EP0943022B1 - False twist device - Google Patents

Description

The invention relates to a false twister for a synthetic multifilament thread for use in false twist texturing machines according to the generic term of claim 1.

With false twist texturing machines, one starts from the principle that the synthetic multifilament thread running through a false twist in a twisted state with e.g. offset and in excess of 2,000 rpm heated in this twisted state to the plasticization limit and then back to a temperature below the transition point first order, is cooled.

A false twister, which is from the US, is used for swirling 4,235,071 (Bag. 1110) is known. The false twister consists of three Sets of rotating in the same direction arranged on an axis Slices. The axes are on the corner points of an equilateral polygon arranged so that the disks overlap in the center of the polygon. The thread is in the center of the polygon by the false twister guided, the thread touching the peripheral surface of the rotating discs and is thus twisted. The shape given by the thread by heating and then cooling in the false twist texturing machine fixed, so that a crimp in the Thread is retained.

It should be borne in mind that in false twist texturing machines today preferably threads made of polyester, in particular polyethylene terephthalate, Polyamide 6 (Perlon) or Polyamide 6.6 (Nylon) can be processed. there the threads are presented as pre-oriented yarns. This pre-oriented Yarns are spun at high speed and are therefore on the Texturing machine still a small stretch in the ratio of less than 2: 1 for polyester, preferably less than 1.8: 1 for Polyamides preferably subjected to less than 1.3: 1.

With this stretching, polyester threads are opened in the heating zone Temperatures from 190 ° C to 210 ° C, nylon threads from 190 ° C to 205 ° C and Subject to perlon threads of approx. 170 ° C.

The technological requirement that the effective thread temperature in the Heating zone must exceed 180 ° C, preferably 200 ° C, leads to growing thread speeds and the known cooling devices cause the thread with an excessive temperature in the false twister comes in. The thread temperature can be changed when entering the False twister> 100 ° C.

The increased thread speeds in the false twist require higher thread tensions in order to achieve a stable texturing process receive. Such thread tensions can be increased Stretch ratio, which in turn leads to undesirable changes of the thread properties (especially lower elongation).

Accordingly, it is an object of the invention to provide a false twister at the beginning mentioned type in such a way that within a false twist zone a false twist texturing machine a stable thread run at thread speed of over 1,000 m / min, in particular over 1,200 m / min, can be achieved.

The object is achieved by a false twister with the Features of claim 1 solved.

The invention is based on the finding that, while maintaining a stable process with increased thread speed, the thread tension has to be raised less when the disks of the false twister have a correspondingly large radius on their peripheral surfaces contacted by the thread. In terms of measurement technology, a reduction in the coefficient of friction is found. This is surprising insofar as the radius of the disk shell - seen in the radial section of the disks - is unusually large, so that due to the resulting extension of the contact distance of the thread wetted with finishing, an increase in the coefficient of friction or the thread tension (Euler's law) can be expected is, while according to Eitelwein's law it can be expected that the coefficient of friction or thread tension depends exclusively on the wrap angle, but not on the radius or length of the wrapped surface. In fact, the reduction in the coefficient of friction or the thread tension is based on the reduced internal friction in the thread caused by a larger radius of curvature. The internal friction in the thread results from the alternating bending load on the thread inside the false twister. These alternating bending loads can be reduced accordingly by increasing the circumferential surface radii. Since the alternating bending load of the thread increases with a smaller thread diameter, it has been found that the radius r of the circumferential surface must have a certain size in relation to the diameter d _{F of} the twisted thread, which is at least 35 times the diameter d _{F of} the twisted thread. In the following, "circumferential surface" means the surface on the disc that is contacted by the thread, with the outer surface the entire surface of the disc (without the end faces).

In the false twist texturing machines, threads are preferably made today Machined polyester or polyamide. Polyamide threads are preferred with titers <170 dtex and polyester threads also with titers from> 170 dtex processed. The development of the invention according to claim 2 is therefore used especially for processing polyester threads.

In order to process polyamide threads advantageously, the invention is Execute false twist according to claim 3.

