U.S. patent application number 09/248612 was filed with the patent office on 2002-05-30 for disconnect coupling.
Invention is credited to OSE, PAUL N..
Application Number | 20020063426 09/248612 |
Document ID | / |
Family ID | 22939872 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020063426 |
Kind Code |
A1 |
OSE, PAUL N. |
May 30, 2002 |
DISCONNECT COUPLING
Abstract
A disconnect coupling for high pressure fluidic lines has an
improved retaining mechanism for retaining the male portion within
the female portion. The mechanism comprises a plurality of
retaining lugs that are disposed within the female portion of the
coupling. The retaining lugs are arranged so as to mate with a
retaining groove formed into the outer surface of the male portion
such that the bearing surfaces contact each other over a
much-increased surface area.
Inventors: |
OSE, PAUL N.; (RAMSEY,
MN) |
Correspondence
Address: |
CONRAD A HANSEN
MOORE & HANSEN
2900 NORWEST CENTER
90 SOUTH SEVENTH STREET
MINNEAPOLIS
MN
55402
|
Family ID: |
22939872 |
Appl. No.: |
09/248612 |
Filed: |
February 11, 1999 |
Current U.S.
Class: |
285/316 |
Current CPC
Class: |
F16L 37/0841
20130101 |
Class at
Publication: |
285/316 |
International
Class: |
F16L 037/18 |
Claims
What is claimed is:
1. A disconnect coupling connectable to high pressure fluidic lines
comprising: a female portion connectable to a fluidic line and
having a longitudinal axis and a housing, a fluid flow channel
extending through said housing and positioned along said axis; a
male portion connectable to a fluidic line, said male portion
having a longitudinal axis and being receivable within said channel
of said female portion for releasable connection to said female
portion, said male portion having a fluid flow passage extending
through said male portion and along said male portion axis, said
passage positioned to communicate with said channel of said female
portion when said male portion is received within said female
portion; and a retaining mechanism for quickly connecting and
disconnecting said male and female portions, said retaining
mechanism comprising: a plurality of retaining lugs moveably
mounted within said housing of said female portion, said lugs
movable between a locking position, wherein said lugs extend within
said channel to engage said male portion, and a release position,
wherein said lugs are substantially retracted within said housing
of said female portion; a retaining groove formed in said male
portion and positioned to receive said retaining lugs when said
male portion is connected to said female portion and said lugs are
in said locking position, said retaining groove including a first
bearing surface; each said retaining lug having a bearing surface
substantially congruent to said bearing surface of said retaining
groove; and a collar slidably mounted on said female portion for
movement between a first position, wherein said retaining lugs are
lockably retained in said locking position, and a second position
wherein said retaining lugs may move between said locking position
and said release position.
2. The disconnect coupling of claim 1 wherein said bearing surfaces
of said lugs and said bearing surface of said retaining groove are
in substantially full facial contact when said male and female
portions of said coupling are connected and said lugs are retained
in locking position in said retaining groove by said collar.
3. The disconnect coupling of claim 2 wherein said bearing surface
of each said retaining lug has surface geometry which is
substantially congruent to a frustum of a right circular cone
having an axis of symmetry that substantially coincides with said
longitudinal axis of said female portion and wherein said bearing
surface of said retaining groove is annular and has substantially
the surface geometry of a section of a frustum of a right circular
cone having an axis of symmetry that coincides with said
longitudinal axis of said male portion.
4. The disconnect coupling of claim 3 wherein said collar has a
substantially cylindrical inner surface and each said retaining lug
has a base provided with a cylindrical surface, said collar inner
surface being substantially congruent with and in substantially
full facial contact with said base cylindrical surface of each said
retaining lug when said retaining lugs are retained in said locking
position by said collar.
5. The disconnect coupling of claim 4 wherein said bearing surface
of each said lug spans an arc of between 30 and 60 degrees of the
circumference of said annular bearing surface of said retaining
groove.
