Press fitting for a pipe connection and method for its manufacture

Description

[0001] The invention relates to a press fitting for a pipe connection comprising a fitting body for connecting the press fitting to a pipe and a press sleeve fixed to the fitting body with a substantially cylindrical pressing area.

[0002] Such press fittings are widely known in the art. They enable the simple and time-saving production of pipe connections for a wide variety of applications using a suitable pressing tool. For example, gas and water pipes of different diameters can be manufactured in this way.

[0003] EP 1 933 073 A1 discloses a press fitting for a pipe, in particular a plastic pipe or a pipe made of a plastic-metal composite material, provided with a fitting body having a support body onto which a pipe to be connected can be pushed. Furthermore, the press fitting has a press sleeve having a holding end at which the press sleeve is held on the fitting body. On its peripheral surface, the press sleeve has a pressing area adjoining the holding end, in which a pressing tool acts upon the press sleeve being pressed. At its holding end, the press sleeve has edge recesses open towards the end face of the press sleeve, each edge recess having a boundary edge section opposite the end face of the press sleeve.A plastic ring is located on the outside of the compression sleeve and is secured thereon against movements in the axial direction of the compression sleeve, wherein the plastic ring has at least one axially projecting projection which extends into the pressing area of ​​the compression sleeve and which is secured so that it can be destroyed and / or separated from the plastic ring when the pressing tool acts on the compression sleeve, and wherein the at least one projection has at least one connecting web which projects from the plastic ring and is connected to it and a circumferential web which is connected to the end of the at least one connecting web facing away from the plastic ring and extends in the circumferential direction of the plastic ring to form a recess therein.

[0004] DE 60 306 297 T2 discloses a connecting piece with at least one opening with which an end of a pipe to be connected can be engaged, and which has at least one peripheral region in which the pipe can be fixed after a squeezing process, and which is covered at least in the region of the peripheral region by a sleeve made of plastic, characterized in that the plastic is heat-shrinkable, and the sleeve is designed to break during the squeezing process, wherein the sleeve has at least one weak region around the peripheral region.

[0005] US 5,195,788 relates to an improved insert member for fastening a hose to a nipple by means of a clamp, and in particular to an improved insert member that automatically ensures the correct positioning of the various components and better protection of the hose against damage, combined with a very good holding capacity of the clamp arrangement.

[0006] The present invention is based on the object of further improving such press fittings. In particular, a particularly slim, material- and space-saving design of such a press fitting is to be described. Furthermore, options are to be provided that enable the indication of the compression of such a press connector. Finally, manufacturing methods for producing such press fittings are to be described.

[0007] The invention is defined in the independent claims. Further embodiments and aspects serve to better understand the invention.

[0008] According to a first aspect of the invention, a press fitting for a pipe connection is described, according to claim 1. The press fitting has a fitting body for connecting the press fitting to a pipe and a press sleeve attached to the fitting body, said press sleeve having a substantially cylindrical press region and at least one protruding element. The at least one element delimits the substantially cylindrical press region in the axial direction. The press fitting further has a tubular band, for example made of a plastic film, which surrounds the substantially cylindrical press region of the press sleeve. The tubular band is arranged so as to be rotatable relative to a surface of the press sleeve, is held in the cylindrical press region by the at least one element, and is at least partially destroyed when the press sleeve is pressed with a pressing tool.

[0009] The provision of a tubular band, for example made of plastic film, enables versatile, simple, and particularly space-saving marking of a press fitting. At the same time, such a band, which is arranged so that it can rotate relative to a surface of the press sleeve, can be carried along by the pressing jaws of a pressing tool during a pressing process and at least partially destroyed, which can serve as an indication of successful pressing of the press fitting.

[0010] The twistability of the band can be achieved, for example, by designing and / or arranging the tubular band and / or the compression sleeve in such a way that the static friction between an inner side of the tubular band and the surface of the compression sleeve is lower than the static friction between an outer side of the tubular band and a surface of a pressing jaw of a pressing tool during pressing. This can be achieved, for example, by having the pressing jaw with a relatively rough inner surface and the compression sleeve with a smooth outer surface.

[0011] For example, the surface of the pressing jaws can be roughened and / or the surface of the pressing sleeve can be smoothed, for example, by polishing, tumbling, or electropolishing. Under these circumstances, the banderol could have a uniform surface with the same surface roughness on both sides.

[0012] In at least one embodiment, the outer side of the tubular band has a greater surface roughness than the inner side of the tubular band. The static friction or surface roughness of the band can be influenced, for example, by printing on its inner or outer side, with the printed side having a different surface roughness than the unprinted side. Alternatively or additionally, it is also possible to roughen the outer side of the band, for example, by mechanical methods or the action of plasma or ion beams.

[0013] In at least one embodiment, the inside of the tubular band is additionally printed with a lubricating varnish, which reduces static friction. Printing, in particular, on the inside of the tubular band has the advantage that the information printed on the band is protected from damage before the press fitting is pressed.

[0014] In at least one embodiment, the tubular band is made of a plastic film. Plastic films are lightweight, inexpensive to produce, and insoluble in water, making them ideal for use on construction sites.

[0015] In at least one embodiment, the plastic film of the tubular band comprises a thermoplastic material, and the tubular band is shrunk onto the substantially cylindrical pressing area. Such a configuration enables simple, optionally subsequent, application of the band to the pressing sleeve.

