Fitting with fastening element and method for producing a tight connection

Abstract

Fitting (2) for creating a tight connection with a workpiece (4), - with at least one pressing area (6), - wherein at least one sealing element (10) and at least one fastening element (12) are arranged in the pressing area (6), - wherein the fastening element (12) has at least one cutting element (14) made of a metal, - wherein the fastening element (12) has at least one holding element (16) which consists of a plastic, and - wherein the holding element (16) holds the at least one cutting element (14), characterized in - that the holding element (16) and the at least one cutting element (14) are connected to one another by a force fit, a form fit and / or a material fit, - that the fastening element (12) is annular and has a plurality of cutting elements (14) which are arranged distributed along the circumference of the fastening element (12), and - that the cutting elements (14) have cutting edges (26) arranged at a distance from the sealing element (10).

Description

The invention relates to a fitting for producing a tight connection to a workpiece, having at least one pressing region, wherein at least one sealing element and at least one fastening element are arranged in the pressing region, wherein the fastening element has at least one cutting element made of a metal, wherein the fastening element has at least one holding element which consists of a plastic, and wherein the holding element holds the at least one cutting element. The invention further relates to a method for producing a tight connection between a fitting and a workpiece, in which at least one sealing element and at least one fastening element are arranged in a pressing region of a fitting. The invention further relates to a tight connection between a fitting and a workpiece.Fittings of the type mentioned at the beginning are used in the prior art inter alia for producing a tight connection in pipe technology and in steel construction, in particular for guiding fluids or gases in pipes and their connections. The fitting is pressed with a workpiece, for example a pipe or a fitting, and a tight, permanent connection is thereby created. The connection can also be non-detachable, i.e. not be separable again without destroying the workpiece or the fitting.A fitting of the generic type has at least one sealing element and a fastening element. In this case, the sealing of the connection to be produced is effected by the sealing element, which consists, for example, of an elastic material and is brought into tight contact with the fitting and the workpiece. The fastening element serves for mechanically fixing the connection and prevents an undesired release of the connection. The fastening element usually consists of a hard, non-elastic material and enters into a frictional connection or form-fit with the workpiece, in particular by pressing or cutting into the workpiece. Such a configuration of a fitting is also particularly suitable for large pipe diameters.EP 0 922 896 A1 and DE 102 07 201 A1 disclose fittings which have cutting elements and sealing elements which are arranged in particular in two different sections on an inner circumferential surface of the fitting.Furthermore, EP 1 593 899 A1 and WO 2010 / 089 188 A1 describe fittings in which the cutting element and the sealing element are arranged together in a pressing section. The cutting element and the sealing element are separated by an intermediate separating ring. US 2011 / 0 049 875 A1 discloses a further press fitting, wherein a gripping element and a sealing element are arranged jointly in a recess in the fitting base body. Optionally, a separating element is also provided.EP 1 593 898 A1 further discloses a sealing element for a fitting made of an elastic material, wherein cutting elements are incorporated inside the sealing element.DE 20 2011 050 785 U1 describes an arrangement with a threaded connection for pipes. In this case, a metallic claw ring is provided with an annular section and movable tongues distributed over the circumference.DE 101 25 304 C1 relates to a pipe connection with a metallic press fitting, wherein a claw element is arranged on the inside of a cylindrically formed section of the fitting. The claw element can be fastened to the fitting by means of spot welding, adhesive bonding or riveting.EP 2 746 637 A1 relates to a clamping sleeve for a hose coupling with a hose clamping device. The clamping sleeve has holding elements in the non-sealing region, which enter the hose jacket.EP 2 366 933 A1 relates to a termination piece for metal pipes with an annular sealing element and a resilient claw element for axial securing.The object of the present invention is to provide a fitting and a method for producing a tight connection to a workpiece, with which the structure and the use of the fitting are further simplified and at the same time the connection to be produced is improved. A tight connection between a fitting according