HOLDING RING FOR CREATING A TENSION-RESISTANT PIPE CONNECTION AND PIPE ARRANGEMENT PRODUCED THEREBY

Description

[0001] The invention relates to a retaining ring for creating a tensile-resistant pipe connection according to the preamble of claim 1, and a pipe arrangement using two such retaining rings.

[0002] From EP 0 175 169 A1 a pipe connection is known in which two axially arranged ring-shaped elements together form a retaining ring and have complementary inclined surfaces, so that they can generate clamping forces in the axial direction by a rotary movement, either in the manner of a bayonet fitting or in the manner of a screw thread, in order to hold two nested pipes together and connect them in a tensile-resistant manner.

[0003] EP 2 218 956 A2 discloses a pipe joining device for connecting two pipes by clamping the two pipes using shell-like retaining elements. A positive-locking connection is proposed, whereby the retaining elements each have a base wall section with radially inwardly projecting legs that extend inwards at essentially right angles and engage behind a circumferential bead of a pipe. A further leg section forms a slip-resistant contact section from which a convexly shaped indentation section projects radially inwards, whereby no wedge or notch effect is exerted during indentation and thus the pipe surface is not damaged.

[0004] WO 2012 / 149010 A2 describes a pipe connection using a retaining ring with inner and outer retaining elements. An outer retaining element has a radially inwardly directed retaining rib that engages behind a bead of a first pipe. Inner retaining elements are provided with engagement projections that engage the surface of a second pipe when the outer retaining elements are screwed together.

[0005] US 4,609,210 A further teaches a pipe connection using two half-rings, wherein the half-rings have an inner contour that accommodates a bead of a first pipe, and wherein the half-rings have a retaining section with a retaining profile that rests against a second pipe. Screws connect the half-rings to form a retaining ring.

[0006] From US patent 2018 / 0 216 772 A1, which represents the closest prior art, a closed retaining ring is known that, on the one hand, has several retaining claws that grip the wall of a first pipe, and on the other hand, engages from the outside with several elastically expandable retaining fingers in a groove of a pipe socket of a second pipe body to hold the two nested pipes together and connect them in a tensile-resistant manner. The retaining fingers are spaced apart from each other along the circumference of the retaining ring, so that the outer surface of the retaining ring has a radial interruption along its circumference – namely between the retaining fingers.

[0007] The invention is based on the objective of improving a generic retaining ring in such a way that it enables a particularly reliable tensile strength of a pipe connection even in confined assembly situations, and of specifying a corresponding pipe arrangement.

[0008] This problem is solved by a retaining ring according to claim 1 and by a pipe arrangement according to claim 12. Advantageous embodiments are described in the dependent claims.

[0009] Features of the invention are described below.

[0010] The invention proposes that the retaining ring has a break around its circumference, so that in the area of ​​this break the retaining ring does not extend radially outwards as far as in its remaining, uninterrupted circumferential region. For example, the retaining ring can extend to varying degrees in the axial direction, so that it has a break at one axial end, which can also be described as a notch, recess, or constriction, and which at this axial end ensures that the radial extension of the retaining ring is reduced compared to the adjacent circumferential regions at the same axial end of the retaining ring.

[0011] According to the invention, the retaining ring is formed from at least two partial rings, each extending over a partial circumference of the retaining ring. Two adjacent partial rings are connected to each other by clamping means, so that their distance from each other is variable.

[0012] The proposed retaining ring can be used to create a straight connection between two pipes, thus making it suitable as a standard component for pipe joints. The break in the design proves particularly advantageous when the retaining ring is used for mounting on branch connections.

[0013] In the area of ​​branch connections, where pipelines meet in an approximately Y-shaped configuration, one pipeline typically runs straight through, and a second pipeline connects to it at a specific angle. This creates a gusset between the two pipelines, which, depending on the angle of the second pipeline's connection, offers very limited installation space for mounting retaining rings. A proposed retaining ring can be mounted with its angle of rotation such that the break points towards the other pipeline. In the area of ​​the break, the retaining ring occupies less space radially than in its surrounding area, thus providing more installation space for the second retaining ring within the aforementioned gusset.The second retaining ring can therefore be mounted in such a way that it penetrates the first retaining ring, designed as proposed, in the area of ​​its interruption. In this context, penetration means that, if the contour were imaginarily continued over the entire circumference of the retaining ring, the interruption would represent a defect within this contour, and that the second retaining ring penetrates into the imaginary, continued circumferential contour of the first retaining ring in the area of ​​this defect.

[0014] It may be that not only a single retaining ring mounted in a branch has a break, but both retaining rings installed on either side of the gusset may each have a break. This allows both retaining rings to interpenetrate at their respective breaks, enabling easy installation even in particularly confined spaces.

[0015] The clamping elements of the retaining ring can be designed as screws, allowing for easy handling on the construction site. The length, and thus the adjustment range, of the screws allows for simple determination of the maximum diameter change of the retaining ring that is possible without completely loosening the screws from their respective nuts. Not having to completely loosen the screws is advantageous because it eliminates the need to handle loose parts during installation that could be lost and difficult or impossible to locate in a trench, shaft, or similar location, potentially causing significant delays. Using a closed retaining ring with a relatively large initial gap between its segments further simplifies installation, as it eliminates the need to join two segments at a junction, for example.Screws must be inserted into the corresponding nuts. The use of a closed retaining ring is always possible if the pipe connection is accessible in the axial direction and a retaining ring can be slid on axially and moved to the desired mounting position.

[0016] In one embodiment, the retaining ring has not just a single interruption along its circumference, but rather two interruptions in the retaining rib and the outer surface, with the two interruptions spaced apart along its circumference. In the described arrangement of the retaining ring in the bend of a pipe branch, only a single interruption is required, namely only in the circumferential area of ​​the retaining ring facing the second pipe. However, providing two interruptions in the retaining ring allows it to be aligned in two different rotational positions during installation. This ensures good accessibility to the clamping elements even in a wide variety of installation situations.

[0017] The effectiveness of the holding claw can be improved by applying pressure to a specific point on the holding claw.

