U.S. patent application number 14/692865 was filed with the patent office on 2016-01-21 for fitting nut with adapted engaging surfaces.
The applicant listed for this patent is Swagelok Company. Invention is credited to Dale C. Arstein, Carl E. Meece, Edward A. Pezak, Peter C. Williams.
Application Number | 20160018030 14/692865 |
Document ID | / |
Family ID | 38222412 |
Filed Date | 2016-01-21 |
United States Patent
Application |
20160018030 |
Kind Code |
A1 |
Arstein; Dale C. ; et
al. |
January 21, 2016 |
FITTING NUT WITH ADAPTED ENGAGING SURFACES
Abstract
A fitting assembly is provided with a first fitting component
having a stepped wall surface; and a second fitting component
radially spaced from the first fitting component when the fitting
assembly is in a finger tight condition prior to pull-up. When the
second fitting component is displaced into contact with the stepped
wall surface during fitting pull-up, the stepped wall surface
assists in separating the first fitting component from the second
fitting component upon fitting disassembly.
Inventors: |
Arstein; Dale C.; (Highland
Heights, OH) ; Meece; Carl E.; (O'Brien, FL) ;
Williams; Peter C.; (Cleveland Heights, OH) ; Pezak;
Edward A.; (Solon, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Swagelok Company |
Solon |
OH |
US |
|
|
Family ID: |
38222412 |
Appl. No.: |
14/692865 |
Filed: |
April 22, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13658147 |
Oct 23, 2012 |
9033372 |
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14692865 |
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13217551 |
Aug 25, 2011 |
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13658147 |
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11639529 |
Dec 15, 2006 |
8007013 |
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13217551 |
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60758688 |
Jan 13, 2006 |
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60834548 |
Jul 31, 2006 |
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Current U.S.
Class: |
285/389 |
Current CPC
Class: |
F16L 15/08 20130101;
F16L 19/103 20130101; F16L 19/08 20130101; F16L 15/00 20130101;
F16L 19/061 20130101; F16L 19/10 20130101 |
International
Class: |
F16L 15/08 20060101
F16L015/08; F16L 19/10 20060101 F16L019/10 |
Claims
1-28. (canceled)
29. A fitting body having a longitudinal axis comprising: a conduit
end socket comprising a shoulder at an axially inner end of said
conduit end socket and an end surface at an axially outer end of
said conduit end socket, said conduit end socket being
characterized by: an inner wall surface that extends axially
between said shoulder and said end surface, said shoulder extends
on a radial line with respect to the longitudinal axis, said inner
wall surface comprises a conduit end capture surface, a ferrule
camming surface, and a tapered wall surface that extends from said
conduit end capture surface to said ferrule camming surface, said
tapered wall surface being tapered in a radially outward direction
towards said axially outer end, said tapered wall surface being
adjacent to said conduit end capture surface.
30. The fitting body of claim 29 wherein said conduit capture
surface tapers at a first angle and said ferrule camming surface
tapers at a second angle both relative to the longitudinal axis,
said first angle and said second angle being different from each
other.
31. The fitting body of claim 30 wherein said conduit end capture
surface tapers at an approximate angle of four degrees and said
ferrule camming surface tapers at an approximate angle of twenty
degrees.
32. The fitting body of claim 29 wherein said conduit end capture
surface and said ferrule camming surface and said tapered wall
surface are frusto-conical.
33. The fitting body of claim 29 wherein said conduit end capture
surface tapers at a first angle, said tapered wall surface tapers
at a second angle, and said ferrule camming surface tapers at a
third angle.
34. The fitting body of claim 33 wherein said first angle, said
second angle and said third angle are all different from each
other.
35. The fitting body of claim 33 wherein said first angle is
approximately four degrees, said second angle is in a range of
approximately fifty minutes to approximately one degree and fifty
minutes, and said third angle is approximately twenty degrees.
36. The fitting body of claim 29 wherein said conduit end capture
surface and said ferrule camming surface are tapered in a radially
outward direction towards said axially outer end.
37. The fitting body of claim 29 wherein said tapered wall surface
is discontinuous with said conduit capture surface and said ferrule
camming surface.
38. The fitting body of claim 29 wherein said tapered wall surface
tapers at an angle that is in a range of approximately fifty
minutes to approximately one degree and fifty minutes.
39. The fitting body of claim 29 adapted for combination with a
drive nut, wherein said fitting body is adapted to be joined with
said drive nut.
40. The fitting body of claim 29 adapted for combination with a
front ferrule and a rear ferrule.
41. The fitting body of claim 39 wherein said fitting body
comprises a male threaded body, and said drive nut comprises a
female threaded nut.
42. The fitting body of claim 29 adapted for combination with a
front ferrule and a rear ferrule, and wherein said fitting body,
said drive nut and said front ferrule and rear ferrule all comprise
stainless steel.
43. The fitting body of claim 29 adapted for combination with a
drive nut to form a conduit fitting, and a conduit end that can be
inserted into said conduit end socket, an end portion of said
conduit end being in contact with said conduit capture surface in a
finger tight condition prior to pull-up, wherein during pull up of
said conduit fitting a portion of said conduit end is radially
displaced into contact with said tapered wall surface.
44. The fitting body of claim 43 wherein after a completed pull-up
of said conduit fitting said portion of said conduit end is
radially displaced into contact with said tapered wall surface with
an axial component of an elastic reaction force against said
conduit end for separating said fitting body from said conduit end
upon disassembly.
45. The fitting body of claim 44 wherein said front ferrule
comprises a rounded front end.
46. A fitting assembly, comprising: a fitting body according to
claim 29; and a conduit end having a portion that axially aligns
with and contacts said conduit capture surface when the fitting
assembly is in a finger tight position; wherein when the fitting
assembly is pulled-up a portion of the conduit end contacts said
tapered wall surface.
47. The fitting assembly of claim 46 wherein during pull up said
conduit end contacts said tapered wall surface with an axial
component of elastic reaction force between said conduit end and
said tapered wall surface, such that when the fitting assembly is
loosened, said axial component of elastic reaction force assists in
separating said conduit end from said tapered wall surface.
48. The fitting assembly of claim 47 wherein said body and said
conduit end comprise metal.
49. The fitting assembly of claim 48 wherein said body and said
conduit end comprise stainless steel.
50. The fitting body of claim 39 adapted for combination with a
front ferrule and a rear ferrule.
51. The fitting body of claim 39 adapted for combination with a
front ferrule and a rear ferrule, and wherein said fitting body,
said drive nut and said front ferrule and rear ferrule all comprise
stainless steel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation application of
pending U.S. Ser. No. 13/658,147, filed Oct. 23, 2012, entitled
"Fitting Nut with Adapted Engaging Surfaces"; which is a
continuation application of and claims priority to U.S. patent
application Ser. No. 13/217,551, filed Aug. 25, 2011, entitled
"Fitting for Tube and Pipe", abandoned; which is a continuation
application of and claims priority to U.S. patent application Ser.
