DE2215584A1 - Method and device for the production of socket ends on self-contained profiles - Google Patents

Description

Hanover, March 28, 1972

ilieber & Sen Plastic-Industri A / S, Nestegt 3OUO Bergen, Norway

Method and device for the production of socket ends on self-contained profiles,

The invention relates to a method for producing radially expanded, dimensionally and dimensionally stable their inside calibrated and reinforced sleeve ends on self-contained profiles, in which in the Profile end an inner molded part remains that has the required dimensional tolerances after the profile end has been shaped and which forms an immovable, shape-retaining inner reinforcement in the shaped end of the profile which sits under pretension in the end of the profile.

The self-contained profiles are preferably to pipes made of thermoplastic material, so that the process according to the invention in particular for itohr production suitable is. However, it can also be used in the manufacture of other products, for example

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in the production of containers od, like.

The manufacture of spigot end pipes for use in socket connections is currently carried out in a variety of ways. The most widely used method is that the end of a longer pipe section is heated and directly deformed into a radial expansion with an inner annular groove for on na lime of a sealing ring which forms a seal between the
the pipe end having the socket end and that pipe end which are received by the socket end
target. Since such a radial local expansion of the
Pipe wall leads to the fact that the pipe wall is correspondingly thinner, this results in a weakening of the
earring. To such a weakening of the Rohrwaudung
To compensate, it is customary to reinforce the ear that is to be expanded. This can be done by local thickening of the xiohrwandung at the points of the
Pipe, which are later to be expanded radially
are done by locally compressing the pipe sections during the manufacture of the jar, as described in Norwegian patent application no. 143,0002
is.

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Another known method is that before the widening of the sweeping end a short pipe section is pushed or screwed onto the dumbbell, so that the tip section during subsequent shaping at the same time adapts to the contours of the .Röhrendes and since it forms an external reinforcement of the tube end.

These known expansion methods have the disadvantage that the entire length of the ear must be moved in order to achieve the necessary To be able to work on the limited end section of the itohr in special machines «

The invention is accordingly based on the object of a simple, easy and inexpensive manufacturing process for the production of socket ends on drilling and similar products, in which the required expansion go on without moving great lengths of head can * Here the respective liohrleitungsende should be so required that it is used as a spigot end for a tight, but nevertheless easily detachable socket connection between can serve two liohrleitungsabschnitts, wherein such hoof connections can optionally also be glued together meant to be.

This Aul '/ tabe is inventively achieved in that the oil-i'iiriit n? The profile end is pushed,

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while this is in the heated state and that directly during the insertion process, a radially expanded end sleeve portion is formed, the one Forms a tight permanent connection with the molded part.

The molding of the socket on the pipe end is thus carried out in two stages, namely by the calibrated molded part, which accommodate the seal, and the inside the sleeve is to form, is manufactured in a first stage as a separate part and after which in a second stage the molded part is pushed into the pipe end.

This process makes it considerably easier, faster and cheaper to form sleeves onto the pipe ends, because the molded part can be produced independently of the pipe length and the pipes do not have to be moved for this purpose The molding itself can take place on the spot. Since the production of the molded part is not tied to the pipe production, it can be produced in any way, for example by injection molding or by Die-casting, rolling, widening or the like and, in particular, also consist of a different material than the pipe can also meet optimal requirements in terms of strength, Dimensional and form tolerance as well as dimensional stability etc. to be fully fulfilled.

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When connecting pipes, it is important that the inner surfaces of the pipe sections and the other connecting parts are aligned as much as possible, so that a uniform and continuous guide surface within the pipeline is reached.

Furthermore, pipe sleeves, for example in the case of pressurized water pipes, meet the corresponding requirements in terms of strength and impermeability. When with the invention The pipe end is reinforced with the pipe wall through the molded part over the entire length of the radially expanded section is supported. When the molded part is additionally reinforced with regard to the internal pressure in the pipeline must, it can be fitted with a spherical sealing element arranged at right angles to the axis of the pipe that end are provided which is first introduced into the heated pipe end during the expansion process, so that no pressure can build up in the capillary gap formed between the molded part and the tube.

