Hose coupling and method of constructing same

A hose coupling, and method of constructing same, for sealably interconnecting a flexible hose and a rigid center pipe. The hose coupling is assembled without requiring relative rotation between the rigid center pipe and the inner surface of the flexible hose. The method includes the steps of inserting an end of the center pipe rectilinearly into the opening of the flexible hose, disposing a compression sleeve member having first and second outwardly facing frustoconical surfaces about the flexible hose, disposing first and second complementary threaded tubular members, which respectively define first and second outwardly facing frustoconical surfaces, about the flexible hose and rigid center pipe, respectively, and threadably drawing the first and second complementary threaded tubular members together such that the first and second outwardly inwardly facing frustoconical surfaces respectively force the first and second outwardly facing frustoconical surfaces inwardly to compress the compression member tightly about the flexible hose and the center pipe. The hose coupling includes the compression sleeve member, the first and second complementary threaded tubular members, and the cooperative frustoconical surfaces which force the compression sleeve member to a smaller stressed diameter which securely and sealably interconnects the rigid pipe member and flexible hose.

TECHNICAL FIELD 
The invention relates in general to a hose coupling, and a method of 
constructing same, for sealably interconnecting a rigid pipe member and a 
resilient hose member. 
BACKGROUND ART 
Flexible hoses have been developed for the refrigeration and air 
conditioning industry which have an inner liner designed to inhibit 
permeation of refrigerant through the hose wall. Such hoses, such as 
Aeroquip's FC505 hose, reduce liberation of chlorofluorocarbon (CFC) 
refrigerants to the atmosphere, thought to be harmful to the earth's ozone 
layer. The inner liner, for example, may include a thin layer of a 
polyamide polymer, such as a polyamide from the nylon family. 
It is common in the refrigeration industry to utilize a hose fitting or 
hose coupling which sealingly interconnects a rigid center pipe and a 
flexible hose, including the insertion of the rigid center pipe into the 
hose opening. This interconnection often requires relative rotation 
between the rigid center pipe and flexible hose as the rigid center pipe 
is forced to the desired dimension within the hose opening. Such relative 
rotation, however, can damage the inner liner of the aforesaid 
refrigeration hoses, defeating the purpose of such hoses. 
Thus, it is desirable, and it is an object of the present invention, to 
provide a new and improved hose coupling, and method of constructing same, 
which will provide a reliable sealed joint between a rigid center pipe and 
a flexible hose, without causing damage to hoses of the type which include 
an inner liner. 
It would also be desirable, and it is another object of the present 
invention, to provide a new and improved hose coupling, and method of 
constructing same, which, in addition to preventing damage to hoses having 
an inner liner, permit disassembly and re-use of the components used in 
the hose coupling. 
SUMMARY OF THE INVENTION 
Briefly, the invention includes a method of sealably interconnecting a 
rigid center pipe and a flexible hose, with the rigid center pipe having a 
first end, and with the flexible hose having an inner surface which 
defines an opening which starts at a first end of the flexible hose. The 
method includes the steps of inserting the first end of the rigid center 
pipe rectilinearly into the opening at the first end of the flexible hose, 
and dimensioning the rigid center pipe such that the rigid center pipe 
enters the flexible hose without damaging the inner surface of the 
flexible hose. The method further includes providing a compression sleeve 
member having first and second axial ends, a central axis which extends 
between the first and second ends, and first and second outwardly facing 
frustoconical surfaces which respectively start at the first and second 
axial ends and taper away from the central axis, and disposing the 
compression sleeve member about a portion of the flexible hose which 
surrounds the rigid center pipe. The method further includes the steps of 
providing first and second tubular members having complementary threaded 
portions, with the first and second tubular members respectively defining 
first and second inwardly facing frustoconical surfaces, and disposing the 
first and second tubular members about the flexible hose and rigid center 
pipe, respectively, such that the first and second inwardly facing 
frustoconical inner surfaces respectively taper in the same directions as 
the first and second outwardly facing frustoconical surfaces of the 
compression sleeve member. The method then includes the steps of engaging 
the complementary threaded portions of the first and second tubular 
members such that threadable engagement initiates contact between the 
first inwardly facing frustoconical surface and the first outwardly facing 
frustoconical surface, and between the second inwardly facing 
frustoconical surface and the second outwardly facing frustoconical 
surface, and drawing the first and second tubular members together by 
progressive threadable engagement of the complementary threaded portions 
of the first and second tubular members such that the first and second 
inwardly facing frustoconical surfaces respectively force the first and 
second outwardly facing frustoconical surfaces inwardly, to compress the 
compression sleeve member tightly about the flexible hose and the rigid 
center pipe. 