[0018] In one embodiment, a clamping ring is provided as a clamping device. This ring runs around the outside of the claw section of the retaining ring and exerts a radially inward-directed pressure effect as its circumference decreases. Because this pressure effect is concentrated at the point where the retaining claw is located, the effectiveness of the retaining claw is improved. It is economically advantageous to use elements as retaining claws that are not specifically designed and manufactured as such, but are, for example, commercially available as semi-finished products and therefore cost-effective.

[0019] Accordingly, the retaining claw can be designed so that it does not extend over a large part or even practically the entire circumference of the claw section, but rather only over a small portion. This not only facilitates cost-effective manufacturing of the pipe connection through the use of the aforementioned semi-finished products, but also, because the retaining claw only extends over a small portion of the claw section, increases the desired localized pressure effect, thus ensuring a particularly reliable positive engagement of the retaining claw with the surface of the first pipe.

[0020] It can be advantageous to use not just a single retaining claw, but at least two, and especially several, retaining claws distributed around the circumference of the claw section. In this way, the most uniform possible retaining forces are achieved circumferentially, securing the first pipe in the socket of the second pipe against pulling forces. For this reason, the arrangement of the two or more retaining claws can be advantageously provided in such a way that the retaining claws are distributed around the circumference of the claw section in a uniform pattern, e.g., by having equal distances from each other, being arranged symmetrically or in pairs, or the like.

[0021] In a first basic embodiment, the retaining claw is designed to project radially outwards beyond the claw section, so that the clamping ring rests directly against the retaining claw and exerts a direct, localized pressure on the retaining claw that is greater than at the two points located on either side of the retaining claw around the circumference of the clamping ring. It is advantageous that, due to the direct contact of the clamping ring with the retaining claw, the full inward-acting compressive force exerted by the clamping ring is transmitted undiminished to the retaining claw.

[0022] In a second fundamental embodiment, the point pressure acting on the retaining claw is not achieved directly, but rather by means of a pressure piece arranged between the clamping ring and the retaining claw, so that the clamping ring acts indirectly on the retaining claw. In this second embodiment, it is not necessary for the retaining claw to project outwards beyond the circumference of the claw section. Instead, the claw section can be closed on its outer circumference and have a recess on its inner circumferential surface that is radially open inwards, into which a retaining claw can be inserted that projects radially inwards beyond the inner circumferential surface of the claw section. This simplifies the manufacture of the retaining ring, as no windows are required in the claw section through which the retaining claw projects radially both inwards and outwards.The design of the retaining claw in the claw section can be simplified as a result, and in particular there is no risk that an accidental external pressure on the retaining claw before the mounting of the retaining ring could cause the retaining claw to be pushed out of the aforementioned window of the claw section and be lost.

[0023] In one variant of this second basic design, the pressure piece can, for example, be configured as a radially inwardly projecting projection in the clamping ring. Even if the claw section of the retaining ring is closed on the outside, the pressure piece can exert pressure on the claw section at the point where the retaining claw is located within the claw section.

[0024] In a second variant, the pressure piece can be designed as an outwardly projecting extension of the claw section. This second variant has the advantage that the alignment of the clamping ring is simplified when positioned on the claw section, since it is not necessary to ensure that a pressure piece arranged on the clamping ring is precisely aligned with the holding claw. Rather, in this second variant, the clamping ring automatically rests against the radially outwardly projecting pressure piece.

[0025] The retaining claw can, in one embodiment, have a thread. Accordingly, screws, appropriately cut lengths of threaded rods, or the like can be used. The threaded retaining claw extends axially along the first tube, so that the individual threads form claws that run transversely to the tube's longitudinal direction and thus provide a barrier against pulling forces, i.e., against movement of the tube in its longitudinal direction that would attempt to pull the first tube away from the second tube. If screws are used as retaining claws, they can, for example, be inserted obliquely into the claw section so that not the screw head, but rather the thread, protrudes radially inwards and can interact with the first tube.However, if the screw head also forms a narrow edge, as is the case with countersunk screws, the angle of the screw can be chosen so that both the circumferential outer edge of the screw head and a section of the thread project radially inwards over the inner surface of the claw section.

[0026] For example, the retaining claw can be designed as a setscrew, so that the claw section does not need to be adapted to accommodate a screw head and can therefore be manufactured in a simpler and more cost-effective manner. Setscrews have a drive point at one end, for example in the form of a slot, a Phillips head, a hex socket, or the like, and typically a point at the opposite end. By appropriately dimensioning a recess, arranged in the form of a window or a recess in the claw section of the retaining ring, which serves to receive the retaining claw, the setscrew can be easily fastened in the retaining ring. The recess can be dimensioned so that the point of the setscrew is pressed into the material of the claw section before its opposite end can be fully inserted into the recess.This allows the grub screw to be held in the recess without the use of additional means, such as adhesive, a retaining clip or the like, so that it remains in its intended position until the retaining ring is fitted.

[0027] The tensile-resistant pipe connection can be used to join two identical pipes, each having a spigot end on one side and a socket end on the other. However, one embodiment allows for the connection of pipes that are particularly easy and inexpensive to manufacture, as they do not require a socket end during production and therefore have a spigot end at both ends. The connection of two such pipes is achieved using a connecting component designed as a double socket, i.e., a second pipe with a socket at both ends. This double socket is typically not as long as either of the two original pipes.While the first pipes can be manufactured using extrusion, the double socket can be produced as an injection-molded part. To minimize mold costs, the double socket can be only one decimeter or less in length. The injection-molded design allows for precise shaping of the circumferential bead with small transition radii, resulting in a bead with a nearly angular cross-section. This ensures a particularly reliable, positive-locking connection of the retaining ring to the second pipe. Because of this precise and nearly angular bead design, high retention forces are achieved, and even when high pulling forces are applied, the retaining ring cannot be pulled over the bead, which would otherwise be possible with a bead with a highly rounded cross-sectional contour.

