Note: Descriptions are shown in the official language in which they were submitted.
CA 02371191 2001-12-04
Plug-in Coupling
The invention relates to a plug-in coupling.
European Patent Application EP 587 131 Al describes such a plug-in coupling,
which is
embodied as a double coupling and comprises a basic body and a holding device
or locking
device for the corresponding ends of the pipes to be connected, which can be
inserted into
the coupling body. The holding device comprises a locking ring, which has a
locking cone on
the outside and at least one locking rib on the inside, which can engage with
the
corresponding pipe end. By means of a union nut, which can be screwed onto the
coupling
body, an opposite cone can be locked in position using said locking ring.
Furthermore, along
the interior of the coupling body, a sealing ring is provided, which fits
tightly against the
exterior surface of the inserted pipe end. The pipe end must have sufficient
rigidity, so that
it does not yield toward the interior due to the radial locking force
components, which would
jeopardize the axial fixation of the pipe end within the plug-in coupling.
When the connection
is established, care must be taken that the pipe end is inserted far enough
into the coupling
body, so that the locking ring as well as the sealing ring can perform their
function. If the pipe
end is incompletely inserted into the plug-in coupling, there is a risk that
the connection is
either not being made at all or is being made incorrectly. Furthermore,
especially in pressure
pipes, there is the problem that the pipe end may be partially moved out of
the plug-in
coupling due to relative movements of the pipe end in relation to the plug-in
coupling, so that
the required seal and/or axial fixation can no longer be guaranteed.
Based thereon, the object of the invention is further to develop the plug-in
coupling of the
cited type, so that the connection can be made with at least one pipe end with
little effort and
high functional reliability. The plug-in coupling should permit functionally
suitable handling
during mounting and should exclude any risk of mounting errors. The plug-in
coupling should
be equally suitable for pipes of different materials, such as plastic or metal
or a composite
thereof (composite pipes made of plastic with a metal interlayer) and should
provide a secure
connection over many years even for comparatively soft materials, particularly
polyethylene,
for example. Furthermore, the plug-in coupling should be suitable especially
for plumbing
applications, particularly for hot water and cold water installations. It
should reliably absorb
any changes in the material, especially with respect to dimensions or
rigidity, resulting
particularly from temperature changes of the flowing medium.
CA 02371191 2001-12-04
2
The present invention provides plug-in coupling comprising a basic body, a
sealing ring a
locking ring, and an annular body, which can be connected with the basic body,
wherein a
pipe end can be locked into position by means of the locking ring,
characterized in that the
pipe end can be inserted into an axial annular gap between the basic body and
the annular
body, that the sealing ring fits tightly against the interior surface of the
pipe end and that the
annular gap furthermore accommodates the locking ring, which fits under
initial stress
against the locking surface of the annular body on the one hand and against
the exterior
surface of the inserted pipe end on the other hand.
The plug-in coupling according to the invention is characterized by a
functionally reliable
design and little complexity in production and assembly. The basic body, which
partly
engages with the interior of the pipe end, guarantees secure radial support of
the pipe end,
so that the locking forces of the holding means are reliably absorbed and
transmitted even
under changing operating conditions. An annular body or cap, which radially
surrounds the
exterior of the pipe end, is coupled together with the basic body. The pipe
end is locked into
position in an annular space between the basic body and the cap. The interior
surface of the
annular body or the cap is preferably conical. The locking ring, which is
coupled on either side
in a non-positive and/or a positive fit with both the interior surface of the
annular body and the
exterior surface of the pipe, is arranged between said interior surface of the
annular body and
the exterior surface of the pipe end. The sealing element is preferably
arranged on the
portion of the basic body that engages with the pipe end and fits tightly
against the interior
surface of the pipe end. The locking or holding ring has at least one holding
claw each
radially on the inside and radially on the outside, which claws are
respectively pressed into
the exterior surface of the pipe end and into the interior surface of the
annular body.