The invention further includes a hose coupling for sealably interconnecting 
a flexible hose and a rigid center pipe. The flexible hose includes a 
first end, an external surface, and an internal surface which defines an 
opening which starts at a first end of the flexible hose The rigid center 
pipe includes a first end disposed within the opening of the flexible 
hose, with the rigid center pipe being dimensioned such that insertion of 
the rigid center pipe into the opening of the flexible hose will provide a 
close fit without damage to the internal surface of the flexible hose. The 
hose coupling includes a compression sleeve member disposed about the 
flexible hose and a portion of the rigid center pipe disposed therein. The 
compression sleeve member has first and second axial ends, an inner 
surface defining an unstressed first diameter selected to enable the 
compression sleeve member to be selectively positioned on the flexible 
hose, a substantially C-shaped cross-sectional configuration which enables 
the compression sleeve member to be forcibly compressed to a smaller 
second diameter, and an outer surface which includes first and second 
outwardly facing frustoconical surfaces which respectively start with a 
first diameter adjacent to the first and second axial ends and taper 
outwardly to a second and larger diameter intermediate the first and 
second axial ends. The hose coupling further includes first and second 
tubular members each having first and second axial ends. The first tubular 
member has a threaded outer surface which extends inwardly from the second 
axial end, and an inner surface dimensioned to enable the first tubular 
body member to be selectively positioned on the flexible hose. The inner 
surface of the first tubular member defines a cylindrical first portion 
which starts at the first axial end with a first diameter, and an inwardly 
facing frustoconical second portion which starts with a larger second 
diameter adjacent to the second axial end, and which tapers inwardly 
towards the cylindrical first portion. The second tubular member has an 
inner surface dimensioned to enable the second tubular member to be 
selectively positioned on the rigid center pipe. The inner surface of the 
second tubular member defines a cylindrical first portion which has 
internal threads complementary to the external threads of the first 
tubular member, and an inwardly facing frustoconical second portion which 
starts adjacent to the cylindrical first portion and tapers inwardly 
towards the second axial end. The first and second tubular members are 
threadably coupled about the compression sleeve member such that the 
inwardly facing frustoconical surfaces of the first and second tubular 
members respectively engage the first and second outwardly facing 
frustoconical surfaces of the compression sleeve member and force the 
compression sleeve member to the stressed smaller second diameter, to 
compress the flexible hose tightly about a portion of the rigid center 
pipe which is disposed within the opening of the flexible hose and provide 
a sealed interconnection between the flexible hose and the rigid center 
pipe.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings, FIG. 1 illustrates a cross sectional view of 
a hose fitting or coupling 10 constructed according to the teachings of 
the invention, and FIG. 2 is a partially exploded view of the hose 
coupling 10, which more clearly illustrates the components of hose 
coupling 10 during a method step in the assembly of hose coupling 10. Both 
FIGS. 1 and 2 will be referred to during the following description of the 
invention. 
Hose coupling 10 sealingly joins a resilient flexible hose 12, such as a 
freon or refrigerant hose used in the refrigerant and air conditioning 
industry, with a rigid, preferably metallic, center pipe 14. Flexible hose 
10 is preferably of the type which has an internal membrane or liner 16, 
although hose coupling 10 is suitable for use with either lined or unlined 
flexible hoses. 
Flexible hose 12 has a first end 18 and inner and outer surfaces 20 and 22, 
respectively, with the inner surface 20 defining a longitudinally 
extending center opening 24 having a predetermined diameter. The inner and 
outer surfaces 20 and 22 thus define a resilient, deformable wall portion 
23 therebetween. 
