Tensionable pipe coupling

The invention relates to a stretchable tube coupling for axially connecting two smooth pipes, with shaped from a metal strip, in the connected state the tubes having end portions with at least one interruption surrounding rings radially at the inner Teeth edge lying in a plane of the metal strip have that when clamping the pipe coupling with their engage free ends into the pipe material, the one pipe associated teeth to the other Pipe associated teeth are inclined towards.

In a known pipe coupling of this type are the Teeth (also called "claw" called) saw tooth, ie in Axial direction of the pipes seen V-shaped, tapered, with their radially inner end edge obliquely to the axial direction (Longitudinal direction of the tubes) and is inclined perpendicular to the metal strip is level. The summit Although shape of the teeth has the advantage that it also at Metal pipes from entering the pipe material deep, by sliding out of the pipes from the pipe coupling to prevent at high internal pressure. Furthermore they can be given a sufficient rigidity of the tooth material with increasing internal pressure and axial movement apart the tubes from their skew towards raise the longitudinal direction radially increasingly and thereby the clamping effect of the pipe coupling the circumference of the pipes and the penetration depth of the teeth increase to the axial cohesion of the pipes despite the increasing internal pressure to ensure. But there at very high internal pressures finally the danger that the stiffness of the teeth is insufficient, in particular because of their to the pointed end decreasing cross-section, so that the teeth located in can be bent. In addition, there is the risk that the tooth tips at less hard pipes under Training V-shaped axial grooves in the surfaces the pipes axially pushing apart the tubes Allow at high internal pressure.

The invention is based on the object, a pipe coupling specify the type mentioned initially, in which the teeth do not only have a higher flexural rigidity, but also a groove formation in the pipe surface largely prevented.

This object is achieved in that teeth a transversely to the axial direction of the pipe coupling have extending edge and the outside the inserted in the pipe coupling tube facing side of each tooth to the adjacent to this side, up to the the tube remote from the tooth side provide continuous end face of the tooth an acute Angle includes.

This pipe coupling teeth are therefore, in seen axially, not tapered V-shaped. they can therefore no grooves tear in the pipe material and have a higher flexural strength near their End up. However, the end faces of the teeth can be sufficiently penetrate deeply into the pipe material, so that the Pipe connection also a very high axial load withstands.

An advantageous embodiment may consist in that the acute angle (β) in the range of approximately 50 ° to 80 °, preferably at about 70 °, and is the outer side of the the inserted in the pipe coupling tube facing side with this outside of an angle (α) in the range of about 35 ° to 55 °, preferably approximately 45 °, includes.

The invention will reference to the accompanying Drawings of preferred embodiments described in detail. Show it:<dl tsize="7"><dt>Fig. 1</dt><dd>a radial view of an embodiment the pipe coupling according to the invention, partly in section,</dd><dt>FIG. 2</dt><dd>an axial view of the tube coupling according to FIG. 1,</dd><dt>Fig. 3</dt><dd>an axial section through the pipe coupling of FIG. 1 in the tensioned state in which it two smooth pipes connecting axially,</dd><dt>Fig. 4</dt><dd>an enlarged section of FIG. 3 and </dd><dt>Fig. 5</dt><dd>a cross-section through the in Figs. 1, 3 and 4 left ring in the region represented a Tooth.</dd></dl>

The pipe coupling according to FIGS. 1 to 5 is as follows formed: A not entirely of a ring Steel curved casing 1 has at its axial ends radially inwardly bent end walls 2 whose Inner diameter greater than the outer diameter of the to connecting tubes 3 (Fig. 3). The casing 1 is in interrupted circumferential direction and to the interruption limiting ends with tabs formed, the in each case into a loop 4 (Fig. 1 and 2) to respectively an axial round pins 5 and 6 to the outside the jacket 1 bent around and on this by projection welding 7 (FIG. 1) are attached. The loops 4 each have a part of them are the round bolt 5, 6 around extending slot 8 (Fig. 1). The round bolt 6 has in the region of the slots 8 each an axially through hole without internal thread. The round bolt 5 has in the region of each slot of the other loop also a radially continuous hole, but with Internal thread. The slots 8 and the radial bores the round bolt 5, 6 are each of a clamping screw 9 interspersed whose head 10 has a polygonal socket and on a shoulder 11 of the through holes the round bolt 6 widening blind hole is present.

