U.S. patent application number 09/930282 was filed with the patent office on 2002-02-28 for connector for flexible pipes having at least one resilient sealing ring.
This patent application is currently assigned to Manuli Auto Italia S.p.A.. Invention is credited to Manuli, Dardanio.
Application Number | 20020024218 09/930282 |
Document ID | / |
Family ID | 11339589 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020024218 |
Kind Code |
A1 |
Manuli, Dardanio |
February 28, 2002 |
Connector for flexible pipes having at least one resilient sealing
ring
Abstract
A connector (10) for flexible pipes, particularly for use in
cooling or air-conditioning systems for motor vehicles, comprises a
hollow main body including a coupling element (13) for a flexible
pipe, the coupling element having at least one gripping tooth (16a,
16b) for cooperating with clamping means (6) to grip a flexible
pipe (14) when the connector is in the condition of use. The
connector comprises at least one sealing ring (17) having a
substantially cylindrical inside wall (18) and a shaped, preferably
arcuate, outside wall (19). The sealing ring (17) exhibits
resilient behavior in a radial direction and is compressed
radially, when the connector (10) is in the condition of use, by
the flexible pipe (14) which is fitted and clamped on the coupling
element (13) by the clamping means (6).
Inventors: |
Manuli, Dardanio; (Milano,
IT) |
Correspondence
Address: |
ARENT FOX KINTNER PLOTKIN & KAHN
1050 CONNECTICUT AVENUE, N.W.
SUITE 600
WASHINGTON
DC
20036
US
|
Assignee: |
Manuli Auto Italia S.p.A.
|
Family ID: |
11339589 |
Appl. No.: |
09/930282 |
Filed: |
August 16, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09930282 |
Aug 16, 2001 |
|
|
|
08750225 |
Nov 22, 1996 |
|
|
|
Current U.S.
Class: |
285/256 |
Current CPC
Class: |
F16L 33/02 20130101;
F16L 33/2076 20130101 |
Class at
Publication: |
285/256 |
International
Class: |
F16L 033/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 1994 |
IT |
BO 94 U 000102 |
May 23, 1995 |
EP |
PCT/EP95/01947 |
Claims
In the claims:
1. A connector for flexible pipes, particularly for use in cooling
or air-conditioning systems for motor vehicles, of the type
comprising a hollow main body including a coupling element (13) for
a flexible pipe, the coupling element having at least one gripping
tooth (16a, 16b, 21) for cooperating with clamping means (6, 251 to
grip a flexibly pipe (14) when the connector (10) is in the
condition of use, characterized in that it comprises at least one
sealing ring (17) having a substantially cylindrical inside wall
and a shaped outside wall (19), the sealing ring (17) exhibiting
resilient behaviour in a radial direction and being compressible
radially, when the connector (10) is in the condition, by the
flexible pipe (14) which is fitted and clamped on the coupling
element (13) by the clamping means (6, 25).
2. A connector for flexible pipes according to claim 1,
characterized in that the width (H) of the sealing ring (17) is
greater than its thickness (S).
3. A connector for flexible pipes according to claim 1,
characterized in that the sealing ring (17) is resiliently
force-fitted in an annular recess (20) in the coupling element
(13).
4. A connector far flexible pipes according to claim 2 and claim 3,
characterized in that the width of the annular recess (20) is
greater than the width (H) of the sealing ring, and in that the
depth of the annular recess is less than the thickness (S) of the
sealing wing.
5. A connector for flexible pipes according to claim 3,
characterized in that the annular recess (20) is disposed
downstream, in the direction in which the flexible pipe (14) is
fitted, of at least one gripping tooth (16a, 15b, 21) and is
substantially adjacent thereto.
6. A connector for flexible pipes according to claim 5,
characterized in that the sealing ring (17) projects radially
relative to the coupling element (13), and in that the gripping
tooth comprises at least one ramp-like, annular tooth (16a, 16b,
21) which projects radially relative to the sealing ring (17).
7. A connector for flexible pipes according to claim 1,
characterized in that the outside wall (19) of the sealing ring
(17) has an arcuate profile in longitudinal section.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a connector for flexible
pipes, particularly for use in cooling or air-conditioning systems
for motor vehicles, of the type comprising a hollow main body
including a coupling element for a flexible pipe, the coupling
element having at least one gripping tooth for cooperating with
clamping means to grip the flexible pipe when the connector is in
the condition of use.
