Abstract:
A unit assembling error prevention structure consists of a first unit, a second unit, a plurality of fixing means arranged at equal pitches, with which to assemble the first and second units together, two types of positioning frames, large and small, provided in an alternate manner on one of the first and second units, and a projection means provided on the other of the first and second units. The projection means is capable of advancing into the large positioning frame, but abuts against the small positioning frame. A pitch discrepancy is prevented at the time of assembling a battery connection plate or the like to a battery assembly or the like.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a unit assembling error prevention structure for preventing a pitch discrepancy when assembling, for example, a battery connection plate, a unit to be assembled to a battery assembly of an electric vehicle. 
     2. Description of the Related Art 
     FIG. 5 shows a first example of a conventional unit assembling structure. 
     This structure fixes a unit of an elongated harness protector  50  to an outer wall  52  of a mating unit of a device  51  with small screws (fixing means)  53 . The device  51  is installed, for example, on a vehicle and connected to a power source (not shown) through a wiring harness  54  inside the harness protector  50 . 
     The harness protector  50  is made of synthetic resin into rectangular trough-like shape and is provided at both sides of its trough-like portion  55  with a plurality of brackets  56  disposed at equal pitches. The wiring harness  54  is received inside the trough-like portion  55  and fixed therein with a wound vinyl tape  57 . Each bracket  56  is fixed to the outer wall  52  of the device  51  with the small screws  53 . 
     The wiring harness  54  has a plurality of branch lines  58  which extend at substantially equal pitches from an intermediate portion of the harness protector  50 , and a connector  59  at the tip end of each branch line  58  is fitted and connects to a connector (not shown) situated on the outer wall  52  of the device  51 . The main line of the wiring harness  54  extends out at both ends of the harness protector  50  and is led inside the device  51  through apertures  60  formed in the outer wall  52 . 
     With the above construction, however, when to install the harness protector  50  on the device outer wall  52 , an operator, during fixation of the brackets  56  to the outer wall  52 , may accidentally have the holes (not shown) of the brackets  56  misaligned or mismatched by one pitch in the longitudinal direction of the harness protector  50  with the threaded holes (not shown) of the outer wall  52 . Consequently, a false connection is made between the branch line connectors  59  and the device  51  side connectors. 
     FIG. 6 shows a second example of a conventional unit assembling structure. 
     This structure fixes and connects units, i.e., a pair of elongated battery connection plates  62 ,  62 ′ to both ends of a mating unit of a battery assembly  63 . The battery assembly  63  is installed on an electric vehicle inclusive of a hybrid car, and the battery connection plates  62 ,  62 ′ connect the batteries  65  ( 65   1 ,  65   2  . . . ) of the battery assembly  63  in series through a plurality of busbars  70  ( 70   1 ,  70   2  . . . ) thereof of conductive metal. 
     The batteries  65 , each having a thin rectangular parallelepiped shape, are joined in a width direction thereof and fixed one another with a band  66 . Each battery  65  has at its longitudinal ends a positive and negative electrodes  67  ( 67   1 ,  67   2  . . . ) or externally threaded terminals (fixing means) such that positive and negative electrodes  67  are arranged in an alternating manner at equal pitches P in the joining direction of the batteries  65 . 
     Each battery connection plate  62 ,  62 ′ consists of a plate body  68  of synthetic resin which is substantially the same in length as the entire width of the battery assembly  63 , a busbar  70  disposed in a plurality of rectangular grooves  69  formed on the plate body  68 , and a cover  72  of synthetic resin rotatably provided via a hinge  71  to the plate body  68 . 
     The busbars  70  are disconnected and independent from one another. One of the battery connection plates  62  is provided at both ends with a substantially square busbar  70   1  having one insertion hole  73   1  for the electrode  67   1  located at both left and right ends of the battery assembly  63 . Each busbar  70   2  located at a longitudinally intermediate portion of the plate body  68  is rectangular in shape and has two insertion holes  73   2 ,  73   3  for electrodes  67   2 ,  67   3  of two batteries  65   2 ,  65   3 . The busbar insertion holes  73  are provided at equal pitches, corresponding to the electrodes  67 . The plate body  68  has relatively large circular holes  74  arranged at equal pitches at its rear side for receiving the electrodes  67 . A plurality of busbars  70 , each having two insertion holes  73 , are disposed in the other battery connection plate  62 ′. 
