CH632076A5

CH632076A5 - Pipe coupling

Info

Publication number: CH632076A5
Application number: CH1556477A
Authority: CH
Inventors: Karl Georg Dipl Ing Doutlik
Original assignee: Amiantus Ag
Priority date: 1976-12-24
Filing date: 1977-12-19
Publication date: 1982-09-15
Also published as: BE862248A; DE2756540A1; NL7714347A; AT347191B; ATA964876A

Description

Die Erfindung wird nachstehend an Hand der Zeichnung, in 65 der Ausführungsbeispiele der Erfindung dargestellt sind, näher beschrieben. The invention is described in more detail below with reference to the drawing, in which 65 of the exemplary embodiments of the invention are shown.

Es zeigen: Show it:

Fig. 1 eine Ansicht einer ersten Ausführungsform der erfin- 1 is a view of a first embodiment of the invented

632 076 632 076

dungsgemässen Rohrkupplung, teilweise im axialen Längsschnitt, pipe coupling according to the invention, partly in axial longitudinal section,

Fig. 2 einen Schnitt entlang der Linie II-II in Fig. 1, 2 shows a section along the line II-II in FIG. 1,

Fig. 3 eine Teilansicht einer zweiten Ausführungsform der erfindungsgemässen Rohrkupplung, teilweise in aufgerissener Darstellung und Fig. 3 is a partial view of a second embodiment of the pipe coupling according to the invention, partly in a torn view and

Fig. 4 einen Schnitt entlang der Linie IV—IV in Fig. 3. FIG. 4 shows a section along the line IV-IV in FIG. 3.

Die in den Fig. 1 und 2 dargestellte erste Ausführungsform der erfindungsgemässen Rohrkupplung, welche zum dichten Verbinden der Enden von zwei nicht dargestellten Rohren, insbesondere von Faser- bzw. Asbestzementrohren, dient, besteht aus einer rohrförmigen Hülse 1, deren Innendurchmesser so gewählt ist, dass die Hülse auf die zu verbindenden Rohre aufgeschoben bzw. übergeschoben werden kann. An ihrem inneren Umfang, d.h. der inneren Mantelfläche 1', ist die rohrförmige Hülse 1 mit zwei im Abstand voneinander angeordneten, über den gesamten Umfang umlaufenden Kammern bzw. Vertiefungen 3 zur Aufnahme von gleichfalls nicht dargestellten Dichtringen versehen, welche einen dichten Abschluss zwischen der Oberfläche der zu verbindenden Rohre und der Innenfläche der Hülse ermöglichen. Zwecks Erleichterung des Einbringens der Dichtringe sind die Vertiefungen 3, die an sich im wesentlichen rechteckförmigen Querschnitt haben, einseitig mit einer Schrägfläche 4 abgeschrägt. Diese Schrägfläche erlaubt auch ein Ausweichen des Dichtringes bei seiner Verformung. An der äusseren Mantelfläche 1" sind im Bereich der Kammern 3 zwecks Erhaltung einer gleichen Wandstärke rundumlaufende Wandvorsprünge 5a vorgesehen. 1 and 2, the first embodiment of the pipe coupling according to the invention, which serves for the tight connection of the ends of two pipes, not shown, in particular of fiber or asbestos cement pipes, consists of a tubular sleeve 1, the inside diameter of which is chosen so that that the sleeve can be pushed or pushed over the pipes to be connected. On their inner circumference, i.e. the inner circumferential surface 1 ', the tubular sleeve 1 is provided with two spaced apart, circumferential chambers or recesses 3 for receiving sealing rings, also not shown, which provide a tight seal between the surface of the pipes to be connected and the Allow inner surface of the sleeve. In order to facilitate the insertion of the sealing rings, the depressions 3, which are essentially rectangular in cross section, are beveled on one side with an inclined surface 4. This inclined surface also allows the sealing ring to deflect when it is deformed. On the outer circumferential surface 1 ″, all-round wall projections 5a are provided in the area of the chambers 3 in order to maintain the same wall thickness.

