ASSEMBLY GROUP FOR A PRESS FITTING FOR A PIPE CONNECTION

Description

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

[0002] The invention further relates to a press fitting for a pipe connection, comprising a fitting body and such an assembly group.

[0003] Press fittings for pipe connections are known from the state of the art. For example,

[0004] DE 10 2018 109 555 B3 a press fitting 101 for a pipe connection is known, which is used in the Figure 12 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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 that 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, and / or in which damage to individual parts, such as the fitting body, can be reduced or avoided during production.

[0009] The invention is defined in the appended claims.

[0010] According to a first aspect of the disclosure, a press fitting for a pipe connection is disclosed. The press fitting comprises a fitting body for connecting the press fitting to a pipe, a substantially cylindrical press sleeve having a pressing region and secured to the fitting body, and a stop ring secured to the press sleeve, which delimits the pressing region in an axial direction of the press sleeve. The stop ring has a substantially cylindrical inner contour with protruding first regions and second regions recessed relative to the first regions. The first regions of the first stop ring clampingly engage around an outer contour of the press sleeve. The second regions of the stop ring are spaced apart from the outer contour of the press sleeve.

[0011] A stop ring designed in this way, with an inner contour featuring protruding and recessed areas, enables the creation of a secure clamp connection, even taking into account possible tolerances of a press fitting. This type of clamping securely holds the stop ring to a press sleeve, even before the press sleeve is mounted on the actual fitting body. This ensures, among other things, that the stop ring does not accidentally detach from the press sleeve before the press sleeve is mounted on the fitting body and before pressing.

[0012] According to the claim, the press sleeve has a predetermined outer diameter d 3 with a predetermined tolerance range. A clear inner diameter d 1 between the first areas is smaller than a predetermined outer diameter d 3 of the press sleeve less a negative tolerance, and a clear inner diameter d 2 between the second areas is larger than the predetermined outer diameter d 3 plus a positive tolerance. The predetermined tolerance range is approximately 1% of a diameter of a pipe to be connected with the press fitting and / or at least 0.2 mm. The clear inner diameter d 1 between the first areas is approximately 0.5% and / or at least 0.1 mm smaller than the predetermined outer diameter d 3 less the negative tolerance. And the clear inner diameter d 2 between the second areas is approximately 0.5% and / or at least 0.1 mm larger than the predetermined outer diameter d 3 plus the positive tolerance.

[0013] In at least one embodiment, the fitting body has a circumferential groove, and the compression sleeve has, at a fitting-side (or proximal), first axial end, a first projection pointing radially inward, which engages in the groove when secured to the fitting body, so that the compression sleeve is directly fastened to the fitting body. Such a direct connection between the compression sleeve and the fitting body, for example by locking the first projection with the circumferential groove, increases the stability of the press fitting after the compression sleeve has been mounted on the fitting body, for example, against impacts from a lateral direction.

[0014] In at least one embodiment, the compression sleeve has one or more slots extending from the first axial end toward the compression region. Such slots facilitate the application of the compression sleeve to the fitting body. The recessed, second regions of the stop ring facilitate the bending of the first end of the compression sleeve during its assembly on the fitting body.

[0015] According to one possible embodiment, the first and second regions are connected by curved transition areas. Such a shape is relatively easy to manufacture and simultaneously ensures secure clamping of the stop ring to the compression sleeve.

[0016] According to an alternative embodiment, the second regions are formed by a substantially cylindrical inner surface of the stop ring, and the first regions are formed by webs protruding from the inner surface. Such a design is particularly material-efficient during production and also ensures secure clamping of the stop ring.

[0017] According to a second aspect of the disclosure, an assembly group for the press fitting according to the first aspect is described. The assembly group comprises a substantially cylindrical press sleeve with a pressing region and a stop ring fixed 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 substantially cylindrical inner contour with protruding first regions and second regions recessed relative to the first regions, wherein the first regions of the stop ring clampingly engage around an outer contour of the press sleeve and the second regions of the stop ring are spaced from the outer contour of the press sleeve.

[0018] In such an assembly, a stop ring is securely attached to a press sleeve. This allows the assembly to be easily stored and, if necessary, transported before being applied to the corresponding fitting body of a press fitting.

[0019] Further advantageous embodiments are disclosed in the appended claims and the following detailed description of embodiments.

[0020] The invention will be explained in detail below using various exemplary embodiments with reference to the attached figures. Like reference numerals designate like 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 1in 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] In contrast, a second inner diameter d 2 between two opposite, most recessed parts of the second regions 16 is dimensioned so large that a clear distance always 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 for a maximum outer diameter of the compression sleeve 4 within the tolerance range, and a maximum clearance of 0.35 mm remains for a minimum outer diameter of the compression sleeve 4.

[0031] 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.

[0032] 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.

[0033] 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 its 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] For example, 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. Alternatively, it is also possible to design the element 26 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 inwards 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.

[0038] 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.

[0039] 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.

[0040] 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°.

[0041] As a result, the segments 34 of the press sleeve 4 formed between the slots 10 of the press sleeve 4, with the lips 8 formed thereon, expand slightly one after the other when locked together. 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. 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 by offsetting or tilting the connection area 6 into the assembly group 28, compared to a press-in force of approximately 2100 N with coaxial pressing, which significantly facilitates the installation 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, especially when plastic materials are used for the fitting body 2.