[0016] Suitable materials for the plastic film of the tubular band include pre-stressed or oriented polystyrene (OPS), polyethylene terephthalate (PET), polylactide (PLA), and polyvinyl chloride (PVC). Such plastic films are relatively brittle at normal temperatures and / or have a low coefficient of expansion. This ensures that the plastic material of the band is reliably destroyed during compression.

[0017] The plastic film of the tubular banderol is available in various designs, either as a single-layer or multi-layer plastic film. A single-layer film is particularly cost-effective and easy to handle. By choosing different materials, for example, for the outer and inner sides of a two-layer plastic film, the roughness or static friction can be adjusted as desired. Furthermore, a multi-layer film allows the print on the banderol to be protected from damage on both sides by placing the print between two film layers.

[0018] In at least one embodiment, the plastic film of the tubular banderol has a thickness between 10 and 200 µm, preferably between 35 and 90 µm, for example 40, 45, or 50 µm. In general, the film should be as thin as technically possible.

[0019] In at least one embodiment, the tubular band is made of a paper strip. Paper strips are lightweight, cost-effective, and environmentally friendly in both production and disposal.

[0020] In at least one embodiment, the tubular banderol has no predetermined breaking point and is at least partially destroyed, in particular crushed, solely by the forces generated during compression. This has the advantage that accidental tearing of the film before compression is virtually impossible.

[0021] In at least one alternative embodiment, the tubular band has at least one perforation line, one incision, and / or one recess. By providing such areas serving as predetermined breaking points, particularly reliable destruction of the film can be ensured. At the same time, they allow any air pockets between the film and the press sleeve to escape during production of the press fitting. Furthermore, an axially or helically extending perforation line can also be used to manually remove the tubular band from the press sleeve if necessary, without the need for an additional tool, such as a knife.

[0022] In at least one embodiment, the tubular band covers substantially the entire pressing area. This prevents unevenness between a surface of the pressing tool and the surface of the compression sleeve covered by the band.

[0023] In at least one embodiment, the press sleeve has at least one first viewing window, and the at least one tubular band has a second viewing window corresponding to the first viewing window. The two viewing windows are arranged in such a way that it is possible to determine whether a pipe end has been fully inserted into the press fitting. These features enable manual inspection during the insertion of a pipe before the press fitting is pressed. For example, the tubular band can be designed to be transparent, at least in the area of ​​the second viewing window.

[0024] In an alternative embodiment, the press sleeve has at least one viewing window, and the tubular banderole does not cover the pressing area of ​​the press sleeve, at least in the part where the viewing window is located. Thus, in this embodiment, it is also possible to determine whether a pipe end has been fully inserted into the press fitting without removing the tubular banderole.

[0025] In at least one embodiment, the tubular banderol contains at least one technical specification regarding the type, installation, or use of the press fitting. Such specifications may, for example, relate to the diameter of a pipe to be connected to the fitting, an application for the pipeline, such as use in gas, hot, or cold water installations, or may include information regarding a tool required for pressing, pressing pressure, or other technical features. This allows a technician on site to reliably select the correct press fitting, avoid confusion between pipes and fittings to be connected, and correctly press the press fitting.

[0026] In at least one embodiment, the technical information includes a usage indication and / or diameter indication in the form of a color marking. Alternatively or additionally, the at least one technical information includes a machine-readable marking, in particular a barcode or a two-dimensional data matrix, wherein the machine-readable marking contains a reference to further technical information stored in a data network. Such information is particularly helpful in providing language-independent or internationalizable technical information.

[0027] In at least one embodiment, the press fitting has a retaining ring, wherein the retaining ring is arranged at an end of the press sleeve opposite the protruding guide element and delimits the pressing area in the axial direction. Thus, the pressing area is clearly delimited axially in both directions, which in particular ensures secure positioning of the pressing tool and thus secure pressing of the press sleeve.

[0028] In at least one embodiment, the protruding guide element is arranged at a distal, open end of the compression sleeve for receiving a pipe, and the retaining ring is arranged at a proximal end of the compression sleeve. The compression sleeve is held to the fitting body of the press fitting by means of the retaining ring. Such an arrangement enables simple and quick assembly of the press fitting and precise positioning of a pressing tool.

[0029] In at least one embodiment, the compression sleeve has a circumferential bead or groove in the region of the proximal end, which engages with the retaining ring.

[0030] In at least one embodiment, the retaining ring has at least one window arranged in such a way that it is possible to determine whether a pipe end has been fully inserted into the press fitting. This can provide an additional or alternative means for inspecting an inserted pipe end.

[0031] In at least one embodiment, the retaining ring and / or the protruding element are designed to guide a pressing jaw of a pressing tool. A guiding function for the pressing tool and a holding function for the band are combined in one element.

[0032] In at least one embodiment, the protruding element is designed as a circumferential flange.

[0033] According to a second aspect of the present invention, a manufacturing method for a press fitting, specifically for a press fitting according to the first aspect, is described in claim 12. The manufacturing method comprises the following steps: Applying a tubular band to a substantially cylindrical pressing region of a pressing sleeve having at least one protruding element, wherein the tubular band is arranged such that it can rotate relative to a surface of the pressing sleeve, is held in the substantially cylindrical pressing region by the at least one protruding element, and is at least partially destroyed when the pressing sleeve is pressed with a pressing tool; and securing the pressing sleeve to a fitting body.

[0034] In at least one embodiment, the step of applying the tubular band is performed before the step of securing the compression sleeve to the fitting body. This simplifies the production of prefabricated sleeve assemblies that can be used on different fitting bodies.