Rigid center pipe 14 has a first end 26, and inner and outer surfaces 28 
and 30, respectively, with the inner surface 28 defining a longitudinally 
extending center opening 32 having a predetermined diameter. Rigid center 
pipe 14 further includes an outwardly extending radial shoulder 34 having 
first and second axial ends 36 and 38, respectively. The first axial end 
36 is spaced from the first end 26 of rigid center pipe 14 by a dimension 
selected to determine the desired extension of rigid center pipe 14 into 
the opening 24 of flexible hose 12. 
Rigid center pipe 14 further preferably includes friction enhancing means 
disposed between the first end 26 of the rigid center pipe and the first 
axial end 36 of radial shoulder 34. While the friction enhancing means may 
include a knurling of the outer surface 30 between the first end 26 and 
the first axial end 36 of radial shoulder 34, the friction enhancing means 
is preferably in the form of an outwardly extending annular bead 40, as 
illustrated in the Figures. Annular bead 40 is preferably disposed 
approximately midway between the first end 26 and the first axial end 36 
of radial shoulder 34. 
For purposes of example, hose coupling 10 may interconnect a refrigerant 
compressor with a refrigerant condenser in a refrigeration or air 
conditioning application, with rigid center pipe 14 being connected to a 
discharge port of the compressor and with flexible hose 12 being connected 
to an input header of a condenser, but it is to be understood that 
coupling 10 is suitable for sealably joining any flexible hose 12 and 
rigid center pipe 14 in any application thereof. 
In addition to the flexible hose 12 and rigid center pipe 14, hose coupling 
10 requires only three additional components, a compression sleeve member 
42 and first and second complementary threaded tubular members 44 and 46. 
Compression sleeve member 42 and the first and second tubular members 44 
and 46 are preferably metallic, such as plated steel, brass, or stainless 
steel. 
Compression sleeve member 42, which also may be called a "crush sleeve" or 
"crush ring", is a tubular member having a central axis 48, first and 
second axial ends 50 and 52, and inner and outer surfaces 54 and 56, 
respectively. Compression sleeve member 42 includes a longitudinally 
extending gap 58 in its wall which extends between the first and second 
axial ends 50 and 52. Thus, compression sleeve member has a substantially 
C-shaped cross sectional configuration when viewing a cross section taken 
on a plane which is perpendicular to the longitudinally extending center 
axis 48. The dimension of gap 58 is selected to limit the amount of 
compressive forces which may be applied to flexible hose 12 and the 
portion of rigid center pipe 14 disposed within the opening 24 of flexible 
hose 12, to prevent crushing and thus constricting rigid center pipe 14. 
The inner surface 54 of compression sleeve member 42 defines a 
longitudinally extending opening 60 which may define a constant diameter, 
especially when the friction enhancing means is in the form of a knurled 
surface; or, as illustrated in FIG. 1, opening 60 may have a predetermined 
minimum diameter at the first and second axial ends 50 and 52 of 
compression sleeve member 42, with the inner wall 54 then curving slightly 
outward, which configuration is especially suitable when the friction 
enhancing means includes annular bead 40, to generate more uniform 
compressive forces on the annular bead 40 and the adjacent straight 
portions of the outer surface 30 of rigid center pipe 14. The unstressed 
minimum dimension of the inner diameter of compression sleeve member 42 is 
selected to enable compression sleeve member 42 to be telescoped over the 
first end 18 of flexible hose 12 and selectively positioned thereon. 
The outer surface 56 of compressive sleeve member 42 includes first and 
second outwardly facing frustoconical surfaces 62 and 64 which 
respectively start adjacent to the first and second axial ends 50 and 52 
of compression sleeve member 42 and they taper outwardly, away from the 
center axis 48, as the first and second outwardly facing frustoconical 
surfaces 62 and 64 extend toward the longitudinal midpoint of the 
compression sleeve member 42. 