In axialer Richtung in der Mitte der Hülse 1 sind im Abstand voneinander angeordnete einzelne Mittelanschläge bzw. Distanzelemente 14a, 15a vorgesehen, die so ausgebildet sind, dass beim Aufschieben der Kupplung auf ein Rohrende jene mutas zu diesen Distanzelementen aufgeschoben werden kann. Dadurch wird erreicht, dass die Kupplung gleich weit über beide zu verbindenden Rohrenden übergreift. Dadurch kann beispielsweise der bei den Kupplungshülsen aus Asbestzement übliche Distanzring aus Gummi entfallen. In the axial direction in the middle of the sleeve 1, spaced apart individual center stops or spacer elements 14a, 15a are provided, which are designed such that when the coupling is pushed onto a pipe end, those mutas can be pushed onto these spacer elements. This ensures that the coupling extends equally far over both pipe ends to be connected. This means, for example, that the rubber spacer ring, which is common in coupling sleeves made of asbestos cement, can be omitted.

Die Distanzelemente 14a, 15a bestehen aus vier Gruppen von je drei rippenförmigen Vorsprüngen, welche Gruppen in Viertelkreis-Abständen über die innere Mantelfläche 1' verteilt sind. Die drei Vorsprünge jeder Gruppe sind relativ nahe aneinander angeordnet und können - so wie in Fig. 2 dargestellt -radial zum Mittelpunkt der Kupplung oder auch parallel zueinander, nämlich senkrecht zum horizontalen Durchmesser in Fig. 2 orientiert sein. Die Wandstärke der rippenförmigen Vorsprünge ist der durchschnittlichen Wandstärke der gesamten Kupplung etwa gleich gewählt. Die Vorsprünge sind an ihren den Stirnseiten der in die Kupplung einzuschiebenden Rohre zugewandten Hanken abgeschrägt, um eine Zentrierung der Rohrenden zu gewährleisten. Jeder der rippenförmigen Vorsprünge weist im axialen Längsschnitt ein trapezförmiges Profil auf, das auch zu einem Dreieck entarten kann. The spacer elements 14a, 15a consist of four groups of three rib-shaped projections each, which groups are distributed at quarter-circle intervals over the inner lateral surface 1 '. The three projections of each group are arranged relatively close to one another and can - as shown in FIG. 2 - be oriented radially to the center of the coupling or also parallel to one another, namely perpendicular to the horizontal diameter in FIG. 2. The wall thickness of the rib-shaped projections is chosen to be approximately the same as the average wall thickness of the entire coupling. The projections are chamfered on their sides facing the end faces of the pipes to be inserted into the coupling in order to ensure centering of the pipe ends. Each of the rib-shaped projections has a trapezoidal profile in the axial longitudinal section, which can also degenerate into a triangle.

Sollte es erforderlich sein, die Kupplung ganz auf ein Rohrende zu überschieben, so können die Distanzelemente 14a, 15a einfach mit einer Raspel abgeschliffen werden. If it is necessary to push the coupling all the way onto one pipe end, the spacer elements 14a, 15a can simply be ground off with a rasp.

Die gesamte Rohrkupplung gemäss den Fig. 1 und 2 ist einstückig aus vorzugsweise kompakt gespritztem Polypropylen hergestellt. Dieses Material hat sich infolge seiner Wärmebeständigkeit und Widerstandsfähigkeit als besonders geeignet erwiesen. The entire pipe coupling according to FIGS. 1 and 2 is made in one piece from preferably compact injection molded polypropylene. This material has proven to be particularly suitable due to its heat resistance and durability.

