EP2184411B1 - Connection box to assemble sanitary fittings - Google Patents

Description

Technical area

The invention relates to a junction box for the assembly of sanitary fittings, comprising a holding part for fastening the junction box and a fluid-carrying part. The invention further relates to a method for producing such a junction box.

State of the art

Disturbing noises limit the comfort of living. Therefore, when building new buildings, more and more attention is paid to curbing sound propagation within the building. In this context, stricter standards have been adopted in recent years, for example the Swiss standard SIA 181 or DIN 18041.

Noise is generated among other things in drinking water and sewage pipes. In relation to drinking water pipes disturbing noises, especially in the range of supply lines to sanitary facilities such as kitchen or shower fittings, etc. About the attachment of the junction box for such a fitting, the sound waves on surrounding elements, such. B. the wall or an upstream panel are transmitted, which can lead to increased noise.

Until now, an installer himself was responsible for the sound insulation. Traditionally, to decouple the junction box from surrounding elements, the installer places sound-absorbing mats between the junction box mounting and the wall. Such sound insulation is often insufficient. In addition, there is a risk that the installer forgets to install a sound insulation or that the intended device is installed incorrectly by the installer. This causes the sound transmission is insufficient or even not attenuated.

From the CH 635 179 is generic junction box known; In particular, this document discloses a distancing device for pipe mounting a wall-mounted battery, which comprises a sound insulation.

Presentation of the invention

The object of the invention is to provide a connection box associated with the technical field mentioned above, which allows an improved insulation of noise generated in the region of a supply line of a sanitary fitting.

The solution of the problem is defined by the features of claim 1. According to the invention, in a junction box according to the invention between the fluid-carrying part and the holding part of the junction box, a sound-absorbing layer is present.

The holding part is used for mounting the junction box on real estate, especially on walls of buildings. It is attached to the fluid-carrying part, or holds the fluid-carrying part. The inventive arrangement ensures that sound waves are insulated at a transition from the fluid-carrying part to the holding part. Thus, the propagation of sound waves to that part of the property to which the junction box and thus the fitting are mounted, strongly contained.

Advantageously, the sound-insulating layer has areas with different cross sections. Such different cross sections may be provided such that at individual points, the distance between the holding part and the fluid-carrying part is reduced, for. B. to improve the mechanical attachment of the fluid-carrying part on the holding part. In particular, an inner surface of the sound-insulating layer has a structuring. It is thereby achieved that contact surfaces between the fluid-carrying part and the sound-insulating layer are reduced. In addition, due to the structuring of the inner surface, free spaces that can absorb displaced sections of the sound-absorbing layer due to the compression of the fluid-carrying part by the enclosing holding part are created.

Alternatively, such structuring may also be present on an outer surface or on both surfaces, instead of on the inner surface. In addition, alternatively, the sound-absorbing layer can have the same thickness in cross-section everywhere.

Advantageously, a hardness of the sound-insulating layer is both lower than a hardness of the holding part and as a hardness of the fluid-carrying part. Advantageously, the hardness of the sound-absorbing layer between 30 and 90 Shore A, in particular between 50 and 70 Shore A, preferably about 60 Shore A. This ensures that sound waves are optimally attenuated by the sound-absorbing layer and a sufficiently stable storage of the fluid-carrying part on Holding part is guaranteed. It should be noted that When fitting a valve, torques of up to 50 Nm or more act on the fluid-carrying part.

Alternatively, the hardness of the sound insulating layer may correspond approximately to the hardness of the holding part or the fluid carrying part. In addition, the hardness of the sound-absorbing layer may also be less than 30 Shore A or greater than 90 Shore A, in particular depending on the geometry of the holding part, the sound-absorbing layer and the fluid-carrying part. A lower hardness usually causes a greater attenuation of the sound waves. If the sound-insulating layer has a greater hardness, the fluid-carrying part is in turn held more stably on the holding part. Finally, it is possible that the hardness of the sound-insulating layer varies locally.

Advantageously, the sound-absorbing layer consists of an elastomer, in particular of TPE, EPDM, NBR or butyl, wherein the plastic used is sprayable. On the one hand, plastics, in particular TPE, EPDM, NBR and butyl, have a good sound-damping effect and, on the other hand, it is relatively easy and cost-effective to produce parts of very different forms from plastic. In particular, a surface of the sound-insulating layer can be structured. In addition, the sound-absorbing layer of sprayable plastic can be sprayed directly onto the holding part. This means a simplification of the production.