The first complementary tubular member 44 has a longitudinal center axis 
which coincides with center axis 48 when assembled in the hose coupling 
10, with center axis 48 extending between first and second axial ends 66 
and 68, respectively. Tubular member 44 includes a threaded outer surface 
70 which starts adjacent to the second axial end 68 and extends for a 
predetermined dimension towards the first axial end 66. The remaining 
outer surface 71 between the threaded outer surface 70 and the first axial 
end 66 has a configuration which enables tubular member 44 to be held, or 
rotated, by a suitable tool. 
The first complementary threaded tubular member 44 has an inner surface 
which extends between the first and second axial ends 66 and 68, which 
inner surface includes a cylindrical first portion 72 which starts 
adjacent to the first axial end 66 with a first diameter, and it extends 
towards the second axial end for a predetermined dimension. The inner 
surface then flares outwardly to define an inwardly facing frustoconical 
second portion or surface 74 which then extends to a point adjacent to the 
second axial end 68 of the first tubular member 44. The first inner 
diameter is selected to enable tubular member 44 to be telescoped over the 
first end 18 of flexible hose 12 and adjustably positioned thereon. 
The second complementary threaded tubular member 46 has a longitudinal 
center axis which coincides with center axis 48 when assembled in the hose 
coupling 10, with center axis 48 extending between first and second axial 
ends 76 and 78, respectively. Tubular member 46 includes a threaded, 
cylindrical inner surface 80 which starts adjacent to the first axial end 
76 and extends for a predetermined dimension towards the second axial end 
78. The threads of the internal threaded portion 80 are complementary to 
the threads of the external threaded portion 70 of the first tubular 
member 44. The inner surface of the second tubular member 46 then steps 
inwardly to the start of an inwardly facing frustoconical portion 82 which 
tapers inwardly as the frustoconical portion 82 extends towards the second 
axial end 78. 
The inner surface of the second tubular member 46 then defines a 
cylindrical portion 84 which proceeds towards the second axial end 78 for 
a predetermined dimension, at which point the inner surface of the second 
tubular member 46 steps inwardly to create a flange 86 having a flange 
surface 88. The inner surface then continues with a cylindrical surface 90 
to the second axial end 78. The diameter defined by cylindrical surface 90 
is selected to enable the second tubular member 46 to be telescoped over 
the second end 92 of the rigid center pipe and adjustably positioned 
thereon. The inner diameter of cylindrical surface 90 also provides a 
flange surface 88 which is large enough to contact the second axial end 38 
of radial shoulder 34, to limit the movement of the second tubular member 
46 towards the first end 26 of the rigid center pipe 14. If the second end 
92 is to be provided With a flare nut, for example, such as for connection 
to a refrigerant compressor, then the second tubular member 46 is 
positioned on rigid center pipe 14 before the flare nut is attached. 
The second complementary threaded tubular member 46 has an outer surface 
which extends between the first and second axial ends 76 and 78, including 
a first outer surface portion 94 which starts at the first axial end 76 
and extends towards the second axial end 78 for a predetermined dimension, 
with the first outer surface portion 94 being configured to enable the 
second tubular member 46 to be held, or rotated, by a suitable tool. The 
remaining outer surface 96 from the end of the first outer surface portion 
94 to the second axial end 78, may have any suitable configuration. 
In the assembly of the components to form hose coupling 10, the first 
tubular member 44 is telescoped over the first end 18 of flexible hose 12 
such that the second axial end 68 of the first tubular member 44 is closer 
to the first end 18 of the flexible hose 12 than the first axial end 66. 
In like manner, the compression sleeve member 42 is telescoped over the 
first end 18 of flexible hose 12 such that the second axial end 52 of the 
compression sleeve member 42 is closer to the first end 18 of the flexible 
hose 12 than the first axial end 50. The frustoconical surfaces 62 and 74 
of the compression sleeve member and of the first tubular member 44 will 
thus taper in the same direction. 
The second tubular member 46 is telescoped over the second end 92 of the 
rigid center pipe 14 such that the first axial end 76 of the second 
tubular member 46 is closer to the first end 26 of the rigid center pipe 
14 than the second axial end 78. Thus, when the rigid center pipe 14 is 
assembled with flexible hose 12, the frustoconical surfaces 64 and 82 of 
the compression sleeve member 42 and of the second tubular member 46 will 
taper in the same direction. 
