ZA200504204B

ZA200504204B - Connecting device for a pipe or similar

Info

Publication number: ZA200504204B
Application number: ZA200504204A
Authority: ZA
Inventors: Zdravko Paluncic
Original assignee: Lincoln Gmbh & Co Kg
Priority date: 2003-06-23
Filing date: 2005-05-24
Publication date: 2006-04-26
Also published as: ES2303637T3; DE20309922U1

Description

Connecting device for a pipe or similar

The invention relates to a connecting device for a pipe or similar fluid conduit, having a coupling member and > a clamping collar which can be inserted into an essentially cylindrical recess of the coupling member into an axially inner initial position and into which, e.g. after the insertion into the recess, an end of the : pipe to be connected can be pushed, e.g. up to a frontal stop of the coupling member, the clamping collar, at its inner end, having at least one radially displaceable locking tongue which, when the pipe and thus the clamping collar are pushed back in the direction of the recess inlet right into an axially outer locking position, e.g. under the pressure building up in the pipe coupling, can be pressed radially inward and with its inside in engagement with the outer wall surface of the pipe by interaction of the outside of the locking tongue with a first slope, falling away radially in the direction of the recess inlet, of the inner wall surface of the coupling member. In this way, a push-in coupling between the pipe or similar fluid conduit can be produced and also released again quickly and simply.

Such a commercially available connecting device is shown in section in fig. 1. In order to produce the tightness between connecting devices, an O-ring seal is provided in the recess of the coupling member at the front face of the inner end of the clamping collar between the outer wall surface of the pipe and the inner wall surface of the coupling member. To release the push-in connection, the clamping collar, e.g. by means of an external flange, can be pushed from the axially outer locking position shown in fig. 1 further into the recess of the coupling member right into its axially inner initial position, as a result of which the locking tongues of the clamping collar, on account of the interaction with the sealing ring and if need be

- 2 = the inherent restoring force, spread out from their position pressed radially inward and can release the pipe end again. It has been shown that, on the one hand, moisture and dirt can penetrate from outside into the gaps between pipe end and clamping collar and also between clamping collar and coupling member, a factor which makes it more difficult to release the push-in connection, and, on the other hand, scratches and damage of that kind are produced in the outer wall surface of the pipe end when the push-in connection is being made and released, as a result of which leakages are produced under the fluid pressure prevailing in the connecting device. In the light of these problems which occur in practice, it was obvious to additionally seal off firstly the pipe end relative to the clamping collar and secondly the clamping collar relative to the coupling member adjacent to the recess inlet, as has also been proposed in EP 1 143 185 Al by means of two

O-ring seals, of which one is provided between clamping collar and inner wall surface of the coupling member and one is provided between clamping collar and outer wall surface of the pipe.

However, a problem is still the reliable spreading of the locking tongues when the clamping collar is being pushed in from the locking position shown in fig. 1, because, on the one hand, the flexibility of the sealing ring which is present at the front face of the clamping collar, and which is aging, and, on the other hand, if the spring elasticity is too low, the inherent restoring force of the spring tongues do not ensure an adequate spreading force.

The object of the present invention is therefore to design a connecting device of the type mentioned at the beginning in such a way that simple means ensure that the push-in connection is made and also released again in a reliable manner.

This object is achieved, for example, according to the invention essentially in that the coupling member, at the front face of the clamping collar, has a second slope which falls away radially in the direction of the recess inlet and which, when the clamping collar is pushed from the axially outer locking position into the axially inner initial position, interacts as abutting slope with the frontal end of the at least one locking tongue in order to spread the latter radially. - 10

According to the invention, metal surfaces therefore act mechanically on one another during the spreading operation, and these metal surfaces determine the spreading operation in a safe and reliable manner. It has surprisingly been found that the O-ring seal at the front face of the clamping collar, this O-ring seal being considered necessary according to the prior art according to fig. 1 and according to EP 1 141 185 Al, can be dispensed with, thereby also saving this component in order to improve the operability of the connecting device according to the invention.

The spreading of the locking tongues for the purpose of releasing the push-in connection can be improved even further by the frontal end of the at least one locking tongue having a tongue slope acting in the same direction and interacting with the second slope of the coupling member.

In the event of an additional seal being necessary, the clamping collar can be sealed off adjacent to the recess inlet of the coupling member relative to the inner wall surface of the coupling member and/or the outer wall surface of the pipe, e.g. by means of two O- ring seals.

Furthermore, for the purpose of reliable locking, it can be advantageous for the at least one locking tongue to be provided with a sharp edge on its side facing the outer wall surface of the pipe.

