Branch junction box and busbars for branch connection

Branch connection busbars to be firmly installed in upper and lower cases each have upper and lower series of branched tabs projecting upwardly and downwardly from the upper and lower lateral edges of the busbar, respectively, through tab connecting portions, with the upper and lower series of branched tabs staggered. The upper and lower cases are each provided at their opposing contact surfaces with seats. The branch connection bushbars are first installed into the lower case with the upwardly projecting branched tabs held firmly by the seats of the lower case. At the same time the downwardly projecting branched tabs are passed through tab insertion holes in the lower case. As the upper case is assembled onto the lower case, the upwardly projecting branched tabs are inserted into the tab insertion holes in the upper case and the seats of the upper case are held against the bottom of the downwardly projecting branched tabs. Thus, the upper and lower branched tabs are firmly held between one case and the seats of another case, preventing the branched tabs and busbars from being dislocated by external force produced when external connectors are mounted or dismounted.

BACKGROUND OF THE INVENTION 
The present invention relates to a branch junction box for interconnecting 
wiring harnesses in automobiles and also to comblike branch connection 
busbars used for forming branched circuits in the branch junction box. 
PRIOR ART 
A branch junction box is used for interconnecting electric wires in 
automobiles and has an advantage of accommodating joints of wiring 
harnesses to simplify the wiring configuration. 
A method of making concentrated branched circuits which is currently 
available (as disclosed in the Japanese Patent Preliminary Publication No. 
Showa 61-45575) consists, as shown in FIG. 14, of the steps of: drawing 
out a group of wires 2A from wiring harnesses 1; placing the drawn-out 
parallel wires between an upper case 3 and a lower case 4; pushing a wire 
into a U-shaped slot 6a of a pressure contact portion 6 of a pressure 
terminal 5; projecting a branched tab 7 of the pressure terminal 5 through 
a hole or pit 3a in the upper case 3 to form a connector mounting portion 
8; and then inserting a connector 9 of other group of wires 2B into the 
connector mounting portion 8. 
Another interconnecting structure proposed by this applicant (in the 
Japanese Patent Application No. Showa 63-131708), as shown in FIG. 15, has 
one lateral edge of straight busbars 10 installed into busbar 
accommodating grooves 4a in a lower case 4' so that the busbars are 
arranged in parallel with each other, with other lateral edge of the 
busbars 10 pressed into U-shaped slots 6a' of pressure contact portions 6' 
of pressure terminals 5'. 
The branch junction box shown in FIG. 14 is assembled integrally with the 
wiring harness 1, so that the assembly work cannot be performed 
separately, which is disadvantageous for the process control and inventory 
management. In the branch junction box of FIG. 15, the interval D between 
the adjacent busbars 10.sub.1 and 10.sub.2 is restricted by the width D' 
(D&gt;D') of the pressure terminal 5', making high-density busbar arrangement 
difficult, which in turn will lead to an increased size of the branch 
junction box. Further, the busbars 10 and pressure terminals 5' are formed 
of rigid material such as punched-out metal plate. When, as shown in FIG. 
16, the branched tab 7' is not correctly aligned with the associated holes 
3a when the upper case 3 is mounted, the pressure terminal 5' becomes 
tilted, distorting the pressure contact portion 6', which, when the 
distortion exceeds the limit of elasticity, will sustain a plastic 
deformation, resulting in an open or broken circuit. 
It is an object of this invention to provide a branch junction box which 
has high busbar circuit integration and thus can be formed compact and 
which prevents poor contact between the branched tabs and the busbars. 
Another object of this invention is to provide branch junction box of a 
construction that can reliably prevent current leakage between busbars. 
A further object of the invention is to provide a branch junction box of a 
construction that allows an increase in the number of internal circuits 
without changing the lateral dimensions of the case and that permits 
fixing and positioning of the branched terminals. 
A further object of the invention is to provide comb-shaped, branch 
connection busbars which can be punched out and formed by a single die and 
which can be used commonly in the manufacture of busbars with different 
numbers of poles of branched tabs. 