to the invention and a workpiece is also described.The above-mentioned object is achieved according to a first teaching relating to a fitting in that the holding element and the at least one cutting element are connected to one another by a frictional connection, positive connection and / or material connection, in that the fastening element is of annular design and has a plurality of cutting elements which are arranged distributed along the circumference of the fastening element, and in that the cutting elements have cutting elements arranged at a distance from the sealing element.Because the fastening element has at least one cutting element made of a metal and at least one holding element made of a plastic, the at least one cutting element can be arranged according to the requirements of a pressing operation. The at least one cutting element or the cutting elements are held by the holding element, whereby the cutting elements can be freely arranged in the pressing region of the fitting without the cutting elements having to be designed in such a way that they remain at a specific position independently. The fastening element of the fitting thus has a greater freedom of design and also flexibility in use compared to conventional fittings.The holding element is made of a plastic. By using a plastic at least as part of the fastening element, the production costs are reduced compared to a fastening element which is made entirely of a hard material, in particular metal, since a lower material outlay is produced. Thus, individual, smaller and simply constructed cutting elements made of a hard material, in particular metal, can be used, which are distributed, for example, along a circumference of a circular cross section of a holding element. The at least one cutting element is then held in particular by an annular holding element. In contrast to fastening elements which consist entirely of a hard material, in particular metal, the plastic of the holding element is easier to shape and process, which in turn lowers the production costs of the fitting. Preferably, the holding element is made entirely of plastic.In addition, the design possibilities of the fastening element are improved. The plastic used for the holding element is preferably a hard plastic which deforms only insignificantly under the pressing forces occurring during a pressing operation. The holding element can thus be configured such that the transmission of the pressing forces to the at least one cutting element is promoted and supported by the holding element. As a result, the pressing force acting through the at least one cutting element can be increased or set in a targeted manner, which leads to a better pressing of the at least one cutting element into the material of the workpiece to be pressed and thus overall to a better pressing result.The holding element can thus hold the at least one cutting element in an advantageous position during the pressing and support the pressing or cutting of the at least one cutting element into the workpiece.The holding element and the at least one cutting element are connected to one another. By connecting the holding element and the cutting element, the handling and production of the fitting is facilitated, since fewer parts have to be taken into account. In addition, a connection of the holding element and the cutting element is advantageous for supporting the cutting process of the cutting element by the holding element, in particular if such a connection has no play. A connection between the holding element and the at least one cutting element is effected by a frictional connection, positive connection and / or material connection.For example, the holding element can be of annular design and at least one cutting element is connected to the holding element along the circumference in a force fit. As a result, cutting elements can be designed in a particularly simple manner, for example from a bent metal sheet. Such cutting elements can be clamp-shaped or U-shaped and extend in the radial or axial direction of an annular holding element.For example, an annular holding element can have at least one recess along the circumference, in which at least one cutting element is arranged. This can provide improved frictional engagement between the elements and also provide an annular fastener having substantially uniform outer and inner circumferential surfaces. The recesses can also have a profile, by means of which a positive fit with the cutting elements is produced.The holding element and the cutting element can likewise be connected by a material closure, for example by an adhesive bond or welding. The at least one cutting element can be connected to the holding element in a materially integral manner by injection molding or extrusion of the plastic of the holding element.In particular, the fastening element is embodied in one piece and has a frictional connection, positive connection or material connection between the at least one cutting element and the