6. The disconnect coupling of claim 5 wherein each of said
retaining lugs further includes a second bearing surface, each said
second bearing surface having the surface geometry of a section of
a frustum of a right circular cone.
7. The disconnect coupling of claim 6 wherein a second bearing
surface is positioned on said retaining groove, said second bearing
surface of said retaining groove having the surface geometry of a
frustum of a right circular cone.
8. The disconnect coupling of claim 7 wherein said bearing surface
of each of said retaining lugs and said bearing surface of said
retaining groove are inclined no more than 30.degree. from a plane
normal to the respective longitudinal axes of said male and female
portions of said coupling.
9. The disconnect coupling of claim 8 wherein said bearing surface
of each of said lugs and said bearing surface of said retaining
groove are inclined no more than 20.degree. from a plane normal to
the respective longitudinal axes of said male and female portions
of said coupling.
10. The disconnect coupling of claim 9 wherein said bearing
surfaces of said plurality of said retaining lugs collectively span
no more than a total of 180.degree. of the angular circumference of
said retaining groove.
11. The disconnect coupling of claim 10 wherein said plurality of
said retaining lugs are arranged symmetrically around the
circumference of said retaining groove.
12. The disconnect coupling of claim 11 wherein the number of said
retaining lugs is an even number.
13. The quick disconnect coupling of claim 1 wherein said bearing
surface of said retaining groove is annular, and said bearing
surface of each said lug spans an arc of between 30 and 60 degrees
of the circumference of said annular bearing surface of said
retaining groove.
14. The quick disconnect coupling of claim 13 wherein said bearing
surface of each said lug spans an arc of between 40 and 50 degrees
of the circumference of said annular bearing surface of said
retaining groove.
15. The quick disconnect coupling of claim 14 wherein said bearing
surface of each said lug spans an arc of substantially 45 degrees
of the circumference of said annular bearing surface of said
retaining groove.
16. The disconnect coupling of claim 1 wherein each of said
retaining lugs further includes a second bearing surface, each said
second bearing surface having the surface geometry of a section of
a frustum of a right circular cone.
17. The disconnect coupling of claim 16 wherein a second bearing
surface is positioned on said retaining groove, said second bearing
surface of said retaining groove having the surface geometry of a
frustum of a right circular cone.
18. The disconnect coupling of claim 1 wherein said bearing surface
of each of said retaining lugs and said bearing surface of said
retaining groove are inclined no more than 30.degree. from a plane
normal to the respective longitudinal axes of said male and female
portions of said coupling.
19. The disconnect coupling of claim 1 wherein said bearing surface
of each of said lugs and said bearing surface of said retaining
groove are inclined no more than 20.degree. from a plane normal to
the respective longitudinal axes of said male and female portions
of said coupling.
20. The disconnect coupling of claim 1 wherein said bearing surface
of said retaining groove is annular and said bearing surfaces of
said plurality of said retaining lugs collectively span no more
than a total of 180.degree. of the angular circumference of said
retaining groove.
21. The disconnect coupling of claim 1 wherein said bearing surface
of said retaining groove is annular and said plurality of said
retaining lugs are arranged symmetrically around the circumference
of said retaining groove.
22. The disconnect coupling of claim 1 wherein the number of said
retaining lugs is an even number.
23. The disconnect coupling of claim 1 wherein said bearing surface
of said retraining groove is annular and said bearing surfaces of
said plurality of said retaining lugs collectively span at least
180 degrees of the angular circumference of said retaining
groove.
24. The quick disconnect coupling of claim 1 wherein the area of
surface contact between said bearing surface of each said retaining
lug and said bearing surface of said retaining groove is at least
0.1 square inch.
25. The disconnect coupling of claim 1 wherein each said retaining
lug includes a body whose cross section is a radial section of a
right cylindrical ring.