Die in den Fig. 3 und 4 dargestellte weitere Ausführungsform einer erfindungsgemässen Rohrkupplung besteht ebenfalls aus einer rohrförmigen Hülse 1, die mittels einer in einer axialen Ebene verlaufenden Trenn- bzw. Teilfuge 2 in zwei gleich ausgebildete Hälften, also praktisch in zwei Halbschalen, unterteilt ist. Zwecks Vereinfachung der Darstellung ist in der Zeichnung nur eine dieser Halbschalen voll dargestellt, während von der anderen Halbschale nur ein Teil derselben mit strickpunktierten The further embodiment of a pipe coupling according to the invention shown in FIGS. 3 and 4 also consists of a tubular sleeve 1, which is divided into two identically designed halves, that is to say practically into two half-shells, by means of a separating or parting joint 2 running in an axial plane . In order to simplify the illustration, only one of these half-shells is shown in full in the drawing, while only a part of the other half-shell is shown with dotted lines

Linien angedeutet ist. Der Innendurchmesser der Hülse 1 ist auch hier wie beim Ausführungsbeispiel gemäss den Fig. 1 und 2 gewölbt und es sind auch wieder die mit einer Schrägfläche 4 versehenen Vertiefungen 3 an der inneren Mantelfläche 1' vor-5 gesehen. (Gleiche Teile sind bei beiden Ausführungsbeispielen mit gleichen Bezugszeichen versehen). Lines is indicated. The inner diameter of the sleeve 1 is also curved here, as in the exemplary embodiment according to FIGS. 1 and 2, and the depressions 3 on the inner circumferential surface 1 ′ provided with an inclined surface 4 are also seen again. (Identical parts are provided with the same reference symbols in both exemplary embodiments).

An ihrer äusseren Mantelfläche 1", d.h. an ihrem äusseren Umfang, ist die rohrförmige Hülse 1 mit einer Mehrzahl von im Abstand voneinander angeordneten, dünnwandigen Rippen 5 io versehen, die im wesentlichen in radialen Ebenen der Hülse 1 verlaufen und sich über den gesamten Umfang erstrecken. Die Rippen 5 sind - vereinfacht gesprochen - Kreisringe, die auf den Umfang der Hülse 1 aufgesetzt sind. Dünnwandig bedeutet in diesem Zusammenhang, dass die in radialer Richtung gemes-15 sene Höhe der Rippen 5 grösser als die in axialer Richtung gemessene Dicke der Rippen ist. Der Abstand zwischen den einzelnen, nebeneinanderliegenden Rippen 5 ist dabei im wesentlichen gleich oder kleiner als ihre Höhe. Die an den axialen Stirnseiten der Hülse angeordneten Rippen 6,7 haben dabei 20 eine etwas grössere Dicke als die übrigen Rippen 5. Die in radialer Richtung gemessene Höhe der Rippen 5 ist grösser als diejenige der Rippen 6,7 was dadurch bedingt ist, dass die äussere Mantelfläche 1" der Hülse 1 abgestuft ausgebildet ist, um die am inneren Umfang 1' umlaufenden Vertiefungen 3 25 aufnehmen zu können. Die Rippen 5,6,7 sind mittels einer in axialer Richtung verlaufenden weiteren Rippe 8, welche eine geringere radiale Höhe als die erstgenannten Rippen aufweist, untereinander verbunden. Diese Rippe 8 verläuft in einer zur Trenn- bzw. Teilungsfuge 2 im wesentlichen senkrecht stehen-30 den Ebene. Es könnten jedoch auch mehrere solche in axialer Richtung verlaufende Rippen vorgesehen werden, die in gleichen oder ungleichen Abständen verteilt am Umfang der Hülse angeordnet werden können. Durch die Anordnung der im wesentlichen axial verlaufenden Rippe können einerseits die 35 Formhaltigkeit bzw. Steifigkeit der Rohrkupplung verbessert und anderseits der Materialfluss bei der Formgebung günstiger gestaltet werden. Bei der Herstellung der Rohrkupplung durch Giessen oder Spritzgiessen wird der Anguss vorzugsweise an diese erwähnte axiale Rippe angeschlossen. On its outer circumferential surface 1 ″, ie on its outer circumference, the tubular sleeve 1 is provided with a plurality of spaced-apart, thin-walled ribs 5 io, which run essentially in radial planes of the sleeve 1 and extend over the entire circumference To put it simply, the ribs 5 are circular rings which are placed on the circumference of the sleeve 1. In this context, thin-walled means that the height of the ribs 5 measured in the radial direction is greater than the thickness of the ribs measured in the axial direction The distance between the individual ribs 5 lying next to one another is essentially equal to or less than their height The ribs 6, 7 arranged on the axial end faces of the sleeve 20 have a somewhat greater thickness than the other ribs 5 The height of the ribs 5 measured in the direction is greater than that of the ribs 6, 7, which is due to the fact that the outer lateral surface 1 ″ of the sleeve 1 is graduated in order to be able to accommodate the recesses 3 25 running around the inner circumference 1 '. The ribs 5, 6, 7 are connected to one another by means of a further rib 8 running in the axial direction, which has a smaller radial height than the first-mentioned ribs. This rib 8 runs in a plane that is essentially perpendicular to the parting or dividing joint 2. However, several such ribs running in the axial direction could also be provided, which can be arranged at equal or unequal intervals on the circumference of the sleeve. The arrangement of the essentially axially extending rib on the one hand improves the shape retention or rigidity of the pipe coupling and on the other hand the material flow during shaping can be made more favorable. In the manufacture of the pipe coupling by casting or injection molding, the sprue is preferably connected to this axial rib mentioned.