holding element. This further reduces the number of parts of the fitting and thus simplifies production and handling.In a further embodiment of the fitting, the fastening element is in direct contact with the sealing element. Direct contact between sealing element and a cutting element may be problematic, since the sealing element may be mechanically damaged during a pressing operation and the connection may even leak. For this reason, recourse is often made to arranging a separating ring, which in particular consists of plastic, between the sealing element and the cutting element.With the fastening element which has a holding element, the use of a separating ring can be dispensed with. In particular, the sealing element is in direct contact with the holding element, wherein the at least one cutting element is held at a distance from the sealing element. The holding element can thus simultaneously fulfil the function of the separating ring. Preferably, the section of the holding element which is in contact with the sealing ring is made of plastic. Thus, an impairment of the sealing element by the fastening element during pressing can be avoided in a simple manner.In a configuration of the fitting that is not according to the invention, however, the at least one cutting element has an annular element which is in direct contact with the sealing element. The contact between the sealing element and an annular portion of the at least one cutting element can improve the tightness of the connection to be produced.In a further embodiment of the fitting, at least one additional separating element is provided, which is arranged between the sealing element and the fastening element. The separating ring can in particular protect the sealing element from being impaired during the pressing and can further contribute to the tightness.According to the invention, the fastening element is of annular design and has a plurality of cutting elements which are arranged distributed along the circumference of the fastening element. As already described, the material outlay can be reduced with the holding element and, at the same time, the pressing result can be improved. With an annular fastening element, in particular tubular workpieces can be surrounded along the circumference. A plurality of cutting elements, which are arranged distributed along the circumference, can serve for the secure mechanical fixing of the connection.In particular, the cutting elements are distributed at equal distances along the circumference. The cutting elements can furthermore be arranged symmetrically, for example distributed in mirror symmetry.In an alternative not belonging to the invention, at least one annular cutting element can also be provided, wherein the cutting element has individual cutting edges distributed over the circumference. A corresponding holding element can supplement the annular cutting element in such a way that at least a portion of the outer circumferential surface of the fastening element, apart from the cutting edges, is substantially cylindrical.In a further embodiment of the fitting, the holding element consists at least partially of polybutylene terephthalate (PBT), polyoxymethylene (POM), polyamide (PA), polyethylene terephthalate (PET) or polysulfone. In general, thermoplastics with good strength properties and high temperature resistance can be used in reinforced and non-reinforced configurations. These plastics are advantageous in production and processing. At the same time, the materials are hard enough not to deform substantially under the conditions of pressing.In particular with harder materials, the holding element can also transmit pressing forces. In a further embodiment of the fitting, the holding element is configured to transmit a pressing force acting on the pressing section to the at least one cutting element during a pressing of the fitting.In particular, a pressing force exerted on the fitting initially acts on the holding element. The at least one cutting element is held by the holding element in such a way that at least a portion of the pressing force is transmitted to the at least one cutting element, which in turn is pressed at least into the material of the workpiece. By way of the force flow of the pressing force from the fitting via the holding element to the at least one cutting element, the pressing result can be influenced in a targeted manner by way of the configuration of the holding element.In particular, a force deflection can also be carried out on the holding element. For example, a pressing force acting radially on a fitting can be at least partially converted into a force acting axially on the at least one cutting element, so that the at least one cutting element is partially pressed into the workpiece in the axial direction.In a further embodiment of the fitting, a contact region is provided for contact with a workpiece. By using a contact region which is preferably not pressed or is only partially pressed, further stability can