[0028] The retaining ring engages the bead of the second tube in such a way that it is secured against pulling forces, i.e., forces that would pull the retaining ring away from the second tube. Viewed from the end of the second tube from which the first tube protrudes, the retaining ring thus engages behind the bead of the second tube. In one embodiment, the retaining ring can be secured not only against pulling forces but also against pushing forces, and accordingly, it is positively locked to the second tube in both axial directions by means of the bead, preventing displacement. This ensures that movements which could loosen the retaining ring are prevented, thus guaranteeing the most stable possible cohesion of all components of the tube connection.

[0029] In one embodiment, the retaining ring is divided along its circumference into segments, referred to as sub-rings, each extending around a circumferential section of the first and second tubes. The retaining ring is composed of sub-rings, each describing an arc as a circular segment, with the sub-rings together forming the complete retaining ring. In one embodiment, the sub-rings can together describe a circular arc of less than 360°, so that in a retaining ring consisting of two sub-rings, each sub-ring describes an arc of slightly less than 180°. This allows the sub-rings to achieve maximum effective tension with which they can be fixed to the first and second tubes, without the build-up of such tension being prevented by the sub-rings abutting each other.

[0030] Because the retaining ring is divided into sub-rings, the retaining rib is also divided into several inwardly projecting retaining rib sections, since each sub-ring has at least one of its own retaining rib sections, so that the sub-rings of the retaining ring have essentially no functional differences compared to the previously known retaining ring, which simplifies handling and reduces susceptibility to errors.

[0031] In one embodiment, not every section has a retaining rib, so that sections without a retaining rib can be inserted between sections that each have a retaining rib, thus limiting the effect of the retaining rib to circumferential sections of the retaining ring where it is particularly necessary, while in one or more other circumferential sections a design of the retaining ring that is as flat as possible in the radial direction can be achieved, for example to facilitate its installation in a branch or to enable it in particularly narrow bends of pipe branches.

[0032] The partial rings are initially supplied in a pre-assembled arrangement. In one embodiment of the pre-assembled arrangement, all partial rings can be completely separate and simply fitted with clamping devices, e.g., eccentric clamping devices or screws on one side and nuts on the other, so that the clamping devices do not need to be handled as individual parts. The separate partial rings make it possible to position the retaining ring around an existing pipe connection of an already installed pipeline and then connect them together, e.g., with screws, to create a closed retaining ring.

[0033] In another embodiment of the pre-assembled arrangement, the partial rings can be connected to each other by clamping devices at only one separation point, while at one or more other separation points they maintain a fixed distance from each other and can, for example, be connected by hinges. To distribute the pressure exerted by the retaining ring on the pipe as evenly as possible around the circumference, in another embodiment the adjacent partial rings at all separation points can be connected to each other by clamping devices, so that the distance between the partial rings can be changed at each separation point.

[0034] In one embodiment of the pre-assembled arrangement, all the partial rings can already be connected and have an initial gap between them, so that the partial rings form a closed ring. The gaps between the partial rings, known as this initial gap, are comparatively large. Because the partial rings are already connected in their pre-assembled configuration, handling is simplified. In particular, on-site work is accelerated compared to having to handle the partial rings separately and then assemble them into the retaining ring after placing them on a pipe. The so-called initial gap between the pre-assembled partial rings is large enough to allow them to be guided over the bead of the second pipe in the pre-assembled configuration. The inwardly projecting retaining rib sections are correspondingly spaced far apart.By dividing the retaining ring into segments or partial rings along its circumference, installation of the retaining ring is still possible even when the pipe connection makes sliding the retaining ring on axially difficult or impossible, for example, after the spigot end of the first pipe has already been inserted into the socket end of the second pipe, as is the case with already installed pipelines. Consequently, the multi-part retaining ring allows existing pipe connections to be retrofitted against pulling forces in an economically advantageous manner, if necessary.

[0035] In one embodiment, the partial rings are connected to each other at only a single separation point by clamping means, while at one or more other separation points they have a fixed distance from each other and can, for example, be connected to each other by hinges. In order to distribute the pressure exerted by the retaining ring on the tube as evenly as possible around the circumference, in another embodiment the partial rings adjacent to each separation point can be connected to each other by clamping means, so that the distance between the partial rings can be changed at each separation point.

[0036] Regardless of whether the partial rings are separated or already connected in their pre-assembled arrangement, they can be moved from the pre-assembled arrangement, referred to as the first arrangement of the partial rings, to a second arrangement, referred to as the assembled arrangement, in which they have a second distance from each other that is smaller than the first distance. The retaining ring then has a circumference that is smaller than the circumference in the first, pre-assembled arrangement and is adapted so that, in the assembled, second arrangement, a retaining rib, which engages behind the bead of the second tube, provides a positive-locking hold of the retaining ring on the second tube, securing the retaining ring against pulling forces on the second tube.The inwardly projecting retaining rib sections are accordingly spaced closer together than in the first arrangement of the retaining ring, so that they engage behind the bead of the second tube. In the second arrangement, the partial rings are held together by clamping devices, for example by screwing the partial rings together, so that the diameter of the mounted retaining ring and retaining rib cannot be undesirably enlarged.

[0037] When the partial rings are in their assembled configuration and either nearly or actually abut each other, the retaining rib does not have a circular inner contour. Rather, the retaining rib sections extend radially inwards to varying degrees, creating a common inner contour that deviates from a perfect circle. At the respective ends of the retaining rib sections, where one partial ring is adjacent to another, the retaining ring has a larger inner diameter than at the circumferential distance from this end.

[0038] This non-circular inner contour of the retaining rib allows the retaining ring to be pulled off the second tube axially, or slid onto the second tube and over its circumferential bead, even with a relatively small increase in the distance between the partial rings. The clamping devices that hold the partial rings together can therefore accommodate movement between their pre-assembled and assembled positions with a comparatively small adjustment range. This relatively small required adjustment range of the partial rings allows for greater design freedom in the retaining ring, particularly regarding the design of the clamping devices. For example, eccentric clamping devices can be used, which have a comparatively small adjustment range compared to other clamping devices.However, if screws are used as clamping devices to connect the partial rings to each other, similar to the elements of a pipe clamp, the operation of the screw can effect the movement of the partial rings between their pre-assembled and their mounted arrangement with comparatively few turns, thus making it easier for the user to handle the pipe connection and enabling the pipe connection, including the mounted retaining ring, to be made in a shorter time.