40 Entlang der Trenn- bzw. Teilungsfuge 2 ist je ein in axialer Richtung verlaufender Flansch 9 vorgesehen. Anstelle dieses Flansches 9 könnte auch eine Leiste, Rippe od. dgl. vorgesehen werden. Wenn die rohrförmige Hülse einteilig ausgeführt wird, kann der Flansch auch entfallen. Der Flansch erstreckt sich über 45 die gesamte axiale Länge der Hülse 1 und seine radiale Breite bzw. Höhe entspricht der Höhe der Rippen 5. Um die beiden Halbschalen, welche die Rohrkupplung bilden, gegenseitig fixieren zu können, sind entlang des Flansches 9 im Abstand voneinander Vorsprünge 10 in Form von Zapfen od. dgl., und so entsprechende Vertiefungen 11 in Form von Bohrungen vorgesehen, wobei die Anordnung derart getroffen ist, dass beim Zusammenbau der die Rohrkupplung bildenden Halbschalen jeweils einer der Vorsprünge 10 mit einer der Vertiefungen 11-vorzugsweise mit Schiebesitz - in Eingriff kommt. Anstelle der 55 Zapfen od. dgl. könnten auch andere Führungselemente vorgesehen werden. Jeder der Zapfen od. dgl. 10 ist hohlzylindrisch ausgebildet, d.h. mit einer Bohrung 12 versehen, durch die zur Verbindung der Kupplungshälften Schrauben 13 gesteckt werden können, die dann mit Muttern versehen werden. Die Stoss-60 stellen können zur Verbesserung der Dichtheit vor dem Zusammenbau der Kupplungshälften auch mit einem entsprechenden Klebemittel bestrichen werden. 40 A flange 9 running in the axial direction is provided along the separating or dividing joint 2. Instead of this flange 9, a strip, rib or the like could also be provided. If the tubular sleeve is made in one piece, the flange can also be omitted. The flange extends over 45 the entire axial length of the sleeve 1 and its radial width or height corresponds to the height of the ribs 5. In order to be able to fix the two half-shells which form the pipe coupling to one another, there are spacings along the flange 9 Projections 10 in the form of pins or the like, and corresponding depressions 11 in the form of bores are provided, the arrangement being such that when the half-shells forming the pipe coupling are assembled, one of the projections 10 each with one of the depressions 11, preferably with Sliding seat - comes into engagement. Instead of the 55 pins or the like, other guide elements could also be provided. Each of the pins or the like 10 is hollow-cylindrical, i.e. provided with a bore 12 through which screws 13 can be inserted to connect the coupling halves, which are then provided with nuts. The Stoss-60 points can also be coated with an appropriate adhesive to improve the tightness before assembling the coupling halves.