[0035] In at least one alternative embodiment, the step of securing the compression sleeve to the fitting body is performed before the step of applying the tubular band. This enables the application of a compression marking according to the invention to already completed press fittings.

[0036] In at least one embodiment, the tubular band is made of a plastic film and comprises a thermoplastic material. The method additionally comprises heating the tubular band so that the plastic film is shrunk onto the substantially cylindrical pressing area, wherein a temperature and / or a duration of the heating is selected such that, after cooling, the tubular band is arranged so that it can be rotated relative to the surface of the pressing sleeve. Using the measures described, the band can be applied to the pressing sleeve easily and mechanically.

[0037] In at least one embodiment, the diameter of the tubular band is selected such that the tubular band can be applied to the substantially cylindrical pressing area via the at least one protruding element before heating, and that the tubular band is held in the substantially cylindrical pressing area by the at least one protruding element after heating. This allows, in particular, subsequent application of the tubular band to a preformed or preassembled pressing sleeve.

[0038] In at least one embodiment, the step of securing the compression sleeve to the fitting body comprises applying a retaining ring to the compression sleeve and connecting the fitting body to the retaining ring. The retaining ring can simultaneously serve as a boundary for the substantially cylindrical compression region.

[0039] For example, the retaining ring can be molded onto the press sleeve or fitting body before the fitting body or press sleeve is locked to the retaining ring. This manufacturing process enables particularly simple and time-saving production and assembly of the press fitting.

[0040] According to one embodiment, the manufacturing method additionally comprises the step of connecting two opposite edges of a carrier material, in particular a plastic film, so that the carrier material forms a tube containing the tubular band. For example, the two opposite edges of a plastic film are glued or welded together.

[0041] According to one embodiment, the tube has a plurality of tubular bands, and the method further comprises the step of singulating the plurality of tubular bands. In this way, a plurality of tubular bands are efficiently produced from a single web of carrier material.

[0042] In at least one embodiment, the manufacturing method additionally comprises the step of printing on at least one side of the carrier material. In this way, a tubular band with printed information can be produced from a flat, printable carrier material. An offset or laser printing process is particularly suitable for this purpose.

[0043] In at least one embodiment, a material of the tubular band, in particular the plastic film, is perforated. This step can optionally be performed before the two opposite edges are joined.

[0044] Further advantageous aspects and embodiments of the present invention are disclosed in the following description of embodiments and the appended patent claims.

[0045] The invention is described in detail below using various embodiments with reference to the attached figures. In these figures: Figures 1A to 1C show a first embodiment of a press fitting according to the invention, Figure 2 shows a second embodiment of a press fitting according to the invention, Figure 3 shows a third embodiment of a press fitting according to the invention, Figures 4A and 4B show different sections of a cross section through the pressing area of ​​a press fitting according to the invention, Figures 5A to 5C show perspective views of a press fitting according to the invention during and after a pressing process, Figures 6A and 6B show different printing templates for bands of press fittings according to the invention, Figure 7 shows a shrinkage curve of a suitable thermoplastic film for producing a band, and Figure 8 shows a flow diagram of a method for producing a press fitting according to the invention.

[0046] In the Figures 1A to 1C different representations of a press fitting 1 according to a first embodiment of the invention are shown. Figure 1Ashows a perspective view of the assembled press fitting 1, Figure 1B shows a top view of the press fitting 1 cut open in the middle, and Figure 1C shows a sectional view along a central cutting plane of the press fitting 1.

[0047] As particularly in the Figures 1B and 1C As can be seen, the press fitting 1 is designed to be particularly slim and material-saving. This is achieved through various features that are described in detail below.

[0048] In the Figures 1A to 1C It can be seen that the press fitting 1 essentially comprises a fitting body 2 for connecting the press fitting 1 with a Figures 1A to 1Cnot shown pipe, for example a metal, plastic or metal-plastic composite pipe, and a press sleeve 3 fixed to the fitting body 2 with a substantially cylindrical pressing area 4. Particularly in the case of metal-plastic composite pipes, it is desirable for mechanical reasons that the pipe is pushed over a part of the fitting body 2. This part of the fitting body 2 serves as a support sleeve when pressing the press sleeve 3. In the exemplary embodiment, the fitting body 2 is designed to be rotationally symmetrical with respect to its longitudinal axis and mirror-symmetrical with respect to a central plane perpendicular thereto, with two opposite connections for producing a straight pipe connection.Depending on the diameter of the press fitting 1 and the fluid to be passed through, the fitting body 2 can be made of a plastic material, such as polyphenylene sulfone (PPSU), or a metal material preferably suitable for drinking water, such as in particular a tinned copper alloy or stainless steel.

[0049] The press sleeve 3 essentially consists of a hollow piece of sheet metal, for example made of stainless steel. The cylindrical press area 4 of the described embodiment is smooth before pressing, i.e., it has no protruding ribs or embossed recesses, and thus contributes to the particularly slim design and material- and resource-saving production of the press fitting 1. In principle, the provision of protruding ribs on the press area 4 is also possible. However, due to the direct action of the pressing tool on a sealing area, contouring of the press sleeve 3 is not necessary. The press area 4 is delimited in the axial direction at the distal end of the press fitting 1 by an outwardly bent flange 5 of the press sleeve 3. At the opposite, proximal end, the press area 4 is delimited by a retaining ring 6.

