Retaining ring for a fitting and fitting with a retaining ring of this type

Abstract

The invention relates to a retaining ring for a pipe fitting to be externally sealed, comprising several annular elements (4) and several hinge elements (6) for pivotally connecting two respective annular elements (4). The annular elements (4) are designed to hold and / or secure a pipe to be connected, are strip-shaped thanks to the hinge elements (6), and can be flat or laterally open. The retaining ring solves the technical problem of providing a retaining ring that is simplified in production and designed for more flexible use. The invention also relates to a fitting comprising a retaining ring (2).

Description

[0001] The invention relates to a clamping ring for a fitting for a pipe to be sealed from the outside and to a fitting for connecting to a pipe to be sealed from the outside with a clamping ring.

[0002] The relevant technical field for the present invention is the on-site installation of piping systems, in which a piping system consisting of pipe sections and fittings is generally installed to convey and transport a fluid, i.e., a liquid or a gas. A fitting is fundamentally understood to be a connecting piece for a pipeline, and a fitting is most commonly used to connect two or more pipe sections. Accordingly, the fitting preferably has two or more press sections, for example, in the form of press sleeves. The most common fittings include straight connections, changes of direction in the form of pipe bends, reducers, branches such as tees, or crossovers. However, a fitting can also be understood to be a pipe connection of a valve or other component. For example, thermometers or pressure gauges, as valves, only have one connection for a single pipe section.Thus, the fitting of a valve has only one press section to connect a pipe section to the valve.

[0003] Press connections are used to connect pipe sections to fittings and other components. In this process, a press jaw deforms the press section of a fitting radially inwards with the pipe section inserted, creating a permanent and tight, and potentially even inseparable, connection. The fittings can be equipped with a sealing element, such as an O-ring, to ensure the tightness of the connection, or they can be designed with direct contact between the materials of the pipe section and the fitting, for example, a metal-to-metal seal.

[0004] For radial forming of the press section, predominantly radially acting press systems as well as press systems that use radial-axial pressing are suitable, whereby during the pressing process a part of the fitting is axially displaced in order to effect radial forming.

[0005] The previously described piping systems are primarily used for transporting drinking water or heating water, gas for operating a heating system, or industrial gases. In principle, any fluid medium can be transported in these pipelines.

[0006] Press fittings are distinguished by whether a pipe is sealed and fixed from the outside during the pressing process, or whether at least part of the fitting, for example in the form of a support sleeve, stabilizes the pipe to be sealed from the inside. The present invention relates to the type of fitting in which the pipe is sealed and fixed from the outside. This does not fundamentally preclude the possibility of a component of the fitting also being located inside the pipe, but this is generally not the case.

[0007] Materials used for externally sealed pipes include solid materials, particularly metallic materials. Solid plastics are also suitable. Examples of suitable materials include metals such as stainless steels like ferritic steels 1.4520 and 1.4521, austenitic steels like 1.4404, duplex steels like 1.4462, red brass, SiBr, and copper. Solid plastics such as cross-linked polyethylene (PE-X), high-temperature polyethylene (PE-RT), polyvinyl chloride (PVC), and polypropylene (PP) can also be used, provided the wall thickness is appropriate. Furthermore, multilayer composite pipes can be sufficiently rigid for external sealing, for example, by incorporating a thicker aluminum layer. Fiber-reinforced pipes can also be used.

[0008] The described fittings and their components are preferably made of a metal to ensure malleability with sufficient hardness and dimensional stability after forming. Suitable metals include those already mentioned for rigid pipes, such as stainless steels like ferritic steels 1.4520 and 1.4521, austenitic steels like 1.4404, duplex steels like 1.4462, red brass, SiBr, and copper.

[0009] The fittings and their components described can also be made of a non-metallic material or plastic, provided the non-metallic material offers sufficient properties for crimping and permanent connection to pipes. Suitable materials include, for example, the following: cross-linked polyethylene (PE-X), silane-cross-linked polyethylene (PE-Xb) or physically cross-linked polyethylene (PE-Xc), high-temperature polyethylene (PE-RT), polyvinyl chloride (PVC), polypropylene (PP) at appropriate wall thicknesses, polyphenylsulfone (PPSU), polyetheretherketone (PEEK) or polyaryletherketone (PAEK), aliphatic bio-based polyamide (PA410, PA12, PA12-GF30), or polypropylene random copolymer with a modified crystal structure and high temperature resistance (PP-RCT).