In a special embodiment of the invention, the locking ring comprises at least
one additional
integrally formed clamping element, which is used to produce initial stress on
the pipe in the
mounted state. This improves and/or accelerates claw fixation of the pipe. The
cap
comprises at least one projection and/or annular collar associated with the
locking ring and/or
the clamping element to support the clamping element or the locking ring. The
clamping
element is seated against the annular collar such that the locking ring
preferably contacts the
corresponding locking surface of the cap under initial stress. When the pipe
end is inserted
into the plug-in coupling, the locking ring can yield in axial direction
against the prestressing
force of the clamping element, while the insertion resistance preferably
remains essentially
unchanged. After complete insertion of the pipe end, the locking ring is
pressed against the
especially conical locking surface of the cap or the annular body by means of
the clamping
element, so that the pipe end is quickly and securely fixed in the plug-in
coupling.
CA 02371191 2001-12-04
3
Manufacturing tolerances of the plug-in coupling, particularly of the annular
body and the
locking ring, are thus compensated just as reliably as manufacturing
tolerances of the pipe
end and particularly its outside diameter. There is no longer any risk that
the locking ring
mounted inside the cap will already be radially deformed to such an extent
that the pipe end
can be inserted into the plug-in coupling only by overcoming a large insertion
resistance.
Advantageously, several, preferably three, such elastic clamping elements are
provided.
They are connected with the locking ring along one of its axial end faces,
particularly via short
ribs oriented in substantially axial direction, and form an integral unit with
the locking ring. The
cap or the annular body preferably comprises radially inwardly pointing
projections that can
engage with the clamping element to produce radial prestressing and reliable
claw fixation
and bracing with the pipe end, which is inserted into the plug-in coupling.
Advantageously, the cap or the annular body is provided with at least one
inspection window,
which is designed particularly in the form of a radial port or opening or an
at least partially
transparent area. This makes it possible to check at any time by visual
inspection whether
the pipe end is properly inserted into the plug-in coupling, particularly up
to a predefined limit
stop. This visual inspection is simple to perform either during or after
assembly, including
after prolonged operation, so that any impending detachment of the connection
can be
detected at any time and suitably corrected. The cap is preferably made of a
completely
transparent material; production problems are avoided due to the one-piece
design.
Furthermore, the cap can have at least one transparent window for visual
inspection. In this
case, the entire cap is advantageously made of a transparent material, which
is dyed or
provided with a coat of paint on the inside of the cap, except for the
inspection window or
windows. In addition, or as an alternative, in the context of the invention,
the cap can have
at least one radially continuous opening or port to permit verification from
the outside at any
time that the pipe end has been fully and properly inserted into the plug-in
coupling. In case
of improper assembly, the area of the face of the pipe end is not located
radially inside the
area of the inspection window or said opening, so that an improper connection
can be readily
detected.
In a further embodiment of the invention, the sealing ring and the basic body
comprise
holding elements, annular grooves or the like that correspond and engage with
one another
and/or adjoin one another to fix the sealing ring axially on the basic body.
As a result, as the
pipe end is inserted into the plug-in coupling, the sealing ring maintains its
predefined position
and any unacceptable pushing of the sealing ring into the plug-in coupling or
damage to the
CA 02371191 2008-01-17
4
sealing ring is avoided. The sealing ring advantageously contains at least one
sealing bead or a
sealing lip, which can be brought into contact with the interior surface of
the associated pipe end.
In this case the basic body is also arranged within the pipe end. Also within
the scope of the
invention, the sealing ring can be arranged or embodied in such a way that it
can be brought into
contact with the exterior surface of the pipe end. In this case, the basic
body radially surrounds
the exterior of the pipe end in the manner of a sleeve. By means of suitable
coupling elements,
such as locking rings or clamping rings, particularly provided with holding
claws, the pipe end is
fixed in the plug-in coupling in a non-positive and/or positive fit.
Particularly advantageously, the
sealing ring is arranged in an annular groove provided in the exterior surface
of the basic body.
