Apparatus and method for laying a wire

To provide wire laying method and apparatus which realize high utilization of a wire laying space by pressing a plurality of wires one over another in a wire groove formed in an insulating plate, wires 2A to 2C drawn from a wire laying head 5 are, while being inserted into a wire groove 1a using a natural bend R, forcibly pressed to specified depths by a pressing pin 11 in synchronism with the movement of the wire laying head 5.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an electrical connection box for 
automotive vehicles and is particularly designed to highly utilize a wire 
laying space by inserting a plurality of wires one over another into a 
wire groove formed in an insulating plate mounted in a casing of the 
electrical connection box. 
2. Description of the Prior Art 
Among the electrical connection boxes of this type, there is known one for 
easily responding to a design change of the internal circuits, in which 
box wires are arranged instead of the use of a busbar formed by punching a 
conductive metal plate, and the connection between the wires and external 
input/output terminals and the connection between the wires are 
established by the use of cramping terminals. 
The above wires are laid as follows. After being laid in a wiring mold 
formed with a wire groove having the same pattern as a wiring pattern, the 
wires are transferred to a casing or an insulating plate on which cramping 
terminals are already mounted so that the wires are cramped by the 
cramping terminals at the same time when they are laid. 
Instead of the method which employs the wiring mold, the present applicant 
previously proposed a method for laying wires directly along the wire 
groove formed in the insulating plate. 
When using this prior art approach, a wire 2 is to be laid along a wire 
groove formed in a mold or a wire groove 1a formed in an insulating plate 
1 as shown in FIG. 7(A), the wire 2 is laid into the groove 1a as shown in 
FIG. 7(B). 
In accordance with the prior art method, and as shown in FIG. 5, the wire 2 
is laid as follows. The wire 2 drawn from a path 3a of a wire laying head 
3 which moves in one direction along the upper surface of the insulating 
plate 1 is laid while being arranged in the wire groove 1a using a natural 
bend R. 
As seen in FIG. 7(B), it is difficult to arrange the wire 2 into the groove 
1a at a corner portion 1c of the groove 1a using only the natural bend R. 
Thus, a recess 1d for allowing the wire 2 to bend is formed in the corner 
portion 1c. By bending the wire 2 in the recess 1d as shown in FIG. 7(C), 
the wire 2 can be arranged into the corner portion 1c as shown in FIG. 
7(D). 
However, since the prior art wire laying method is such that the wire 2 is 
arranged into the groove 1a using the natural bend R, the wire 2 cannot be 
deeply inserted into the groove 1a as shown in FIG. 6(A). 
Accordingly, even if an attempt is made to insert another wire 2B over a 
previously inserted wire 2A in order to reduce a space taken up by the 
laid wires, the wire 2B is likely to come out of the groove 1a because the 
previous wire 2A is not sufficiently deeply inserted. Thus, a plurality of 
wires 2A and 2B cannot be securely laid one over another. 
If another wire groove 1e for the wire 2B is formed inward of the groove 1a 
for the wire 2A, the wires 2A and 2B can be laid next to each other in the 
horizontal direction, as shown in FIG. 6B. However, this leaves a problem 
due to the larger wire laying space needed. 
Thus, it is an object of the present invention to provide wire laying 
method and apparatus for deeply inserting a wire into a groove, in 
particular, for realizing a high utilization of a wire laying space, when 
a plurality of wires have to be arranged. 
SUMMARY OF THE INVENTION 
According to the subject invention, wire drawn from a wire laying head is 
inserted into a wire groove using a natural bend, and is forcibly pressed 
to a specified depth in the vicinity of the end of this bent portion by a 
pressing means. 
Accordingly, the wire can be forcibly pressed to the specified depth even 
in the portions where it is difficult to press the wire only using the 
natural bend, particularly a corner portion and a linear portion having a 
narrow width. Further, since the wire extending substantially in the 
horizontal direction in the vicinity of the bent portion is pressed down 
by the pressing means, in particular by a pressing pin, the sheath of the 
wire will not be damaged by the friction between the wire and the pressing 
pin. 
According to a preferred embodiment of the invention, the wire laying head 
is provided with pressing means, preferably with a pressing pin, which 
moves upward and downward in synchronism with the movement of the wire 
laying head. Thus, the height of the pressing pin can be easily 
controlled. 