be imparted to the connection. In particular, the contact region can hold the workpiece prior to pressing.In the case of tubular workpieces, the inner diameter of the contact region can correspond to the outer diameter of the workpiece or the outer diameter of the contact region can correspond to the inner diameter of the workpiece.In addition, the pressing region can have at least one stop on the side facing away from the contact region. Such a stop can serve in particular to delimit the pressing region and hold the sealing element and optionally the fastening element in its position before pressing. The end of the fitting may be crimped, for example, to provide a stop. Such a flanging can be effected along the entire circumference or in segments.The stop can also be formed by the holding element. This makes it possible to simplify the production of the fitting. For example, flanging of the end of the fitting can be dispensed with.The above-mentioned object is achieved according to a further teaching relating to a method for producing a tight connection between a fitting and a workpiece, in particular a pipe, wherein the fastening element has at least one cutting element made of a hard material, in particular metal and at least one holding element which consists at least partially of a plastic, and wherein the at least one cutting element is held by the holding element, in which a workpiece is brought into contact with the fitting, in which the fitting is pressed at least at the pressing region, in which the sealing element is pressed between the fitting and the workpiece, and in which the at least one cutting element is pressed into the material of the workpiece.The fitting is designed like the fitting described above. As already described above, the at least one cutting element or the cutting elements can be positioned exactly by means of a holding element according to the requirements of a pressing operation and arranged in the fitting. The fastening element of the fitting thus has a greater freedom of design and also flexibility in use compared to conventional fittings.The plastic used for the holding element is preferably a hard plastic which deforms only insignificantly under the pressing forces occurring during a pressing operation. The holding element can thus be configured such that the transmission of the pressing forces to the at least one cutting element is promoted and supported by the holding element. As a result, the pressing force acting through the at least one cutting element can be increased or set, which leads to better pressing or cutting of the at least one cutting element into the material of the workpieces to be pressed and thus to a better pressing result.In one embodiment of the method, the at least one cutting element is additionally also pressed into the material of the fitting. This results in an improved fixing of the connection, since the at least one cutting element connects the workpiece and the fitting on both sides via a positive connection.It is conceivable for some of the cutting elements to cut into the workpiece and for other cutting elements to cut into the fitting. Since the individual cutting elements are held against one another by the holding element, an improved connection is thus also produced.In a further embodiment of the method, during the pressing a pressing force acting on the fitting is transmitted via the holding element to the at least one cutting element. In particular, a pressing force exerted on the fitting initially acts on the holding element. The cutting elements are held by the holding element in such a way that at least a part of the pressing force is transmitted to the cutting elements, which in turn can cut at least into the material of the workpiece.In particular, a force deflection can also be carried out on the holding element. For example, a pressing force acting radially on a fitting can be at least partially converted into a force acting axially on the at least one cutting element, so that the at least one cutting element is pressed or cut partially into the workpiece in the axial direction.In a further embodiment of the method, a frictional connection and / or a positive connection is effected between the holding element and the workpiece. The holding element can be pressed against the workpiece by the pressing of the fitting and further strengthen the connection via a force fit. A positive connection between the holding element and the workpiece is also conceivable, for example via a profiling on the holding element and the workpiece.The above-mentioned object is achieved according to a further teaching relating to a tight connection between a fitting and a workpiece, in particular a pipe, wherein the tight connection is produced in particular by a method described above, with a fitting described above, wherein the sealing element is situated in a tight contact between fitting and workpiece and wherein the at least one cutting element is pressed into the material of the workpiece. In