FRICTION DISC FOR A FALSE-TWIST DEVICE

Abstract

Friction disc for a false-twist device, comprising an annular hub, on which it is possible to fix a circular race formed by a polyurethane (PU) layer and has a minimum wall thickness required for a secure interlocking fit, the hub having a circumferential support ring and a central hole, by which the friction disc is fixed on one of the shafts of the false-twist device. To ensure better dimensional and form stability over a long service life of the friction disc, the formed race fixed on the hub is ground according to a predefinable profile such that the flanks of the race have a predefinable width dimension following the grinding process, and/or in that the hub has, at a spacing from the support ring, a circumferential shoulder for abutment for the fixable PU layer, a cross-sectional width of the shoulder being smaller than a cross-sectional width of the support ring.

Claims

1. A friction disc for a false-twist device, comprising an annular hub, on which a circular race is fixable that is formed by a polyurethane (PU) layer and has a minimum wall thickness required for a secure interlocking fit, the hub having a circumferential support ring and a central hole, by which the friction disc is fixable on one of the shafts of the false-twist device, characterized in that the formed race fixed on the hub is ground according to a predefinable profile such that the flanks of the race have a predefinable width dimension following the grinding process; and/or the hub has, at a spacing from the support ring, a circumferential shoulder for abutment for the fixable PU layer, a cross-sectional width of the shoulder being smaller than a cross-sectional width of the support ring.

2. The friction disc according to claim 1, characterized in that the width dimension of the flanks of the formed race fixed on the hub is equal to or smaller than the maximum cross-sectional width of the hub.

3. The friction disc according to claim 2, characterized in that the wall thickness of the PU layer of the race is minimized to the minimum wall thickness required for the secure interlocking fit.

4. The friction disc according to claim 1, characterized in that the hub is made of a plastic material.

5. The friction disc according to claim 4, characterized in that the hub is made of polybutylene terephthalate (PBT).

6. The friction disc according to claim 1, characterized in that the PU layer of the formed race fixed on the hub has a hardness of at least 85 Shore A.

7. The friction disc according to claim 1, characterized in that the hub has at least one passage which passes through the hub in order to channel, in a predefined manner, the air flowing through the at least one passage during rotational operation of the friction disc.

8. The friction disc according to claim 7, characterized in that the at least one passage is designed such that the air flowing through the at least one passage during rotational operation of the friction disc leads towards an additional friction disc of the false-twist device arranged adjacently to the friction disc.

9. The friction disc according to claim 7, characterized in that the hub forms a fan shape having a plurality of passages, which are separated from one another by a partition having a predetermined blade geometry for the defined channeling of the air flowing therethrough.

10. The friction disc according to claim 8, characterized in that the hub forms a fan shape having a plurality of passages, which are separated from one another by a partition having a predetermined blade geometry for the defined channelling of the air flowing therethrough.

11. A false-twist device comprising a bearing block having at least one rotatably mounted shaft comprising at least two friction discs arranged along the shaft at a spacing from each other thereon, characterized in that one of the friction discs is a friction disc according claim 8.

12. A false-twist device comprising a bearing block having at least one rotatably mounted shaft comprising at least two friction discs arranged along the shaft at a spacing from each other thereon, characterized in that one of the friction discs is a friction disc according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further details of the invention can be taken from an embodiment example presented below on the basis of the figures, in which:

[0035] FIG. 1 is a schematic perspective view of a false-twist device having a plurality of rotatably mounted shafts, on each of which three friction discs are fixed according to an embodiment example,

[0036] FIG. 2 is a plan view of the hub of a friction disc according to an embodiment example,

[0037] FIG. 3 shows the hub of a friction disc according to section B-B of FIG. 2,

[0038] FIG. 4 shows the hub of the friction disc according to section A-A of FIG. 2,

[0039] FIG. 5 is a section through a friction disc according to an embodiment example, comprising a hub of which the support ring is enclosed by a race formed by a PU layer,

[0040] FIG. 6 is a perspective view of a friction disc according to an embodiment example to approximately the original scale,

[0041] FIG. 7 is a section through a friction disc according to an embodiment example, comprising a hub designed in a fan shape, and

[0042] FIG. 8 is a schematic partially sectional view of a fan blade of the friction disc shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The following description of the embodiments of the present invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. The following description is provided herein solely by way of example for purposes of providing an enabling disclosure of the invention, but does not limit the scope or substance of the invention.

[0044] FIG. 1 is a schematic perspective view of an embodiment example of a false-twist device 1, as used, for example, in texturing machines in the context of the production of crimped textile threads 3.

[0045] As is known, false-twist devices 1 of this kind in each case have a bearing block 2 having a plurality of rotatably mounted shafts 4, which at their ends are connected to a drive (not depicted in FIG. 1). Drives of this kind for false-twist devices are known, however, and are described in relative detail in European Patent Publication EP 0 744 480 A1, for example.

[0046] As can also be seen in FIG. 1, the shafts 4, each of which is equipped with friction discs 5, are arranged such as to form a triangle. In the embodiment example, each of the shafts 4 has three friction discs 5 arranged one behind the other and spaced apart in the running direction F of the thread 3.

[0047] The exact configuration of a friction disc 5 according to an embodiment example is explained in greater detail below on the basis of FIGS. 2-6.

[0048] Each of FIGS. 2-4 shows a hub 6, made of plastic material, of a friction disc 5 according to an embodiment example to an enlarged scale and in different views.

