DE3116803A1 - Sealed spigot-and-socket joint, secured against shear forces, on plastic pipes - Google Patents

Abstract

In order to prevent a change in shape of the interengaging portions of a plastic pipe connection by cold creep of the material or the like and to achieve better absorption of the radial forces exerted by clamping elements in a sealing ring, a sleeve (110), in particular in the form of a metal sleeve, is drawn, according to Figure 1, inside into the plug-in end (102), and an expanding sleeve (114) is drawn onto the part of the sleeve delimiting the bead (105) receiving the seal. The two sleeves enclose the relevant pipe portion in the contact region (112) of the clamping elements and thus prevent migration of the material owing to the action of the clamping forces caused by cold creep, and thus also prevent a reduction in the clamping force. <IMAGE>

Description

Sealed and secured against shear forces

Socket connection on plastic pipes The invention relates to a Sealed socket connection on plastic pipes secured against shear forces, where a smooth cylindrical spigot end with little play in a socket end is added, in which a circumferential bead open towards the pipe axis with an approximately triangular cross-section is provided, in which an approximately wedge-shaped cross-section Sealing ring with several distributed in the circumferential direction and in the sealing material embedded clamping elements can be inserted.

Such socket connections are known (see e.g. DE-OS 28 54 868). To better fit the clamping elements to the circumference of the pipes to achieve and the space between adjacent clamping elements in the circumferential direction It has also already been proposed to reduce the size of those known from DE-OS 28 54 868 wedge-shaped clamping pieces by essentially closely arranged rolling bodies to be replaced with a roughened or knurled peripheral surface. In both cases the clamping elements are embedded in the sealing ring.

Both connections give a good seal and also a good one Protection against axially acting shear forces. However, difficulties can arise the special properties of plastics occur over longer service lives change their shape in a cold way by creeping the material. Here is the There is a risk that, due to the creep of the material, the force exerted by the clamping elements and the shear forces absorbing clamping forces gradually decrease, so that the desired Securing the connection against shear forces is no longer guaranteed.

It is the object of the present invention to provide a socket connection of To be further developed, as described in more detail at the beginning, so that even over a long service life the thrust protection is retained in full without it being necessary to make the pipes stronger in the connection area, i.e. with a greater wall thickness.

This object is achieved according to the invention in that in the attack area of the clamping elements embedded in the sealing ring, the insertion end on its inside and the socket end on its outside by a sleeve of a dimensionally stable material of low cold flow capacity are bordered. These cuffs only have the task of the cold flow tendency of the plastic material of the plastic pipes to limit dimensionally stable in the connection area, so that in the area of attack the Clamping elements the shape and dimensions of the corresponding areas of the plastic pipes practically does not change. Only then is it reliably achieved that too at the clamping force required to absorb the shear forces for a longer service life the clamping elements in the connection area remain unchanged. This effect is particularly favorable when using rolling elements as clamping elements.

A metal sleeve or a sheet metal tube is preferred in the insertion end drawn in, the material and wall thickness of which are such that the metal sleeve any evasion of the plastic material by cold creeping radially inward resistance perform. In order to be able to guarantee a secure position of the metal sleeve in the insertion end the free end of the metal sleeve in the area of the end face of the insertion end is weak be widened, but without the rounding of the tube face provided at this end to change or impair.

A truncated cone is expediently formed on the socket end widening metal bushing or sheet metal bushing, which have the same requirements for the socket end, like the metal sleeve for the spigot end, with the difference that the metal bushing is exposed by material creep of the Has to prevent the area of the socket end in which the sealing and shear locking ring receiving bead is arranged. To secure the metal bushing on the socket end, may have tongues protruding from the end of the largest diameter of the metal bushing be provided which converge in the direction of the pipe axis. The metal sleeve and the metal bushes are tightened or pulled in as tightly as possible on a cold or warm path, to ensure a firm clamping. Any changes to the pipes are not required for this.

The invention is based on schematic drawings an exemplary embodiment explained in more detail.

The figures show: FIG. 1, in a detail, a cross section through the socket connection according to the invention and FIGS. 2 and 3, two different exemplary embodiments each in cross section for the sealing and locking ring that can be used in connection with the socket connection.

