ASSEMBLY GROUP FOR A PRESS FITTING, PRESS FITTING AND ASSEMBLY PROCEDURES FOR A PRESS FITTING

Description

[0001] The invention relates to an assembly for a press fitting, comprising a press sleeve and a stop ring. The invention further relates to a press fitting with such an assembly and an assembly method for such a press fitting.

[0002] Press fittings for pipe connections are known from the state of the art. For example, DE 10 2018 109 555 B3 discloses a press fitting 101 for a pipe connection, which is Figure 12 is shown.

[0003] The press fitting 101 according to Figure 12comprises a fitting body 102 for connecting the press fitting 101 to a pipe, two press sleeves 103 fixed to the fitting body 102, each having a substantially cylindrical pressing area 104 and at least one protruding element in the form of a flange 105, which delimits the substantially cylindrical pressing area 104 in the axial direction, and a tubular banderole 114 made of a plastic film. As in the Figure 12 As can be seen, each of the compression sleeves 103 is secured to the fitting body 102 by means of a retaining ring 106. For this purpose, the compression sleeve 103 has a slightly widened area 107 at its proximal end, which is locked to the retaining ring 106. The retaining ring 106 is further locked to the fitting body 102 via two opposing locking lugs 108 and 109.

[0004] Furthermore, EP 1 790 896 A1 discloses a press fitting 210 for a pipe, in particular a plastic pipe or a pipe made of a plastic-metal composite material, which is Figure 13 is shown.

[0005] The press fitting 210 of the Figure 13 is provided with a fitting body 212, which has a support body 216, onto which a pipe 220 to be connected can be pushed, a press sleeve 230, which has a pressing area 266, in which a pressing tool acts upon pressing the press sleeve 230, and a pressing indicator ring 252, which is held on an outer bead 244 of the press sleeve 230. The press fitting 210 of the Figure 13 differs from the Pressfitting 101 of the Figure 12 that an inner projection 248 of the press sleeve 230 dips directly into an outer circumferential recess 228 of the fitting body 212.

[0006] EP 1 933 073 A1 discloses a press fitting for a pipe which is provided with a fitting body and has a support body onto which a pipe to be connected can be pushed. The press fitting also has a press sleeve which has a holding end at which the press sleeve is held on the fitting body. At its holding end, the press sleeve has edge recesses which are open towards the front side of the press sleeve. A plastic ring lies on the outside of the press sleeve and is secured to the press sleeve against movement in the axial direction of the press sleeve, wherein the plastic ring has at least one axially projecting projection which extends into the pressing area of ​​the press 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 press sleeve.

[0007] The present invention is based on the object of describing an improved, preferably particularly easy-to-manufacture press fitting. In particular, a press fitting is to be described in which damage to individual components, such as the fitting body, can be reduced or avoided during production, and / or which enables the creation of a permanent connection between a press sleeve and a stop ring that is resistant to impacts, for example, from a lateral direction, even during production and before the press fitting is pressed.

[0008] The invention is defined in the appended claims.

[0009] According to a first aspect of the disclosure, an assembly for a press fitting is described. The assembly comprises a substantially cylindrical press sleeve with a pressing region and a stop ring secured to a first axial end of the press sleeve, which delimits the pressing region in an axial direction of the press sleeve. The stop ring has a first inner contour on a side opposite the pressing region for applying the assembly to a fitting body of the press fitting, as well as a first circular segment and an adjacent second circular segment, which extends over a smaller part of the first inner contour than the first circular segment.Furthermore, the stop ring has a cross-section that is constant in the area of ​​the first circular segment and an element that is arranged in the area of ​​the second circular segment and that projects inwards beyond the constant cross-section of the first circular segment, so that when the assembly group is applied to the fitting body, it causes a relative tilting of an axis of symmetry of the press sleeve with respect to a central axis of the fitting body.

[0010] Such an assembly is automatically tilted when applied to the fitting body of a press fitting, facilitating the assembly's application. At the same time, the forces generated during assembly are reduced, largely preventing damage to parts of the press fitting, especially the fitting body, during assembly.

[0011] According to the claim, the first inner contour has a chamfer in the area of ​​the first circular segment, the clear inner diameter of which decreases in the axial direction of the assembly from the side opposite the pressing area. An internal chamfer on the stop ring simplifies centering and mounting the assembly on the fitting body.