[0049] As can be seen from FIG. 2, which is a plan view of a hub 6, the hubs 6 of such friction discs 5 each have an annular main body 13, which is created from a plastic material using an injection moulding method and has a central hole 8. The diameter of this central hole 8 is tailored to the diameter of the shafts 4 of the false-twist device 1, such that, once produced, friction discs 5 can be positioned on the shafts 4 of a false-twist device 1 without any problems.

[0050] As can also be seen, hubs 6 of this kind in each case have an outer, circular support ring 7 and a shoulder 11, which is likewise circumferential and is spaced apart from said support ring 7. In the main body 13 of the hub 6, a plurality of locking openings 12 (of which there are eighteen in the embodiment example) are also arranged between the support ring 7 and the shoulder 11. As explained below, these locking openings 12 are used to fix a race 9 (depicted in FIGS. 5 and 6) of the friction disc 5, said race consisting of a PU layer.

[0051] Each of FIGS. 3 and 4 is a section through the hub 6 of a friction disc 5. FIG. 3 shows the hub 6 according to section B-B of FIG. 2, whereas FIG. 4 depicts the hub 6 according to section A-A of FIG. 2.

[0052] As can be seen from FIGS. 3 and 4, the main body 13 of the hub 6 has its maximum cross-sectional width BN in the region of the central hole 8, whereas the cross-sectional width BS of the outer, circumferential support ring 7 of the hub 6 is slightly less than the maximum cross-sectional width BN of the hub 6.

[0053] In addition, the main body 13 of the hub 6 has a shoulder 11, which is likewise circumferential and is arranged at a spacing from the support ring 7, the cross-sectional width BA of said shoulder being slightly less than the cross-sectional width BS of the support ring 7.

[0054] As can be seen in particular from FIGS. 2 and 4, there are also a number (eighteen in the embodiment example) of so-called locking openings 12 arranged in the region between the support ring 7 and the shoulder 11, which locking openings make it possible to properly fix a race 9 (not depicted in FIGS. 2-4) made of PU in place.

[0055] FIG. 5 is a section through a finished friction disc 5 according to an embodiment example, i.e. a friction disc 5 having a hub 6 that is made from PBT using an injection moulding method and is enclosed by a race 9, which was also created in an injection molding method.

[0056] The race 9, which consists of a PU layer, encompasses the support ring 7, abuts the shoulder 11 and is ground according to a predefinable profile 14, has a substantially uniform, relatively thin profile thickness. In addition, the flanks 10 of the race 9 are ground to a predefined width dimension BFL in the region of the support ring 7. The width dimension BFL of the flanks 10 of the race 9 is slightly smaller than the maximum cross-sectional width BN of the hub 6.

[0057] FIG. 6 is a perspective view of a friction disc 5 according to an embodiment example to approximately a 1:1 scale. As already explained above, this friction disc 5 has a hub 6, made of a plastic material and having a central hole 8, and a race 9, which is likewise made of a plastic material. The hub 6, manufactured using an injection moulding method, advantageously consists of PBT (polybutylene terephthalate) 40% GK natural, whereas the race 9 consists of a PU layer which preferably has a hardness of at least or exactly 85 Shore A.

[0058] FIG. 7 is a section through a friction disc 5 according to a further preferred embodiment example, which is designed almost identically to the friction disc 5 according to FIG. 6, with the only difference being the configuration of the hub 6. Due to the identical configuration, marked by the same reference signs, reference is made to the above description.

[0059] The hub 6 according to this preferred embodiment example is formed as an axial fan, the main carrier portion between the central hole 8 and the shoulder 11 having a plurality of fan blades 15 arranged in a circular manner, in particular evenly distributed, around the central hole 8, said fan blades having an aerodynamic profile for the defined channelling of the ambient air from one side of the friction disc 5 to the other side. In this context, FIG. 8 is a schematic partially sectional view of a fan blade 15 of the friction disc 5 according to FIG. 7 in a perspective from the central hole 8 towards the support ring 11.

[0060] The friction disc 5 according to this preferred embodiment example promotes a cooling action of both the friction disc 5 and the false-twist device in which a friction disc 5 of this kind is used. For example, the friction disc 5 according to this embodiment example can be used in a false-twist device 1 shown in FIG. 1. In that case, it would be advantageous to arrange the friction disc 5 on the shaft 4 at the first position in the thread running direction F, i.e. at a position the furthest away from the bearing block 2 for the friction discs 5 to be arranged. Upon rotation of the friction disc 5 equipped with the hub 6 designed in a fan shape, an arrangement of that kind enables cooling in friction discs 5 arranged downstream in the thread running direction F, and in the bearing block 2 in which the drive for the shafts 4 can be housed. This has an advantageous impact on both the wear and the service life of the friction discs 5.

LIST OF REFERENCE SIGNS

[0061] 1 False-twist device [0062] 2 Bearing block [0063] 3 Thread [0064] 4 Shaft [0065] 5 Friction disc [0066] 6 Hub [0067] 7 Support ring [0068] 8 Central hole [0069] 9 Race [0070] 10 Flank [0071] 11 Shoulder [0072] 12 Locking opening [0073] 13 Main body [0074] 14 Profile [0075] 15 Fan blade [0076] F Thread running direction [0077] BS Cross-sectional width/support ring [0078] BFL Width dimension/flanks [0079] BN Max. cross-sectional width/hub [0080] BA Cross-sectional width/shoulder

[0081] It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements.