WO1982003440A1

WO1982003440A1 - Sealed coupling of plastic material pipes resisting to thrust forces

Info

Publication number: WO1982003440A1
Application number: PCT/DE1982/000072
Authority: WO
Inventors: Georg Seiler
Original assignee: Georg Seiler
Priority date: 1981-03-30
Filing date: 1982-03-29
Publication date: 1982-10-14
Also published as: IT8220474A0; IT1190749B; EP0076275A1

Abstract

For a reliable clamping of connections of plastic material pipes (101) against axial forces, rolling members (24, 35) having peripheral asperities (25) are housed in a sealing joint (13, 23). Without biting exaggeratedly in the sections of the pipe, these members do not allow practically any deformation of engaged extremities (1, 107) at the connection point. A sleeve (110) is housed inside the male extremity (1, 102) and a ring (114) covers the projecting portion (7) of the sleeve containing the joint (13, 23).

Description

Sealed and secured against thrust sleeve connection on plastic pipes

The invention relates to a sealed and secured against shear forces socket connection on plastic tubes, in which a smooth cylindrical insertion end is accommodated with little play in a socket end, in which a Uraffang bead open to the tube axis is provided with an approximately triangular cross-section, in which a cross-section approximately wedge-shaped sealing ring with a plurality of clamping elements distributed in the circumferential direction and embedded in the sealing material can be inserted.

A combined sealing and thrust locking ring of this type is known from DE-OS 28 54 868. In this case, a plurality of clamping pieces made of plastic arranged in the circumferential direction at larger intervals are provided as clamping elements, which have on their part-cylindrical inner surface a solid coating of grains which consist of a material which is harder than the plastic of the clamping pieces and the tubes and the tubular molded body. The clamping pieces can have a circumferential bore through which a cord-like support element for the clamping pieces can be inserted or the material of the sealing element can be pressed into the bore in a cord-like manner through bore extensions. The manufacture of the clamping pieces is relatively complex and leads to relatively high costs, which cannot always be tolerated in the case of a mass article. The clamping pieces, which are relatively large in volume, also require a sufficiently wide one. Circumferential distance to enable the clamping pieces to be securely embedded in the sealing ring. It can be seen that when plastic pipes (PVC) are clamped for longer periods of time under pressure, the material of the plastic pipes flows coldly into the spaces between adjacent clamping pieces, which gradually diminishes the clamping effect. The inner circumferential surface of the clamping pieces must also be machined relatively precisely if the surface of the grains is to be sufficiently used.

It is an object of the invention to further develop and simplify and reduce the cost of the known thrust protection and at the same time to ensure better clamping of the smooth titanium end of the pipe connection.

This object is achieved according to the invention in that a ring of rolling elements which are arranged essentially close to one another in the circumferential direction are embedded as clamping elements in the combined sealing and thrust securing ring. If a sealing ring is assumed, the circumference of which facing the pipe axis consists of two cross-sectional areas delimited in a partial circle in the axial direction, the ring of rolling elements is preferably arranged relative to the cross-sectional area delimited further axially on the outside in such a way that the pitch circle circumferences of this cross-sectional area of the sealing ring and substantially align the rolling elements in the circumferential direction.

The volume of the rolling elements, which can consist of metal or plastic, is small compared to the known clamping pieces, so that the volume of the seal ring can perform the sealing function much better. The small cross-sectional area of the rolling elements enables a substantially more favorable arrangement of these rolling elements, both within the cross-section of the sealing ring and in the circumferential direction, in which the rolling elements can be embedded practically close to one another in the sealing ring. This ensures that the gaps between successive circumferential surfaces of the rolling elements, which engage the insertion end of the tube, are extremely small, so that the material of the tubes cannot flow coldly in the clamping area. As a result, the clamping effect is maintained essentially unchanged even over long service lives. Despite the tight circumferential arrangement of the rolling elements, the combined sealing and thrust locking ring is sufficiently flexible to be easily inserted into the circumferential bead of the sleeve end. The circumferential surface of the rolling elements is roughened, in particular provided with a knurling which is designed in such a way that a notch effect at the insertion end cannot occur to the extent that there is a risk of damage, even under increased pressure.

The combined sealing and thrust retaining ring is dimensioned by nature so that it is inserted under pre-tension and is expanded by the smooth insertion end when the insertion end is inserted into the sleeve.

The rolling elements can be manufactured extremely cheaply and easily, and the preferred conical design of the end face can be produced directly when the individual rolling elements are tapped off from a correspondingly profiled rod material. The rod material can have a longitudinal borehole from the outset, so that the rolling elements can also be threaded onto a cord-like supporting element if necessary. Due to the design of the clamping elements in the form of rolling elements, these can be arranged at a particularly favorable location on a profiled sealing ring.