No. 11/639,529, filed Dec. 15, 2006, entitled "Fitting for Tube or
Pipe", now U.S. Pat. No. 8,007,013; which claims priority from U.S.
provisional application Ser. No. 60/758,688, entitled "FITTING FOR
TUBE OR PIPE," filed on Jan. 13, 2006, expired; and from U.S.
provisional application Ser. No. 60/834,548, entitled "FITTING FOR
TUBE OR PIPE," filed on Jul. 31, 2006, expired; the entire
disclosures of which are all fully incorporated herein by reference
in their entireties.
BACKGROUND OF THE INVENTION
[0002] Fittings may be used to join or connect the end of a tube or
other conduit to another member, whether that other member be
another tube or conduit end such as through T-fittings and elbow
fittings, for example, or a device that needs to be in fluid
communication with the tube end, such as for example, a valve. One
type of fitting uses a gripping arrangement including two ferrules
that provide a gripping and sealing action between a tube and a
body under the influence of a female threaded drive nut. Other
types of fittings are also known, such as, for example, single
ferrule fittings, fittings that use other types of tube gripping
devices, and fittings that use male threaded drive nuts.
[0003] Tube fitting components that are radially displaced or
expanded upon pull-up take up a portion of the deformation energy
of pull-up and may contact radially adjacent and/or radially nearby
fitting component surfaces as a result of the expansion or
displacement. For example, the tubing inboard of the tube gripping
member, such as, for example, the front ferrule of a two ferrule
fitting or the ferrule of a single ferrule fitting, may expand
radially outward during fitting pull-up and takes up a portion of
the deformation energy of pull-up.
SUMMARY OF THE INVENTION
[0004] The application pertains generally to a fitting assembly
that is configured to assist in separating two or more fitting
components during disassembly of the fitting if and when the mating
components contact each other during pull-up, for example, due to
radially outward movement of a fitting component as a result of
axial compression of the fitting component during fitting
installation. As used herein, fitting components of a fitting
assembly may include, but are not limited to, bodies, such as, for
example, coupling bodies and valve bodies, drive nuts, tube
gripping members, such as, for example, ferrules, tubing or other
conduits, and fitting installation tools, such as, for example,
tube gripping member installation tools or pre-swaging tools.
[0005] According to one inventive aspect, one or more fitting
component engaging surfaces may be configured to reduce radial
reaction forces between two contacting fitting components of a
pulled-up fitting. For example, a surface of a first fitting
component that is axially aligned with a second fitting component
during fitting assembly may be radially recessed to provide reduced
radial reaction forces between the recessed surface and the second
component during disassembly. As used herein, two components are
"axially aligned" if a portion of the first component is located at
the same axial position (e.g., a position along a fitting) as a
portion of the second fitting component. As another example of
fitting components configured to reduce radial reaction forces
resulting from contact between fitting components of a pulled-up
fitting, a surface of a first fitting component that contacts a
second fitting component during fitting assembly may be axially
shortened to reduce a length of contact between the first and
second components and, as a result, to provide reduced radial
reaction forces between the first and the second components during
disassembly.
[0006] Accordingly, in one exemplary embodiment, a fitting
component includes a body having a tube socket that includes a
recessed wall surface radially spaced from a tapered tube capture
surface. Such a fitting component may be used in a fitting assembly
that includes a tube having an end portion that engages the tube
capture surface prior to fitting pull-up. When the fitting assembly
is pulled-up, additional engagement between the tube socket and the
tube end portion, for example, due to radially outward deflection
or bowing of the tube end resulting from axial compression of the
tube end, produces axial and radial reaction force components
between the tube socket and tube end portion. By providing a
recessed longitudinal surface in the tube socket, the radial force
component between the first and second components may be reduced,
thereby assisting in separation of the first and second components
during disassembly of the fitting assembly.
[0007] According to another inventive aspect, one or more fitting
component mating surfaces may additionally or alternatively be
configured to produce an axial component of reaction force between
two contacting fitting components of a pulled-up fitting. This
axial component of elastic reaction force may assist in separating
the two fitting components during disassembly of the pulled-up
fitting. For example, a first fitting component may include a
stepped wall surface, which may, for example, include a tapered
surface, that contacts a second fitting component during fitting
pull-up to produce an axial component of reaction force, which may
assist in separation of the first and second fitting components
when the fitting is disassembled.
[0008] Accordingly, in one exemplary embodiment, a fitting assembly
has a first fitting component having a stepped wall surface and a
second fitting component radially spaced from the tapered
longitudinal surface when the fitting assembly is in a finger tight
condition prior to pull-up. When the second fitting component is
radially displaced into contact with the stepped wall surface
during fitting pull-up, the stepped wall surface assists in
separating the first fitting component from the second fitting
component upon fitting disassembly. For example, engagement of the
second fitting component with the stepped wall surface may produce
an axial component of reaction force that assists in axially moving
the second fitting component away from the first fitting component.
As another example, the stepped wall surface may provide for a
reduced radial reaction force between the first and second fitting
components upon initial axial movement of the second fitting
component during fitting disassembly.
[0009] In one such embodiment, a fitting body is provided with a
tube socket having a stepped wall surface, such that when a tube
that is assembled with the fitting body radially expands to contact
the stepped wall surface, an axial component of reaction force
resulting from this contact may assist in separating the tube from
the fitting body upon disassembly of the fitting. Additionally, the
stepped condition of the tube socket wall may reduce the radial
force between the fitting body and the tube during withdrawal of
the tube from the fitting.
[0010] In an exemplary embodiment, a component of a tube fitting
for a tube end includes a body having a tube end socket centered on
an axis, for receiving a tube end. The tube end socket has a
shoulder defining an axially inner end of the socket, a tapered
tube capture surface adjacent the shoulder for engaging the tube
end, a camming mouth near an axially outer end of the tube end
socket, for engaging a ferrule, and a stepped wall surface disposed
between the tube capture surface and the camming mouth. When the
tube expands to contact the stepped wall surface during fitting
pull-up, this contact between the stepped wall surface and the tube
produces an axial component of elastic reaction force against the
tube, which can assist in tube removal from the socket upon fitting
disassembly. Additionally, the stepped condition of wall surface
may reduce the radial force between the tube socket and the tube
end, for example, by providing radial separation between the tube
and at least a portion of the tapered surface during withdrawal of
the tube from the tube socket.
[0011] In another embodiment, a fitting body may be provided with a
tapered tube capture surface that is extended to assist in
separation of the tube from the fitting body upon disassembly of
the fitting. For example, a tapered tube capture surface in a tube
socket of a fitting body may extend to a camming mouth of the tube
socket, thereby eliminating any intermediary or transitional wall
surface between the tube capture surface and the camming mouth. In
one such exemplary embodiment, a tube fitting for a tube end
includes a fitting body having a tube end socket centered on an
axis, for receiving a tube end. The tube socket includes a shoulder
defining an axially inner end of the socket, a tapered tube capture
surface outward of the shoulder for engaging the tube end, and a
camming mouth outward of and directly adjacent to the tube capture
surface, for receiving at least a portion of a ferrule.
