Note: Descriptions are shown in the official language in which they were submitted.
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CROSS-REFERENCE TO RELATED PATENTS
The present invention is related to an improvement
upon United States patent 3,725,844 issued April 3, 1973
to McKeo~n et al. for "Hermaphroditic Electrical Contact",
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assigned to the assignee of the present invention. This
patent is hereafter referred to as the "Brush Contact Patent".
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TECHNICAL FIELD
The present invention relates to an improved
apparatus for inter-connecting two electrical conductors
in electrical circuit relationship, using electrical
contacts as terminals for mating. More particularly, the
present invention is a modification or a hybrid electri-
cal connector assembly wherein one contact is of the
brush-contact type described in the Brush Contact Patent
and the other contact is a conventional contact, for
instance a pin-type contact, preferably having a modified
tapering end portion.
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BACKGI~OUND ART
In the prior art, there are numerous examples of
electrical connectors of the type wherein a pin-type
electrical contact is mated with a socket-type contact.
U.S. Patents 3,221,292 and 4,072,3g4 show two examples o~
such pin and socket contacts for use in electrical con-
nectors as mating terminals. Such pin-type and socket-
type contacts are relatively simple to manufacture and
are made at relatively low manufacturing costs. Such
contacts may be mounted through a grommet to provide
moisture protection.
It is also know in the art to use two electrical
contacts as terminations for electrical conductors, in
which each contact includes a plurality or bundle of
axially-aligned wires with each wire having angled
forward end surface. The mating bundles of axially-
aligned wires have been found to be good electrical
conductors which provide a low mating force contact in an
electrical connector assembly. Electrical contacts of
this type are shown in the referenced Brush Contact
Patent.
The brush contacts shown in the referenced Brush
Contact Patent have the advantage that it has a low
mating force and provides a good electrical connection.
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A brush contact of the type described in the
referenced Brush contact Patent has a plurality of
axially-aligned wires which extend beyond the end of the
sleeve that retains it. Such extension of the aligned
wires is normally not a problem, but in some electrical
connectors applications, moisture protection is desired.
Such moisture protection is frequently achieved by a
rear-mounted grommet. It is also desirable in many
instances that the electrical contact be rear-insertable
and, therefor, must pass through a grommet, they are
susceptiable to damage. Further, the exposed, pointed
forward ends of the brush wires may damage rubber webs
associated with each of the grommet passages, destroying
the moisture protection of the grommet.
Damage to the axially-aligned wires of the brush
contact renders the contact less effective in mating and
carrying electrical current.
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The present inventlon provides an electrical
connector assembly which i9 re]a~ively inexpensive with a
low mating force and good e]ectrical connection between a
conventional contact (e.g., a pin-type or modified pin-type)
and a brush-type electrical contact.
According to the present invention there is provided
an electrical connector assembly of the type including two
mateable electrical connectors, each having a plurality of
electrical contacts mounted therein and positioned to mate
with contacts in the other connector, in the present
invention each contact of the first connector has a plurality
of axially-aligned wires with acutely-angled forward end
surfaces. ~ach contact of the second connector is an
elongated member having a pin-type forward mating portion
so that when the first and second electrical connectors are
mated, each of the forward mating portions of the contacts
in the second connector extend into the plurality of
axially-aligned wires of a respective contact of the first
connector.
Advantageously, the diameter of the pin-type contact
has a predetermined relationship with the diameter of the
bundle of brushwires and the wires themselves.
The foregoing and other objects of the present
invention will be apparent to those skilled in the art in
view of the following description and claims and the
accompanying drawingæ.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a cross-sectional view of an electrical
connector assembly of the present invention.
FIGURE 2 shows the electrical connector assembly of
FIGURE 1, also a cutaway view, with the contacts mated,
bringing the electrical conductors associated with each
contact into electrical circuit relationship.
FIGURE 3 is a cross~sectional view of the brush-type
contact used as one of the mating contacts taken along
the line 3-3 in FIGURE 1.
FIGURE 4 shows a modified pin-type contact having a
tapering end which is preferable in the present
invention. -
FIGURE 5 shows a pin-type contact having a spherical
end of the type used in the prior art.
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DETAILED DESCRIPTION OF TME DRAWINGS
FIGURE 1 is a cross-sectional view of an electrical
connector assembly 10 having electrical contacts 22, 32,
mounted in each passage 23, 33, of two electrical
connector housings 21, 31.
The electrical connector housing may include (as
shown) a shell 21a, an insert 21b including a contact
retention system 21c, 21d and a grommet 21e.
The insert 21b may be of the type shown in a U.S.
patent 3,165,369 to Maston for a multi-piece insert
including contact retention portions 21c, 21d, of maybe a
single piece of molded di-electric material having
integral stops 21c and contact retention figers 21d.