Advantageously, the fluid-carrying part forms an angle. This can be designed differently. Thus, angles between 30 ° and 180 °, in particular 30 °, 45 °, 90 °, 120 ° or 135 ° are conceivable. Angle parts are often used in junction boxes to allow a supply of a line of the control system along a wall, the free end of the junction box is directed vertically out of the wall and ready for attaching a fitting. In addition, junction boxes with an angle allow connections in corners.

Alternatively, just fluid-carrying parts are conceivable that serve as a support of a line of the control system.

Advantageously, the fluid-carrying part is designed as a tube. The pipe diameter may vary depending on the application. In particular, the common pipe diameters for fluid-carrying systems, preferably the standardized diameters of ½ inch and ¾ inch as well as 16 mm, 20 mm and 25 mm are conceivable.

Even though tubes usually have a circular cross section, tubes with other cross sections are also conceivable, in particular with elliptical, square or rectangular cross sections.

Advantageously, the fluid-carrying part consists of a copper alloy, in particular of a copper alloy with Si, Zn and at least 80 Ges .-% Cu. This copper alloy has proven to be a durable material for conducting liquids, especially water. It is also suitable for hot water. It is also easy to edit. Furthermore, the copper alloy is weldable with Si, Zn and at least 80% by weight of Cu. Further details of this suitable copper alloy can be found in European Patent Application no. 08 405 146.5 dated May 26, 2008 (R. Nussbaum AG).

Alternatively, the fluid-carrying part can also consist of another bronze alloy, such as red brass. But there are also metals such as stainless steel or copper or other copper alloys conceivable. Also suitable are fluid-carrying parts made of other materials such as plastic, in particular with or without glass fiber reinforced PPS, PPSU, PPA, or PSU. It is also a combination of different materials possible.

Advantageously, the junction box includes a canned base. Here, a first end of the can foot is flexible and a second, the first end opposite end dimensionally stable. The dimensionally stable end allows a firm connection of the fluid-carrying part with a to be mounted connection of the conduit system. Thanks to the flexible end of the can foot can also accommodate a supply line, which has a curved shape in the adjacent junction box area.

Alternatively, both ends can be formed dimensionally stable.

Advantageously, the can foot consists of a monomaterial, for example PE, wherein desired differences in flexibility are only brought about by the choice of geometry, in particular by different wall thickness or by means of a structure. As a result, for example, the first end of the can foot, in particular its free end, flexible and the second end are formed dimensionally stable. Parts made from mono-materials have the advantage that they can be produced in one process step. In addition, no joints between two different materials must be made. This simplifies the manufacture of the can foot.

Alternatively, the can foot may be composed of different materials. It is also possible to combine flexible materials with dimensionally stable materials.

The can foot advantageously comprises means for attachment to a base housing of the junction box. These can be z. B. be formed such that they form together with appropriate means on the base housing a bayonet fitting.

Advantageously, the box is designed as a double box. This means that a total of three connections, namely a supply line and two outlets, are provided. One of the leads leads to a fitting attached to the junction box, while the other lead is used to continue the lead. This allows the junction box to be installed in series in a piping system.

In addition, the invention can also be realized with other known types of junction boxes.

Advantageously, the junction box is modular. This means that different embodiments of the junction box from a selection of individual components, such as holding part, fluid-carrying part, can base can be assembled. Thus, components, such as a can leg, that are consistent for different applications and embodiments, respectively, may be employed in various embodiments. There are connecting points between individual Components equal, so that a modular design is possible. For example, a can foot of a single dose version can also be used in the double can. Instead of attaching the can leg to the holding part, two can feet of the same embodiment as in the single can, in the double can be attached to a connector instead of the holding part. It is also possible to combine different types of fluid carrying parts, for example angles with a 90 ° bend or with a 45 ° bend with holding parts with different fastening devices. This has the advantage that junction boxes can be assembled as needed. It can be used on an existing range of different components, which is extended by a component with sound-absorbing effect. In particular, it allows a person skilled in a mounting location to assemble the required embodiment of the junction box from individual components, wherein the sound-absorbing component is automatically integrated without additional effort.