[0003] 2. Description of the Related Art
[0004] An example of a connector of the known type indicated above
is illustrated and generally indicated 1 in the appended FIG. 1.
This connector has a tubular coupling element 2 on which two
ramp-like, annular teeth 3 and two pairs of sealing collars 4 are
formed integrally. In use, the end of a flexible pipe 5 is fitted
and clamped on the coupling element 2 by the plastic deformation of
a collar 6 which, in the example of FIG. 1, is constituted by a
pair of bands 7 connected in a tandem configuration by a transverse
plate 8.
[0005] A disadvantage of known connectors is that the
characteristics of the seal between the pipe and the coupling
element for preventing the escape or leakage of the operating fluid
are not entirely satisfactory when the fluid has small molecular
dimensions.
[0006] This problem is accentuated by the fact that, in order to
reduce the permeability of the pipes to fluids of this type,
flexible pipes having an internal sheathing of polyamide material,
particularly nylon, are often used.
[0007] As is known, polyamide materials generally have poor
flexibility characteristics and hence a poor ability to adapt to
the gripping teeth of the coupling elements of the connectors,
particularly to ramp-like annular teeth, with the risk of imperfect
adhesion between the inside wall of the pipe and the coupling
element, although only in a localized region.
[0008] Another disadvantage of known connectors connected to
flexible pipes having an internal polyamide sheathing is caused by
the difference between the coefficient of thermal expansion of the
sheathing and that of the metal of which the connector, including
any sealing collars, is made. This difference between the
coefficients of thermal expansion means that the coupling element
of the connector tends to contract radially to a greater extent or
more rapidly than the flexible pipe as a result of abrupt
reductions in the running temperature, with the consequent danger
of the fluid leaking.
SUMMARY OF THE INVENTION
[0009] The object of the present invention is to overcome the
aforesaid problems by means of a connector of the type indicated in
the introduction to the present description, characterized in that
it comprises at least one sealing ring having a substantially
cylindrical inside wall and a shaped outside wall, the sealing ring
exhibiting resilient behaviour in a radial direction and being
compressible radially, when the connector is in the condition of
use, by the flexible pipe which is fitted and clamped on the
coupling element by the clamping means.
[0010] An advantage of the connector according to the present
invention is that its fluidtightness is ensured even in the
presence of any geometrical defects or surface faults either of the
coupling element or of the passage inside the flexible pipe,
reducing production costs by virtue of the lower incidence of
rejects. In fact, by virtue of the sealing ring, the fluidtightness
of the connector is not affected by lack of adhesion of the
flexible pipe to the coupling element in a localized region
thereof.
[0011] Another advantage of the connector according to the present
invention results from the fact that, even in difficult conditions
of use, it is not necessary to increase the force with which the
flexible pipe is clamped onto the connector to ensure a
satisfactory seal and the risk of undesired deformation or breakage
of the coupling element or of the internal polyamide sheathing,
when it is present, is thus reduced.
[0012] If the connector according to the present invention is used
with a flexible pipe having an internal polyamide sheathing,
another advantage is achieved; in this case, the friction between
the sealing ring and the polyamide sheathing, which is undoubtedly
greater than the friction which normally arises between the
sheathing and the metal of known connectors, effectively stops any
relative rotation between the connector and the pipe when clamping
has been effected. The risk of fluid leaking or escaping is thus
undoubtedly reduced.
[0013] According to another characteristic of the present
invention, the sealing ring is housed with a resilient forced fit
in an annular recess in the coupling element.
[0014] An advantage resulting from this characteristic is that the
fitting of the sealing ring on the coupling element is quick and
easy to do and can easily be automated. Moreover, the longitudinal
position of the sealing ring on the coupling element is defined at
the design stage so as to optimize the sealing characteristics of a
certain model of connector according to the type of clamping means
used for the flexible pipe.
[0015] According to a further characteristic of the connector
according to the present invention, the outside wall of the sealing
ring is substantially arcuate in shape.
