U.S. patent number 3,880,487 [Application Number 05/381,267] was granted by the patent office on 1975-04-29 for low cost sealed connector.
This patent grant is currently assigned to International Telephone and Telegraph Corporation. Invention is credited to David S. Goodman, Jack Langenbach, Willys T. Lemm, Wilfred L. Mintz, Gerald J. Selvin.
United States Patent |
3,880,487 |
Goodman , et al. |
April 29, 1975 |
Low cost sealed connector
Abstract
A low cost sealed electrical connector in which the mating plug
and receptacle connector members are each formed of a unitary body
of elastic pliant molded material in which mating contacts are
mounted in aligned contact passages. The receptacle connector
member is formed with a resiliently radially expandable sleeve
which slidably receives a forwardly extending annular section of
the plug connector member. Such annular section defines a cavity
which slidably receives a central projection formed on the
receptacle connector member. Either a deformable lip or a plurality
of ribs are formed on the outer surface of the plug annular section
which have an interference fit with the inner surface of the sleeve
thereby providing a primary interfacial seal therebetween. The
projection on the receptacle provides mechanical support for the
plug annular section and also is in sealing engagement therewith so
as to provide a secondary seal. A lip seal or sealing ribs are
formed on the wall of each contact passage to provide a rear seal
for the insulated wire which is connected to the contact mounted in
the passage.
Inventors: |
Goodman; David S. (Orange,
CA), Selvin; Gerald J. (Huntington Beach, CA),
Langenbach; Jack (Newport Beach, CA), Lemm; Willys T.
(Costa Mesa, CA), Mintz; Wilfred L. (Granada Hills, CA) |
Assignee: |
International Telephone and
Telegraph Corporation (New York, NY)
|
Family
ID: |
23504363 |
Appl.
No.: |
05/381,267 |
Filed: |
July 20, 1973 |
Current U.S.
Class: |
439/282;
439/279 |
Current CPC
Class: |
H01R
13/50 (20130101); H01R 13/4223 (20130101); H01R
13/5219 (20130101) |
Current International
Class: |
H01R
13/50 (20060101); H01R 13/422 (20060101); H01R
13/52 (20060101); H01r 013/52 () |
Field of
Search: |
;339/59-61,91,94 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: McGlynn; Joseph H.
Attorney, Agent or Firm: Peterson; Thomas L.
Claims
What is claimed is:
1. An electrical connector comprising:
mating plug and receptacle connector members each comprising a
one-piece unitary elastic pliant body;
said receptacle connector member embodying a resiliently
radially-expandable forwardly-extending sleeve portion and a
central forwardly-extending supporting projection spaced from said
sleeve portion to define a generally annular recess therebetween,
said sleeve portion having a generally cylindrical inner surface
surrounding said projection;
said plug connector member embodying a forwardly-extending annular
section slidably insertable into said annular recess, said
projection providing a relatively rigid support for said annular
section;
said annular section providing a central cavity slidably receiving
said projection and having a generally cylindrical outer
surface;
one of said cylindrical surfaces being smoothly continuous and
substantially free of undulations throughout its length;
a plurality of longitudinally-spaced annular ribs integral with the
other of said cylindrical surfaces, said ribs being adapted to be
compressively deformed in a sealing interference fit with said
smoothly continuous cylindrical surface to form a first seal having
a plurality of sealing contacts over a length of said receptacle
connector member defined by said longitudinally-spaced ribs;
said annular section having an inner surface adapted to mate in
sealing engagement with a cooperating outer surface of said
supporting projection to form a second seal underlying said first
seal;
longitudinally extending aligned contact passages in said plug and
receptacle connector members, said receptacle connector member
contact passage extending through said projection and said plug
connector member contact passage opening into said cavity;
a plurality of annular integral ribs on the wall of each of said
passages adjacent to the rear thereof dimensioned to have an
interference fit with an insulated wire terminating in a contact in
the forward portion of said passage; and
means in each said passage for removably retaining a contact
therein.
2. An electrical connector as set forth in claim 1 wherein:
the outer periphery of each said rib on said other cylindrical
surface has a convexly curved configuration in longitudinal
cross-section.