The socket connection can also be developed in such a way that the thrust protection is retained to the full extent even over long standing times, without it being necessary to make the pipes in the connection area stronger, i.e. to train with greater wall thickness. For this purpose, in the area of engagement of the clamping elements embedded in the sealing ring, the plug-in end on its inside and the sleeve end on its outside can each be surrounded by a sleeve made of a dimensionally stable material of low cold flow capacity. These cuffs only have the task of the cold flow effort of the plastic material. To limit plastic pipes in the connection area, so that in the engagement area of the clamping elements. The shape and dimensions of the corresponding areas of the plastic pipes practically do not change.

It must be taken into account here that the invention concerns the shear protection on plastic tubes, which are much more sensitive to the notch effect and also show the special properties of the cold flow deformation of the tube material.

The invention is explained in more detail below with the aid of schematic drawings using several exemplary embodiments.

Show it:

1 shows a detail of a longitudinal section through one side of a pipe socket connection of the type in question. Figure 2 shows a cross section through the sealing ring preferably used.

Figure 3 on a larger scale the combined sealing and thrust retaining ring.

Figure 4 is a side view of an embodiment of the ring of rolling elements.

Figure 5 in a similar representation, a modified embodiment of the rolling element and

FIG. 6 shows a detail of a cross section through a reinforced sleeve connection according to the invention,

Figure 1 shows the socket connection between a smooth insertion end 1 and the socket end 3 of plastic tubes. The sleeve end 3 has a cylindrical extension 5, which is followed by a radially inwardly open bead 7 of essentially triangular cross section. The bead has a steeper, shorter triangle leg 8 and a flat, inclined, longer leg 11. The individual sections are connected to one another via radii of curvature 9, 10 and 12. A short cylindrical end section 6 adjoins the bead, which is essentially aligned with the cylindrical section 5. The free end edge 2 of the insertion end .1 lies opposite the inner shoulder 4 of the socket end at a short distance. The clear width of the pipes is indicated with "D".

A sealing ring is inserted into the bead. A sealing ring with the cross section as shown at 13 in FIG. 2 is preferred. The substantially wedge-shaped sealing ring has an upper, thicker section 14 of a partially circular outline. The center point "A" falls with the center of curvature of the radius 12 of the bead together, the radius of curvature 15 of the section 14 of the sealing ring being equal to or slightly larger than the radius of curvature 12. A particularly effective sealing lip is formed by a circumferential groove 16 in the area of the largest radial dimension of the bead. Section 14 is followed by a second region 17 of seal 13, which also has a part-circular outline. On the radially outward-facing side, the sealing ring 13 is delimited by a truncated cone surface 18.

In this sealing ring according to FIG. 2, a ring of essentially tightly lying rolling bodies 24, which are shown in FIGS. 3 and 4, is embedded. It can be seen that the rolling elements 24 are dimensioned and embedded in the cross section of the sealing ring in such a way that the pitch circle circumferences. of the axially outer region 17 of the sealing ring 13 and partial circular circumferential regions of the rolling bodies 24 are essentially aligned in the circumferential direction, as can be seen from FIG. 3.

The circumference of the rolling bodies 24 is preferably roughened, for example provided with knurling 25 following the surface lines. The rolling elements can also have a central bore 26 into which a cord-like support element 27 e.g. is threaded out of rubber. The frustoconical surface 18 is expediently in the region of the ring from. Rollers 24 withdrawn to the axis of the pipe connection, as indicated in Fig. 3 at 18a.

In FIG. 3, the outline of the bead is also indicated by dash-dotted lines through the boundary lines 21 and 22 of the insertion end and the socket end. The end faces of the individual rolling bodies 24 are expediently frustoconical, as shown at 26a. In order to The rolling elements can be practically close to one another, at least in the relaxed state of the sealing ring 13 or 23. The widening when the insertion end 1 is inserted can result in small irregular distances between adjacent rolling elements, as is indicated at 30 and 31 in FIG. 4 .

The rolling bodies 35 can also be machined on their end faces in such a way that on one side there is a truncated cone surface 37 and on the other end face an undercut conical surface 36. The end machining of the rolling elements takes place immediately when the rolling elements are cut off from a correspondingly profiled bar material. Post-processing is not necessary. The rolling elements can be made of plastic or metal.

When embedding the rolling elements in the material of the sealing ring, care should be taken that the distance between adjacent rolling elements corresponds at most to approximately the thickness of the wall of the plastic tube.