[0016] Two advantages result from this further characteristic; on
the one hand, it prevents the sealing ring from being displaced or
rolled up when the flexible pipe is fitted on the coupling element
since the convex shape of its outside wall favours the sliding of
the flexible pipe thereon, as long as it is not clamped; on the
other hand, the compression force exerted on the sealing ring
radially by the flexible pipe clamped onto the coupling element is
preferably discharged uniformly onto the sides of the sealing ring,
bringing about, amongst other things, a more progressive resilient
action and a greater useful travel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Further characteristics and advantages of the present
invention will become clear from the detailed description which
follows, with reference to the appended drawings, given by way of
non-limiting example, in which:
[0018] FIG. 1 is an exploded side view of a connector, a clamping
collar and a flexible pipe of the prior art which have already been
discussed briefly in the introduction to the present
description,
[0019] FIG. 2 is a side view similar to FIG. 1 of a connector
according to the present invention.
[0020] FIG. 3 is an enlarged, partial longitudinal section of a
detail of the connector of FIG. 1 or of the variant thereof of FIG.
4, showing the sealing ring, and
[0021] FIG. 4 is a partially-sectioned side view of a variant of
the connector of the present invention in the assembled
configuration.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0022] With reference now to the drawings, FIG. 1 shows a known
connector, the characteristics of which have already been described
above in the introduction to the present description. In this
drawing, the direction in which the components (the connector, the
clamping collar and the flexible pipe) are assembled when the
connector is in use is shown by the arrows X.
[0023] FIG. 2 shows a connector according to the present invention,
comprising an elongate, hollow body, generally indicated 10, having
an internally threaded opening at its end which is on the left in
the drawing. A nut 12 is formed integrally on the connector 10 to
enable the opening 11 to be screwed onto a corresponding rigid
threaded member of the system in which the connector is used. At
the opposite end to the opening 11, the connector 10 has a tubular
coupling element 13 for the fitting of a flexible pipe 14 of known
type.
[0024] An intermediate tubular portion 15 having an outside
diameter larger than the outside diameter of the coupling element
13 is preferably interposed between the coupling element 13 and the
nut 12. Two annular ramp-like teeth 16a, 16b are spaced apart on
the outside wall of the coupling element 13, one tooth (16a) being
disposed near the end 13a of the coupling element 13 and the other
tooth (16b) in a position intermediate the first tooth 16a and the
intermediate tubular portion 15. The teeth 16a, 16b cooperate with
a clamping element of known type such as, for example, the collar 6
which has bands 7 in tandem, so as to prevent the flexible pipe 14
from coming off the connector 10 when, with the connector in the
assembled condition, the bands 7 are tightened onto the flexible
pipe 5 by plastic deformation so as to deform or squash it locally
in regions corresponding to the teeth 16a, 16b.
[0025] Two resilient sealing rings 17 are fitted on the coupling
element 13, near respective teeth 16a, 16b, on the opposite sides
to the end 13a of the coupling element 13 and in substantially
predetermined axial positions. Naturally, since the configuration
of FIG. 2 is given by way of example, an alternative solution for
the connector according to the present invention may be limited
simply to the formation of a single tooth and to the provision of a
single corresponding sealing ring 17.
[0026] As shown in detail in FIG. 3, each sealing ring 17 is
constituted by a ring of resilient material, preferably rubber,
having a substantially cylindrical inside wall 18 and an outside
wall 19 with a shaped cross-section. In particular, in the
embodiment shown in the drawing, the outside wall 19 is curved like
a barrel so as to have a symmetrical arcuate profile in
cross-section. The profile of the outside wall 19 is not limited to
an arcuate shape and may be configured with a profiled shape which,
in any case, is selected on the basis of the conditions of use of
the connector and of the characteristics of the associated flexible
pipe. More specifically, the outside wall 19 may effectively be
shaped with a recessed arcuate, sloping, or arrow-head profile or
may have more or less accentuated corrugations.
[0027] The inside diameter of the sealing ring 17 is smaller than
the diameter of the base of an annular recess 20 in the coupling
element 13 so that the sealing ring 17 can be fitted in the annular
recess 20 with a certain degree of radial forcing owing to the
resilience of the sealing ring. The annular recess 20 is wider than
the sealing ring 17, for reasons which will become clearer from the
following.
[0028] In a preferred embodiment, the width H of the cross-section
of the sealing ring 17 is greater than its thickness S so that the
sealing ring has positional stability which opposes its rolling on
the coupling element when it is acted on by a longitudinal force,
for example, during the fitting of the flexible pipe or during the
fitting of the sealing ring on the coupling element.