Between the annular groove and the free end of the basic body, the basic body
contains a ring by
means of which the sealing ring is secured against any unintended dislodging
or shifting as the
pipe end is inserted. The ring is a functionally reliable protection against
dislodging of the sealing
ring, which fits against the interior surface of the pipe end to form a seal
when the pipe end is
further inserted. Particularly advantageously, the sealing ring is flat, i.e.,
its radial thickness is
substantially smaller than its axial length. The radial wall thickness of the
portion of the basic body
that together with said sealing ring lies inside the pipe end can thus be
designed comparatively
small, which ultimately results in an optimized inside diameter of the basic
body and minimizes the
reduction of area.
It should be noted that the plug-in coupling according to the invention can
form part of a fitting for
connecting two or more pipes, e.g., in the form of an elbow, a wall disk or a
T-piece. It can also
form a component of the housing of a valve, a transition piece between pipes
made of different
materials, or the like. When made as a fitting or a double coupling to connect
two or more pipes,
the pipe axes can be positioned at any angle in relation to each other. It
should also be expressly
noted that the plug-in coupling is particularly suitable for pipes made of
different materials and/or
with different material properties.
In a further aspect, there is provided a plug-in coupling comprising a base
body, an annular body
for connection with said base body, said base body and said annular body
forming between them
an annular gap for receiving an inserted pipe end, a sealing ring, and a
locking ring for locking an
inserted pipe end into position, wherein the sealing ring fits tightly against
the interior surface of
the pipe end, and the annular gap accommodates the locking ring, which fits
under initial stress
against a locking surface of the annular body and against the exterior surface
of the inserted pipe
end, the locking ring has at least one additional clamping element which lies
against an interior
surface of the annular body, and the clamping element is arranged in the area
of an axial end face
of the locking ring.
CA 02371191 2008-02-06
4a
Special embodiments and further developments of the invention are set forth in
the dependent
claims as well as in the further description.
The invention will now be described in greater detail with the aid of special
exemplary
embodiments depicted in the drawing, which shall not, however, be construed as
a limitation.
In the drawings
Fig. 1 is a longitudinal section through the plug-in coupling for connecting
two pipe ends,
CA 02371191 2001-12-04
Fig. 2 is an enlarged detail A according to Figure 1,
Fig. 3 is a longitudinal section through another special embodiment of the
plug-in
coupling,
Fig. 4 is a longitudinal section through the annular body and the locking ring
of an
embodiment similar to that shown in Fig. 3,
Fig. 5 is a section through another exemplary embodiment of the basic body,
Fig. 6 is an enlarged detail VI according to Fig. 5,
Fig. 7 is a view of a plug-in coupling embodied as a T-type connector,
Fig. 8 is a section through a portion of the plug-in coupling together with
the inserted
pipe end,
Fig. 9, 10 are longitudinal sections of another special exemplary embodiment
of the plug-in
coupling,
Fig. 11 is an enlarged view of the locking ring according to Fig. 9,
Fig. 12 is a perspective view of the locking ring, and
Fig. 13 is an enlarged view of the sealing ring according to Fig. 9.
The plug-in coupling according to Fig. 1 is designed as a double coupling and
is symmetrical
to the center axis 2 and serves to connect two pipe ends 4, 5. The following
description
applies correspondingly to the two parts of the plug-in coupling, which are
symmetrical to
each other. The plug-in coupling comprises a basic body 6, which is partially
inserted,
respectively, into the two pipe ends 4, 5. The inner end areas 8 of the basic
body 6 are
preferably formed as conical expansions oriented radially outwardly in the
direction of the
interior surfaces 10, 11 of the corresponding pipe ends 4, 5. In addition, a
sealing ring 12,
arranged particularly in an annular groove of the exterior surface of the
basic body 6, fits
CA 02371191 2001-12-04
6
against the corresponding interior surface 10, 11 so as to form a seal. The
basic body 6
further comprises a first radially outwardly directed rib 14 as a limit stop
for the face of the
pipe end 4 or 5 which is inserted into the plug-in coupling. This rib 14 is
preferably formed as
a circumferential closed ring relative to the longitudinal axis 16, but can
also be divided into
a plurality of segments.