[0012] In another embodiment, a drive nut is provided with an inner
wall having a tapered longitudinal surface, such that when a tube
gripping member that is assembled with the drive nut and a fitting
body is displaced into contact with the tapered longitudinal
surface, an axial component of elastic reaction force resulting
from this contact may assist in separating the tube gripping member
from the drive nut upon disassembly of the fitting. Additionally,
the tapered condition of the longitudinal wall may reduce the
radial force between the drive nut and the tube gripping member
during separation of the tube gripping member from the drive nut,
for example, by providing radial separation between the tube
gripping member and at least a portion of the tapered surface
during fitting disassembly.
[0013] In other embodiments, multiple fitting components may be
configured to reduce radial reaction forces and/or increase axial
reaction forces between contacting fitting component surfaces of a
pulled-up fitting, thereby assisting in disassembly of the fitting.
For example, a fitting assembly may include a fitting body with a
tube socket having a tapered wall to assist in separating a tube
end from the fitting body during fitting disassembly, and a drive
nut with an inner wall having a tapered longitudinal surface to
assist in separating a tube gripping member from the drive nut
during fitting disassembly.
[0014] According to still another inventive aspect of the present
application, a fitting component including a tube socket configured
to receive a tube end may be provided with a counter-bowing feature
that reduces radially outward expansion or deflection of the tube
end, including, for example, bowing or barreling of a tube end
resulting from axial compression of the tube end. The reduced
bowing of the tube end may result in reduced radial reaction forces
between the tube end and the socket, which may assist in separation
of the first fitting component and the tube end during
disassembly.
[0015] In one such embodiment, a fitting component includes a
socket for receiving a tube end, the socket being defined by an
axial longitudinal wall surface and a shoulder including a surface
extending axially and radially inward from an axially inner end of
the axial longitudinal wall surface. When a tube end is inserted in
the socket and axially compressed against the shoulder, the
shoulder surface is configured to apply counter bowing forces to
the tube end to reduce bowing of the tube end during axial
compression.
[0016] Further advantages and benefits will become apparent to
those skilled in the art after considering the following
description and appended claims in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a partial sectional view of a tube fitting having
a tube socket with a recessed intermediate wall surface, shown in a
finger tight condition before pull-up of the fitting;
[0018] FIG. 1A is an enlarged sectional view of a portion of the
tube socket of FIG. 1;
[0019] FIG. 1B is an enlarged sectional view of a portion of an
alternative tube socket for the tube fitting of FIG. 1, also shown
in a finger tight condition before pull up of the fitting;
[0020] FIG. 2 is a partial sectional view of the tube fitting of
FIG. 1 in a pulled-up condition;
[0021] FIG. 2A is an enlarged sectional view of a portion of the
tube socket of FIG. 2;
[0022] FIG. 2B is an enlarged sectional view of a portion of the
tube socket of FIG. 1B, shown in a pulled-up condition;
[0023] FIG. 3 is a partial sectional view of a tube fitting having
a tube socket with a tapered intermediate wall surface, shown in a
finger tight condition before pull-up of the fitting;
[0024] FIG. 3A is an enlarged sectional view of a portion of the
tube socket of FIG. 3;
[0025] FIG. 4 is a partial sectional view of the tube fitting of
FIG. 3 in a pulled-up condition;
[0026] FIG. 5 is a partial sectional view of a tube fitting having
a tube socket with no intermediate wall surface, shown in a finger
tight condition before pull-up of the fitting;
[0027] FIG. 5A is an enlarged sectional view of a portion of the
tube socket of FIG. 5;
[0028] FIG. 6 is a partial sectional view of the tube fitting of
FIG. 5 in a pulled-up condition;
[0029] FIG. 6A is an enlarged sectional view of a portion of the
tube socket of FIG. 6;
[0030] FIG. 7 is a partial sectional view of a tube fitting having
a drive nut with a tapered inner wall surface, shown in a finger
tight condition before pull-up of the fitting;
[0031] FIG. 7A is an enlarged sectional view of a portion of the
drive nut and ferrules of the fitting of FIG. 7;
[0032] FIG. 8 is a partial sectional view of the tube fitting of
FIG. 7 in a pulled-up condition;
[0033] FIG. 9 is a partial sectional view of a single ferrule type
tube fitting having a drive nut with a tapered inner wall surface,
shown in a finger tight condition before pull-up of the
fitting;
[0034] FIG. 10 is an enlarged partial sectional view of the tube
fitting of FIG. 9 in a pulled-up condition;
[0035] FIG. 11 is a partial sectional view of a tube fitting with a
female threaded body and a male threaded drive nut with a tapered
inner wall surface, shown in a finger tight condition before
pull-up of the fitting;
[0036] FIG. 12 is an enlarged partial sectional view of the tube
fitting of FIG. 11 in a pulled-up condition;
[0037] FIG. 13 is a partial sectional schematic view of a fitting
component having a tube socket with an axially tapered shoulder
surface, with a tube end installed in the tube socket in an axially
compressed condition;
[0038] FIG. 14 is a partial sectional view of a fitting
installation tool for tightening a tube gripping member to a tube
end, the tool including a tube socket with an axially tapered
shoulder surface;
[0039] FIG. 15 is a partial sectional view of a tube fitting having
a tube socket with an axially tapered shoulder surface, shown in a
finger tight condition before pull-up of the fitting; and
[0040] FIG. 16 is an enlarged partial sectional view of the tube
fitting of FIG. 15 in a pulled-up condition.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION
[0041] This disclosure relates to fitting components, for use with
any type of fluid conduit, including tube or pipe. The exemplary
embodiments are described herein with the terms "tube" and
"tubing," but may be used with pipe and other conduits. The
disclosure is applicable to fitting components of varying
constructions, materials, sizes, and dimensions such as diameters,
for example, all of which are described herein with the term "tube
fitting." The tightening or preparation of a fitting connection is
referred to herein as fitting "pull-up" or "make up," with both
terms being used interchangeably. Fitting pull-up or make up is not
limited to a specific pull-up position.
[0042] Tube fitting components that are radially displaced or
expanded upon fitting pull-up may contact radially adjacent and/or
radially spaced fitting component surfaces as a result of the
expansion or displacement. Examples of this radially outward
movement include bowing or barreling of a tube end resulting from
axial compression of the tube end, or outward deflection of a tube
gripping member, such as a ferrule or ferrules, during fitting
pull-up. The present application contemplates providing a fitting
that may be configured to assist in the separation of these
contacting fitting components during disassembly of the fitting,
for example, by reducing radial reaction forces (which tend to
resist separation) between the components, or by increasing axial
reaction forces (which tend to promote separation) between the
components. According to one inventive aspect, this assistance in
separating the components may be accomplished by providing a first
fitting component with a recessed surface radially spaced from a
surface that engages a displaced portion of a second component upon
fitting pull-up. As the second component is separated from the
first component during fitting disassembly, the displaced portion
is axially aligned with the recessed surface, causing radial
reaction forces between the first and second fitting components to
be reduced, thus facilitating further separation of the first and
second fitting components.