26. The disconnect coupling of claim 1 wherein said female portion
includes a plurality of apertures for slidably receiving said
retaining lugs, each said aperture including a pair of shoulders
therein, each said retaining lug including a base, and each said
base including a pair of lips constructed and arranged to be
congruent with and to contact said pair of congruent shoulders of a
said aperture.
27. The disconnect coupling of claim 26 wherein each of said
retaining lugs has a pair of spaced apart substantially planar
sides and each said aperture has a pair of substantially planar
inner surfaces, said planar sides of each said retaining lug being
in substantially full facial contact with the substantially planar
inner surfaces of each said aperture.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is directed to a disconnect coupling,
and more specifically, to an improved apparatus for retaining a
male portion of a disconnect coupling within a bore of a female
portion of a disconnect coupling.
[0002] Disconnect couplings, commonly referred to as
quick-disconnect couplings, are highly desirable for use in both
hydraulic and pneumatic applications. Furthermore, in certain
specialized applications it is essential that a quick disconnect
coupling be capable of withstanding extremely high pressures in the
lines being connected through the coupling. In hydraulic
applications, for example, it is possible for the pressures applied
to a coupling to exceed 60,000 pounds per square inch.
[0003] The state of the art disconnect coupling utilizes a
plurality of generally spherical ball bearings secured within the
female portion of the coupling that are releaseably received in a
retaining groove formed in a male portion of the disconnect
coupling to securely retain the male portion of the coupling within
the female portion of the coupling. This type of disconnect
coupling functions acceptably where moderate pressures are applied
across the disconnect coupling. However, under higher pressures
ball bearing type disconnect couplings can fail due to deformation
of the bearing surfaces within the retaining groove in the male
portion of the coupling. Because the spherical ball bearings of
this type of coupling contact the bearing surface of the retaining
groove in the male portion of the coupling at a very small area
which can almost be characterized as a single point, these ball
bearings will subject the bearing surface of the retaining groove
to point stresses which regularly exceed the ultimate strength of
the material of the male portion of the coupling. Deformation of
the bearing surface of the retaining groove makes it more likely
that the male and female portions of the coupling will fail to
properly engage one another. In addition, ball bearings in ball
bearing type disconnect couplings tend to translate a
disproportionately large amount of the longitudinal forces applied
across the ball bearings and retaining groove into radial forces
directed in a normal direction relative to the longitudinal axis of
the coupling and applied to the female portion of the disconnect
coupling. Repeated application of these radially outwardly directed
forces to the female portion of the coupling may deform or even
shatter the female portion of the coupling.
[0004] One solution to the problems associated with ball bearing
type disconnect couplings presently on the market, has been the
utilization of a female portion having a retaining means with a
curved surface which contacts the bearing surface in the retaining
groove on the male portion of the coupling along an arc. Increasing
the amount of contact between the retaining means and the bearing
surface of the retaining groove of the male portion of the coupling
helps to decrease the magnitude of the stresses applied to the
bearing surface of the male portion. However, the area of contact
is a line and is still relatively small; therefore the stresses
applied to the bearing surfaces can exceed the ultimate strength of
the material from which the bearing surface of the male portion is
fabricated. In addition, the curved surface of the retaining means,
like the curved surface of the ball bearing, directs an
unacceptably high amount of force in an outward radial direction
into the female portion of the coupling.
[0005] Therefore, it is an object of the invention to provide a
structure for a retaining mechanism that will impart substantially
lower stresses to the bearing surfaces of the male portion of the
coupling. It is also an objective of the present invention to
provide a structure for a retaining mechanism which minimizes the
magnitude of the radial forces applied to the female portion of the
coupling. A last objective of the present invention is to provide a
structure for a retaining mechanism having a large cross-sectional
area for resisting shear stresses and which is capable of evenly
distributing applied shear stresses around the bearing surfaces of
the retaining groove of the male portion of the coupling.
