Note: Descriptions are shown in the official language in which they were submitted.
10577~1
1 This invention relates to a coupler for tubing and will
have specific, but not limited, application to a coupler for
flexible tubing.
Couplers have long been utilized to secure metallic tubing,
such as copper, to other tubing or to a fitting. In recent
years non-metallic tubing of a generally rigid nature, such as
that formed from polyvinylchloride, has been utilized in place
of the copper or similar metallic tubing. In connecting such
generally rigid non-metallic tubing, the couplers of the prior
art performed in a generally satisfactory manner. With the
development of flexible, non-metallic tubing, such as that formed
from polybutylene, it was found that the prior art type couplers
would not perform satisfactorily when the flexible tubing was
used at elevated temperatures and pressures. As the non-
metallic flexible tubing would become heated, such as to
180F, and utilized at pressures such as between 180 and 220
p.s.i., the tubing would soften and slip from its coupler.
With the following described invention a coupler has been
developed which will not only serve to couple metallic and non-
metallic substantially rigid tubing but also flexible tubingwhich can be used at elevated temperatures and pressures with-
out slipping or becoming disconnected from its coupler.
The coupler of this invention includes a housing having a
bore through it. In the housing bore, located between spaced
shoulders, are seal means, spacer means and locking ring means.
The locking ring means includes a flexible inner frusto conical
part which terminates in an annular tube contacting edge. The
spacer which is rigid contacts the frusto conical portion of the
ring means and serves as a guide when the tube is inserted into
the coupler and through the spacer and ring means with the
seal means which is resilient engaging both the tube and coupler
housing. When the tube is pressurized with a fluid, the spacer
and ring means cooperate in such a manner that the frusto
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1(~577~
1 conical portion of the ring means is flexed toward the tubing
into a flexed generally transverse position with its annular
tube contacting edge being forced into firm locking engagement
with the tubing so as to prevent the tubing from being with-
drawn from ths coupler housing even when the tubing is softened
by being subjected to fluid of an elevated temperature.
The seal means is formed by both a flexible lip which
enhances its sealing characteristics and an o-ring portion which
serves to prevent leakage into the tube when a negative pressure,
such as a vacuum, is maintained within the tube.
Accordingly, it is an object of this invention to provide
a coupler for flexible tubing.
Another object of this invention is to provide a connector
of simple and reliable operation for tubing of both the rigid
and flexible type.
Still another object of this invention is to provide a
coupler of reliable operation for flexible tubing which is sub-
jected to high operating temperatures and pressures.
And still another object of this invention is to provide a
method by which tubing may be joined to a coupler.
Other objects of this invention will become apparent upon
a reading of the invention's description.
Fig. 1 is an exploded view of the component parts of the
coupler of this invention shown in perspective form and with
portions broken away for purposes of illustration.
Fig. 2 is a perspective view of one embodiment of the
coupler in assembled form and having tubing connected thereto
with a portion of the coupler and tubing shown in sectional
form for purposes of illustration.
Fig. 3 is an end view of the coupler of Fig. 2 shown
without the tubing.
Fig. 4 is a longitudinal sectional view of the coupler of
Fig. 2 ~howing the tubing in an unpressurized form.
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-~ 105 ~ ~9~
1 Fig. 5 is a longitudinal sectional view of the coupler of
Fig. 2 showing the tubing in a pressurized condition.
Fig. 6 is a sectional view of a modified embodiment of the
coupler showing tubing inserted therein in unpressurized form.
Fig. 7 is a longitudinal sectional view of the coupler of
Fig. 6 shown with the tubing in pressurized form.
Fig. 8 is a longitudinal sectional view of still another
embodiment of the coupler showing tubing inserted therein in
unpressurized form.
Fig. 9 is a longitudinal sectional view of the coupler of
Fig. 8 shown with the tubing in pressurized form.
The preferred embodiments illustrated are not intended to
be exhaustive or to limit the invention to the precise forms
disclosed. They are chosen and described in order to best ex-
plain the principles of the invention and its application and
practical use to thereby enable others skilled in the art to
best utilize the invention.