[0012] According to the claim, the element arranged in the region of the second circular segment has an insertion bevel. An inclination angle of the insertion bevel is greater than an inclination angle of the chamfer, in each case relative to the axis of symmetry of the assembly, and / or a surface of the filling bevel is offset radially inward relative to a corresponding surface of the chamfer. Such an insertion bevel supports the centering and application of the assembly and simultaneously causes its tilting.

[0013] According to an alternative, unclaimed embodiment, the element arranged in the region of the second circular segment is designed as a tab protruding radially from the constant cross-section of the first circular segment. Such a configuration is particularly easy to manufacture and ensures secure tilting of the assembly.

[0014] According to a second aspect of the disclosure, a press fitting is described that comprises a fitting body and an assembly assembly according to the first aspect, which is secured to the fitting body. Such a press fitting can be assembled particularly easily and with relatively low forces.

[0015] In at least one embodiment, the fitting body has a circumferential groove, and the compression sleeve has a first projection at the first axial end that points radially inward and engages the groove, so that the compression sleeve is directly secured to the fitting body. Such direct fastening of a compression sleeve directly to a fitting body prevents accidental detachment of the compression sleeve from the fitting body while simultaneously limiting the assembly force required to apply it due to tilting.

[0016] According to a third aspect of the disclosure, an assembly method for the press fitting according to the second aspect is described. The assembly method comprises the following steps: Attaching the stop ring to a first axial end of the press sleeve, relative tilting of the symmetry axis of the press sleeve relative to a central axis of the fitting body by means of the element arranged in the region of the second circular segment of the stop ring, in the tilted state, applying the press sleeve with the stop ring attached thereto with the first axial end first onto a fitting body, and locking the press sleeve and / or the stop ring with a groove of the fitting body, wherein the axis of symmetry of the press sleeve after locking substantially coincides with the central axis of the fitting body.

[0017] By means of the above-mentioned steps, the force required for locking a press sleeve and / or a stop ring with a fitting body can be reduced, so that in particular damage in the area of ​​a groove of the fitting body used for locking can be avoided.

[0018] According to at least one embodiment, the element arranged in the region of the second circular segment abuts a raised portion of the fitting body located in front of the groove in the application direction, particularly in the form of a rib, during the step of applying the press sleeve. This leads to the relative tilting of the axis of symmetry of the press sleeve relative to the central axis of the fitting body. This allows the press fitting to be assembled without further adaptation of the machines and / or tools used for its assembly. Further advantageous embodiments are disclosed in the appended claims and the following detailed description of exemplary embodiments.

[0019] The invention will be explained in detail below using various exemplary embodiments with reference to the attached figures. Like reference numerals designate identical or similar components in different exemplary embodiments. Figure 1 shows an exploded view of a press fitting with a stop ring. Figures 2 to 4 show different views of a stop ring according to Figure 1 Figure 5 shows the press fitting according to Figure 1 in the assembled state. Figure 6 shows a cross section through the press fitting according to Figure 5 Figure 7 shows an alternative design of a stop ring. Figures 8 and 9 show different views of another stop ring. Figure 10 shows the assembly of an assembly group on a fitting body. Figure 11 schematically shows a method for assembling a press fitting. Figure 12 shows a first press fitting according to the prior art. Figure 13 shows a second press fitting according to the prior art.

[0020] Figure 1 shows an exploded view of a press fitting 1. The press fitting 1 has a fitting body 2, a stop ring 3 and a press sleeve 4.

[0021] In the illustrated embodiment, the fitting body 2 is a straight, essentially cylindrical coupling for connecting two pipes of the same diameter. Of course, other fitting bodies, such as angled connectors, T-pieces, or couplings for connecting pipes of different diameters, are also possible.

[0022] The fitting body 2 can be made of a plastic tool, such as a polymer material, or of a metal material. The surface of the fitting body 2 has several elevations and grooves, which ensure a secure and tight pressing of a Figure 1 not shown pipe, for example a plastic, metal or composite pipe, with the fitting body 2. For this purpose, further Figure 1 For reasons of clarity, sealing elements not shown may be applied to the fitting body 2.