[0010] Fittings for connecting to a pipe that needs to be sealed externally can have various designs. Typically, a sealing ring, such as an O-ring, is provided to seal the fitting against the outside of the pipe. Furthermore, retaining elements and / or fixing elements are provided to hold the pipe in the required position relative to the fitting before and after crimping.

[0011] For example, a fitting for connecting to a pipe to be sealed from the outside has a base body, a structure with a stop element formed circumferentially in the base body and projecting inwards, a press sleeve connected to the base body and forming an outer contour, wherein the press sleeve has a chamber directed inwards towards the pipe to be received, a clamping ring arranged in the chamber, wherein the clamping ring is made of a plastic and has a plurality of clamping elements oriented against the extension direction of the pipe to be inserted, and a sealing element arranged in the chamber adjacent to the stop element, wherein the press sleeve is suitable, together with the clamping ring, the clamping elements and the sealing element, to seal the rigid pipe to be connected from the outside.

[0012] The base of the clamping ring is made of plastic and has a closed ring shape. To insert the clamping ring into a fitting or into the undercut chamber of the press sleeve, it must be compressed radially, for which purpose axially extending slots are provided to facilitate compression.

[0013] A problem with the previously described design of the fittings and the clamping rings used is that, firstly, a specific clamping ring must be manufactured for each fitting. Secondly, manufacturing the clamping rings is complex because retaining elements and / or fixing elements must be integrated into the round shape, and numerous slots must be incorporated to ensure flexibility for installation. Furthermore, the arrangement of slots does not provide a continuous contact surface for the O-ring, which can shorten the service life of the connection.

[0014] US Patent 4,119,335 A describes a clamping ring arrangement in the form of an elongated strip with knurled ring elements connected to each other by elastomer elements.

[0015] EP 3 051 199 A1 describes a clamping ring arrangement in ring form with ring elements that are connected to each other by means of connecting elements.

[0016] EP 2 242 947 A1 describes a clamping ring with ring elements, which can be in strip form or as a laterally open ring.

[0017] US 2016 / 053783A1 describes a retaining clamp in the form of a band with ring elements and hinge elements and a locking mechanism, by means of which the connection points of pipelines can be secured.

[0018] JP 2014 190366 A describes a fitting for connecting pipes with a retaining element with ring elements and hinge elements made of different materials.

[0019] US 2012 / 0061956 A1 describes a clamping ring with ring elements and hinge elements, whereby the ring elements can only assume a laterally open ring shape.

[0020] Therefore, the present invention is based on the technical problem of providing a clamping ring and a fitting with such a clamping ring, wherein the manufacture of the clamping ring is simplified and its use is designed to be more flexible.

[0021] The aforementioned technical problem is solved according to the invention by a clamping ring for a fitting for a pipe to be sealed from the outside, comprising a plurality of ring elements and a plurality of hinge elements for pivotably connecting two ring elements each, wherein the ring elements are designed to hold and / or fix a pipe to be inserted, wherein the ring elements have a strip shape by means of the hinge elements, wherein the ring elements can assume a flat shape or a laterally open ring shape, wherein the ring elements connected to each other by means of the hinge elements can be folded from the flat shape into the ring shape, and wherein the ring elements have side surfaces in the azimuthal direction which are designed to taper inwards towards each other at least partially in the radial direction.

[0022] The technical problem described above is also solved according to the invention by a fitting for connecting to a pipe to be sealed from the outside, comprising a base body, a stop element formed circumferentially in the base body and projecting inwards, a press sleeve connected to the base body, wherein the press sleeve has a chamber directed inwards towards the pipe to be received, a clamping ring arranged in the chamber, wherein the clamping ring is made of a plastic and has a plurality of cutting elements oriented against the extension direction of the pipe to be inserted, and a sealing element arranged in the chamber adjacent to the stop element, wherein the press sleeve is suitable, together with the clamping ring, the cutting elements and the sealing element, to seal the pipe to be connected from the outside, wherein the clamping ring is designed in one of the embodiments described above and below.

[0023] The clamping ring is advantageously manufactured as a flat product, with the individual ring elements movably connected to one another by means of hinge elements. The ring elements thus form individual segments of the clamping ring. The term "flat product" or "flat" means that the ring elements can be formed into an elongated, flat, and strip-shaped form by the hinge elements and that the ring elements can lie essentially flat on a surface.

