Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
VIBRATION RESISTANT ELECTRICAL CONNECTOR
FIELD OF THE INVENTION
The present invention relates to electrical connectors; and more
particularly, it relates to electrical connectors of the type which are
referred to
generally as "quick disconnect" connectors and which are used in commercial
and industrial applications, particularly in the field of industrial
automation
and manufacturing.
BACKGROUND OF THE INVENTION
Typically, quick disconnect connectors for commercial and industrial
applications of the type with which the present invention is concerned,
include
a male connector and a mating female connector. The male connector has
metal connecting elements in the form of pins; and they are received in
corresponding sockets or receptacles embedded in the mating female connector.
Typically, these connectors have two to five poles plus a ground connection.
An important aspect of quick disconnect connectors is that there be some
mechanical coupling to secure the male and female connectors together and
maintain electrical continuity. Typically, in connectors of this type, the
female
connector (or the male) is provided with a mating threaded coupling member
(such as a coupling nut); and the mating connector is provided with a mating
threaded coupling portion so that after the electrical connection is
established,
the coupling members provide a mechanical connection securing the electrical
CA 02459894 2006-10-13
connection. In some applications where the handling of the connectors may be
often and perhaps somewhat rough, as well as in applications where the
connectors are mounted to a machine and undergo periodic or continuous
vibration, there is a tendency for the coupling nut to back off from its
threaded
engagement with the male connector, thus creating the possibility of an
inadvertent or unintentional disconnect.
In addition to the problems mentioned above concerning the possibility
that the male and female connectors may become disconnected as a result of
vibration or handling, there is also a disadvantage with existing quick
disconnect connectors in that it takes an appreciable time to secure a
connection, primarily in manually threading the coupling nut of one connector
onto the other connector. The amount of time for assembling a single
connector combination may not be significant in an absolute sense, but when it
is considered that in a large manufacturing environment there are literally
thousands of such connectors around and that machines and control systems
employing the connectors are continuously being re-positioned, tested and re-
assembled, over the period of months or a year, the amount of time required to
assemble and disassemble threaded coupling nuts has proved to be appreciable.
Co-owned, U.S. Patent No. 6,461,179, issued October 8, 2002,
discloses a vibration resistant, quick disconnect connector having thread
segments of flexible material which permits male and female connectors
to be assembled simply by pushing them together. The female connector
has the flexible thread segments on a flexible wall which deflects to
2
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
permit mating engagement when pushed onto a male connector.
Such flexible-thread connectors work very well when assembled to a
corresponding mating conventional connector having threads of matching pitch.
Typically, such conventional connectors have threads of metal or rigid
plastic; and the inter-engagement of flexible thread segments with full mating
threads of rigid material has been found to be satisfactory because the act of
connecting the two is simplified, and the resistance to vibration-induced
disconnect is acceptable. However, in the case of female to male inter-
engagement with mating connectors both having flexible threads the connection
leaves something to be desired for two reasons. First, there is little or no
tactile
feeling that the connection has been completed; second, because the crests of
flexible threads may be somewhat lower than for rigid threads, the ability to
resist vibration-induced disconnect is less than desired.
SUMMARY OF THE INVENTION
The present invention contemplates that one of the electrical connectors
(the female in the embodiment shown) have a cylindrical wall surrounding and
spaced from an insulating insert in which connecting elements in the form of
sockets are embedded. The cylindrical wall of the female connector is made of
molded plastic, such as polyvinyl chloride (PVC) and has a flexibility such
that
it may be deformed upon insertion of a mating male connector in order to
receive and engage with the mating thread segments of the male connector
without a turning or twisting motion. The interior surface of the cylindrical
3
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
wall of the female connector is provided with first and second diametrically
located, discrete segments of internal threads arranged in opposing relation.
That is, one segment of internal threads may extend for approximately 90
degrees about the interior of the cylindrical wall; and a second segment of
internal threads is arranged in opposing or facing relation and located on the
interior surface of the opposite side of the peripheral wall. Between the two
segments of thread, the wall is free of thread and may be smooth and
cylindrical.