[0043] According to another inventive aspect, assistance in
separating contacting first and second fitting components may be
accomplished by providing the first fitting component with a
tapered longitudinal surface for engagement with a displaced
portion of the second fitting component. For example, a tube end
socket may include a tapered longitudinal wall to assist in removal
of a tube end. As another example, a drive nut may include a
tapered longitudinal surface on an inner wall to assist in
separation of the drive nut from a tube gripping device, such as,
for example, a ferrule or ferrules. In yet another exemplary
embodiment, both the tube end socket and the drive nut may include
tapered longitudinal surfaces to assist in separation from the tube
end and tube gripping device, respectively.
[0044] An exemplary type of fitting with which the invention can be
used includes two ferrules that provide a gripping and sealing
action between a tube and a body under the influence of a female
threaded drive nut. While exemplary embodiments illustrated and
described herein show various inventive aspects as used with this
two ferrule type fitting, these inventive aspects are also
applicable to other types of fittings, such as, for example, single
ferrule fittings, fittings that use other types of tube gripping
devices, and fittings that use male threaded drive nuts. Also,
while exemplary embodiments include fittings for use with stainless
steel tubing having diameters of 1/4 inch, 3/8 inch and 1/2 inch,
the inventive aspects of the present application may be provided
with fittings for use with many sizes and types of tubing.
[0045] FIGS. 1 and 2 illustrate a tube fitting 10 that is an
exemplary embodiment of some of the inventive aspects described
herein. The tube fitting 10 is used for connection with a tube 12
and includes a fitting body 14. The fitting body 14 is merely
representative of the various different types of assemblies and
fittings with which the invention is usable. For example, the
fitting body can be a standalone device, or a portion of a valve,
or a union, or any other type of fluid control device or fluid flow
device.
[0046] The particular fitting body 14 that is illustrated has a
main body portion 16 and a projecting socket wall 20. The socket
wall 20 forms the radially outer periphery of a tube end socket 22
in the fitting body 14.
[0047] The fitting body 14 has a radially extending shoulder 24
that defines or is located at an axially inner end 26 of the socket
22. The socket wall 20 has an outer terminal end surface 28
extending generally radially with respect to an axis 30 of the
fitting body 14. The terminal end surface 28 defines or is located
at an axially outer end 32 of the socket 22.
[0048] A male thread 40 is formed on the exterior of the socket
wall 20. The male thread 40 cooperates with a female thread 42 on a
drive nut 44. The drive nut 44 is rotatable and movable axially
relative to the fitting body 14.
[0049] The socket wall 20 has an inner wall surface 50 that
partially defines the tube end socket 22. The inner wall surface 50
extends between the axially inner end 26 of the socket 22 and the
axially outer end 32 of the socket. In the illustrated embodiment,
the inner wall surface 50 extends between the shoulder 24 and the
terminal end surface 28. The inner wall surface 50 may have various
configurations in accordance with the inventive aspects described
herein. Several embodiments are illustrated herein, and others will
be readily apparent to those skilled in the art.
[0050] In the embodiment illustrated in FIGS. 1 and 2, the inner
wall surface 50 of the tube end socket 22 includes a tube capture
surface 52, a camming mouth portion 54, and a intermediate wall
surface portion 60 (the details of which may be exaggerated in the
drawings for clarity) between the tube capture surface 52 and the
camming mouth portion 54. The exemplary tube capture surface 52
extends axially outward from the shoulder 24; however, in other
embodiments, the tube capture surface 52 may be axially spaced from
the shoulder 24. While the tube capture portion may take many
different shapes, angles, contours, or geometries, the exemplary
tube capture surface 52 of the inner wall surface 50 is a
frustoconical tapered surface that tapers radially outward as it
extends axially away from the shoulder 24. In the illustrated
embodiment, as shown in FIG. 1A, the tube capture surface 52 has a
taper angle 53. In an exemplary embodiment, the taper angle 53 is
approximately four degrees (4.degree.) relative to the axis 30. The
taper angle 53 of the tube capture surface 52, and its overall
diameter, may be selected to lightly hold or capture the end of the
tube 12 prior to fitting pull-up, to inhibit the tube 12 from
rotating in the socket 22 during pull-up of the fitting 10.
[0051] The exemplary camming mouth 54 is adapted to engage a
ferrule (described below) that forms part of the tube fitting 10,
and to cam the ferrule radially inward, thereby to provide, in a
known manner, a gripping and sealing connection between the tube
12, the ferrule, and the fitting body 14. The angle 57 of the
camming mouth 54, as referenced in FIG. 1, may be selected to
provide the desired gripping and sealing connection. In an
exemplary embodiment, the camming mouth angle 57 is approximately
20.degree. relative to the axis 30.
[0052] The tube 12 that is illustrated is merely representative of
the various different types and sizes of conduits with which the
invention is usable. The particular tube 12 that is illustrated has
a generally cylindrical configuration including parallel,
cylindrical inner and outer side surfaces 70 and 72 centered on the
axis 30. The tube 12 has an inner tube end 74 and an outer portion
shown broken away at 76. When the tube fitting 10 is made up, the
terminal end portion 74 of the tube 12 is located in the socket 22
of the fitting body 14, and the tube extends axially outward
therefrom, and outwardly of the fitting body 14.
[0053] The particular tube fitting 10 that is shown in FIGS. 1 and
2 includes, in addition to the fitting body 13, a front ferrule 80,
a rear ferrule 82, and a drive nut 44. The invention is applicable
also to fittings including other types of tube gripping devices,
including, for example, tube fittings that include only one ferrule
rather than two ferrules. The invention is applicable also to tube
fittings that include front and/or rear ferrules, and drive nuts,
of differing constructions, many of which designs are known in the
art.
[0054] FIG. 1 illustrates the fitting 10 in a finger-tight
condition prior to pull-up. The tube 12 is inserted into the socket
22. The terminal end portion of the tube 74 extends into contact
with the tube capture surface 52 of the inner wall surface 50 of
the fitting body 14.
[0055] The outer surface 72 of the tube 12 is smaller in diameter
than the intermediate wall surface 60 of the fitting body 14, and
is thus spaced radially inward from the intermediate wall surface
60. The ferrules 80 and 82 are on the tube 12, and the drive nut 44
is threadedly engaged with the fitting body 14.
[0056] FIG. 2 illustrates the fitting 10 after pull-up. The drive
nut 44 is screwed farther onto the fitting body 14. The movement of
the drive nut 44 causes the ferrules 80 and 82 to provide a
gripping and sealing engagement between the tube 12 and the fitting
body 14.
[0057] Axially and radially inward movement of the nose of the
front ferrule 80 causes the tube 12 to be pushed axially inward
into engagement with the shoulder 24. Axial force on the tube 12
causes the portion of the tube end 74 that is located axially
inward of the front ferrule 80 to barrel radially outward. This
tube portion 74 might contact the intermediate wall surface portion
60 of the fitting body 14, for example, as shown in FIG. 2,
producing a radial component of reaction force, which may also be
referred to as an interference load or a friction load.