[0024] The hinge elements are preferably designed as film hinges integral with the ring elements, so that the clamping ring is in a single, one-piece form. Therefore, the clamping ring can preferably be manufactured as a continuous profile using a plastic extrusion process. Furthermore, the design as a flat, strip-shaped clamping ring facilitates the assembly of additional elements such as cutting elements, which can be integrated more easily after the strip has been manufactured than if the clamping ring were in ring form.

[0025] The ring elements, connected by hinges, can be folded from a flat shape into a ring shape. For installation in a fitting, the clamping ring is cut to a predetermined length and then inserted into the fitting in an open ring shape, similar to a C-shape. Due to its special design with hinges and the resulting elasticity, the clamping ring can be easily bent radially inwards for installation. If necessary, the free ends of the clamping ring can overlap during installation and unfold into a ring shape when inserted into the chamber of the press sleeve. This facilitates assembly, particularly in fittings with small diameters.

[0026] When the fitting is radially pressed using a pressing tool, the hinge elements and the adjacent areas of the ring elements form the deformation zones. These deformation zones are therefore evenly and, if necessary, even symmetrically distributed in the circumferential direction. During the pressing process, the deformation zones ensure a uniform force application in the azimuthal direction and, in particular, restrict or even completely prevent tangential displacement of the ring elements. Especially in the subsequently described configuration of the ring element as a fixing element with a cutting element, it is advantageous that tangential movement of the cutting element is restricted or prevented.

[0027] Furthermore, the compressed hinge elements together with the ring elements create a continuous sealing contact surface in the compressed state, thus ensuring the positioning and securing of the sealing element.

[0028] The ring elements described above preferably consist of one of the following materials: cross-linked polyethylene (PE-X), silane-cross-linked polyethylene (PE-Xb) or physically cross-linked polyethylene (PE-Xc), polypropylene (PP), polyphenylsulfone (PPSU), polyetheretherketone (PEEK) or polyaryletherketone (PAEK), aliphatic bio-based polyamide (PA410, PA12, PA12-GF30) or polypropylene random copolymer with modified crystal structure and increased temperature resistance (PP-RCT).

[0029] Preferably, the ring elements have a partially cylindrical outer surface. This allows the ring elements to conform, at least partially, to the cylindrical shape of the fitting in the chamber of the press sleeve. In their flat, strip-like form, the ring elements can therefore rest on a flat surface with a portion of their partially cylindrical outer surface.

[0030] Furthermore, the ring elements have azimuthal side surfaces that, at least in sections, taper radially inwards towards each other. This allows the ring elements, together with the connecting hinge element, to form a V-groove between them. This V-groove facilitates easier circular arrangement of the ring elements. Additionally, the extra space between the ring elements provides a volume that can be filled with material from the ring elements during pressing. This results in a uniform distribution of the pressing force, which is continuously exerted from the press sleeve via the clamping ring onto the outside of the pipe.

[0031] In a further preferred embodiment, the ring elements have a predetermined azimuthal length, so that by cutting the strip of hinge elements into strips with at least two different numbers of ring elements, it is possible to use at least two clamping rings for fittings with at least two different standard diameters. This allows for variable nominal diameter use of the clamping ring by cutting it to different lengths. Since the clamping ring should ideally fill a complete circle within the fitting, this ensures, firstly, a continuous contact surface for the sealing element and, secondly, a secure fit of the clamping ring before crimping, thus preventing, for example, it from falling out during transport.

[0032] To enable the multiple use of a previously described clamping ring, the division of the clamping ring is chosen so that the full circumference can be achieved with two or more nominal sizes.

[0033] Furthermore, the ring elements can have a sealing seat at the end facing the seal to be inserted. The sealing seat is preferably realized by an axially projecting retaining element that radially limits the space enclosed by the ring element inwards, thereby restricting the seal's freedom of movement. However, the ring element can also be partially circular and restrict the seal's freedom of movement solely through axial contact with the seal.

[0034] The seal seat improves seal protection by limiting or preventing axial displacement of the seal during fitting compression. Furthermore, the seal seat prevents displacement due to axial forces during pipe insertion. Additionally, the seal's position is secured against displacement even in the uncompressed state when pressure differentials occur, specifically when pressure differentials cause the seal to be drawn in axially.

[0035] The ring elements of the clamping ring can perform the same or different functions and therefore be designed differently. The different functions can be realized alternately or in some other way by the adjacent ring elements.