When used in connection with the present invention, the term "thread"
includes not only conventional screw threads, extending helically about a
central axis, but also a series of alternating ridges or crests and troughs
arranged perpendicular to the longitudinal axis of the connector (sometimes
referred to as "parallel" threads). Conventional screw threads may be
preferred
because they are compatible with the screw threads found on the many existing
metal or rigid plastic coupling nuts and male connectors found in
manufacturing plants. However, parallel threads, when provided in discrete
segments as disclosed, will engage and can be assembled by pushing two mating
connectors together because the threads are flexible and they are provided in
discrete segments so they will ride over one another upon assembly. Parallel
threads will provide sufficient interlocking to require separating or pull
forces
in a desirable range to resist unintentional disconnects. Moreover, a "thread"
includes at least two adjacent crest/trough combinations, whether parallel or
helical.
4
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
The male connector preferably has corresponding, matching opposing
segments of external thread on an outer cylindrical surface. The male and
female connector inserts are keyed together so that when the keyway of the
female is aligned with the key of the male connector, the matching thread
segments are also aligned.
The male connector may then be inserted into the female connector by
pushing the male connector directly into the female connector after the
respective key and keyway have been aligned. In assembling the male
connector to the female connector, the wall of the female connector deflects
as
the external thread segments of the male connector are assembled to the mating
thread segments female connector. In other words, the outer wall of the female
connector deforms into an elliptical form so that the interior threads of the
female connector ride over the corresponding thread segments of the male
connector.
Once the two connectors are assembled, the threads inter-engage
(whether parallel or helical types). The connection is highly resistant to
vibration-induced disconnect because the male connector cannot be rotated
relative to the female connector since they are keyed together. Moreover, it
has
been found that a substantial but adjustable pull force (in the range of ten
to
thirty pounds, for example) may be designed into the assembled connectors,
depending upon the hardness of the material used in molding the cylindrical
wall of the female connector on which the thread segments are formed and
other factors.
5
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
It will be appreciated that the assembly time for establishing an
electrical/mechanical connection with the improved connectors is substantially
reduced. Moreover, the female connector of the present invention (with screw
threads) is adaptable to mate with existing male connectors having external
metal or other rigid threads, and the male version of the instant connector
with
flexible screw threads is equally adaptable to assembly with existing interior
metal threads of rigid coupling nuts. The male connector of the present
invention may be pushed directly into the existing coupling nuts of female
connectors, or, if desired, the coupling nuts can be threaded onto the thread
segments of the male connectors constructed according to the present
invention.
In order to improve the coupling of a male and a female connector, each
having flexible threads, the present invention provides an annular groove at
the
forward end of one set of thread segments, typically, but not necessarily,
located on the female connector and located on the interior surface of the
flexible wall. A mating annular rib or rim is provided at the base of the
exterior
thread of the male connector. When the two connectors are aligned and
assembled with a linear, pushing motion, the thread segments ride over one
another, the outer wall of the female connector flexing to receive the male;
and,
as the engagement becomes complete, the annular rim of the male connector
snaps into engagement with the annular groove of the female. This provides
both a sensible, tactile feel of completion of the connection, and a solid
mechanical coupling to resist disconnect of the mating flexible threads.
6
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
Further, the outer surfaces of the overmold bodies, for both male and
female are shaped and textured to facilitate gripping and disconnecting with
the
fingers of both hands.
Other features and advantages of the present invention will be
apparently to persons skilled in the art from the following detailed
description
of a preferred embodiment accompanied by the attached drawing wherein
identical reference numerals will refer to like parts in the various views.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side view of a male connector and female connector
constructed according to the present invention in assembled relation;
FIG. 2 is a bottom view of the male connector of FIG. 1;
FIG. 3 is a bottom view of the female connector FIG. 1;
FIG. 4 is a cross sectional view of the assembled male and female
connectors of FIG. 1 shown in partial form and taken through the section line
4-4 as seen in FIG. 1;
FIG. 5 is an end view of the complete male and female connectors seen
in FIG. 1 taken from the right side thereof;
FIG. 6 is a cross sectional view of the complete male and female
connectors of FIG. 1 taken along the section line 6-6 of FIG. 5 with the
threads
partially engaged;
FIG. 7 is a close-up view similar to FIG. 6 without the cables and with
the threads fully engaged;
7
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
FIG. 7A is an enlarged view of the portion of FIG. 7 within the circle 7A
thereof;
FIG. 8 is an end view of the female connector of FIG. 1 looking at the
connecting end thereof;
FIG. 9 is a side view of the female connector of FIG. 1 with a partial
section of the connecting end thereof, taken along the section line 9-9 of
FIG.
