals projecting upwardly away from the bus bar main body portion on the upper side thereof and protruding into the connector regions. At least one pressure contact blade projects downwardly from the bus bar main body portion for making pressure contact with an electrical wire. 
     Preferably, the respective pressure contact blades of the bus bars are arranged in at least one row orthogonal to the direction of the bus bar main body portions, so that in use an electrical wire making contact with the pressure contact blades can extend linearly in the orthogonal direction. 
     In another aspect, the invention provides a method of making an electrical connection box, including the steps of: 
     providing connectable upper and lower casing parts defining when connected an interior space, the upper casing part having connector regions to receive exterior connector members in use, 
     inserting into respective predetermined holding locations of one of the casing parts a plurality of bus bars which each have a main body portion of sheet form, the main body portions being arranged vertically and parallel to each other in their inserted locations, the bus bars each having a plurality of tab terminals on the upper side of the bus bar main body portion which protrude into the connector regions in the inserted locations of the bus bars and at least one pressure contact blade projecting downwardly from the bus bar main body portion, 
     before or after the inserting step, establishing electrical connections between the bus bars in a predetermined manner by electrical wires making pressure contact with the pressure contact blades, and 
     connecting the upper and lower casing parts together so as to secure the bus bars and wires in the interior space. 
     In this specification, including the claims, the directional terms “upper”, “lower”, “vertically” etc. are used relatively to each other for convenience of explanation and definition and refer to the orientations shown in the figures. However, the connection box of the invention can be assembled and used in any orientation appropriate to a particular assembly process or use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described by way of non-limitative example with reference to the accompanying drawings, in which: 
     FIG. 1 is an exploded top perspective view of an electrical connection box of one embodiment of the invention; 
     FIG. 2 is an exploded button perspective view of the electrical connection box of FIG. 1; 
     FIG. 3 is a sectional view on the line A—A in FIG. 1; 
     FIG. 4 is the same sectional view as FIG. 3 showing the assembled state of the box; 
     FIG. 5 is a bottom perspective view of a vertical bus bar of the same embodiment; 
     FIG. 6 is a perspective view of an example of modification of the bus bar circuits; 
     FIG. 7 is a front view of a vertical bus bar of another embodiment of the invention; and 
     FIG. 8 is a front view of a vertical bus bar of yet another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     One embodiment of the present invention is described in detail below with reference to FIGS. 1 to  6 . 
     As shown in FIGS. 1 and 2, the electrical connection box  11  is constituted by an upper casing part, here called upper case  12 , a lower casing part, here called lower case  13 , and an array  14  of bus bars. 
     The upper case  12  and the lower case  13  are respectively made, each in one piece, of synthetic resin, and are mutually engageable to connect them together. In detail, on each side of the upper case  12 , there are formed first engaging parts  12   a , and on the inside of the lower case  13  there are formed complementary second engaging parts  13   a  which connect in snap-fit manner with the first engaging parts  12   a.    
     The array  14  of bus bars is constituted by ten vertical bus bars  15   a - 15   j , each formed of a metal sheet as one piece. The respective bus bars  15   a - 15   j  in this embodiment all have the same shape and configuration, and are formed by punching and bending metal sheet. Each bus bar  15   a - 15   j  has a plate-form or sheet-form planar main bus bar body  21 , a plurality of tab terminals  22 , and a plurality of pressure contact blades  23  which are coplanar with the body  21 . The tab terminals  22  project on one side of the bus bar body  21  and are spaced at predetermined regular intervals. The pressure contact blades  23  project on the opposite side, at equal intervals, at locations horizontally offset from the tab terminals  22 . The tab terminals  22  and pressure contact blades  23  thus alternate along the bus bar body  21 . 
     On the same side as the pressure contact blades  23  the bus bar body  21  has a plurality of projections  21   a , at predetermined intervals, whose lower edges are flush with the bottom face of the upper case  12  when the bus bars  15   a - 15   j  are completely inserted in the upper case  12 . 
     On the top face of the upper case  12 , there are formed a plurality of connector housings  24 , in the form of recesses defined by upstanding walls. These receive exterior connectors in use. Also, as shown in FIGS. 2 and 3, on the bottom face side of the upper case  12 , there are bus bar receiving grooves  25  defined by separating walls  25   a , which accommodate the bus bars  15   a - 15   j  at equal spacings and in parallel. 