[0039] In one embodiment, the retaining ring can consist of only two sub-rings. This simplifies handling the retaining ring in the pre-assembled arrangement, because either the individual sub-rings must be handled separately, which is easier with a smaller number than with a larger number, or the sub-rings are already connected to each other in the pre-assembled arrangement, relatively loosely and therefore movable, so that in this case too, a smaller number of sub-rings facilitates their correct alignment on the second tube before the clamping devices can be tightened.

[0040] In one embodiment, the clamping devices are designed as screw connections. This allows for the use of very inexpensive components, and the appropriate tool for operating the screw connection is readily available on virtually every construction site, ensuring trouble-free operation of the clamping devices. This is often made particularly easy for the user with motorized tools such as a cordless screwdriver. If, as is frequently the case in practice, a specific tightening torque can be set on the aforementioned cordless screwdriver, it can be ensured very easily that the clamping devices act with the intended clamping force, thus guaranteeing the correct installation of the retaining ring with exceptional ease.

[0041] The retaining ring extends over a specific axial length. The retaining claw is positioned at a specific point along this axial length on the circumference of the retaining ring. Clamping devices can be arranged at the location of the retaining claw on the circumference of the retaining ring. This ensures that the retaining claw is pressed against the first tube and can penetrate its surface to provide the desired locking action against longitudinal movement of the first tube relative to the retaining ring.

[0042] Based on a similar consideration, clamping elements may be arranged axially on the retaining ring in the area where the retaining rib runs along the circumference of the retaining ring. For example, if a stiffening rib also projects outwards on the outside of the retaining ring where the retaining rib projects inwards, the clamping elements may be slightly offset axially to avoid interrupting the outer stiffening rib. Despite this slight axial offset, they remain in the area where the clamping force acts on the retaining rib in such a way as to counteract any undesirable widening of the rib.

[0043] It may therefore be advantageous to arrange two or more clamping devices one behind the other in the axial direction, so that the two aforementioned effects on the holding claw and on the holding rib can be achieved.

[0044] When creating a pipe branch, a fitting can be used, which is essentially Y-shaped and, according to a common and widely used design, has a first, straight, continuous pipe section and a second pipe section that joins the first pipe section at a specific angle. One end of the first, continuous pipe section can be a spigot end, and the opposite end a socket end with a circumferential bead. The second, branching pipe section also has a socket end with a circumferential bead.

[0045] The sealing ring mentioned so far, which extends over both pipes of the pipe connection, serves to seal the two pipes against each other. An additional seal can be provided between the retaining ring and an outer surface of the first and / or the second pipe, for example, to prevent roots from penetrating between the retaining ring and the pipes. This additional seal can be designed as an O-ring or as a profiled sealing ring with a specific cross-sectional geometry, or it can be created by a sealant that is poured into a gap or cavity between the retaining ring and the pipes.

[0046] If the retaining ring is circumferentially divided into two or more partial rings and the use of a closed retaining ring is not possible because the pipe connection is not accessible in the axial direction and the retaining ring therefore cannot be slid on axially, the retaining ring must be open between two partial rings. If the two partial rings are connected by clamping devices and these are designed as screw connections, even with this open design of the pre-assembled retaining ring, the clamping devices can be securely held to the respective partial rings. This prevents small parts from being lost, just as with a closed pre-assembled retaining ring. These small parts would be difficult or impossible to find on the construction site and could undesirably delay the work involved in making the pipe connection.

[0047] To ensure the clamping devices are securely attached to the respective sub-rings, the sub-rings can have bendable tabs. These tabs allow the clamping devices to be initially mounted on the sub-rings and then bent over to secure them. For example, the tabs can extend axially parallel to a screw and nut, allowing the screw or nut to be positioned in the desired position on the retaining ring. The screw can then be temporarily fixed in its desired position by extending its shank through a corresponding hole. Finally, bending the tab over the screw head secures the screw in this position.

[0048] If the tab extends only over the edge of the screw head, or if the tab has an opening, the force application of the screw head remains accessible, allowing the screw held by the tab to be driven with a suitable tool. Therefore, it can be particularly advantageous for the screw head to have a central force application, such as a Phillips, Allen, or Torx drive, rather than a circumferential force application, as is the case with an external hexagon.

[0049] For the corresponding nut, the position fixation provided by a bent tab not only ensures that the nut is securely held on the retaining ring, but also prevents it from shifting axially during tightening. In particular, the tab can also prevent the nut from rotating. This simplifies the installation of the retaining ring, as only the screw head needs to be accessible for tightening, and the nut does not need to be held in place. For example, a recess with a hexagonal inner contour can be provided to accommodate the nut, ensuring that it is reliably secured against unwanted rotation even when high tightening torques are applied.

[0050] The tabs can be made of different materials. Metallic tabs can be mechanically bent, for example using a screwdriver, and plastic tabs can be thermally bent using a heated tool such as a soldering iron, or they can be crimped, i.e., compressed using a heated tool so that their cross-section deforms into an approximate mushroom shape.

[0051] The individual rings of the retaining ring can be designed identically for economic reasons. If clamping elements designed as screws are provided, each individual ring can have different designs at its two opposite ends, to which another individual ring connects, as will be explained in more detail below. Adjacent individual rings abut each other at their different ends. In this design of a multi-part retaining ring, the ring advantageously has an even number of individual rings, so that, without requiring a special intermediate element, all individual rings can always connect at their two different ends to a complementary end of the respective adjacent individual ring.

[0052] For example, one of the two different ends of the partial ring can, in one embodiment, serve to form a chamber, namely by having a collar which, together with the pipe surface and the adjacent partial ring, creates a receiving space through which the clamping element extends to the aforementioned adjacent partial ring. This chamber protects the clamping element, for example, from escaping sealant when the sealing ring of the pipe connection is created by a potting compound injected into the cavity between the retaining ring and the pipe surface.

[0053] For example, the two different ends of the partial ring can be adapted in one embodiment to the clamping devices used, for example to either accommodate a screw rotatably or a nut in a rotationally secured manner and, if necessary, to have the aforementioned tabs for securing clamping devices.

