Coupling assembly

(42) Date of commencement of the patent: 15.12.1991 (45) Date of issue: 10. 7.1992

<td>(30) Priority:</td><td>(73) Patent owner:</td>

<td>2. 8.1986 DE 3626289 claimed.</td><td>RASMUSSEN GMBH</td>

<td>22. 9.1986 DE 3632127 claims.</td><td>D-6457 MAINTAL (DE).</td>

<td>(56) Documents:</td><td>(72) Inventor:</td>

<td>DE-AS2039607 US-PS3756629</td><td>ZEIDLER SIEGMUND ING. HANAU (DE).</td>

(54) PIPE COUPLING (57) In a pipe coupling with a tensionable clamp (3) for receiving smooth pipes to be connected (1, 2) or a pipe to be coupled with a stationary object and with at least two securing devices (5, 6) in at least one radially inwardly open chamber (17, 19) of the clamp (3) are arranged and have on the chamber walls (20,21,22,23) fitting safety elements, is ensured for ease of mounting the safety devices (5,6) and higher axial load capacity of the pipe coupling, in that the securing elements (5, 6) have side walls (28) extending in the tube circumferential direction and axially up to the support on lateral chamber walls (20, 21, 22, 23), which are provided at their radially inner edges with claws (29), in that the steepness of the side walls (28) of the securing elements in relation to the tube longitudinal direction is less than that of the inner surfaces (25) of the side walls (20, 21, 22, 23) of the chamber (17, 19), and that the securing elements of each securing device (5,6) are interconnected.

<img file="AT394896B_D0001.tif" />

968 P6 £ IV

HR 0078918

AT394 896B

The invention relates to a pipe coupling with a tensionable clamp for receiving smooth end sections to be connected to two pipes or a pipe to be coupled with a stationary object and having at least two safety devices, which are arranged in at least one radially inwardly open chamber of the clamp and have fitting elements on the chamber walls, which are provided with claws for the radial engagement in the tube material and distributed in the tube circumferential direction.

In a known pipe coupling according to the US-PS 1930 194, the securing means are formed by about three circular segment-shaped securing elements which are pivotally mounted about an axis lying in an axial plane of the tubes transverse axis. The securing elements are provided on a concentric with its axis of rotation circumference with the claws forming teeth, which engage in the pipes to be joined. Because of the concentric position of the teeth to the axis of rotation, the securing elements are only rotated when the tubes are pulled apart, wherein they can only be pivoted to a side wall of the individual receiving chambers. At this stop formed by the side wall, they continue to engage with their teeth in the pipes, preventing further pulling apart of the pipes.

In another known pipe coupling according to the US-PS 2,005,056, the securing elements are approximately cylindrical in shape, wherein the rollers extend in the axial or circumferential direction of the tubes and are provided at its periphery with teeth which engage in the pipe material. For each securing element, a separate chamber is provided in the clamp shell whose circumferentially extending side walls limit movement of the rollers in the axial direction of the tubes.

Then, a pipe coupling with safety devices in DE-PS 24 28 101 is to be taken as known, which is in each case designed as a circulating on the inside of the clamp, in the side view approximately truncated conical anchoring ring. In its smaller diameter peripheral edge of the anchoring ring is provided with axial slots, wherein the slats lying between the slots overlap each other in the circumferential direction and form the engaging in the pipe material claws. As the tubes connected by the pipe coupling are subjected to axial tensile loading and thereby pulled apart, the conical portion of the anchoring rings radially aligns with respect to the tubes so that the clamp presses the anchoring rings against the tubes with greater force and further disengagement of the tubes is prevented. For erecting the anchoring rings, however, a bending of the ring material over the entire circumference is required, so that a high bending moment to overcome, which counteracts the erection of the anchoring rings. Before erecting the anchoring rings and the

Increasing the clamping force by the erection can therefore have already been caused by the claws by a considerable axial relative displacement of the two pipe ends with removal of the pipe material. Only when finally by the axial displacement has resulted in a larger accumulation of pipe material in front of the claws, the Aufrichteffekt is effective.

The invention has for its object to provide a pipe coupling of the generic type, which allows for easier mountability of the safety devices a higher axial load of the pipe coupling without the pipe ends move appreciably relative to each other.

According to the invention, this object is achieved in that the securing elements extending in the tube circumferential direction and axially to the support on lateral chamber walls have diverging side walls which are provided at their radially inner edges with claws, that the steepness of the side walls of the

Fuse elements based on the tube longitudinal direction is less than that of the inner surfaces of the side walls of the chamber and that the securing elements of each securing device are interconnected.