The socket connection 101 shown in FIG. 1 corresponds to that for such Plastic pipes widely used connection. The smooth pipe end 102 is very added slight play from the socket end 104 of the adjacent pipe, wherein between the rounded end face 103 of the insertion end 102 and the corresponding Shoulder of the socket end 104 remains a corresponding gap. The socket end points a bead-shaped section which has a groove 105 open towards the pipe axis forms a substantially triangular cross-section.

The groove is created by a short, steeper leg on the inside 106 and a flatter, outer leg 107 limited, both legs are connected to one another by a curved portion 109. The largest diameter the socket is indicated as 115.

A sealing ring 117 or a sealing ring is inserted into the bead 105 120 inserted. Each sealing ring has clamping elements distributed in the circumferential direction Rich on. In the sealing ring 117 are in the rubber compound 118 of the sealing ring in essentially tightly packed rolling elements 119 with a roughened or knurled one Embedded peripheral surface. In the case of the sealing ring 120, the rubber mat 121 wedge-shaped clamping pieces 122 embedded, the inner surface of which is partially cylindrical and appropriately roughened. To in the engagement area of the clamping elements 119 or 121 in the socket connection, which engagement area is indicated by 112 is to prevent any change in shape of the groove 115 is inside the male end 102 a sleeve 110 is drawn in, which is made of a creep-resistant and shape-retaining material, especially made of metal.

In the frontal area 103 of the insertion end 102, the sleeve be slightly widened, as indicated at 113, but with the Rounding of the end face 103 should be impaired and influenced as little as possible target.

A bushing is made on the bead-shaped area of the socket end creep-resistant and shape-retaining material, which is designated by 114. Even this is preferably made of metal.

It mainly covers the longer, flatter leg 107 of the bead and extends to the area of the largest diameter 115 of the bead. Both cuff-like Bodies are firmly attached to the surfaces concerned with as little play as possible. or pulled up or shrunk on by the action of heat.

Appropriate glue can also be used to increase the connection used will. It is essential that the relevant wall sections of the pipe connection through the cuffs are firmly clamped. To the socket 114 in its position even better to secure it can have tongues 116 projecting from its free, wide end, which converge to the pipe axis and over the area of the largest diameter 115 grab the bead like a snap.

The connection in connection with the sealing ring is preferred used according to Fig. 2, in which the rolling body lying essentially close together the creeping of the plastic material in the side facing away from the sleeves additionally restrict.

Claims (6)

Claims 0 Sealed socket connection secured against shear forces on plastic pipes, for which a cylindrical spigot end with a low Game is added in a socket end, in which an open to the pipe axis Circumferential bead is provided with an approximately triangular cross-section into which a in cross section approximately wedge-shaped profiled sealing ring with several in the circumferential direction distributed and embedded in the sealing material clamping elements, especially in the form of substantially closely arranged rolling elements with roughened or knurled circumferential surface, is inserted, thus g e k e n n n -z e i c h n e t, that in the engagement area (112) of the clamping elements embedded in the sealing ring (118,121), esp. Rolling body (119, 122) the insertion end (102) on its inside and the Sleeve end (104) on its outside by a sleeve <11o) or (114) made of a dimensionally stable material of low cold flow capacity are. 2. socket connection according to claim 1, characterized in that g e k e n nz e i c h n e t that a metal sleeve (110) is drawn into the insertion end (102). 3. socket connection according to claim 2. characterized g e k e n n - z e i c h n e t that the outer end (113) of the metal sleeve (110) in the area of the end face (103) of the spigot end <102) L is slightly widened. 4. socket connection according to one or more of claims 1 to 3, in that it is frustoconical on the socket end (104) expanding metal bushing (114) is pulled up. 5. socket connection according to claim 4, characterized in that g e k e n n -z e i c h n e t that the metal bushing (114) with its largest width approximately in the area (109) the largest diameter (115) of the socket end (104) ends. 6. socket connection according to claim 5, characterized in that g e k e n n -z e i c It should be noted that the metal bushing (114) protrudes from its wide end like a bracket Has tongues (116) which converge towards the axis of the pipe.