In axialer Richtung in der Mitte der Hülse 1 sind wiederum im Abstand voneinander angeordnete, einzelne Mittelanschläge 65 bzw. Distanzelemente 14,15 angebracht, die so ausgebildet sind, dass beim Aufschieben der Kupplung auf ein Rohrende jene nur bis zu diesen Distanzelementen aufgeschoben werden kann. Dadurch wird - so wie beim Ausführungsbeispiel gemäss In the axial direction in the middle of the sleeve 1, individual center stops 65 or spacing elements 14, 15 are again arranged at a distance from one another, which are designed such that when the coupling is pushed onto a pipe end, it can only be pushed up to these spacing elements. As a result, as in the exemplary embodiment

den Fig. 1 und 2 - erreicht, dass die Kupplung gleich weit über beide zu verbindenden Rohrenden übergreift. Die Distanzelemente 14,15 sind wiederum an ihren den Stirnseiten der einzuschiebenden Rohre zugewandten Flanken abgeschrägt um eine Zentrierung der Rohre zu erzielen. Sollte es erforderlich sein, die Kupplung ganz auf ein Rohrende zu überschieben, so kann auch hier das bzw. können die Distanzelement(e) 14,15 einfach mit einer Raspel abgeschliffen werden. 1 and 2 - achieved that the coupling overlaps equally far over both pipe ends to be connected. The spacer elements 14, 15 are in turn beveled on their flanks facing the end faces of the tubes to be inserted in order to achieve a centering of the tubes. If it is necessary to push the coupling all the way onto one end of the pipe, the spacer element (s) 14, 15 can also be simply ground off with a rasp.

Die gesamte Rohrkupplung bzw. jede der beiden Halbschalen, kann einstückig aus geschäumtem Kunststoff hergestellt sein. Zur Herstellung kommen insbesondere Polyolefine, Polystyrol oder Polyvinylchlorid bzw. das vorher bereits erwähnte Polypropylen in Betracht. Es könnten jedoch auch andere thermoplastische oder duroplastische Kunststoffe verwendet werden. Es wird ausdrücklich festgehalten, dass im vorliegenden Zusammenhang unter dem Begriff Kunststoff auch Faserzement, insbesondere Asbestzement, verstanden wird, der im plastischen Zustand gleichfalls spritzfähig ist. Es ist in jedem Fall zweckmässig, jede Halbschale mit den Rippen, Flanschen, Vertiefungen, Anschlägen usw. einstückig herzustellen, d.h. in einem einzigen Arbeitsgang zu formen. The entire pipe coupling or each of the two half-shells can be made in one piece from foamed plastic. In particular, polyolefins, polystyrene or polyvinyl chloride or the previously mentioned polypropylene are suitable for the production. However, other thermoplastic or thermoset plastics could also be used. It is expressly stated that in the present context the term plastic also means fiber cement, in particular asbestos cement, which is also sprayable in the plastic state. In any case, it is expedient to manufacture each half-shell in one piece with the ribs, flanges, depressions, stops, etc. to form in a single operation.

5 632 076 5 632 076

Bei der Herstellung aus Kunststoff können die Kupplungshülsen in einem Stück fertiggestellt werden, wobei die Oberflächen genügend sauber sind, so dass eine Nachbearbeitung entfallen kann. Die Kupplungshülse kann auch in mehreren Teilen s gefertigt werden, um die bei der Herstellung in einem Stück wegen der ringförmigen Ausnehmungen an der Innenseite erforderliche, aufwendige Innenform zu vermeiden. Dieser Vorteil fällt vor allem dann ins Gewicht, wenn es sich um relativ geringe Stückzahlen handelt oder wenn die Leistung der Spritz-lo maschine durch das Spritzen mehrerer Einzelteile besser ausgenützt werden kann. Insbesondere bei komplizierten Ausführungen sind auch mehrere Teilungsebenen möglich. Die Verbindung der Einzelteile kann durch Verkleben, Verschrauben oder Verschweissen bzw. durch eine Kombination dieser Methoden 15 erfolgen. Als vorteilhaft erweist sich bei der Verklebung und Verschraubung eine Ausführung der Stossstelle mit Führungselementen, um das gegenseitige Verschieben der Einzelteile während des Zusammenbaues zu vermeiden. Beim Verschweissen werden die Einzelteile durch eine entsprechende Haltevor-20 richtung am Verschieben gehindert. In the case of production from plastic, the coupling sleeves can be finished in one piece, the surfaces being sufficiently clean that post-processing can be omitted. The coupling sleeve can also be manufactured in several parts s, in order to avoid the complex inner shape required in one piece because of the annular recesses on the inside. This advantage is particularly important when it comes to relatively small quantities or when the performance of the spray-lo machine can be better utilized by spraying several individual parts. Multiple division levels are also possible, particularly in the case of complicated designs. The individual parts can be connected by gluing, screwing or welding or by a combination of these methods 15. In the case of gluing and screwing, it is advantageous to design the butt joint with guide elements in order to avoid the individual parts being displaced from one another during assembly. When welding, the individual parts are prevented from moving by a corresponding holding device.