[0058] The intermediate wall surface portion 60 of the exemplary
inner wall surface 50 extends between the tube capture surface 52
and the camming mouth portion 54. The surface 60 is centered on the
axis 30. The exemplary intermediate wall surface 60 includes a
stepped portion 61 (see FIG. 1A) axially outward of the tube
capture surface 52 and a recessed portion 62 axially outward of the
stepped portion 61, such that the recessed portion 62 is radially
spaced from the tube capture surface 52. Thus, the diameter of the
socket 22 is greater at the recessed portion 62 than at any point
along the tube capture surface 52. Further, the average diameter of
the inner wall surface 50 of the socket 22 is increased, as
compared to a fitting tube socket without such a recess. Also,
while the illustrated stepped portion 61 is directly adjacent to
the tube capture surface 52, in other embodiments, the stepped
portion 61 may be axially spaced from the outer edge of the tube
capture surface 52.
[0059] In the illustrated embodiment of FIGS. 1, 1A, 2, and 2A, the
exemplary stepped portion 61 is substantially perpendicular to the
exemplary recessed portion 62, which is substantially cylindrical.
As a result, when the tube end 74 expands during fitting pull-up
and contacts the recessed portion 62, as shown in FIG. 2B, reaction
forces between the cylindrical recessed portion 62 and the tube end
74 are substantially radial (i.e., non-axial). Also, contact
between the expanded tube end 74 and the exemplary stepped portion
61 is minimal, resulting in little or no axial reaction forces from
such contact. During disassembly of the exemplary fitting 10,
engagement between the tapered tube capture surface 52 and the tube
end 74 will provide axial reaction forces to assist in separating
the tube end from the fitting body. During separation, as the end
of the tube 74, which has experienced less expansion or
displacement, axially moves into the recessed portion 62 of the
tube socket, the radial reaction forces between the recessed
portion 62 and the tube 12 are reduced or eliminated, thus
assisting in separating the tube end 74 from the fitting body 14.
Further, by increasing the average diameter of the inner wall
surface 50 of the tube socket 22, total radial reaction forces
along a length of contact between the tube 12 and the tube socket
22 are reduced.
[0060] In another embodiment, as shown in the partial views of
FIGS. 1B and 2B, the stepped portion 61' may be tapered, allowing
for the potential for increased contact between the tube and the
stepped portion 61' upon fitting pull-up, as shown in FIG. 2B. The
potential contact between the tube 12 and the tapered stepped
portion 61' provides an axial component of reaction force between
the tube and the stepped portion 61' during fitting disassembly,
which may assist in separation of the tube 12 from the fitting body
14. While the stepped portion 61' may be provided at many different
angles and with many different surface contours, an exemplary
embodiment includes a frustoconical stepped portion 61' at a taper
angle 63' of approximately 20.degree. relative to the axis 30.
[0061] In other embodiments, the stepped portion 61' may be
steeper, with a larger taper angle 63', resulting in an axially
shorter stepped portion 61' and a longer recessed portion 62', or
the stepped portion 61' may be shallower, with a smaller taper
angle 63', resulting in an axially longer stepped portion 61' and a
shorter recessed portion 62'. Finite element analysis and testing
of a particular fitting can determine how much taper is needed, in
order to achieve a system that can provide an axial elastic
reaction force on the tube, to assist in tube removal, upon
disassembly.
[0062] In various exemplary embodiments, a stepped or tapered
intermediate wall portion of a fitting body tube socket may be
discontinuous with tube capture and camming mouth portions of the
tube socket; that is, the stepped or tapered intermediate wall may
be provided at a different angle than the tube capture and camming
mouth portions 152, 154, may be radially spaced from the tube
capture and camming mouth portions 152, 154, and/or may be axially
spaced from the tube capture and camming mouth portions 152,
154.
[0063] In one embodiment, as shown in FIGS. 3 and 4, a fitting body
100 may be provided with a tube socket including a stepped portion
160 having a tapered longitudinal surface that extends to an inner
edge of a camming mouth portion 154, thereby excluding a separate
recessed portion of the tube socket 122. Engagement or contact
between the stepped portion or tapered inner wall 160 and the
expanded tube end 174 after fitting pull-up, when such contact
occurs, produces an axial component of reaction force along the
length of contact between the tube 112 and the tapered wall 160,
thus assisting in separating the tube end from the fitting body
114. Also, while the illustrated stepped or tapered wall portion
160 is directly adjacent to the tube capture portion 152, the
stepped portion may also be axially spaced from the outer edge of
the tube capture portion 152.
[0064] The tapered condition of the wall surface 160 (as opposed to
a cylindrical surface) can assist in removal of the tube 112 from
the socket 122 upon disassembly. Once the tube end 174 is initially
broken free from the tapered wall surface 160, the tube 112 can be
removed without any substantial force, due to the reduction or
elimination of radial reaction forces between the tube end 174 and
the wall surface 160.
[0065] The tapered wall surface may be provided at a variety of
taper angles and with a variety of surface contours. In one
embodiment, a tapered wall surface is frustoconical and tapered to
connect an outer edge of a tube capture portion with an inner edge
of the camming mouth. In the illustrated embodiment of FIGS. 3 and
4, the tapered wall surface 160 is frustoconical with a taper angle
163. In one exemplary embodiment, the taper angle 163 is
approximately 50 minutes, or five-sixths of a degree, relative to
the axis 130. In such an embodiment, the taper angle 163 of the
exemplary tapered wall surface 160 is significantly less than the
taper angle 153 of the tube capture portion 152. As described
below, the taper angle 163 of the tapered wall surface 160 is
selected to assist in removal of a tube end if the tube end is
expanded radially outward into contact with the socket wall during
fitting pull-up. One desirable range of taper angles is from 50
minutes to one degree and fifty minutes, with a tolerance of plus
or minus 15 minutes.
[0066] According to another inventive aspect of the present
application, separation of a tube end from a fitting body may
additionally or alternatively be facilitated by reducing the length
of the portion of tube contacting the tube socket upon fitting
pull-up. This may reduce the total radial reaction forces between
these contacting surfaces, thereby assisting the separation of the
tube end from the fitting body upon disassembly. In one embodiment,
the length of contact between the expanded tube end and the tube
end socket may be reduced by providing a recessed or tapered
longitudinal surface in the tube end socket, as described with
regard to the embodiments of FIGS. 1-4 above. In another
embodiment, the length of contact between the expanded tube end and
the tube end socket may additionally or alternatively be reduced by
reducing the length of the tube socket. FIGS. 5 and 6 illustrate a
fitting 200 that is one such exemplary embodiment. In the fitting
200, the fitting body 214 has a shallow or shortened socket 222.
The outer periphery of the socket 222 is defined by an inner wall
surface 250 of the fitting body 214. The inner wall surface 250
includes a tube capture portion 252 and a camming mouth 254, the
angles of which may be exaggerated in the drawings for clarity.
[0067] The exemplary inner wall surface 250 of FIGS. 5 and 6 does
not include an intermediate wall surface like the intermediate wall
surfaces 60, 160 of the embodiments of FIGS. 1-4. Rather, the tube
capture portion 252 abuts the camming mouth 254. That is, the
camming mouth 254 is directly adjacent the tube capture surface 252
so as to provide a zero intermediate or transition length tube
socket 222. Thus, there is neither a tapered wall surface, a
stepped wall surface, nor a cylindrical wall surface between the
tube capture portion 252 and the camming mouth 254 of the exemplary
fitting body 214. While the taper angles 253, 257 of the tube
capture portion 252 and camming mouth 254 may be any number of
different angles, as determined through testing and finite element
analysis, in an exemplary embodiment, the tube capture portion 252
has a taper angle 253 of approximately 4.degree., and the camming
mouth has a taper angle of approximately 20.degree..