[0023] The fitting body 2 comprises a central region 5 and two opposing connection regions 6a and 6b. In the central region 5, adjacent to the respective connection regions 6a and 6b, grooves 7a and 7b are provided, respectively, which serve to engage with first projections in the form of lips 8 projecting inward from the compression sleeve 4.

[0024] The compression sleeve 4 is typically made of a metal material, in particular stainless steel. In order to reduce the force required to lock the compression sleeve 4 to the fitting body 2, a first axial end 9 of the compression sleeve 4 is provided with a plurality of slots 10. The slots 10 facilitate widening of the first axial end 9 when the compression sleeve 4 is pushed onto the fitting body 2. The first axial end 9 of the compression sleeve 4 points towards the central region 7 of the fitting body 2 and can thus also be referred to as the proximal end. Before the compression sleeve 4 is applied to the fitting body 2, the stop ring 3 is first mounted on it.

[0025] The stop ring 3 is typically made from a plastic tool, in particular a polymer material, and delimits a pressing area 11 of the press sleeve 4 at the first axial end 9 of the press sleeve 4. At the opposite, distal or second axial end 12 of the press sleeve 4, the pressing area 11 is delimited in the illustrated embodiment by a second projection in the form of a flange 13 of the press sleeve 4 itself. During pressing of the press fitting 1, pressing jaws of a pressing tool (not shown in the figures) act on the pressing area 11 of the press sleeve 4 and thus establish a positive connection between the fitting body 3, a pipe end inserted into the press fitting, and the press sleeve 4.

[0026] In order to securely fasten the stop ring 3 to the press sleeve 4 before mounting the press sleeve 4 on the fitting body 2, the stop ring 3 has an inner contour 14 on the sleeve side, which serves to produce a clamp connection.

[0027] As in the Figures 2 to 4 As can be seen, the inner contour 14 in the illustrated embodiment has a total of eight protruding, first regions 15. Between them are eight receding, second regions 16. The stop ring 3 can deform slightly when pushed onto the first axial end 9 of the compression sleeve 4. In this case, the first regions 15, in particular, create a clamping fit.

[0028] For this purpose, a first inner diameter d 1 of a remaining clear area between the first areas 15 is dimensioned such that it is smaller than a Figure 6The illustrated outer diameter d 3 of the press sleeve 4 plus a possible negative manufacturing tolerance. For example, a press sleeve for a pipe diameter of 25 mm can have a tolerance range of approximately 0.25 mm, i.e., approximately 1% of the nominal diameter. In this case, the first inner diameter d 1 between the end faces of the first regions 15 is dimensioned such that, even with a minimum permissible outer diameter of the press sleeve 4, an overlap of 0.1 mm remains to provide a clamping force. Conversely, with a maximum permissible outer diameter of the press sleeve 4, an overlap of 0.35 mm exists.

[0029] In contrast, a second inner diameter d 2 between two opposite, most recessed parts of the second regions 16 is dimensioned so large that in any case a clear distance remains between a circumferential surface of the compression sleeve 4 and a corresponding second region 16 of the inner contour 14 of the stop ring 3. For example, a minimum clearance of 0.1 mm remains in the case of a maximum outer diameter of the compression sleeve 4 within the tolerance range and a maximum distance of 0.35 mm in the case of a minimum outer diameter of the compression sleeve 4. In the embodiment according to the Figures 1 to 3The first regions 15 are connected to the second regions 16 by arcuate transition regions 30, in which the inner diameter of the stop ring 3 steadily increases. The advantage of this design is that the arcuate transition regions 30 are particularly mechanically stable. Furthermore, the protruding first regions 15 are designed so wide that they do not fully penetrate the slots 10 of the compression sleeve 4 during assembly of the stop ring 3.

[0030] In cross section according to Figure 4 It can be seen that a first side 17 of the stop ring 3, which faces the pressing area 11 in the assembled state, has a first chamfer 18. The first chamfer 18 enables centering and easy insertion of the connecting ring 3 onto the first axial end 9 of the pressing sleeve 3.