Furthermore, a cap or an annular body 18 is provided, which surrounds the
respective pipe
end 4, 5 along the exterior. On the interior, the annular body 18 comprises a
preferably
conical locking surface 20, whose inside diameter decreases in the direction
pointing away
from the basic body or toward the free end 22 of the corresponding annular
body 18. The cap
or annular body 18 further comprises a connecting element 24, which engages
with the first
rib 14. The rib 14 thus performs a dual function, acting as a limit stop for
the pipe end and
fixing the annular body 18. Advantageously, the connecting element 24
comprises an annular
groove 26 with which the first rib 14 engages with its radially outer edge 28.
The annular body
18, particularly its connecting element 24, overlaps the face of the inserted
pipe end in axial
direction away from the free end of the basic body 6 and, furthermore,
especially annularly
overlaps the outer edge of the first rib 14. In addition, it can preferably be
divided into a
plurality of segments. At least the connecting element 24 can be elastically
deformed in such
a way that for assembly it can be pushed over the outer rim of the first rib
14 to assume the
depicted locked position with respect to the basic body 6. Particularly
advantageously, the
annular body 18 and the basic body 6 are assembled or connected at the factory
in such a
way that prior to insertion of the pipe end, an annular gap 27 is present
between the basic
body 6 lying on the inside and the annular body 18 lying on the outside. When
the plug-in
coupling is connected with the pipe end 4, 5, the pipe end can be axially
pushed into this gap.
In the embodiment shown, the annular body 18 is permanently and non-detachably
connected with the basic body 6 by means of the connecting elements 24.
Alternatively and
within the scope of the invention, this connection can be detachable, in which
case the
connecting elements are provided particularly with an internal thread, which
engages with a
corresponding external thread of the basic body. Also within the scope of the
invention, other
connections, e.g., bayonet-type connections, may be provided.
The annular body 18 comprises an inspection window 30 and/or is transparent at
least in the
area of the rib 14 or the limit stop for the pipe end to make visible from the
outside the radially
inner face of the pipe end 4, 5 or the portion adjacent thereto. This permits
visual inspection,
so that a possibly incomplete insertion of the pipe end during assembly or any
subsequent
partial detachment of the pipe end can be readily detected. Advantageously, a
plurality of
CA 02371191 2001-12-04
7
these inspection windows is distributed over the circumference of the annular
body 18,
particularly in the form of radial ports or openings, so that visual
inspection is readily possible
from practically any side. In an alternative embodiment, the entire annular
body 18 is made
of a transparent material, particularly of plastic. The inspection window 30
according to the
invention is provided outside the interior area of the plug-in coupling that
is sealed by means
of the sealing ring. Axially adjacent to the inspection window or windows 30,
away from the
free end of the basic body 6, the inventive connecting element or elements 24
is or are
provided to connect the annular body 18 with the basic body 6. The basic body
furthermore
comprises a second rib 32, which is spaced axially apart from the first rib
14, such that the
annular body 18 with a radially inwardly pointing hook-shaped extension 34
engages with the
annular space 35 between said ribs 14, 32 to fix the annular body 18 on the
basic body 6.
The second radial rib 32 serves as an insertion limit for the annular body 18
when it is
mounted to the basic body 6. In the embodiment as a double coupling depicted
here, there
is an annular groove 36 in the basic body 6 between the two ribs 32, which are
axially spaced
apart. This annular groove 36 can serve as an engaging means, e.g., a hexagon,
for a tool
used to produce the connection with the annular body 18 or the pipe end 4, 5.
As may be seen from the drawing, the annular body 18 at its free end 22 has an
area 38 with
a defined axial length within which the sealing ring 12 is arranged. With this
area 38, the
annular body 18 fits at least approximately against the exterior surface of
the respective
inserted pipe end 4,5. The interior surface of the annular body 18 is
preferably cylindrical in
this area 37 [sic] and thus ensures secure radial support of the pipe end and,
consequently,
a secure seal by means of the radially inwardly located sealing ring 12.