8;
FIG. 10 is a view similar to FIG. 8 of the female connector showing
deflection of the flexible wall connection;
FIG. 11 is a cross section view of the female connector taken along the
section line 11-11 of FIG. 10;
FIG. 12 is a side view of the female connector of FIG. 1;
FIG. 13 is a cross section view taken along the section line 13-13 of
FIG. 12;
FIG. 14 is an enlarged side view of the male connector of FIG. 2;
FIG. 15 is a cross section view taken along the section line 15-15 of
FIG. 14;
FIG. 16 is an enlarged end view of the connecting end of the male
connector of FIG. 2; and
FIG. 17 is a cross section view taken along the section line 17-17 of
FIG. 16.
8
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1-3, reference numeral 10 generally designates a male
electrical connector, and reference numeral 11 generally designates a female
electrical connector. The connectors 10, 11 are shown in assembled relation in
FIG. 1, the male connector is shown in bottom view in FIG. 2, and the female
connector is similarly shown in FIG. 3. As used herein, the terms "forward" or
"distal" with reference to a connector, whether male or female, refers to the
connecting end - that is, the end which couples to the mating connector. The
terms "proximal" or "rear" refer to the portion of a connector closer to its
associated cable. "Top" and "bottom" are used for reference only, and do not
designate any particular use side.
Turning first to the female connector 11, it is shown in greater detail in
FIGS. 8 through 13. However, as seen in FIGS. 1 and 3, the exterior of the
female connector includes an overmold body (or simply "overmold") designated
12 which encompasses the connecting elements, to be described. The
connecting elements may be conventional, and they are conventionally
connected to the individual wires of a jacketed cable 13. The overmold body
12, as is known, provides a protective coating over the juncture between the
cable 13 and the individual connector elements of the connector 11, as will be
described. Moreover, the overmold 12 provides a protective sheath and strain
relief for the connector. Similarly, the male connector includes an overmold
body 14 and it may be connected to the individual wires of a cable 15. The
overmold bodies 12, 14 are made of molded plastic such as polyvinyl chloride.
9
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
Turning then to the female connector 11 as seen in FIGS. 8-13, it
includes an insert body 18 of rigid plastic material and having insulating
properties to receive and support individual female connecting elements 19
which are conventional sleeves or receptacles, and a separate, central sleeve
20
for a ground connection. Referring particularly to FIG. 11, the female insert
18
includes a base 22 on which the overmold 12 is formed. To provide greater
mechanical bonding with the overmold 12, the base 22 of the insert may be
provided with peripheral grooves such as those designated 24 in FIG. 11.
Extending forwardly (to the left in FIG. 11) the insert 18 includes a
generally
cylindrical projecting portion 25 integral with the base 22, and forming a
rigid
body for holding and supporting the electrical connecting elements 19, 20.
As best seen in FIGS. 8 and 11, a keyway or slot 27 is formed in the
cylindrical projecting portion 25 which has a diameter less than that of the
base
22 in the embodiment shown. Moreover, at the forward portion of the
overmold 12, there is formed a cylindrical wall 28 which surrounds the
projecting portion 25 of the insert 18. An interior cylindrical surface 29 of
the
cylindrical wall 28 of the overmold is spaced from the cylindrical side of the
projecting portion 25 of the insert 18 to form an annular space generally
designated 30 which, as will be described, receives a surrounding wall of the
male connector.
Turning now particularly to FIGS. 8-10, the interior cylindrical surface
29 has integrally molded onto it, first and second segments of inner 'threads.
These two segments are designated respectively 33 and 34. The threads may
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
be formed in the pattern of a continuous helical thread (screw thread). That
is,
the crests and troughs of the threads on a segment 33 form the same pitch as,
and lead into the threads on the segment 34. The threads are interrupted
however. Moreover, the threads may be a standard thread of screw type found
in conventional connectors of this type having coupling nuts with interior
threads, in which case, of course, the threads are rigid and continuous, such
as
a conventional 12 m x 1 thread.