C C.

2 Blatt Zeichnungen 2 sheets of drawings

Claims

632 076 2 -

PATENT CLAIMS 10. Pipe coupling according to one of claims 7 to 9, the

1. Pipe coupling for sealingly connecting the ends of at least one pipe along the separating or dividing joint, in particular of fiber cement pipes, consisting of the edge of the tubular sleeve (1), a flange or a push-fit onto the ends of the pipes to be connected. a bar, which or which runs essentially axially, of a tubular, plastic sleeve, which has on its inner 5, this flange or bar having a circumferential direction essentially in the center of its length over the entire axial direction The length of the tubular sleeve (1) has an impact which extends from the inner circumference in the direction of, characterized in that the flange or the axis of the tubular sleeve protrudes, characterized in that the strip (9) has essentially the same radial height as the in net that this center stop (14, 15, 14a, 15a) has individual ribs (5) running the radial planes.

projections arranged at a distance from one another 10

is that on the front of the tubes to be inserted

facing flanks are chamfered.

2. Pipe coupling according to claim 1, characterized gekennzeich- The invention relates to a pipe coupling according to the net that the projections from several groups (14a, 15a) of the preamble of claim 1. Such a pipe coupling ribs, each group preferably consisting of three ' traffic jams. the DT-OS 2 503 606 known.

Ribs exist and these groups are preferably made in quarter connection of asbestos cement pipes in

circular distances over the inner circumference (1 ') of the tubular-known manner mostly by sliding over one made of asbestos

gene sleeve (1) are arranged distributed. existing coupling sleeve on both pipe ends, whereby

3. Pipe coupling according to claim 2, characterized gekennzeich- inside the coupling sleeve chambers for receiving net that each rib (14a, 15a) has a wall thickness that the 20 rubber seals are provided. These coupling sleeves of average wall thickness of the tubular sleeve (1), approximately the same, are usually manufactured in such a way that short pieces are cut from appropriately dimensioned asbestos cement pipes

4. Pipe coupling according to one of claims 1 to 3, in which in a further operation the Kam-characterized in that each rib (14,15,14a, 15a) of the core for the rubber seals are milled. The raw-raw center stop in the axial longitudinal section of a trapezoidal 25re '^ ie used to manufacture the coupling sleeves must have a profile. have an outer diameter that is much larger

5. Pipe coupling according to one of claims 1 to 4, se'n must a ^ s the outer diameter of the pipe to be connected-characterized in that it is in one piece, i.e. in particular right and material savings are provided on the specially provided - undivided in the edge areas, and is wound around an essentially hen core.

has smooth outer surface (1 "), only in 30 This type of manufacture has several disadvantages.

In the area of the ends of the pipe coupling, the inner blank that runs all the way round must be manufactured using pipes that

Chambers (3) are provided for receiving sealing rings, have a considerably greater wall thickness than the ones to be connected, possibly in the area of the chambers (3) on which the pipes are made. The production of particularly thick asbestos cement pipes with a circumferential surface (1 ") in order to maintain the same often brings difficulties to the pipe machine, wall thickness of all-round wall projections (5a) 35 also increases the specific strength of asbestos cement with sjn (j increasing wall thickness due to the nature of the Generate

6. Pipe coupling according to one of claims 1 to 5, ^ ngsprozesses from ^ In addition, its own storage and in-characterized in that it is necessary for the coupling pipes from compact injection molded maintenance of the cores.