SUMMARY OF THE INVENTION
[0006] The present invention comprises a disconnect coupling that
is connectable to high pressure fluidic lines. The coupling of the
present invention has a female portion with a means for connecting
it to a fluidic line. The female portion has a housing with a
longitudinal axis and a fluid flow channel formed therethrough
along the longitudinal axis. The coupling also has a male portion
which also has means for connecting it to a fluidic line. The male
portion of the coupling is receivable within the channel of the
female portion. In addition, the male portion has a fluid flow
passage formed therethrough along a longitudinal axis, with the
passage positioned so as to communicate with the channel of the
female portion when the male and female portions are connected.
[0007] A retaining mechanism for quickly connecting and
disconnecting the male and female portions is provided and
comprises a plurality of retaining lugs that are moveably mounted
within the housing of the female portion so as to be capable of
engaging the male portion of the coupling. The retaining lugs are
slidably movable between a locking position, wherein the lugs
extend within the channel to engage the male portion, and a release
position, wherein the lugs are substantially retracted within the
housing of the female portion so as to permit placement or removal
of the male portion of the coupling in or from the channel of the
female portion of the coupling.
[0008] A retaining groove is formed around the male portion and is
positioned so as to receive the retaining lugs when the male
portion is connected to the female portion and the lugs are in
their locking position. Of importance here is that both the
retaining groove and the retaining lugs have bearing surfaces that
are congruent to one another. A collar is slidably mounted on the
female portion of the coupling and is moveable between a first
position, wherein the collar lockably maintains the retaining lugs
in their locking position, and a second position wherein the collar
permits the retaining lugs to be moved to their release
position.
[0009] It is preferred that the bearing surfaces of the retaining
lug and of the retaining groove have substantially the same surface
geometry as a frustum of a right circular cone. In this case, the
right circular cone which defines the bearing surfaces of the
preferably annular retaining groove and the retaining lugs has an
axis of symmetry that coincides with the longitudinal axes of the
female and male portions of the coupling. The shape of the
respective bearing surfaces of the retaining lugs and retaining
groove permits substantially full facial contact therebetween when
the male and female portions of the coupling are connected and the
retaining lugs are lockably retained in the retaining groove by the
collar.
[0010] The retaining lug of the present invention has a body with a
tip and a base, with the base being received within the female
portion of the disconnect fluid coupling. The tip of the retaining
lug has at least one bearing surface formed thereon, with the
bearing surface being arranged and constructed to mate with a
congruent bearing surface that is formed in male portion of the
disconnect fluid coupling. The respective bearing surfaces of the
tip of the retaining lug and the male portion of the coupling
define an area of contact that has a substantial surface area.
[0011] The inner and outer bearing surfaces of the retaining lug
are inclined at an angle of no more than 30 degrees as measured
from a plane perpendicular to the longitudinal axis of the
disconnect coupling. Preferably the inner and outer bearing
surfaces of the retaining lug are angled at approximately 20
degrees as measured from a plane perpendicular to the longitudinal
axis of the disconnect coupling.
[0012] The retaining lug according to the present invention takes
the shape of a radial section of a right cylinder and preferably
has bearing surfaces that have the geometric shape of the surface
of a section of a frustum of a right circular cone. The base the
retaining lug generally also has a lip formed thereto which
prevents the lug from sliding into the channel of the female
portion of the disconnect fluid coupling. Each retaining lug may
span between 30 and 60 degrees of the circumference of the annular
bearing surface of the retaining groove. However, it is preferred
that the retaining lugs span no more than 45 degrees of the
circumference of the channel of the housing of the female portion.
Furthermore, it is also preferred that each lug have at least one
bearing surface that is at least 0.1 square inches in area.
[0013] These and other objectives and advantages of the present
invention will become apparent from the following detailed
description and illustrative drawings when read in conjunction with
the appended claims.
DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of a disconnect coupling
embodying the invention and illustrating the male and female
portions of the coupling and their relation to one another.
[0015] FIG. 2 is a side elevational view of the coupling of FIG. 1
wherein the male portion, or nipple, of the coupling is seated
within the female portion of the coupling.