3. An electrical connector as set forth in claim 1 wherein:
said supporting projection and said annular section have mating
frusto-conical surfaces.
4. An electrical connector as set forth in claim 1 wherein:
each said contact retaining means is integrally formed on the wall
of each said passage.
5. An electrical connector as set forth in claim 1 wherein:
the inner periphery of said ribs on said contact passage walls have
a convexly curved configuration in longitudinal cross-section.
6. An electrical connector as set forth in claim 1 wherein:
the outer surface of said supporting projection and the wall of
said cavity are in sealing contact.
7. An electrical connector as set forth in claim 1 including:
latching means in addition to said ribs integrally formed on said
plug and receptacle connector members for releasably holding said
members in mating engagement.
8. An electrical connector as set forth in claim 7 wherein:
said latching means comprises an inwardly extending flange on said
receptacle connector member adjacent to the end of said sleeve
defining a rearwardly facing surface and a rearwardly facing
surface formed on said plug connector member behind said sealing
means engageable with said surface on said receptacle connector
member, said surfaces being inclined so that upon applying a
disengaging force to said connector members said flange will expand
radially outwardly.
9. An electrical connector as set forth in claim 1 including:
a contact mounted in each of said contact passages, each said
contact being connected to an insulated wire extending through the
rear of its corresponding contact passage; and
said annular ribs on the wall of each said contact passage
sealingly engaging said insulated wire.
10. An electrical connector as set forth in claim 9 wherein:
each said contact is formed with an annular recess; and
each said contact retaining means extends into the annular recess
in its respective contact limiting longitudinal movement of said
contact.
11. An electrical connector as set forth in claim 10 wherein:
each said contact retaining means comprises a radially inwardly
extending annular flange being sufficiently resilient and pliant to
allow said contact to pass therethrough.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to an electrical connector and,
more particularly, to a low cost sealed electrical connector
suitable for use, for example, in automotive vehicles.
DESCRIPTION OF THE PRIOR ART
There are generally two different types of electrical connectors,
namely, sealed and unsealed. The term, sealed, as used herein
refers to the ability of a connector, that is, the mated plug and
receptacle members, to prevent the intrusion of moisture or other
contaminants into the area of the connector containing the
electrical contacts.
There are presently available a number of electrical connectors
which are of the sealed type. However, methods to achieve sealing
in these connectors are expensive and have functional limitations
which render the connectors unacceptable for some applications. In
one form of such a sealed electrical connector, an elastomeric
sealing member is faced on each end of the respective parts of the
connector. The central sealing member is referred to in the art as
an interfacial seal. To function, this seal must be held in a
compressed condition against the mating surfaces of the connector
parts. This requires some form of positive coupling or latching
between such parts which adds to the cost of the connector. Loss of
this pressure between the parts will allow moisture entry into the
connector.
In another form of a sealed connector, the entire body of the
connector is formed of a plastic material. Typically, the central
or interfacial seal for the connector is provided by the sealing
engagement of a forward cylindrical portion of the plug with a
cylindrical recess formed in the forward end of the receptacle
connector member of the connector. In addition the rear seal, that
is, the seal between the contact passage and the contact, is
provided simply by an interference fit between the mating
cylindrical surfaces of the parts. A connector of this particular
form is described in U.S. Pat. No. 3,601,760. Such a connector
however is not capable of entirely preventing the intrusion of
moisture or other contaminants over a wide variety of temperature
and environmental conditions as encountered in automotive vehicles.
It is also known in the art to provide rubber grommets in
connectors in which resilient sealing ribs are formed in the
contact passages extending through the grommets. Other rear sealing
techniques are also known. For example, as disclosed in copending
application of John E. Barr, Ser. No. 298,416, filed Oct. 17, 1972,
entitled "Low Cost Sealed Connector and Method of Making Same",
assigned to the assignee of the present application, a radially
deformable collet is forced into an annular space between an
insulated wire joined to a contact and the wall of the contact
passage in the connector insulator to provide a rear seal. The
interfacial or central seal for this connector is provided
separately for each contact pair in the form of a projection having
ribs thereon which have an interference fit with the walls of a
recess formed in the mating connector member. While all the
aforementioned techniques have been known and utilized, still no
connector has yet been devised which adequately prevents the
intrusion of moisture or other contaminants into the interior
thereof and which is sufficiently low in cost to be practical from
an economic standpoint for use on automotive vehicles. It is the
purpose of the present invention to provide such a connector.