Plastic, preferably polypropylene, is made. There? bAel f! we * ere * B ^ arbef "8 required cutting

_ _,,,,,,. 40 and milling out the blank causes a loss of material, which

7. Pipe coupling according to claim 1, characterized gekennzeich- in the waste material substantially in the form of dust, that the tubular sleeve (1) falls on its outer mantle surface, which mitvercheche only in the least amount in the production process several, m side by side, can essentially be worked. The three-stage production process, which runs over and above the level, also entails high additional costs. The entire circumference of the tubular sleeve (1) extending cutting and milling machines also require because of the ribs (5,6,7), which requires a lot of maintenance due to at least a hardness of the material.

To avoid these disadvantages, several other ribs (8) running approximately in the axial direction have already been connected to one another, in that the tubular sleeve (1) made of pipe couplings has been proposed, which is made of plastics, foamed plastics, preferably of polyolefins, film press materials or compression molding materials , in particular, and optionally at least one in an axial plane thereof is produced using a thermosetting resin reinforced with glass fibers or in a plane which is at least approximately parallel to this. In some cases, however, the separating or dividing joint (2) that is produced in the manufacture shows that these couplings are complicated and time-consuming, in some cases tubular sleeves (1) in the central zone of the distance between them are unsatisfactory from a structural point of view.

see the individual ribs running in radial planes. In the case of (5), which is known from the DT-OS mentioned at the beginning, is approximately the same as or less than its height, ^ pipe coupling is an inner one in the axial center of the coupling, and that in the axial one End zones in which on the inner circumference radially extending annular flange is provided in one piece with the sleeve (1) at least one circumferential recess (3) for jçupp {ung, which is provided as a center stop with a contact holder for sealing rings, the height of the in The ends of the two ribs (6,7) running in the coupling and the planes inserted into the coupling are smaller than that prevents. In addition, this stop secures for the tubes the ribs (5) located in the central zone. fi0 den; that the two pipes to be connected are equally far into the

8. Pipe coupling according to claim 7, characterized marked coupling are introduced.

net that the axial end faces of the pipe coupling. When laying or assembling pipe strands under bearded ribs (6,7) a greater thickness than the other (5) use of such pipe couplings occurs again and again. that it is necessary to fully fit the coupling onto a pipe

9. Pipe coupling according to claim 7 or 8, characterized to push 65 de. For this purpose, provision has so far been made many times that some of the ribs (5, 6, 7) and, in particular, those of special couplings, their manufacture and further ribs (8) running in the axial direction are low-maintenance, costly and constant Verre have radial height than the other ribs (5,6,7). Availability at the construction site is not always guaranteed.

632 076

The aim of the invention is to avoid these disadvantages.

This is achieved according to the invention in the pipe coupling described in the introduction in that this central stop is formed from individual, spaced-apart projections which are chamfered on their flanks facing the end faces of the pipes to be inserted.

By attaching individual, spaced-apart projections, these can be easily ground off with a rasp if the coupling has to be pushed over a pipe end, so that the provision of special parts is unnecessary. The bevelling of the flanks of the projections facing the end faces of the tubes to be inserted also means that the tubes are centered in the coupling. This is particularly advantageous in sewer construction, since there is a requirement for a uniform gradient across the entire wiring harness with no level differences at the joints.

According to a further embodiment of the invention, the projections can consist of several groups of ribs, each group preferably consisting of three ribs, and these groups are preferably distributed at quarter-circle intervals over the inner circumference of the tubular sleeve.