     To describe with one of the battery connection plates  62  in FIG. 6, on assembling the battery connection plate  62  to the battery assembly  63 , the positive electrode  67 of the battery  65   1  at the left side end enters the insertion hole  73   1  of the left-side end busbar  70   1 . Likewise, the negative electrode  67   2  of the second-from-left battery  65   2  enters one of the insertion holes  73   2  of the second-from-left busbar  70   2 , and the positive electrode  67   3  of the third-from-left battery  65   3  enters the other insertion hole  73   3  of the second-from-left busbar  70   2 , with the remaining electrodes  67  entering the insertion holes  73  of the remaining busbars  70 . Each electrode  67  is tightened and connected to related busbars  70  with a nut  75 . The electrodes  67   1  . . . at the left and right side ends connect through the busbars  70   1  . . . and not-shown plate terminals to a power source line (not shown). 
     On assembling the battery connection plate  62 , a series circuit  76  as shown in FIG. 7 is constituted. Denoted  62  is the battery connection plate,  63  the battery assembly,  67  positive and negative electrodes, and  70  the busbars. 
     Reverting to FIG. 6, after each busbar  70  has been fastened and connected to the battery electrodes  67  with the nut  75 , the cover  72  is closed to protect the busbars  70 , electrodes  67 , nuts  75  and the above plate terminals (not shown) in the plate body  68 . The battery connection plate  62  thus also serves as a protector. The cover  72  has locking frames  77  engageable with locking projections  78  of the plate body  68  to lock the cover  72  in closed position. 
     With the above construction, however, there is worry that an operator, during assembling the battery connection plate  62  to the battery assembly  63 , may connect the busbars  70  to the battery electrodes  67 , with an inadvertent error made in aligning or matching the busbar insertion holes  73  with the battery electrodes  67  by one pitch. In this instance, as shown in FIG. 8, a closed circuit  79  as indicated by an arrow X is formed in the battery assembly  63 , possibly causing a short circuit and sparks, and damages to batteries  65 . In FIG. 8, denoted  62  is the battery connection plate,  67  the positive and negative electrodes, and  70  the busbars. 
     SUMMARY OF THE INVENTION 
     This invention has been accomplished to overcome the above drawbacks and an object of this invention is to provide a unit assembling error prevention structure which enables assembling a unit having fixing means at equal pitches such as a harness protector or a battery connection plate reliably to a mating unit such as a device or a battery assembly without a pitch discrepancy therebetween. 
     In order to attain the object, according to this invention, there is provided a unit assembling error prevention structure which comprises: a first unit; a second unit; a plurality of fixing means arranged at equal pitches, with which to assemble the first and second units together; two types of positioning frames, large and small, provided in an alternate manner on one of the first and second units; and a projection means provided on the other of the first and second units, which is capable of advancing into the large positioning frame, but abuts against the small positioning frame. 
     Preferably, the projection means comprises a pair of projections capable of advancing at opposite sides in the large positioning frame. 
     Preferably, the pair of projections each comprises walls intersecting at right angles. 
     Advantageously, the large positioning frame is replaced by an empty space. 
     Advantageously, the first unit comprises a battery connection plate, the second unit comprises a battery assembly, and the plurality of fixing means comprises electrodes of batteries constituting the battery assembly, the two types of positioning frames are provided on the battery connection plate, and the projection means is provided on every two of the batteries. 
     Preferably, the battery connection plate comprises a plurality of busbar receiving portions, and the two types of positioning frames, large and small, are provided on each of the busbar receiving portions. 
     Preferably, the plurality of busbar receiving portions are linked with resilient hinges to be movable relative to each other, and the positioning frames provided on each of the busbar receiving portions have a wall divided by a slit for each of the positioning frames and a wall opposite that wall, which is continuous for two or more of the positioning frames. 
     The above and other objects, features and advantages of this invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of one example of a battery connection plate to which a unit assembling error prevention structure according to this invention is applied; 
     FIG. 2 is a partial plan view of a battery assembly as a mating unit; 
     FIG. 3 is a partial perspective view of a battery in FIG. 2; 
     FIG. 4 is a plan view of a unit assembling error prevention structure according to this invention; 
     FIG. 5 is a perspective view of a first example of a conventional unit assembling structure; 
     FIG. 6 is an exploded perspective view of a second example of a conventional unit assembling structure; 
     FIG. 7 is an explanatory view of a series circuit in the second example above; and 
     FIG. 8 is an explanatory view of a closed circuit formed at the time of a false assembly in the second example above. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of this invention will now be described with reference to the attached drawings. 
