WO2000028252A1 - Longitudinal non-positive plug-in bushing - Google Patents

Abstract

Disclosed is a plastic bushing (1) used to join plastic pipes (4) that have the same or approximately the same diameter for pressure-conducting fluids such as drinking water or waste water. Said bushing is provided with an enlargement (2) and a sealing ring (5) together with a clamping ring (6) for pressure tight, longitudinal non-positive accommodation of a plastic pipe (4) that is to be connected. A reducing section (3) is provided on said bushing (1) between the enlargement (2) and the plastic pipe (4) that is to be connected. The bushing (1) is also provided with a reinforcement (7) that receives radial pressure forces. The reinforcement (7) is imbedded into the plastic of said bushing (1) as an integral component.

Description

 Restrained push-in socket

The invention relates to a plastic sleeve for connecting plastic pipes of the same or approximately the same diameter for pressurized fluids, such as drinking or waste water, which plastic sleeve is provided with a widening and a sealing and a clamping ring for the pressure-tight and restrained reception of the plastic pipe to be connected, whereby a reduction section is provided between the widening and the plastic pipe on which the sleeve is arranged, and the sleeve is provided with a reinforcing part that absorbs radial compressive forces.

Push-in sleeves of the aforementioned type made of plastic for pressure pipelines in water supply or in sewage systems are known. As a rule, they have an expansion into which the next plastic tube is inserted. A sealing ring and a clamping ring are provided there. The sealing ring seals the medium transported in the pipeline from the environment. The clamping ring provides the required restrained force to ensure a reliable connection of the individual plastic pipes of the piping system created with them and to prevent the pipes from sliding apart.

By inserting the plastic pipes into the sleeves, radially outward pressure forces are introduced into the widening of the sleeve, which by definition have to reach a certain order of magnitude in order to bring about the desired restrained connection of the connection. As a result, there is a risk of the sleeve tearing, particularly in the area of the expansion. To prevent this from happening, it is known to muffle the in question standing type after inserting a plastic tube into the sleeve subsequently with such a radial pressure forces absorbing reinforcement part. This consists of two shell halves, which are placed around the sleeve and screwed together. The shell halves are loose parts that must be kept available together with screws, nuts, washers and spring washers as well as the necessary tools. The application of the reinforcement part is also a time-consuming work step, which prevents the rapid laying of the pipeline.

The object of the invention is to provide a push-in sleeve of the type mentioned, which enables a reliable restrained connection even of pressure-carrying lines and in which the additional application of a reinforcing part to the sleeve on the construction site can be dispensed with.

This object is achieved according to the invention in that the reinforcing part is embedded as an integral component in the plastic of the sleeve. The invention paves the way for installing a reinforcement part in the socket already during socket manufacture. This has the manufacturing advantage that a relatively simple, e.g. molded part made of sheet metal can be used. Before the injection molding, this molded part is placed in the injection mold and thus worked into the wall of the plastic sleeve according to the invention. The special application and screwing of the previously required shell halves is then no longer necessary at the construction site. The plastic pipeline can thus be laid quickly.

According to the invention, the reinforcement part is rotationally symmetrical and corresponds to the sleeve and extends along the widening and the reducing section of the sleeve. Even with this comparatively simple design of the reinforcement part, the compressive forces acting outwards by inserting the subsequent plastic pipe are reliably absorbed. A possible tearing of the expansion of the sleeve is thus reliably prevented. In the sense of the invention it is also possible to provide the reinforcement part with recesses. In the first place, they can be bores that penetrate the entire wall of the reinforcement part. On the one hand, this reduces the weight of the reinforcement part. Due to the plastic of the sleeve wall entering these recesses during injection molding of the sleeve, a particularly reliable connection of the sleeve wall and the reinforcing part is also brought about.

However, the object of the invention is also achieved in that the reinforcing part is provided on the outer surface of the sleeve. In this case too, the reinforcement part is inserted into the injection mold and in this way during the manufacturing process of the sleeve with its plastic wall, i.e. the expansion and, if necessary, the reducing section are firmly connected.