[0068] In other embodiments, the tube socket length may be selected
to provide desired radial forces between the tube socket and the
tube end, both upon fitting pull-up and after disassembly of the
fitting. The shallow tube socket may alternatively be provided with
a cylindrical intermediate tube wall or a stepped intermediate tube
wall between a tube capture surface and a camming mouth. An
appropriate socket length and/or intermediate tube wall geometry
could be determined by finite element analysis and testing.
[0069] In accordance with other inventive aspects, one or more
tapered longitudinal surfaces may be provided on one or more other
fitting assembly components. In one embodiment, a tapered
longitudinal surface may be provided on an inner wall of a drive
nut of a fitting assembly to engage a portion of a tube gripping
device assembled with the fitting when a portion of the tube
gripping device is displaced outward and into contact with the
inner wall of the nut during pull-up. This contact between the
tapered longitudinal surface and the tube gripping device produces
an axial component of an elastic reaction force against the tube
gripping device, which can assist in separation of the nut from the
tube gripping device upon fitting disassembly. FIGS. 7-12
illustrate exemplary embodiments of fittings including drive nuts
having one or more of such tapered longitudinal surfaces.
[0070] According to one embodiment, FIGS. 7 and 8 illustrate a
two-ferrule tube fitting 300. The tube fitting 300 may be used for
connection with a tube 312 and includes a fitting body 314. The
fitting body 314 is merely representative of the various different
types of assemblies and fittings with which the invention is
usable. For example, the fitting body can be a standalone device,
or a portion of a valve, or a union, or any other type of fluid
control device or fluid flow device. Further, the fitting body 314
may, but need not, be provided with recessed or tapered
longitudinal surfaces, such as, for example, the tapered tube
capture and tube end socket wall surfaces described above and
illustrated in FIGS. 1-6. The particular tube fitting 300 that is
shown in FIGS. 7-8 includes, in addition to the fitting body 314, a
front ferrule 380, a rear ferrule 382, and a drive nut 344.
[0071] FIGS. 7 and 7A illustrate the fitting 300 in a finger tight
condition prior to pull-up. The tube 312 is inserted through the
nut 344 and into the socket 322. The front ferrule 180 is disposed
in a first portion of a recess 345 in the nut 344, and the rear
ferrule 382 is disposed in a second portion of the recess 345.
Included in the recess is a frustoconical drive surface 349 for
driving the ferrules 380, 382 into engagement with the tubing 312
during pull-up.
[0072] FIG. 8 illustrates the fitting 300 after pull-up. The drive
nut 344 is screwed further onto the fitting body 314. The movement
of the drive nut 344 causes the ferrules 380 and 382 to provide a
gripping and sealing engagement between the tube 312 and the
fitting body 314.
[0073] Axially and radially inward movement of a nose of the front
ferrule 380 may cause an outer portion 380r of the front ferrule
380 to expand or deflect outward. Likewise, axially and radially
inward movement of an inner, gripping portion of the rear ferrule
382 may cause an outer portion 382r of the rear ferrule 382 to
expand or deflect outward. Under some circumstances, one or both of
these outer portions of the ferrules 380, 382 may contact an inner
wall 346 of the drive nut 344 during pull-up. In the exemplary
embodiment of FIGS. 7 and 8, tapered longitudinal surfaces 347, 348
are provided on the inner wall 346 at locations axially aligned
with the front and rear ferrules 380, 382. It should be noted that
in other exemplary embodiments, tapered longitudinal surfaces may
be provided axially aligned with only one of the two ferrules, or
one continuous tapered longitudinal surface on the inner wall may
extend to be axially aligned with both ferrules (not shown). In the
illustrated embodiment of FIGS. 7 and 8, when the outer portions
380r, 382r of the front and rear ferrules 380, 382 deflect during
pull-up, as shown in FIG. 8, one or both of the outer portions
380r, 382r may contact a corresponding one or both of the tapered
longitudinal surfaces 347, 348, resulting in both a radial and an
axial component of reaction force.
[0074] The tapered condition of these inner wall surfaces 347, 348
can assist in separation of the nut 344 from one or both ferrules
380, 382 upon disassembly. The axial component of reaction force
produced by contact between the tapered surfaces 347, 348 and the
ferrule or ferrules 380, 382 can assist in separation of the nut
344 from either or both of the ferrules 380, 382. Once the ferrule
or ferrules 380, 382 are initially broken free from the tapered
wall surfaces 347, 348, the nut 344 may be separated without any
substantial force, due to the resulting radial separation or
reduction in radial reaction force between the ferrule or ferrules
380, 382 and the tapered wall surfaces 347, 348.
[0075] To provide both sufficient radial containment of the
ferrules and a sufficient axial reaction force between contacting
nut and ferrule surfaces during disassembly, the taper angles 341,
343 of the inner wall surfaces 347, 348 of the drive nut 344, as
measured from the axis 330 of the drive nut, may, for example, each
range from greater than 0.degree. up to approximately 45.degree..
These two angles 341, 343 may, but need not, be the same. In an
exemplary embodiment, the taper angles 341, 343 may each range from
about 5.degree. up to about 30.degree., and in a more preferred,
but not required embodiment, the tapered angles 341, 343 may each
range from about 10.degree. to about 20.degree.. In the illustrated
embodiment of FIGS. 7 and 8, the tapered wall surfaces 347, 348
each have a taper angle 341, 343 of about 10.degree. relative to
the axis 330.
[0076] As described above, the taper angle of the tapered wall
surface in a drive nut may be selected to assist in separation of
the drive nut from the tube gripping device, such as, for example,
a ferrule or ferrules, if any portion of the tube gripping device
is expanded or deflected radially outward into engagement with the
inner wall of the drive nut during pull-up. Additionally, a gap
between the outer portion or portions of the tube gripping device
and the tapered longitudinal surface or surfaces of the drive nut
in the fitting's pre-tightened, finger tight condition may be
selected independently or in combination with the taper angle to
provide a desired radial reaction load between the outer portions
of the ferrule or ferrules and the inner wall of the drive nut, to
assist in tightening the tube gripping device to the tube end. In
an exemplary embodiment, as shown in FIGS. 7 and 7A, a gap g1 is
provided between the front ferrule outer portion 380r and the
tapered longitudinal surface 347, and a gap g2 is provided between
the rear ferrule outer portion 382r and the tapered longitudinal
surface 348. The dimensions of these gaps and the taper angles of
the tapered longitudinal surfaces may be varied to produce desired
radial reaction forces during fitting pull-up, such as, for
example, to produce radial reaction forces consistent with those
experienced during pull-up of the fitting 300 with a nut having
cylindrical inner wall surfaces, such as the drive nuts 44, 144,
244 shown in FIGS. 1-6. As such, a drive nut 344 with tapered
longitudinal surfaces may be interchangeable with a nut having
cylindrical inner wall surfaces, thereby allowing use of the same
fitting body and tube gripping device. In one such exemplary
embodiment, a tube fitting 300 for 1/2 inch tubing includes a gap
g1 of approximately 0.010 inches between the front ferrule 380 and
the tapered longitudinal surface 347, and a gap g2 of approximately
0.009 inches between the rear ferrule 382 and the tapered
longitudinal surface 348.