     A battery connection plate  1  includes a plate body  2  of synthetic resin, a frame-like positioning section  3  integrally provided at one end of the plate body  2 , a cover  4  rotatably provided via hinges  5  at the other end of the base plate  2 , and a plurality of busbars  10  disposed on the plate body  2 . The integrally provided frame-like positioning section  3  features the battery connection plate  1  in this example. 
     The plate body  2  has busbar receiving portions  7  linked end-to-end with a resilient hinge  8  and is capable of absorbing a positional discrepancy. Such an arrangement has been proposed in another application. Each busbar receiving portion  7  is formed box-like and receives a busbar  10  on its bottom wall (not shown) though its upper opening  9 . The hinge  8  is integrally formed with adjoining side walls  11  of neighboring busbar receiving portions  7 . 
     Each busbar  10  is locked in place by resilient claws  14  provided on front and rear walls  12 ,  13  of busbar receiving portion  7 , each of which claws is cut and raised from the wall  12 ,  13 . Each busbar  10  is provided with two insertion holes  16  for related externally threaded electrodes  15  of the battery assembly  6  (FIG.  2 ). The busbars  10  used in this example have the same size and shape. The bottom wall of each busbar receiving portion  7  is provided with holes (not shown) larger than the insertion holes  16 . 
     The battery assembly  6  (FIG. 2) is assembled to the bottom walls of the battery receiving portions  7 , with the battery electrodes  15  (FIG. 2) protruding through the related insertion holes  16  into the interior of the busbar receiving portions  7 , and tightened and connected to the busbars  10  with nuts (not shown). 
     The front and rear walls  12 ,  13  defining the busbar receiving portions  7  are slit in the immediate vicinity of each hinge  8  so that the busbar receiving portions  7  are movable relative to one another. At an outer side of the front wall  12  is integrally provided the frame-like positioning section  3  which is constituted by two kinds of rectangular frames  18 ,  19 , large and small. 
     In this example, a large and small frames  18 ,  19  are juxtaposed to each busbar receiving portion  7  except for the right side end busbar  7   1 . To the right side end busbar receiving portion  7   1  is juxtaposed only one, small frame  19   1  at a side toward the neighbor busbar receiving portion. The large and small frames  18 ,  19  are alternated in the order of small and large from the right side end of the positioning section  3 . 
     The large and small frames  18 ,  19  are linked to each other via a common partition wall  20  extending perpendicularly to the front wail  12  of the busbar receiving portion  7  at a position slightly displaced leftward from a longitudinal center of the busbar receiving portion  7 . Each frame  18 ,  19  opens upwardly and downwardly and has a respective positioning space  23 ,  24  defined by the surrounding walls, i.e., the front wall  12  of the busbar receiving portion  7 , a left and right partition walls  20  or side end wall  21 , and an outer (foremost) wall  22 . The outer wall  22  is provided at its upper end with locking projections  25  for the cover  4 , the locking projections being located at a longitudinal center of large frames  18 . 
     The cover  4  includes a plate-like body  26 , an upright wall  27  formed at one end of the body  26  and the thin-wall hinges  5  extending at the other end of the body  26 . The upright wall  27  is formed with pairs of an engagement piece  29  having an engagement hole  28  for the related locking projection  25  and a guide plate  30  opposed to the engagement piece. The body  26  is formed at the other end with positioning cutouts  32  for external rectangular protuberances  31  of the plate body  2 . The protuberances  31  engage in the cutouts  32  to position the cover  4  during its rotation, so that the engagement pieces  29  are accurately guided to the respective locking projections  25 . 
     On closing the cover  4 , the guide plate  30  advances along an inner surface of the outer wall  22  at large frame  18  slightly into the space  23 , and the engagement piece  29  is located along and parallel to an outer surface of the outer wall  22  at large frame  18 . The guide plate  30  and the engagement piece  29  hold therebetween the outer wall  22  at the large frame  18 , so as to provide greater rigidity in the large frame  18  and stably maintain the large frame  18  in shape. 
     Referring now to FIG. 2, a battery assembly  6  has a plurality of batteries  17  joined in parallel in a width direction thereof. Each battery  17  has an external thread terminal or electrode (fixing means)  15  projecting at both longitudinal ends thereof (only one side ends are shown in FIG.  2 ). The batteries  15  are arranged, for example, in the order of positive, negative, positive from the left. 