The first end 26 of the rigid center pipe 14 is then inserted into opening 
24 at the first end 18 of flexible hose 12, with care being taken to 
utilize a rectilinear movement, rather than a twisting movement. The rigid 
center pipe 14 and annular bead 40 are dimensioned to enable a rectilinear 
movement to be used, providing as close fit as possible while obviating 
the need to provide relative twisting between the rigid center pipe 14 and 
flexible hose 12 to enable rigid center pipe 14 to be inserted for the 
desired insertion dimension, i.e., until the first end 18 of the flexible 
hose 12 contacts the first axial end 36 of radial shoulder 34. When the 
relative dimensions between the rigid center pipe 14 and the diameter of 
opening 24 in flexible hose 12 are such that the desired insertion 
dimension can only be achieved by relative twisting action between the 
components, an inner liner or membrane in flexible hose 12, such as liner 
16, may be damaged, destroying the effectiveness of liner 16 in preventing 
permeation of chemicals through the wall of flexible hose 12. 
The compression sleeve member 42 is then positioned on flexible hose 12 
such that the second axial end 52 thereof is immediately adjacent to the 
first axial end 36 of radial shoulder 34. The outer diameter of radial 
shoulder 34 may be slightly larger than the diameter of the opening in 
compression sleeve member 42, enabling the second axial end 52 of the 
compression sleeve member 42 to be butted against the first axial end 36 
of radial shoulder 34. This positioning of compression sleeve member 42 
automatically centers the compression sleeve member 42 over the portion of 
rigid center pipe 14 which extends into flexible hose 12, including the 
centering of the compression sleeve member 42 relative to the annular bead 
40, when an annular bead is used as the friction enhancing means. 
The first tubular member 44 is then moved to the right in the view of FIG. 
2, until the inwardly facing frustoconical surface 74 contacts the 
outwardly facing frustoconical surface 62 of compression sleeve member 42. 
The radial flange 34 thus provides the function of ensuring proper 
alignment of the various components of hose coupling 10, locating the 
first end 18 of the flexible hose 12 and the second axial end 52 of the 
compression sleeve member 42 against the first axial end 36, and locating 
the inwardly facing frustoconical surface 74 of the first tubular member 
44 against the outwardly facing frustoconical surface 62 of compression 
sleeve member 42. 
The second tubular member 46 is then moved toward the first end 26 of the 
rigid center pipe 14 until the first axial end 76 thereof contacts the 
second axial end 68 of the first tubular member. The first and second 
tubular members 44 and 46 are then threadably engaged, preferably by 
holding the first tubular member 44 and rotating the second tubular member 
46. As the first and second tubular members 44 and 46 are drawn together 
by progressive threadable engagement, the inwardly facing frustoconical 
surfaces 74 and 82 of the first and second tubular members 44 and 46 
respectively contact and ride up the outwardly facing frustoconical 
surfaces 62 and 64 of the compression sleeve member 42, forcing the 
compression sleeve member 42 to a smaller stressed inner diameter which 
results in tightly compressing and inwardly deforming the resilient wall 
portion 23 of the flexible hose 12 about the portion of rigid center pipe 
14 which is surrounded by compression sleeve member 42. When the gap 58 is 
closed, the desired holding and sealing pressure is obtained, and no 
further pressure can be applied to the portion of the rigid center pipe 14 
disposed within the opening 24 of the flexible hose 12. 
In summary, a hose coupling 10 has been formed according to the teachings 
of the invention, which includes a method of assembling hose coupling 10, 
without requiring relative twisting between the rigid center pipe 14 and 
the inner surface 20 of the flexible hose 12. Thus, hose coupling 10 may 
be used to couple a rigid center pipe 14 and a flexible hose 12 having an 
inner liner or membrane 16, without danger of rupturing or otherwise 
damaging the inner liner 16. Further, simply threadably disengaging the 
first and second tubular members 44 and 46 and separating them enables the 
compression sleeve member 42 to return to its unstressed configuration. 
These components may then be used to construct another hose coupling 10.