Alternately, the threads may be parallel -- that is, arranged in planes
perpendicular to the axis of the connector, designated 35 in FIG. 4. The
thread
segments 33, 34 are molded as an integral part of the overmold 12, and
therefore made of the same material and flexible. The molding material may be
a polyvinyl chloride, and have a durometer rating in the range of
approximately
70-100 on the Shore A scale. For the standard thread size indicated above, a
durometer rating of 80 on the Shore A scale provides a 15 pound pull force
required to disconnect the female connector from the male connector to be
described. A durometer rating of 92 on the Shore A scale for the structure
described results in a pull force of approximately 25 pounds to disconnect the
male and female connectors.
Persons skilled in the art will appreciate that pull forces may be designed
over a wide range by adjusting the number of threads, the included angle over
which the thread segments extend and the hardness of the molding material of
the overmold body. Depending on the dimensions and intended application,
hardness ratings ranging from 30 to 40 on Shore A to 75 on the Shore D scale
17.
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
will work, but with correspondingly less or greater pull force required to
disconnect.
Turning particularly to FIG. 9, the thread segments 33, 34 formed on
the interior surface 29 of the peripheral wall 28 are seen to be similar to a
corresponding thread formed in a rigid coupling nut of the type presently
commercially available, however, the segments are not continuous around the
interior of the peripheral wall 28, and the threads are molded of a flexible
plastic material integral with the inner surface 29 of wall 28. An annular
groove 32 is formed peripherally around the cylindrical inner surface 29 of
the
outer flexible wall 28 of the overmold as seen in FIGS. 7A, 11 and 13. Groove
32 need not extend completely around the wall 29, as persons skilled in the
art
will recognize because the two connectors do not twist relative to each other;
that is, the groove could extend in segments or sectors like the threads,
provided the mating rib or rib sectors on the mating connector to be described
below, engage the corresponding groove or groove sectors.
The leading edge of the wall 28 may be chamfered as seen at 37 in FIG.
9 to provide a guide or centering surface when connecting male and female
connectors, and to engage with a correspondingly chamfered surface 50 on the
male connector (FIGS. 14 and 15). The interface may thus provide a seal
against dust, debris and water, though the seal is not intended to be a
pressure
seal. FIG. 13 is a longitudinal cross section of the female connector similar
to
that seen in FIG. 11, but wherein the connector is rotated 90 degrees on its
axis (compare the section lines of FIG. 10 and FIG. 12).
12
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
As best seen in FIG. 1, the overmold material 14 of the female connector
11 is formed to include an indicator 36 which, in the illustrated embodiment,
is in the form of an arrowhead. The indicator 36 may be aligned with a similar
form on the male. As best seen in FIGS. 1, 9 and 13, the outer surface of the
overmold 12 of the female connector 11 is a surface of revolution contoured as
generally designated at 54, including an inner end portion 55 of larger
circumference reducing in diameter proceeding toward the front of the
connectors. The surface is stepped or ridged to provide a shaped, recessed
grip
portion 56 to enhance gripping with the fingers and thumb of one hand. The
outer surface of the overmold 14 of the male connector is similarly shaped,
but
in mirror image, as seen in FIGS. 1, 14 and 15 female connectors during
assembly, as will be apparent from further description. A corresponding
indicator in the form of an arrow is located on the male connector 10 and
designated 38.
Turning now to FIGS. 14-17 a male insert 40, preferably formed of a
rigid, insulating, suitable plastic is generally cylindrical in form and
elongated
axially as seen in FIG. 15. Male insert 40 includes, at its forward portion, a
cavity which is generally cylindrical and designated 42 for housing a
plurality
of male contact or connecting elements in the form of pins 43, and a central
ground pin 44. The protective overmold 14 is formed about the exterior
cylindrical surface 45 of the male insert 40, and the male insert 40 also may
include grooves 45 to improve the mechanical bond with the overmold 14. The
forward end of the male insert 40 is formed into an outwardly extending
13
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
peripheral flange 41. At the forward end of the overmold 14, there are
provided first and second segments of male threads designated respectively 46
and 47 in FIG. 15.
The thread segment 46 is seen in FIG. 14, and it is formed on the outer
cylindrical surface 49 of the forward most portion of the overmold 14.
Forward of the indicator 38, and inboard of the cylindrical surface 49, there
is
the chamfered or frusto-conical surface 50 for engaging and sealing with the
corresponding mating surface 37 of the female connector as described.