one embodiment of the tight connection, the at least one cutting element is additionally pressed into the material of the fitting.For further configurations and advantages of the method or of the tight connection, reference is also made to the above explanations relating to fitting. The invention is explained in more detail below with reference to the drawings. The drawing shows FIG. 1 a shows a first exemplary embodiment of a fitting with a pipe in the non-pressed state in a sectional view, FIG. 1 bshows the first exemplary embodiment of a fitting with a pipe in the pressed state in a sectional view, FIG. 2 shows an exemplary embodiment of a holding element in a perspective illustration, FIGS. 3a, b, c show embodiments of cutting elements, FIGS. 4 a, b show exemplary embodiments of fastening elements in a perspective view, FIGS. 5 a, b show embodiments of cutting elements not according to the invention in a perspective view, FIG. 6 ashows an embodiment of a fastening element not according to the invention with the cutting element from FIG. 5 bin a perspective view, FIG. 6 bshows an exemplary embodiment of a fitting not according to the invention, having the fastening element from FIG. 6 aand a pipe, FIG. 7 ashows a second exemplary embodiment of a fitting with a tube in a sectional view, FIG. 7 bshows the fastening element from FIG. 7 ain a perspective view, FIG. 8 ashows a third exemplary embodiment of a fitting with a pipe in a sectional view, FIG. 8 bshows the fastening element from FIG. 8 ain a perspective view, FIGS. 9 a, b show further exemplary embodiments of cutting elements in a perspective view, FIG. 10 shows a perspective view of a further exemplary embodiment of a fastening element, FIG. 11 shows a perspective view of a further exemplary embodiment of a fastening element, FIG. 12 shows a perspective view of a further exemplary embodiment of a fastening element, and FIGS. 13 a, b show a system with an embodiment of a fitting and a pressing tool.FIG. 1 ashows a first exemplary embodiment of a fitting 2 with a pipe 4 as a workpiece in the non-pressed state in a sectional view. The fitting 2 is tubular and has a pressing region 6 and a contact region 8. The contact region 8 has an inner diameter which approximately corresponds to the outer diameter of the tube 4, so that the tube 4 can be held in the contact region 8 by means of a contact.In the pressing region 6 of the fitting 2, a sealing element 10 and a fastening element 12 are arranged. The fastening element 12 has metallic cutting elements 14, which are held by a holding element 16 made of a plastic.By means of a pressing tool not shown in FIG. 1, a pressing of the fitting 2 with the pipe 4 can now take place. An embodiment of a suitable pressing tool is explained below in connection with FIGS. 13 a, b. In particular, the pressing portion 6 is applied with a pressing force acting radially inward on the outer circumferential surface and deformed. As a result, a pressing force acts on the sealing element 10 and the fastening element 12.FIG. 1 bshows the first exemplary embodiment of a fitting 2 with a pipe 4 in the pressed state in a sectional view. The sealing element 10, which is made of an elastic material and assumes the shape of an O-ring, for example, is deformed such that it is in a tight contact with the pressing region 6 and the tube 4. By means of the sealing element 10, the produced connection is tight with respect to liquids and / or gases which can be conducted through the tube 4. A mechanical fixing and in particular an insolubilization of the connection is effected via the fastening element 12. The cutting elements 14 are held by the holding element 16. During the pressing operation, pressing forces thus act on the cutting elements 14, so that the cutting elements cut into the material of the tube 4. The connection is thereby mechanically fixed.FIG. 2 shows an exemplary embodiment of a holding element 16 in a perspective illustration. The holding element 16 is of annular configuration and has slots 18, 20 along the circumference. The slots 18, 20 allow easier deformation of the holding element 16 along the circumference, as a result of which pressing forces can also be transmitted in the circumferential direction to cutting elements held by the holding element 16. The slots 18, 20 can also be used as an indicator for the completeness of a pressing operation, for which the slots 18, 20 are visible, for example, from the outside. The width of the slots 18, 20 allows conclusions to be drawn about the circumference of the holding element 16 and thus about the completeness of the pressing operation. The holding element 16 is preferably made at least partially of a hard material that is not substantially deformable by pressing forces, such as polybutylene terephthalate (PBT), polyoxymethylene (POM), polyamide (PA), polyethylene terephthalate (PET) or polysulfone.For the cutting elements not shown in FIG. 2, recesses 22 are provided, which in particular enable a positive connection