Note: Descriptions are shown in the official language in which they were submitted.
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AN ELECTRICAL CONNECTOR ASSEMBLY
This invention relates to an electrical connector
and more particularly to an assembly for preventing
unwanted uncoupling of a pair of coupled connectors.
An electrical connector assembly is comprised of a
pair of electrical connectors each having a housing
connectable by a coupling nut rotatable mounted to one of
the housings. Each of the housings includes an insert of
dielectric material provided with multiple openings
within which electrical contacts are retained. The
coupling nut generally includes a thread adapted to
engage a thread on the other housing so that when the
threads are engaged and the coupling nut is rotated, the
housings are drawn together mating the contacts within
the housings. Because coupled connectors used in
aircraft are subjected to severe vibration they are
provided with an anti-decoupling mechanism to retain the
connector housings and respective contacts in mated
relationship despite the vibrational forces. An example
of such a mechanism may be found in US. Patent 4,109,990
entitled "Electrical Connector Assembly waving an Anti-
Decoupling Mechanism" issued August 29, 1978. The
anti-decoupling mechanism disclosed in this patent
includes a plurality of radially outwardly extending
teeth around the outside of one of the housings, a
coupling nut having a flange with a circular aperture and
rotatable mounted to the other housing, a spring having a
coiled portion defining an opening, and a radial project
lion that engages the teeth, and a pin pressure fit into
the circular aperture in the coupling nut flange and in
the opening in the spring to mount the spring to inside
of the coupling nut. The configuration of the portion of
the pin located in the circular aperture in the coupling
nut is square to provide edges that cut into the walls
of the circular hole in the coupling nut to secure the
pin to the coupling nut. The pin may be made by forming
a cylindrically shaped pin on a screw machine and then
forming four flat surfaces and four edges on one end
portion with a milling machine. The pin may also be made
from square stock but such stock is more expensive than
round stock and requires more handling of the stock to
manufacture the pin.
Recently, a problem was recognized with the fore-
going types of connectors when the coupling nut thread
would not tighten completely to the thread on the other
housing or the threads would bind. In some instances,
the electrical connections between adjacent contacts were
shorted out. These problems were traced to pieces of
metal between the threads and between the contacts. The
piece of metal between the threads also caused unneces-
spry wear of the threads. As a result, care was taken to
remove any metal particles or burrs off a thread after a
thread was machined into the coupling nut and housing.
however, the problem persisted until it was recognized
that when the pin, mounting the spring inside the
coupling nut, was pressure fit into the circular aperture
in also creating burrs. Failure to remove these burrs
caused the foregoing problems to continue as well as
adversely affecting the anti-decoupling mechanism by
interfering with the deflection of the spring, as the
burr becomes lodged behind the spring.
Disclosure of the Invention
This invention eliminates the burrs previously
produced by the pin that mounted the anti-decoupling
spring to the coupling nut. The invention is
characterized by a mounting pin that has a helical
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thread in the end portion of the pin that is pressure fit
into the circular aperture in the coupling nut.
Accordingly, an advantage of this invention is to
eliminate metal burrs that would occur when a pin is used
to mount an anti-decoupling spring to a coupling nut.
Another advantage of this invention is that the
mounting pin can be made more economically by a single
manufacturing machine by eliminating the need for a
second machine to mechanically mill flat sides on a
portion of the mounting pin.
Another advantage of this invention is that the
mounting pin can be made from round stock eliminating the
need to use more expensive square stock.
Detailed Description of the Invention
FIGURE 1 is a diagrammatic view of a mounting pin
incorporating the principles of the invention.
FIGURE 2 illustrates a cross-sectional view of a
portion of an electrical connector assembly having an
anti-decoupling mechanism.
FIGURE 3 is an exploded view of a portion of the
coupling nut, a spring member and a pin for mounting the
spring to the coupling nut.
Referring now to the drawings, FIGURE 1 illustrates
a mounting pin 10 incorporating the principles of this
invention. One end portion of the muting pin 10
includes a plurality of helical threads 11 and the other
end portion includes a reduced diameter cylindrical
portion 12 terminating in a tapered end portion 13. The
tapered end portion 13 is designed to facilitate the
entry of the pin 10 into an aperture or passage. The end
portion 14 of the threads 11 is tapered to facilitate the
entry of the threads 11 into a passageway.
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FIGURE 2 illustrates a cross-sectional view of an
electrical connector assembly having an anti-decoupling
mechanism which comprises a spring 20 having a radially
inwardly extending projection 21 and a coiled end portion
22 defining an opening, a housing 30 having a plurality
of radially outwardly extending teeth 31 thereon that
engage the projection 21, a coupling nut 40 having a
radially inwardly extending flange 41 that has a circular
aperture 42 therein and a mounting pin 10 in pressure
tight relationship with the opening in the coiled end
portion 22 of the spring 20 and the circular aperture 42
in the coupling nut 40. Mounted within the housing 30 is
a dielectric inset 32 and one or more electrical
contacts 50 adapted to mate with respective contacts in
another housing (not shown). The angle of the surfaces
on the teeth 31 and on the projection 21 in the spring
are designed to impede rotation of the coupling nut 40 in
the direction that would uncouple the coupling nut 40
from the housing 30.
FIGURE 3 illustrates how the pin 10 mounts the
spring 20 to the coupling nut 40. The spring 20 is a
radially deflectable member that includes a radial
projection 21 and a coiled portion 22 defining an opening
adapted to receive the cylindrical portion 12 of the pin
10 in pressure tight relationship. The coupling nut 40
includes on the inside of one end thereof a plurality of
threads 43 and at the other end a circular aperture 42 in
the radially inwardly extending annular flange 41.
Preferably, the diameter of the threaded portion of the
pin 10 is .079 to .082 inches (.200 to .208 centimeters)
and the diameter of the circular aperture 42 in the
flange 41 is .069 to .073 inches (.175 to .185 genii-
meters) to provide a pressure tight fit of the pin 10 in
the aperture 42.
The inventor believes that when an axial force is
applied to the pin 10, to pressure fit the pin 10 into
the circular aperture 42 of the coupling nut 40, burrs
are eliminated because the threads in the pin displace
material of the walls into the area between the crests of
the threads rather than cutting material loose and
pushing the loose material through aperture 41 as did the
previous pins. Since the threads 11 in the pin 10 rotate
into the material, they do not cause metal burrs which
come loose from the coupling nut and adversely affect the
threading of the coupling nut to the other housing. The
pin 10 incorporating the principles of this invention can
be made on one machine, i.e., a screw machine and
eliminates the need to use a second machine to mill flat
surfaces in the pin 10 to form edges on the portion of
the pin that will be located within the circular aperture
42 of the coupling nut 40. Hence, the cost of
fabricating the mounting pin 10 has been reduced.