     As shown in FIG. 1, on the upper face of the lower case  13 , corresponding to the grooves  25  of the upper case there are bus bar accommodating recesses or grooves  26  defined by separating walls  26   a . Additionally, on the upper face of the lower case  13 , there are a plurality of ribs  27  higher than the walls  26   a  and linearly extending orthogonally to the grooves  26  at predetermined intervals, at the positions corresponding to the projections  21   a  of the bus bars  15   a - 15   j  when installed. 
     In the electrical connection box  11 , each bus bar  15   a - 15   j  is accommodated upright in a groove  25  with the tab terminals  22  directed upwardly, as shown in FIG. 1 to FIG.  4 . As shown in FIG. 3, in the bottom wall of each connector housing  24  there are a plurality of through holes  24   a , through which the tab terminals  22  are thrust, while the pressure contact blades  23  of the bus bars are arranged in rows in the direction orthogonal to the direction of the bus bar bodies  21 . 
     When each bus bar  15   a - 15   j  is fully received in the groove  25 , the lower edge of each projection  21   a  is flush with the bottom face of the upper case  12  (i.e. flush with the lower edges of the walls  25   a  and the lower edge of the peripheral wall of the upper case  12 ), which enables easy observation that each bus bar is correctly located. 
     To establish any particular desired arrangement of the bus bar circuits by electrically connecting the different bus bars  15   a - 15   j , electrical wires  31  are brought into pressure contact with the desired pressure contact blades  23 , as shown in FIG.  6 . Each wire  31  is, for example, a single core wire. The wires are brought into pressure contact with the desired pressure contact blades  23  by a pressure contact machine (not shown), and pressed into the slots in the blades  23  to fix the wires in position and establish electrical connection. The wires of the desired bus bars  15   a - 15   j  are thus electrically connected. Since the blades  23  are in rows, the wires  31  are laid linearly in the direction orthogonal with the direction of the bus bar bodies  21 . 
     Thereafter the lower case  13  is fitted to the bottom side of the upper case  12 , so that, as shown in FIG. 4, each rib  27  of the lower case  13  comes into direct contact with the rows of projections  21   a  of bus bars  15   a - 15   j . Thus, if the bus bars  15   a - 15   j  are not fully accommodated in the grooves  25 , the projections  21   a  are pressed by the ribs  27  to bring the bus bars  15   a - 15   j  to their correct positions on fitting of the lower case  13 . The bus bars  15   a - 15   j  and the wires  31  are now accommodated in the interior space of the electric connection box  11 . 
     FIGS. 2 and 3 show that the separating walls  25   a  have pairs of downward projections  25   b  at the locations of the pressure contact blades  23 . The projections  25   b  support the blades  23  laterally, e.g. during the operation of inserting the interconnecting wiles  31 . Furthermore, when the lower case  13  is connected to the upper case  12 , the lower ends of the pressure contact blades  23  are received in the grooves  26 , so that the separating walls  26   a  also act to support the pressure contact blades  23 . In this embodiment there are no terminals (such as tab terminals) projecting from the bus bars  15   a - 15   j  through the lower case  13 , which therefore acts as a base of the connection box  11 , enclosing and protecting the wires  31  and the pressure contact blades  23 . The wires  31  and contact blades  23  are thus well protected and supported in position against external forces, e.g. when connectors are pushed onto the tab terminals  22 , ensuring high reliability of the internal wiring of the connection box. 
     By cutting to eliminate selected parts of bus bars  15   a - 15   j , it is possible to adapt the bus bar circuits to a particular desired arrangement, with wide choice. For example, the bus bar body  21  may be cut to eliminate a portion shown by the broken lines C 1  in FIG. 5, to separate the bus bar into two parts which are electrically isolated. Various forms of the bus bars are obtainable as shown, for example, in FIG.  6 . 
     Furthermore, if it is wanted to make mutual electrical connection between non-adjacent bus bars, for example as shown in FIG. 6 to connect electrically the bus bar  15   f  and the bus bar  15   j , selected pressure contact blades  23  in one transverse row thereof are cut off to remove them, e.g. by cutting on the line C 2  in FIG. 5. A wire  31  is brought into pressure contact with the remaining pressure contact blades  23  of the bus bars  15   f , 15   j . Various bus bar circuits are thus obtainable as shown, for example, in FIG.  6 . 
     In this embodiment, the following effects can be obtained: 
     (1) As the bus bars  15   a - 15   j  are provided with the pressure contact blades  23 , when an electrical wire  31  is brought into pressure contact with, for example, the pressure contact blades  23  of two adjacent bus bars, the two bus bars can be electrically connected. In other words, there is no necessity as in a conventional electric connection box to fix connection terminals engageable with the tab terminals  22  to the ends of the electric wires  31 . Accordingly, it is easy to carry out electrical connection between the different bus bars. 