In this solution, the joining of the joint between the end portions of the tubes facing side walls of the fuse elements when pulling the pipe ends can raise almost immediately and increase by raising the impressing the claws in the pipe material causing radial force. Even with respect to axial forces, which endeavor to press the pipe ends against each other, the safety device offers higher resistance. The inclusion of such Axialschub- or compressive forces is particularly desirable if the clamp still includes a sealing sleeve, which is provided on its radially inner side with a circumferential, engaging between the end faces of the pipe ends to be connected rib. If necessary, this rib is not damaged by excessive thrust forces. The high Axial50 compressive load is also desirable when the pipe coupling is to be used as a stationary pipe holder, which serves as a fixed point against which a displacement of the tubes due to thermal axial expansion should be avoided. In this case, the pipe coupling surrounds only one pipe, which connects them with a stationary object (building wall or the like), without a sealing sleeve between the clamp and pipe would be required. The lateral support of the securing elements through the chamber walls ensures that the supported side walls of the securing elements do not spread so far under the radial pressure of the clamp that they would disengage from the tube material. Rather, the radial clamping pressure is conducted almost completely radially into the claws at least the supported side walls of the securing elements, so that the claws firmly dig into the tube material, although the inclination of the side walls of the securing elements is relatively low, so that they can withstand high axial forces.

Preferably, it is ensured that each securing device is arranged in a separate annular chamber.

The formation of the hitherto separate, lying on a perimeter chambers as a (continuous)

Ring chamber, one of which is provided for each securing device, not only facilitates the production

-2AT394 896 B of the chambers, but also the installation of the safety devices and, where appropriate, their fixation in the clamp, since a plurality of fuse elements of a safety device can be mounted at once. Furthermore, the securing elements are laterally supported by the sidewalls of the annular chambers on their two side walls.

Preferably, the axial cross section of each annular chamber and the securing elements is approximately trapezoidal. The inner surfaces of the side walls of the annular chambers therefore run obliquely and additionally exert a radial pressure on the free ends of the side walls of the securing elements against them when the clamp is tensioned. Furthermore, the trapezoidal shape causes an axial centering of the securing elements in the annular chambers.

Then it can be ensured that the one or more securing elements of each securing device are integrally connected. This one-piece connection of the securing elements simplifies their assembly and improves their cohesion

Preferably, care is also taken that preferably each safety device is stamped from a flat spring steel sheet metal strip, in that the metal strip has, at its longitudinal edges, preferably sawtooth-shaped claws lying on circular arcs with a radius of curvature approximately corresponding to the outer radius of the pipe, and diverging indentations delimiting the side walls of the securing elements in its longitudinal edges, and that the stamped sheet metal strip, bending the sidewalls, is shaped into a circular arc. Such a security device can be produced in a simple manner from a single sheet metal strip.

Hiebei it can be ensured that a burr arising during punching lies on the radially inner side of each securing device. This ridge is relatively sharp and facilitates the impressions of the claws in the pipe material. The ridge opposite cutting edge of the same cutting surface is rounded slightly at the same time during punching and applies during spreading of the side walls of the securing elements during clamping of the clamp only on the side wall facing the respective annular chamber, without penetrating into the material of the side wall of the annular chamber. The clamping force flow passing through the side walls of the securing elements is therefore deflected better in the radial direction toward the tube.

An even better rounding of that cutting edge results when the longitudinal edges of the sheet metal strip are pre-rounded before punching on their side facing the punching tool.

The slope of the side walls of the fuse elements is approximately 0.36 to 0.58, preferably 0.47. In this area, there is a particularly high level of security against axial displacement of the tubes within the clamp.

Preferably, the diameter of the incircle of the claw tips is smaller than the inner diameter of the chamber walls. In this way it is ensured that only the claw tips engage in the pipe material before the chamber walls create the pipe circumference. Preferably, however, always remains at least a slight distance between the chamber walls and the tube circumference.

Then it can be ensured that the safety devices are pressed with the clamp enforcing clamping screws against the pipes or pipe. In this way, the Verkrallungseffekt can be significantly increased.

If the securing devices are supported on one side by the lateral chamber walls on the pipe surface, the clamp jacket needs to be provided with a total of only two chamber walls, d. H. show only one ring chamber. Nevertheless, there is a sufficient axial load capacity caused by the pipe coupling connection, as has been shown in practice, since the claws lying on the supported side of the securing device in each case penetrate sufficiently deep into the pipe material due to the axial support by the adjoining chamber wall during clamping of the clamp, as long as this support is ensured for example, by that also the claws of the other side walls penetrate radially into the raw material, if only slightly.