[0036] In a first preferred embodiment, the ring elements are at least partially designed as retaining elements and have radially inwardly directed, preferably elastic, guide elements for centering and, if necessary, holding a pipe to be inserted. Thus, the retaining elements serve, firstly, to center the pipe when it is inserted into a fitting and the clamping ring arranged therein, and secondly, after insertion and before crimping the fitting, to hold the pipe with defined assembly forces.

[0037] Centering the pipe during insertion into the fitting is preferably improved by providing at least two radially different inwardly projecting guide elements in the axial direction. This results in a first and a second centering point during pipe insertion. The first guide element, distal to the fitting, can project less inward than the proximal guide element, thus ensuring good guidance to the correct position for crimping, especially for pipes inserted at an angle. Furthermore, the various guide elements hold the inserted pipe in place after assembly and before crimping.

[0038] The design of the guide elements results in defined assembly forces and therefore also in improved tactile control when inserting a pipe into the fitting, especially with a two-stage design of two guide elements projecting to different distances inwards. The user can more precisely check by touch whether the pipe has been inserted correctly and far enough.

[0039] The geometry of the guide elements with defined material thickness and material properties allows for a consistent assembly and pipe holding force to be achieved regardless of the pipe's tolerances.

[0040] Due to their centering function, the guide elements, particularly in conjunction with the seal seat described above for more precise seal positioning, ensure that the outer surface of the pipe comes into minimal or preferably no contact with the inner surface of the seal during insertion. This reduces the risk of seal damage and allows for low insertion forces even without the use of lubricants such as silicone oil. Therefore, the use of seals without paint-wetting impairment substances (LABS-free) and without silicone is possible.

[0041] The described design also improves the functionality of a deliberately leaky pipe-seal assembly in the unpressed state, as it enhances the positioning and retention of the pipe relative to the seal. For example, if the seal has a sufficiently larger inner diameter than the outer diameter of the pipe, a deliberate leak can be achieved and ensured in the unpressed state.

[0042] As an alternative to the retaining elements, the ring elements can also be designed, at least partially, as fixing elements, each of which has at least one cutting element for securing a pipe to be inserted. After insertion and after the fitting has been crimped, the fixing elements secure the pipe against being pulled out of the fitting.

[0043] Preferably, the cutting elements are located on the inside of the pipe along a linear area, in particular a cutting edge, and on the outside of the chamber of the press sleeve along a planar area. This allows the radially inward force applied during the pressing of the fitting to be effectively converted into cutting the cutting element into the wall of the pipe.

[0044] In a preferred embodiment of the clamping ring, the fixing elements have protective elements arranged circumferentially next to the cutting elements, with the protective elements projecting further inwards in the radial direction than the cutting elements. This protects the pipe from contact with the cutting elements during insertion and before crimping, thus largely preventing damage to the pipe surface at unwanted points. The protective elements therefore function similarly to the guide elements described above.

[0045] In a particularly preferred embodiment, the clamping ring is designed with both retaining elements and fixing elements, such that some of the ring elements are designed as retaining elements and some as fixing elements. Preferably, the retaining elements and the fixing elements are arranged evenly distributed around the circumference to achieve the most symmetrical arrangement possible.

[0046] Furthermore, it is preferred that the number of retaining elements is greater than or equal to the number of fixing elements; in particular, the ratio of retaining elements to fixing elements is 1:1 or 2:1. A larger number of fixing elements is also possible, with only 3-5 retaining elements and otherwise only fixing elements.

[0047] The previously described guide elements for the retaining elements and the protective elements for the fixing elements can contribute to fixing in addition to the cutting elements by also penetrating the pipe wall during crimping. Therefore, the number of fixing elements can be lower than the number of retaining elements.

[0048] The invention will now be explained using exemplary embodiments with reference to the drawing. The drawing shows... Fig. 1-4 shows a first embodiment of a clamping ring according to the invention, Fig. 5-8 shows a second embodiment of a clamping ring according to the invention, and Fig. 9a-9c shows an embodiment of a fitting with an inserted clamping ring without and with an inserted pipe, Fig. 10a-10 shows a schematic representation of a fitting with a fitting according to the invention before and after radial crimping.

[0049] In the following description of the various embodiments according to the invention, components and elements with the same function and mode of operation are provided with the same reference numerals, even if the components and elements may differ in their dimensions or shape in the various embodiments.

[0050] The Fig. 1 bis 4 show a first embodiment of a clamping ring 2 in different views and positions.