Preferably, the method for laying a wire in an electrical connection box is 
performed by pressingly inserting a wire drawn from a wire laying head 
into a wire groove formed in a wire laying member inclined to the wire 
groove while naturally bending the wire by its contact with the bottom 
surface of the wire groove, wherein the wire being inserted into the wire 
groove while being bent is inserted into the wire groove while being 
forcibly pressed down to a specified depth by a pressing pin movably 
mounted in the vertical direction on the wire laying head. 
Preferably, when a plurality of wires are laid one over another in the wire 
groove, the height of the pressing pin is controlled in such a manner that 
the pressing pin is lowered to a predetermined position when the lower 
wire is laid, while being raised to another predetermined position when 
the upper wire is laid. 
Accordingly, the height of the pressing pin is controlled to control the 
depth by which the wire is inserted into the wire groove. Thus, the wires 
can be laid in a highly compact manner by inserting the wires one over 
another in the wire groove. 
Preferably, the wire laying member comprises an insulating plate mounted in 
a casing of the electrical connection box, and wherein the wire(s) is/are 
laid while being pressing into the wire groove formed at least in one 
surface of the insulating plate in conformity with a circuit pattern. 
Accordingly, the wire is directly laid in the wire groove formed in the 
insulating plate. Thus, an operation process can be simplified compared to 
the prior art method according to which the wire is transferred to the 
insulating plate or casing after being laid in the wiring mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Elements having the same construction and action as the prior art as shown 
in FIGS. 5 to 7(D) are identified by the same reference numerals and no 
detailed description is given thereto. 
As shown in FIGS. 1 and 2, a head main body 6 is mounted at the lower part 
of a wire laying head 5 movably upward and downward. A wire retaining arm 
7 facing the upper surface of an insulating plate 1 formed with a wire 
groove 1a is mounted on the main body 6 movably upward and downward. 
The head 5 is provided with guide rollers 8, 8 and a feed roller 9 for 
guiding and feeding a wire 2, respectively. As indicated by arrows in FIG. 
2, the wire 2 is drawn from the retaining arm 7 at a specified speed as 
the feed roller 9 rotates. 
The head main body 6 is stroke-controlled such that it moves upward and 
downward relative to the head 5 at specified strokes. 
The retaining arm 7 is movably guided in the vertical direction by a guide 
member 6a of the head main body 6, and is biased downward by a spring 10 
mounted between a projection 6b of the head main body 6 and an upper end 
of the retaining arm 7. 
While the wire 2 is laid, the lower edge or end of a wire drawing path 7a 
of the retaining arm 7 is constantly in contact with the upper surface of 
the insulating plate 1 due to the biasing force of the spring 10. 
A pressing pin 11 is inserted at the rear side (downstream side) of the 
wire drawing path 7a of the retaining arm 7 which is wide in a wire laying 
direction. The pressing pin 11 is secured on a bracket 12 projecting from 
the head main body 6. 
As shown in FIG. 3, wire 2 inserted from one lateral end of an inlet 7a-1 
at the upper end of the path 7a comes out from the other lateral end of an 
outlet 7a-2 at the lower end of the path 7 so that the wire 2 is inserted 
into the groove 1a inclined at a specified angle to the groove 1a. 
Since the retaining arm 7 is constantly in contact with the upper surface 
of the insulating plate 1 due to the biasing force of the spring 10 as 
described above, the pressing pin 11 secured on the head main body 6 via 
the bracket 12 moves downward in the wire drawing path 7a which is located 
in a fixed position. On the other hand, when the head main body 6 is moved 
upward, the pressing pin 11 moves upward in the wire drawing path 7a. 
The wire 2 passing through the wire drawing path 7a is drawn inclined 
between the inlet 7a-1 and the outlet 7a-2, and is inserted into the 
groove 1a inclined to the groove 1a. The inserted wire 2 comes into 
contact with the bottom surface of the groove 1a, thereby producing a 
natural bend R. 
The wire 2 is forcibly pressed down by the pressing pin 11 in the vicinity 
of an end of this natural bend R to be properly positioned. 
The height of the pressing pin 11 is controlled by controlling the downward 
stroke of the head main body 6. For example, in the case where three wires 
2A to 2C are pressed one over another into the groove 1a as shown in FIG. 
3(B), the stroke of the head main body 6 is first set such that the 
pressing pin 11 has a stroke S3 for pressing the wire 2A to a bottommost 
position; secondly such that the pressing pin 11 has a stroke S2 for 
pressing the wire 2B to a middle position; and finally such that the 
pressing pin 11 has a stroke S3 for pressing the wire 2C to an uppermost 
position. 