[0050] In the described embodiment, the retaining ring 6 is a plastic injection-molded part. The retaining ring 6 serves to secure the compression sleeve 3 to the fitting body 2. For this purpose, the compression sleeve 3 has a slightly widened area 7 at its proximal end, which is locked to the retaining ring 6. The retaining ring 6 is further locked to the fitting body 2 via two opposing locking lugs 8 and 9. Slitting or other machining of the compression sleeve 3 is not necessary. If the fitting body 2 and the compression sleeve 3 are made of metal materials, the retaining ring 6 also serves to create a galvanic isolation.

[0051] To seal a fluid-conducting connection between a pipe and the press fitting 1, two circumferential recesses 10 are incorporated into the fitting body 2, which serve to accommodate corresponding sealing rings 11. A web 12 between the two adjacent recesses 10 is recessed relative to a surface of the adjacent pressing profile 13 of the fitting body 2. This design of the pressing profile 13 enables, among other things, the use of sealing rings 11 with a reduced diameter while maintaining the required sealing function. Accordingly, the wall thickness of the fitting body 2 can also be selected to be smaller for the same pipe diameter of a pipe to be pressed, so that the pressure loss coefficient when a fluid flows through the press fitting 1, also known as the so-called zeta value, is reduced.

[0052] A further feature that contributes to the particularly slim design of the press fitting 1 is a tubular banderole 14 applied to the press sleeve 3. The tubular banderole 14 serves, as explained below, in particular as a pressing marking for the connections of the press fitting 1. In this way, the provision of an additional plastic ring serving as a pressing marking in the pressing area 4 can be dispensed with.

[0053] In the described embodiment, the band 14 consists essentially of a thermoplastic material, in particular pre-stressed oriented polystyrene (OPS), which has been shrunk onto the pressing area 4 of the compression sleeve 3 by heating. The band 14 is heated until the band 14 is just barely rotatable, fully or partially in contact with the compression sleeve 3, but can no longer be removed from the compression sleeve 3 via the flange 5.

[0054] Alternatively, the band 14 can also be made of paper or another tubular, non-shrinkable material. Instead of shrinking, such a band can be produced by gluing a strip of material, such as a film or a strip of paper, into a ring. Regardless of the selected material and manufacturing process, the band 14 loosely surrounds the compression sleeve 3 in its finished state.

[0055] Such a loose connection between the band 14 and the press sleeve 3 ensures that the band 14 is largely fixed in the axial direction on the press fitting 1, but can still be moved in the tangential direction, particularly during pressing of the press sleeve 3. The loose connection thereby contributes to the destruction of the band 14, as explained in detail later. In the exemplary embodiment, the band 14 can be rotated relative to the press sleeve 3 without the use of a tool. For example, it sits so loosely on the press sleeve 3 that the band 14 is carried along by a finger tangentially brushing along its surface.

[0056] The banderole 14 not only serves as a pressing marking but also carries a number of details that are useful for identifying the press fitting 1. In the Figure 1AIn the exemplary embodiment shown, it can be seen, for example, that the banderol 14 has an indication of a diameter of a pipe to be pressed with the press fitting 1 in the form of a numerical indication 15, a manufacturer's indication 16 in the form of a mark, a machine-readable marking 17 in the form of a QR code and a color marking 18 in the form of a stripe.

[0057] The color marking 18 enables easy-to-recognize coding of the pipe diameter and / or a usage specification for different pipelines, for example pipelines for gas or water.

[0058] The machine-readable marking 17 can be used to determine further technical information about the press fitting 1 using a suitable reading device, for example a smartphone with a built-in camera or an electronic pressing tool with a built-in barcode reader. For example, it is possible to display installation instructions or a data sheet for the press fitting 1 to an installer on a smartphone or similar mobile device. Such markings 17 can also be used to implement automated reporting of the pressing of a large number of press fittings 1 on a construction site or to collect bonus points when processing correspondingly marked press fittings 1.The machine-readable marking 17 may also contain a link leading to a special application or app by means of which further information about or certificates for the press fitting 1 can be retrieved or bonus points can be collected.

[0059] Finally, banderole 14 can also indicate special events or promotions of a manufacturer or seller through appropriate imprints.

[0060] In the Figures 1A to 1C In the embodiment shown, the tubular band 14 covers the pressing area 4 to a large extent, that is to say more than half, preferably more than three-quarters, even more preferably almost completely. However, it does not completely reach the retaining ring 6. As is particularly evident in the Figure 1BAs shown, a viewing window 20 in the form of a bore is incorporated into the press sleeve 3 in an intermediate area 19 between the band 14 and the retaining ring 6. Through the viewing window 20, a fitter can see whether a pipe end has been fully inserted into the press fitting 1 before beginning the pressing process. The band 14 does not obstruct the view of the viewing window 20 or the pipe end underneath.

[0061] Figure 2 shows a further embodiment of a press fitting 21 according to the present invention. The press fitting 21 is an elbow-shaped press connector for connecting two pipes. Accordingly, the fitting body 22 is designed as an angle piece. The two connections of the press fitting 21 essentially correspond to the connections of the straight press fitting 1 according to the Figures 1A to 1C and are therefore not described again here.

[0062] Figure 3shows another press fitting 23 in the form of a connector. Three connections for pipe connections are provided on a T-shaped fitting body 24. These largely correspond to the connections of the straight press fitting 1 according to the Figures 1A to 1C . In contrast, three press sleeves 25 of the press fitting 23 are only slightly widened at their distal end, but do not have a flange, as shown in the Figures 1A to 1C and 2 is shown. Furthermore, a banderol 26 on the left and right connection of the press fitting 23 covers the entire pressing area 4. No banderol was applied to the lower connection of the press fitting 23 in order to show the press sleeve 25 underneath.