As may be seen in the enlarged detail view according to Fig. 2, a locking ring
40 is arranged
radially between the annular body 18 and the pipe end 5. This locking ring 40
particularly
advantageously comprises a first part 42 and a second annular part 44. The
first cylindrical
part 42 is adjacent to the first rib 14 and advantageously has a cylindrical
interior surface
and/or a cylindrical exterior surface. In the area of the first part 42, the
interior surface 46 of
the annular body 18 is advantageously also substantially cylindrical.
Furthermore, the annular
body 18 has an annular collar 48, partially opposite which an axial end face
of the locking ring
40, or its first part 42, is provided.
The second part 44 is wedge-shaped according to the invention, its thickness
tapering in the
direction toward the free end of the plug-in coupling. As described above, the
locking surface
CA 02371191 2001-12-04
8
20 of the annular body 18 preferably tapers conically. The second part 44
preferably has a
likewise conical exterior surface to fit against said locking surface 20. The
exterior surface
of the second locking ring part 44 and its interior surface intersect at a
first aperture angle 52.
In contrast, the locking surface 20 intersects the exterior surface of the
inserted pipe end 5
at a second aperture angle 54. The locking ring 40 according to the invention
has a radially
inwardly pointing holding or cutting claw 56, which is particularly ring-
shaped and is pressed
into the exterior surface of the pipe end 5. Advantageously, the locking ring
40 furthermore
has at least one radially outwardly pointing second holding claw 58, which is
pressed into the
locking surface 20. Due to their substantially linear engagement with the
exterior surface of
the pipe end 5 and/or the inner locking surface of the annular body 18, the
preferably annular
holding claw or claws 56, 58, ensure high pressure per unit area and
ultimately provide a
secure lock against axial pull-out forces of the pipe end 5 from the plug-in
coupling. Since
said first aperture angle 52 according to the invention is greater than said
second aperture
angle 44, said holding claws 56, 58 are particularly effective. These radially
inwardly or
radially outwardly directed holding claws 56, 58 are simple to produce and
ensure high
pressure per unit area.
Fig. 3 shows a special embodiment of the plug-in coupling according to the
invention, which
can be designed as a double coupling, only half of which is depicted. The
sealing ring 12,
which fits against the interior surface of pipe end to be inserted, is
arranged in the area of the
free end 60 of the basic body 6. The annular body 18 comprises a projection
62, which in
conjunction with a clamping element of the locking ring 40, which will be
further described
below, produces a quick and/or additional prestressing or claw fixation of the
radially inwardly
located pipe end. In other respects, the description of the first embodiment
of the plug-in
coupling applies correspondingly.
Fig. 4, in an axial plane, shows an embodiment of the annular body 18 and the
clamping ring
40, which is slightly modified compared to that depicted in Fig. 3. The
annular body 18
comprises a radially inwardly pointing step or annular collar 63 against which
the elastic
clamping elements 64 of the locking ring 40 are seated. Thus, the clamping 64
elements
press the locking ring 40 in the direction of arrow 65 against the locking
surface 20 of the
annular body 18 with a predefined initial stress. Manufacturing tolerances are
thus
advantageously compensated. The prestressing in the context of the invention
is defined in
such a way that the pipe end can be inserted into the plug-in coupling
virtually without any
increase in the insertion resistance. Without the clamping elements 64, tight
manufacturing
tolerances would have to be met for the annular body and the locking ring as
well as for the
pipe end to be inserted in order to avoid, on the one hand, an excessively
high insertion
CA 02371191 2001-12-04
9
resistance for the pipe end if the inside diameter of the first inner holding
claw 56 were too
small and to ensure, on the other hand, a secure fit and immediate engagement
of the
holding claw 56 with the inserted pipe end. The corresponding clamping element
64 is
integrally connected with the locking ring 40 by means of a short rib 66 in
the area of the axial
end face 68. As may be seen, the axial end face 68 is spaced at a predefined
distance 70
from the annular collar 63. The clamping element or elements 64 is/are
arranged in the axial
area 72 thus defined. As shown, the projections 62 extend into this axial area
72 as well as
into the adjacent interior area 74 of the annular body 18 facing away from the
locking ring.