Further, when the head 5 undergoes a change of direction at a corner 
portion 1c of the groove 1a: from a moving direction A to a moving 
direction C which is at a right angle to the moving direction A as shown 
in FIG. 3(C), the pressing pin 11 is positioned at the corner portion 1c 
and the head 5 is rotated in a direction B about the pressing pin 11 as a 
center of rotation O. 
In order to press the three wires 2A to 2C one over another in the groove 
1a of the insulating plate 1 using the above constructed wire laying 
apparatus, the stroke of the pressing pin 11 is set to the stroke S1 
corresponding to the uppermost position and the head 5 is moved in the 
direction A as shown in FIGS. 3(C) and 4(A) so that the wire 2A drawn from 
the retaining arm 7 is pressed into the groove 1a using the natural bend 
R. 
At the corner portion 1c, the head 5 is rotated in the direction B about 
the pressing pin 11 as the center of rotation O as shown in FIG. 4(B). In 
synchronism with the rotation of the head 5, the pressing pin 11 is 
lowered to have the stroke S3, and the head 5 is moved further in the 
direction C. 
The portion of the wire 2A linearly laid in the direction A is pressed 
downward by the lowered pressing pin 11, which further presses the wire 2A 
to the bottommost position where the wire 2A is in contact with the bottom 
of the groove 1a so that the wire 2A drawn from the retaining arm 7 can be 
laid in the corner portion 1c and the linear portion 1b of the groove 1a 
extending in the direction C. 
Similarly, when the wire 2B is to be laid, the head main body 6 is moved 
upward so that the pressing pin 11 has the stroke S1. In this state, the 
wire 2B drawn from the retaining arm 7 is pressed into the groove 1a using 
the natural bend R while the head 5 is moved in the direction A. At the 
corner portion 1c, the pressing pin 11 is lowered to have the stroke S2 in 
synchronism with the rotation of the head 5 in the direction B. 
Accordingly, the portion of the wire 2B already laid in the direction A is 
pressed to the middle position, and the wire 2B is laid over the 
previously laid wire 2A in the bottommost position with the stroke S2 in 
the corner portion 1c and the linear portion 1b of the groove 1a extending 
in the direction C. 
Finally, when the wire 2C is laid in the uppermost position, the head main 
body 6 is moved upward so that the pressing pin 11 has the stroke S1. In 
this state, the wire 2C drawn from the retaining arm 7 is inserted into 
the groove 1a using the natural bend R while the head 5 is moved in the 
direction A. The wire 2C is forcibly pressed to the uppermost position at 
the end of the bent portion by the pressing pin 11. 
The wires corresponding to the bottommost, middle and uppermost positions 
are forcibly pressed to the specified depths in the groove 1a by the 
pressing pin 11 as described above. Accordingly, the wires 2A to 2C can be 
securely pressed to the specified depths even in the corner portion 1c and 
the narrow linear portions 1b where it is difficult to press the wires 
only using the natural bend R. 
Since the respective wires 2A to 2C do not come out of the groove 1a, they 
can be laid one over another in the groove 1a, thereby highly utilizing 
the wire laying space. 
Further, the wire is basically inserted into the groove using the natural 
bend, and the substantially horizontally extending wire is pressed 
downward by the pressing pin. Thus, problems such as a scraped sheath of 
the wire due to friction between the pressing pin 11 and the wire will not 
arise. 
Although the three wires 2A to 2C are laid one over another in the 
foregoing embodiment, one, two, four or more wires may be laid one over 
another. 
As is clear from the above description, the wire drawn from the wire laying 
head is inserted into the wire groove using the natural bend, and is 
forcibly pressed to a specified depth in the vicinity of the end of the 
bent portion by the pressing pin. The wire can be forcibly pressed to the 
specified depth even in the corner portion and the narrow linear portions 
where it is difficult to press the wires only using the natural bend. 
Preferably, the wires are pressed to the specified depths by controlling 
the distance by which the wires are pressed. Accordingly, the 
upper-located wire(s) can be pressed into the wire groove in such a manner 
that they do not come out of the wire groove. Thus, a plurality of wires 
can be laid one over another, thereby highly utilizing the wire laying 
space. 
Further, the wire laying head may be provided with the pressing pin which 
moves downward in synchronism with the movement of the wire laying head. 
Thus, the sheath of the wire will not be scraped due to the friction 
between the pressing pin and the wire being drawn, and the moving speed of 
the wire laying head is not slowed.