Alternatively, a sound-insulating layer can also be provided in custom-made versions.

Advantageously, the holding part consists of at least two holding shells. In this case, these two holding shells can be individual parts or be integrally connected to each other, for example by means of a tab or a hinge. The design of the holding part in two or more holding shells allows easy assembly of the holding part with the fluid-carrying part. Preferably, the sound insulation is formed as an integral part of the holding part. The holding shells are preferably made of POM, but other materials can also be used, in particular PA with or without glass fiber reinforcement, PE, PP, PS, ABS or PVC.

Alternatively, the holding part may consist of one piece, wherein the sound-absorbing layer and the fluid-carrying part are already integrated.

Advantageously, the holding shells are held together by means of retaining rings. In this case, receptacles are provided in both holding shells, in which the retaining rings can be used when assembling the holding shells, or the retaining rings enclose both holders. This allows for easy assembly of the junction box without any glue, screws or other fasteners. This results in a longer service life, since no screws can solve or an adhesive can lose its effect. Advantageously, a plurality of retaining rings, in particular three retaining rings are present.

Alternatively, the holding shells can also be held together by means of adhesive, screws or a snap closure. It is also conceivable that the holding shells are welded together, in particular by means of an ultrasonic or laser welding process.

Advantageously, the sound-absorbing layer encloses the fluid-carrying part over a large area. By enclosing is meant that a lateral surface of the fluid-carrying part is covered by the sound-insulating layer. With a large area is meant that a substantial part of the lateral surface is enclosed. This is in contrast to a compound in which between two elements, for example, only one or more O-rings are present. In particular, the sound-absorbing layer surrounds at least 50%, preferably 75%, of the lateral surface of the fluid-conducting part. In this case, the sound-insulating layer may consist of a coherent piece or it may be separated into two or more parts. This has the advantage that on the one hand good soundproofing is ensured, but that the fluid-carrying part can be optimally held by the holding part.

Alternatively, the sound-absorbing layer can enclose a smaller proportion of the fluid-carrying part.

According to the invention, the holding part and the sound-insulating layer are produced in a two-component injection molding process. This has the advantage that any shapes of the junction box can be realized. In addition, the shape of the sound-absorbing layer can be easily adapted to the shape of the holding part.

According to the invention, a main body of the holding part is first produced by injection molding. Thereafter, the sound-absorbing layer is sprayed onto the holding part. By injecting both the holding part and the sound-absorbing layer in the same two-component process, a simplified production and optimum attachment of the sound-absorbing layer to the holding part results.

However, it is also possible to spray the sound-absorbing layer directly onto the fluid-conducting part. Furthermore, the holding shells and the fluid-carrying part may be assembled first, and then the sound-absorbing material may be injected into an intermediate gap to form the sound-insulating layer.

From the following detailed description and the totality of the claims, further advantageous embodiments and feature combinations of the invention result.

Brief description of the drawings

• Fig. 1 Eine Explosionszeichnung einer erfindungsgemässen Anschlussdose;
• Fig. 2 eine seitliche Ansicht der zusammengesetzten Anschlussdose ohne Winkel;
• Fig. 3 einen Schnitt durch die Anschlussdose ohne Winkel;
• Fig. 4 einen Schnitt durch die Anschlussdose mit eingesetztem Winkel; und
• Fig. 5 eine seitliche Ansicht der Anschlussdose mit Doppeldosenfuss. Grundsätzlich sind in den Figuren gleiche Teile mit gleichen Bezugszeichen versehen.

The drawings used to explain the embodiment show:

• Fig. 1 An exploded view of an inventive junction box;
• Fig. 2 a side view of the composite junction box without angle;
• Fig. 3 a section through the junction box without angle;
• Fig. 4 a section through the junction box with inserted angle; and
• Fig. 5 a side view of the junction box with double box foot. Basically, the same parts are provided with the same reference numerals in the figures.