Preferably, only side walls of the securing devices facing away from each other are supported by one of the chamber walls. Hiebei are the support causing chamber walls on the axially outer side of the securing devices, so that these chamber walls formed at the axial ends of the clamp and thus the clamp body can be easily bent from sheet metal.

Ensuring the lateral support of the safety devices can be further improved by the fact that the safety devices are attached to the clamp, z. B. with screws, rivets or spot welds.

Furthermore, it can be ensured that the angle of inclination of the free side walls of the securing means relative to the axis of the clamp is greater than the inclination angle of the supported by the chamber walls side walls of the securing devices. The non-supported side walls of the safety devices are in this training to a greater extent endeavors to raise in a radial plane when the pipe joint is loaded by axial tensile forces. They then provide a greater degree of jamming of the clamp on the pipes and thus for a higher axial tensile load capacity.

The invention and its developments are described below with reference to the drawing of preferred embodiments. Show: 1 a perspective view of a pipe coupling according to the invention for connecting the ends of two tubes, partially in section, Fig. 2 a perspective view of a portion of a securing device of the pipe coupling of FIG. 1, Fig. 3 a plan view of a portion of an angled securing device of the pipe coupling of FIG. 1, Fig. 4 the circular section of Fig. 1

5 shows a perspective view of a modified pipe coupling according to the invention for connecting the ends of two pipes, partly in section, and FIG. 6 shows a part of the pipe coupling according to the invention according to FIG. 5 with a somewhat bent protective device.

The pipe coupling of FIG. 1 serves to connect the ends of two coaxial tubes (1) and (2) whose diameter and wall thickness are substantially identical. The pipe coupling consists of a two-part clamp (3), an annular sealing sleeve (4), schematically illustrated as a dotted line clamping screws (7) and (8) with Muttem, which are guided through bores (9) and (10) in axial flanges (11) and (12) of each clamp half (13) and (14), and clamping screws (15) and (16), which are screwed through threaded holes of the clamp shell up against the securing devices (5) and (6), if necessary in addition to the clamping force of the clamp (3) to press against the outer sides of the tubes (1) and (2).

The clamping screws (15) are associated with the securing device (5) and the clamping screws (16) of the securing device (6) and distributed in each case over the circumference of the clamp (3).

The clamp (3) has on its inside circumferential annular chambers (17,18 and 19), which are interrupted only in the area between the flanges (11) and (12) of the clamp halves (13) and (14) lying column. The annular chambers (17) and (19) located at the axially outer ends of the clamp (3) each contain one of the securing devices (5, 6) and are bounded by side walls (20, 21, 22) and (23), of which the Axial outer side walls (20) and (23) radially inwardly projecting flanges and the middle side walls (21) and (22) form radially inwardly projecting ribs.

The axial cross section of the annular spaces (17,18) and (19) is approximately trapezoidal, wherein the annular surfaces (17) and (19) delimiting inner surfaces (25) of the side walls (20) to (23) has a relatively large angle of inclination (ßp compared to Have tube longitudinal direction, as shown more clearly in Fig. 4

The elastomeric plastic existing sealing sleeve (4) projects with a circumferential on the axial center of its inner rib (26) in the gap between the facing end faces of the pipes to be joined (1) and (2) and surrounds the rest of the other end portions of the tubes (1) and (2) within the annular chamber (18). The sealing sleeve (4) can in turn be surrounded within the annular chamber (18) by a not shown tensionable clamp with radially inwardly projecting end flanges, the closure of this additional clamp is accessible through a recess in the shell of the clamp (3) from the outside.

The safety devices (5) and (6) consist of approximately trapezoidal in cross-section, on a circular arc corresponding to the curvature of the annular spaces (17) and (19) lying securing elements (27) whose side walls (28) with the tube longitudinal direction a smaller angle of inclination ( ß₂) as the inner surfaces (25). The angle of inclination (ß₂) may be in the range of about 20 ° to 30 °, and is preferably 25 °, which is a steepness (tanβ2) of the sidewalls (28) of the fuse elements (27) of about 0.36 to 0.58, preferably about 0.47 equivalent.

The radially inner, circumferentially extending edges of the securing elements (27) are provided with sawtooth-shaped claws (29) for the radial engagement in the tube material. Then, the securing elements (27) are integrally connected to each other in the circumferential direction, so that there is a locking ring having a separating gap or at most two 180 ° apart separating column, so that the diameter of the securing ring during clamping of the clamp (3) can change.