[0054] However, it can be advantageous, particularly when unobstructed access to a retaining ring is only possible from one side, to allow the optional attachment of a screw or nut at both ends of the partial ring. In the case of a retaining ring consisting of only two partial rings, this allows the screws to be inserted from the same side at both separation points, ensuring easy access for tightening the retaining ring and moving it from its first configuration to the second configuration with a reduced diameter. For example, a partial ring can have a recess with a hexagonal inner contour at each of its two ends, allowing either a nut to be securely held or a screw head with a circular circumference to be rotatably accommodated.

[0055] To prevent unwanted subsequent manipulation of the retaining ring, clamping devices designed as screws can be made permanently fixed. This can be achieved, for example, by using so-called shear bolts, where the bolt head shears off the bolt shaft when a predetermined tightening torque is reached, or by an asymmetrical force application of the bolt, so that the bolt can only be tightened, but not loosened.

[0056] The invention is explained in more detail below with reference to the purely schematic representations. These show Fig. 1 a longitudinal section through a tensile-resistant pipe joint, including an enlarged detail, Fig. 2 a side view from the outside of the pipe joint of Fig. 1 , Fig. 3 a section along line III - III in Fig. 2 , including an enlarged section, Fig. 4 a longitudinal section through another tensile-resistant pipe connection, including an enlarged section, Fig. 5 a perspective view of a retaining ring that is not part of the invention, Fig. 6 a longitudinal section through a pipe connection, including an enlarged section, Fig. 7 a side view from the outside of a pipe connection including a retaining ring according to the invention, Fig. 8 a side view from the inside of a partial ring of the retaining ring of Fig. 7 , Fig. 9 an axial view of the arrangement of Fig. 7 , Figs. 10 and 11 perspective views from two directions of the retaining ring of Fig. 7 , and Figs. 12 to 14 show views from different directions of a pipe branch with two pipe connections and the respective retaining rings.

[0057] In Fig. 1 Figure 1 shows a tensile-resistant pipe connection 1, wherein a first pipe 2 has a spigot end with which it engages a socket end of a second pipe 3. The second pipe 3 has an outwardly projecting, circumferential bead 4. A sealing ring can be inserted into the bead 4, which forms a radially inwardly open groove, as is known from pipe connections in general. To avoid damaging such a sealing ring when joining the pipes 2 and 3, the spigot end is typically chamfered. In the illustrated embodiment, particularly cost-effective manufacturing of the first pipe 2 is facilitated by minimizing the number of machining steps required. Therefore, the spigot end of the first pipe 2 is not chamfered, and no sealing ring is provided in the bead 4.

[0058] Rather, a sealing ring 5 is arranged inside a retaining ring 6, so that this sealing ring 5, together with the retaining ring 6, is mounted on the first tube 2. The retaining ring 6 consists of several segments, in the illustrated embodiment of two segments, so that the retaining ring 6 can be opened by increasing the distance between the two segments and, in this open state, can be easily guided over the first tube 2. The two segments are then brought together so that the retaining ring 6 now, firstly, positively engages the bead 4 of the second tube 3 and is secured to the second tube 3 in both axial directions, preventing displacement. Secondly, the retaining ring 6 now rests against the first tube 2 with a claw section 7. The two tubes 2 and 3, as well as the retaining ring 6, define a cavity 31 in which the sealing ring 5 is received.

[0059] Several retaining claws 8 are arranged along the circumference of the retaining ring 6 within the claw section 7. Each retaining claw 8 is designed as a set screw and is axially oriented. They are each received in a recess 9 of the claw section 7, the recess 9 being dimensioned such that the retaining claws 8 project radially inwards beyond the inner surface of the claw section 7 and thus engage positively with the first tube 2. A clamping ring 10, the diameter of which is variable, runs around the outside of the claw section 7 and serves to exert pressure on the retaining claws 8, so that they are held in place as described in the diagram. Fig. 1 depicted penetrating the surface of the first tube 2.

[0060] In contrast to an adhesive or welded joint, a retaining claw 8 counteracts a pull-out movement of the first pipe 2 even after an overload of the pipe connection, after the two pipes have moved relative to each other, since the deformability of the retaining claws is advantageously lower than that of the first pipe 2. The retaining claws counteract the pull-out of the first pipe 2 over the entire path, so that the pull-out movement would otherwise lead to the formation of grooves in the outer surface of the first pipe 2.

[0061] Fig. 2 shows a side view of pipe connection 1 of Fig. 1 .

[0062] Fig. 3 shows a cross-section through pipe connection 1 of Fig. 2 along the line III - III of Fig. 2 A total of four retaining claws 8 are arranged symmetrically around the circumference of the claw section 7. The retaining ring 6 consists of two partial rings 15, the two ends of which run obliquely and not coaxially to the central axis of the pipe connection 1, so that the dividing lines between the two partial rings 15 are radially inside and radially outside the clamping ring 10. Fig. 3 The tension ring 10 is designed as a tension clamp, in which a tension screw 11 makes it possible to change the circumference of a steel band. In particular, it is made of Fig. 3 And here, particularly evident from the magnifying detail view, it is clear that the claw section 7 of the retaining ring 6 forms radially outwardly projecting protrusions where the recesses 9 and the retaining claws 8 arranged therein are located. These protrusions form pressure pieces 12 against which the clamping ring 10 rests. Therefore, when the diameter of the clamping ring 10 is reduced, a locally confined, almost point-like pressure is exerted on the pressure pieces 12, which is greater than the pressure acting on the claw section 7 on both sides adjacent to the pressure pieces 12. In this way, a particularly intense pressure transmission from the clamping ring 10 to the retaining claws 8 occurs.

[0063] Fig. 4 Figure 1 shows a further embodiment in which the retaining claw 8 is designed such that it also projects outwards in a radial direction beyond the claw section 7, so that the clamping ring 10 rests directly against the retaining claw 8 and exerts a direct, localized, inward-acting compressive force on the retaining claw 8, which is greater than the compressive force at the points where the clamping ring 10 rests against the circumference of the claw section 7 next to the retaining claw 8.