SUMMARY OF THE INVENTION 
The branch junction box of this invention comprises: an upper case and a 
lower case; a plurality of connector insertion portions provided on the 
upper case; a plurality of parallel busbar accommodating grooves formed in 
the lower case at equal intervals; and a plurality of busbars each having 
one lateral edge thereof installed in the busbar accommodating groove and, 
at the other lateral edge, having branched tabs projected upwardly 
therefrom through tab connecting portions into the connector insertion 
portions; the tab connecting portions each consisting of a rising piece 
extending upwardly from the second lateral edge of the busbar, and a tab 
connecting piece extending laterally on one side or both sides of the 
rising piece; whereby the tab connecting pieces are bent at right angles 
to the plane of the busbar so that the branched tabs on them will protrude 
sideways from the busbar, the tab connecting pieces are further extended, 
as required, to cross adjacent busbars, and the extended portions of the 
tab connecting pieces are formed with upwardly projecting branched tabs. 
In a preferred embodiment of the invention, the busbars are formed with 
notches at intersecting points with the tab connecting pieces, to prevent 
current leaks between the busbars. 
In the above construction, since the branched tabs are formed integral with 
the busbar--a construction which is different from the pressure terminals 
5, 5' of FIGS. 14 and 15--there is no possibility of bad contact and the 
contact pressing process can be eliminated reducing the number of assembly 
processes for the branch junction box. 
The interval between the busbars need only be slightly wider than the bent 
portion of the tab connecting piece (or the width of the branched tab), 
permitting a high density circuit arrangement as a whole, which in turn 
leads to a reduction in the size of the branch junction box. 
Where there is a need to lead out three or more poles of branched tab from 
the same part of the busbar, this can be accomplished by a tab connecting 
piece which extends to cross the adjacent busbars. This arrangement makes 
it easy to perform the branched tab alignment for each connector (or for 
each connector insertion portion). 
To reliably prevent the current leakage between the busbars, it is also 
preferred that a plurality of busbar accommodating grooves arranged 
parallel with each other at specified intervals be formed in opposing 
contact surfaces of the upper and lower cases and that raised and recessed 
walls that engage each other be provided to the opposing contact surfaces 
of the upper and lower cases between and along the busbar accommodating 
grooves. 
With this construction, since the adjacent busbars are isolated from each 
other by the engagement of the raised wall and the recessed wall, the 
current leak between the busbars can reliably be prevented even when water 
seeps into the branch junction box. 
Further, a branch junction box of the present invention which allows the 
number of circuits to be increased without changing the lateral dimensions 
of the case and which permits reliable fixing and positioning of the 
branched terminals has a construction which comprises: branch connection 
busbars each consisting of a strip of busbar, a plurality of tab 
connecting portions provided on the upper and lower lateral edges of the 
busbar, and a plurality of branched tabs projecting upwardly and 
downwardly from the upper and lower tab connecting portions, respectively, 
the upper and lower tab connecting portions being staggered; a pair of 
upper and lower cases for accommodating the branch connection busbars in 
such a manner that the busbars are parallelly arranged at specified 
intervals and that the upper and lower groups of branched tabs on the 
branch connection busbars are aligned in a direction perpendicular to the 
busbars, the upper and lower cases having tab insertion holes; a plurality 
of connector insertion portions provided to the outer surfaces of the 
upper and lower cases at positions corresponding to the upper and lower 
groups of branched tabs so that the connector insertion portions on the 
upper case and those on the lower case are staggered; and a plurality of 
seats provided to the inner surfaces of the upper and lower cases at 
positions corresponding to the lower and upper tab connecting portions; 
whereby the upper and lower branched tabs on each branch connection busbar 
are passed through the tab insertion holes in the upper and lower cases 
and projected into the connector insertion portions, and the upper and 
lower tab connecting portions are firmly held between one case and the 
seats of the other case. 