To produce the securing device (5) or (6), a flat spring steel sheet metal strip is punched into a mold, as shown in FIG. 3 is shown. This sheet metal strip has sawtooth-shaped claws (29) and preferably the side walls (28) of the securing elements (27) delimiting, approximately V- or U-shaped, diverging cuts (30) on circular arcs with a curvature radius corresponding to the outer radius of the radius (R). in its longitudinal edges. The in the shape of FIG. 3 stamped sheet metal strip is then, bending the side walls (28) along the straight lines shown in dashed lines, formed into a circular arc, as shown in FIG. 2 is shown in sections. The angling of the side walls (28) can be done by means of profile rollers, which is followed by a bending tool that bends the angled sheet metal strip in the circular shape

When punching the metal strips arise at the one cutting edge of the cut surfaces burrs (31), see. in particular Fig. 4, while the burrs (31) opposite cut edges (32) when punching by the oblique edge of the punching whisker inevitably slightly rounded. The side walls (28) are therefore angled so that the ridges (31) on the radially inner side of the finished bent securing elements (5) and (6) come to rest.

However, the sheet metal strip can also be pre-rounded before punching at its later radially outer longitudinal edge, in order to achieve an even more effective rounding of the cut edges (32), so that the cut edges (32) slide with high security on the inner surfaces (25).

The safety devices (5) and (6) are dimensioned so that after being inserted into the annular spaces (17) and (19) with the rounded edges (32) of their side walls (28) to which the Ringkammem (17) and (19 ) bounding inner surfaces (25) of the annular chamber walls (20) to (23) and with their transverse walls (33)

-4AT394 896 B (Fig. 4) abut the bottom of the ring chambers (17) and (19). The securing devices (5) and (6) are therefore centered, in particular because of their trapezoidal shape, in the annular chambers (17) and (19) during insertion. Furthermore, the inner radius of the securing devices (5) and (6) is smaller than the inner radius (FIG. Rj) of the clamp halves (13) and (14) so ​​that the teeth (29) project radially inwardly beyond the sidewalls (20) to (23).

The screws (15) and (16) may be omitted but, if provided, increase the locking effect of the securing devices (5) and (6).

First, consider the case that the screws (15) and (16) are not present, as shown in Fig. 4.

When tensioning the clamp (3), the clamping force (F) is then transmitted via the transverse wall (33) of each securing element (27) in its side walls (28). From there, the flow of force due to the support of the side walls (28) on the inner surfaces (25) is deflected radially and transmitted via the claws (29) radially into the pipe material, wherein the teeth (29) engage in the pipe material. A portion of the clamping force of the clamp (3) is also on the inclined inner surfaces (25) on the side walls (28) transmitted radially, so that the side walls (28) in addition by the annular chamber walls (20) to (23) radially to the peripheral surfaces of Pipes (1) and (2) are pressed. In this way, an axial slipping of the claws (29) from the outside of the tubes during tensioning of the clamp (3) by the abutment of the side walls (28) on the inner surfaces (25) is prevented, although the inclination angle (ß₂) is relatively small. The small angle of inclination (ß₂), however, allows the side walls (28) to act practically like thrust plates capable of absorbing high axial forces, whether tensile or compressive, exerted on the tubes (1) and (2). Should the inclination angle (ß₂) increase the erection of the side walls (28), thereby the radial pressure force of the claws (29) is increased to the tube material and thus ensures a more solid grip of the claws (29) in the tube material. The coupling therefore provides a secure connection of the two tubes (1) and (2), which withstands not only high tensile forces, but also high compressive forces that would lead to a crushing of the sealing rib (26).

With the screws (15) and (16), the Verkrallungseffekt the safety devices (5) and (6) can be significantly strengthened.

In all cases, the ridges (31) facilitate penetration of the claws (29) into the tubing while the rounding of the edge (32) engages the sidewalls (28) of the locking elements (25) with the annular chamber walls (20) through (23). prevented.

By the distance between the radially inner surface of the annular chamber walls (20) to (23) from the outside of the tubes (1) and (2) due to the different radii (Rj) and (R) (see Fig. 4) it is ensured that the clamping force (F) is not transmitted directly to the pipes (1) and (2) via the clamp (3) or the annular chamber walls (20) to (23).

