Electrical connectors – Contact comprising cutter – Insulation cutter
Reexamination Certificate
2002-07-12
2004-06-15
Paumen, Gary F (Department: 2833)
Electrical connectors
Contact comprising cutter
Insulation cutter
C439S877000, C439S882000
Reexamination Certificate
active
06749457
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a crimp terminal for connecting electric wires by crimping, and more particularly to an improvement of conductor engaging grooves (serrations) which are formed on an inner face of a bottom plate part, etc. of the terminal, and advantageously contribute to an improvement of electrical connecting performance as well as an improvement of mechanical connecting performance between the terminal and conductors of the electric wires.
FIGS. 6 and 7
show examples of related-art crimp terminals.
A crimp terminal
1
as shown in
FIG. 6
is the crimp terminal for screw fitting, and includes a terminal portion
2
for screw fitting which has a screw insertion hole
2
a
formed at its distal end, a conductor crimping portion
4
and a sheath crimping portion
5
which are provided in order behind the terminal portion
2
. These portions are integrally formed of a sheet of metal plate by stamping process.
The conductor crimping portion
4
is a portion for connecting bare conductors
7
b
by crimping, which are exposed by removing an insulation sheath
7
a
from a sheathed electric wire
7
, as also shown in FIG.
8
. The conductor crimping portion
4
has a bottom plate part
4
a
on which the bare conductors
7
b
are placed, and a pair of crimp claws
4
b
which are adapted to be crimped onto the bare conductors
7
b
placed on this bottom plate part
4
a
, by a crimping equipment
9
(See FIG.
9
).
The sheath crimping portion
5
is a portion for crimping the sheathed electric wire
7
to fix it together with the insulation sheath
7
a
, and includes a bottom plate part
5
a
on which the sheathed electric wire
7
is placed, and a pair of crimp claws
5
b
which are crimped onto the sheathed electric wire
7
placed on the bottom plate part
5
a
, by the crimping equipment
9
(See FIG.
9
).
The crimping equipment
9
is a kind of pressing apparatus which includes, as shown in
FIGS. 9 and 10
, an anvil
9
a
for supporting the bottom plate parts
4
a
,
5
a
of the conductor crimping portion
4
and the sheath crimping portion
5
, and two crimpers
9
b
,
9
c
provided above the anvil
9
a
so as to move up and down for respectively crimping the crimp claws
4
b
and the crimp claws
5
b.
Meanwhile, a crimp terminal
11
as shown in
FIG. 7
, is a relaying crimp terminal for connecting conductors of a plurality of sheathed electric wires
12
a
,
12
b
,
12
c
together in a bundle, and has a bottom plate part
11
a
on which a plurality of bare conductors
13
are placed, and a pair of crimp claws
11
b
which are extended from both sides of the bottom plate part
11
a
and adapted to be crimped onto the bare conductors
13
placed on the bottom plate part
11
a
, by a crimping equipment. The bottom plate part
11
a
and the crimp claws
11
b
are integrally formed of a sheet of metal plate by stamping process.
It has been known that in order to enhance electrical connecting performance and mechanical connecting performance between the bare conductors and the bottom plate parts of these crimp terminals, a plurality of conductor engaging grooves
17
in a concave shape (hereinafter referred to as “serrations”) extending in a direction intersecting axes of the bare conductors (usually, in a perpendicular direction) are provided on an inner face
16
of the bottom plate part, etc. of the terminal to be contacted with the bare conductors, as shown in
FIGS. 11 and 12
.
In this case, all the serrations have a groove width and a groove depth of the same size, and are in the same shape.
When the crimp claws
4
b
,
11
b
have been crimped, groove edges of the serrations
17
are intensively pressed so as to adequately bite the bare conductors
7
b
,
13
on the surface, and both the mechanical connecting performance and the electrical connecting performance can be improved, ensuring reliability of the connection by crimping.
By the way, in order that oxidized coatings formed by oxidation on the surfaces of the conductors may be removed when the edges of the serrations
17
have bitten the bare conductors
7
b
,
13
by the edges, it is necessary for the serrations
17
to be set to have a large amount of bite, and it is necessary to make the serrations
17
deep for an increase of the amount of bite.
On the other hand, in case where the serrations have been set to have a large amount of bite, stresses will be converged on crimped areas of the conductors when a tensile force is exerted on the bare conductors
7
b
,
13
from outside. As the results, the bare conductors
7
b
,
13
will be likely to be broken, resulting in deterioration of the mechanical connecting performance.
Under the circumstances, in order that improvements of the electrical connecting performance and the mechanical connecting performance may be obtained while keeping their balance, the depth of the serrations
17
and crimping amounts of the crimp claws can be determined in consideration of outer diameters of the bare conductors.
However, there have been many cases in which the crimp terminals employed in a wire harness or the like for a motor vehicle must connect the sheathed electric wires having various diameters, or must crimp the conductors having different outer diameters together in a bundle.
For this reason, it is extremely difficult to determine the depth of the serrations
17
and the crimping amounts of the crimp claws so that improvements of both the electrical connecting performance and the mechanical connecting performance can be obtained while keeping their balance. For example, in case where a plurality of the bare conductors having different outer diameters have been crimped together in a bundle, even though the large diametered bare conductors may be improved both in the electrical connecting performance and the mechanical connecting performance, the small diametered bare conductors may be too much engaged by the serrations
17
, resulting in a probability that even a slight tensile force may break the bare conductors.
Moreover, in case where the mechanical connecting performance is intended to be ensured, by setting the depth of the serrations
17
according to the bare conductor having the smallest diameter among the bare conductors
7
b
,
13
to be crimped, there has been such an anxiety that in the bare conductors having the larger diameters, the edges of the grooves cannot sufficiently remove the oxidized coatings on the surfaces of the conductors, incurring defective electrical connecting performance.
In order to eliminate such disadvantages contradicting each other, a crimp terminal
21
as shown in
FIGS. 13 and 14
has been proposed.
This crimp terminal
21
is disclosed in Japanese Patent Publication No. JP 59-165390A, and includes two conductor crimping portions
23
,
24
having different crimping amounts. The conductor crimping portion
23
positioned at a proximal end side of the bare conductors forms a crimping part having a small amount of bite of the serrations with respect to the conductors, by adjusting a height of the crimp claws
23
b
,
23
b
and controlling a crimper
26
b
in a crimping equipment
26
so as to obtain a smaller crimping amount.
On the other hand, the conductor crimping portion
24
which is positioned at a distal end side of the bare conductors forms a crimping part having a large amount of bite of the serrations with respect to the conductors, by adjusting a height of the crimp claws
24
b
,
24
b
and controlling a crimper
26
c
in the crimping equipment
26
so as to obtain a larger crimping amount.
In this manner, by providing two types of the conductor crimping portions
23
,
24
having different crimping amounts, incomplete or excessive amount of bite by the serrations has been eliminated, even in case where the bare conductors having small diameters and large diameters are mixed, and both the electrical connecting performance and the mechanical connecting performance have been able to be improved.
However, in the crimp terminal
21
as shown in
FIGS. 13 and 14
, an increase in number of t
Maki Toshihiro
Sakaguchi Tadahisa
Paumen Gary F
Sughrue & Mion, PLLC
Yazaki -Corporation
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