[0064] Fig. 5 shows a retaining ring 6, which, as already mentioned, consists of two segments, which are referred to as partial rings 15 and are in Fig. 5 The two partial rings 15 are shown in a so-called assembled arrangement, in which they are spaced a short distance apart. Clamping devices 16 connect the two partial rings 15 and hold them at this small distance. It can be seen that the clamping devices 16 are arranged axially on the retaining ring 6 at the points where the sealing ring 5 and the retaining claws 8 are located, and that they are situated near, i.e., in the area where a retaining rib 14 runs internally. Two stiffening ribs 17 run along the outside of the retaining ring 6, and to ensure their effectiveness and prevent any interruption, the clamping devices 16 are arranged axially between the two stiffening ribs 17. By actuating the clamping devices 16, these can be loosened, allowing the retaining ring 6 to be opened and the partial rings 15 to be brought into a pre-assembled arrangement in which the distance between the two partial rings 15 is greater than in the illustration. Fig. 5 In this pre-assembled state, the retaining ring 6 can easily be guided over the first pipe 2 and also over the second pipe 3, especially over its bead 4.

[0065] The two partial rings 15 are then brought together, for example, directly by actuating the clamping devices 16, or first manually and then by actuating the clamping devices 16. As a result, firstly, the retaining rib 14 of the retaining ring 6 engages the bead 4 of the second tube 3, so that the retaining ring 6 is secured against pulling forces on the second tube 3. Secondly, the retaining ring 6 now rests against the first tube 2 with its claw section 7, and the retaining claws 8 penetrate the material of the first tube 2, so that the first tube 2 is itself fixed to the retaining ring 6 in an axially immovable manner. Since the claw section 7 transitions into a subsequent section of the retaining ring 6 with a shoulder 18, and the bead 4 of the second tube 3 runs between the retaining rib 14 and the shoulder 18, the retaining ring 6 is positively locked to the second tube 3 in both axial directions and is thus prevented from shifting. A clamping ring 10 is in Fig. 5 not shown, so that the pressure pieces 12 are visible from the outside as boundaries of the recesses 9 in which the retaining claws 8 are arranged.

[0066] The retaining rib 14 is formed by two retaining rib sections 19, with one retaining rib section 19 being arranged in each partial ring 15. The circumferential retaining rib sections 19 are each reinforced by several support ribs 20 extending in the axial direction. The diameter of the retaining rib 14 widens towards the ends of the partial ring 15; the inner edges of the retaining rib sections 19 extend outwards in these areas and practically penetrate the circumference of the retaining ring 6.

[0067] When the clamping devices 16 are loosened, the two partial rings 15 can be moved apart into their pre-assembled arrangement, in which they are still connected by the clamping devices 16 to form a closed ring, but are spaced further apart. If each of the two partial rings 15 can be moved outwards and away from the other partial ring 15 by the radial height of the bead 4, the retaining rib sections 19 disengage from the bead 4. If the retaining rib 14 had a constant, circular inner contour, it would still engage the bead 4 positively with such an opening width of the clamping devices 16, namely with the ends of the two retaining rib sections 19 at the ends of the two partial rings 15.

[0068] The loosening of the clamping devices 16 causes an increase in the distance between the retaining rib sections 19 only in the longitudinal direction of the screws in the clamping devices 16, but not a circumferentially uniform increase in the distance between the retaining rib 14 and the bead 4. Because the inner contour of the retaining rib 14 is radially enlarged near the clamping devices 16, the retaining rib 14 also comes out of engagement with the bead 4 relatively early in these two areas, so that the pre-assembled arrangement is reached after a comparatively small adjustment travel of the clamping devices 16 and the retaining ring 6 can be moved longitudinally over the second tube 3 and its bead 4.

[0069] For the production of the pipe connection 1, this means that the retaining ring 6 can be slid onto the second pipe 3 in the pre-assembled arrangement of the partial rings 15 until the retaining rib 14 is located behind the bead 4 of the second pipe 3. The clamping devices 16 can then be tightened, whereby a comparatively short adjustment range of the clamping devices 16 is sufficient to move the partial rings 15 from the pre-assembled arrangement to the assembled arrangement.

[0070] Fig. 6 Figure 1 shows a pipe connection 1 in longitudinal section, with a seal 21 arranged in the cavity 31. In contrast to the sealing ring 5 designed as an O-ring, the Fig. 1 The seal 21 is designed as a profile seal. It rests on the first pipe 2 inside the retaining ring 6 and extends axially outwards to the bead 4 of the second pipe 3. By tightening the clamping means 16, the seal 21 is pressed onto the outer surface of the first and second pipes 2, 3. The seal 21 can thus form a liquid-tight barrier, the material of which is adapted to the media that are conveyed through the pipe connection 1, for example, oily wastewater or the like. In the illustrated embodiment, the seal 21 is designed as a sealing ring, which, for example, has an elastomer material or a polyamide. Alternatively, it can also be formed by a potting compound, e.g., a two-component resin, which is injected into the cavity 31 created between the two pipes 2 and 3 and the retaining ring 6.Furthermore, the seal 21 can fulfill a mechanical function in the form of a root barrier, which prevents the penetration of roots into the interior of the pipe connection 1, in particular into the interior of pipes 2 and 3. For this purpose, injection-molded, prefabricated elements can be provided, e.g. made of polyamide or the like, which are deformable under high tensile forces and can thus be particularly effective in preventing root intrusion.

[0071] The Fig. 7 bis 14 Figure 1 shows examples of retaining rings 6, some separately, some as part of a pipe connection, which are basically the same as the retaining rings 6 described above and differ from them in some details.

[0072] In the illustrated embodiments, the clamping devices 16 are designed as screws 22, which according to Fig. 7 with square nuts 23, which are arranged in a rotationally secure manner in the retaining ring 6. In contrast to the illustrated embodiment, hexagonal nuts can also be used, and the square or hexagonal nuts can optionally be designed to be self-locking. Fig. 7 The pipe connection 1 is visible from the outside. The four clamping devices 16 are also visible, as is a third stiffening rib 17 at the free end of the claw section 7. Where the recesses 9 are provided in the claw section 7, projections 24 are located on the outer circumference of the claw section 7. Each projection 24 is provided with its own short stiffening rib, which runs longitudinally over the respective projection 24 and ensures the desired clamping force of the retaining claws 8 on the respective pipe surface even without a clamping ring 10, which would otherwise be arranged around the outside and act on the projections 24, which act as pressure pieces. However, a clamping ring can also be arranged around the outside of the projections 24; in this case, it acts on the retaining claws 8 via the short ribs and the projections 24.