The male thread segments 46, 47 may also be formed as segments of a
continuous male screw thread having the same pitch, thread size and diameter
as the corresponding inner threads on the female connector, and as the
corresponding threads on the rigid metal connectors of conventional female
connectors, or they may be parallel threads in the form of ridges/grooves. The
included angle of the thread segments or sectors of the male connector may
also
be 90 degrees, as with the corresponding female thread segments. However,
the thread segments may extend in the range of 60 -120 approximately with
changes in the pull force required for disconnection.
The male insert 40 also includes a key 51 which extends axially of the
connector and is sized to be received in the keyway 27 of the female insert
(see
FIGS. 8 and 16).
Referring now to FIG. 4, when the male connector 10 is assembled to
the female connector 11, as seen in FIG. 4, the key 51 of the male insert 40
is
received in the corresponding keyway 27 of the female insert 18. This not only
14
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
orients and locates the corresponding connecting elements correctly, but it
prevents twisting or turning of the connectors once they are connected
together.
The male connecting elements or pins are received in the corresponding female
connecting elements or sockets; and the frusto-conical surfaces 37, 50 are in
contacting relation.
As seen in FIGS. 7, 7A, 14 and 15, a peripheral rim 53 is formed in the
overmold 14 of the male connector at the base or rear end of the exterior
thread segments 46, 47, but raised above the threads to be seated in the
annular groove 32 of the mating connector (FIG.. 7A).
FIG. 6 shows male and female connectors in partial engaging relation.
Because both the male thread segments and the mating female thread segments
are provided in segments rather than continuous thread, and because the
cylindrical wall 28 on which the female thread segments are formed is
flexible,
when the two connectors are aligned and pushed together, the flexible
cylindrical wall 28 of the female connector becomes somewhat elliptical. That
is, it bulges out laterally as seen by the dashed line in FIG. 10, because the
corresponding male threads 46, 47 push on the female thread segments 33,
34, and force them outwardly; and the opposing unthreaded portions of the
wall 28 come closer together, as also illustrated by dashed line in FIG. 10.
The
process of assembling a male connector to a female connector gives the user a
tactile, feeling indicating correct assembly as the crests of one thread
segment
ride over the crests and into the troughs of the mating thread segment on the
mating female connector. Moreover, when a male and female connector, each
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
having flexible thread segments or sectors are connected together, the annular
rib 53 (or raised segments) is received in the annular groove 32 (or recessed
segments) of the female overmold to effect a tongue-in-groove connection, thus
providing a snap feeling of connection completed and improved interlock
between the male and female connectors. The flexibility of the wall 28 of the
female connector permits the groove to expand to receive the rib. Thus, the
mechanical coupling and sealing may be improved by having the width of the
groove at its opening, wider than the corresponding cross sectional dimension
of the rib.
Once the thread segments are assembled, it is assured that corresponding
mating thread segments are fully engaged because of the locating function
performed by the key and keyway and the chamfered engaging surfaces
mentioned above. The disconnect or pull force, that is, the force necessary to
disconnect the male and female connectors, if both connectors are made as
indicated herein, depends upon the factors described above. However, in any
case, the connector of the present invention is much more resistant to
unintentional disconnection through vibration or handling than are the
previous
connectors made of rigid, full threads and employing a coupling nut.
16
CA 02459894 2004-03-04
WO 03/021720 PCT/US02/27317
Moreover, the pull force needed to disconnect the instant connectors
may be varied according to the application or the intention of the
manufacturer.
Further, the male connector 10 (with flexible screw thread segments) may be
used in combination with existing female connectors having rigid coupling
nuts,
and the female connector 11 may equally well be used with existing commercial
connectors having rigid outer threads such as those almost universally used on
sensor bodies widely found in current industrial automation applications.
Whereas in the illustrated embodiment, the flexible wall and the interior
thread segments are on the female connector, and the exterior thread segment
are on the male connector, they could be reversed with like results.
Having thus disclosed in detail various embodiments of the invention,
persons skilled in the art will be able to modify certain of the structure
which
has been disclosed and to substitute equivalent materials or elements for
those
described while continuing to practice the principle of the invention; and it
is,
therefore, all such modifications and substitutions be covered as they are
embraced within the spirit and scope of the independent claims.
17