     A pair of engagement projections  34  are formed on, for example, the positive-electrode side end surfaces  33  of every two batteries  17 , in the vicinity of the electrodes  15 , which engagement projections  34  engage in the related large frame  18  of the positioning section  3  to set the battery connection plate  1  (FIG. 1) in position on the battery assembly  6 . Each projection  34 , as shown also in FIG. 3, is L-shaped and includes a major wall  36  parallel to a side surface  35  of the battery  17  and a minor wall  37  extending at right angles from the major wall  36  at a side toward the electrode  15 . The pair of opposed engagement projections  34  are in a symmetrical arrangement. The projections  34  are integrally molded with a battery housing  38  of synthetic resin. Alternatively, a plate member (not shown), for example, having the projections  34  may be retrofitted to the battery housing  38  or the battery assembly  6  (FIG.  2 ). 
     In FIG. 2, the outer width dimension L 1  of the pair of projections  34 ,  34  is set slightly smaller than the longitudinal (major) inner width dimension L 3  (FIG. 4) of large frame  18  of the battery connection plate  1  (FIG.  4 ), and the length L 2  of the pair of projections  34  is set slightly smaller than the minor inner width dimension L 4  of the large frame  18  (FIG.  4 ). The inner width dimension L 4  is the same for the large and small frames  18  and  19  (FIG.  4 ). The pairs of projections  34 ,  34  have the same outer width dimension L 1  and the same length L 2 . The height H (FIG. 3) of each pair of projections  34 ,  34  is set equal to or smaller than that of the large frame  18 . 
     The inner width dimension L 3  (FIG. 4) of large frame  18  is slightly smaller than the width of battery  17 , and the inner width dimension L 5  (FIG. 4) of small frame  19  is smaller than the inner width dimension L 3  of the large frame  18  substantially by the widths L 6  of both lateral partition walls  20 . The inner width dimension L 5  of the small frame  19  is set smaller than the outer width dimension L 1  (FIG. 2) of the pair of projections  34 ,  34 . The inner width dimension L 5  plus twice the width L 6  (FIG. 4) of the partition wall  20  is larger than the minimum inner width dimension L 7  (FIG. 2) of the pair of projections  34 ,  34 . 
     In FIG. 2, the batteries next to the batteries  17  having the projections  34  on their one end surfaces  33  have like pairs of projections  34  on their not-shown other end surfaces so that the battery connection plate  1  (FIG. 1) is longitudinally positioned at the opposite ends of the battery assembly  6 . If the electrode  15  at one end is positive, the electrode  15  at the other end is negative, and the projections  34  are, for example, provided at the positive electrode sides of the assembled batteries  17 , making it possible to commonly use the batteries  17 . The battery connection plate (not shown) assembled at the other end of the battery assembly  6 , like the battery connection plate  62  in FIG. 6, carries one-hole busbars at longitudinally opposite ends thereof. 
     As shown in FIG. 4, the battery connection plate  1  is assembled to the battery assembly  6 . The battery connection plate  1  is shown simplified as compared with that in FIG.  1 . Concurrently with inserting the externally-threaded electrodes  15  of the batteries  17  into the insertion holes  16  of the busbars  10  carried on the plate body  2 , the pairs of projections  34 ,  34  provided on every two batteries advance into and engage with the respective large frames  18  of the positioning section  3 . Each busbar  10  has the two, left and right side insertion hole  16  and is locked in the respective busbar receiving portion  7  with the resilient claws  14 . 
     During the assembly of the battery connection plate  1 , if the electrode  15  is misaligned by one pitch and entering the neighbor insertion hole  16   1  in the busbar  10 , the pair of projections  34 ,  34  abut, at their tip ends  34   a , against the opposite partition walls  20  of the small frame  19 , thereby to hinder the assembly of the battery connection  1  to the battery assembly  6 . An false assembling of the battery connection plate  1  is thus prevented, and no closed circuit is formed in the battery assembly  6  as in the described related art. The positive and negative electrodes  15 ,  15   1  of two batteries  17 ,  171  are connected in series with one busbar  10 , so as to constitute the battery assembly  6  of large voltage as a whole. 
     By the pair of projections  34 ,  34  engaging in the large frame  18  with substantially no clearance therebetween, there can be obtained an improved retention of the battery connection plate  1  on the battery assembly  6 , making it possible to prevent rattling of the battery connection plate  1  due to vehicle vibrations, loosening of the nut (not shown) tightened on the electrode  15 , and damages to the resin-made battery connection plate  1 . Further, if an error is made in arranging the batteries  17  (for example, confusion of positive electrode  15  with negative electrode), because the tip ends  34   a  of the projections  34  abut against the partition walls  20  of the small frame  19 , a false assembly of batteries  17  can be detected. 