[0073] Fig. 8 shows a view of the radially inner side of a partial ring 15 of the retaining ring 6 of Fig. 7 .

[0074] The retaining ring 6 can be used to create a pipe connection 1 in a single pipeline, as shown in Fig. 7 This is evident. The retaining ring is also particularly suitable for use in very confined installation spaces, as will be explained in more detail later. For this purpose, the retaining ring 6 has interruptions 25 in its second section. In the illustrated embodiment, each of the two partial rings 15 has two interruptions 25. The interruptions 25 extend firstly into the retaining rib 14, thus creating a defect in the axial direction, and secondly in the radial direction, thus creating a defect on the outer surface 26. The outer surface 26 surrounds the retaining rib 14 radially and connects the second section of the retaining ring 6, in which the retaining rib 14 is located, with the claw section 7.

[0075] Out of Fig. 9 The two partial rings 15 are shown in their assembled arrangement, in which they are spaced a short distance apart and fit snugly against the two tubes 2 and 3. In contrast to the illustrated embodiment, the retaining ring 6 can also consist of more than two partial rings 15. Due to the narrow remaining gap between the two partial rings 15, the clamping elements 16, designed as screws 22, are visible in the gaps between the two partial rings 15.

[0076] The Fig. 10 und 11 The two partial rings 15 are shown in their assembled arrangement and from different perspective views. In Fig. 11 A filling opening 27 is shown, which can be used to fill with a sealant that complements the sealing ring 5 in terms of its sealing effect and / or can serve as a root barrier. The sealant can completely fill a cavity 31, in which the sealing ring 5 or a profiled seal 21 is also located and which is in the Fig. 12 bis 14 The cavity 31 extends in the axial direction of the pipe connection 1 over both the first pipe 2 and the second pipe 3. It is bounded radially outwards and at its two axial ends by the retaining ring 6, and radially inwards by the two pipes 2 and 3.

[0077] In the Fig. 12 bis 14 Two pipe connections 1 are shown at a pipe branch, each designed as a tensile-resistant pipe connection. A plastic fitting is designed as a so-called branch 28, which has a straight, continuous pipe section and a branching pipe section. All three ends of the branch 28 are designed as sockets into which a spigot end of a pipe can be inserted, and each has a circumferential bead 4 that forms a groove inside the branch 28 into which a seal can be inserted. In the area of ​​the two pipe connections 1, the branch 28 forms the second pipe 3 in each case. A gusset is formed between the straight, continuous pipe and the pipe branching at an angle to it, in which the adjacent beads 4 are close together. To enable collision-free installation even in this gusset, the retaining rings 6 of the Fig. 7 bis 11 used components that are particularly suitable for this especially confined installation space.

[0078] Out of Fig. 12 It is evident that the two retaining rings 6 intersect each other in the area of ​​a break 25, which enables their installation even in the very narrow space. Because each retaining ring 6 has four breaks 25 distributed around its circumference, each retaining ring 6 can intersect the other retaining ring 6 in four different rotational angle positions, depending on the installation situation. In this way, each retaining ring 6 can be aligned so that its clamping elements 16 are easily accessible, e.g., to apply a screwdriver to the screw heads of the screws 22.

[0079] The retaining rings 6 of the Fig. 12 bis 14 The clamping devices 16 have recesses designed for the rotation-proof reception of hexagonal nuts, but can optionally also accommodate the screw heads of the screws 22. The orientation of the screws 22 used as clamping devices 16 can therefore be selected so that the screw heads are easily accessible, depending on the installation situation of the retaining ring 6. Since the screw heads are round on the outside and have a central force application in the form of an internal hexagon, they can be easily rotated within the recesses to loosen or tighten the clamping devices 16 as desired. Tabs 29 project beyond the screw heads and nuts in the axial direction of the clamping devices 16 and are bent in such a way that both the screw heads and the nuts are secured against axial displacement in their respective recesses and thus held in place.

[0080] The partial rings 15 of the in Fig. 12 The illustrated retaining rings 6 each have two different ends that serve to form a chamber. For this purpose, one of the two ends has a collar 30 which, together with the pipe surfaces, which also serve as chamber walls, creates a receiving space into which the other end of the adjacent partial ring 15, which also forms a wall of the chamber, is inserted. A slot would form between two adjacent partial rings 15 without the collar 30 and would extend radially outwards from the pipe surfaces, as shown in Fig. 9 As can be seen, the opening is closed by the collar 30. The clamping elements 16 each extend through such a chamber and, since they bear against the chamber walls on the outside with considerable pressure, for example with the illustrated screw head and the opposing nut, they seal the bores through which the screws 22 extend, and thus the chamber, and prevent the escape of a sealant from the chamber when the sealing ring 5 or the seal 21 of the pipe connection 1 is created by a potting compound that is injected into the cavity 31 between the retaining ring 6 and the pipe surfaces.