Said axial area 72 has a larger inside diameter than the interior area 74 of
the annular body
18, which adjoins it via the step or the annular collar 63. It should
furthermore be expressly
noted that the elastic clamping element 64 is arranged axially to the side of
the locking ring
40, which side is opposite the aforementioned first and second part of the
locking ring 40.
The projections 62 advantageously end at a predefined axial distance 76 in
front of the end
face 68, so that a secure axial orientation of the locking ring 40 is
guaranteed and any tilting
or inclining of the locking ring within the annular body 18 is excluded. When
a pipe end is
inserted, the axial distance 76 can approach zero, so that a coaxial alignment
of the locking
ring 40 within the annular body 18 is advantageously ensured.
Figure 5 shows a section through another exemplary embodiment of the basic
body 6, which
is designed as a T-fitting for connecting three pipes. The parts of the basic
body 6 associated
with each pipe conform, so that the further description applies
correspondingly to all three
parts of the fitting. The basic body 6 comprises an outer annular space 35,
which is
advantageously arranged between the two radial, axially spaced ribs or rings
14, 32. These
ribs 14, 32 can be present in the form of rings that are closed across the
circumference or
as a plurality of segments with defined distances therebetween in
circumferential direction.
The annular space 35 is provided to lock in position the cap, not shown, by
means of which
the pipe end can be connected with the basic body 6 and which ends in the area
of the ribs
14, 32. The rib 14 facing the free end 77 of the basic body 6 advantageously
has a smaller
outside diameter than the other rib 32, which is axially spaced further apart
from the end 77.
Furthermore, the exterior surface 78 of the rib 14 that is closest to the free
end 77 is sloped
or flattened in the direction toward the free end 77, so that connecting
means, snap-in
elements or the like of said cap can be readily pushed over the rib 14 to
engage with the
annular groove 26 to fix the cap axially.
CA 02371191 2001-12-04
Fig. 6 shows an enlarged detail V according to Fig. 5. The fitting body 6
comprises a first
annular groove 80 for a sealing ring (not shown). A radially outwardly
pointing profile ring 82
is provided on the bottom 84 of the profile groove 80. This profile ring 82 of
the basic body
6 engages with a corresponding annular groove of the flat sealing ring, which
fixes said
sealing ring securely to the basic body 6. Between the annular groove 80 and
the free end
77, the basic body 6 comprises a radially outwardly pointing ring 86 by means
of which the
sealing ring is secured against shifting or dislodging as the pipe end is
inserted. The ring 86
has a beveled exterior surface 88 sloping toward the free end 77, which
particularly
advantageously serves as an insertion aid and centers the pipe end relative to
the basic
body. In interaction with the ring 86 according to the invention and the
profile ring 82, this
reliably prevents any undesirable shifting of the flat sealing ring as the
pipe end is inserted
into the plug-in coupling. Alternatively, other corresponding profile rings
may also be provided
within the scope of the invention. The bottom 84 of the annular groove 80
preferably has a
predefined axial extension 90 and is advantageously embodied as a cylindrical
surface that
is coaxial to the longitudinal axis 16. The axial extension 90 of the annular
groove 80 is
advantageously much larger than its radial depth.
Fig. 7 depicts the plug-in coupling embodied as a T-unit with the basic body 6
corresponding
to that shown in Fig. 5. As may be seen, the plug-in coupling comprises three
eyes or annular
bodies 18 on the corresponding end of the basic body 6. The annular bodies 18
comprise the
aforementioned inspection windows 30, namely four each, which are uniformly
distributed
across the circumference. The inspection windows 30 are embodied as radial
ports or
openings and according to the invention permit visual inspection of the
corresponding pipe
end, which is inserted into the annular gap between the annular body 18 and
the basic body
6.
Figure 8 shows an axial longitudinal section of a portion of the plug-in
coupling. The pipe end
5 is inserted into the axially extending annular gap 27 between the basic body
6 and the
annular body 18. The sealing ring 12 comprises a radially outwardly pointing
sealing bead
124, which is depicted in its non-compressed state for the sake of simplicity.
