Electrical connectors – Contact comprising cutter – Insulation cutter
Reexamination Certificate
2001-01-05
2001-10-30
Sircus, Brian (Department: 2839)
Electrical connectors
Contact comprising cutter
Insulation cutter
Reexamination Certificate
active
06309241
ABSTRACT:
The present patent application claims the benefit of earlier Japanese Patent Applications Nos. 2000-017442 filed Jan. 26, 2000 and 2000-022177 filed Jan. 31, 2000, the disclosures of which are entirely incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a branch connection structure for a flexible circuit belt, such as a flexible flat cable (FFC) or a flexible printed circuit.
2. Description of the Related Art
In general, a branch connector is used to branch off a flexible circuit belt, such as a flexible flat cable (FCC), and to electrically connect the flexible circuit belt to two or more circuits. Such a branch connector is generally attached to the end of the flat cable. A counterpart connector that is attached to another circuit to be connected receives this branch connector of the flexible circuit belt, thereby making electrical connection between two or more circuits.
FIGS. 1 and 2
illustrate a conventional branch connector for use with a flexible circuit belt. This type of branch connector is disclosed in, for example, Japanese Patent Application Laid-open No. 4-359875.
As shown in
FIG. 1
, the conventional branch connector consists of one ore more connection terminals
1
. The connection terminal
1
has a male contact
2
at the leading end, which is to be received by a female contact of a counterpart connector. The connection terminal
1
also has a tall fork
3
with a height H
1
and a shorter fork
4
with a height H
2
(H
2
<H
1
) near the trailing end.
FIGS. 1B and 1C
show how a set of connection terminals
1
are attached to the end of a flexible circuit belt, which consists of two flexible flat cables
5
and
6
. The connection terminals
1
are arranged in parallel to each other. A flexible flat cable
6
is superimposed on the FFC
5
so that the leading edge of the upper FFC
6
recedes from the leading edge of the FFC
6
by a prescribed distance. The forks
3
and
4
of each connection terminal
1
pierce through the superimposed flat cables
5
and
6
, and the tips of the forks
3
and
4
are folded back in order to tightly hold the flat cables
5
and
6
together. In this manner, electrical connection between the flat cables and the connection terminals
1
are guaranteed.
To be more precise, the lower layer flexible flat cable
5
is held by the shorter fork
4
, and the upper layer flexible flat cable
6
are held together with the FFC
5
by the taller fork
3
.
The lower flexible flat cable
5
comprises a conductive layer
7
and a pair of insulating films
9
sandwiching the conductive layer
7
, as shown in FIG.
1
C. The upper flexible flat cable
6
comprises a conductive layer
8
and a pair of insulating films
10
sandwiching the conductive layer
8
.
To complete a branch connection of the layered flat cables
5
and
6
(i.e., a flexible circuit belt) by the conventional connection terminals
1
, the shorter fork
4
first pierces the lower flat cable
5
. The tips of the fork
4
are bent using a piercing tool so that the tips stick into the conductive layer
7
of the lower flat cable
5
. The flexible flat cable
6
is superimposed over the flexible flat cable
5
with its leading edge receding from the leading edge of the lower flat cable
5
. At this time, the taller fork
3
pierces the upper flat cable
6
, as shown in FIG.
2
. The tips of the fork
3
are also bent using a piercing tool so that the tips stick into the conductive layer
8
of the upper flat cable
6
.
With the conventional connection terminal
1
, the piercing and bending steps have to be repeated twice. If three of more flat cables are piled, the same steps must be repeated as many times as the number of cable layers. The branch connection using the conventional connection terminals is time-consuming and requires much labor.
Another problem in the branch connection using the conventional connection terminal
1
is that the upper flexible flat cable
6
is stretched under a high tension when the branch connection assembly is applied to, for example, a wire harness device. A tensile stress is applied to the fork
3
, which is pressing the upper flat cable
6
for electric connection, when the wire harness device is installed in an automobile door. As a result, the fork
3
deforms, which may cause the contact resistance to increase.
SUMMARY OF THE INVENTION
The present invention was conceived in order to overcome these problems in the prior art technique, and it is an object of the invention to provide a branch connection structure for a flexible circuit belt, which has a high durability and can achieve a reliable electric connection.
To achieve the objects, a branch connection structure includes a flexible circuit belt, such as a flexible flat cable (FFC), and a plurality of connection terminals attached to the middle portion of the flexible circuit belt. The flexible circuit belt comprises a plurality of conductive strips arranged in parallel to each other at a predetermined interval, and a pair of insulating films sandwiching the conductive strips. One or more slits extend between any two adjacent conductive strips and along a middle portion of the conductive strip. The slits define a plurality of separated regions in the middle of the FFC, each region including one of the conductive strips.
Each of the connection terminals has conductive teeth and a pair of bendable retainers positioned on both sides of the conductive teeth. The conductive teeth pierce through the conductive strip of the associated separated region from the rear surface of the flexible circuit belt. The tips of the conductive teeth stick out of the top surface of the separated region, and are bent so as to pierce again into the conductive strip from the top surface of the separated region. The bendable retainers securely hold the separated region at both sides of the conductive teeth without touching the conductive strip. The flexible circuit belt is folded back at the connection terminals.
The bendable retainer has a pair of walls facing each other. The walls are fit into the slits extending on both sides of the associated separated region. The top ends of the walls are bent downward so as to press the top surface of the flexible circuit belt.
The conductive teeth also face each other. The gap between the opposing conductive teeth is narrower than the width of the conductive strip and than the gap between the facing walls of the bendable retainer. This arrangement allows the conductive teeth to pierce through the conductive strip without fail, and allows the retainer to hold the separated region without touching the conductive strip.
With this branch connection structure, electrical connection between the conductive teeth of the connection terminal and the conductive strip of the flexible circuit belt is guaranteed even if a tension is applied to the flexible circuit belt. Since the bendable retainers securely hold the separated region of the flexible belt at both sides of the conductive teeth, any tension or stress applied to the flexible circuit belt does not affect the mechanical connection between the conductive teeth and the conductive strip.
In another aspect of the invention, a branch connection structure that includes a flexible circuit belt (e.g., a flexible flat cable) folded in double and a plurality of connection terminals attached to the folded portion of the flexible circuit belt is provided. The flexible circuit belt comprises a plurality of conductive strips arranged in parallel to each other at a predetermined interval, an insulating film sandwiching the conductive strips. One or more slits extend between any two adjacent conductive strips and along a middle portion of the conductive strip, and the flexible circuit belt is folded in double at the middle of the slits. The slits define a plurality of doubled branch regions, each region including double conductive strip.
Each of the connection terminals has conductive teeth and a pair of bendable retainers positioned on both sides of the conductive te
Dinh Phuong K T
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Sircus Brian
Yazaki -Corporation
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