     Since, at the time of assembling, electrodes  15  are inserted into the busbar insertion holes  16 , if an assembling error of the battery connection plate  1  takes place, the positional deviation of the battery connection plate  1  will be at most as much as one pitch of the electrodes  15 . Accordingly, it suffices that the projections  34  are provided with a minimum size needed to abut against the partition walls  20  of small frame  19  or with a substantially L-like intersecting shape as in the present embodiment. The projections  34  are thus made compact and lightweight, and a reduction is attained in the material cost and molding cost of the projections  34 . 
     Since the minor walls  37  (FIG. 3) of the L-shaped projections  34  extend perpendicularly to the partition walls  20  of the small frame  19 , the minor walls  37  are effective as an abutment member and serve to suppress horizontal and vertical and rotational rattling of the battery connection plate  1  on the battery assembly  6 . Of course, the projections  34  may be replaced by one large rectangular block of such size as to correspond to the inner sizes L 3 , L 4  of the large frame  18 . 
     If the electrode  15  or externally threaded terminal of the battery  17  deviates radially from position due to a manufacturing error, runout or the like (positional deviation will be about 0.35 mm at the most), the resilient hinge  8  (FIG. 1) allows the related busbar receiving portion  7  to move slightly in the deviation direction to absorb the discrepancy on a busbar receiving portion basis and allow smooth insertion of the electrode  15  into the related insertion hole  16  of the busbar  10  (FIG.  4 ). In this instance, because the front wall  12  is divided at the large frames  18  by the slit  42  (FIG. 1) in the vicinity of the side walls  11  of the busbar receiving portions  7 , the large and small frames  18 ,  19  contiguous to the moved busbar receiving portion  7  become slightly contorted in parallelogram, causing the partition wall  20  between the frames  18  and  19  to slightly bend slantingly. 
     The bending of the partition wall  20 , however, is slight, and besides, the outer wall  22  of the frames  18 ,  19  does not move, it being longitudinally continuous and integral with the walls  12  of the busbar receiving portions  7   1 ,  7  at both longitudinal ends, so that the large and small frames  18 ,  19  are stably kept in position or shape without substantial positional deviation. Thus, the compatibility with the projections  34  of the battery  17  is always maintained satisfactory, irrespective of the positional discrepancy absorbing action by the resilient hinge  8 . 
     In FIG. 1, the battery connection plate  1  is provided, at one of its longitudinal ends, not with the large frame  18 , but with an empty space  44  inside which, as shown in FIG. 4, the pair of projections  34 ,  34  are located on assembling the battery connection plate  1 . Like this, the large frames  18  may be disused or the outer wall  22  at the large frames  18  may be cut out to provide only the small frames  19  at alternate positions. In this case, the locking projection  25 , engageable with the cover  4  (FIG.  1 .), is provided on the outer wall  22  at small frames  19 . 
     Because there is provided a space  45  (FIG. 4) between the paired projections  34 ,  34 , when assembling, the guide plate  30  (FIG. 1) at the rotation leading side of the cover  4  is situated between the paired projections  34 ,  34 , without interfering with the projections  34 ,  34 . Incidentally, it may be arranged that the projections  34 , in case the battery connection plate  1  is falsely assembled, abut against the guide plate  30  (FIG. 1) of the cover  4  to detect the abnormality. 
     While the above example concerns the assembling error prevention structure for the battery connection plate (unit)  1  which is assembled to the battery assembly  6  of an electric vehicle, the same structure is also applicable to prevent an assembling error between a harness protector of synthetic resin and a device, apparatus or the like as in the described related art. 
     In this case, the battery assembly  6  in FIG. 4 corresponds to the mating unit such as a device, apparatus or the like, and the battery connection plate  1  to the harness protector (unit) which receives a wiring harness. Preferably, in place of the electrode  15  or bolt in FIG. 4, bevel locking clips (not shown) having a pair of resilient claws are provided on the harness protector, and engagement holes (not shown) for the locking clips are provided on a wall of the mating unit. Further, instead of providing the large and small frames  18 ,  19  on the unit and the projections  34  on the mating unit, it is also possible to provide the large and small frames on the mating unit and the projections on the unit. 
     Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth herein.