The couplers illustrated in the figures include a housing
having a body part 10 and a cap part 12. The housing of the
coupler may be of a unitary construction, although,as shown in
the illustrated embodiments, it is preferred for the housing to
have a body part 10 fitted with a cap part 12 for ease of
assembly of the coupler. The coupler housing has a central
through bore 14. One end of body part 10 is internally threaded
within bore 14 so as to receive an interconnecting threaded pipe
or fitting 16. An annular shoulder 18 protrudes into bore 14
approximately mid-way between the ends of body part 10. Bore
14 at the opposite end of body part 10 is of an expanded
dimension so as to form an annular shoulder 20 in the side wall
of the bore. Cap part 12 of the housing is fitted into the
expanded end of bore 14 and attached, such as by an adhesive or
spin welding, to body part 10. The inner end of cap part 12
forms a beveled annular shoulder 22 within housing bore 14.
1~5~7791
1 Shoulders 20 and 22 are opposed and in conjunction with side
wall 24 of the expanded portion of bore 14 serve to define an
annular groove within the coupler housing. Body part 10 and
cap part 12 of the coupler housing may be formed of a metallic
machined or cast material or of a molded plastic composition.
An annular resilient seal 26, an annular rigid spacer 28
and a lock ring 30 are located within the interior of the coupler
housing between shoulders 20 and 22 and in substantial coaxial
alignment with housing bore 14. Seal 26, which may be of a
rubber material, includes a flexible cup-defining lip portion
32 and an O-ring portion 34. Spacer 28 is of a rigid material,
such as hardened plastic, and includes a flattened edge 36 and
a rounded edge 38. Lock ring 30 is of a spring steel construction
and includes a frusto conical portion 40 and a flange portion
42. The angle between frusto conical portion 40 and flange
portion 42 of the ring without the tube inserted is preferably
between 45 and 55 degrees. The frusto conical portion 40 of
ring 30 is formed by a plurality of radially spaced flexible
tabs 44 which cooperate at their free ends to define a tube
contacting inner edge 46.
In the embodiment of the coupler shown in Figs. 1-5 seal
26 is positioned adjacent shoulder 20 with its lip portion 32
contacting side wall 24 of housing bore 14. Spacer 28 is
located next to seal 26 with its flattened edge 36 adjacent
O-ring portion 34 of the seal. Lock ring 30 is positioned
next to spacer 28 with its frusto conical portion 40 positioned
adjacent shoulder 22 of the housing and preferably in contact
with the rounded edge 38 of the spacer. Flange portion 42 of
ring 30 contacts side wall 24 of bore 14 and preferably abuts a
small locating shoulder 48 formed in the side wall. The in-
ternal diameter of seal 26 as measured across its 0-ring portion
34 and the internal diameter of lock ring 30 as measured across
inner edge 46 of its frusto conical portion 40 is slightly less
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105 77~31
1 than the diameter of the tube receiving part of bore 14 to
enable the seal and ring to make sliding engagement with tube
50 as it is inserted into the coupler housing.
To utilize the coupler above described, tube 50 having
an external diameter which is slightly less than the diameter
of housing bore 14 but which is slightly greater than the inner
diameters of seal 26 and lock ring 30 is inserted into bore 14
through cap part 12. Tube 50 first contacts inner edge 46 of the
frusto conical portion 40 of ring 30 which slides over the tube
surface and serves as a guide as the tube advances through
spacer 28 and seal 26 and abuts shoulder 18 within housing body
part 10 at its end 50. The inner diameter of spacer 28 exceeds
the external diameter of tube 50 so as not to interfere with
the insertion of the tube into housing bore 14. With tube 50
fully inserted into bore 14, o-ring portion 34 of the seal and
inner edge 46 of ring frusto conical portion 40 peripherally
contact the tube.
Upon the introduction of a fluid, either in liquid or
gaseous form, into tube 50 to cause its pressurization, a
portion of the fluid passes between tube end 52 and shoulder 18
of the housing body part, along bore 14 between the tube and
housing body part and into the area between shoulder 20 and
seal 26. This causes tube 50 to be pushed away from housing
shoulder 18 and seal 26 to be urged toward cap part 12 with
spacer 28 being forceably pressed against the flexible frusto
conical portion 40 of lock ring 30. The force imposed by
spacer 28 against lock ring 40 causes the lock ring to be
straightened into a general ttansverse orientation, abutting
shoulder 22 within the coupler housing. As frusto conical
portion 40 of the lock ring 30 is straightened into its trans-
verse position, inner edge 46 of the ring bites deeper into
tube 50 as shown in Fig. 5 to firmly lock the tube within the
coupler. This biteof inner edge 46 of lock ring 30 into
`` lOS~'7~1
1 tube 50 is sufficient to retain the tube, which may be formed
of polybutylene, within the coupler even when the temperature
of the fluid passing through the tube is sufficiently high so
as to cause the tube to become quite pliable.