[0051] The clamping ring 2 is suitable for a fitting for an externally sealed pipe, which is described below. The clamping ring 2 has a plurality of ring elements 4, each of which is pivotably connected to one another by hinge elements 6. The ring elements 4 serve to hold and / or fix an inserted pipe.

[0052] Furthermore, the ring elements 4 have a striped shape by means of the hinge elements 6, as can be seen in particular from the Fig. 1a and 2 This results in the ring elements 4 being able to have a flat shape as shown in the following example. Fig. 1a and 2 assume, where "flat" essentially means that the ring elements 4 can rest on a surface.

[0053] Secondly, the ring elements 4 can also form a laterally open ring shape as shown in the image provided by means of the hinge elements 6. Fig. 3 , 4a und 4b Assume. The clamping ring 2 has a C-shape open on one side in its ring form.

[0054] During the production of the clamping ring 2 as a continuous product, for example as a product of a plastic extrusion process, the flat arrangement has the advantage that the ring elements 4 can be easily fitted with further elements without a ring shape leading to complex process steps.

[0055] As can be seen from the Fig. 1 bis 4 As a result, the ring elements 4 have a partially cylindrical outer surface 8, which is adapted to the cylindrical shape of the fitting or the chamber of the associated press sleeve. This allows the clamping ring to bear against the fitting, at least in sections. In the flat shape of the clamping ring 2, the partially cylindrical outer surfaces then rest in sections on a substrate.

[0056] Furthermore, the ring elements 4 have side surfaces 10 in the azimuthal direction which, at least in sections, taper inwards towards each other in a radial direction. This, together with the hinge element 6, forms V-grooves 12 between the ring elements 4. Fig. 1a The V-grooves 12 are relatively wide and clearly visible in the elongated flat shape of the clamping ring 2, while in Fig. 4a , the V-grooves 12 in the curved ring shape of the clamping ring 2 are narrower, but still present.

[0057] The ring elements 4 have a predetermined azimuthal length, so that by cutting the strip at hinge elements 6 into strips with at least two different numbers of ring elements 4, it is possible to produce at least two clamping rings 2 for fittings with at least two different standard diameters. Thus, sections of varying lengths can be cut from the continuously manufactured strand to serve as clamping rings 2, which are then bent and suitable for fittings with different nominal diameters. This feature is particularly advantageous with regard to manufacturing efficiency.

[0058] The following values ​​are given as a possible example: Nominal size NW28: Inner diameter D=35mm and circumference=109.96 mm (equal to the length of the clamping ring). Nominal size NW35: Inner diameter D=42mm and circumference=131.95 mm (equal to the length of the clamping ring). Therefore, with a length of 11 mm per ring element, 10 elements = 110 mm can be used for nominal size NW28 and 12 elements = 132 mm for nominal size NW35.

[0059] The ring elements 4 further feature a sealing seat 14 at the end facing the seal to be inserted, which is formed by an axially projecting retaining element 16. The sealing seat 14 secures the position of the seal within a fitting both before and after the fitting is crimped.

[0060] As can already be seen directly from Fig. 1a The result is that the ring elements 4 are shaped differently.

[0061] Firstly, the ring elements 4 are partially designed as retaining elements 18 and have radially inwardly directed elastic guide elements 20 for centering and, if necessary, holding a pipe to be inserted. The guide elements 20 are designed to achieve defined assembly forces and an improved pipe retention function.

[0062] The guide elements 20 are according to Fig. 1a und 1b The guide elements 20 are formed by a three-sided recess 22 formed in the material of the retaining element 18 and are thus elastically resilient. Radially inward, the guide elements 20 have projecting wedges 24 that bear against the tube to be inserted and guide it, as shown in Fig. 1c can be seen.

[0063] Guide elements 26, projecting less radially inwards, are axially offset from the guide element 20. Thus, when a pipe is inserted (into Fig. 1c (Coming from the right) a first centering is achieved by the guide element 26 and a second centering by the guide element 20 with the wedge 24 or wedges 24. In particular, angled pipes are centered by these guides, which have different prominences, and optimally positioned in the fitting. The distal guide element 26 thus projects less far inwards than the proximal guide element 20 from the perspective of the fitting. When the pipe is fully inserted, the guide elements 20 and 26 hold the inserted pipe.