SUMMARY OF THE INVENTION
It is the principal object of the present invention to provide an
improved low cost sealed electrical connector.
According to the principal aspect of the present invention, there
is provided a low cost sealed electrical connector in which the
mating plug and receptacle connector members each comprises a
unitary body of elastic pliant material with electrical contacts
mounted in aligned passages in the bodies. The receptacle connector
member embodies a resiliently radially expandable forwardly
extending sleeve portion which slidably receives an annular section
which extends forwardly from the plug connector member. Annular
sealing means is integrally formed on one of the connector members
extending radially between the sleeve portion of the receptacle
connector member and the annular section of the plug connector
member. A projection is formed on the receptacle connector member
which extends into the cavity defined by the annular section of the
plug connector member. This projection provides a relatively rigid
mechanical support for such annular section thus assuring that an
effective primary interfacial seal is provided between the mated
parts. In addition, the projection on the receptacle connector
member is in sealing engagement with the wall of the cavity in the
plug connector member so that a secondary seal is formed in series
with the primary seal, thereby assuring that contaminants and
moisture external of the connector will not intrude into the
central interior area of the connector containing the electrical
contacts. Rear seals for the insulated wires connected to the
contacts are provided by either a plurality of ribs or a radially
extending lip integrally formed on the wall of each contact
passage. A connector embodying the aforementioned interfacial and
rear seals has been found to be air and moisture tight over a wide
variety of temperature and environmental conditions. In addition,
the connector bodies may be molded as unitary parts thereby
minimizing manufacturing and assembly costs.
Other aspects and advantages of the invention will become more
readily appreciated by reference to the following detailed
description when considered in connection with the accompanying
drawings in which like reference numerals designate like or
corresponding parts throughout the various views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial longitudinal sectional view taken along line
1--1 of FIG. 2 showing mated receptacle and plug members of a
connector embodying the features of the present invention;
FIG. 2 is an end view of the plug connector member illustrated in
FIG. 1;
FIG. 3 is a fragmentary sectional view showing a modified form of
the interfacial seal of the invention;
FIG. 4 is a fragmentary sectional view showing another alternative
form of the interfacial seal of the invention;
FIG. 5 is a fragmentary sectional view showing still a further form
of the interfacial seal of the invention;
FIG. 6 is a fragmentary sectional view showing an alternative form
of a rear seal which may be utilized in the connector of the
invention; and
FIG. 7 is a fragmentary sectional view illustrating a modified form
of a contact retention element in accordance with the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference is now made to the drawings in detail, particularly FIGS.
1 and 2, which illustrate a preferred form of the electrical
connector of the present invention, generally indicated 10. The
connector comprises mated receptacle and plug members 12 and 14,
respectively. Except for the contacts mounted therein, each
connector member consists of a unitary mass of molded elastic
pliant material which is chemically resistant to hostile
environments and varying temperature conditions.
Any thermoplastic elastomer, such as polyurethane polyester, for
example could be utilized as the material of the plug and
receptacle connector members. It will be appreciated, however, that
other elastomers could be utilized if they possess the required
characteristics of resiliency, flexibility and softness to produce
effective seals when configured in accordance with the present
invention, as will be described later herein.
The receptacle connector member 12 is formed with a resiliently
radially expandable forwardly extending cylindrical sleeve 16. A
central forwardly extending projection 18 is also formed on the
receptacle connector member 12 inside the sleeve 16. The outer
surface 20 of the projection 18 is spaced from the inner
cylindrical surface 22 of the sleeve to define therebetween an
annular recess 24.
The plug connector member 14 is formed with a forwardly extending
annular section 26 which provides a central cavity 28. When the
receptacle and plug connector members are mated, as illustrated in
FIG. 1, the projection 18 is slidable received within the cavity 28
and the annular section 26 is slidably received in the annular
recess 24.