[0063] To still allow inspection of a pipe end inserted into the compression sleeve 25, a plastic film of the band 26 is transparent at the right connection. Thus, the band has a transparent viewing window 27 at its proximal end, which provides a view of a U-shaped cutout 28 of the compression sleeve 25 located underneath.

[0064] In addition, a retaining ring 29 has a window 30 in the area of ​​the U-shaped cutout 28 on a side opposite the pressing area 4. The window 30 also allows a visual inspection of a pipe end during insertion and pressing, from a different angle than the transparent viewing window 27. Furthermore, they allow a pressing check even when using a non-transparent plastic film for the banderol 26, as shown on the left connection of the press fitting 23.

[0065] The Figures 4A and 4Bshow schematically the design of the pressing profile 13 of the fitting body 2 and an associated pressing jaw 31 of a suitable pressing tool. Figure 3A shows a first section comprising the pressing jaw 31 of the pressing tool (not shown otherwise), and Figure 3B shows an enlargement of the first section in a sealing area of ​​the fitting body 2. In the Figures 4A and 4B In the state shown, a pipe end 32 has been fully inserted into a connection of the press fitting 1. However, pressing by the pressing tool has not yet taken place.

[0066] As particularly in the Figure 4AAs can be seen, the pressing jaw 31 covers the entire pressing area 4 between the distal flange 5 and the proximal retaining ring 6. This enables simple and precise positioning of the pressing jaw 31 on the pressing sleeve 3, wherein the pressing jaw 31 is guided on both sides by the flange 5 and the retaining ring 6. The pressing jaw 31 has a plurality of protruding areas 33a to 33d. In particular, a second protruding area 33b is positioned directly opposite one of the two recesses 10 with a sealing ring 11 received therein. The second protruding area 33b is located exactly in the middle of the pressing jaw 31, so that it maintains its position even when the pressing tool is rotated. The second recess 10 with the second sealing ring 11 serves as a further safety feature in case the pressing jaw 31 is placed too far forward on the press fitting 1 despite the flange 5.The high pressing forces in the protruding areas 33a to 33d of the pressing jaw 31 preferentially support the destruction of the banderol 14.

[0067] As particularly in the Figure 4B As can be seen, the web 12, which separates the two corresponding recesses 10 for receiving the sealing rings 11 from one another, is lower in cross-section than the adjacent area of ​​the pressing profile 13 of the base body 2 to the right and left. The sealing rings project beyond the upper end of the web 12 and end essentially at the level of the pressing profile 13 to the left and right. In this way it is ensured that the pipe end 32 bends evenly, in particular in an S-shape, in this area and can be reliably pressed onto the fitting body 2 to such an extent that a sealing connection is created between the pipe end 32, at least one of the sealing rings 11 and the fitting body 2.

[0068] Compared to the use of a single sealing ring with a larger cross-section, in the arrangement shown as described above, the wall thickness of the fitting body 2 can be selected to be smaller for the same pipe diameter of a pipe end 32 to be pressed, so that the pressure loss coefficient when a fluid flows through the press fitting 1 is reduced.

[0069] Figure 5Ashows a perspective view of a press fitting 1 according to the invention during a pressing process with a pressing tool 34. During pressing, the pressing jaws 31 of the pressing tool 24 are brought together, optionally hydraulically, so that they reduce their inner diameter. This creates a large contact pressure between the pressing jaws 31 and the band 14 surrounding the pressing sleeve 3. By reducing the diameter of the pressing jaws 31, a tangential force is effectively exerted on the band 14, so that part of the plastic film is transported into the closing area of ​​the pressing jaws 31. In particular, excess material, which is partly due to the loose fit of the band 14 and partly to the reduction in the diameter of the pressing sleeve 3 during pressing, is transported into the closing plane of the pressing tool 34 and forms a gusset there.The gusset is pressed or destroyed by the closing pressing jaws 31. This leads to damage and usually even to tearing of the band 14. This at least partial destruction of the band 14 also serves as a pressing mark in the described embodiment.

[0070] The condition immediately after removing the pressing tool 34 after pressing is shown in the Figure 5B . Here, it can be seen that the band 14 still largely surrounds the pressed press sleeve 3, but has a crack in the axial direction. Thus, the damaged band 14 falls off the press sleeve 3 after pressing or can at least be easily removed from the press sleeve 3 by two fingers of a fitter to indicate a successful pressing of the press fitting 1. This condition is shown in the Figure 5C Also shown in the Figure 5CIt can be seen that the diameter of the press sleeve 3 has been reduced particularly significantly, particularly in the protruding areas of the press jaw 31 of a press tool 34, in order to ensure that the connection is tight.

[0071] Unlike many conventional press fittings, the retaining ring 6 remains on the pressed fitting 1. Since it is located outside the pressing area 4, it is not destroyed during the pressing process. This has the advantage that no plastic fragments are generated on site, which could lead to a blockage of the pressing tool.

[0072] Although this is in the Figures 1A to 5Ccannot be seen, the tearing or manual removal of a partially destroyed band 14 can be made easier by providing suitable predetermined breaking points. For example, it is possible to introduce a perforation line running in an axial or helical direction into the band 14. Such a perforation line is not absolutely necessary for destroying the band 14 during pressing. However, it also helps when shrinking the band 14 onto the compression sleeve 3 by allowing the controlled escape of air inclusions underneath. Instead of perforations, corresponding recesses or incisions can also be provided in the band 14.