To facilitate the work of assembling the branch connection busbars into the 
upper and lower cases and also the work of positioning the branched tabs, 
it is also preferred that the seats of at least one of the upper and lower 
cases are formed with insertion grooves into which the tab connecting 
portions are inserted. 
With the above construction since the upper and lower groups of tab 
connecting portions on the branch connection busbars are firmly held 
between one case and the seats of another case, the branched tabs and also 
the branch connection busbars can be prevented from becoming loose or 
dislocated by external force produced when external connectors are mounted 
to or dismounted from the connector insertion portions. 
Further, since the seats in one of the cases are provided with insertion 
grooves that guide the tab connecting portions into predetermined 
positions, the alignment of the branched tabs as well as the mounting of 
the other case (insertion of the branched tabs through the tab insertion 
holes) are made easy. 
Further comblike branch connection busbar, that can be used commonly in the 
manufacture of various kinds of busbars with different numbers of branched 
tab poles, has a construction in which a plurality of parallel branched 
tabs project perpendicularly from one side of a laterally extending base 
strip through perforated portions that are spaced at specified intervals.

PREFERRED EMBODIMENT OF THE INVENTION 
In FIG. 1 reference numeral 11 represents an upper case, on the upper 
surface of which are erected a plurality of connector insertion portions 
12A, 12B, . . . that each have an array of tab insertion holes 13 formed 
in their bottom walls. Denoted 14 is a lower case, in the upper surface of 
which a plurality of parallel busbar accommodating grooves 15 are formed 
at a constant pitch P. Designated 16 and 17 are engagement portions and 
engagement claws, that together form a locking means for locking the upper 
and lower cases 11, 14 together. 
Straight busbars 18 each have a plurality of branched tabs 19 erected at 
the upper lateral edge thereof through tab connecting portions 20. The 
lower edge of each straight busbar 18 is securely installed in the busbar 
accommodating groove 15. The branched tabs 19 pass through the tab 
insertion holes 13 and project into the connector insertion portions 12A, 
12B, . . . , to which corresponding connectors of wiring harnesses not 
shown are connected. 
FIG. 2 is an enlarged perspective view of a group of busbars 18 as shown in 
FIG. 1. In FIG. 2, the busbars are assigned reference numerals 18.sub.1, 
18.sub.2, 18.sub.3, 18.sub.4, from the front toward the rear, to make them 
distinguishable. 
The busbar 18.sub.1 has T-shaped tab connecting portions 20 formed integral 
with its upper edge and spaced from each other at pitches corresponding to 
the connector mounting portions 12A, 12B, . . . The T-shaped tab 
connecting portions 20 each consist of a rising piece 20a and tab 
connecting pieces 20b, extending laterally from each side of the rising 
piece 20a. The tab connecting pieces 20b each have a branched tab 19 
projecting upwardly from the lateral ends thereof. The tab connecting 
pieces 20b are bent at right angles with respect to the plane of the 
busbar 18.sub.1, so that the two branched tabs 19 are located between the 
busbars 18.sub.1 and 18.sub.2 and face each other at positions deviated 
sideways from the busbar 18.sub.1. One or both of the two branched tabs 19 
may be bent in the opposite direction as shown in an imaginary line 
(two-dot line). 
FIG. 3a is a developed view of the busbar 18.sub.1, tab connecting portions 
20 and branched tabs 19, punched out from a single conductive metal plate. 
Bending the tab connecting portions 20 along the dashed line Q forms the 
busbar 18.sub.1 with two-branch tabs 19 of FIG. 2. 
This busbar 18.sub.1 having the laterally symmetrical T-shaped tab 
connecting portions 20 constitute the basic structure of the busbars 
employed in the branch junction box of this invention. 
The busbar 18.sub.2 has a tab connecting portion similar to the one 
mentioned above at the center and also laterally non-symmetrical T-shaped 
tab connecting portions 21 and 22 on each side. FIG. 3b shows a developed 
view of the busbar 18.sub.2 and its integrally formed tab connecting 
portions 20, 21, 22. 