An interfacial seal, generally designated 30, is provided between
the cylindrical inner surface 22 of the sleeve 16 and the
cylindrical outer surface 32 of the annular section 26 of the plug
connector member. In the preferred embodiment of the invention, the
interfacial seal comprises a plurality of annular ribs 34
integrally formed on the annular section 26 of the plug connector
member. The ribs extend from the cylindrical outer surface 32 of
the plug radially toward the cylindrical inner surface 22 of the
sleeve 16. The ribs are dimensioned so as to have an interference
fit with the sleeve 16. Compressive deformation of the ribs, in
intimate contact with the smooth cylindrical inner surface of 22 of
the sleeve 16, causes an elastic deformation of the sleeve, as well
as a slight bulging of the outer surface of the sleeve as indicated
at 36. The compressive deformation of the ribs and elastic
deformation of the sleeve 16 results in an air and moisture tight
primary labyrinth seal between the plug and the receptacle
connector members. Since the projection 18 on the receptacle
connector member underlies this seal, it provides a relatively
rigid support for maintaining sealing engagement between the ribs
34 and the sleeve 16. Preferably the outer surface 20 of the
projection 18 has a frusto-conical configuration which mates with
the wall 38 of the cavity 28 in the plug connector member that has
a like frusto-conical configuration. The mating frusto-conical
surfaces 20 and 38 tend to create a wedging action between the
annular section 26 and the projection 18 when the plug connector
member is mated with the receptacle connector member thereby
enhancing the sealing engagement of the ribs 34 with the inner
surface 22 of the sleeve 16. In addition, the engagement of the
mating frusto-conical surfaces 20 and 38 produces a secondary seal
in series with the primary seal provided by the ribs 34 thus
assuring that air, moisture or other contaminants do not enter the
interior of the connector.
Latching means, generally designated 40, is integrally formed on
the two connector members for releasable holding the same together.
Such latching means comprises an integral, radially inwardly
extending flange 42 formed on the sleeve 16 adjacent to its outer
end. The sleeve is beveled at its inner surface to provide a
frusto-conical lead surface 44 which facilitates insertion of the
annular section 26 of the plug connector member into the receptacle
connector member. A radially outwardly extending flange 46 is
formed on the plug connector member. This flange is positioned
behind the flange 42 when the connector members are mated. The
flange 42 provides a rearwardly facing inclined surface 48. A
similarly inclined rearwardly facing surface 50 is formed on the
flange 46 adjacent to the surface 48. Since the sleeve 16 is
resiliently radially expandable, when the plug connector member is
initially mated with the receptacle connector member, the flange 42
will ride over the surface of the ribs 38 and the flange 46 until
it passes the inclined surface 50 whereupon the flange will
contract thereby latching the two connector members together. To
separate the connector members, the members are pulled axially
apart whereupon the flange 42 will expand radially outwardly due to
the engagement of the inclined surface 48 on flange 42 with the
inclined surface 50 on flange 46 whereby the latching means is
uncoupled thus allowing full disengagement of the connector
members. It will be appreciated that due to the resiliency of the
sleeve 16, the ribs 34 may be shifted axially with respect thereto
during the engaging and disengaging of the connector members.
It is noted that the forward portions of the plug and receptacle
connector members are shaped so that the plug connector member
fills nearly all the space within the receptacle connector member,
namely the annular recess 24. Thus, when the two halves of the
connector are mated, air contained within is caused to be expelled.
Displacement of this air within the connector body produces a
condition which results in a slightly greater than atmospheric
pressure within the connector. This pressure resists ingress of
moisture or air into the interior of the connector.
The receptacle connector member 12 and plug connector member 14 are
provided with a plurality of axially aligned longitudinally
extending contact passages 52 and 54, respectively. Three such
passages are shown in FIG. 2 for each connector member by way of
example only. Obviously, a greater or smaller number of passages
could be provided if desired. A socket contact 56 is positioned in
each of the passages 52 while a pin contact 58 is positioned in
each of the passages 54. In FIG. 1, one set of aligned passages 52
and 54 are shown without the contacts mounted therein to clarify
the disclosure. Each contact terminates an insulated wire 60. In
FIG. 1, the contacts are shown as being of the closed barrel type,
the barrel being crimped onto the wire. The contact passages 52 in
the receptacle connector member extend through the projection 18
while the contact passages 54 in the plug connector member open
into the central cavity 28 of the plug connector member. The pin
contacts 58 extend outwardly into the cavity for engagement with
the socket contacts 56 when the connector members are mated. Thus,
the mated contacts are disposed within the interior of the primary
interfacial seal 30 and the secondary seal provided by the mating
frusto-conical surfaces 20 and 38.