In addition, the method according to the invention is a effective seal between the molded part and the drill is achieved because the heated pipe due to its elastic

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Properties during the deformation process by themselves the contour of the molded part adapts and presses against the sealing element, so that no special dimensional tolerances for the seal to be complied with,

The known expansion method in which thickened pipe end sections are used to reduce the Wall thickness when forming a radially expanded To compensate for the end of the sleeve have the further disadvantage that it is precisely this section of the pipe that heats becomes, which is an undesirable extension due to the particularly low thermal conductivity of the thermoplastic material the heating period conditional * With the inventive This disadvantage is avoided by using the molded part, because the pipe material is thickened at the end of the pipe is not needed and thus the heating time does not need to be extended.

Another disadvantage of the known methods is that the thickened and shaped but still warm pipe end must be cooled down again and that the shaped pipe end must be held during the cooling period by the shaping element, since the pipe end only after cooling maintains its stable shape. Appropriate measures

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are not necessary in the method according to the invention, because the shaping element as a shape-retaining inner Reinforcement remains in the end of the profile formed in this way.

In addition, since in the known methods the shaping elements do not remain in the drilling end after shaping can, but on the contrary must be used for new drill bits, is the efficiency of the manufacturing machine relatively small · In the known processes, the molding of the sleeves on the pipe ends forms one Bottleneck in pipe production »

The long heating and cooling periods in the known methods have meant that only by using the desired shaping of the pipe ends directly in the continuous process step of particularly complicated machines is achievable in the context of pipe production. As a result of the capital-intensive facilities required for an automatic Forming the pipe ends must be created in a continuous pipe manufacturing process currently in the majority of companies the fitting of the sleeves is carried out to a large extent by hand and usually one operator is required per sleeve manufacturing machine, with the machines heating up for a long time and in particular have long cooling periods, so that the process is particularly complex and expensive.

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In contrast to this, the heating time is relatively short in the method according to the invention, since the heating up time The end of the pipe is not thicker than the rest of the drill hole and the cooling time is no longer of any practical importance, as that Pipe can be brought directly into storage after inserting the molded part »

The low thermal conductivity of the thermoplastic Materials enables the molded part to be made of the same thermoplastic material and with the same wall thickness how the pipe can be made without having to be cooled rapidly after molding to ensure the durability of the shape.

With the method according to the invention it is possible in simple and cheap way a fully automatic process for the production of socket ends on pipes directly to bring about in the pipe production in a stage with the rest of the production speed, since the heat content, which in this stage of production in the Pipe is already present, can be used in the expansion with use. Since the insertion of the dimensionally stable and shaping molding can easily be carried out by hand in a heated pipe end, too when there are long pipes, the inven-

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The method according to the invention allows the sleeves to be attached directly to a particular one without any complicated equipment Location, for example by users directly at the workplace, provided that only a suitable heat source is available Heating the drill ends is available as hot Oil, a propane gas flame or the like. This in turn also gives the users the possibility to use pipe lengths in a simple and cheap way and to provide them with sleeves, which one had to split for equipment purposes and therefore do not have a socket end.

An apparatus for carrying out the invention The process consists of a separately formed, dimensionally and dimensionally stable molded part that has the required dimensional tolerances and is provided with a sleeve portion which has a cylindrical inner surface into which a groove for receiving a sealing ring is formed and which has a cylindrical outer surface with an annular, having radially outwardly extending bead, it is provided according to the invention that the molded part has a cylindrical stepped portion which is opposite to the sleeve portion by an inclined Connection portion is stepped and which has a cylindrical inner surface which is in alignment with the inner surface a non-expanded profile end can be brought, wherein the stepped section has a tapered thrust

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has surface that extends from the inner surface to a corresponding cylindrical outer surface.

In order to achieve an anchoring against axial displacement in addition to the anchoring caused by the frictional forces that occur between the shaped pipe end and the molded part as a result of the tangential stresses in the elastic pipe wall of the pipe end, the molded part can be provided with one or more lateral beads or ribs be provided. Such bead or rib formations, which are formed on the outside of the molded part, can form a widened spherical groove on the inside of the molded part, which lies in a plane at right angles to the longitudinal axis of the pipe and is used in a known manner to accommodate inner seals .