In a simple configuration of the coupling piece, the first slope is formed by an annular bead which runs around the inner wall surface of the coupling member.

It is especially advantageous for reliable locking and sealing if two or more locking tongues are arranged in a uniformly distributed manner over the circumference of the clamping collar.

In order to be able to press the clamping collar in a simpler manner from the axially outer locking position into the axially inner initial position in the direction of the recess interior, the clamping collar is expediently provided with a circumferential flange at its outer end.

Independently of the solution idea described above, but also together with this solution idea, provision may be made in the case of a connecting device of the type mentioned at the beginning, that is to say of the known type, for the clamping collar to be subdivided into an inner functional section having the at least one locking tongue, which is spread radially outward when said functional section is pushed from the axially outer locking position into the axially inner initial position for releasing the pipe, and into an outer actuating section, a seal, designed as an O-ring seal for example, being arranged between the front faces, facing one another, of functional section and actuating section, this seal providing for sealing radially on the outside relative to the inner wall surface of the coupling member and radially on the inside relative to the outer wall surface of the pipe.

As a result, the problem existing in the case of the connecting device according to EP 1 143 185 Al is solved, so that, in addition to the seal lying at the front face in front of the clamping collar, two further

O-ring seals are required for sealing the coupling interior axially on the outside.

With the present proposal of the invention, a special simplification of the construction is achieved, which in particular comes into effect when the seal arranged at the front face of the clamping collar is also dispensed with and the spreading is effected by means of metal surfaces acting on one another.

So that the actuating section is held in the recess of the coupling member, the former, at its axially inner end, can have at least one radially displaceable latching tongue which, with a projection which points radially outward, latches in place in a groove in the inner wall surface of the coupling member, this groove being open radially inward and being designed, for example, as circumferential groove.

In this case, the circumferential groove preferably has a width which permits an axial displacement of the actuating section to such an extent that the functional section can be displaced back and forth between its axially inner initial position and its axially outer locking position.

For reliable seating of the actuating section in the recess of the coupling member, two or more latching tongues are advantageously arranged in a uniformly distributed manner over the circumference of the actuating section.

Furthermore, within the scope of this inventive idea, it is proposed to produce the functional section from metal and the actuating section from an elastically resilient material, such as plastic, so that the requisite spring elasticity can be imparted to the latching tongues. In this embodiment of the invention, the circumferential flange can be provided on the actuating section, so that a simple displacement of the actuating section via O-ring seal and locking section is possible the clamping collar from the axially outer locking position into the axially inner initial position (release position).

Further aims, features and advantages and possible applications follow from the description below of exemplary embodiments with reference to the drawing. In this case, all the features described and/or illustrated form the subject matter of the invention on their own or in any desired combination, also irrespective of their composition in individual claims or of what the individual claims refer back to.

In the drawing: fig. 1 shows a longitudinal section of a connecting device which belongs to the prior art and on which the invention is based, fig. 2 shows, in a partly sectioned view, an exemplary embodiment of a connecting device which demonstrates the invention, and fig. 3 shows an illustration corresponding to fig. 2 for another approach to solving the invention.

The invention is explained in more detail in its various aspects below with reference to the connecting devices shown in figs 2 and 3. It may first be mentioned that, in fig. 1, the same reference numerals are used for corresponding parts of the connecting device known from the prior art.

The connecting device according to fig. 2 serves for the push-in connection of a pipe 4 or a similar fluid

- 7 = conduit to a preferably metallic coupling member 1 in such a way that a fluid, that is to say a gaseous or liquid medium, can be passed through the connecting device without leakage occurring. The coupling member 1 has an essentially cylindrical recess 3 which extends up to an inner shoulder which serves as a stop 5 for the end of the pipe 4 and adjoining which is a passage section 22 for the fluid to pass through. In this case, the passage section 22 passes through a connecting piece 23 designed, for example, as a threaded connecting piece.

Furthermore, the connecting device has a likewise preferably metallic clamping collar 2, which can be inserted into the recess 3 from the recess inlet 7. In a uniformly distributed manner over its circumference at its axially inner end, the clamping collar 2 has locking tongues 6 which, if need be, are elastic and are separated from one another, for example, by axially parallel slots (not visible) and which, when being pushed in with their widened frontal ends 13, while being deflected radially inward in a flexible manner, can be pushed past an annular bead 21 formed on the inner wall surface 10 of the coupling member until the widened frontal ends 13 come to lie in a widened portion behind an encircling slope 9 falling away radially in the direction of the recess inlet 7. Thus the coupling member 1 and clamping collar 2 form a unit which can be released only by the application of force.