Instead of the in Fig. 1 dashed lines shown second flanges (11) and (12) with corresponding clamping screws can also be a the two clamp halves (13) and (14) connecting joint be provided, either with a hinge pin or with a hinge. In any case, the insertion of the securing elements (27) due to their mutual connection is relatively easy, since several or all fuse elements (27) of each securing device (5) and (6) suddenly in the associated annular chamber (27) or (19) can be inserted. The one-piece connection of the securing elements (27) allows easy production from a single sheet metal strip,

The clamp (3) can also be used without the sealing sleeve (4) only for axial securing one of the two through the clamp (3) passed through tubes (1) or (2), wherein the clamp (3) the pipe in question with a stationary object , z. B. a building wall, connects via an unillustrated connection device. Hiebei acts the clamp (3) as a stationary pipe holder and fixed point within a series of interconnected pipes, which are mounted axially displaceable within a stationary holder for thermal expansion compensation.

The clamp (3) of FIG. 5 differs from that of FIGS. 1 to 4 essentially only in that it has on its inner side only a circumferential annular chamber (17 '), which only in the area between the flanges (11 ) and (12) of the clamp halves (13) and (14) is interrupted. The annular chamber (17 *) contains both securing means (5,6) and is bounded by axially outer side walls (20) and (23) in the form of radially inwardly projecting flanges.

The axial cross section of the annular space of the annular chamber (17 ') is approximately trapezoidal, wherein the annular space bounding inner surfaces (25) of the side walls (20) and (23) have a relative to the tube longitudinal direction relatively large inclination angle (ßj).

Instead of the clamping screws (15,16) of FIG. 1 are shown schematically as dotted lines means (15 ') and (16 *) for securing the securing means (5) and (6) on the clamp shell, z. As screws, rivets or spot welds provided.

The fastening means (15 ') are associated with the securing device (5) and the fastening means (16 *) of the safety device (6) and distributed in each case over the circumference of the clamp (3).

-5AT394 896B

The securing devices (5) and (6) are inserted into the annular chamber (17 ') in such a way that they engage with the rounded edges (32) of their axially outer side walls (28) on one of the inner surfaces defining the annular chamber (17') ( 25) of the annular chamber walls (20) and (23) and abut with their transverse walls (33) at the bottom of the annular chamber (17 *).

When clamping the clamp (3), the radially acting clamping force (F) via the transverse wall (33) of each securing element (27) in the side walls (28) is transmitted. From there, the power flow is transmitted via the claws (29) radially into the tube material, wherein the claws (29) engage in the tube material. A portion of the clamping force of the clamp (3) is also radially transmitted via the inclined inner surfaces (25) on the axially outer side walls (28), so that the axially outer side walls (28) through the annular chamber walls (20) and (23) radially pressed against the peripheral surfaces of the tubes (1) and (2). In this way, and by the abutment of the axially outer side walls (28) on the inner surfaces (25), an axial slipping of the claws (29) from the outside of the tubes during tensioning of the clamp (3) is prevented, although the inclination angle (ß₂) is relatively small. The small angle of inclination (ß₂), however, allows the side walls (28) to act practically like thrust plates capable of absorbing high axial forces, whether tensile or compressive forces exerted on the tubes (1) and (2). Should the inclination angle (ß₂) increase the erection of the side walls (28), thereby the radial pressure force of the claws (29) is increased to the pipe material and thus ensures a more solid hold of the claws (29) in the pipe material. Therefore, the coupling also causes a secure connection of the two tubes (1) and (2), which withstand not only high tensile forces, but also high compressive forces, which would lead to a crushing of the sealing rib (26)

The modification of Fig. 6 differs from that of FIG. 5 only in that the axially inner side walls (28 *) of both securing devices (5) and (6) has a larger inclination angle (ß₃) of about 60 ° with respect to the axial direction than the axially outer side walls (28), d. H. have a greater slope relative to the axial direction. This not only contributes to a reduction in the cost of materials for the securing devices, because the side walls (28 ') are radially shorter than the side walls (28), but also increases the tendency of the side walls (28'), upon exercise of an axial tensile force To raise the tubes (1) and (2) radially and to provide for an even firmer jamming of the clamp (3) on the tubes.

The fastening means (15 ') and (16') may be omitted if no excessive axial compressive forces exerted on the tubes (1) and (2) are to be expected or if the sealing sleeve (4) is inside the annular chamber (17 '. ) is surrounded by a tensionable clamp with radially inwardly projecting end flanges, against which the axially inner, mutually facing side walls (28) (according to FIG. 5) or (28 ') (according to FIG. 6) axially support. The end flanges of such an additional inner clamp together with the side walls (20) and (23) each have their own annular chamber, as in the case of FIG. 1, limit.

Compared to the pipe coupling of FIG. 1, there provided, formed on the inside of the clamp body ribs as chamber walls (21) and (22), so that the clamp body can be bent in a simple manner from sheet metal.