Geometrical instruments – Gauge – Collocating
Reexamination Certificate
1999-09-01
2001-10-30
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Gauge
Collocating
C033S701000
Reexamination Certificate
active
06308430
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of examining insulation displacement connection, for example, in the production of a wire harness, and also relates to an apparatus for performing this method.
2. Description of the Related Art
As shown in
FIG. 7
, a wire harness, for example, comprises parallel wires
50
each having a conductor
51
coated with an insulating resin
52
, connectors
30
connected to the wires
50
at suitable regions in a lengthwise direction and a widthwise direction, and covers
31
attached to the respective connectors
30
if necessary. In view of the efficiency of the operation, insulation displacement fitting connection (hereinafter referred to as “insulation displacement connection”) as shown in
FIG. 8
has now been increasingly used for connecting the wires
50
to the connector
30
.
As shown in
FIG. 8
, in this insulation displacement connection, a vertically-movable, insulation displacement connecting blade holder (not shown), having insulation displacement connecting blades
10
corresponding respectively to the wires
50
, is moved downward, and a distal end surface of each insulation displacement connecting blade
10
press-fits the associated wire
50
into slots
41
a
of an associated insulation displacement connecting terminal
40
of the connector
30
, so that the wire is held in the terminal
40
by pinching, produced in the terminal
40
at this time, and hence is connected to the terminal. During this press-fitting operation, the insulating sheath
52
is cut by inner edges of the slots
41
a
, so that the conductor
51
in the insulating sheath
52
is brought into contact with the inner edges of the slots
41
a
, thereby making an electrical connection between the conductor
51
and the insulation displacement connecting terminal
40
.
Examples of defective insulation displacement connection, developing during the above insulation displacement connecting operation, are as follows.
For some reason, if any of the wires, fed to the insulation displacement connecting step, is inserted in a twisted condition into the slots to be insulation-displacement-connected to the terminal, the wire can be press-fitted excessively or inadequately. Also, there is a possibility that the wire fails to be inserted into the slots, and the empty hitting occurs, so that a wire-absent condition develops. Alternatively, there can be encountered abnormal insulation displacement connection in which the wire to be inserted into the adjoining cavity is inserted, together with the proper wire, into one slot, so that the double wire-hitting occurs.
In the conventional insulation displacement connection examination, it is judged that the insulation displacement connection is finished when the insulation displacement connecting blade for press-fitting the wire into the slots, reaches its lower dead point. With this method, however, the above deficiencies can not be detected.
For example, in the case of “wire absence”, the insulation displacement connecting blade reaches the lower dead point without undergoing any resistance, and even in the case of the abnormal insulation displacement connection (double wire-hitting), the insulation displacement connecting condition is not different from the proper insulation displacement connecting condition for one wire if the wires are soft, and if the force for pressing the insulation displacement connecting blade is extremely large.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a method of examining defective insulation displacement connection developing during the insulation displacement connecting operation, and also to provide an apparatus for performing this method.
In the present invention, in order to solve the above problems, by measuring a height of an upper surface of the insulation displacement connected wire from a reference position, the examination of the insulation displacement connection is effected. With this method, the presence of the wire can be directly detected, and therefore information of the insulation displacement connecting height, the wire presence/absence, the abnormal insulation displacement connection and the wire projecting amount, which represent the insulation displacement connected condition, can be obtained.
“The insulation displacement connecting height” is the height of the upper surface of the wire sheath from the reference position at the position of the slot. The reference position in the direction of the height may be any arbitrary position in the space, and can be, for example, an upper surface of a connector-positioning pallet (the bottom surface of the connector).
In the case where the connector (not shown) is of such a design that two terminals
41
are juxtaposed and spaced a distance D
1
from each other in the direction of the length of the wire
50
so that the wire can be insulation-displacement-connected at two portions thereof as shown in
FIG. 5
, the measurement position in the horizontal direction is a middle position A
1
between the two terminals
41
and
41
. In the case where only one terminal
41
is attached to the wire
50
in the direction of the length of the wire, the measurement position in the horizontal direction is a position A
2
at which this terminal
41
exists.
With respect to “the wire presence/absence”, if the wire is present, it is necessarily detected in the measurement of the wire insulation displacement connecting height. If the wire is absent, it detected when the height of the wire sheath from the reference position, measured in this measurement, represents a value smaller than its normal value by an amount equal to the normal outer diameter of the wire.
“The abnormal insulation displacement connection” is encountered, for example, if a plurality of wires are insulation-displacement-connected in a bundled manner into one slot, and in this case, the position of the sheath of the uppermost wire is measured, and therefore the measured value of the above insulation displacement connecting height is extraordinarily large, and therefore it is judged that this is the abnormal insulation displacement connection.
Although “the wire projecting amount” is the amount of projecting of the wire from the side surface of the terminal, this amount itself is not measured, and as shown in
FIG. 5
, a position B, obtained by subtracting an absolute value d of a tolerance from a normal projecting position (that is, a position advanced a normal projecting amount D
2
from the side surface of the terminal
41
in the direction of projecting of the wire
50
), is defined as an examination position, and at this position B, the presence/absence of the wire
50
is detected according to the same procedure as described above for the examination of “the wire presence/absence”, and the judgment is made based on this. More specifically, if the presence of the wire
50
at the examination position B is confirmed, it is decided that the projecting amount is normal, and if it is judged that the wire
50
is absent, it is decided that the projecting amount is not normal.
If not less than two of the wire insulation displacement connecting height, the wire projecting amount, the wire presence/absence and the abnormal wire insulation displacement connection are measured, the defective insulation displacement connection can be detected multilaterally, and the product of a high quality can be obtained.
In order to effect the above examination, there is used the apparatus provided with the CCD laser displacement gauge movable in the direction of juxtaposition of the wires.
In this apparatus, the CCD laser displacement gauge is scanningly moved in the direction of juxtaposition of the wires so that the measurements in the above items can be made.
The reasons why the laser displacement gauge is used are that it is not desirable to apply a load to the wire at the insulation displacement connecting position and that not a contact-type (which applies a load) but a non-contact-type measurement instrumen
Autonetworks Technologies Ltd.
Bennett G. Bradley
Oliff & Berridg,e PLC
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