[0077] According to another inventive aspect, tapered longitudinal
surfaces may be provided on multiple components of a fitting to
assist in the separation of multiple sets of contacting fitting
components during fitting assembly. In one embodiment, tapered
longitudinal surfaces are provided both on an inner wall of a body
tube socket and on an inner wall of a drive nut, for separation
from the tube end and tube gripping device, respectively, during
fitting disassembly. In the illustrated exemplary embodiment of
FIGS. 7 and 8, in addition to the tapered longitudinal surfaces
347, 348 on the nut 344, as described above, a tapered intermediate
socket wall surface 360 is provided between a tube capture portion
352 and a camming mouth 354, consistent with the tapered wall
surface 160 of FIGS. 3 and 4, for assisting in separation of the
fitting body 314 from the tube 312 during disassembly of the
pulled-up fitting 300.
[0078] FIGS. 9 and 10 illustrate a fitting 400 that is another
exemplary embodiment in which a tapered longitudinal surface 447 is
provided on an inner wall of a drive nut 444. The exemplary fitting
of FIGS. 9 and 10 is a single ferrule design, similar to a single
ferrule tube fitting described in co-pending application Ser. No.
10/467,241, published under Pub. No. US 2006/0049632 and entitled
Tube Fitting for Stainless Steel Tubing, now U.S. Pat. No.
7,393,018, the entire disclosure of which is fully incorporated
herein by reference.
[0079] During pull-up of the illustrated tube fitting, axially and
radially inward movement of a nose of the single ferrule 480 may
cause an outer portion 480r of the front ferrule 480 to expand or
deflect outward. Under some circumstances, this outer portion 480r
of the ferrule 480 may contact an inner wall 446 of the drive nut
444 during pull-up, causing a radial reaction load between the
outer portion 480r of the ferrule 480 and the inner wall 446 of the
drive nut 244. In the exemplary embodiment of FIGS. 9 and 10, a
tapered longitudinal surfaces 447 is provided on the inner wall 446
at a location axially aligned with and radially spaced from the
ferrule 480. When the outer portion 480r of the ferrule 480
deflects during pull-up, as shown in FIG. 8, the outer portion 480r
may contact the tapered longitudinal surface 447, resulting in both
a radial and an axial component of reaction force. The tapered
condition of the inner wall surface (as opposed to, for example, a
cylindrical surface) can assist in separation of the nut 444 from
the ferrule 480 upon disassembly, as the axial component of
reaction force can assist in separation of the nut 444 from the
ferrule 480. Once the ferrule 480 is initially broken free from the
tapered wall surfaces 447, the nut 444 can be separated without any
substantial force, because of the taper angle of the tapered
longitudinal surface 447.
[0080] FIGS. 11 and 12 illustrate a fitting 500 that is yet another
exemplary embodiment in which a tapered longitudinal surface 548 is
provided on an inner wall of a drive nut 544. The exemplary fitting
of FIGS. 11 and 12 is a two-ferrule fitting of the type utilizing a
male threaded drive nut 544 and a female threaded fitting body 514,
similar to a tube fitting with male threaded drive nut described in
co-pending application Ser. No. 11/112,800, published under Pub.
No. US 2005/0242582 and entitled Fitting for Tube and Pipe, the
entire disclosure of which is fully incorporated herein by
reference.
[0081] During pull-up of the illustrated tube fitting, axially and
radially inward movement of a nose of the front ferrule 580 may
cause an outer portion 580r of the front ferrule 580 to expand or
deflect outward. Likewise, axially and radially inward movement of
the inner, gripping portion of the rear ferrule 582 may case an
outer portion 582r of the rear ferrule to expand or deflect
outward. Under some circumstances, one or both of these outer
portions 580r, 582r of the ferrules 580, 582 may contact an inner
wall 546 of the drive nut 544 during pull-up, causing a radial
reaction load between the outer portion 580r, 582r of the ferrule
or ferrules 580, 582 and the inner wall 546 of the drive nut 544.
In the exemplary embodiment of FIGS. 11 and 12, a tapered
longitudinal surface 547 is provided on the inner wall 546 at a
location axially aligned with and radially spaced from the ferrules
580, 582. When the outer portions 580r, 582r of the ferrules 580,
582 deflect during pull-up, as shown in FIG. 12, one or both of the
outer portions 580r, 582r may contact the tapered longitudinal
surface 547, resulting in both a radial and an axial component of
reaction force between the contacting surfaces. The tapered
condition of the inner wall surface 347 (as opposed to, for
example, a cylindrical surface) can assist in separation of the nut
544 from the ferrules 580, 582 upon disassembly, as the axial
component of reaction force can assist in separation of the nut 544
from the ferrule or ferrules 580, 582. Once the ferrule or ferrules
580, 582 are initially broken free from the tapered wall surfaces
547, the nut 544 can be separated without any substantial force,
because of the taper angle of the tapered longitudinal surface.
[0082] According to still another inventive aspect, assistance in
separating first and second fitting components may be accomplished
by reducing radially outward deflection of the second fitting
component during axial compression of the second fitting component,
to reduce radial reaction forces between the first and second
fitting components. For example, a counter-bowing feature may be
provided on a fitting body to reduce outward deflection or bowing
of a tube end during fitting assembly. In one embodiment having a
counter-bowing feature, a fitting component with a socket for
receiving a tube end may be provided with an axially receding
shoulder surface, or a shoulder having a surface that extends
axially and radially inward from an axially inner end of an axial
longitudinal wall surface of the socket.
[0083] FIG. 13 illustrates a fitting component 600 having a socket
610 with an annular longitudinal wall surface 612 and an axially
receding shoulder surface 615 that extends axially and radially
inward of an axially inner end of the longitudinal wall surface
612. When a tube end 674 is axially compressed in the tube socket
610 against an outer portion 616 of the shoulder surface 615, an
outward bowing force illustrated by arrows A tends to cause the
tube end 674 to bow or barrel outward into engagement with the
longitudinal wall surface 612. By axially receding the shoulder
surface 615 inward from the outer portion 616 that engages the tube
end 674, a gap G between an inner portion 676 of the tube end 674
and the shoulder 615 allows an inward pivoting force illustrated by
arrows B to at least partially counteract the bowing force A,
thereby reducing radial expansion of the tube end 674 due to bowing
or barreling. This reduced radial expansion of the tube end 674 may
facilitate separation of the tube end 674 from the fitting
component 600 during disassembly.
[0084] Many different types of axially receding shoulder surfaces
may be provided in a fitting component, including, for example,
frustoconical, concave, convex, or stepped surfaces, or
combinations of different contours or geometries, extending from
(either directly or radially spaced from) the annular longitudinal
wall surface. In the illustrated embodiment, the axially receding
shoulder surface 615 includes a frustoconical surface extending
from a substantially flat outer portion 616 of the shoulder surface
615, which extends to the longitudinal wall surface 612. This flat
outer portion may, for example, provide a tube end engaging surface
against which the tube end 674 bottoms out before or during axial
compression of the tube end.