[0064] As an alternative to the retaining elements 18, another part of the ring elements 4 is designed as fixing elements 28 and each has at least one cutting element 30 for fixing an inserted tube, as shown in Fig. 1f is shown. For this purpose, the fixing element 28 has a [feature] in the Fig. 1a, 1b , 1d und 1e The recess 31 shown, into which the cutting element 30 is inserted, is opened. Fig. 1a, 1b , 1d und 1e The fixing element 28 is without the cutting element 30 and in Fig. 1f shown with cutting element 30. The cutting element 30 preferably consists of a metal and secures an inserted pipe after pressing before the pipe is pulled out of the fitting.

[0065] The depicted fixing elements 28 also have protective elements 32 arranged circumferentially next to the cutting element 30, which project further inwards in the radial direction than the cutting elements 30. The protective elements 32 thus protect the pipe from unintentional surface damage during insertion and before crimping.

[0066] As can be seen from Fig. 1a In the embodiment 1b, as well as 2 to 4a and 4b, some of the ring elements 4 are designed as retaining elements 18 and some of the ring elements 4 as fixing elements 28. The retaining elements 18 and the fixing elements 28 alternate, so that they are evenly distributed around the circumference. In this embodiment, the number of retaining elements 18 is equal to the number of fixing elements 28.

[0067] As in the Fig. 3 and 4a As shown, the strip of the clamping ring 2 is bent into a round clamping ring 2, with its side ends forming an open point at the location marked with arrow A.

[0068] In the Fig. 5a bis 5f Figures 6 to 8a and 8b show a second embodiment which, in contrast to the first embodiment, is designed for smaller nominal diameters of the pipes to be joined. Therefore, the individual ring elements 4 are smaller, but have the same or identical functionalities.

[0069] Therefore, only the differences will be explained below, and otherwise reference is made to the description of the first embodiment.

[0070] In Fig. 6 The flat clamping ring 2 is shown, in which there are twice as many retaining elements 18 as fixing elements 28. Thus, the sequence consists of two retaining elements 18 and one fixing element 28. This design has proven advantageous for smaller nominal diameters, as fewer pull-out forces need to be compensated by the fixing elements 28 than is the case with the first embodiment for larger nominal diameters.

[0071] As can be seen further from the Fig. 5b and 5c As a result, the guide element 20 is not free-floating, but the elasticity of the guide element 20 is adjusted and ensured by a reduction in material through a recess 25.

[0072] The Fig. 9a bis 9c Figure 1 shows an embodiment of a fitting 40 for connecting to a pipe 42 to be sealed from the outside. The fitting 40 has a base body 44 and a stop element 46 formed circumferentially in the base body 44 and projecting inwards. Furthermore, a forming press sleeve 48 connected to the base body 44 is provided, wherein the press sleeve 48 has a chamber 50 directed inwards towards the pipe 42 to be received.

[0073] In chamber 50 is the one in the Fig. 1 bis 4 The clamping ring 2 shown is arranged. As described, the clamping ring 2 is made of a plastic and has a plurality of cutting elements 30 oriented against the extension direction of the tube 42 to be inserted. In the chamber 50, a sealing element 52, which in this case is designed as an O-ring, is arranged adjacent to the stop element 46.

[0074] The press sleeve 48 is suitable, together with the clamping ring 2, the cutting elements 30 and the sealing element 52, to seal and fix the pipe 42 to be joined from the outside.

[0075] Fig. 9a Figure 40 shows a cross-section through the retaining elements 18 arranged at the top and bottom of chamber 50. The upper cross-section shows a retaining element 18, and the lower cross-section shows a fixing element 28. Fig. 9b shows fitting 40 with pipe 42 inserted in the unpressed state. After Fig. 9b As explained above, the guide elements 20, 24 and 26 of the retaining element 18 (shown above) hold and center the pipe 42 during insertion and before pressing. Fig. 9c Figure 40 then shows the fitting 40 in the pressed state, which is produced by the pressing tool 60, with the guide elements 20, 24 and 26 lying close to the surface of the pipe 42 and thus contributing to fixing and holding the pipe 42.

[0076] The functionality of the fixing element 28 is described in the Fig. 9a bis 9c shown in cross-section below. On the one hand, the protective elements 32 protect the surface of the pipe 42 from damage by the cutting elements 30 during insertion and in the unpressed state, as Fig. 9b shows. On the other hand, the integrated cutting elements 30 are after pressing according to Fig. 9c have penetrated the material of the pipe 42 and fix the pipe 42 in the fitting 40.