The tab connecting portion 21 has its left tab connecting piece 21b 
extended to cross the adjacent busbar 18.sub.3 until its front end reaches 
a point between the busbars 18.sub.3 and 18.sub.4, with two branched tabs 
19 projecting upwardly. On the other hand, the right tab connecting piece 
21b' has the same structure as the basic busbar structure. Similarly the 
tab connecting portion 22 has the left tab connecting piece 22b formed in 
the same construction as the tab connecting piece 21b, while the right tab 
connecting piece 22b', extends beyond the busbar 18.sub.4 and has three 
branched tabs 19. 
Notches 23 are formed in the busbars 18.sub.3 and 18.sub.4 where the tab 
connecting pieces 21b, 22b, 22b' cross these busbars, so as to prevent 
current leaks among busbars. The branched tabs 19 are of course not 
provided at the notches 23 in the busbars 18.sub.3, 18.sub.4. 
By elongating the tab connecting pieces 21b, 22b of the tab connecting 
portions 21, 22 across the adjacent busbar 18.sub.3, it is possible to 
extract a plurality of branched tabs 19 from the same point of the busbar, 
if necessary, and to arrange the branched tabs 19 in desired arrays for 
each of the connector mounting portions 12A, 12B, . . . 
As is evident from FIG. 2, the pitch P or interval between the busbars need 
only be slightly larger than the width W of the branched tab 19 (or the 
bent portion of the tab connecting piece 20b), allowing the busbars 
18.sub.1, 18.sub.2, 18.sub.3 to be arranged closer together. Even when the 
tab connecting piece 21b extends crossing the adjacent busbar 18.sub.3, 
the pitch P remains unchanged. Since the series of branched tabs 19 formed 
on each of the busbars 18.sub.1, 18.sub.2 can easily be formed by punching 
a conductive metal plate and bending the punched-out plate, as shown in 
FIGS. 3a and 3b, it is possible to make accurate position alignment 
between the branched tabs 19 and the tab insertion holes 13 in each 
connector mounting portion 12A, 12B, . . . 
In another embodiment shown in FIGS. 3c and 3d. the busbars 18 (18.sub.1 to 
18.sub.4), formed of a partly tin-plated copper-zinc alloy, have folded 
pieces 18a, 18b--which are bent 180 degrees--formed at the notches 23 and 
at the tab connecting pieces 21b, 22b of the tab connecting portions 21, 
22 that face the notches in order to enhance the current leakage 
prevention capability. 
That is, in FIG. 3, the busbars 18 and the branched tabs 19 are formed by 
punching and thus the conductive metal is exposed at the surface S of the 
notches 23 and at the lower end surface S of the tab connecting pieces 
21b, 22b that face the notches. The presence of water between these 
surfaces will form a bridge resulting in a current leakage. 
The folded pieces 18a, 18b, however, make such current leakage less likely 
because their opposing surfaces have the tin layer plated thereover, which 
is a poor conductor, preventing the formation of a current path between 
the conductive metals even when there is water bridging the opposing 
folded pieces. 
The 180-degree folded pieces 18a, 18b may be replaced with 90-degree folded 
pieces 18a', 10b' as shown in FIGS. 3e and 3f. 
Another embodiment shown in FIGS. 3g to 3p has an insulating plate 24' 
interposed between the busbars 18 and the branched tabs 19 to prevent 
current leakage between the busbars. As shown in FIG. 3h, the insulating 
plate 24' is formed, at positions corresponding to the array of branched 
tabs 19 of the busbars 18, with U-shaped insertion slits 24a' that receive 
the tab connecting portions 20 of the basic structure and also with 
insertion slits 24b', 24c' that receive the tab connecting portions 21, 22 
with varying number of branched tab poles. 
As shown in FIG. 3i, the insulating plate 24' is placed over the busbars 18 
mounted on the lower case 14 (see FIG. 1) in such a way as to allow the 
branched tabs 19 and the tab connecting portions 20 to 22 to pass through 
and project from the insertion slits 24a' to 24c'. Then the insulating 
plate 24' is slid in the direction of arrow R as shown in FIG. 3j. 
