DE20003983U1 - Pipe connection connection - Google Patents

Description

Dipl.-Chem. EL FRITZ 00/031

Dr. Dipl.-Phys. R. BASFELD 29.02.2000/HZ/AB

Dipl.-Phys. E. HARAZIM Patent attorneys M. HOFFMANN Attorney Mühlenberg 74 59759 Arnsberg

company

WIRA vehicle and

Machine Parts GmbH

Old Paper Mill Hammering

51688 Wipperfürth

"Pipe connection"

The present invention relates to a pipe connection for plug-in connection of a pipe end, in particular made of plastic.

The connection housing is formed by a pipe connection piece with a through hole, which has an insertion opening for the pipe end on its front connection side and is provided with an external thread on its rear screw-in side. Seals, a cutting ring and a support sleeve are housed inside the connection housing.

Such pipe connection connections are plug-in connections that enable a particularly simple and yet reliable connection of pipes, especially plastic pipes, to valve or distributor housings as well as pressure vessels and the like. To connect, the pipe end is simply pushed into the hole from the front until it stops. The support ring arranged in it has a tubular sleeve part arranged coaxially in the housing hole, which extends forwards into the insertion opening. The outer diameter of this sleeve part corresponds to the inner diameter of the inserted pipe end, so that this is pushed onto the sleeve part when inserted.

An annular surface on the support sleeve, which projects radially outwards from the sleeve part, forms an insertion depth limit, i.e. a longitudinal stop when inserting the pipe end. To ensure that the support sleeve is not pushed backwards out of the pipe connection piece, it is fixed axially in the bore. In the insertion area of the pipe end, there is also a slotted cutting ring inside the bore. This is tapered towards the front on the outside and is arranged so that it can move in the longitudinal direction in a corresponding inner cone section of the bore. On its inside, the cutting ring is provided with barb-like teeth or ring projections, which allow the pipe end to be inserted, but which catch on it when it is pulled back.

outer surface so that the cutting ring with its clamping cone is pulled forwards into the inner cone. This compresses the slotted ring radially onto the pipe; the pipe is clamped more tightly between the cutting ring and the sleeve part, the greater the tensile load exerted from the outside.

The seal arranged in the front area of the bore, for example an O-ring, also seals against the outside of the pipe under elastic deformation and serves as an external secondary seal.

The pipe connection piece is screwed directly into a container wall or a valve housing with its external thread cut into the rear area. Sealing is achieved by means of a ring seal that is inserted between the relevant surface and a sealing collar that projects outwards.

0 Such a pipe connection is known, for example, from DE 33 25 350 C2. The resulting construction does indeed enable the simple assembly of a plastic pipe on a screw-in pipe socket as explained above. However, the problem with this is that the support sleeve, referred to therein as the support tube, is attached to the front of the screw-in shaft. In order to fix the stop ring of the support sleeve in place as required, it is proposed that a narrow ring-shaped retaining web be formed on the screw-in end of the thread, 0 whereby the stop ring with protruding axial ring webs is pressed onto the screw-in end together with the support tube.

If necessary, the support sleeve can be made in one piece with the stop ring. However, this does not change the fact that in the known embodiment this component is simply pressed axially into the bore under elastic tension. This type of friction-locked mounting

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has the disadvantage that the tightest dimensional tolerances must be maintained, otherwise either excessive tensions will occur when pressing in or the stop ring will come loose and fall out when a pipe end is inserted. However, to dismantle the plug connection, the stop ring and the support pipe should be easy to pull out after unscrewing the connection piece. Such easy assembly naturally requires a sufficiently smooth fit. However, this contradicts the idea that the stop ring should fit as securely as possible when a pipe end is inserted.

A further disadvantage is that in the known design the stop ring always protrudes beyond the screw-in end of the screw-in shaft. The stop ring must rest on the end face so that it is not accidentally pressed in too far, which would press the cutting ring into the clamping cone and could endanger the usability of the pipe connection piece.

In view of the problems explained above with pipe connectors according to the prior art, the object of the present invention is to provide a pipe connection with improved functionality, in which the entire support sleeve does not protrude beyond the pipe connection piece on the screw-in side. In addition, the support sleeve should be fixed more securely in the bore.