[0077] The Fig. 10a and 10b Each figure shows a cross-section of the fitting 40 in the area of ​​the press sleeve 48 with chamber 50. In the unpressed state, according to Fig. 10a The clamping ring 2 is arranged inside the chamber 50, and the ring elements 4, in the form of alternating retaining elements 18 and fixing elements 28, abut the inside of the chamber 50. The guide elements 20 abut the outside of the tube 42, while the cutting elements 30 are spaced apart from the tube. This space is created and maintained by the protective elements 32 described above (not shown in this cross-section) as well as by the guide elements 20 of the adjacent retaining elements 18.

[0078] Fig. 10b shows the pressed state, in which a pressing tool 60 (not shown here) is used. Fig. 9cThe dashed lines indicate that the press sleeve 48 has been radially deformed inwards. The reduction in diameter leads, on the one hand, to a reduction in the distance between the retaining elements 18 and the fixing elements 28, which now lie against each other, and on the other hand, to the penetration of the cutting elements 30 into the radially inwardly deformed wall of the double-layered tube 42. This fixes the tube 42 within the fitting 40 and secures it against being pulled out or pushed out and against axial rotation.

Claims

1. Clamping ring for a fitting for a pipe to be sealed from the outside, - with a plurality of ring elements (4), - with a plurality of hinge elements (6) for pivotably connecting two ring elements (4) in each case, - wherein the ring elements (4) are designed to hold and / or fix a pipe to be inserted, - wherein the ring elements (4) have a strip shape by means of the hinge elements (6), - wherein the ring elements (4) can have a flat shape or a laterally open ring shape, wherein the ring elements (4) connected to each other by means of the hinge elements (6) can be folded from the flat shape into the ring shape, and - wherein the ring elements (4) have lateral surfaces (10) in the azimuthal direction, which are designed to taper inwards towards each other at least in sections in the radial direction.

2. Clamping ring according to claim 1, characterised in that the ring elements (4) have a part-cylindrical outer surface (8).

3. Clamping ring according to claim 1 or 2, characterised in that, the ring elements (4) have a predetermined azimuthal length, so that, by cutting the strip at hinge elements (6) into strips with at least two different numbers of ring elements (4), at least two clamping rings for fittings with at least two different nominal widths are possible.

4. Clamping ring according to one of claims 1 to 3, characterised in that, the ring elements (4) have a seal seat (14) at the end facing a seal to be inserted.

5. Clamping ring according to one of claims 1 to 4, characterised in that, - the ring elements (4) are at least partially designed as retaining elements (18), and - that the retaining elements (18) have radially inwardly directed, preferably elastically designed guiding elements (20, 24, 26) for centring and, if necessary, holding a pipe to be inserted.

6. Clamping ring according to claim 5, characterised in that, at least two guiding elements (20, 24, 26) projecting radially inwards to different extents are formed one behind the other in the axial direction.

7. Clamping ring according to one of claims 1 to 6, characterised in that, - the ring elements (4) are at least partially designed as fixing elements (28), and - that the fixing elements (28) each have at least one cutting element (30) for fixing a pipe to be inserted.

8. Clamping ring according to claim 7, characterised in that, the fixing elements (28) have protective elements (32) arranged next to the cutting elements (30) in the circumferential direction, the protective elements (32) projecting further inwards in the radial direction than the cutting elements (30).

9. Clamping ring according to one of claims 1 to 8, characterised in that some of the ring elements (4) are designed as retaining elements (18) and some of the ring elements (4) are designed as fixing elements (28).

10. Fitting for connecting to a pipe (42) to be sealed from the outside, - with a base body (44), - with a stop element (46) formed circumferentially in the base body (44) and projecting inwards, - with a press sleeve (48) connected to the base body (44), wherein the press sleeve (48) has a chamber (50) directed inwards towards the pipe (42) to be received, - with a clamping ring (2) arranged in the chamber (50), wherein the clamping ring (2) consists of a plastic and has a plurality of cutting elements (30) aligned counter to the direction in which the pipe (42) to be inserted is pulled out, and - with a sealing element (52) arranged in the chamber (50) adjacent to the stop element (46), - wherein the press sleeve (48) is suitable, together with the clamping ring (2), the cutting elements (30) and the sealing element (52), for sealing the pipe (42) to be connected from the outside, characterised in that - the clamping ring (2) is designed according to one of claims 1 to 9.

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