[0073] In the Figures 6A and 6B Different print templates for producing a banderol serving as a pressing marking are shown.

[0074] Figure 6Ashows a first print template for a flat film 35 for producing a marking for a press fitting with a pipe diameter of 16 mm. A print area 36 has the already described with reference to the Figure 1 The film 35 has the information described above, 15, 16, 17, and 18. An upper and lower edge area 37 of the film 35 is not printed in the described embodiment and is thus potentially available for a transparent viewing window. A lateral unprinted zone 38 serves to bond the film 35 to the tubular banderol 14.

[0075] As in the Figure 6AAs shown, the film 35 has four perforation lines 39, which are produced in the form of fine needle punctures in the film 35. After the film 35 has been rolled up into a tubular band, these perforation lines run in the axial direction and thus allow both the escape of air between the film 35 and the compression sleeve 3 during shrinking and pressing with the pressing tool, as well as easier destructibility of the band in the tangential direction. In particular, the provision of at least one perforation line prevents air bubbles trapped during a pressing process from reaching the closing plane of the pressing jaw 31 and bursting explosively there. This would lead to undesirable noise and possibly to flying film particles.

[0076] Figure 6B shows an alternative design of a film 40 for a pipe connector with a diameter of 32 mm.

[0077] Deviating from slide 35 according to Figure 6A No machine-readable markings are printed on the film 40. An upper edge area of ​​the film 40 is not printed and forms a transparent viewing window 27. In addition, the print template according to Figure 6B Various color patterns 41 and position markings 42 can be seen, which serve to precisely position the print on the film 40. Cutting marks 43 indicate where the film 40 must be cut to produce individual banderoles 26.

[0078] In the described embodiment, the films 35 and 40 are printed on one side using an offset printing process. Printing the films 35 and 40 with a suitable varnish reduces the static friction on the printed side of the films 35 and 40, respectively. A further reduction in static friction can be achieved by printing with a special anti-friction varnish.

[0079] The films 35 and 40 are then rolled together by connecting the lateral edge regions 37 into tubular bands 14 and 26, respectively, such that the printed surface is located on the inside of the band 14 and 26, respectively. This ensures that the print on the films 35 and 40 is protected from damage during transport of the press fittings 1, 21 and 23, respectively.

[0080] At the same time, the static friction between the compression sleeve 3 or 25 and the banderol above it is reduced compared to the static friction between the outer side of the banderol 14 or 26 and a pressing jaw 31 of a pressing tool 34. This results in the banderol 14 or 26 being carried along by the pressing jaws 31 in a tangential direction when the compression sleeve 3 or 25 is pressed and slides on the surface of the compression sleeve 3 or 25, thus ensuring reliable destruction of the banderol 14 or 26.

[0081] The radial twistability of the banderole 14 or 26 required for this purpose can alternatively or additionally be ensured by a suitable choice of temperature or duration of a shrink-fitting process. Figure 7A schematic representation of a shrinkage curve of a thermoplastic material. Depending on a prevailing temperature T between 50 and 95 °C, a predetermined shrinkage duration, for example, 10 seconds, results in a deterministically predictable shrinkage ratio R. Depending on the inner diameter of the tubular band 14 or 26 before a shrinking process and the outer diameter of the compression sleeve 3 or 25, the temperature is selected such that the band 14 or 26 can still be rotated radially after the shrinking process.

[0082] Figure 8 shows schematically the process steps for producing a press fitting according to an embodiment of the invention, in particular the press fitting 1 according to the Figures 1A to 1C .

[0083] In a step S1, a plastic film is first printed with a suitable printing template. For example, an initially flat OPS plastic film can be printed with one of the templates according to the Figures 6A or 6B printed. Offset or laser printing processes are suitable for this purpose.

[0084] Subsequently, the edge regions 37 of the printed film 35 and 40 are rolled together to form a film tube. The two edge regions are then joined together, for example, by welding or gluing, in a step S2.

[0085] In a preferred embodiment, several similar markings are printed one above the other on an elongated film web. In this way, a plurality of bands 14 or 26 can be produced simultaneously. These are separated from one another in a subsequent, optional step S3 by cutting at predetermined separation planes.

[0086] The individual bands 14 and 26 produced in this way are applied to a press sleeve 3 and 25, respectively, in a step S4. For example, the band 14 can be applied to the press sleeve 3 via the widened area 7 on the back according to the Figures 1A to 1C The flange 5 points downwards and serves as a stop and positioning aid for the band 14. In an optional step, a lubricant, such as oil, wax, or a water or other fluid film, can be introduced between the press sleeve 3 or 25 and the band 14 or 26.

[0087] In a step S5, the band 14 or 26 is heated for a predetermined time at a predetermined temperature so that the thermoplastic film contracts. For example, the time can be selected or determined by the duration of a passage through a process furnace. The temperature and / or duration of the heating step are selected such that the band 14 or 26 rests loosely on the press sleeve 3 or 25 at the end of the heating. Preferably, the band 14 or 26 is already held securely in the axial direction on the press sleeve 3 or 25 in this state, for example between the widened region 7 and the flange 5. The press sleeve 3 or 25 heats up only slightly while passing through the process furnace.Due to the relatively large mass and thermal capacity of the compression sleeve 3 or 25, the shrinking process ends at the latest when the band 14 or 26 comes into contact with the cool compression sleeve 3 or 25. Additional cooling of the band 14 or 26 to complete the shrinking process is therefore not necessary.