In fact, the
sealing bead 124, which fits tightly against the interior surface of the pipe
end 5, is deformed
and/or compressed in such a way that it is located radially inwardly inside
the annular groove
80. The sealing ring 12 according to the invention is a gasket with an axial
length 92 that is
greater by a predefined factor than the radial thickness of the sealing bead
124. As will be
described below, the sealing ring 12 has yielding spaces axially adjacent to
the sealing bead
124 into which the sealing bead 124 is at least partially pressed as the pipe
end is inserted.
In the direction toward the free end 77 of the basic body 6 the sealing ring
12 has a second
CA 02371191 2001-12-04
11
sealing bead 96, which also fits tightly against the interior surface of the
pipe end 5. This
second sealing bead 96 particularly advantageously has a smaller outside
diameter than the
first-mentioned sealing bead 124. The outside diameter of the second sealing
bead 96
provided according to the invention is at least equal to, but advantageously
greater by a
predefined amount than the inside diameter of the pipe end 5. This ensures a
double seal
by means of sealing ring 12 in a particularly advantageous manner, while low
insertion
resistance is nevertheless given due to the different and/or stepped
definition of the
diameters of the two sealing beads 96, 124. According to the invention, the
profile ring 82 is
located in front of sealing bead 96 and/or sealing bead 124 as seen in
insertion direction. The
distance between the profile ring 82 and the free end 77 of the basic body 6
is smaller than
the distance between the sealing bead 96 and/or sealing bead 124 and the free
end 77. As
the pipe end is inserted, its end face first contacts the sealing bead 96,
which is closest to the
free end 77. This provides a particularly advantageous axial fixation of the
sealing ring 12
inside the annular groove 80 of the basic body 6. With further insertion, and
particularly upon
reaching the sealing bead 124, any displacement of the sealing ring 12 out of
the annular
groove 80 is reliably avoided.
Figures 9, 10 show a further embodiment of the plug-in coupling which, similar
to the
embodiment depicted in Fig. 1, is designed as a double coupling and comprises
the basic
body 6 and the two annular bodies or caps 18. The locking rings 40 are
essentially similar in
design to the embodiment shown in Fig. 4, but without the described clamping
elements. The
locking ring 40 comprises the first inner holding claw 56 and the second outer
holding claw
58, which is associated with the conical locking surface 20 or 21 of the cap
18 or 19. The
basic body 6, in front of the free end 77, comprises a substantially
cylindrical area 112 or an
annular groove to receive the sealing ring 114. The sealing ring 114 comprises
a holding
element 100, which overlaps the free end 77 of the basic body. This holding
element 100 is
hook-shaped and comprises a radially inwardly directed contact surface 102
which fits
against the free end 77. Even if friction is comparatively high, the sealing
ring 114 is thereby
prevented from being pulled along during assembly or mounting of the pipe end.
This hook
geometry of the holding element 100 and/or the conically expanded design of
the interior
surface 104 of the sealing ring 114, which is directed away, in particular,
from the free end
of the basic body 6, results in a flow-enhancing embodiment of the inflow
area. The area 112
has a smaller outside diameter than the additional adjacent area 116 toward
the center of the
coupling body. A step 118 is present between said areas. At the free end 77,
the coupling
body 6 has a radially outwardly directed profile part 120, which engages with
a corresponding
CA 02371191 2001-12-04
12
annular groove 122 of the sealing ring 114. In combination with the profile
part 120 engaging
with the annular groove 122 and the holding element 100, the sealing ring 114
is axially fixed
in a functionally reliable manner. Furthermore, the sealing ring 114 has a
radially outwardly
projecting sealing bead or a sealing lip 124 which, after the pipe end has
been inserted, fits
tightly against the interior surface of the pipe end. The cap 18 comprises the
at least one
inspection window 30, which is preferably designed as a radially continuous
opening. This
makes it readily possible during assembly to verify whether the pipe end has
been fully
inserted into the plug-in coupling. Even after assembly, a simple visual
inspection can verify
at any time whether the pipe end is still completely and properly fixed within
the plug-in
coupling.