The bar material, from which the rolling elements are separated, is bent beforehand, preferably approximately according to a circular arc with a diameter approximately equal to the diameter of the plastic pipes.

The socket connection 101 shown in FIG. 6 corresponds to that of FIG. 1. The following are designated: the smooth pipe end with 102, the socket end with 104, the rounded end face with 103, the groove open towards the pipe center with 105, the leg with 106 and 107 and the curvature section connecting them with 109. The largest diameter of the sleeve is indicated with 115. In order to prevent any change in shape of the groove 115 in the engagement area 112 of the clamping elements (cf. FIG. 3) in the socket connection, a sleeve 110 is drawn in inside the insertion end 102, which consists of a creep-resistant and metal-containing material, in particular metal. In the front area 103 of the insertion end 102, the sleeve can be slightly widened, as indicated at 113, but the rounding of the end face 103 should be impaired and influenced as little as possible.

A bushing 114 made of creep-resistant and shape-retaining material is drawn onto the bead-shaped area of the sleeve end. This also preferably consists of metal. It predominantly covers the longer, flatter leg 107 of the corrugation and extends to the area of the largest diameter 115 of the corrugation. Both cuff-like bodies are firmly drawn in or drawn onto the surfaces in question with as little play as possible or shrunk on by the action of heat. Corresponding adhesives can also be used to increase the connection. It is essential that the relevant wall sections of the pipe connection are firmly clamped by the sleeves. In order to secure the socket 114 even better in its position, it can have tongues 116 protruding from its free wide end, which converge towards the tube axis and snap over the area of the largest diameter 115 of the bead.

Claims

Expectations

1. Sealed and secured against shear forces socket connection on plastic pipes, in which a smooth cylindrical insertion end is accommodated with little play in a socket end, in which a circumferential bead open to the pipe axis is provided with an approximately triangular cross-section, in which a combined cross-section approximately wedge-shaped Sealing and thrust securing ring with a plurality of clamping elements distributed in the circumferential direction and embedded in the sealing material can be inserted, characterized in that a ring of rolling elements (24) with a roughened or knurled circumferential surface (25) which is arranged essentially close to one another in the circumferential direction is embedded in the sealing ring .

2. Socket connection according to claim 1, characterized geken nz calibrates that in a sealing ring whose circumference facing the tube axis consists of two consecutive axially delimiting cross-sectional areas (14, 17), the ring of rolling elements (25) to the axially further outside horizontal cross-sectional area (17) is arranged in such a way that partial circle circumferences of this sealing cross-sectional area (17) and the rolling elements (24) are substantially aligned in the circumferential direction.

3. Socket connection according to claim 1, characterized in that the rolling elements (24) threaded onto a cord-like supporting part (27) are frustoconical on their end faces (26, 36, 37).

4. Socket connection according to claim 1, characterized in that a transverse knurling (25) is provided on the circumference, running parallel to the surface lines of the roller-shaped rolling bodies.

5. Socket connection according to claim 1, characterized in that the radially outwardly facing, cone-shaped peripheral surface (18) of the sealing ring (13) in the region of the ring of rolling elements (24) is withdrawn radially inwards relative to the peripheral region of the rolling elements lying in this surface (18a).

6. Socket connection according to claim 1, characterized in that the rolling bodies are sections of a rod or tube material bent approximately according to the circumferential curvature of the plastic tube.

7. Socket connection according to claim 1, characterized in that the mutual spacing of the embedded rolling elements corresponds at most to approximately the wall thickness of the plastic pipes.

8. Socket connection according to claim 1, characterized in that in the engagement area (112) of the clamping elements embedded in the sealing ring (118, 121), in particular rolling element (119, 122), the insertion end (102) on its inside and the sleeve end (104) on its outside in each case are enclosed by a sleeve (110) or (114) made of a dimensionally stable material of low cold flow capacity.

9. Socket connection according to claim 8, characterized in that a metal sleeve (110) is drawn into the insertion end (102).

10. Socket connection according to claim 9, characterized in that the outer end (113) of the metal sleeve (110) is slightly widened in the region of the end face (103) of the insertion end (102).

11. Socket connection according to claim 8, characterized in that a metal cone (114) which widens in the shape of a truncated cone is drawn onto the sleeve end (104).

12. Socket connection according to claim 11, characterized in that the metal bushing (114) ends with its largest width approximately in the region (109) of the largest diameter (115) of the sleeve end (104).

13. Socket connection according to claim 12, characterized in that the metal bushing (114) has, from its wide end, projecting clip-like tongues (116) which converge in the direction of the pipe axis.