     (2) In each of the bus bars  15   a - 15   j , no tab terminal  22  is provided on the side where the pressure contact blade  23  is provided. Accordingly, even when the tab terminals  22  are in a crowded arrangement, the electrical wire  31  can be easily brought into contact with the pressure contact blade  23 . 
     (3) When the electrical wire  31  is brought into pressure contact with the pressure contact blades  23  of the bus bars  15   a - 15   j , the wire  31  can have a linear form (straight line). Accordingly, the wire  31  can be reliably brought into contact with the blades  23 . Also, in addition, as the bus bars  15   a - 15   j  are accommodated in the grooves  25  in parallel, the position of each pressure contact blade  23  can be easily computed. Therefore, positioning of the wires  31  can be easily done automatically. 
     Moreover, as a plurality of the blades  23  are formed on each of the bus bars  15   a - 15   j , the wires  31  can be brought into pressure contact with the desired bus bars  15   a - 15   j  in various modes. The contact blades  23  are at equal distances apart, so that wire positioning by a pressure contact machine can be easily performed. 
     (4) In the known electrical connection box as described above, because wires in the box cannot be used to make electrical connection between the different bus bars, it is necessary to connect the electric wires to the tab terminals outside the box. Accordingly, when mounting the electrical connection box in a vehicle, the wires become an obstacle. For this reason, space for accommodating the wires is required, and it is necessary to use a large space for mounting the electric connection box in a vehicle. In contrast, in the electrical connection box  11  of this embodiment, the wires  31  are accommodated in the box, and not exposed outside the box. For this reason, there is no requirement for space for the wires  31  in the vehicle, and there is no necessity to use a large space for mounting the electric connection box  11  in the vehicle. 
     In addition, as the wire  31  is not exposed outside the box, improved waterproof performance is obtained. Moreover, due to no intervention of connection terminals between the wires and the bus bars  15   a - 15   j , increase of electric contact resistance can be prevented, and reliability can be improved. 
     The embodiment of the present invention shown may be modified as follows: 
     In the above embodiment, tab terminals  22  project on only one side of the bus bars  15   a - 15   j , and the pressure contact blades  23  project on only the other side. However, as shown in FIG. 7, at the side at which the pressure contact blades  23  project, tab terminals  22  may be provided, e.g. to project symmetrically as shown in the figure. 
     Also, as shown in FIG. 8, at the side at which the pressure contact blades  23  project, tab terminals  22  may be provided staggered with respect to the terminals  22  at the upper side, and pressure contact blades  23  may be provided on both sides. 
     With such an arrangement the connector housings  24  may be formed on both the upper case  12  and the lower case  13 , so that the number of the connectors fitted to the connection box  11  can be increased. Furthermore, by providing pressure contact blade  23  on both sides of the bus bar body  21 , locations for wires  31  can be increased. 
     The pressure contact blades  23  are arranged in rows orthogonal to the direction of extension of the bus bar body  21 , but this is not necessary. 
     The projections  21   a  provided on the bus bar body  21  may be omitted. In this case, pressure contact blades  23  can be formed in place of the projections  21   a.    
     The ribs  27  provided on the top face of the lower case  14  may be omitted. When such provision is made, the lower case  14  can have a simpler construction. 
     In the foregoing embodiments all the bus bars  15   a - 15   j  are formed with the same configuration. However, these bus bars  15   a - 15   j  may be of mutually different configurations. 
     In the embodiment of FIGS. 1 to  6 , because there is no projection of tab terminals to the side provided with the pressure contact blades, the tab terminals do not become obstacles in making pressure contact of wires with the pressure contact blades. For this reason, the wires can be easily brought into pressure contact with the pressure contact blades. 
     Furthermore, the wires may extend in straight lines orthogonally to the bus bars. For this reason, the wires can be reliably brought into pressure contact with the pressure contact blades. Moreover, as the bus bars are disposed parallel with one another, the position of each pressure contact blade can be easily computed. Consequently, in carrying out pressure contact of the electric wires automatically using a pressure contact machine, position setting of the electric wires to the individual pressure contact blades can be easily achieved. 
     In other embodiments, when the connector housings  24  are provided on both the first and the second cases and the tab terminals project on both sides of the bus bar body, the numbers of the connectors attached to the connection box can be increased. Also, when the pressure contact blades are provided on both sides of the bus bar body, the locations of the wires  31  can be increased. 
     While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.