To solve this problem, the invention proposes a pipe connection connection in which the connection housing is designed as a pipe connection piece with a continuous bore, which has an insertion opening for the pipe end on its front connection side and is provided with an external thread on its rear screw-in side, wherein in the bore, as seen from the connection side,

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• at least one sealing ring which is located in a circumferential groove in the bore wall and which seals against an inserted pipe end,

• a cutting ring with a forward-tapering outer clamping cone, which can be clamped in a corresponding inner cone section in the bore, so that it is radially pressed onto an inserted pipe end when moved forward,

• a support sleeve,

which has a sleeve part extending coaxially in the bore, onto which a

The tube inserted into the insertion opening can be pushed on,

- which has at least one insertion depth

has a boundary surface for an inserted pipe end,

- which have a stop with a forward-facing

axial ring surface, which can be supported against a ring step arranged in the bore and which forms the screw-in stop for the

cutting ring,

wherein the support sleeve is held axially between the ring step and fastening means 0 formed inside the bore.

The special feature of the pipe connection with the aforementioned inventive features is the arrangement and fixation of the support sleeve within the 5 through hole of the pipe connection housing. This results in advantages over the previously mentioned prior art, namely in terms of improved

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Functionality in the manufacture and use of the pipe connection socket.

A significant advantage of the pipe connection according to the invention is that the axial stop for limiting the insertion depth when inserting the support sleeve from the screw-in side, which in the prior art is formed by the outer face on the screw-in side, is now moved to the inside of the bore. This axial stop surface is provided in the bore by an annular step which is arranged at the screw-in side end of the inner cone section which accommodates the cutting ring. For this purpose, the bore is radially widened in steps at the screw-in side end of said inner cone section, so that an axial annular surface lies in front of the inner cone when viewed from the screw-in side. Between the annular step and the screw-in side, the bore has a cylindrical cross-section. The support sleeve can be inserted into this from behind, i.e. from the screw-in side, with a corresponding hollow cylindrical section. Its front face also has the shape of an axial ring surface, which axially abuts against the aforementioned ring step in the pipe connection piece when the support sleeve is inserted. This stop ensures that the support sleeve cannot penetrate into the inner cone section when inserted. This ensures that the cutting ring chambered in it has enough room to move. The front ring surface of the support sleeve protrudes radially inwards over the ring step so that the cutting ring chambered in the inner cone section 0 is prevented from falling out of the pipe connection piece on the screw-in side. The outer diameter of the cylindrical section of the support sleeve is matched to the inner diameter of the cylindrical section of the bore so that the support sleeve remains easy to insert and is held and centered radially.

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The fact that in the invention the axial stop of the support sleeve is arranged inside the bore, in contrast to the prior art, results in the extremely advantageous possibility of securing the support sleeve in the bore by fastening means which are also formed inside the bore cross-section and prevent the support sleeve from being pushed out of the screw-in opening of the bore or from falling out.

In the pipe connection piece according to the invention, the support sleeve is therefore fixed in the bore between the first-mentioned stop on the connection side, which is formed by the ring step, and the last-mentioned fastening means, which practically serve as a rear stop on the screw-in side. The functional elements for implementing these stops are, for the first time, all housed within the bore, i.e. in the connection housing. This results in a particularly compact structure, which can be designed in particular so that the support sleeve does not protrude beyond the end of the pipe connection piece on the screw-in side. The connection piece according to the invention also has a high level of functional reliability, since during assembly the support sleeve cannot be inserted too far at the internal insertion depth limiter by the ring step. Because the stops for positioning the support sleeve are completely relocated inside the connection housing, they are particularly well protected against damage, which is beneficial to the functionality and longevity of the pipe connection piece.

0 From a manufacturing point of view, the internal stops can be implemented with relatively little effort. However, no compromises are made in terms of functional reliability.

5 Preferably, the support sleeve is completely housed within the pipe connection piece. Thanks to the inventive internal arrangement of both the stop and the fastening means, this compact

Arrangement in which the support sleeve is countersunk in the bore or is flush with the front side of the connection housing can be implemented without problems, since external stops or similar external fastening means are not required, as in the prior art.