The grommet 21e is preferably made of rubber and
provides a moisture seal to protect the connection from
unwanted moisture which would degrade the electrical
connection between the contacts. The moisture seal is
obtained by several rubber webs 21f, which are resilient
and extend from the grommet 21e.
The grommet 21e and the insert 21b are mounted
within the shell 21a in a known manner. As shown in
FIGURE 1, the shell 21a may include a rearwardly facing
shoulder 21g, with a forwardly facing portion 21g of the
insert engaging the shoulder and the forward face 21h of
the grommet adjacent to the rear face 21g of the insert.
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An electrical contact 22 is mounted within each
passage 23 through the grommet and insert. The contact
22 has an enlarged shoulder which is engaged by the
contact retention system 21c, 21d of the insert and is
releasable securred within the retention system.
The electrical contact 22 is preferably of the
brush-type contact including a plurality of
axially-aligned wires 22a each having a acutely-angled
forward end surface 22b and being retained rearwardly
within a contact sleeve 22c by a crimped portion (not
shown).
The pin-type contact 32 is preferably made of a
conducting material having a forward end surface 32a
which is tapering. The preferred material for the
pin-type contact is brass with gold plating.
FIGURE 2 shows a cross-sectional view of the
electrical assembly of FIGURE 1 with the pin-type and
brush-type contacts mated to bring the associated
conductors into electrical circuit relationship.
As shown in FIGURE 3, the axially-aligned wires 22a
are arranged in a bundle, which, in the one embodiment
shown, includes seven wires. The wires are of a uniform
diameter in there embodiment, each of which being 0.008
inches in diameter. Other sizes of wires and number of
wires in a bundle might be used to advantage in other
applications and, in some applications, the central wire
in the bundle might be chosen to have a diameter than
that of the surrounding wires.
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The brush wires are preferrably each made of
beryllium copper, with an external gold plating. The
brush wires are straight, to form tight, axially-aligned
bundles.
The bundle of wires is held within the contact
sleeve 22c having an inner diameter of approximately .040
inches, compared with the outer diameter of the bundle of
wires which is approximately .025 inches.
The end surfaces 22b of the axially-aligned wires
are preferably cut to have a tapering end portion
inclined at approximately a 30 angle from the axis of
the wire. In other application, greater or lesser angle
may be desirable.
FIGURE 4 shows the preferred embodiment for a
pin-type electrical contact 32 of the present invention
wherein the forward end surface is tapered to an included
angle (shown as ~ in the present view.) While this view
shows that the forward end surface tapered to a point, a
small blunt or radial portion at the forward end of the
pin-type contact could be used to its advantage in place
of the point. Also, the double tapering to a point shown
in FIGURE 4, is not necessarily required and a single
tapering end which extends across, or substantially
across the pin forward edge would suffice. The included
angle ~ is preferably 60~ or less.
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FIGURE 5 shows a pin-type electrical contact 40 or
prior art including a spherical end portion 41. While
such pins might be used to mate with electrical contacts
of the brush, as advantageous and requires the use of a
smaller pin for a given size brush contact to avoid
injury to the brush. The smaller pin required with a
spherical end portion limits the current-carrying
capacity of the assembly and is disadvantageous for that
reason in the present invention.
While sizes have been disclosed in the preferred
embodiment for a seven-wire bundle, there are numerous
changes in the number of the brush wires that are
possible and the sizes of pins that can be used to
advantage in the present invention. Cther examples of
acceptable structure for the present invention include
the following:
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TABLE I
CURRENT PIN SLEEVE NO. OF
CAPACITY DIAMETER DIAMETE~ BRUSH
EXAMPLE(AMP)(INCHE5? ¦INCHES~ WIRES
A 3.0 .02S ~044 7
B 7~5 .~3 .062 19
C 13.0 .063 .092 37
BUNDLE RATIO OF RATIO OF
DIAMETER BUNDLE DIAMETER SLEEVE DIAMETER
EXAMPLE (INCHES TO PIN DIAMETER TO PIN DIAMETER
A .n25 1.00 .1.76
~ .041 .95 1.44
C .058 .92 1.46
Bund].e dia~eter i5 before l~ating
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Of co~rse, a smaller pin contact could be used with
a brush contact of a given size. However, the current
rating of the combination would be lower than that of the
brush contact and thus there would be unnecessary expense
of the larger brush contacts. Conversely, a sma]ler size
brush contact could be used with a given size pin
contact. However, the expense of a larger-than-necessary
pin would be for naught, as the current-carrying capacity
of the assembly would be limited by the brush contact.
Other objects and advantages of the present
invention will be apparent in those skilled in the art of
making electrical connectors in view of the foregoing
description. The size of the brush wires, which has been
considered as a constant of .008 inches, might be
modified to advantage. The material disclosed for the
brush wires and the material for the pin can easily be
changed without departing from the sprite of the present
invention. The foregoing description, accordingly,
should be considered illustrative only and should not be
interpreted to limit the scope of the present invention
which is defined by the following claims.
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