[0016] FIG. 3 is an exploded view of the female portion of the
coupling of FIG. 1 showing all of the component parts of the female
portion of the coupling and their relation to each other.
[0017] FIG. 4 is a cross sectional view of the female portion of
the fully assembled coupling taken along cutting plane 4-4 of FIG.
1.
[0018] FIG. 5 is a cross sectional view of the male portion of the
coupling and a partial cross sectional view of the female portion
of the coupling illustrating the relationship of the exterior
contours of the male portion of the coupling to the interior
contours of the female portion of the coupling.
[0019] FIG. 6 is a cross sectional view of the coupling wherein the
male portion of the coupling is received and retained within the
female portion of the coupling.
[0020] FIG. 7 is a perspective view of a retaining lug embodying
the invention.
[0021] FIG. 8 is a cross sectional view of a retaining lug taken
along cutting line 8-8 of FIG. 7.
[0022] FIG. 9 is an end view of the arrangement of the respective
retaining lugs, taken in the direction of cutting plane 9-9 of FIG.
6, the retaining lugs being illustrated in a first locked position
in solid lines, and in a second open or release position in
phantom.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Referring to FIGS. 1 and 2, it can be seen that the
disconnect coupling 10 embodying the invention is comprised of two
separate portions, a male portion or nipple 12, and a female
portion 14. Each of the portions 12, 14 will be coupled during
normal use by respective attachment means 13 and 52, to a hydraulic
or pneumatic line (not shown).
[0024] The nipple 12 is arranged to be received within a channel 32
that extends axially through the female portion 14 of the coupling
10. Nipple 12 has a axial passage 32A formed therethrough which
communicates with channel 32 formed through the female portion 14
of coupling 10. The nipple 12 is releaseably retained within the
female portion 14 by a plurality of retaining lugs 20 whose
structure and function will be described in detail below. The
coupling 10 of the present invention may be used to connect fluidic
lines carrying various compressed fluids including air, water and
hydraulic fluids.
[0025] FIGS. 3-6 illustrate the female portion 14 of the coupling
10, which is comprised of a housing 30, a shell 40, a rear cap 50,
a valve seat 60, and a poppet valve assembly 70. The rear cap 50 is
a generally cylindrical structure through which the channel 32
passes. The rear cap 50 also has a hydraulic line attachment means
52 for connecting the female portion 14 of the coupling 10 to a
hydraulic line, and a threaded portion 54 formed on the inner
surface of the rear cap 50 around channel 32. The housing 30 is
also a generally cylindrical structure through which the channel 32
passes. The housing 30 has a threaded portion 34 arranged to be
received within the threaded portion 54 of the rear cap 50. Valve
seat 60 is arranged to be caught between the rear cap 50 and the
housing 30 of the female portion 14 of the coupling 10 so as to
form a tight seal therebetween. Valve seat 60 also has channel 32
extending therethrough. The sealing portion 62 of the valve seat 60
is interposed directly between the end of the housing 30 and a
shoulder 56 formed into the rear cap 50 within the channel 32.
Preferably, the valve seat 60 will be fashioned of a material that
is relatively softer than the materials from which the housing 30
and the rear cap 50 are fabricated so that when the sealing portion
62 of the valve seat 60 is caught between the housing 30 and rear
cap 50, it will be deformed to conform to the shape of the housing
30 and the rear cap 50, thereby forming a tight seal
therebetween.