[0031] Furthermore, it can be seen that an opposite second side 19 of the stop ring 3, which in the assembled state faces the central region 6 of the fitting body 2, has a fitting-side inner contour 20 with a second chamfer 21. The second chamfer 21 serves, among other things, to center an assembly group comprising the stop ring 3 and the press sleeve 4 during their assembly on the fitting body 2. An arcuate outer contour 22 of the stop ring 3 continuously connects the outer diameter of the first side 17 with the outer diameter of the second side 19, so that there are no steps in the cross-section. The sleeve-side inner contour 14 and the fitting-side inner contour 20 are separated from one another by an inwardly projecting third projection, which simultaneously forms an open bottom surface 23 of the sleeve-side inner contour 14 and limits a maximum insertion depth of the press sleeve 4.

[0032] When assembled according to the Figures 5 and 6the third projection or the open bottom surface 23 of the stop ring 3, as shown in the cross section of the Figure 6 shown, engage completely or partially in the groove 7 of the fitting body 2. With appropriate dimensioning, it can also rest on a surface of the fitting body 2 outside the groove 7. In the exemplary embodiment, it limits the insertion depth of the assembly when applying the press sleeve 4 to the connection area 6a, in that the second side 19 of the stop ring 3 abuts an end face 35 of the central area 5.

[0033] Figure 7 shows an alternative design of a sleeve-side inner contour 14 of a stop ring 3. Deviating from the stop ring 3 according to the Figures 1 to 4 includes the inner contour 14 according to Figure 7a substantially cylindrical inner surface 24 and webs 25 arranged thereon. In the exemplary embodiment, a total of eight such webs 25 are present, which form the first regions 15 of the stop ring 1. The intermediate sections of the cylindrical inner surface 24 form the second regions 16. Regarding their dimensions, reference is made to the above.

[0034] In the following, the Figures 8 to 10A further aspect of the fitting-side inner contour 20 according to a further embodiment of a connecting ring is described. In this exemplary embodiment, the fitting-side inner contour 20 has a protruding element 26, which is arranged in a relatively small circular segment 27 of the stop ring 3. In the remaining part, corresponding to a larger circular segment 31, the stop ring 3 has a constant cross-section. In this context, "protruding" means that a surface of the element 26 facing the center of the stop ring 3 protrudes beyond a surrounding surface of the fitting-side inner contour 20 or the constant cross-section in the circular segment 31. For example, the element 26, as shown in the Figure 10shown, be designed as a tab 33 projecting radially inward from the inner circumference of the stop ring 3, i.e. perpendicular to its axis of symmetry. In contrast, according to the invention, the element 26 is designed as shown in the Figures 8 and 9 shown as an insertion bevel 32, which can also form part of the second bevel 21. In this case, an obliquely inwardly inclined surface of the insertion bevel 32 in the region of the smaller circular segment 27 in which the element 26 is formed is either displaced parallel inwardly relative to a surface of the bevel 21 or has a greater inclination in the insertion direction than the second bevel 21 of the fitting-side inner contour 20.

[0035] The element 26 serves in particular to lead to a relative tilting of the axes of the press sleeve 4 with the connection ring 3 placed thereon onto a connection area 6 of the fitting body 2.

[0036] In the Figure 10In the illustrated embodiment, an assembly 28, comprising the compression sleeve 4 and the connecting ring 3, stands upright and with its first axial end 9 pointing upwards on a flat surface, such as a holding device of a machine tool. A fitting body 2 with a downward-facing connection region 6 is then inserted substantially vertically from above into the opening of the assembly 28. The axial directions of the assembly 28 and the fitting body 2 initially coincide.

[0037] As soon as the second side 19 of the connecting ring 3 meets a circumferential rib 29 located in front of the groove 7, the element 26 causes Figure 10in the form of a tab 33, an asymmetrical force distribution, which, as shown, leads to a slight relative tilting of the central axis AF of the connection area 6 relative to the axis of symmetry AS of the assembly group 28 or the press sleeve 4. For example, the fitting body 2 can be tilted by approximately 2 to 5°.

[0038] As a result, the segments 34 of the compression sleeve 4 formed between the slots 10 of the compression sleeve 4, with the lips 8 formed thereon, expand slightly one after the other during locking. This significantly reduces the forces required to connect the assembly group 28 to the fitting body 2 and thus facilitates the insertion of the connection area 6 into the assembly group 28.