[0085] This counter-bowing feature may be provided with many
different types of fitting components, including any fitting
component having a socket for receiving another fitting component,
such as a tube end, that experiences axial compression while
inserted in the socket, including, for example, a fitting
installation tool that pre-assembles or swages a tube gripping
member, such as a ferrule or ferrules, to a tube end prior to
fitting assembly. One example of such a fitting installation tool
to which these inventive aspects may be applied is a manually
operated hydraulic swaging unit described in U.S. Pat. No.
6,463,778 (the "'778 patent"), entitled "Apparatus for Swaging
Ferrules," the entire disclosure of which is incorporated herein by
reference.
[0086] FIG. 14 illustrates an exemplary tightening or swaging die
700 for use with a swaging tool, such as, for example, the
exemplary hydraulic swaging unit of the '778 patent. The swaging
die 700 includes a socket 710 having an axially outer camming
surface 711, an annular longitudinal wall surface 712, and an
axially receding shoulder surface 715, that extends axially and
radially inward from an inner end of the longitudinal wall surface
712. When a tube end 774 is axially compressed in the socket 710,
for example, due to axial advancement of the die 700, a gap G
between the axially receding shoulder surface 715 and an inner
portion 776 of the tube end 774 allows an inward pivoting force on
the axially compressed tube end 774 to at least partially
counteract a bowing force, thereby reducing radial expansion of the
tube end 774 due to bowing or barreling.
[0087] The gap G between the shoulder surface 715 and the inner
portion 776 of the tube end 774 may be sized to limit inward
pivoting of the tube end 774 during axial compression, and/or to
provide additional axial support for the axially compressed tube
end 774, by allowing at least part of the inner portion 776 of the
tube end 774 to engage the shoulder surface upon axial compression
of the tube end 774. For example, in one embodiment, the shoulder
surface 715 includes a tapered portion 717 that extend from an
outer portion 716 at an angle of approximately 75.degree. with
respect to an axial center line of the die 700.
[0088] Additionally, the surfaces of the socket 710 may, but need
not, be further configured to facilitate separation of the tube end
from the tool or swaging die 700 using one or more of the other
features described herein, such as, for example, a stepped or
tapered annular longitudinal surface to reduce radial reaction
forces and/or increase axial reaction forces between the tube end
774 and the die 700. For example, in the illustrated swaging die
700, the annular longitudinal wall surface 712 may be provided with
an intermediate tapered portion 713, to reduce radial reactions
force and/or increase axial reaction forces between the tube end
774 and the die 700. The angle of the tapered portion 713 may, but
need not, be relatively slight or over a relatively short axial
distance; for example, in one embodiment, for tubing having an
outer diameter of approximately 1.1 inches (28 mm), an intermediate
portion 713 is tapered at angle of approximately 0.67.degree. over
an axial length of approximately 0.088 inches (2.2 mm).
[0089] A counter-bowing feature may also be provided in a fitting
body to reduce radial reaction forces between a tube end and the
fitting body, thereby assisting in separation of the tube end from
the fitting body during fitting disassembly. FIGS. 15 and 16
illustrate an exemplary fitting assembly 800 including a
counter-bowing feature. The fitting assembly 800 includes a fitting
body 814 having a socket 810 for receiving a tube end 874. The
socket includes an annular longitudinal wall surface 812 and an
axially receding shoulder surface 815 that extends axially and
radially inward from an axially inner end of the longitudinal wall
surface 812. The fitting 800 may further include a drive nut 844
and ferrules 880, 882, which may, but need not, be consistent with
the nut 44 and ferrules 80, 82 of the fitting 10 of FIG. 1.
[0090] The fitting body 814 may be configured to receive the tube
end 874 such that the tube end 874 engages or bottoms out against
an outer portion of the shoulder 815 in the fitting's finger-tight
condition, or prior to axial compression of the tube end 874. In
another embodiment, the tube end 874 may engage a tapered tube
capture surface 852 in the fitting's finger tight condition,
resulting in a space between the shoulder surface 815 and the end
of the tube 874, as illustrated in FIG. 15. When the fitting 800 is
pulled up, as illustrated in FIG. 16, the tube end 874 is axially
compressed into engagement with the shoulder surface 815, at which
point a gap G between the axially receding shoulder surface 815 and
an inner portion 876 of the tube end 874 allows further axial
compression of the tube end 874 to produce inward pivoting forces
B, which at least partially counteract outward bowing forces A to
reduce the radial reaction forces between the fitting body 814 and
the tube end 874, thereby assisting in separation of the tube end
874 from the fitting body 814 during fitting disassembly. As with
the fitting installation tool die 700 of FIG. 14, the gap G may be
limited such that axial compression of the tube end 874 results in
additional axial support of the inner portion 876 of the tube end
874.
[0091] As with the tool die 700 described above, a socket 810 of a
fitting body 814 may, but need not, be further configured to
facilitate separation of the tube end 874 from the fitting body 814
using one or more of the other features described herein, such as,
for example, a stepped, tapered, or recessed annular longitudinal
surface to reduce radial reaction forces and/or increase axial
reaction forces between the tube end 874 and the fitting body 814,
as shown, for example, in the exemplary embodiments of FIGS.
1-6.
[0092] While various inventive aspects, concepts and features of
the inventions may be described and illustrated herein as embodied
in combination in the exemplary embodiments, these various aspects,
concepts and features may be used in many alternative embodiments,
either individually or in various combinations and sub-combinations
thereof. Unless expressly excluded herein all such combinations and
sub-combinations are intended to be within the scope of the present
inventions. Still further, while various alternative embodiments as
to the various aspects, concepts and features of the
inventions--such as alternative materials, structures,
configurations, methods, circuits, devices and components,
software, hardware, control logic, alternatives as to form, fit and
function, and so on--may be described herein, such descriptions are
not intended to be a complete or exhaustive list of available
alternative embodiments, whether presently known or later
developed. Those skilled in the art may readily adopt one or more
of the inventive aspects, concepts or features into additional
embodiments and uses within the scope of the present inventions
even if such embodiments are not expressly disclosed herein.
Additionally, even though some features, concepts or aspects of the
inventions may be described herein as being a preferred arrangement
or method, such description is not intended to suggest that such
feature is required or necessary unless expressly so stated. Still
further, exemplary or representative values and ranges may be
included to assist in understanding the present disclosure;
however, such values and ranges are not to be construed in a
limiting sense and are intended to be critical values or ranges
only if so expressly stated. Moreover, while various aspects,
features and concepts may be expressly identified herein as being
inventive or forming part of an invention, such identification is
not intended to be exclusive, but rather there may be inventive
aspects, concepts and features that are fully described herein
without being expressly identified as such or as part of a specific
invention, the inventions instead being set forth in the appended
claims. Descriptions of exemplary methods or processes are not
limited to inclusion of all steps as being required in all cases,
nor is the order that the steps are presented to be construed as
required or necessary unless expressly so stated.
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