with the cutting elements. Corresponding embodiments of cutting elements are shown in FIGS. 3 a, b, c. FIGS. 3 a, b show cutting elements 14 which are designed in the form of clamps and can be manufactured, for example, in a simple manner from a sheet metal. In this case, in addition to a clamp-shaped base body 24, which can be connected to a holding element, cutters 26 are provided. The cutting edges 26 can be arranged on one side or on both sides of the base body 24. If the cutting edges 26 are provided on both sides, the cutting element 14 can also cut into the material of the fitting in addition to the material of the workpiece. FIG. 3 cshows a further exemplary embodiment of a cutting element 14, which has cutting edges 26 on both sides.FIGS. 4 a, b show exemplary embodiments of fastening elements 12 in a perspective view with combinations of the holding element 16 from FIG. 2 and the cutting elements from FIGS. 3 b, c. Cutting elements 14 are inserted into the recesses 22 (see FIG. 2 ) of the holding element 16, said cutting elements being distributed along the circumference of the holding element 16.FIG. 4 a shows a fastening element 12 with cutting elements 14 according to the exemplary embodiment from FIG. 3 b. The cutting elements 14 can be clamped onto the holding element 16 and thus enter into a force fit and / or form fit with the holding element 16. A materially joined connection can likewise be provided, for example an adhesive connection.FIG. 4 bfurther shows a fastening element 12 with cutting elements 14 according to the exemplary embodiment from FIG. 3 c. The holding element 16 is only partially shown in FIG. 4 bto illustrate the arrangement of the cutting elements 14. The cutting elements 14 are connected here to the holding element 16 in a materially integral manner, for example via an adhesive bond or by injection molding or extruding the plastic of the holding element 16 onto the cutting elements 14.The cutting elements 14 can be arranged distributed in particular at equal distances and also mirror-symmetrically along the circumference of the holding element 16.By using individual, smaller metal cutting elements 14 in conjunction with a plastic retaining element 16, the material outlay for producing the fitting is reduced. At the same time, the pressing result can be improved by the configuration of the fastening element 12.FIGS. 5 a, b show embodiments of cutting elements 14 not according to the invention in a perspective view. An annular element 28 is provided which consists of metal. The cutting element 14 further comprises cutting portions 30 which adjoin the annular element 28 and comprise cutting edges 26. Annular element 28 and cutting sections 30 are preferably embodied in one piece.The cutters 26 are embodied on both sides in FIG. 5 a, i.e. the cutting element 14 can be used for pressing both into the material of a workpiece and also of the fitting. FIG. 5 bshows a cutting element 14 with cutting edges 26 arranged on one side, which can be pressed into the workpiece.FIG. 6 ashows an embodiment of a fastening element 12 not according to the invention with the embodiment of a cutting element 14 from FIG. 5 bin a perspective view. The cutting element 14 can be connected to the holding element 16 and held therewith. The holding element 16 has recesses 22 in this case in order to receive the cutting sections 30 of the cutting element 14.FIG. 6 bshows an exemplary embodiment, not according to the invention, of a fitting 2 having the fastening element 12 from FIG. 6 aand a pipe 6, which can be connected to the fitting 2. The fitting 2 further comprises a sealing element 10, which can be arranged together with the fastening element 12 in the pressing section 6 of the fitting 2. The sealing element 10 is brought into direct contact with the fastening element 12, in particular with the annular element 28 of the cutting element 14, and a separating ring between the sealing element 10 and the cutting element 14 can thus be dispensed with.FIG. 7 ashows a second exemplary embodiment of a fitting 2 with a pipe 4 in a sectional view. The cutting elements 14 are designed here as clamps of a sharp-edged sheet metal clamped onto an annular holding element 16.The cutting elements 14 have a burr due to their manufacture, which serves as a cutting edge 26 and can in particular still be bent outwards in the radial direction as shown in FIG. 7 a. The cutting elements 14 point with their preferred direction in the axial direction of the holding element 16.The holding element 16 is also designed as a stop and encloses the pressing region 6 at the end facing away from the contact region 8. The holding element 16 thus holds both the cutting element 14 and the sealing element 10 in their position in the fitting 2. optionally a separating ring 32 is also provided between the fastening element 12 and the sealing element 10, which can prevent the sealing element 10 from being mechanically damaged during pressing.FIG. 7 bshows the fastening element 12 from