[0039] Under test conditions, the assembly forces for a press fitting 1 for a nominal pipe diameter of 25 mm could be reduced to a press-in force of 242 N compared to a press-in force of approximately 2100 N with coaxial pressing by offsetting or tilting the connection area 6 into the assembly group 28, which considerably facilitates the assembly of the press fitting 1. For a nominal pipe diameter of 32 mm, the press-in force was reduced from 1500 N to 314 N. This reduction in the forces occurring during assembly has the additional advantage that damage to the fitting body 2 can be avoided, particularly when plastic materials are used for the fitting body 2.

[0040] As soon as the assembly process is completed, i.e., as soon as the second side 19 of the stop ring 3 abuts against a front surface 35 formed by the central region 5, the compression sleeve 4 and the fitting body 2 are aligned coaxially again. Thus, the offset or tilted application of the assembly 28 does not adversely affect its alignment or the secure attachment of the compression sleeve 4 to the fitting body 2.

[0041] Figure 11 shows schematically the steps of a method for assembling a press fitting 1.

[0042] First, in step S1, a compression sleeve 4 with a predetermined nominal diameter is provided. This diameter can vary within a predetermined tolerance range by a certain negative and / or positive tolerance value. Preferably, the compression sleeve 4 has one or more protrusions, such as, in particular, lips 8, for direct engagement with a fitting body 2.

[0043] In a subsequent step S2, a stop ring 3 is placed onto the press sleeve 4 at a first axial end 9. Preferably, this stop ring is fastened to the press sleeve 4, for example by providing raised first regions 15 and recessed second regions 16, which result in the stop ring 3 being clamped to the press sleeve 4. Alternatively, other connections, in particular form-fitting connections, are also possible. In a further step S3, the assembly group 28 of the press sleeve 4 thus produced, with the stop ring 3 fastened thereto, is applied to a connection region 6 of a fitting body 2. This can be done, for example, using an industrial placement machine.

[0044] In a step S4, the longitudinal axes of the fitting body 2 and the assembly group 28 are tilted relative to each other. This can be done, for example, by appropriately controlling a placement machine or a press die or according to the invention, as previously described with reference to the Figures 8 to 10 described, by providing a corresponding fitting-side inner contour 20 with a protruding element 26. Subsequently, in a step S5, the assembly group 28 is further pushed or pressed onto the fitting body 2, and the press sleeve 4 is locked to the fitting body 2, for example by lips 8 engaging a corresponding groove 7 of the fitting body 2.

[0045] In the described embodiments, the stop ring 3 remains intact during the actual pressing of the press sleeve 4 with a pipe end, since the pressing tool does not exert any force on the stop ring 3 in a radial pressing direction. If an indication of the pressing is desired, the described press fitting 1 can be provided, for example, with a tubular banderole as a pressing mark. The application and advantages of such a banderole 114, as shown, for example, in the Figure 12 The features shown have already been described in detail in DE 2018 109 555 B3. To avoid repetition, reference is made to the relevant disclosure and incorporated into the present description by reference.

[0046] The previously described sleeve-side inner contour 14 on the side of the stop ring 3 facing the pressing area 11 and the fitting-side inner contour 20 on the side of the stop ring 3 facing the fitting body 2 can be combined with each other as described above. However, each of the inner contours 14 and 20 also produces the described effects and advantages on its own and can therefore also be implemented individually. List of reference symbols

[0047] 1 Press fitting 2 Fitting body 3 Connection ring 4 Press sleeve 5 Central area 6, 6a, 6b Connection area 7, 7a, 7b Groove 8 Lip (first projection) 9 First axial end 10 Slot 11 Press area 12 Second axial end 13 Flange (second projection) 14 (Sleeve-side) inner contour 15 First area 16 Second area 17 First side 18 First chamfer 19 Second side 20 (Fitting-side) inner contour 21 Second chamfer 22 Outer contour 23 Open bottom surface (third projection) 24 Inner cylinder surface 25 Web 26 Element 27 (Small) circular segment 28 Assembly group 29 Rib 30 Transition area 31 (Larger) circular segment 32 Lead-in chamfer 33 Tab 34 Segment (of the press sleeve) 35Front face