A particularly preferred embodiment of the invention provides that the fastening means are formed by material deformation on the screw-in side edge of the bore, which protrudes into the bore cross-section. This permanent plastic material deformation reduces the free cross-section of the bore opening on the screw-in side to such an extent that the support sleeve sitting in the bore can no longer be pushed out of the opening. The stop formed by the fastening means on the screw-in side is formed by the material cross-section protruding radially inwards. This design has the advantage that it requires little manufacturing effort and yet exerts a high holding force, so that the support sleeve is securely fixed axially.

The axial length of the cylindrical section of the support sleeve and the distance between the inner ring step, which forms the first stop, and the aforementioned material deformation is preferably selected so that the cylindrical holding section of the support sleeve is firmly clamped between the stop and the material cross-section formed for fastening. This ensures that the support sleeve is securely and clearly positioned, which is advantageous with regard to the assembly of a plastic pipe to be inserted.

One way to achieve the material deformation to form the fastening means is to caulk the edge areas of the hole. The front side is notched near the edge of the hole using a punch or chisel-like caulking tool, so that the material displaced in this way is plastically deformed inwards.

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into the bore cross-section and is pressed axially against the inserted support sleeve.

Preferably, several caulked areas are arranged symmetrically around the circumference of the hole edge.

Alternatively, it is possible to form the material deformation as a circumferential flanging of the edge. This flanging means that the entire edge area is pressed radially inwards. In practice, an annular web can be formed on the edge of the hole on the screw-in side, which is pressed inwards when flanging. This flanging is therefore roughly comparable to riveting the support sleeve in the pipe connection housing. The particular advantages of flanging are that the support sleeve is held particularly securely on the screw-in side by the annular circumferential material cross-section. Another benefit is that the deformation achieves a certain material hardening, for example with brass or other non-ferrous metals. From a manufacturing point of view, it is advantageous that in addition to the cutting ring and the support sleeve, no further fastening parts are required and the flanging can be carried out efficiently.

The material deformation, i.e. the caulked edge areas or the circumferential flanging, preferably rests against a holding surface of the support sleeve. This can be formed, for example, by a conical ring surface that is arranged on the outer edge of the screw-in face of the support sleeve. The conical design of the holding surface has the particular advantage that the flanging does not have to be at right angles, which prevents cracks from forming. In addition, the conical holding section supports particularly well.

An alternative possibility is that the fastening means comprise an internal thread in the bore,

into which the support sleeve, which is provided with a corresponding external thread, can be screwed. In this embodiment, the support sleeve is clamped against the stop by screwing it in. The threaded connection is also completely integrated into the interior of the pipe connection piece, which is only possible thanks to the inventive design of the stop on an internal ring step. The threaded connection has the advantage that it can be implemented with relatively little tool use. The use of thread locking agents ensures that the screwed-in support sleeve does not come loose on its own. Using appropriate tools, it is still possible to loosen the support sleeve if necessary, for example in order to rework a pipe connection by using a new cutting ring. For this purpose, the support sleeve is provided on the screw-in side with a tool attachment for a screw-in tool, for example an internal or external hexagon or with grooves on the front or the like for the attachment of an appropriate key.

The tool attachment is conveniently located within the bore cross-section, countersunk in the bore on the screw-in side, so that it does not protrude outwards.

Basically, when creating a screw-in plug connection according to the invention, assembly is carried out exclusively from the screw-in side, as is already known from the sequence of steps in principle from the aforementioned DE 33 25 350 C2. To do this, the seal, the cutting ring and the support sleeve are inserted one after the other. The required fixing of the support sleeve is achieved by the edge of the hole being plastically formed into the hole cross-section by caulking or crimping, or alternatively by screwing the support sleeve into the hole and securing it if necessary.