On the inner side of the bending edge of the end walls 2 of the Jacket 1, the radially outer edge is in each case a frustoconical, once interrupted in the circumferential direction Ring 12 at. The rings 12 are made of a metal band shaped. At its radially inner edge, the Rings 12 lying in the plane of the metal strip, in Axial direction of the tubes 3 seen approximately trapezoidal Teeth 13 provided. The end portions 14 (Fig. 2) of each Ring 12 overlap in the circumferential direction.

On the inside of the shell 1 is located a gasket 15 of elastomeric material with an angle radially inwardly at each axial end projecting sealing lips 16, 17 at. The sealing lips 16, 17 are located at the Tubes 3 to the outside when the tubes 3 as shown in FIG. 3 in the are inserted and braced pipe coupling. In between the sealing lips 16 is located on the inner side of the sealing sleeve 15 a molded from a sheet metal strip Ring 18, who once interrupted in the circumferential direction and whose end portions in the circumferential direction overlap. The ring 18 ensures that the material the sealing sleeve 15 during tightening of the pipe coupling is not pushed between the ends of the tubes. 3

The interruption of the shell 1 is by a bridge bridged at the periphery of the sealing collar 15 is applied and overlapped by the end sections of the jacket 1 is.

As FIG. 3 shows, the one tube allocated Teeth 13, including the ring 12, on which it is formed are, to the other tube 3 associated Teeth 13, including the other ring to which this Teeth 13 are formed at an angle of α about 35 ° to about 55 °, preferably 45 °, as shown in FIGS. 4 and 5 are inclined towards. The outside of the Pipe coupling inserted pipe 3 facing side 19 of each tooth 13 includes with the end face 20 of the free tooth end an angle β of about 50 ° to about 80 °, preferably about 70 °, a (Fig. 5). This results a sharp edge 21 on each tooth end, the transversely to the axial direction of the pipe coupling and the Pipes 3 extends.

When clamping the pipe coupling the teeth 13 penetrate with the sharp edges 21 at their free ends in the A pipe material, cf. Figs. 3 and 4, and thereby prevent, in conjunction with the over a longer Piece in the circumferential direction of the tubes extending edges 21, a pulling apart the pipes 3 at high internal pressure in the tubes 3. The pipe in the circumferential direction due its trapezoidal shape slightly wider than V-shaped teeth formed teeth 13 also have a higher bending stiffness. In addition, the rings have 12, including the teeth 13, the effort to sit up radially, when the tubes 3 under the internal pressure want to move apart axially. This increases the penetration depth of the teeth 13 in the tubing and therefore the axial load carrying capacity of the pipe coupling resulted in connection of the tubes.

Accordingly, the pipe joint holds very high Axial loads, which tend to move pipes apart, without bending the teeth 13 and without the formation of axial grooves in the tubes 3 stood by the teeth. 1

Modifications of the illustrated embodiment may consist, for example, that the end walls 2 of the shell 1 is not exactly radially, but axially toward each bent and with the teeth 13 of the Rings be provided 12 corresponding teeth in the can engage tubing. Optionally, the rings 12 omitted so that only the end walls 2 form respective rings. It would also be possible, the rings 12 additionally provide.

Alternatively, with on the inside of the jacket 1 mounted a double row of teeth provided rings be, the teeth of each ring in the same Direction or in opposite directions Longitudinally be inclined.

For metal pipes, the material of the rings would from Sheet steel. For pipes made of softer material, such as plastic, the rings may also be made less hard Sheet metal made.