Further bending or inversion of frusto conical portion
40 of the lock ring is prevented due to its abutment with
shoulder 22 of the coupler housing. It is to be understood
that during pressurization of tube 50 the straightening of ring
frusto conical portion 40 occurs very rapidly with spacer 28
serving the function of applying a uniform circumferential force
to the frusto conical portion to cause a uniform bite of inner
edge 46 of the ring into tube 50. Lip portion 32 of seal 26
forms a cup-shaped seal end edge which prevents any fluid from
leaking past the seal, around the spacer, through the lock ring
and out cap part 12 of the coupler.
The embodiment of the coupler shown in Figs. 6 and 7 is
substantially similar to that described for the coupler
illustrated in Figs. 1-5, with the exception that the order of
assembly of seal 26, spacer 28 and lock ring 30 between
shoulders 20 and 22 within the coupler housing is reversed.
Also shoulder 22 of cap part 12 is flattened and edge 36 of
spacer 38 is beveled. Lock ring 30 is positioned adjacent
shoulder 20 with seal 26 being positioned adjacent shoulder 22
and spacer 28 being located between the lock ring and seal.
During insertion of tube 50 into this embodiment of the
coupler, the tube does not engage inner edge 46 of frusto
conical portion 40 of lock ring 30 until it is past seal 26.
In this arrangement of the lock ring, spacer and seal within
the coupler housing, tube 50 can be inserted into the coupler
and through seal 26 before contacting ring 30, thus allowing
only its distal end to be scraped by the ring, while that portion
of the tube encircled by seal 26 remains unmarred by the lock
ring to allow a more even area of contact between the tube
~057~
1 and the seal.
In Fig. 6 the tube is shown in unpressurized form. When
pressurized fluid is introduced into tube 50, the tube will be
urged slighly away from shoulder 18 in housing body part 10
and tube contacting frusto conical portion 40 of lock ring 30
will be shifted with the tube into its general transverse tube-
engaging position shown in Fig. 7, causing the tube to be more
firmly locked within the coupler. Inversion of frusto conical
portion 40 of the lock ring is prevented by its abutment with
beveled edge 36 of spacer 38. Additionally, the rounded edge
38 of the spacer will enter the cup formed by lip portion 32 in
seal 26, causing the seal to be more firmly wedged into seal-
ing engagement between the coupler housing and tube 50. In
this embodiment it is important that lock ring frusto conical
portion 40 be constructed so as to shift uniformly and rapidly
from its beveled position shown in Fig. 6 into its firmly
interlocking position shown in Fig. 7 upon the pressurization
of tube 50.
In the embodiment of this invention shown in Figs. 8
and 9, lock ring 30, spacer 28 and seal 26 are positioned in
a similar manner between housing shoulders 20 and 22 as in the
embodiment in Figs. 6 and 7, with the addition of a resilient
o-ring seal 54 introduced between shoulder 20 and frusto
conical portion 40 of the lock ring. Additionally, it is also
preferable that a slight shoulder 56 be formed in side wall
24 of housing body part 10 for the purpose of seating lock ring
30. In Fig. 8 the coupler is shown with tube 50 in its un-
pressurized form. Upon pressurization of the tube, such as by
the introduction of pressurized fluid, the tube is urged
slightly away from internal housing shoulder 18 with the fluid
contacting seal 54 in front of shoulder 20 to cause the seal to
be urged against the frusto conical portion 40 of lock ring 30.
The pressure of seal 54 causes frusto conical portion 40 to be
l~S77~1
1 urged into its general transverse interlock position with tube
50 as shown in Fig. 9. In this manner seal 54 functions
similarly to seal 26 in the embodiment shown in Figs. 4 and
5, causing a generally uniform bending pressure to be applied
circumferen~ially about lock ring 30. The inversion of the
lock ring frusto conical portion 40 past its tube interlock
position is prevented by its abutment with beveled edge 38 of
spacer 28. Seal 26 is wedged into its sealing position between
the coupler housing and tube in a manner like that described
for the embodiment in Figs. 6 and 7.