The end of the pipe 4 can then be pushed into the cylindrical recess of the clamping collar 2 up to the stop 5 of the coupling member 1. During the build-up of fluid pressure in the connecting device, the end of the pipe 4 is pushed slightly out of the axially inner initial position at the stop 5 in the direction of the recess inlet 7 into an axially outer locking position (shown in fig. 2) in which there is a gap 24 between the front face of the end of the pipe 4 and the stop 5.

In the process, the pipe 4 takes the clamping collar 2 with it, as a result of which the outside 8 of the widened frontal ends 13 of the locking tongues 6, while interacting with the first slope 9, are pressed radially inward and thus fix the end of the pipe 4. For this purpose, the locking tongues 6 have a sharp edge 16 on their inside facing the outer wall surface 11 of the pipe 4.

As can be seen from fig. 2, the coupling member 1 in this exemplary embodiment, at the front face of the clamping collar 2, has an encircling second slope 12 which falls away radially in the direction of the recess inlet 7 and which, when the clamping collar is being pushed from the axially outer locking position shown in fig. 2 into the axially inner initial position originally assumed, interacts as abutting slope with the frontal end 13 of the locking tongues 6 in order to spread the locking tongues 6. This special configuration of the invention is used for the simple release of the push-in connection. Furthermore, fig. 2 shows that, in order to ensure the functioning, the widened frontal ends 13 of the locking tongues 6 each have a tongue slope 17 acting in the same direction and interacting with the second encircling slope 12. It can be seen when compared with fig. 1 that the frontal sealing ring 20 provided according to the prior art is dispensed with.

On the other hand, for the inlet-side sealing, the clamping collar 2 can be sealed off adjacent to the recess inlet 7 of the coupling member 2 relative to the inner wall surface 10 of the coupling member 1 and/or the outer wall surface 11 of the pipe 4, e.g. by means of respective O-ring seals 14, 15. As a result, penetration of moisture and dirt from outside and escape of fluid from the connecting device to the outside are additionally avoided.

- 9g -

A circumferential flange 18 provided on the outer end of the clamping collar 2 makes it easier to push the clamping collar 2 into the recess 3 from the axially outer locking position shown in fig. 2 inward into the axially inner initial position, in which the end of the pipe 4 is released again from the locking tongues 6.

The connecting device shown in fig. 3 pursues a further inventive idea which is separate from the inventive - 10 idea described hitherto but which can also be applied together with the latter. This is because, in the connecting device shown in fig. 3, the clamping collar 2 is split into two sections axially separate from one another, to be precise into an axially inner functional section 2A and an axially outer actuating section 2B.

In this case, the functional section with the locking tongues 6 performs the locking function and release function, whereas the actuating section 2B serves to axially displace both sections 2A, 2B from the axially outer locking position shown in fig. 3 into the axially inner initial position, in which the pipe 4 is released again from the locking tongues 6. Arranged between the front faces, facing one another, of functional section 2A and actuating section 2B is a circumferential seal which is designed as an O-ring seal 25 and provides for sealing radially on the outside relative to the inner wall surface 10 of the coupling member 1 and radially on the inside relative to the outer wall surface 11 of the pipe 4. The O-ring seal 25 thus lies relatively close to the recess inlet 7 and axially outside the possible scratches which may arise at sharp edges 16 of the locking tongues 6 in the outer wall surface of the pipe 4. The sealing against penetration of moisture and dirt, on the one hand, and against leakages of the fluid to the outside is thus reliably ensured, although only a single O-ring seal 25 is required.

In a uniformly distributed manner over the circumference at its axially inner end, the actuating section 2B has radially displaceable latching tongues 26 which are separated from one another by axial slots 27. The preferably elastic latching tongues 26, with a projection 28 which points radially outward, can latch in place in a circumferential groove 29, open inward, in the inner wall surface 10 of the coupling member 1.

In this case, the circumferential groove 29 has a width which permits an axial displacement of the actuating section 2B to such an extent that the functional section 2A can be displaced between its axially inner initial position and its axially outer locking position, and vice versa.

In this embodiment, the functional section 2A may be made of metal and the actuating section 2B may be made of an elastically resilient material, such as plastic.

The metallic design of the functional section 2A ensures the reliable locking and release function of the latching tongues 6, whereas the actuating section 2B serves merely for the actuating function and cannot be lost. As shown in fig. 3, the circumferential flange 18 in this case is provided on the actuating section 2B.