As a result, as shown in the cross-sectional views of FIGS. 3k to 3m and 
FIGS. 3n to 3p, the insulating plate 24' is securely held between the 
busbars 18 and the tab connecting portions 20 to 22 and isolates the 
branched tabs 19 and the adjacent busbars 18. Since the insulating plate 
24' is slid as shown, the tab connecting portions 20 to 22 and the 
branched tabs 19 are displaced from the insertion slits 24a, to 24c. 
Hence, if water attaches to the branched tabs 19 projecting from the 
insulating plate 24', there is no possibility of the water forming a 
bridge between the branched tabs 19 and the adjacent busbars 18 through 
the tab connecting pieces 20b (21b, 22b), further enhancing the current 
leakage prevention effect. 
This embodiment eliminates the need to provide the notches 23 for the tab 
connecting pieces 20b to 22b that extend across the busbars 18. This in 
turn permits the overall height of the branch junction box to be reduced. 
In FIGS. 4 and 5, the contact surface 25a of the lower case 25 is provided 
with three kinds of raised walls 34, 34', 34" along the busbar 
accommodating grooves 27. The raised wall 34 is provided at the middle of 
the two busbar accommodating grooves 27, 27; the second raised wall 34' is 
provided on each side of a hollow portion V formed in the lower case 25; 
and the third raised wall 34" is provided close to the outer edge of the 
lower case 25. 
The contact surface 24a of the upper case 24 is provided with recessed 
walls 35, 35', 35" that engage with the corresponding raised walls 34, 
34', 34". 
The height of each raised wall from the contact surface 25a is set 
sufficiently large so that the depth of engagement between the raised 
walls and the recessed walls is larger than the overstroke D between the 
locking claw 32 and the engagement portion 33, the locking claw 32 and the 
engagement portion 33 forming a locking portion. The width of each raised 
wall 34, 34', 34" is set equal to that of each recessed wall 35, 35', 35". 
These raised and recessed walls are preferably sized so that they can be 
engaged with each other in an air tight contact condition or in a pressure 
contact condition. 
In FIGS. 4 and 5, reference numerals 28 represents busbars, 29 connector 
insertion portions, 30 branched tabs, 31 tab insertion holes, and 32 and 
33 engagement claws and engagement portions, both forming a locking means. 
With this construction, even when water seeps into the branch junction box, 
the adjacent busbars 28 are isolated from each other by the engagement 
between the raised walls 34 or 34' and the recessed walls 35 or 35', so 
that current leakage among the busbars can be prevented. 
The raised wall 34 (34', 34") and the recessed wall 35 (35', 35 ") have the 
effect of increasing the distance that the water must move in seeping from 
one busbar accommodating groove 27 to another, thereby delaying and 
preventing the ingress of water. 
While in the above example, the raised walls are provided to the lower case 
25 and the corresponding recessed walls to the upper case 24, it is 
possible to reverse or even mix them. 
In the branch junction boxes that accommodate lateral busbars as internal 
circuit components, the above construction reliably prevents current 
leakage between busbars. 
In the branch junction box shown in FIG. 4, when one wants to increase the 
number of internal circuits and enhance the joint capacity, the length l 
of the case or its width w should be increased. However, the limited space 
in the automobiles restricts the lateral dimension of the junction box. 
A possible solution to this problem may be to form the rising pieces 37a of 
the tab connecting portions 37 on both the upper and lower edges of the 
busbar 36 alternately, as shown in FIG. 6 in which the branched tabs 38 
are shown provided on each side of the busbar 36 to form a branch 
connection busbar A. In this case, however, a wiring board of FIG. 1 (the 
lower case 14 with busbar accommodating grooves 15) to accommodate the 
busbars 18 cannot be used, giving rise to another problem of fixing the 
branched tabs 38. 