Another embodiment of the invention is characterized in that the reinforcing part can be screwed onto a thread provided on an outer surface of the sleeve. The thread can be sprayed onto this during the manufacture of the sleeve or can also be cut open subsequently. The reinforcing part can then - in the form of a further sleeve - be screwed onto the actual plastic sleeve in order to absorb the pressure forces acting radially outwards.

A modification of the basic idea of the invention for so-called double sleeves is also possible. These have the same inner diameter over their entire length. The formation of a reducing section can be dispensed with. The pipes to be functionally connected to each other are inserted into the socket from one side. Due to the existing clamping and sealing rings, there is then a liquid-tight and restrained connection. The reinforcing part of this double sleeve or double push-in sleeve absorbs the radial forces generated to the outside. The reinforcement part usually consists of metal, in particular sheet steel, aluminum sheet. The sheet can also be made of an aluminum alloy or another metallic alloy. In the case of the screwed-on reinforcement part mentioned, it can also consist of plastic of higher strength, for example polyacetal, polyamide or glass fiber reinforced plastic.

Further details, features and advantages of the invention will become apparent from the following description of several exemplary embodiments and from the schematic drawing and the claims. Here show, each in a partial longitudinal section:

Fig. 1 shows a first embodiment of the invention

Plastic sleeve with integrated reinforcement part;

Fig. 2-4 further embodiments of the sleeve according to the invention and

Fig. 5, the plastic sleeve according to the invention as a double sleeve.

1, a plastic sleeve or sleeve 1 according to the invention has an expansion 2 and a reducing section 3. To produce a plastic pipeline, which consists of several plastic pipes 4 with sleeves 1, a plastic pipe 4 'of the same dimension as the pipe 4 - is inserted into the widening 2. One or more clamping rings 5 or discrete clamping elements and a sealing ring 6 are overcome. The clamping rings or the clamping elements 5 lie tightly and firmly against an outer wall 8 of the inserted tube 4 '. The clamping ring 5 brings about the desired restrained connection, while the sealing ring 6, which can be made of rubber, brings about a liquid-tight seal between the sleeve 1 and the inserted pipe 4 '. The clamping rings or clamping elements 5 can consist, for example, of corundum. A reinforcing part 7 is provided in the wall of the plastic sleeve 1. According to FIG. 1, it extends essentially over the widening 2 and the reducing section 3. It serves to absorb forces acting radially outwards, which arise from the insertion of the plastic pipe 4 ′ to be connected into the widening 2. The continuation of the reinforcement part 7 in the reducing section 2 ensures that there is no excessive material stress and cracking in the plastic of the sleeve 1 or the pipe 4 even when such radial forces are passed from the expansion 2 into the reducing section 3. The reinforcing part 7 can be made from a metal sheet and is arranged rotationally symmetrically in the sleeve 1, which is also rotationally symmetrical. It can be provided with recesses 15. This results in a reduction in weight of the part 7. The plastic of the sleeve 1 can penetrate into these recesses during the manufacturing process, so that there is a particularly intimate and firm connection between the reinforcing part 7 and the plastic sleeve 1. 1 can be formed from a metal sheet, for example steel sheet. Grooves for receiving one or more clamping rings 5 or discrete clamping elements 5 and for receiving the sealing ring 6 are provided in the sleeve 1 itself.