Ways to carry out the invention

The FIG. 1 shows an exploded view of a junction box 100 according to the invention comprising a holding part 110, which is composed of two made of POM (polyoxymethylene) holding shells 111, 112 and is provided on its inner side with a sound-insulating layer 120. This sound-insulating layer 120 was sprayed directly onto the inside of the holding shells 111, 112 in a 2-component process of a thermoplastic elastomer (TPE), the hardness of this layer being smaller than that of the holding shells 111, 112. In addition, the connection box 100 comprises a fluid-conducting Part in the form of an angle 130 of silicon bronze, a first, second and third retaining ring 141, 142, 143 of POM and a tubular can foot 150, made of polyethylene (PE). The individual components of the junction box 100 are constructed as follows: The angle 130 consists of a first sub-pipe 131 having a first axis of symmetry A1 and a second sub-pipe 132 having a second axis of symmetry A2, wherein the two axes of symmetry A1 and A2 enclose an angle of 90 °. The two sub-pipes 131, 132 are connected to one another at a bend 133 of the angle 130. The inner surface of the angle 130 is hereinafter referred to that surface which comes into contact with a liquid which is guided at an angle 130. The outer surface is that surface which is opposite to the inner surface, wherein the end faces of the respective ends 131a, 132a of the partial tubes 131, 132 are not included.

The two holding shells 111, 112 are essentially mirror-symmetrical to one another. The holding shells 111, 112 each have a recess in the shape of a half-tube, designed such that the angle 130 is enclosed by half shells 111, 112, each half. As a result, in particular torques along one of the axes of symmetry A1, A2, which arise, for example, when mounting a line of a line system or a fitting at the angle 130, can be absorbed by the holding part 110. The sound insulating layer 120 formed on the holding shells 111, 112 is located between an inner surface of the recess of the half shells 111, 112 and the outer surface of the angle 130. The angle 130 facing Inner surface 121 of the sound insulating layer 120 is provided with a longitudinal structuring. This structuring of the inner surface 121 is essentially formed by ribs which extend along a flow direction of a liquid at an angle 130.

In the direction of the first axis A1, a fastening plate 113 or 114 in the form of a substantially rectangular plate is formed in the region of the bend 133 on both holding shells 111, 112, wherein the plate surfaces are perpendicular to the first axis A1. The attachment plates 113, 114 are provided so as to project laterally at the bend 133. In the protruding part of the mounting plates 113, 114 each have a plurality of holes which can be used for fastening the junction box 100 by means of screws (not shown) or other suitable fastening means on a wall of a building.

The holding shells 111, 112 enclose the angle 130 and are then held together by means of the three retaining rings 141, 142, 143, wherein in the holding shells 111, 112 of the holding part receptacles 115, 116, 117 are provided which receive the retaining rings 141, 142,143. The first retaining ring 141 encloses the first end 131a and is arranged coaxially with the first axis A1. The second retaining ring 142 encloses the second end 132a and is disposed coaxially with the second axis A2. The third retaining ring 143 is also arranged coaxially to the first axis A1, but the receptacle 117 of the third retaining ring 143 is located in the region of the fastening plates 113, 114. The receptacles 115, 116, 117 are configured as semicircular recesses in the retaining shells 111, 112.

At the second end 132a, the tubular can leg 150 made of PE is mounted coaxially with the second axis A2. In this case, a groove 142a is excluded in the second retaining ring 142 and on the can foot a nose 151 is present, which forms a kind of bayonet closure with the groove 142a.

On the holding shells 111, 112 are also laterally on the height of the first retaining ring 141 bulges 119a, 119b, each with a hole available to a front attachment of the junction box 100 by means of screws (not shown) or other suitable fasteners can serve on a wall of a building or other fastener.

The FIG. 2 shows the junction box 100 of FIG. 1 composed, but without the angle 130. FIG. 3 shows a cross section through the composite junction box without the angle 130 of FIG. 2 , FIG. 4 shows the same junction box the FIG. 3 , this time with the angle 130.

The junction box 100 is assembled as follows: The retaining shells 111 and 112 are placed on each other in a fitting manner so that the two half-tubes join together to form a tube and form the angle 130 (in FIG FIG. 2 and 3 not drawn) enclose. Thereafter, the three retaining rings 141, 142, 143 inserted into the receptacles 115, 116, 117. The dimensions of the recesses of the holding part 110, the sound-absorbing layer 120 and the angle 130 are such that a resistance must be overcome when enclosing the angle 130 with the holding shells 111 and 112, so that the retaining rings 141, 142, 143 in the receptacles 115, 116, 117 can be used. This resistance is caused by a slight deformation of the sound-absorbing layer 120. Since the material of the sound-insulating layer 120 is practically incompressible, this deformation is made possible by the structuring of the inner surface of the sound-insulating layer 120. Overcoming the resistance leads to a bias of the junction box, which contributes to the stability of the inclusion of the angle 130 within the holding part 110. After attaching the lead to the junction box 100, the can leg 150 can be slipped over the end 132a of the bracket 130 and attached to the retaining ring 142 by means of the bayonet lock.

