Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Utility Patent
1999-07-20
2001-01-02
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
C029S865000, C029S866000, C439S849000, C439S850000
Utility Patent
active
06169961
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method and an apparatus for producing an insulation displacement terminal which is designed to perform a given characteristic and to the insulation displacement terminal produced by the method.
For convenience of explanation, a conventional insulation displacement terminal and a method for producing the same will be described below by referring to
FIGS. 11
to
14
.
FIG. 11
is an explanatory view illustrating a method for producing a conventional insulation displacement terminal.
FIG. 12
is a graph illustrating a relationship between a height of conductive wires and a compressive force in the case of producing the insulation displacement terminal by the method shown in FIG.
11
.
FIGS. 13A through 13C
are explanatory views illustrating a change of arrangement of the conductive wires in association with compression in the case where the conductive wires of the insulation sheath cable comprise twisted wires.
FIG. 14
is a front elevational view of a conventional insulation displacement terminal produced by the method shown in FIG.
11
.
In general, an insulation displacement terminal
1
includes an insulation displacement blade
2
provided with a slot
3
, as shown in FIG.
14
. When an insulation sheath electrical cable
6
is inserted into the slot
3
from a distal end (upper end in
FIG. 14
) of the slot, conductive wires
7
(
FIGS. 13A
to
13
C) come into press contact with the blade
2
while an insulation sheath
8
of the cable
6
(
FIG. 11
) is being cut by the blade
2
, thereby completing an electrical connection between the cable
6
and the terminal
1
. It has been required to set a characteristic of an insulation displacement in compliance with a kind of cable
6
being connected so as to obtain a good insulation displacement connection.
FIG. 11
shows a conventional method for designing the insulation displacement terminal
1
which will satisfy such a requirement.
The method of designing the insulation displacement terminal
1
will be explained below.
First, the insulation sheath
8
of the electrical cable
6
is removed over a predetermined area to expose the conductive wires
7
. Secondly, as shown in
FIG. 11
, a pair of probes
51
and
52
clamp the conductive wires
7
from which the insulation sheath
8
is removed. A compressive load and a height of the conductive wires are measured by changing a compressive load on the wires
7
exerted by the probe
52
, as shown by an arrow. Then, in the case where the conductive wires
7
are made of a plurality of twisted wires (for example, seven twisted wires) a relationship between the compressive load and the height of the conductive wires is shown by lines
61
a
and
61
b
in FIG.
12
. That is, when the twisted conductive wires
7
are subject to the compressive load, an arrangement of the wires
7
is changed, as shown in
FIGS. 13A
to
13
C. The compressive load will alter irregularly to a point P in
FIG. 12
during compression of the conductive wires
7
(a decrease of the height of the wires). When the conductive wires
7
are compressed over the point
7
, however, the load rises abruptly (line
61
b
) since the twisted conductive wires
7
are compacted into a unit and behave as a single wire.
Accordingly, it is preferable to determine an initial slot width A
1
of the insulation displacement terminal, a terminal displacement amount B
1
after being brought into an insulation displacement at a predetermined press contact position, a slot width after being brought into the insulation displacement, and a reaction force corresponding to the terminal displacement amount B
1
so that the insulation displacement will occur in an area within a point Q in
FIG. 12
on which the load rises up abruptly. That is, a beam width, a thickness and a slot length of the insulation displacement terminal
1
are designed so that a curve line
62
, which illustrates a relationship between a displacement and a reaction force which are caused by an elastical deformation from the initial slot width A
1
, will pass through the point Q.
However, since the electrical cable
6
is inserted into the slot
3
in the U-shapted insulation displacement terminal
1
shown in
FIG. 14
from an upper part of the slot upon an actual insulation displacement, the electrical cable
6
also receives a force in an inserting direction. The conductive wires
7
cause arrangements different from those in the case where the wires are merely compressed from the upper part, as shown in FIG.
11
. In addition, in actual insulation displacement, the insulation sheath
8
of the electrical cable
6
is cut by the slot at the initial stage of the insulation displacement, and thus this cutting condition is greatly different from the condition of predeterminately removing the insulation sheath over a given area in the manner shown in FIG.
11
.
Accordingly, it is difficult in the manner shown in
FIG. 11
to make an accurate estimate of an actual characteristic of connection. Assuming that an initial slot width, a terminal displacement amount, and a slot width after connection in an actual insulation displacement terminal are A
2
, B
2
and C
2
, respectively, B
2
and C
2
are deviated from B
1
and C
1
shown in FIG.
12
. Consequently, the actual terminal is inclined to be put on a condition different from designed values.
This inclination becomes more significant as a size of the conductive wires becomes smaller. This is a serious problem upon reducing a diameter of the electrical cable and compacting a portion of the insulation displacement in association with producing more compact devices.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a method for producing an insulation displacement terminal which can precisely realize an expected performance at a design time and provide a suitable insulation displacement connection by carrying out a design in accordance with data measured under conditions similar to an actual insulation displacement connection.
A second object of the present invention is to provide an apparatus for producing an insulation displacement terminal which can precisely realize an expected performance at a design time and provide a suitable insulation displacement connection by carrying out a design in accordance with data measured under conditions similar to an actual insulation displacement connection.
A third object of the present invention is to provide an insulation displacement terminal which can precisely realize an expected performance at a designing time and provide a suitable insulation displacement connection by carrying out a design in accordance with data measured under conditions similar to an actual insulation displacement connection.
In order to achieve the first object, a method for producing an insulation displacement terminal, in accordance with the present invention, which has an insulation displacement blade provided with a slot, in accordance with an insulation sheath electrical cable being worked, comprises the steps of: arranging a pair of metal blocks in parallel to each other so that the opposed side edges of the blocks can be resiliently spaced apart from each other, each metal block having a tapered portion at an end of the side edge; measuring an extent of insertion of the cable, a distance between the spaced metal blocks, a reaction force acting between the cable and the spaced metal blocks and a contact resistance acting between the cable and the spaced metal blocks while inserting the cable into a gap between the spaced metal blocks from the side of the tapered portions;
extracting data of an extent of the insertion, a spaced distance, a reaction force, and a contact resistance after completing the insertion out of data measured from the time when the insertion of the cable started to the time when the contact resistance is settled at the lowest level;
judging whether or not conductive wires of the cable are broken;
repeating the steps of the cable insertion, measurement, data extraction, and judgment
Bierman, Muserlian and Lucas
Bui Bryan
Hoff Marc S.
Sumitomo Wiring Systems Ltd.
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