While the detachable connection in the state of the art according to the aforementioned DE 33 25 350 C2 is only a frictional connection,

The invention creates a simple and secure, positive locking connection by means of the stop ring inserted into the bore from the screw-in side. For this purpose, the cylindrical outer or holding section of the support sleeve, which sits in the cylindrical section of the bore with little radial play, is fixed on the connection side, i.e. from the front, by the stop and on the screw-in side, i.e. from the back, by the fastening means. These can have a permanent material deformation or a detachable threaded connection, each of which has specific advantages. In any case, the caulked edge areas, the flanged ring web or the threaded connection ensure that the support sleeve is fixed against axial displacement when loaded from the connection side, as occurs when the plastic pipe is connected. It cannot be pushed axially backwards out of the pipe connection socket, no matter how tightly the pipe end is inserted on the connection side.

Further advantageous embodiments provide that the sealing ring is designed as a tandem sealing ring with at least two axially consecutive individual O-sealing rings. This achieves an improved secondary seal.

The pipe connection piece is expediently provided with a sealing collar on the outside on the screw-in side. When screwing in the external thread, this serves as a sealing surface for a 0 sealing ring arranged on the external thread. The sealing collar is preferably formed by an axial surface of a hexagon screw head or the like.

The invention is explained in more detail below with reference to the drawing. The illustration in Fig. 1 shows a longitudinal section through a pipe connection according to the invention, which is provided as a whole with the reference number 1.

The pipe connection 1 has a pipe connection piece 2, which is designed as a tubular connection housing with a bore extending longitudinally. On the front face there is an insertion opening 3, into which a pipe end 4, preferably a plastic pipe, can be inserted longitudinally, as indicated by the arrow. In the screw-in side, rear area, the pipe connection piece 2 is provided with an external thread 5, which can be screwed into a pressure vessel (not shown) or the like.

In the front area of the pipe connection piece, a tandem sealing ring 6 is arranged in an annular groove, which is formed from two O-rings arranged one behind the other in the longitudinal direction. These are dimensioned in such a way that when a pipe end 4 is pushed in, they form a seal axially on the outside of the pipe end.

A cutting ring 8 is arranged in an inner cone section 7 of the bore, in which the inner wall of the bore tapers conically towards the insertion opening. This can be designed as a slotted metal ring, which is provided with an outer cone that can be pushed axially forwards 5 into the aforementioned inner cone section 7 and is thereby radially clamped. On the inside, the cutting ring 8 has sawtooth-like cutting edges directed backwards, which can be pressed into the outer wall of a pipe end 4.

A support sleeve 9 can also be inserted into the pipe connection piece 2 from the screw-in side. When inserted, this is supported by an externally circumferential axial ring surface serving as a stop 10 on a ring step 11 in the bore. At the same time, the stop 10 serves as the rear _o limitation of the inner cone section 7 and thus as a screw-in side movement limitation for the cutting ring.

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The pipe end 4 can be pushed onto the sleeve part 12 of the support sleeve 9, which extends coaxially forwards in the bore, up to the insertion depth limiting surface 13.

The support sleeve 9 is inserted and centered radially with its outer cylindrical area with a small amount of play in the cylindrical area 15 of the bore on the screw-in side. The support sleeve 9 is provided with a conical holding surface 16 on the outer edge of its rear end face.

A flange 17 of the material of the pipe connection piece 2 rests against this holding surface 16, i.e. a material cross-section that projects radially inwards into the bore cross-section. This flange 17 is formed by a material cross-section that is pressed radially inwards all the way around.

As can be seen from the illustration, the entire pipe connection, i.e. the pipe connection piece 2 with the cutting ring 8 and the support sleeve 9 fastened therein, has a particularly compact design. This support sleeve 9 is completely fixed within the pipe connection piece 2, namely on the connection side by the stop 10 resting on the ring step 11, and on the screw-in side by the flange 17, which rests against the conical holding surface 16.

Due to the stop 10, which can be supported against the ring step 11 located inside the bore, an external stop as in the prior art is superfluous, i.e. the 0 support sleeve 9 no longer has to grip the pipe connection from the outside.

The function of the cutting ring 8 is ensured by the fact that the inner cone section 7 is chambered backwards by the stop 10.