[0029] When the connector 10 is in the disassembled condition, as
can be seen in FIGS. 2 and 3, the sealing ring 17 projects radially
relative to the cylindrical surface of the coupling element 13. In
a preferred solution, the sealing ring 17 projects radially to a
lesser extent than the teeth 16a, 16b; in other words, the height D
of the teeth 16a or 16b with respect to the base of the annular
recess 20 is greater than the thickness S of the sealing ring
17.
[0030] FIG. 4 shows a variant of the connector according to the
present invention in an assembled condition of use, in which a row
of ramp-like, annular teeth 21 arranged in a continuous series
starting from the end 13a is formed on the coupling element 13. A
single sealing ring 17 is fitted on the coupling element 13 between
the row of teeth 21 and the intermediate tubular element 15,
preferably near the last tooth 21 of the row, illustrated with
broken line in FIG. 3. The flexible pipe 14 is fitted on the
coupling element 13 so that its end 14a extends beyond the axial
position of the sealing ring 17. The flexible pipe shown in FIG. 4
comprises an outer rubber covering 22 in which a reinforcing braid
23, preferably made of steel wire, is incorporated, and a tubular
lining 24 of polyamide, particularly nylon.
[0031] In this embodiment, the element for clamping the pipe to the
connector is constituted by a collar 25 having an end shoulder 26
which, in the assembled condition shown, abuts the intermediate
tubular portion 15 of the connector. Like the collar 6 of FIG. 2,
the collar 25 is clamped onto the flexible pipe 14 by plastic
deformation so as to bring about localized deformation or squashing
thereof in regions corresponding to the row of teeth 21 and to
rings 27 formed in the inside wall of the collar 25.
[0032] If the annular teeth 16a, 16b, 21 project radially further
than the sealing rings 17 and the latter are positioned downstream
of the teeth with reference to the direction in which the flexible
pipe is fitted, as shown in the embodiment of FIG. 2, axial
stresses or displacement of the sealing rings 17 when the flexible
pipe is fitted on the coupling element 13 are prevented. Arcuate
profiles of the outside walls of the sealing rings 17 also favour
the fitting of the flexible pipe onto the coupling element. The
sliding of the flexible pipe unto the sealing rings 17 is also
facilitated if the pipe has an internal polyamide sheathing 24 with
a low coefficient of friction.
[0033] In any case, axial sliding of the sealing rings 17 is
generally prevented or greatly limited by the friction between
their inside walls 18 and the coupling element 13, particularly the
bases of the respective recesses 20, this friction being favoured
by the relatively large extent of the contact zone and by the
resilient compression force exerted by the sealing rings on the
coupling element.
[0034] When the flexible pipe 14 is fitted on the coupling element,
it is clamped, as described above, by the radial plastic
deformation of the collars 6 or 25, for example, by clinching or
rolling. Naturally, the pipe 14 can be fixed to the connector by
any of the known techniques usually used in this field such as, for
example, even by means of reclaimable connections with shells,
casings, and the like.
[0035] As a result of the compression of the outside wall of the
pipe, a radial compression force is also exerted on the sealing
ring 17, particularly on its outside wall 19, which tends to be
flattened. Since the material of which the sealing ring 17 is made
is substantially incompressible, the fact that the annular recess
20 formed in the coupling element 13 is wider than the sealing ring
17 housed therein allows the latter to expand longitudinally within
the recess. The resilience of the sealing ring 17 tends to keep its
outside wall 19 in close contact with the inside wall of the
flexible pipe. Any temporary or permanent reduction of the
compression force exerted by the pipe on the sealing ring 17 due,
for example, to use in difficult conditions, to temperature swings,
or to plastic yielding of the clamping collar, does not cause the
formation of a gap between the inside wall of the pipe and the
outside wall of the sealing ring 17, owing to the resilient
recovery of the latter, at least within a wide range of values, the
recovery depending upon the overall dimensional characteristics of
the sealing ring, upon the resilience of the material, and upon the
compression force initially exerted during assembly.
[0036] Naturally, the principle of the invention remaining the
same, the forms of embodiment and details of construction may be
varied widely with respect to those described and illustrated,
without thereby departing from the scope of the present
invention.
* * * * *