[0088] In an optional modification, the compression sleeve 3 or 25 with the band 14 or 26 is cooled abruptly, for example, using a water bath. This procedure prevents subsequent, unwanted shrinkage of the band material. Any remaining water between the compression sleeve 3 or 25 and the band 14 or 26 also serves as a lubricant.

[0089] In a subsequent step S6, a retaining ring 6 or 29 is attached to the compression sleeve 3 or 25. This can be done, for example, by locking the retaining ring 6 or 29 to the compression sleeve 3 or 25, or by injection-molding the retaining ring 6 or 29 directly onto the compression sleeve 3 or 25. At the latest, this secures the banderol 14 or 6 axially in both directions.

[0090] In a step S7, the compression sleeve 3 or 25 is attached to the fitting body 2, 22 or 24. In the exemplary embodiment, this is achieved by placing the entire sleeve assembly onto the fitting body 2, 22 or 24 and locking it there. Of course, a reversal of these steps is also possible, i.e., the retaining ring 6 or 29 is molded or locked directly onto the fitting body 2, 22 or 24 and the retaining ring 6 or 29 is locked to the compression sleeve 3 or 25.

[0091] In an alternative embodiment of the method, the band 14 or 26 is applied to the press sleeve 3 or 25 only after the assembly of the remaining press fitting 1, 21 or 23. The inner diameter of the not yet shrunk band 14 or 26 is selected to be large enough that it can be pushed onto the press sleeve 3 or 25 via a protruding element at the distal end of the press sleeve 3 or 25, in particular the flange 5 of the press sleeve 3. During the heating step, the band 14 or 26 then shrinks to such an extent that it is held in the pressing area 4 by the protruding element. In this case, steps S6 and S7 are carried out before steps S4 and S5.

[0092] In a further alternative embodiment of the method, the band 14 or 26 is not shrunk onto the compression sleeve 3 or 25. Instead, the inner diameter of the band 14 or 26 before the band 14 or 26 is applied to the compression sleeve 3 or 25 essentially corresponds to the outer diameter of the compression sleeve 3 or 25. In this case, step S5 is omitted without replacement.

[0093] Instead of the above-mentioned plastic film, another non-shrinkable carrier or banding material, for example a sheet of paper, can then be used to produce the bands 14 and 26, respectively, in steps S1 to S3.

[0094] For example, an already closed, tubular band 14 or 26 can be pushed onto the compression sleeve 3 or 25 from the proximal end before the compression sleeve 3 or 25 is fastened to the fitting body 2 in step S7. Alternatively, a strip of material, for example a strip of paper, can be guided around the compression sleeve 3 or 25 and only then glued to form a tubular band 14 or 26 in an overlapping manner.

[0095] In all the cases described, the banderole 14 or 26 is fixed in the finished state of the press fitting 1, 21 or 23 in the axial direction by protruding parts of the press fitting 1, 21 or 23, in particular the flange 5 or another protruding area at the distal end and by the retaining ring 6 or another protruding area at the proximal end. List of reference symbols

[0096] 1 Press fitting 2 Fitting body 3 Press sleeve 4 Press area 5 Flange 6 Retaining ring 7 Expanded area 8 Locking lug (of retaining ring 6) 9 Locking lug (of fitting body 2) 10 Recess 11 Sealing ring 12 Web 13 Press profile 14 Band 15 Number 16 Manufacturer's information 17 Machine-readable marking 18 Color marking 19 Intermediate area 20 Viewing window 21 Press fitting 22 Fitting body 23 Press fitting 24 Fitting body 25 Press sleeve 26 Band 27 Transparent viewing window 28 U-shaped recess 29 Retaining ring 30 Window 31 Press jaw 32 Pipe end 33 Protruding area 34 Press tool 35 Film 36 Printing area 37 Edge area 38 Unprinted area 39Perforation line 40Foil 41Color sample 42Position mark 43Cutting mark S1 to S9Procedure steps

Claims

1. Press fitting (1, 21, 23) for a pipe connection, comprising: - a fitting body (2, 22, 24) for connecting the press fitting (1, 21, 23) to a pipe; - a press sleeve (3, 25) attached to the fitting body (2, 22, 24), the press sleeve having a substantially cylindrical pressing region (4) and at least one protruding element that defines the substantially cylindrical pressing region (4) in the axial direction; - a tubular banderole (14, 26) which surrounds the substantially cylindrical pressing region (4) of the press sleeve (3, 25), the tubular banderole (14, 26) being held in the cylindrical pressing region (4) by the at least one protruding element, being arranged to be rotatable relative to a surface of the press sleeve (3, 25) and configured such that it is carried along by the pressing jaws (31) of a pressing tool (34) when the press sleeve (3, 25) is pressed and at least partially destroyed in the process.

2. Press fitting (1, 21, 23) according to Claim 1, wherein the outside of the tubular banderole (14, 26) has a greater surface roughness than the inside of the tubular banderole (14, 26).

3. Press fitting (1, 21, 23) according to Claim 2, - wherein the inside or the outside of the tubular banderole (14, 26) is printed and the printed side has a different surface roughness to the unprinted side; and / or - wherein the inside of the tubular banderole (14, 26) is printed with a lubricating coating.