A further embodiment of a pipe connection 1 according to the invention is shown in Fig. 2, wherein

the same parts, identical reference numerals are used. The fastening means for attaching the support sleeve 9 is a screw-in thread 18 which is formed by corresponding external and internal threads on the support sleeve 9 or in the screw-in side bore of the pipe connection piece 2. In this embodiment, the positioning of the support sleeve 9 on the connection side also takes place by contact with the stop surface 11, as in the embodiment according to Fig. 1. In contrast to this, however, the support sleeve 9 is secured on the screw-in side by the screw-in thread 18. The support sleeve 9 is provided on the screw-in side with a tool attachment, for example a hexagon socket, for screwing in and unscrewing. This tool attachment 19 is completely countersunk within the bore, so that in this embodiment too the support sleeve 9 is fastened solely by means arranged within the bore.

Claims (14)

1. Pipe connection connection ( 1 ) for plugging in a pipe end ( 4 ) made in particular of plastic, in which the connection housing is designed as a pipe connection piece ( 2 ) with a through-bore, which has an insertion opening ( 3 ) for the pipe end ( 4 ) on its front connection side and is provided with an external thread ( 5 ) on its rear screw-in side, wherein in the bore, as seen from the connection side, - at least one sealing ring ( 6 ) which lies in a circumferential groove in the bore wall and seals against an inserted pipe end ( 4 ), - a cutting ring ( 8 ) with a forward-tapering outer clamping cone which can be clamped in a corresponding inner cone section ( 7 ) in the bore so that it is radially pressed onto an inserted pipe end ( 4 ) when displaced forwards. - a support sleeve ( 9 ), - which has a sleeve part ( 12 ) extending coaxially in the bore, onto which a pipe end ( 4 ) inserted into the insertion opening ( 3 ) can be pushed, - which has at least one insertion depth limiting surface ( 13 ) for an inserted pipe end ( 4 ), - which has a stop ( 10 ) with a forward-facing axial ring surface which can be supported against an annular step ( 11 ) arranged in the bore and which has the screw-in side stop for the cutting ring ( 8 ), wherein the support sleeve is held axially between the annular step ( 11 ) and fastening means formed inside the bore. 2. Pipe connection according to claim 1, characterized in that the support sleeve ( 9 ) is completely accommodated within the pipe connection piece ( 2 ). 3. Pipe connection according to claim 1 or 2, characterized in that the fastening means are formed by material deformation ( 17 ) on the screw-in side edge of the bore, which protrude into the bore cross-section. 4. Pipe connection according to claim 3, characterized in that a cylindrical outer section ( 14 ) of the support sleeve ( 9 ) is firmly clamped between the stop ( 10 ) and the material deformation ( 17 ). 5. Pipe connection according to claim 3, characterized in that the material deformation ( 17 ) is formed by caulked edge regions. 6. Pipe connection according to claim 3, characterized in that the material deformation is designed as a circumferential flanging ( 17 ) of the edge. 7. Pipe connection according to one of claims 3 to 6, characterized in that the material deformation ( 17 ) rests against a holding surface ( 16 ) of the support sleeve ( 9 ). 8. Pipe connection according to claim 7, characterized in that the holding surface ( 16 ) is formed by a conical annular surface. 9. Pipe connection according to one of claims 1 to 3, characterized in that the fastening means comprise an internal thread ( 18 ) in the bore, into which the support sleeve ( 9 ) provided with a corresponding external thread ( 18 ) can be screwed. 10. Pipe connection according to claim 9, characterized in that the support sleeve ( 9 ) has a tool attachment ( 19 ) for a screwing-in tool on the screw-in side. 11. Pipe connection according to claim 10, characterized in that the tool attachment ( 19 ) lies within the bore cross-section. 12. Pipe connection according to claim 10, characterized in that the tool attachment ( 19 ) is countersunk in the bore on the screw-in side. 13. Pipe connection according to claim 1, characterized in that the sealing ring ( 6 ) is designed as a tandem sealing ring with at least two axially successive individual sealing rings. 14. Pipe connection according to claim 1, characterized in that the pipe connection piece ( 2 ) has a circumferential sealing collar on the screw-in side.