Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-07-14
2002-05-14
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S800000, C361S730000, C174S254000, C200S292000, C439S077000, C439S067000
Reexamination Certificate
active
06388883
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a lead out structure for a lead circuit section connected to a flexible printed circuitry housed in a casing of a switch unit.
Door trims for vehicles such as automobiles are normally provided with electrical equipment such as a switch unit including power window switches for use in opening and closing window glasses, door mirror driving switches and so on; and courtesy lamps that are switched off when doors are shut and switched on when opened. In order to connect these kinds of electrical equipment, the door trim is rigged with a number of electric wires and connectors. Such wiring operation is very troublesome because it is carried out blindly through the working window of a door panel. Moreover, many parts for use in electrical mechanism-to mechanism connection are required, which will also result in arduous work of incorporating and connecting them.
In consequence, there has recently been employed a flat circuitry for wiring to complete the connection of electrical equipment (e.g., Japanese Patent Publication No. 9-309390A). A switch holder
1
in a related flat circuitry has been so configured as shown in FIG.
4
.
In
FIG. 4
, the upper-side terminal section
3
of a flexible printed circuitry
2
is bent at a right angle and inserted into and fixed to a switch holder
1
. The flexible printed circuitry
2
includes a plastic insulating film
4
and a plurality of parallel printed circuits
5
arranged in the insulating film
4
. Further, an engagement hole
6
is bored in four corners of the insulating film
4
and a plurality of contacts
7
following the respective printed circuits
5
are provided in the upper-side terminal section
3
of the flexible printed circuitry
2
.
The plastic switch holder
1
comprises a rectangular base plate
8
and a frame-like cover
9
that is pivotal with respect to the base plate
8
. The cover
9
is coupled to the base plate
8
by, for example, thin-walled hinges that are integral therewith. A frame wall
10
is uprightly provided to both sides of the base plate
8
. Further, an elastic retaining arm
12
and a curved elastic flap
13
with respect to a door trim
11
are projected from the outer wall face of each frame wall
10
. In other words, the elastic retaining arm
12
is provided on the rear end portion of each frame wall
10
, whereas the elastic flap
13
is provided on the front end portion thereof. Each elastic retaining arm
12
has a retaining projection
14
and a releasing member
15
. Moreover, engagement holes
17
with respect to the locking projections
16
provided to the cover
9
are formed in the frame wall
10
.
Positioning pins
19
each having conical tilted guide faces
18
relative to the respective retaining holes
6
of the flexible printed circuitry
2
are projected from the base plate
8
. Further, an opening
20
is provided in the cover
9
, so that the contacts
7
of the flexible printed circuitry
2
and the positioning pins
19
can be located within the opening
20
. Incidentally, the tilted guide face
18
may be continuous from the upper to lower ends of the positioning pin
19
.
The terminal section
3
of the flexible printed circuitry
2
is positionally mounted on the base plate
8
by mating the engagement holes
6
with the respective positioning pins
19
. Then the locking projections
16
are fitted in the respective engagement holes
17
by closing the cover
9
, which is locked in such a condition that it clamps the terminal section
3
. The positioning pins
19
are so positioned as to project within the opening
20
. Due to the positioning pins
19
, the contacts
7
are precisely positioned.
FIG. 5
shows a state wherein a flat circuitry
21
has been incorporated in the door trim
11
. More specifically, an opening
22
is formed in the door trim
11
, and a pair of insertion guides
23
with respect to the switch holder
1
of the flat circuitry
21
. are provided in the direction of thickness of the door trim
11
. The insertion guides
23
are L-shaped and projected from the upper wall
24
within the opening
22
. Moreover, an engagement hole (not shown) is formed in each insertion guide
23
with respect to the retaining projection
14
of the elastic retaining arm
12
of the switch holder
1
. The switch holder
1
is supported by the elastic retaining arms
12
and the elastic flaps
13
between the pair of insertion guides
22
so as to be movable in the widthwise direction thereof.
The flexible printed circuitry
2
is made immovable by fitting the positioning pins
19
in the engagement holes
6
respectively provided in the four corners of the insulating film
4
and holding down the flexible printed circuitry.
2
with the cover
9
.
The flexible printed circuitry
2
is prepared by printing switching circuits on the film to form an extremely thin contact switch. Although the flexible printed circuitry
2
is immovably fixed by fitting the positioning pins
19
in the respective engagement holes
6
and made immovable by holding it down with the cover
9
, the film-like lead circuit section is drawn from the switching circuit section. Consequently, the film-like lead circuit section is strong enough to withstand the tensile force applied in its longitudinal direction. When force is applied in a direction perpendicular to the longitudinal direction of the film-like lead circuit section (in its widthwise direction), however, excessive force as tensile stress is to be applied to one side portion of the circuit section.
When the tensile stress is applied from the outside to the flexible printed circuitry
2
like this, the operating switches may not easily be turned on as the switch contacts become displaced. When further excessive tensile stress is applied from the outside to the flexible printed circuitry
2
, the problem is that the disconnection of switching circuits occurs.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention is provide a structure wherein a switching circuitry is formed integrally with a lead circuitry whereby to prevent stress from being applied to the switching circuitry even when tensile stress is applied to the lead circuitry while the lead circuitry is being wired and conveyed, to prevent the switching circuitry from being displaced even when excessive stress acts on the lead circuitry; and to prevent the lead circuitry from being broken even when excessive stress acts on the lead circuitry.
In order to accomplish the object above, according to the present invention, there is provided a structure comprising:
a flexible printed circuitry including a lead circuit section integrally provided with a switch circuit section, and at least one engagement hole is formed on a part of the lead circuit section;
a lower casing having a side wall provided with a cut out portion from which the lead circuit section is led out, and at least one boss formed in the form of S-shape, to which the engagement hole is fitted to mount the flexible printed circuitry thereon; and
an upper casing combined with the lower casing to constitute a casing which serves as a switch circuit unit, the upper casing having at least one hold-down member engaged with the boss to hold down the lead circuit section onto the lower casing.
Since the switching circuitry is formed integrally with the lead circuitry whereby it is possible to prevent stress from being applied to the switching circuitry even when tensile stress is applied to the lead circuitry while the lead circuitry is being wired and conveyed; to prevent the switching circuitry from being displaced even when excessive stress acts on the lead circuitry; and to prevent the lead circuitry from being broken even when further excessive stress acts on the lead circuitry.
Preferably, at least three engagement holes are formed on the lead circuit section so as to be arranged in a longitudinal direction thereof with predetermined intervals. The lead circuit section is folded such that all the engagement holes are fitted with the boss to be m
Kubota Minoru
Serizawa Yasuyoshi
Bui Hung
Gandhi Jayprakash N.
Morgan & Lewis & Bockius, LLP
Yazaki -Corporation
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