4. Press fitting (1, 21, 23) according to any one of Claims 1 to 3, wherein the tubular banderole (14, 26) is made of a plastic film.

5. Press fitting (1, 21, 23) according to Claim 4, - wherein the plastic film of the tubular banderole (14, 26) comprises a thermoplastic material and the tubular banderole (14, 26) is shrink-fitted onto the substantially cylindrical pressing region (4); and / or - wherein the plastic film of the tubular banderole (14, 26) has a thickness of between 10 and 200 µm, preferably between 35 and 90 µm, particularly of 40, 45, or 50 µm; and / or - wherein the plastic film of the tubular banderole (14, 26) comprises at least one of the following materials: oriented polystyrene (OPS), polyethylene terephthalate (PET), polylactide (PLA) and polyvinyl chloride (PVC).

6. Press fitting (1, 21, 23) according to any one of Claims 1 to 3, wherein the tubular banderole (14, 26) is made of a paper strip.

7. Press fitting (1, 21, 23) according to any one of Claims 1 to 6, - wherein the tubular banderole (14, 26) does not have a predetermined breaking point; or - wherein the tubular banderole (14, 26) has at least one perforation line (39), a slit and / or a cut-out.

8. Press fitting (23) according to any one of Claims 1 to 7, wherein the tubular banderole (26) substantially covers the entire pressing region (4).

9. Press fitting (23) according to any one of Claims 1 to 7, - wherein the press sleeve (25) comprises at least a first viewing window and the at least one tubular banderole (26) substantially covers the entire pressing region (4) and a second viewing window (27) corresponding to the first viewing window, which are arranged in such a manner that it is possible to determine whether a pipe end (32) has been fully inserted into the press fitting (23) without removing the tubular banderole (26); or - wherein the press sleeve (3) comprises at least one viewing window (20) and the tubular banderole (14) does not cover the pressing region (4) of the press sleeve (3), at least in the area in which the viewing window (20) is located, so that it is possible to see whether a pipe end (32) has been fully inserted into the press fitting (1, 21) without removing the tubular banderole (14).

10. Press fitting (1, 21, 23) according to any one of Claims 1 to 9, wherein the tubular banderole (14, 26) bears at least one technical specification relating to the type, installation or use of the press fitting (1, 21, 23); in particular, wherein the at least one technical specification comprises at least one usage indication and / or diameter indication in the form of a colour marking(18); and / or wherein the at least one technical specification comprises at least one machine-readable marking (17), in particular a barcode or a two-dimensional data matrix, wherein the machine-readable marking (17) contains a reference to further technical information about the press fitting (1, 21, 23) stored in a data network, in particular an installation instruction or data sheet.

11. Press fitting (1, 21, 23) according to any one of Claims 1 to 10, further comprising a retaining ring (6, 29), wherein the retaining ring (6, 29) is arranged at an end of the press sleeve (3, 25) opposite the protruding element and delimits the pressing region (4) in this axial direction, wherein the protruding element is arranged at a distal open end of the press sleeve (3, 25) for receiving a pipe and the retaining ring (6, 29) is arranged at a proximal end of the press sleeve (3, 25), and the press sleeve (3, 25) is held on the fitting body (2, 22, 24) of the press fitting (1, 21, 23) by means of the retaining ring (6, 29).

12. Method for producing a press fitting (1, 21, 23) according to any one of Claims 1 to 11, comprising: - applying a tubular banderole (14, 26) to a substantially cylindrical pressing region (4) of a press sleeve (3, 25) with at least one protruding element, wherein the tubular banderole (14, 26) is held in the substantially cylindrical pressing region (4) by the at least one protruding element and is arranged to be rotatable relative to a surface of the press sleeve (3, 25), so that it is carried along by the pressing jaws (31) of a pressing tool (34) when the press sleeve (3, 25) is pressed and at least partially destroyed in the process; and - securing the press sleeve (3, 25) to a fitting body (2, 22, 24).

13. Method according to Claim 12, - wherein the step of applying the tubular banderole (14, 26) is carried out before the step of fixing the press sleeve (3, 25) to the fitting body (2, 22, 24); or - wherein the step of securing the press sleeve (3, 25) to the fitting body (2, 22, 24) is carried out before the step of applying the tubular banderole (14, 26).

14. Method according to any one of Claims 12 to 13, wherein the tubular banderole (14, 26) is made of a plastic film comprising a thermoplastic material and the method further involves heating the tubular banderole (14, 26) so that the plastic film shrinks onto the substantially cylindrical pressing region (4), wherein a temperature and / or duration of heating is / are selected in such a manner that, after cooling, the tubular banderole (14, 26) is arranged to be rotatable relative to the surface of the press sleeve (3, 25).

15. Method according to Claim 14, wherein the diameter of the tubular banderole (14, 26) is selected in such a manner that the tubular banderole (14, 26) can be applied to the substantially cylindrical pressing region (4) over the at least one protruding element before heating and that after heating, the tubular banderole (14, 26) is held in the substantially cylindrical pressing region (4) by the at least one protruding element.

16. Method according to any one of Claims 12 to 14, wherein the step of securing the press sleeve (3, 25) to the fitting body comprises: - applying a retaining ring (6, 29) to the press sleeve (3, 25); and - connecting the fitting body (2, 22, 24) to the retaining ring (6, 29).

17. Method according to Claim 16, further comprising: - printing the carrier material, in particular using an offset or laser printing process; and / or - perforating a material of the tubular banderole, in particular a plastic film.