~! In each of the above described embodiments of the coupler
of this invention it is the rapid but controlled movement of
the frusto conical portion 40 of lock ring 30 into firm biting
engagement with the outer surface of the inserted tube with the
lock ring being prevented from complete inversion which causes
the tube to be fixedly secured within the coupler. Although
lock ring portion 40 could be stopped by cap part 12 or spacer
28 at a right angular tube engaging position, it is preferable
to have portion 40 engage the inserted tube at a forward angle,
such as between five and thirty degrees, depending upon the
size of the coupler and tube material, when shifted into its
generally transverse orientation. This serves to strengthen
the holding power of the lock ring. By constructing seal 26
with an o-ring portion in conjunction with a cup-defining lip,
the coupler of this invention serves also to seal the inter-
fitting tube against leakage during negative pressure situa-
tions. Also in the embodiment of Figs. 1-5, spacer 28 prevents
seal 26 from creeping around and between lock ring tabs 44
and perhaps lifting the tabs from tube engagement when soft-
ened at elevated operating temperatures and pressures.
It is to be understood that the invention is not to belimited to the details above given but may be modified within
the scope of the appended claims.
_g_
``' 1~57791
SUPPLEMENTARY DISCLOSURE
The embodiment of the coupler shown iD Figs. 10-13 is used to
~oin two like tubes 50 together and includes two sets of cooperating seals
26, spacers 28 and lock rings 30. Each seal, spacer and lock ring set
operates in its tube gripping function substantially similar
to the seal, spacer and lock ring in the embodiment of the coupler
illustrated in Figs. 6 and 7. Body part 10 includes a pair of tubular
mandrel parts 58 which are concentric with body part bore 14 and which
extend integrally from shoulders 18. When a tube 50 is inserted into one
end of body part 10 it fits snugly over the mandrel part 58 therein with
end 52 of the tube abutting a shoulder 18. In this manner each mandrel
part 58 serves as a means for centering the tubing as it is inserted into
the coupler. This embodiment of body part 10 may be provided with a con-
tinuous offset annular shoulder 20 as described in the previous embodi-
ments, or, as illustrated, may include a plurality of circumferentially
spaced, radially disposed ribs 60 whose end faces 62 cooperate to form a
shoulder which is functionally similar to shoulder 20 of the other embodi-
ments. Ribs 60 are utilized in the embodiment of Figs. 10-13 instead of
a solid annular shoulder for the purpose of conserving the amount of
material used in body part 10.
A lock ring 30 is positioned next to end faces 62 of ribs 60
with a seal 26 being positioned next to shoulder 22 of each cap part 12
and a spacer 28 being located between each lock ring and seal. As in the
embodiment of the coupler shown in Figs. 6 and 7, when each tube 50 is
inserted into the coupler the tube does not engage inner edge 46 of frusto
conical portion 40 of lock ring 30 until it i8 past seal 26. In Fig. 11
tubeR 50 are shown in unpressurized form. When pressurized liquid is
A
lOS7791
introduced into tubes 50, the tubes will be urged slightly away from
shoulders 18 of housing body part 10 and tube-contacting frusto conical
portion 40 of each lock ring 30 will be shifted with its encircled tube
into a general transverse tube-engaging position as shown in Fig. 12,
causing the tubes to be more firmly locked within the coupler. Inversion
of frusto conical portion 40 of each lock ring is prevented by lts abutment
with bevelled edge 36 of the ad~acent rigid spacer 28. ~ounded edge 38 of
each spacer will enter the cup formed by lip portion 32 of ad~acent seal
26 to cause the seal to be more firmly wedged into sealing engagement
between the coupler housing and its encircled tube.
A mandrel p~rt 58, and, if desired, ribs 60 shown in the coupler
embodiment of Figs. 10-13, can be incorporated into each of the coupler
embodiments previously described for use with the threaded portion of bore
14. In such couplers a tube 50 can be joined to a threaded fitting or
pipe.
As in the case of the originally described embodiments of the
coupler of this invention, it is the rapid but controlled movement of the
frusto conical portion 40 of lock ring 30 into firm biting engagement with
the outer surface of the inserted tube with the lock ring being prevented
from complete inversion which causes the tube to be fixedly secured within
the coupler. Although lock ring portion 40 could be stopped by cap part
12 or spacer 28 at a right angular tube-engaging position, it is preferable
to have portion 40 engage the inserted tube at a forward angle, such as
between five and thirty degrees, depending upon the si~e of the coupler
and tube material, when shifted into its generally transverse orientation.
This serves to strengthen the holding power of the lock ring. By con-
structing seal 26 with an 0-ring portion in conjunction with a cup-defining
lip, the coupler of this invention serves also to seal the interfitting
tube against leakage during negative pressure situations.
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