[0081] Fig. 14 shows on a larger scale than Fig. 12 and 13 A look into the gusset. It can be seen that the two retaining rings 6 intersect in the area of ​​their recesses 25, thus enabling assembly in a very confined space. This also applies to the retaining ring of the Fig. 12 bis 14Each of the projections 24 is provided with its own short stiffening rib, which runs longitudinally along the respective projection 24 and ensures the desired contact force of the retaining claws 8 on the respective pipe surface even without a clamping ring 10. Additionally, a clamping ring can also be arranged circumferentially around the outside of the projections 24; in this case, it acts on the retaining claws 8 via the short ribs and the projections 24. In particular, in this case, the short ribs can each have one or two outwardly projecting studs to secure the clamping ring 10 against slippage and to guide it on the respective short rib. Reference symbol:

[0082] 1 Pipe connection 2 First pipe 3 Second pipe 4 Bead 5 Sealing ring 6 Retaining ring 7 Claw section 8 Retaining claw 9 Recess 10 Tension ring 11 Tension screw 12 Pressure piece 14 Retaining rib 15 Partial ring 16 Clamping device 17 Reinforcing rib 18 Shoulder 19 Retaining rib section 20 Support rib 21 Seal 22 Screw 23 Square nut 24 Projection 25 Break 26 Shell surface 27 Filling opening 28 Branch 29 Tab 30 Collar 31 Cavity

Claims

1. Retaining ring (6) which is specified for the production of a high-tensile pipe connection (1) with the following features: • the pipe connection (1) has a first pipe (2) with a tip end which extends into a socket end of a second pipe (3), • the second pipe (3) has a circumferential bead (4), and wherein the retaining ring (6) • is specified, when in use, to engage over the bead (4) of the second pipe (3) such that the retaining ring (6) is secured in form-fitting fashion in the axial direction on the second pipe (3) against pull-off forces, • has a claw portion (7) which is specified, when in use, to extend over the first pipe (2), o and wherein at least one retaining claw (8) which is specified, when in use, to penetrate the surface of the first pipe (2) is arranged in the claw portion (7) such that the first pipe (2) is secured in form-fitting fashion against pull-off forces, • has an inner contour which runs at least partially in a U-shape in an axial direction, o with a first portion which is specified to extend over the first pipe (2), o and with a second portion which is specified to extend over the second pipe (3), ▪ and which has a radially inwardly protruding retaining rib (14), • which is specified to engage behind the bead (4) of the second pipe (3) such that the retaining ring (6) is secured in form-fitting fashion in an axial direction on the second pipe (3) against pull-off forces, • and which has a gap (25) in an axial direction along its circumference, • has a lateral surface (26) which connects the first portion and the retaining rib (14) to each other, • wherein the gap (25) of the retaining rib (14) extends into the lateral surface (26) in such a way that the lateral surface (26) has a gap (25) in a radial direction along its circumference, characterized in that the retaining ring (6) is formed from at least two part-rings (15) which extend in each case over part of the circumference of the retaining ring (6), wherein two neighbouring part-rings (15) of the at least two part-rings (15) are connected to each other by tensioning means (16).

2. Retaining ring (6) according to Claim 1, characterized in that the tensioning means are configured as a tensioning ring (10), and in that the tensioning ring (10), the circumference of which is modifiable, runs around the outside of the claw portion (7), and in that either the retaining claw (8) protrudes outwards via the claw portion (7) or a pressure piece (12) is arranged between the tensioning ring (10) and the retaining claw (8) such that, when the circumference of the tensioning ring (10) is reduced, a radially inwardly acting pressure can be generated at one point on the retaining claw (8).

3. Retaining ring (6) according to Claim 2, characterized in that the pressure piece (12) is configured as an inwardly protruding projection of the tensioning ring (10).

4. Retaining ring (6) according to Claim 2, characterized in that the pressure piece (12) is configured as an outwardly protruding projection of the claw portion (7).

5. Retaining ring (6) according to one of the preceding Claims, characterized in that the claw portion (7) has an indentation (9) which is open radially inwards and into which the retaining claw (8) is inserted.

6. Retaining ring (6) according to one of the preceding Claims, characterized in that the retaining claw (8) has a thread and extends in the axial direction of the first pipe (2).

7. Retaining ring (6) according to Claim 6, characterized in that the retaining claw (8) is configured as a grub screw.

8. Retaining ring (6) according to one of the preceding Claims, characterized in that a plurality of retaining claws (8) are arranged distributed around the circumference of the claw portion (7).

9. Retaining ring (6) according to one of the preceding Claims, characterized in that neighbouring part-rings (15) adjoin each other with two differently configured ends, and one of the two different ends serves to form a chamber such that it has a collar (30) which, together with the pipe surface and the neighbouring part-ring (15), creates a receiving space through which the tensioning means extends to the said neighbouring part-ring.

10. Retaining ring (6) according to one of the preceding Claims, characterized in that each part-ring (15) has a retaining rib portion (19), wherein the part-rings (15) have a first spacing from each other in a pre-mounted arrangement and can move between the first arrangement and a second mounted arrangement in which they have a second spacing from each other which is less than the first spacing and in which they are held together by tensioning means (16), and in that the retaining rib portions (19) in each case extend radially inwards by different amounts in such a way that the retaining rib (14) has a non-circular inner contour and, at the ends of the retaining rib portions (19), where in each case one part-ring (15) is adjacent to another part-ring (25), the retaining rib (14) has a larger internal diameter than at the circumference spaced apart from this end.

11. Retaining ring (6) according to one of the preceding Claims, characterized in that the retaining ring (6) has two gaps (25) in the retaining rib and the lateral surface along its circumference, wherein the two gaps (25) are arranged with a spacing from each other along the circumference of the retaining ring (6).

12. Pipe arrangement, • with two first pipes (2) which in each case have a tip end, • and with two second pipes (3), forming a branch (28), which in each case have a socket end o wherein the second pipes (3) have in each case a circumferential bead (4) at the socket ends, • wherein in each case a tip end of a first pipe (2) extends into each socket end of a second pipe (3), • and with two retaining rings (6), o at least one of which is configured according to one of Claims 1 to 11, o and the retaining ribs (14) of which in each case engage over a bead (4) of the second pipe (3) such that the retaining ring (6) is secured in form-fitting fashion in the axial direction on the second pipe (3) against pull-off forces, • and wherein the two retaining rings (6) are arranged such that they interpenetrate in the region of the gap (25) of at least one of the two retaining rings (6).

13. Pipe arrangement according to Claim 12, characterized in that the second pipe (3) is configured as a double socket which enables in each case one tip end to be received at both of its ends.

14. Pipe arrangement according to Claim 12 or 13, characterized in that the two pipes (2, 3) are made from plastic.

15. Pipe arrangement according to one of Claims 11 to 14, characterized in that the two retaining rings (6) are configured in each case according to one of Claims 1 to 11.