Like in the FIG. 4 As can be seen, the thickness of the sound insulating layer 120 is tapered in a circumferential region near the first end 131a. The holding part 110 has at this point a radially circumferential rib 118, which fills the taper of the sound-absorbing layer. The thickness of the region of the sound absorbing layer which is in contact with the rib 118 is approximately 35% of the thickness of the adjacent regions at this point, namely approximately 0.5-0.6 mm, in contrast to approximately 1.5 mm. about the small-area rib 118 of the holding part 110 is transmitted to the angle 130 from the holding ring 141 via the holding part and the tapered sound-absorbing layer 120, a holding force. As a result, the angle 130 is additionally stabilized by the holding part 110 or the retaining ring 141, without the sound-insulating effect of the sound-absorbing layer being impaired.

An upper end 151 of the can foot 150, which is fastened to the retaining ring 142, has a thicker wall than a lower, free end 152 of the can foot 150. The thickening of the wall ensures that the upper, angle-facing end 151 is dimensionally stable and the lower, the angled end 152 is flexible. The lower end 152 of the can foot 150 is crimped inwardly to form a bead 153. This bead 153 serves to adapt the can foot 150 to the pipe diameter of the pipe guided therein.

Vibrations which propagate along the conduit of the fluid-carrying conduit system, which is connected to the angle 130 received in the holding part 110, or which have been generated in the region of the angle 130, are insulated by the sound-insulating layer 120 and only to a lesser extent by the holding part 110 transferred to the wall. Conversely, sound waves, which propagate in the wall as vibrations, first transmitted via the mounting plates 113, 114 and the bulges 119a, 119b on the junction box 100th But these vibrations are then also insulated in the sound-insulating layer 120 and only to a lesser extent transferred to the angle 130 and thus to the pipe system.

The FIG. 5 shows the junction box 100 with a Y-shaped branching part 200 of POM attached to the second end 132a of the bracket 130. This branching part 200 has at the upper end a first opening 201, which is connected to the end 132a. Facing downwards, facing away from the angle 130, in the branch part 200, the two openings 202, 203 are present. All openings 201, 202, 203 are connected via a common cavity 204. At the lower openings 202, 203 can now each one, the can foot 150 identical, can feet 252, 253 are attached. This is at the bottom two Openings 202, 203 each have a groove 202 a, 203 a corresponding to the groove 142 a, available. In this sense, the junction box 100 is modular.

In the embodiments, a clear separation between the body of the holding part and the sound-insulating layer is present, that is, it is clear where the holding part ends and the sound-absorbing layer begins. However, it is also conceivable that there is a smooth transition between the main body of the holding part and sound-insulating layer. This is particularly possible if both parts are made of the same type of plastic, they differ only by the degree of hardness, while the hardness of the actual holding part can continuously decrease to the actual sound-absorbing layer.

Different connection mechanisms of a fluid-carrying line to the corresponding end of the fluid-carrying part are conceivable. In question, inter alia, screw, plug or press connections.

In the illustrated embodiment, the sound insulating layer is visible at the ends of the junction box. This visibility can be enhanced by a suitable color choice. For this purpose, the plastic of the holder and / or the sound-absorbing layer can be colored. Conversely, the sound-insulating layer of the junction box can hardly or does not differ or the sound-absorbing layer is covered.

The structuring on the inner surface of the sound-absorbing layer can also be chosen differently. This structuring can also be located on the outer surface or on both surfaces. The structuring on the inner surface and on the outer surface may be different. In addition, a structuring of the sound-insulating layer can also correspond to structuring on the holding part and / or the fluid-carrying part. As a result, the strength with respect to rotational movements which can occur during assembly can be increased and tolerances of the production can be accommodated.

The embodiments treat junction boxes which are attached to a wall by means of screws or the like. But it is also conceivable that the junction box is poured directly into a wall. In this case, the junction box still consists of the three parts fluid-carrying part, holding part and in between a sound-insulating layer.