Claims

1. Assembly group (28) for a press fitting (1), having: - a substantially cylindrical ferrule (4) with a pressing region (11); and - a stop ring (3) which is secured to a first axial end (9) of the ferrule (4) and delimits the pressing region (11) in an axial direction of the ferrule (4), wherein the stop ring (3) has the following: - a first internal contour (20) on a side (19) opposite the pressing region (11), for attaching the assembly group (28) to a fitting body (2) of the press fitting (1); - a first circular segment (31) and a second circular segment (27), adjacent thereto, that extends over a smaller part of the first internal contour (20) than the first circular segment (31); - a cross section, which is constant in the region of the first circular segment (31), with a bevel (21) having a clear inside diameter that decreases from the side (19) opposite the pressing region (11) in the axial direction of the assembly group (28); and - an element (26) which is arranged in the region of the second circular segment (27) and projects inwards beyond the constant cross section of the first circular segment (31), characterized in that - the element (26) arranged in the region of the second circular segment (27) has an insertion chamfer (32), and - an inclination angle of the insertion chamfer (32) is greater than an inclination angle of the bevel (21), in each case with respect to the axis of symmetry (AS) of the assembly group (28), and / or a surface of the insertion chamfer (32) is arranged so as to be offset inwards in a radial direction with respect to a corresponding surface of the bevel (21), such that when the assembly group (28) is attached to the fitting body (2), the element (26) causes an axis of symmetry (AS) of the ferrule (4) to be tilted relative to a central axis (AF) of the fitting body (2) .

2. Assembly group (28) according to Claim 1, wherein the stop ring (3) has, on a side facing the pressing region (11), a second internal contour (14) with first regions (15) that protrude and second regions (16) that are set back compared with the first regions (15), for securing the stop ring (3) to the ferrule (4).

3. Press fitting (1) having a fitting body (2) and an assembly group (28) secured to the fitting body (2), according to Claim 1 or 2.

4. Press fitting (1) according to Claim 3, wherein - the fitting body (2) has an encircling groove (7); and - the ferrule (4) has, at the first axial end (9), a first protrusion that faces inwards in a radial direction and engages in the groove (7) such that the ferrule (4) is secured directly to the fitting body (2) .

5. Press fitting (1) according to Claim 4, wherein the first protrusion that faces inwards in a radial direction is designed in the form of a lip (8).

6. Press fitting (1) according to Claim 4 or 5, wherein the fitting body (2) has an elevation that is located ahead of the groove (7) in the attachment direction and is designed such that when the assembly group (28) is attached to the fitting body (2), the element (26) butts against the elevation of the fitting body (2) and thus results in the axis of symmetry (AS) of the ferrule (4) being tilted relative to the central axis (AF) of the fitting body (2) .

7. Press fitting (1) according to Claim 6, wherein the elevation located ahead of the groove (7) in the attachment direction is designed in the form of a rib (29) .

8. Press fitting (1) according to any of Claims 4 to 7, wherein the stop ring (3) has a second protrusion that faces inwards in a radial direction and engages in the groove (7) in the fitting body (2).

9. Press fitting (1) according to Claim 8, wherein the second protrusion that faces inwards in a radial direction is designed in the form of an open bottom area (23).

10. Assembly method (28) for a press fitting (1) according to any of Claims 3 to 9, having the steps of: - fastening the stop ring (3) to a first axial end (9) of the ferrule (4); - tilting the axis of symmetry (AS) of the ferrule (4) relative to a central axis (AF) of the fitting body (2) by means of the element (26) arranged in the region of the second circular segment (27) of the stop ring (3) ; - in the tilted state, attaching the ferrule (4), with the stop ring (3) fastened thereto, onto the fitting body (2), with the first axial end (9) first; and - latching the ferrule (4) and / or the stop ring (3) together with a groove (7) in the fitting body (2), wherein the axis of symmetry (AS) of the ferrule (4) substantially matches the central axis (AF) of the fitting body (2) after latching.

11. Assembly method (28) according to Claim 10, wherein the element (26) arranged in the region of the second circular segment (27) butts, in the step of attaching the ferrule (4), against an elevation, located ahead of the groove (7) in the attachment direction, of the fitting body (2), and results in the axis of symmetry (AS) of the ferrule (4) being tilted relative to the central axis (AF) of the fitting body (2) .

12. Assembly method (28) according to Claim 10 or 11, also comprising: - centring the assembly group, comprising the stop ring (3) and the ferrule (4), during the assembly thereof on the fitting body (2) by way of the bevel (21) of the first internal contour (20) of the stop ring (3).