[0026] The valve seat 60 receives the components of the poppet
valve assembly 70. The poppet 72 has a conical sealing end 72A and
a threaded end 72B. The sealing end 72A of the poppet 72 is
substantially conical and is received against a congruent conical
mating surface 62A of the valve seat 60. The threaded end 72B of
the poppet 72 extends through and out of the valve seat 60 and into
the channel 32 of the housing 30. In order to form a tight seal
between the conical mating surface 62A of the valve seat 60 and the
sealing end 72A of the poppet 72, the conical sealing end 72A of
the poppet 72 is provided with an O ring 73A which is seated in
annular groove 71. Backup ring 73B retains the O-ring 73A in
annular groove 71 of the sealing end 72A of the poppet 72. The
sealing end 72A of the poppet 72 is biased into sealing contact
with the valve seat 60 by spring 74. One end of the spring 74 bears
against a shoulder 66 formed into the valve seat 60 within channel
32 and the other end of the spring 74 bears against a sprocket 76
received onto the threaded end 72B of the poppet 72. Sprocket 76 in
turn bears against a shoulder 77A formed into the poppet actuator
bushing 77. Poppet actuator bushing 77 is received within the
channel 32 of housing 30 and is free to slide longitudinally
between the end of the valve seat 60 and a shoulder 33 formed into
the inner surface of the housing 30. A nut 78 is threaded onto the
threaded end 72B of the poppet 72 so as to retain the sprocket 76
on the poppet 72, and thereby capturing the spring 74 between the
sprocket 76 and the shoulder 66 formed into the valve seat 60.
[0027] The housing 30 also includes an annular sealing slot 35
formed into its inner surface around channel 32. The sealing slot
35 has contained therein an O-ring 35A and a backup ring 35B which
retains the O-ring within the sealing slot 35. O-ring 35A acts to
form a seal around the nipple 12 when the nipple 12 is received
within the channel 32 of the housing 30.
[0028] When the nipple 12 is inserted into the channel 32 of the
housing 30 as illustrated in FIGS. 5 and 6, the end 12A of the
nipple 12 bears against the poppet actuator bushing 77, forcing
poppet 72 to slide longitudinally within the channel 32 toward the
rear cap 50, and in doing so, breaking the seal between the O-ring
73A and the conical mating surface 62A of the valve seat 60 (FIG.
6) to allow compressed hydraulic fluid to flow past the sealing end
72A of the poppet 72 in direction 79, passing through openings
around sprocket 76. When nipple 12 is fully received with the
female portion 14 of the coupling 10, hydraulic fluids may pass
through channel 32 to passage 32A and vice versa. The nipple 12 and
the housing 30 are arranged such that when the end 12A of the
nipple 12 has opened the poppet valve assembly 70. An annular
retaining groove 18 formed into the nipple 12 is simultaneously
aligned to receive a plurality of retaining lugs 20 disposed around
the inner surface of the housing 30. Retaining lugs 20 are biased
by collar 40 into the retaining groove 18 of the nipple 12 so as to
couple the male portion 12 of the coupling 10 to the female portion
14. In this coupled state, the coupling 10 may conduct compressed
or pressurized fluids therethrough.
[0029] The retaining lugs 20 are disposed within a plurality of
apertures 36 formed through the housing 30 adjacent the front end
of the housing. In the preferred embodiment of the present
invention, the apertures 36 are symmetrically arranged around the
channel 32 and extended radially outward through the cylindrical
wall of the housing 30. In addition, it is preferred to have an
even number of apertures 36 formed into the housing 30.
Accordingly, the preferred embodiment of the present invention
comprises four retaining lugs 20. Furthermore, it is preferred that
the total combined arc length of the apertures 36 formed into the
of the housing 30 span approximately 180 degrees of the
circumference of the channel 32. In the preferred embodiment of the
present invention, the total combined arc length of the apertures,
and hence of the retaining lugs 20, is 180.degree., each retaining
lug 20 of the preferred embodiment spanning 45.degree.. It must be
understood, however, that so long as the symmetry of the
arrangement of the apertures 36, and hence the arrangement of the
retaining lugs 20, is maintained, there may be formed into the
housing 30 an odd number of apertures 36. Likewise, the apertures
36 formed through the housing 30 and associated retaining lugs 20
may span more or less than 180 degrees of the circumference of the
channel 32 formed through the housing 30 depending upon the
particular nature of the application for which the coupling 10 is
intended. For example, with suitable structural variations in the
housing 30 to maintain the structural integrity of the coupling 10,
the retaining lugs 20 may span between 30 and 60 degrees of the
circumference of the channel 32. Numerous variations in the number
and in the angular span of the apertures 36 within the housing 30
and retaining lugs 20 are suitably functional and are within the
purview of the present invention.
