Note: Descriptions are shown in the official language in which they were submitted.
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CONTACT RETENTION ASSEMBLY
BACKGROUND OF THE INVENTION
The presen-t invention relates generally to an
electrical connector and, more particularly, to a contact
retention assembly for an electrical connector, and a
method of making the same.
It is well kno~m in the art that it is desirable
to use a one-piece insulator in an electrical connector
member in which the contacts are mounted, both to reduce
manufacturing costs and to avoid voltage breakdowns from
occurring which might otherwise occur at the interface
between front and rear insulators of a two-piece insulator
assembly.
In one prior art arrangement usin~ a one-piece
insulator, the contact passage is provided with shoulders
at each end formed by the use of an aluminum bushing
located on a mold core pin during the insulator molding
operation. The bushing is removed by etching in an acid
bath. A contact retention clip is then snapped in place
between the shoulders. The clip may be similar to that
disclosed in U. S. patent No. 3,158,424 to Bowen. However,
this assembly is expensive to manufacture because of the
etching step.
U. S. patent No. 3,494,998 to Anhalt teaches a method
of mounting a contact retention clip in a one-piece insulator
in which a clip is slidably mounted into a passage in the
insulator to abut a shoulder therein. An appropriate amount
of heat and pressure is then applied to the rear of the
insulator adjacent to the ~assage opening to deform the
insulator material surrounding the opening so that a
shoulder or abutment is formed in the insulator engaging
the rear edge of the clip. If necessary r a sui-table mandrel
is slidably insexted within the passacJe to support the
insulator material and the clip during the deforming opera-
tion. This technique has the disadvantage that it is
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difficult to control the deformation of the rear of the
insulator containing a large number of contact passayes.
As a conse~uence, the rear surface of the insulator may
be uneven resulting in unequal push-out forces on -the
clips in the insulator.
U. S. patents Nos. 4,114,976 and 4,187,650, both to
Selvin et al., disclose a contact retention assembly in
which a clip having outwardly extending barbs thereon is
inserted into a contact passage in a one-piece insulator.
Thereafter, a heated probe is pushed into the rear of the
clip to cause it to expand outwardly. Because the probe
is heated, the material of the insulator adjacent to the
barbs softens so that the barbs will become embedded into
the wall of the passage during the expansion of the clip.
U. S. patent No. 3,571,784 to Naus discloses an
additional form of contact retention assembly having a
one-piece insulator. The contact retention clip is a
two-piece assembly comprising an inner tubular member and
an outer sleeve surrounding the inner member~ The contact
retention fingers are struck from the wall of the inner
member. A lip at the forward end of the inner member is
bent back onto the outer surface of the member to provide
a rearwardly facing shoulder. The outer sleeve abuts the
shoulder, and covers the apertures formed in the inner
tubular member from the striking of the retention fingers
therefrom. The thus described retention clip assembly is
mounted on a core pin, and the one-piece insulator is
molded therearound. The outer sleeve prevents molding
material from entering the apertures behind the retention
fingers which would restrict outward movement of the finyers
when a contact is mounted in the clip. Such method has the
disadvantage that i-t is relatively expensive. The loadiny
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of the retention clips on core pins is time consuming, and
substantially reduces the time in which insulators may be
molded in sequence. Thus, preferably it is desirable to
; mold the insulator first and then insert the clips there-
into, which may be accomplished quite rapidly by automated
techniques.
It is the object of the present invention to
provide an improved contact retention assembly and method
of making the same which overcomes the above-described and
other disadvantages of the prior art contact retention
assemblies and methods.
SUMMARY OF THE INVENTION
According to one aspect of the present invention
there is provided a contact retention assembly comprising
an insulator having a passage therethrough extending from
a front face to a rear face thereof. A rearwardly facing
shoulder is formed in the passage. A contact retention
clip is mounted in the passage behind the shoulder. The
clip comprise~ an inner tubular member ~urrounded by an
outer sleeve. The inner member embodies at least one for-
wardly and inwardly extending resilient retention finger.
The rear end of the sleeve is flared outwardly and is
embedded in the wall of the passage.
According to another aspect of the invention,
there is provided a method of making a contact retention
assembly comprising the steps o~ providing an insulator
having a passage therethrougll, providing a contact
retention clip comprising an inner tubular member
surrounded by an outer ~leeve, the inner member embodying
at least one forwardly and inwardly extending retention
finger, inserting the clip into the passage, and flaring
outwardly the rear end of the sleeve to embed the Rame
into the wall of the passage.
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Preferably the flaring operation is performed
without heating the insulator, thus avoiding degradation
of the insulator material and, consequently, minimizing
the possibility of voltage breakdowns occurring between
the adjacent contact passages. Also, the method of the
invention is less expensive and time consuming than mold-
ing an insulator around contact retention clips mounted on
core pins such as disclosed in the Naus patent.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a fragmentary longitudinal sectional
view through the contact retention assembly of the present
invention;
Fig. 2 is a sectional view similar to Fig. 1 but
showing the contact retention clip prior to the flaring
operation, and a tool positioned outside the insulator
utilized for the flaring operation; and
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Fig. 3 is a sectional view similar to Fig. 2
showing the tool pushed into the clip to flare the
outer end portion thereof into the wall of the contact
passage.