FIG. 7 ain a perspective view for this purpose. The clamp-shaped cutting elements 14 comprise a sharp-edged sheet metal which is clamped in the axial direction around an annular holding element 16. The cutting elements 14 may be distributed along the circumference of the holding element 16 at equal intervals. FIGS. 7 a, b show an embodiment of the fitting 2 which is particularly cost-effective in terms of production.FIG. 8 ashows a third exemplary embodiment of a fitting 2 with a pipe 6 in a sectional view. The cutting elements 14 are arranged here in the radial direction of the holding element 16. If the fitting is pressed radially inward in the pressing section 6, the cutting elements 14, which are held by the retaining ring 16, are pressed into the material of the tube 4.FIG. 8 bshows the corresponding fastening element 12 from FIG. 8 ain a perspective view. The cutting elements 14 may be distributed at equal intervals along the circumference of the holding element 16. To produce the fastening element 12, the cutting elements 14 can be pressed radially into the material of the holding element 16 or introduced by injection molding or extrusion. By the cutting elements 14 having a greater radial extent than the radial wall thickness of the retaining element 16, the fastening element 12 can be used for a compression within a fitting 2.Embodiments of cutting elements 14, which can likewise be used in the embodiment of the fitting 2 or of a fastening element 12, for example from FIGS. 8 a, b, are illustrated in FIGS. 9 a, bin a perspective view. These cutting elements 14 can be arranged on an annular holding element 16 in the radial as well as in the axial direction.FIG. 9 ashows a clamp-shaped cutting element 14 in a U-shape. This U-shape can be pressed into the material of the tube 4. Such a cutting element 14 can be produced, for example, in a simple manner by punching out a metal sheet and subsequent bending.Fig. 9b also shows a clamp-shaped cutting element 14 in a U-shape. In addition, a profile 34 is arranged on the cutting element 14, which profile allows an improved connection to a holding element 16. In addition, the profiling 34 can also be designed such that it is also pressed into the material of the pressing section 6 during pressing in a fitting 2. A corresponding cutting element 14 can likewise be produced by punching out a metal sheet and subsequent bending.FIG. 10 shows a perspective view of a further exemplary embodiment of a fastening element 12. In this case, U-shaped cutting elements 14 corresponding to the exemplary embodiment from FIG. 9 aare distributed along the circumference of a holding element 16. The cutting elements 14 are arranged with their preferred direction in the axial direction of the fastening element. A particularly cost-effective fastening element 12 can thus be provided.FIG. 11 shows a perspective view of a further exemplary embodiment of a fastening element 12, which likewise has U-shaped cutting elements 14. The cutting elements 14 are designed similar to the exemplary embodiment from FIG. 9 band additionally have a profile 34 which can be pressed into the material of a workpiece and optionally into the material of the fitting.FIG. 12 shows a perspective view of a further exemplary embodiment of a fastening element 12. In this case, the cutting elements 14 are alternatively designed as hat profiles. As a result, in particular the contact surface between cutting elements 14 and holding element 16 can be enlarged and a better hold of the cutting elements 14 can be achieved. The material of the holding element 16 can in particular penetrate the cutting elements 14. For example, the cutting element 14 has openings, wherein the material of the holding element 16 engages through the openings.FIG. 13 ashows a side view of a system with an embodiment of a fitting 2 and a pressing tool 36. the pressing tool 36 is suitable here for deforming the pressing region 6 of the fitting 2 and for establishing a tight connection of the fitting 2 to a workpiece.The pressing tool 36 is designed as a pressing ring. The pressing tool 36 has two pressing tool halves 38 a, 38 bwhich are mounted pivotably with respect to one another via a connecting element 40, for example a hinge or joint. The press tool halves 38 a, 38 bhave attachment sections 42 a, 42 bfor a press machine (not shown). By applying a force to the attachment sections 42 a, 42 b, a receiving region 42 formed between the press tool halves 38 a, 38 bcan be narrowed.A fitting 2 arranged in the receiving region 42 as in FIG. 13 acan thus be pressed radially inward by applying a force to the attachment sections 42 a, 42 b.FIG. 13 bshows for clarity a perspective view of the system from FIG. 13 awith an exemplary embodiment of a fitting 2 and a pressing tool 36.The fitting 2 is shown in FIGS. 13 a, bfor clarity without fastening element 12. However, with the system of fitting 2 and pressing tool 36, any desired embodiments of the fastening element 12 described above can be used.