The branch junction box shown in FIGS. 7 to 18 has been realized to 
overcome the above drawback. 
In FIGS. 7 and 8, designated A and A' are branch connection busbars; 
denoted B and B' are an upper case and a lower case, respectively, both 
formed of synthetic resin. 
The branch connection busbar A' has the same basic construction as that of 
the branch connection busbar A. What the branch connection busbar A' 
differs from the latter busbar A is that the upper tab connecting portion 
37.sub.1 has its tab connecting pieces 37b.sub.1, 37b.sub.2 extended to 
cross the adjacent busbars 36 to form a five-pole branched tab 38. 
A plurality of branch connection busbars A, A' are arranged as follows and 
accommodated in the cases B, B'. The busbars 36 are parallelly arranged at 
certain pitches and upper and lower groups of the branched tabs 38 are 
arrayed in the directions of arrows R, R' perpendicular to the busbars 36. 
The upper case B and the lower case B' are provided on their outer surfaces 
with two connector insertion portions 41 and three connector insertion 
portions 41', respectively, at positions that correspond to the upper and 
lower groups of branched tabs 38 of the branch connection busbars A, A' so 
that the upper connector insertion portions each have an array of tab 
insertion holes 39 formed therein. 
A bottom wall 42 of the lower case B' is provided with a plurality of 
projecting seats 43 for the upper tab connecting portions 37 of the branch 
connection busbars A, A', the seats 43 being arrayed in the direction of 
arrow R. The upper end surface of each set 43 is cut with grooves 44 on 
each side, into which the tab connecting pieces 37b of the tab connecting 
portion 37 are inserted. 
As shown enlarged in FIG. 8, the seats 43 are each formed into a column and 
are arranged to provide a gap S therebetween to allow the busbar 36 to be 
inserted. The upper opening end of the insertion grooves 44 is provided 
with a tapered portion 44a as an insertion guide. 
A ceiling wall 42' of the upper case B is provided at its inner surface 
with a plurality of projecting seats 43' for the lower tab connecting 
portions 37 of the branch connection busbars A, A', as shown in FIG. 9. 
The seats 43' have the same dimensions as the aforementioned seats 43 but, 
in this embodiment, are not provided with the insertion grooves 44. 
Denoted 45 and 46 are engagement claws that form a locking means for the 
upper and lower cases B, B'. 
The assembly of the branched junction box is carried out in the following 
procedure. 
As shown in FIG. 9, the lower branched tabs 38 of the branch connection 
busbar A are inserted through the tab insertion holes 39 in the lower case 
B' into the connector insertion portion 41'. 
Since the seats 43 of the lower case B' have the insertion grooves 44 cut 
in the upper surface on each side, the tab connecting pieces 37b of the 
upper tab connecting portions 37 are guided along the tapered portions 44a 
into the insertion grooves 44 where they are securely held. As a result, 
the upper group of branched tabs 38 of the branch connection busbar A are 
positioned, aligning themselves with the tab insertion holes 39 in the 
upper case B. 
Then, the upper case B is mounted on the lower case B' and locked together 
by the locking means 45, 46. Now, the lower tab connecting portions 37 of 
the branch connection busbar A are clamped and securely held between the 
lower case B' and the seats 43' of the upper case B; and the upper tab 
connecting portions 37 are also firmly held between the upper case B and 
the seats 43 (insertion grooves 44) of the lower case B'. 
The branch connection busbar A' with five-pole branched tabs 7 is also held 
in the same way as the branch connection busbar A. In this branch 
connection busbar A', however, the tab connecting portion 37.sub.1 has its 
tab connecting pieces 37b.sub.1 and 37b.sub.2 on each side positioned and 
held by three seats 43 and by two seats 43, respectively. Thus, the number 
of poles of the branched tabs 38 in one tab connecting portion 37 can be 
increased or reduced to a desired number. 
While in the above embodiment the insertion grooves 44 are provided only to 
the seats 43 of the lower case B', it is also possible to eliminate the 
insertion grooves from the lower case seats 43 or provide them to the 
seats 43' of the upper case B, too. 