[0042] 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.

[0043] Figure 11 shows schematically the steps of a method for assembling a press fitting 1.

[0044] First, in step S1, a compression sleeve 4 with a predetermined nominal diameter is provided. According to the invention, 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.

[0045] In a subsequent step S2, a stop ring 3 is placed onto the press sleeve 4 at a first axial end 9. Preferably, it is fastened to the press sleeve 4, for example by the inventive provision of raised first regions 15 and recessed, second regions 16, which lead to a clamping of the stop ring 3 on the press sleeve 4. Alternatively, other connections not according to the invention, in particular form-fitting connections, are also possible. In a further step S3, the thus-produced assembly group 28 of the press sleeve 4, 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.

[0046] 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 controlling a placement machine or a press die or, as previously described using 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.

[0047] 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.

[0048] 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

[0049] 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. Mounting unit (28) for a press fitting (1), having: - a substantially cylindrical press sleeve (4) with a pressing region (11), wherein the press sleeve (4) has a predetermined external diameter d3 with a predetermined tolerance range; and - a stop ring (3) which is fixed at a first axial end (9) of the press sleeve (4) and delimits the pressing region (11) in an axial direction of the press sleeve (4), wherein - the stop ring (3) has a substantially cylindrical inner contour (14) with projecting first regions (15) and second regions (16) which are recessed relative to the first regions (15), - a clear internal diameter d1 between the first regions (15) is smaller than the predetermined external diameter d3, less a negative tolerance, so that the first regions (15) of the stop ring (3) engage in a clamping manner around an outer contour of the press sleeve (4), and - a clear internal diameter d2 between the second regions (16) is greater than the predetermined external diameter d3, plus a positive tolerance, so that the second regions (16) of the stop ring (3) are located at a distance from the outer contour of the press sleeve; - wherein the predetermined tolerance range is at least 0.2 mm and in particular approximately 1% of a diameter of a pipe to be connected to the press fitting; - the clear internal diameter d1 between the first regions (15) is approximately 0.5% and / or at least 0.1 mm smaller than the predetermined external diameter d3, less the negative tolerance; and - the clear internal diameter d2 between the second regions (16) is approximately 0.5% and / or at least 0.1 mm greater than the predetermined external diameter d3, plus the positive tolerance.

2. Press fitting (1) for a pipe connection, having: - a fitting body (2) for connecting the press fitting (1) to a pipe; and - a mounting unit (28) according to Claim 1, wherein the substantially cylindrical press sleeve (4) of the mounting unit (28) is fixed to the fitting body (2).

3. Press fitting (1) according to Claim 2, wherein - the fitting body (2) has a circumferential groove (7); and, - at a fitting-side first axial end (9), the press sleeve (4) has a first projection, which points inwards in the radial direction and, when fixed to the fitting body (2), engages in the groove (7), so that the press sleeve (4) is fastened directly to the fitting body (2).

4. Press fitting (1) according to Claim 3, wherein the first projection, which points inwards in the radial direction, is designed in the form of a lip (8).

5. Press fitting (1) according to Claim 3 or 4, wherein, at a pipe-side second axial end (12), the press sleeve (4) has a second projection, which points outwards in the radial direction and delimits the pressing region (11) in the direction of the second axial end (12) of the press sleeve (4).

6. Press fitting (1) according to Claim 5, wherein the second projection, which points outwards in the radial direction, is designed in the form of a flange (13).

7. Press fitting (1) according to any one of Claims 3 to 6, wherein the press sleeve (4) has one or a plurality of slots (10), which extend from the first axial end (9) in the direction of the pressing region (11).

8. Press fitting (1) according to any one of Claims 3 to 7, wherein - the stop ring (3) is arranged at the first axial end (9) of the press sleeve (4) and delimits the pressing region (11) in the direction of the first axial end (9) of the press sleeve (4); and - the stop ring (3) has a third projection, which points inwards in the radial direction and, when fixed to the fitting body (2), engages in the groove (7) of the fitting body (2).

9. Press fitting (1) according to Claim 8, wherein the third projection, which points inwards in the radial direction, is designed in the form of an open base surface (23).

10. Press fitting (1) according to any one of Claims 2 to 9, wherein the first regions (15) are connected to the second regions (16) by curved transitional regions (30).

11. Press fitting (1) according to any one of Claims 2 to 9, wherein the second regions (16) are formed by a substantially cylindrical inner surface (24) of the stop ring (3), and the first regions (15) are formed by webs (25) protruding from the inner surface (24).

12. Press fitting (1) according to any one of Claims 2 to 11, wherein the attachment ring (3) comprises a plastic material, in particular a polymer material.

13. Press fitting (1) according to any one of Claims 2 to 12, wherein the press sleeve (4) comprises a metal substance, in particular stainless steel.

14. Press fitting (1) according to any one of Claims 2 to 13, wherein the fitting body (2) comprises a metal substance and / or a plastic material substance.

15. Press fitting (1) according to Claim 14, wherein the fitting body (2) comprises a polymer substance.