If there are no special requirements regarding the sealing between the expanded pipe end and the molded part connected to it, it is unnecessary to provide the molded part with a sealing element opposite the connected expanded pipe end if the molded part has a local, radially widened bead at right angles to the axis of the pipe is provided, since the internal pressure in the pipeline will try to push the molded part out of the pipe end, so that the Yn'iderlager between the bead of the molded part and the correspondingly shaped

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Groove in the pipe end leads to a self-sealing »

But it is a seal between the expanded pipe end and the associated molded part required, that can The molded part must be provided with a conically tapering pushing surface at its end which is at the front during the insertion process, a radial spherical groove for receiving a separate seal is provided in or on this surface can be.

The invention is explained in more detail below using an exemplary embodiment in the drawing.

Fig. 1 shows in section a molded part immediately before it is inserted into a heated pipe end will.

Fig. 2 shows in section the molded part according to Fig. 1,

teÜYieise into the warmed, thereby deformed Tube end pushed in.

Fig. 3 shows in section the molded part according to FIG. 1, completely inserted into the heated pipe end.

FIG. 4 shows in section a pipe connection in which the pipe end shown in FIG. 3 is used

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Fig. 5 shows in section the temperature distribution along the heated pipe end and the Molded part.

One end 10 of a pipe made of thermoplastic material is shown in FIG. 1. In the embodiment shown, rigid polyvinyl chloride is used as a thermoplastic material, but any suitable thermoplastic material such as polyethylene can be used. The depicted End 10 has the same thickness and the same cross-section as the rest of the pipe and is in the heated state « Part of the heat content can be derived from a previous one Pipe manufacturing stage originate. But the heat can also by reheating after a previous cooling down and, if necessary, after a longer interim storage period are fed.

With a separately produced shape and dimensionally stable and precisely shaped molded part is designated, which is used as a molded body and as a reinforcing body that has the necessary dimensional and shape tolerances.

In the embodiment shown, the molded part is made thermoplastic material by forming short lengths of pipe

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made from rigid polyvinyl chloride. Alternatively, the molded part 11 can be made in other ways and made of other materials be made, for example in the form of injection-molded sleeves made of acrylonitrile-butadiene-styrene copolymer or made of reinforced thermosetting plastic, such as glass fiber reinforced Polyester or in the form of rolled or cast sleeves made of aluminum or some other metallic material Material.

In the embodiment shown, the molding is provided with a first cylindrical surface 12 at one end and with another radially expanded cylindrical one Inner surface at the other end and with correspondingly stepped cylindrical outer surfaces 14 and 15 on the outside opposite the inner surfaces 12 and 13. Between the inner surfaces 12 and 13 and accordingly between the outer surfaces 14 and 15 is an inclined connecting portion l6. The inner surface 13 is with a iiingnut 17 which receives a sealing ring 18 .

Accordingly, an annular bead or lip 17a is formed on the outer surface 15. The outer surface 14 is for outer end beveled towards the inner surface 12, so that a conical surface 19 is formed.

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In a recess 20 in the surface 19 is a band-shaped Sealing ring 21 attached.

In Figure 2 it is shown how the heated pipe end outside on the permanently shaped molded part 11 by pushing of the molded part 11 slides into the pipe end 10. The pipe end slides along the sealing ring 21, the surface 19 and the outer surface 15 as well as up along the bead or rib 17a.

In Figure 3, the molded part 11 is shown after it has been brought into position in the pipe end and an internal seal between the inner surface of the pipe 10 and the sealing ring 21 is made. The pipe end sits tightly on the fitting along its entire length and after cooling is fixed in its position in relation to the molded part.

The bead or itippe 17a serves as an anchoring element, which prevents axial displacement between the fitting and the pipe end after the expanded shape of the Pipe end is fixed by cooling. The cooling can be brought about by free air convection. A mutual Rotation between the molded part and the pipe end can be achieved, for example, by the arrangement of radial projections or indentations on the outside of the molded part can be prevented.

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In Figure 4, a pipe connection is shown which is designed so that there are no tensile forces between the connected pipes can transfer and which allows easy disassembly and assembly of the pipes. Bs an unmachined pipe end 23 is shown, which is covered in a machined pipe end 24 according to Figure 3,

The sealing ring 18 forms a seal between the pipe ends 23 and 24 in a known manner.