Means are integrally formed on the receptacle and plug connector
members for retaining their respective contacts therein. Such means
comprises a flange 64 which extends radially inwardly from the wall
of each contact passage. Said flange is sufficiently resilient and
pliant to allow a contact to pass therethrough when it is inserted
through the rear of the contact passage. Each contact is formed
with an annular recess 66. The depth of the recess 66 and the
radial dimension of each flange 64 are such that the flange will
have a snug fit in the recess to hold the contact against
appreciable longitudinal movement relative to the connector member
body.
A rear seal, generally designated 70, is provided between the rear
portion of each contact passage in the connector members and the
insulated wire 60 mounted therein. In FIG. 1, such rear seal
comprises a plurality of radially inwardly extending deformable
ribs 72 which are integral with the wall of the passage. These ribs
are dimensioned so as to have an interference fit with the
insulation covering on the wire 60 thereby producing an intimate
mechanical contact and labyrinth seal between the insulated wire
and the connector member body. As pressure increases on the one or
either side of this seal, the pressure acts on the wire insulation
and body material causing the wire insulation to plastically deform
and the body elastomer to elastically conform with increasing
pressure. This results in a tight seal between the wire insulation
and connector body. Preferably the outer periphery of the ribs 34
and the inner periphery of the ribs 72 have a convexly curved
configuration in longitudinal cross-section. This configuration of
the sealing ribs has been found to provide a far more effective
sealing engagement than with ribs which have a flat outer or inner
perimeter as the case may be.
Preferably the rear sections 74 of the receptacle and plug
connector members are molded so as to have a reduced cross-section
as best seen in FIG. 2. The contact passages extend through the
rear sections 74 of the connector body. Each such secton is formed
with three sides 76 disposed closely as possible to the walls of
the passages to minimize the thickness of the body about the
passages and thus provide a more resilient wall area around the
passages for accommodating different size wires. Longitudinally
extending grooves 78 are formed in the walls 76 between the
passages to further enhance the flexibility of the material
surrounding the passages.
From the foregoing, it is seen that by the present invention there
is provided unitary connector members which have an interfacial
seal, rear seals, latching arrangement and contact retention means
all integrally formed thereon. Thus, all the necessary features
required for an effective connector are provided in a pair of
unitary bodies of elastic pliant material. These bodies may be
formed by conventional molding techniques. Therefore, it can be
seen that the connector of the present invention may be
manufactured at very low cost and with no assembly procedures
required except the insertion of the contact terminated wires into
the respective contact passages. Moreover, the latter procedure may
be performed without the requirement of a special tool, and the
contacts may be withdrawn from the connector members simply by
pulling on the insulated wires, again without the requirement of a
special tool for releasing the contact retention means.
A connector as illustrated in FIGS. 1 and 2 has been tested to
determine its ability to withstand various temperatures and
climatic conditions. One sample of the connector was temperature
cycled 100 times by subjecting it alternately to -40.degree.C for 1
hour followed by heating the connector to 105.degree.C for 1 hour.
The connector was immersed into water at the end of 11,18,80 and
100 cycles and was subjected to external pressurization of 10 psi.
No leakage was evidenced at this pressure after this temperature
cycling test. Also no electrical failure was observed. Another
sample of the connector was immersed in a 6 inch head of 5% salt
solution at room temperature for 504 hours. No leakage was
evidenced and satisfactory electrical resistance was maintained.
Another sample was immersed in a 4 foot head of 5% salt solution at
room temperature for 164 hours. The connector was then pressure
tested at 10 psi for 10 minutes. This sample also evidenced no
leakage and satisfactory electrical resistance was maintained. Two
samples of the connector were exposed at temperatures of
105.degree.C for 100 hours and no leakage failure was exhibited in
the rear seals of the connectors. Three further samples were
exposed to temperatures of 75.degree.C and 105.degree.C for 120
hours and no leakage failures were observed in the interfacial
seals of the connectors. An additional sample was exposed to oil
vapor at 96.degree.C for 200 hours and no leakage or electrical
failures were observed. Thus, it is seen that the connector of the
present invention is satisfactory for performance on automotive
vehicles or the like wherein environmental conditions may be
encountered which are similar to or less severe than the conditions
created in the aforementioned tests.