Fig. 11 is a partial and enlarged view of the locking ring 40 with the
radially inwardly pointing
first holding claw 56. The locking ring is preferably a rolled profile,
particularly made of spring
steel. Within the scope of the invention, the locking ring 40 can also be made
of a different
material, particularly plastic, which is harder and/or tougher than the
material of the pipe end
to be inserted. The inner holding claw 56 is provided at least approximately
within the
transition area between the first part 42 and the second part 44 of the
locking ring 40. Said
first part 42 has a substantially cylindrical exterior surface, whereas the
second part 44 has
a substantially conical exterior surface that tapers toward the second holding
claw 58. The
holding claw 56 has an interior surface 126 directed toward the first part 42,
which preferably
lies in an essentially radial plane. The holding claw 56 furthermore has a
second interior
surface 128 associated with the second part 44. Said two interior surfaces
126, 128 form an
acute angle. This advantageously fixes the inserted pipe in a functionally
reliable manner.
During insertion, the pipe end can easily be pushed over the second angled
interior surface
128. The surfaces of the two outer holding claws 58 are also arranged in such
a way that they
form an acute angle with respect to each other to ensure that they securely
claw into the
associated locking surface of the cap.
Fig. 12 is a perspective view of the locking ring 40 in which the axial gap or
slot 130 may be
readily seen. The slot 130 makes it simple to mount the locking ring 40 inside
the cap.
Fig. 13 is a partial and enlarged view of the sealing ring 112 with the
aforementioned annular
groove 122 with which the above described profile ring of the basic body
engages. The
holding element 100 in this special embodiment of the sealing ring 112 has a
substantially
cylindrical interior surface 132. The diameter 134 of the interior surface 132
is preferably
smaller by a predefined factor than the diameter 136 of the remaining interior
surface 138 of
the sealing ring. The sealing bead or sealing lip 124 has a basically
triangular cross section
CA 02371191 2001-12-04
13
with the radially outward lying tip 140 being rounded. Adjacent to the sealing
bead 124, a
yielding space 142 is provided in whose area the sealing ring has a reduced
wall thickness.
On the other side, the exterior surface 144 of the sealing lip 124 is
advantageously concave.
Thus, the sealing lip 124 can easily yield as the pipe end is being inserted,
so that insertion
resistance is low. At the front end 146 of the sealing ring, the exterior
surface 98 is tapered,
particularly conically tapered, so that the pipe end can be easily inserted
into the plug-in
coupling while being simultaneously centered.
CA 02371191 2001-12-04
14
Reference Numbers
2 center plane
4, 5 pipe end
6 basic body
8 inner end area of 6
10, 11 interior surface of 4, 5
12 sealing ring
14 first rib
16 longitudinal axis
18 annular body / cap
20 locking surface
22 free end of 18
24 connecting element
26 annular groove in 24
27 annular gap
28 edge of 18
30 inspection window
32 second rib
34 radial extension
35 annular space
36 annular groove in 6
38 area in 22
40 locking ring
42 first part of 40
44 second part of 40
46 interior surface of 18
48 annular collar of 18
52 first aperture angle of 44
54 second aperture angle
56 first inner holding claw of 40
58 second outer holding claw of 40
60 free end of 6
62 projection
63 step / annular collar in 19
64 clamping element
CA 02371191 2001-12-04
65 arrow
66 rib
68 end face to 40
70 spacing
72 axial area
74 interior area
76 axial spacing
77 free end of 6
78 exterior surface of 14
80 annular groove
82 profile ring
84 bottom of 80
86 ring
88 exterior surface of 86
90 extension
92 axial length of 12
94 radial thickness of 12 / 124
96 second sealing bead
98 exterior surface
100 holding elements
102 contact surface
104 interior surface of 100
112 cylindrical area of 6
114 sealing ring
116 additional area of 6
118 step
120 profile part
122 annular groove
124 sealing bead / sealing lip
126, 128 interior surface of 56
130 gap / slot
132 interior surface of 100
134 inside diameter of 100
136 inside diameter of 138
138 remaining interior surface
CA 02371191 2001-12-04
16
140 tip of 124
142 yielding space
144 exterior surface
146 front end of 12