[0030] As each of the retaining lugs 20 are substantially
identical, only one of the retaining lugs 20 will be described in
detail. Referring now to FIGS. 7, 8 and 9 it can be seen that the
retaining lug 20 is essentially a radial section of a right
cylindrical ring, having a tip 22 and a base 24. The tip 22 of the
retaining lug 20 is chamfered to create an inner bearing surface
22A and an outer bearing surface 22B. The retaining lug 20 also
includes a pair of lips 24A formed integral with the base 24
thereof.
[0031] The lips 24A of the preferred embodiments of the retaining
lug 20 have a substantially cylindrical under surface. Each of the
apertures 36 in the housing 30 extends entirely through the wall of
the housing 30 and further includes a pair of recessed shoulders
36A sized to receive the lips 24A of the retaining lug 20 so that
base 24 may be positioned flush with the outer surface of the
housing 30 when the collar 40 is in a locking position.
[0032] Collar 40 is received over the housing 30 and is
longitudinally slidable over the housing 30 between a first,
locking position indicated in FIG. 2 at 40 and a second, release
position indicated at 40'. The collar 40 is normally biased into
its locking position by a spring 42 disposed between the collar 40
and the housing 30 as illustrated in FIG. 6. In the locking
position, the collar 40 forces the retaining lugs 20 into their
respective apertures 36 such that the base 24 of each retaining lug
20 are substantially flush with the outer surface of the housing 30
and such that the tip 22 of each retaining 20 is fully extended
into the channel 32 formed through the housing 30. When the collar
40 is moved away from the rear cap 50 to its open position, 40',
the retaining lugs 20 are free to travel radially outward away from
the channel 32 of housing 30 to their release position as indicated
at 20' in FIG. 9. In this release position, the nipple 12 may be
inserted or removed from the channel 32. As the nipple 12 is
inserted or removed from the channel 32, the retaining lugs 20 are
forced radially outward and out of the channel 32. Returning the
collar 40 to its locking position forces the retaining lugs 20
radially inwardly to engage the retaining groove 18 when the nipple
12 is positioned within the channel 32 as shown in FIG. 6 or to
simply extend into the channel if the nipple 12 is not positioned
within the channel 32 as in FIG. 4.
[0033] When the nipple 12 is received within the channel 32 and the
collar 40 is in its locking position, the tips 22 of the retaining
lugs 20 are received within the retaining groove 18 formed around
the outer surface of the nipple 12. As depicted in FIG. 5, the
retaining groove 18 has inner and outer bearing surfaces 18A and
18B that correspond to the congruent bearing surfaces 22A and 22B
of the tip 22 of the retaining lugs 20. The chamfers that form the
respective bearing surfaces 22A, 22B of the tip 22 of the retaining
lugs 20 and the bearing surfaces 18A, 18B of the retaining groove
18 are cut at an identical angle .theta., illustrated in FIGS. 5
and 8, such that the respective bearing surfaces of the retaining
lugs 20 and retaining groove 18 will flushly contact one another
across a substantial surface area as opposed to along a line or at
a single point.