Referring now to FIG. 3, there is shown an alternative form of the
connector of the present invention. In this embodiment, the mating
surfaces 38 and 20 on the plug connector member annular section 26
and projection 18, respectively, have a cylindrical rather than a
frusto-conical configuration. The forward inner surface of the
annular section 26 is beveled to provide a frusto-conical lead
surface 80. The outer surface of the projection 18 is also beveled
to provide a frusto-conical lead surface 82 which is complementary
to the surface 80. The surfaces 80 and 82 cooperate to facilitate
insertion of the annular section 26 of the plug connector member
into the recess 24 in the receptacle connector member.
FIG. 4 shows another embodiment of the invention wherein the
interfacial seal 30 is in the form of a lip seal rather than a
labyrinth seal. The lip seal comprises a radially extending axially
and radially resilient lip 84 integrally formed on the bottom of a
recess 85 in the annular section 26 of the plug connector member.
The length of this lip is greater than the distance between the
bottom of the recess and the cylindrical surface 22 of the sleeve
16. Thus, when the connector members are mated, the outer portion
of the lip is caused to be elastically deflected, bending
rearwardly and assuming the position illustrated in FIG. 4. Sealing
is effected by intimate mechanical contact and elastic deformation
of the lip and the receptacle surfaces. Increased external pressure
improves the seal effectiveness by forcing the lip more tightly
against the surface 22. FIG. 5 illustrates a connector having a lip
seal 84 like that illustrated in FIG. 4, except that the lip seal
is positioned forward of the flange 42 on the sleeve 16 when the
connector members are mated.
FIG. 6 illustrates a modified form of a rear seal which may be
utilized in the present invention. The rear seal comprises an
integral inwardly and rearwardly extending resilient lip 86 which
terminates in a cylindrical radially expandable sleeve 88
concentrically disposed within the contact passage 52. The sleeve
88 is dimensioned to have an interference fit with the insulated
wire 60 disposed in the passage. The seal effectiveness increases
with increasing external pressure acting on the external surface of
the sleeve 88 and lip 86. It is noted that the lip 86 must extend
rearwardly rather than forwardly inasmuch as with the latter
increasing external pressure would overcome the elastic forces
causing the seal to leak. The contact 56 in the embodiment
illustrated in FIG. 6 is shown as being an open barrel type
contact. It is important that all the exposed edges of the crimp
barrel of the contact 56, and of the contacts illustrated on in the
other figures of the drawing, be smoothed as by deburring so that
the rear seal 70 will not be scored when the contacts are inserted
into the connector members, which might lead to possible leakage
pathways.
FIG. 7 illustrates a modified form of a contact retention
arrangement which may be utilized in the present invention. In this
embodiment, a longitudinally extending radially resilient finger 90
is integrally formed with the wall of the contact passage 52. A
radially inwardly extending flange element 92 is formed on the end
of the finger 90. This flange element extends into the contact
recess 66 to limit axial movement of the contact within the passage
52. It will be appreciated that due to the resiliency of the finger
90, the flange element 92 will be forced radially outwardly when
the contact 56 is inserted into or withdrawn from the passage
52.
It will be appreciated that the various forms of interfacial and
rear seals disclosed herein may be utilized in the connector of the
present invention in any combination. For example, the rear lip
seal illustrated in FIG. 6 could be used in place of the rear
labyrinth seal in the connector illustrated in FIG. 1. In addition,
either of the interfacial lip seals illustrated in FIGS. 4 and 5
may be substituted for the interfacial labyrinth seal in the
connector illustrated in FIG. 1. Also, for example, either of the
interfacial lip seals illustrated in FIGS. 4 and 5 could be added
in combination with the labyrinth interfacial seal 30 in the
connector illustrated FIG. 1. Other combinations and modifications
will be apparent to those skilled in the art.
* * * * *