As mentioned above, the branch connection busbars each consist of a busbar 
strip and a plurality of branched tabs which are formed on the upper and 
lower lateral edges of the busbar in such a way that the upper and lower 
branched tabs are staggered. The upper and lower cases that accommodate 
these branch connection busbars are provided at the outer surfaces with 
connector insertion portions at positions that correspond to the groups of 
branched tabs. This construction not only makes the branch junction box 
compact but also allows an increased number of internal circuits to be 
formed in the junction box. 
Moreover, since the tab connecting portions of the branch connection 
busbars are firmly clamped and held between one case and the seats of 
another case, no trouble will occur such as the branched tabs becoming 
loose or dislocated. Particularly when the seats are formed with the 
insertion grooves for positioning the tab connecting portions, the 
branched tabs can be aligned with improved accuracy and the assembly work 
efficiency of the branch junction box can also be enhanced. 
In FIGS. 3a and 3b, the busbar 18.sub.1 has a series of identical two-pole 
tabs 2T, each of which consists of two tabs 19 projecting one on each side 
of the tab connecting portions 20 that are spaced at predetermined 
pitches. On the other hand, the busbar 18.sub.2 has a more complex 
structure in which there are from left to right, a three-pole tab 3T, a 
two-pole tab 2T and a five-pole tab 5T although the tab connecting 
portions 20, 21, 22 are spaced at the same pitches as in the first busbar 
18.sub.1. 
The above-mentioned branch connection busbars 18.sub.1, 18.sub.2, . . . 
have different branch patterns with differing shapes and numbers of 
branched tab poles and thus require their own special dies for punching. 
This not only increases the cost of dies and therefore the manufacturing 
cost but also requires preparing a new die when there is any change in the 
pattern. 
This problem can be solved by the use of a comb-shaped branch connection 
busbar C as shown in FIG. 11. The branch connection busbar C consists of a 
base strip 47 and a series of branched tabs 49 arranged like a comb 
integrally connected to one side of the base strip 47 through perforated 
portions 48, which are spaced from each other at specified pitches. 
Rising pieces 48a provided on each side of each perforated portion 48 
correspond to the rising pieces 20a of the tab connecting portions 20 in 
FIG. 3. A lateral strip 48b provided at the top of the perforated portions 
48 corresponds to the tab connecting pieces 20b connected in line. 
This branch connection busbar C can be formed by punching a conductive 
metal plate made of such materials as brass, beryllium and copper with a 
single die. 
With this branch connection busbar C, a busbar which has the same 
construction as the busbar 18.sub.2 of FIG. 3b can be manufactured by 
partially cutting off those branched tabs 49 shaded as S.sub.1 in FIG. 12, 
those rising pieces 48a and/or lateral strip 48b of the perforated 
portions 48 shaded as S.sub.2, and those portions of the base strip 47 
shaded as S.sub.3. 
Appropriately selecting the cutting positions on the base strip 47, 
perforated portions 48 and branched tabs 49 forms a busbar with any 
desired branch pattern. The punching operation can be carried out with a 
single die, substantially reducing the manufacturing cost. 
FIG. 13 shows another example of branch connection busbar C' with laterally 
elongate perforated portions 48', which are formed by removing every other 
rising piece 48a of the perforated portions 48 in FIG. 11. 
In this way, the pitches of the perforated portions 48 or 48' and of the 
branched tabs 49 as well as other dimensions can be determined 
arbitrarily. 
With the perforated portions 44' formed laterally elongate as shown in FIG. 
13, it is possible to reduce the number of cut-off positions and cutting 
operations in making the branch connection busbar. 
As mentioned above, it is possible to form a number of branch connection 
busbars with various branch patterns from the comb-shaped branch 
connection busbars with one and the same branch pattern, reducing the cost 
of die and therefore the cost of manufacture. The comb-shaped branch 
connection busbar also permits an easy and swift change to be made in the 
branch pattern.