List of designations 1 Coupling member 2 Clamping collar 2A Functional section 2B Actuating section 3 Recess 4 Pipe 5 Stop © Locking tongue (s) 7 Recess inlet 8 Outside 9 First slope 10 Inner wall surface of the coupling member 1 11 Outer wall surface of the pipe 4 12 Second slope 13 Frontal end 14 Outer O-ring seal 15 Inner O-ring seal 16 Edge 17 Tongue slope 18 Circumferential flange 19 O-ring seal 20 Sealing ring 21 Annular bead 22 Edge section 23 Connecting piece 24 Gap 25 O-ring seal 26 Latching tongue (s) 27 Axial slots 28 Projection 29 Circumferential groove

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Claims

Patent claims

1. A connecting device for a pipe or similar fluid conduit, having a coupling member and a clamping collar which can be inserted into an essentially cylindrical recess of the coupling member into an axially inner initial position for receiving the end of a pipe, the clamping collar, at its inner end, having at least one radially displaceable locking tongue which can be pressed radially inward and with its innerside in engagement with the outer wall surface of the pipe by interaction of the outerside of the locking tongue with a first slope, tapered radially in the direction of the recess inlet, of the inner wall surface of the coupling member, characterized in that the coupling member, at the front face of the clamping collar , has a second slope which tapers radially in the direction of the recess inlet and which, when the clamping collar is pushed from the axially outer locking position into the axially inner initial position, interacts as an abutting slope with the frontal end of the at least one locking tongue in order to spread the latter radially outward.

2. The connecting device as claimed in claim 1, characterized in that the frontal end of the at least one locking tongue has a tongue slope acting in the same direction and interacting with the second slope of the coupling member.

3. The connecting device as claimed in claim 1 or 2, characterized in that the clamping collar is sealed off adjacent to the recess inlet of the coupling member relative to the inner wall surface of the coupling member and/or the outer wall surface of the pipe.

4. The connecting device as claimed in one of claims 1 to 3, characterized in that the at least one locking tongue is provided with a sharp edge on its side facing the outer wall surface of the pipe.

5. The connecting device as claimed in one of the preceding claims, characterized in that the first slope is formed by an annular bead which runs around the inner wall surface of the coupling member.

6. The connecting device as claimed in one of the preceding claims, characterized in that two or more locking tongues are arranged in a uniformly distributed manner over the circumference of the clamping collar.

7. The connecting device as claimed in one of the preceding claims, characterized in that the clamping collar is provided with a circumferential flange at its outer end.

8. The connecting device as claimed in the preamble of claim 1 or as claimed in one of claims 1 to 7, characterized in that the clamping collar is subdivided into an axially inner functional section having the at least one locking tongue, which is spread radially outward when said functional section is pushed from the axially outer locking position into the axially inner initial position, and into an axially outer actuating section, and in that a seal, designed as an O-ring seal, this seal providing for sealing radially on the outside relative to the inner wall surface of the coupling member and radially on the inside relative to the outer wall surface of the pipe.

9. The connecting device as claimed in claim 8, characterized in that, at its axially inner end, the actuating section has at least one radially displaceable latching tongue which, with a projection which 1s directed outwardly, latches in place in a groove in the inner wall surface of the coupling member.

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10. The connecting device as claimed in claim 9, characterized in that the circumferential groove has a width which permits an axial displacement of the actuating section to such an extent that the functional section can be displaced back and forth between its axially inner initial position and its axially outer locking position.

11. The connecting device as claimed in one of claims 8 to 10, characterized in that two or more latching tongues are arranged in a uniformly distributed manner over the circumference of the actuating section.

12. The connecting device as claimed in one of claims 8 to 11, characterized in that the functional section is made of metal and the actuating section is made of an elastically resilient material, such as plastic.

13. The connecting device as claimed in one of claims 8 to 12, characterized in that the circumferential flange is provided on the actuating section.

14. A connecting device for a fluid conduit comprising a coupling member and a clamping collar, the coupling member having a cylindrical recess including a frontal stop and shaped to receive and locate the clamping collar which has at least one radially displaceable locking tongue at its operatively inner end movable to engage the outer wall surface of a fluid conduit inserted into the clamping collar by the interaction of a shaped outer wall of the tongue with a sloping wall in the recess characterized in that the tongue can be spread outwardly by its inner end engaging a tapered surface on the frontal stop.

15. A connecting device for a pipe substantially as described with reference to Figs 2 or 3 of the drawing.