FIG. 2 shows an embodiment of the plastic sleeve 1 according to the invention that is modified from the object of FIG. 1. The reinforcement part 7 is designed with several undercuts 9, which are filled with plastic during the injection molding process. This leads to the necessary anchoring between the plastic sleeve 1 and the reinforcement part 7. In the area of the reducer 3, the reinforcement part is designed similarly to that shown in FIG. 7. In the exemplary embodiment shown, ring grooves for receiving the Klernm rings 5 or discrete clamping elements 5 and the sealing ring 6 are also provided in the reinforcement part 7. In the area of the outer surface of the sleeve 1, the reinforcing part 7 is surrounded by plastic. The inner surface of the sleeve 1, as shown, is partially formed by the reinforcing part 7, which is not embedded there in the plastic of the sleeve 1. The situation is opposite in the exemplary embodiment according to FIG. 3. The reinforcing part 7 is provided there on the outer surface of the sleeve 1. The connection with the plastic of the sleeve 1 is in turn effected via undercuts or annular grooves 9, which are filled with plastic during the injection molding process. Similar to the subject of FIG. 1, here again grooves for the clamping rings 5 and the sealing ring 6 are provided in the plastic of the sleeve 1, that is to say the widening 2 thereof. 4, a thread 10 is provided on the circumference thereof. It can be inserted into the manufacturing mold as a prefabricated insert for the injection mold of the sleeve 1 before the actual injection molding process, so that it is connected to the sleeve 1 in this way. However, it can also be shaped by the design of the injection mold or subsequently cut open on the sleeve. In any case, it serves to subsequently screw the reinforcement part 7 onto the sleeve 1. In the illustrated embodiment, the armoring part 7 is designed so that it serves to receive the clamping ring 5 at the same time. The sealing ring 6 is provided in a separate groove in the plastic sleeve 1, ie in its widening 7.

Fig. 5 shows a modified embodiment of the basic idea of the invention. A double sleeve 20 is used for blunt mating two plastic pipes 4 using the principles of the invention described above. The reinforcing part 7 is symmetrical for receiving sealing rings 5 and 6 clamping rings. Its inner surface forms the contact surface for the two pipes to be inserted. The reinforcement part 7 is extrusion-coated with plastic on the outer circumference. It in turn has undercuts or annular grooves 9, by means of which it is firmly arranged in the plastic sleeve 20.

Sleeve 1 and pipe 4 or 4 'are made of conventional thermoplastic, such as polyethylene. In addition to the corundum already mentioned, the clamping ring or the clamping elements 5 can also be made, for example, of polyoxymethylene (glass fiber reinforced). The sleeve according to the invention can either be molded on-line directly to the tube following the extrusion of the tube. It is also possible to manufacture the sleeve in a separate work step from the pipe production and then butt weld it to one another at the transition area between the reducing section 3 and the pipe 4.

It is also possible to prefabricate the reinforcing part 7, in particular in the case of FIG. 3, from glass fiber-reinforced plastic and to use it as an insert for the injection mold of the sleeve 1.

Basically, it should be noted that the reinforcing part 7 is injected into the sleeve 1 during the manufacturing process. This results in a rational strengthening of the sleeve according to the invention and a sufficiently non-positive connection between the plastic of the sleeve 1 and the reinforcing part 7.

Claims

claims 1.Plastic sleeve (1) for connecting plastic pipes (4) of the same or approximately the same diameter for pressurized fluids, such as drinking or waste water, the plastic sleeve (1) for the pressure-tight and restrained reception of the plastic pipe (4, 4 ') to be connected with a Widening (2) and a sealing ring (5) and a clamping ring (6) is provided, a reducing section (3) being provided between the widening (2) and the plastic pipe (4) on which the sleeve (1) is provided and wherein the sleeve (1) is provided with a reinforcing part (7) which absorbs radial compressive forces, characterized in that the reinforcing part (7) is embedded as an integral component in the plastic of the sleeve (1). 2. A sleeve according to claim 1, characterized in that the reinforcing part (7) is provided within a wall of the sleeve (1) and is practically surrounded on all sides by plastic. 3. A sleeve according to claim 2, characterized in that the reinforcing part (7) is rotationally symmetrical and corresponding to the sleeve (1) and is provided along the widening (2) and the reducing section (3). 4. Sleeve according to at least one of claims 1 to 3, characterized in that the reinforcing part (7) is provided with recesses (8). 5. Sleeve according to at least one of claims 1, 3 or 4, characterized in that the reinforcing part (7) is provided on the outer surface of the sleeve (1). 6. Sleeve according to at least one of claims 1 to 5, characterized in that the reinforcing part (7) on an outer surface of the sleeve (1) provided thread (10) can be screwed. 7. Modification of the sleeve according to at least one of claims 1 to 6, characterized in that it is designed as a double sleeve (20).