As a result, an accumulation of material which is unfavorable in terms of casting technology can be avoided at those locations distributed over the circumference of the coupling at which the projections are seated, and an optimal centering of the pipe ends can be achieved. It is particularly useful if each rib has a wall thickness that is approximately the same as the average wall thickness of the tubular sleeve. Such a configuration is particularly advantageous in terms of casting technology due to the material distribution being as uniform as possible (flow behavior of the plastic in the mold) and reduces the risk of warping of the coupling as a result of the cooling problems at the points with material accumulation and thus the occurrence of adaptation and sealing problems of the pipe ends in the coupling to a minimum.

It is also advantageous if each rib of the center stop has a trapezoidal profile in the axial longitudinal section.

In order to achieve a wall thickness that is favorable in terms of casting technology and is as uniform as possible, a particularly advantageous embodiment of the present invention is characterized in that the pipe coupling is in one piece, i.e. is undivided, especially in the edge areas, and has an essentially smooth outer jacket surface, with all-round inner chambers for receiving sealing rings being provided only in the area of the ends of the pipe coupling, where appropriate in the area of the chambers on the outer jacket surface in order to maintain the same wall thickness all around Wall projections are provided. The pipe coupling according to the invention is expediently made of compact injection molded plastic, preferably polypropylene. This enables a reduction in the wall thickness of the coupling (for example from 6 mm to 4 mm) and a corresponding saving in material and weight, and the production can be carried out in a single operation.

It has been found on the basis of tests that such a pipe coupling can also meet the static requirements mentioned at the outset which are placed on such a coupling without any problems. For extreme load cases, according to a further embodiment of the invention, the pipe coupling can be characterized in that the tubular sleeve has a plurality of ribs running in adjacent, essentially radial planes and extending essentially over the entire circumference of the tubular sleeve on its outer lateral surface are connected to one another by at least one further rib running at least approximately in the axial direction, that the tubular

Sleeve made of foamed plastic, preferably made of polyolefins, and optionally has at least one separating or dividing joint running in an axial plane or in a plane at least approximately parallel to this, that on the tubular sleeve in its central zone, the distance between the individual ribs running in radial planes is approximately equal to or less than their height, and that in the axial end zones, in which at least one circumferential recess is provided for receiving sealing rings on the inner circumference of the sleeve, the height of the radial one Flat ribs is smaller than that of the ribs located in the central zone.

These measures make it possible to optimally adapt the pipe coupling to difficult static requirements. 15 The transfer of pressure from the pipe to the pipe coupling and vice versa takes place primarily in the area of the sealing rings installed between the pipe coupling and the pipe, and therefore the area around the sealing rings is generally to be regarded as the most stressed part of the pipe coupling. 20 This part is now considerably strengthened by the measures according to the invention.

Even if foamed plastic is used as the material for this pipe coupling, it is possible to produce the pipe coupling in its final form and with an essentially smooth surface in a simple manner in a single operation, namely by non-cutting shaping, such as in particular casting or injection molding, so that any subsequent machining can be omitted. The formation of ribs on the outer circumferential surface of the pipe coupling 30 serves not only to save material, since the external shape can be optimally adapted to the actual structural requirements, but also has a significant advantage for the production. As a result of the enlargement of the surface due to the arrangement of the ribs and a simultaneous reduction in the wall thickness of the pipe coupling, the cooling of the pipe coupling after its shaping can be accelerated, so that the dwell time of the pipe coupling in the shaping tool, in particular the casting or injection mold, can be reduced 40.

This can speed up the manufacturing process.

According to a further embodiment of the invention, it is provided that the ribs adjacent to the axial end faces of the pipe coupling 45 have a greater thickness than the others. This takes into account that the ribs arranged on the edge cool down faster than the rest anyway, so that they can be made stronger without impairing the overall effect.

For manufacturing reasons, it may also be expedient for some of the ribs, and in particular the further ribs running in the axial direction, to have a lower radial height than the other ribs.

In order to improve the seal in the area of the parting plane, it is a coupling that has at least one flange or a strip on at least one edge of the tubular sleeve running along the parting or parting joint, which has a flange which extends essentially axially , wherein this flange or strip preferably extends over the entire axial length of the tubular sleeve, advantageously that the flange or strip has essentially the same radial height as the ribs running in the radial planes.