Claims

Fitting (2) for producing a sealed connection to a workpiece (4), - with at least one pressing region (6), - wherein at least one sealing element (10) and at least one fastening element (12) are arranged in the pressing region (6), - wherein the fastening element (12) has at least one cutting element (14) made of a metal, - wherein the fastening element (12) has at least one holding element (16) which consists of a plastic, and - wherein the holding element (16) holds the at least one cutting element (14), characterized - in that the holding element (16) and the at least one cutting element (14) are connected to one another by a frictional connection, a positive connection and / or a material connection, - in that the fastening element (12) is of annular design and has a plurality of cutting elements (14) which are arranged distributed along the circumference of the fastening element (12), and - the cutting elements (14) have cutting edges (26) arranged at a distance from the sealing element (10).Fitting (2) according to claim 1, characterised in that the fastening element (12) is in direct contact with the sealing element (10).Fitting (2) according to Claim 1, characterized in that at least one additional separating element (32) is provided, which is arranged between sealing element (10) and fastening element (12).Fitting (2) according to one of Claims 1 to 3, characterized in that the retaining element (16) consists at least partially of polybutylene terephthalate (PBT), polyoxymethylene (POM), polyamide (PA), polyethylene terephthalate (PET) or polysulfone.Fitting (2) according to one of Claims 1 to 4, characterized in that the retaining element (16) is configured to transmit a pressing force acting on the pressing section (6) to the at least one cutting element (14) when the fitting is pressed.Fitting (2) according to one of Claims 1 to 5, characterized - in that a contact region (8) is provided for contact with a workpiece, and - in that the pressing region (6) has at least one stop on the side facing away from the contact region (8), said stop being formed in particular by the retaining element (16).Method for producing a sealed connection between a fitting (2) and a workpiece (4), - in which at least one sealing element (10) and at least one fastening element (12) are arranged in a pressing region (6) of a fitting, - wherein the fastening element (12) has at least one cutting element (14) made of a metal and at least one holding element (16) which consists of a plastic, - wherein the at least one cutting element (14) is held by the holding element (16), - wherein the holding element (16) and the at least one cutting element (14) are connected to one another by a frictional connection, positive connection and / or material connection, - wherein the fastening element (12) is of annular design and has a plurality of cutting elements (14) which are arranged distributed along the circumference of the fastening element (12), and - wherein the cutting elements (14) have cutting elements (26) arranged at a distance from the sealing element (10), in which a workpiece (4) is brought into contact with the fitting (2), in which the fitting (2) is pressed at least at the pressing region (6), in which the sealing element (10) is pressed between the fitting (2) and the workpiece (4), and in which the at least one cutting element (14) is pressed into the material of the workpiece (4).Method according to claim 7, characterised in that the at least one cutting element (14) is additionally also pressed into the material of the fitting (2).Method according to claim 7 or 8, characterised in that during the pressing a pressing force acting on the fitting (2) is transmitted via the holding element (16) to the at least one cutting element (14).Method according to one of Claims 7 to 9, characterized in that a frictional connection and / or positive connection is effected between the retaining element (16) and the workpiece (4).A tight connection between a fitting (2) and a workpiece (4), wherein the tight connection is produced in particular by a method according to any one of claims 7 to 10, with a fitting (2) according to any one of claims 1 to 6, wherein the sealing element (10) is in a tight contact between fitting (2) and workpiece (4) and wherein the at least one cutting element (14) is pressed into the material of the workpiece (4).The tight connection according to claim 11, characterized in that the at least one cutting element (14) is additionally pressed into the material of the fitting (2).

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