[0034] The bearing surfaces 22A and 22B and 18A and 18B of the
retaining lugs 20 and retaining groove 18, respectively have any
useful, congruent profile formed therein. However, the respective
bearing surfaces 22A and 22B of the retaining lugs 20 are
preferably frusto-conical surfaces defined by the chamfer angle
.theta. and the radius of the coupling 10. Mating surfaces 18A and
18B are preferably also frusto-conical surfaces defined by the same
chamfer angle .theta. and the radius of the coupling 10. The cone
defining the frusto-conical surface of the bearing surfaces of the
retaining lugs 20 and the retaining groove 18 is preferably a right
circular cone. The bearing surfaces 22A, 22B comprise only a
section of a frustum of the right circular cone which defines the
preferred form of the respective bearing surfaces of both the
retaining lug and groove. Furthermore, bearing surfaces 22A and 22B
and mating surfaces 18A and 18B are congruent, thereby ensuring
that there will be substantially full facial contact between the
bearing surfaces 22A and 22B and the mating surfaces 18A and 18B,
at the locations where the retaining lugs 20 are extended into the
retaining groove 18. What is more, the surface of the tip 22 is
preferably cylindrical and congruent with the preferably
cylindrical surface of the bottom 18C of the retaining groove 18.
This congruence permits the retaining lugs 20 to be fully inserted
into the retaining groove 18 and facilitates the full facial
contact between the bearing surfaces 22A and 22B of the retaining
lugs 20, and the mating surfaces 18A and 18B of the retaining
groove 18. In the present, preferred embodiment the angle .theta.
is 20 degrees. However, in no case should the angle .theta. exceed
30 degrees. It is possible that the angle .theta. could even be
zero degrees, however, an exceedingly small angle .theta. on mating
surfaces 18A, 18B and 22A, 22B makes it difficult for the retaining
lugs 20 to consistently engage the retaining groove 18 in a
reliable manner. But, by maintaining a relatively small angle
.theta., there is the added benefit that the pressures exerted by
the compressed hydraulic fluids flowing through the coupling 10 are
in large part borne in shear over a substantial surface area by the
retaining lugs 20. As the amount of force transmitted by the
retaining lugs 20 to the collar 40 is a function of the angle of
contact .theta. between the respective bearing surfaces 18A, 18B
and 22A, 22B, maintaining a small angle .theta. on the bearing
surfaces 18A, 18B and 22A, 22B reduces the proportion of the
magnitude of the forces applied longitudinally across the retaining
lugs 20 that is transmitted radially to the collar 40. Therefore,
the angle .theta. is preferably as small as possible. The incidence
of failure of the coupling 10 due to the deformation of the collar
40 is, therefore, correspondingly lower. Furthermore, the increased
area of contact between the respective mating surfaces 18A, 18B and
22A, 22B reduces the stresses applied directly to those mating
surfaces, thereby minimizing the potential for failure of the
coupling 10 due to deformation of those mating surfaces.
[0035] The base 24 of retaining lugs 20 is preferably a cylindrical
surface and will be congruent with the inner surface of the collar
40. The congruent base 24 and inner surface of the collar 40
flushly contact one another across substantially the entire surface
of the base 24 of the retaining lug. In this manner, any radial
force applied to the collar 40 by the retaining lugs 20 is applied
over a surface area that is substantially larger than the point or
line contact areas typically seen in couplings of the prior
art.
[0036] In the preferred embodiment of the present invention, and
for a coupling arranged to connect 3/4" diameter fluid lines, the
area of contact between the bearing surfaces 22A, 22B and the
bearing surfaces 18A, 18B is approximately 0.14 square inches for
each bearing surface of each retaining lug 20. This area of contact
between the bearing surfaces of the retaining lugs 20 and the
bearing surfaces of the retaining groove 18 may vary with the
application or size of the coupling 10, but should not be lower
than 0.1 square inches for the bearing surfaces of retaining lugs
20 intended for use with 3/4 in. diameter fluid flow lines.
Likewise, the increased area in shear represented by the
cross-sectional area of the retaining lugs 20 reduces the
likelihood of failure of the coupling 10 due to breakage or
deformation of the retaining lugs 20 themselves.
[0037] While the preferred embodiment of the present invention has
been described, it should be understood that various changes,
adaptations and modifications may be made therein without departing
from the spirit of the invention and the scope of the appended
claims.
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