In Figure 5 is on a tube made of rigid polyvinyl chloride the heating process according to the invention shown with locally limited heating stages is carried out. As

from Figure 5, the section a_ is not heated, the section b_ to about 120 Q der and the section d to about 200 * 6.

section b_ to about 120 ° Q, section £ to about 150 ° C

A molded part made of the same thermoplastic material as the pipe and with the same wall thickness can be used without the risk of temperature deformation when cooling the socket end by means of free air convection there is only moderate heating of the molded part due to the low thermal conductivity in the thermoplastic material occurs and thus an exact dimensional tolerance can be ensured for the molded parts. In Figure 5 it is shown that the maximum temperature on the inner surface of the

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Molding in zones b_, £ and d_ about 3Q * ^ O Wd 60 C achieved, as measured in practical tests with heat transfer from the heated pipe end. The heating shown in Figure 5 does not affect the dimensional tolerance of the molded part

As a result of the powerful expansion which the pipe end is subjected to when it is pushed onto the prefabricated molded part, pipes that have a relatively small Have thickness and consist of a relatively soft material with little dimensional stability, so large axial forces occur that the heated pipe end expands and without special heating and formation of the molded part curls so that it does not withstand the forces of delay can and accordingly cannot be pushed onto the molded part.

The criterion for carrying out the method is that the diameter of the molded part at the insertion end is sufficiently small and gradually increases and that the temperature and the lengths of the steps in the individual zones _b, £ and <1 at the pipe end are adapted to one another are. The end of the pipe is the warmest in zone jd and the temperature falls backwards with each step up to zone a_ that has room temperature.

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The lengths of the steps on the inner molding are chosen so that the heated pipe end the axial thrust force in the can accommodate individual sections without puckering. Since the zone jl of the tube end must be heated to such an extent that the Largest diameter can be achieved, the risk of crimping is so great that the pipe end through the cylindrical Portion of the inner molding in the zone j2 are worn must and the length of this zone must be adapted to the length of the zone £. The same considerations apply to the zone £ applicable.

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Claims (4)

Hanover, March 28, 1972 Rieber & Sen Plastic-Industri A / S, Nestegt, 58, Bergen, Norway claims 1. Process for the production of radially expanded, Shape and dimensionally stable, on their inside calibrated and reinforced socket ends on self-contained Profiles in which an inner molded part remains in the profile end, which has the required dimensional tolerances after the profile end has been shaped and this is an immovable, shape-retaining inner reinforcement forms in the shaped end of the profile, which sits under prestress in the end of the profile, characterized in that the molded part is pushed into the profile end while this is in the heated state and that directly a radially widened one during the insertion process End socket section is formed, which has a sealing seat Forms permanent connection with the molded part. 2. The method according to claim 1, characterized in that the heated end of the profile immediately before the 209841/0874 gangway is not widened, 3 «The method according to claim 1 or 2, characterized in that the self-contained profile from a drill thermoplastic material is. 4. The method according to claim 1, 2 or 3 »characterized in that sections of the heated profile end each step of a local radial expansion during the axial pushing-on process of the profile end are subjected to the molded part, the widening along inclined inclined surfaces with a axial displacement in between takes place along an adjoining support surface, 5, molded part for carrying out the method according to a of claims 1 to 4, the separately molded, molded and is dimensionally stable with the required dimensional tolerances and provided with a socket section, one cylindrical inner surface with a groove for receiving a sealing ring and one cylindrical Outer surface with an annular, extending radially has an externally extending bead, characterized in that the molded part (ll) has a cylindrical offset Section (l2, l4), which is opposite to the socket 41/087 /; section is stepped by an inclined connecting portion (ivj) and which has a cylindrical inner surface (l2) which can be brought into alignment with the inner surface of a non-expanded profile end, wherein the stepped section has a conically tapering bchubfii'.ciie (19), which from ('.er inner surface (12) to zii a corresponding cylindrical outer surface (l4) wealth. 0, i'ormtei] according to spoke 5, characterized in that! in or au.P the conically tapering bchubflache (ly) a radial spherical groove for receiving a separate Liiclitun / i ('' i) is provided. 209B4 1/0 8 7 r ,,