DESCRIPTION OF THE PREFERRE~ EMBODIME~T
Referring now to the drawings in detail, there is
illustrated in Fig. 1 the contac-t retention assembly of
the present invention, generally designated 10. The
assembly comprises an insulator 12 having a contact
passage 14 therein extending from a rear face 16 to the
front face 18 of the insulator. The passa~e includes a
relatively large diameter rear section 20 opening at the
rear face of the insulator, and a forward smaller diameter
section 22 joined to the rear section by a rearwardly
facing annular shoulder 24. The forward section 22 of
the contact passage opens to the front face 1~ of the
insulator through a restricted bore 25 having a tapered
entry 2~ leading thereto.
A contact retention clip, generally designated 28~
is mounted in the rear section 20 of the contact passage,
with the front end of the clip abutting the shoulder 24
in the passage. The clip may be essentially the same
as the clip disclosed in the aforementioned Naus patent.
That is, the clip comprises an inner tubular member 30
surrounded by an outer cylindrical sleeve 32 which has
a relatively tight fit around the inner member. The
inner member has a lip 33 at its forward end which is
reversely bent back onto the outer surface o the cylin-
drical body of the inner member. A longitudinal slot 34
extends the entire length of the inner tubular member.
A pair of resilient retention fingers or tines 36 are
struck rom the wall of the inner member 30 and extend
forwardly and inwardly. The ends of the retention fingers
are adapted to engage a rearly facing shoulder on a
contact, not shown, mounted in the passage 14 ~or re-
stricting rearward movement of the contact therein. The
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front of the outer sleeve 32 abuts the edge 38 of the
` lip 3,. The rear portion 40 of the outer sleeve is
flared outwardly and is embedded in the wall of the
rear section 20 of passage 14 to prevent rearward move-
S ment of the clip in the passage. Thus, it will be seen
that the portion of the passage 14 behind the clip 28
has a diameter greater than that of the inner tubular
member 30 at its rear end in contrast to the contact
retention assembly in the aforementioned Naus patent in
which the insulator which is molded around the clip forms
a shoulder engaging the rear ends of both the inner tubular
member and outer sleeve of the clip.
Figs. 2 and 3 depict the method for making the
contact retention assembly 10 illustrated in Fig. 1. As
seen in Fig. 2, when the clip 28 is initially inserted
into the passage 14, the outer sleeve 32 of the clip has
a cylindrical configuration throughout its entire length,
as does the aforementioned Naus clip. Also, similar to
the Naus clip, the outer sleeve 32 is formed of a relatively
soft metal such as beryllium copper alloy which has not
been heat treated. The inner tubular member is normally
stamped from a flat piece of sheet metal and formed into
a cylinder. Then it is heat treated to retain its con-
figuration. The inner tubular member may therefore be
formed o a beryllium copper which is readily heat treated.
The insulator must be formed of a material which is capable
of being deformed when sufficient force is applied thereto
by a relatively pointed edge, such as is provided by the
flared rear end 40 of the outer sleeve. Thus, preferably
the insulator 12 is formed of a thermoplastic material
such as a polysulfone type polymer.
Fig. 2 also illustrates a probe 42 which may be
utilized for flaring the rear portion of the outer sleeve
32 of the contact retention cli~. The probe comprises a
cylindrical body 44 having a tapered forward end 46. The
tapered end of the probe is joined to the cylindrical
section of the body 44 by a dished annular shoulder 48.
The diameter of the cylindrical body 44 is essentially
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the same as the inner diameter of the sleeve 32, while
the cross section of the tapered forward end 46 of the
probe is slightly less than the internal diameter of the
inner tubular member 30 so that the probe may be slid
into the clip.
Fig. 3 illustrates the probe 42 pushed into the
rear of the clip 28 with the dished shoulder 48 of the
probe bearing against the end of the inner member 30
causing both it and the rear portion of the outer sleeve
32 to flare outwardly. Since the outer sleeve is formed
of a relatively so~t material, the rear portion 40 of the
sleeve will retain its flared configuration as shown in
Fig. 1 when the probe is removed therefrom, but the rear
portion of the inner tubular member 30 will return to its
normal cylindrical configuration due to the fact that the
inner member has been heat treated. The longitudinal
slot 34 in the inner member facilitates its outward ex-
paIlsion when the proba 42 is inserted therein.
The invention is not limlted to the specific
configuration of the clip 28 as illustrated in the drawing.
For example, the shoulder 38 provided by the edge of the
lip 33 could be formed by an outwardly extending flancJe
on the front of tubular member 30/ rather than by bending
a lip back onto the outer surface of the inner member.
In addition, the rear-ends o~ the inner member 30 and
outer sleeve 32, when the clip is initially inserted into
the passage 14, need not be flush as shown. That is, the
rear end of the outer sleeve may e~tend outwardly beyond
the rear of the inner tubular member, if desired, but in
such case a larger cross-section probe 42 would be required
to flare the rear end of the outer sleeve outwardly into
the wall of the contact passage.
Because the insulator 12 is not molded around
contact retention clips mounted on core pins, as in the
3s aforementioned Naus method, the insulator may be pre-
- molded in larcJe numbers very rapidly. The clips 2~ of
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the invention may be rapidly and easily inserted into
the contact passages in the insulator by automated
machinery, and a gang of probes 42 may be inserted
simultaneously into the clips to set them in the passages
utilizing the novel method of the present invention.