In addition to the mentioned in the exemplary embodiments can base with a bent, lower end and a can foot is conceivable, the lower end is not bent. Thus, the end may have a normal wall thickness. It is also possible. to provide the lower end with a thicker wall. The end can be both flexible and rigid. Such a thicker wall can take over the function of the bent end.

The mobility of the lower end of the can foot is achieved in the embodiments in that the wall of the can foot is thinner than the rigid, upper end. The change from the thicker wall to the thinner wall can, as can be seen in the drawings, be effected discretely in one or more stages. This change can also take place continuously. The change can take place both over the entire length of the can foot or even only over individual parts of the length of the can foot. It is also conceivable that a segmentation of the can foot of alternating movable and rigid segments is present.

In the exemplary embodiment, a rib is formed in the holding shells which fills a taper of the sound-absorbing layer. It is conceivable that the sound-insulating layer is completely interrupted at this point and the rib has direct contact with the fluid-carrying part. On the other hand, it is entirely possible to dispense with such a rib or rejuvenation. It is also possible that this rib does not circulate continuously as in the embodiment, the fluid-carrying part, but is formed only piecewise. In this case, both a piecewise tapering of the sound-insulating layer may be present as well as the sound-absorbing layer be interrupted piecewise.

In summary, it should be noted that a junction box is provided by the invention, which allows an improved insulation of noise generated in the region of a supply line of a sanitary fitting.

Claims (15)

1. Connection box (100) for assembling sanitary fittings, comprising a retaining part (110) for securing the connection box (100) and a fluid-conveying part (130), wherein a sound-damping layer (120) is present between the fluid-conveying part (130) and the retaining part (110), characterized in that the retaining part and the sound-damping layer are produced in a two-component injection process, wherein either a main body of the retaining part is first produced in an injection-moulding process and subsequently the sound-damping layer is injected onto the retaining part, or both the retaining part and the sound-damping layer are injected in the same two-component injection process.
2. Connection box (100) according to Claim 1, characterized in that the sound-damping layer (120) has regions of different cross section, in particular in that an internal face (121) of the sound-damping layer (120) is structured.
3. Connection box (100) according to Claim 1 or 2, characterized in that a hardness of the sound-damping layer (120) is less than a hardness of a region of the retaining part (110) that is in contact with the layer, and less than a hardness of the fluid-conveying part (130).
4. Connection box (100) according to Claim 3, characterized in that the sound-damping layer (120) has a hardness of 30-90 Shore A, in particular 50-70 Shore A, preferably approximately 60 Shore A.
5. Connection box (100) according to one of Claims 1 to 4, characterized in that the sound-damping layer (120) is made of an elastomer, in particular of TPE, EPDM, NBR or butyl.
6. Connection box (100) according to one of Claims 1 to 5, characterized in that the fluid-conveying part (130) forms an angle.
7. Connection box (100) according to one of Claims 1 to 6, characterized in that the fluid-conveying part (130) is made of metal, in particular a copper alloy, in particular a copper alloy having Si, Zn and at least 80wt% of Cu.
8. Connection box (100) according to one of Claims 1 to 7, characterized in that it comprises a box foot (150), wherein a free end (152) of the box foot (150) is flexible and an end (151) opposite the free end (152) is dimensionally stable.
9. Connection box (100) according to Claim 8, characterized in that the box foot is made of a monomaterial, wherein a wall of the box foot (150) comprises regions of different wall thickness, so as to achieve regions of different flexibility.
10. Connection box (100) according to one of Claims 1 to 9, characterized in that the connection box (100) is designed as a double box.
11. Connection box (100) according to one of Claims 1 to 10, characterized in that the retaining part (110) consists of at least two retaining shells (111, 112).
12. Connection box (100) according to Claim 11, characterized in that the retaining shells (111, 112) of the connection box (100) are held together by means of retaining rings (141, 142, 143).
13. Connection box (100) according to one of Claims 1 to 12, characterized in that the sound-damping layer (120) encloses the fluid-conveying part (130) over a large area.
14. Method for producing a connection box (100) according to one of Claims 1 to 13, characterized in that the retaining part (110) and the sound-damping layer (120) are produced in a two-component injection process.
15. Method according to Claim 14, characterized in that a main body of the retaining part (110) is first produced in the injection process and subsequently the sound-damping layer (120) is injected onto the retaining part (110).

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