Electrical connectors – Contact comprising cutter – Insulation cutter
Reexamination Certificate
2000-04-11
2001-09-04
Sircus, Brian (Department: 2839)
Electrical connectors
Contact comprising cutter
Insulation cutter
Reexamination Certificate
active
06283784
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a press-contact terminal fitting, and more specifically, the present invention relates to a structure of a press-contact terminal fitting comprising a press-contact section for press-fitting an end portion of a sheathed electric wire and holding strips for crimping the sheathed electric wire.
As one of press-contact terminal fittings of this type, a press-contact terminal fitting
3
, as shown in
FIG. 5
, to be disposed in the housing
2
of the connector
1
to be connected to a circuit board (printed board) has been used.
FIG. 6
is a cross sectional view taken along the line B—B of FIG.
5
. The connector
1
is, as shown in the
FIG. 5
, disposed and fixed on the wiring board (printed board)
4
. The connector
1
is provided with insertion legs
1
A projecting from the bottom thereof for securing it to the wiring board
4
(refer to FIG.
6
). In the housing
2
of the connector
1
, there are provided a plurality of open-top chambers
2
A for accommodating the sheathed electric wires
5
arranged in parallel. On one of side walls
2
B of the housing
2
, as shown in
FIG. 5
, there are provided openings
2
C in communication with respective chambers
2
A for leading out the sheathed electric wires
5
.
The press-contact terminal fitting
3
is, as shown in
FIG. 7
, formed by punching and bending a metal plate, and provided with a press-contact section
6
for electrically press-contacting with the sheathed electric wire
5
and a holding section
7
for surrounding and holding the sheathed electric wire
5
. Depicted by a reference numeral
8
in
FIG. 7
is a connecting strip which projects downwardly when the terminal fitting is accommodated in the connector
1
.
The press-contact section
6
of the press-contact terminal fitting
3
comprises, as shown in FIG.
7
and
FIG. 8
, a pair of opposed clamping plates
6
A and
6
B standing upwardly from both sides of the press-contact terminal fitting
3
for clamping the wire. The clamping plates
6
A and
6
B respectively include two each of press-contact blades
6
C and
6
D, which are bent inwardly so as to project toward each other. In this press-contact section
6
, the sheathed electric wire
5
is press-fitted from above as shown in
FIG. 8A
, and the resin sheath
5
A of the sheathed electric wire
5
is cut by the press contact blades
6
C and
6
D so that the press contact blades
6
C and
6
D are directly connected to the core conductive wire
5
B of the sheathed electric wire
5
.
The holding section
7
is composed of a pair of holding strips
7
A and
7
B standing upwardly from both sides of the press-contact terminal fitting
3
. In order to hold the sheathed electric wire
5
with the holding section
7
, as shown in
FIG. 9A
, the sheathed electric wire
5
is placed between the holding strips
7
A and
7
B and crimped by the use of a jig (punch) as shown in FIG.
9
B. As a result, as shown in
FIG. 9B
, a pair of holding strips
7
A and
7
B are in press-contact with the resin sheath
5
A to hold the sheathed electric wire
5
.
The press-contact section
6
and the holding section
7
disposed behind thereof are connected by rectangular shaped connecting plates
3
A shown by a hatched area in FIG.
7
. The connecting plates
3
A effect to reinforce and prevent the clamping plates
6
A and
6
B from being urged outwardly when the sheathed electric wire
5
is press-fitted between the clamping plates
6
A and
6
B.
However, when the related press-contact terminal fitting
3
is used to connect and hold the sheathed electric wire
5
, the following problem is encountered.
After the sheathed electric wire
5
is press-fitted into the press-contact section
6
and an electrical connection of established, when the holding strips
7
A and
7
B on the holding section
7
are crimped as shown in
FIG. 9B
, a force to urge the clamping plates
6
A and
6
B in the direction shown by the arrow a is exerted in conjunction with the bending operation of the holding strips
7
A and
7
B. Therefore, the press-contact blades
6
C and
6
D may move closer with respect to each other and may cut off the core conductive wire
5
B of the sheathed electric wire
5
. On the contrary, in the case where the sheathed electric wire
5
is press-fitted into the press-contact section
6
after the sheathed electric wire
5
is held by bending the holding strips
7
A and
7
B, the core conductive wire
5
B may be cut off because the distance between the press-contact blades
6
C and
6
D is decreased.
SUMMARY OF THE INVENTION
Therefore, the object of the invention is to find a measure to provide a press-contact terminal fitting which ensures the electrical connection without cutting off the core conductive wire of the sheathed electric wire when the sheathed electric wire is press-fitted and held.
In order to achieve the above object, according to the present invention, there is provided a press-contact terminal fitting comprising:
a pair of opposed clamping plates between which a sheathed electric wire is to be fitted;
a press-contact blade formed inside of the respective clamping plates for cutting a sheath of the sheathed electric wire to electrically connecting with a conductive wire thereof when the sheathed electric wire is fitted between the clamping plates;
a pair of holding strips which are to be bent to hold the sheathed electric wire fitted between the clamping plates; and
a pair of connecting plates for integrally connecting the clamping plate and the holding strip, respectively,
wherein a dimension of a portion where the connecting plate is connected to the clamping plate is shorter than a dimension of a portion where the connecting plate is connected to the holding strip.
Accordingly, when the holding strips are bent to hold the sheathed electric wire placed between the clamping plates, the tendency of a tensile stress caused by the bending action to be transmitted to the clamping plates will be reduced at the portion where the dimension of the connecting plate is short in height. In other words, the tendency of the moment applied to the holding strips in the direction of bending to cause a tensile stress to be transmitted will be reduced because the dimension of the connecting plate on the side of clamping plate is short in height. Therefore, it may prevent the press-contact blades formed on the opposed surfaces of the clamping plates from getting closer, and thus prevent the core conductive wire of the sheathed electric wire from being cut. A press-contact terminal fitting with a high degree of reliability can be realized at a low cost.
Preferably, The pair of holding strips includes a first holding strip and a second holding strip which is arranged closer to the associated clamping plate than the first holding strip. Here, a dimension of a portion where the connecting plate associated with the second holding strip is connected to the clamping plate is shorter than a dimension of a portion where the connecting plate associated with the first holding strip is connected to the clamping plate.
Accordingly, since the positions of the holding strips in the longitudinal direction are displaced with respect to each other, sufficient length of holding strips for holding the sheathed electric wire can be obtained securely to improve the durability of the connection of the wire. In addition, there can be prevented a tensile stress caused by the action to bend the holding strips from being transmitted to the side of the clamping plates which may result in cutting off of the core conductive wire of the sheathed electric wire.
Preferably, the clamping plates and the holding strips are to be accommodated in a connector housing made of an insulating material.
Accordingly, since the connecting plates prevent the clamping plate from being widened (fell down) outwardly, inner walls of a chamber of the connector housing for accommodating the terminal fitting may not damaged.
REFERENCES:
patent: 6007365 (1999-12-01), Atsumi et al.
patent: 6019626 (2000-02-01), Abe
patent: 60
Morgan & Lewis & Bockius, LLP
Sircus Brian
Webb Brian S.
Yazaki -Corporation
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