In a particularly preferred embodiment of the false twister according to the invention is the circumferential surface radius r in relation to the disc height h formed such that the center of the circumferential surface radius outside the center plane of the disc preferably between the leading edge and the Middle plane of the disc lies. This can be used especially for discs with high Coefficients of friction are achieved that the peripheral surface is substantially the same the outer surface and the thread is not over the edges of the end faces running. Due to the twist, the thread is wrapped around the disc so influenced that the thread on the peripheral surface of the disc with with a larger helix angle and with the circumferential surface runs out at a smaller helix angle. Due to the asymmetrical structure the disc is thus only a shorter section of the inlet side Torus area as available on the outlet side. With this training the false twister, which is preferred for discs made of high-friction Materials such as polyurethane or rubber is used, the washers can only be used in a certain installation position. The end faces are to avoid installation errors during assembly such discs marked (for example with printing, ring groove, etc.).

In order to achieve the required twist (from for example, more than 2,000 U / m) with sufficient process stability in the Introducing thread are the discs of a preferred development of the False twister made from a heat-resistant elastomer. The The heat resistance of the elastomer enables a thread temperature of more than 100 ° C on the panes.

In a particularly preferred development of the invention, the Discs made of a heat-resistant rubber, especially with hydrogen saturated nitrile rubber. This material is particularly advantageous since it is also particularly wear-resistant with high heat resistance and also good rubbing properties compared to synthetic multifilament threads having. It is therefore for processing the threads at high Thread speeds and high temperatures are particularly suitable.

An embodiment is shown below with reference to the accompanying Drawings described in more detail.

Fig. 1

schematisch einen Falschdrallgeber;

Fig. 2 und 3

die Scheibe eines Falschdrallgebers im Schnitt sowie den Fadenlauf über die Scheibe.

They represent:

Fig. 1

schematically a false twister;

2 and 3

the disc of a false twister in the cut and the thread run over the disc.

2 schematically shows an embodiment of the invention False twist shown. The false twister could, for example, in the Texturing machine according to EP 0 641 877 (Bag. 2147) can be used. Consequently reference is made to the content of this publication.

The false twister consists of three parallel shafts 4.1, 4.2 and 4.3. The shafts 4.1, 4.2 and 4.3 are rotatable in at one end (drive end) a bearing block 1 mounted and arranged such that the waves in each a corner point of an equilateral triangle. On the wave 4.1 is a set of discs 3 is attached from the free end to the shaft 4.1. The Disc set 3 consists of the individual spaced apart Discs 3.1, 3.2 and 3.3. On the shaft 4.2 is the disc set 6 and on the shaft 4.3 the disc set 5 is attached. The disc set 6 and the disc set 5 also consist of three spaced apart arranged individual disks. The washers of disk sets 3, 5 and 6 overlap in the central area of the wave formed equilateral triangle. The shafts 4.1, 4.2 and 4.3 are at the drive end connected to a drive, not shown here. By the The shafts and thus the disks of disk sets 3, 5 are driven and 6 driven in the same direction. The drive could, for example, by a Belt drives take place as known from EP 0 744 480 (Bag. 2322). It To this extent, reference is made to this publication.

The number of disks within a disk set is exemplary. It more or less discs can be attached to a shaft.

A thread guide 7 is arranged on the inlet side of the false twister. Via the thread guide 7, the thread 2 reaches the overlap area in the essentially in the area of the center of this equilateral triangle. The Thread 2 then becomes helical to the drive side of the false twister guided. Here the discs of disc sets 3, 5 and 6 looped around the circumference of the thread. The thread becomes this with a predetermined withdrawal speed by the false twister downstream delivery plant deducted. Thus, the thread 2 is a False twist impressed, the one upstream of the false twister False twist zone is fixed. To the thread tension losses within the To reduce false twist, the discs have a relatively large Radius on their peripheral surface.

As shown in Fig. 2, the peripheral surface of the disc is like the surface the zone of a sphere or a toroid with a constant radius. FIG. 2 is a radial section through a disk of FIG. 1 False twist shown shown. In the embodiment according to the invention of the disk, the radius r of the peripheral surface 11 is of such a size that that the entire circumferential surface is uniform in the area of the disc height h is curved. In Fig. 2 is the disk 3.1 of the one shown in Fig. 1 as an example False twist shown. In this example the disc is 3.1 symmetrical. The center point M of the circumferential surface radius r lies in the central plane 9 of the disk 3.1. The peripheral surface 11 is the Thread 2 is looped over the entire disc height h. thread 2 runs on the leading edge 8 on the peripheral surface 11. On the bottom the disc, the thread 2 leaves the peripheral surface 11 via the trailing edge 10. Here are the entry angle α of the thread 2 on the entry side and the outlet angle α on the outlet side of the disk 3.1 is the same size.

According to the invention, the circumferential surface radius r is at least 35 times as large as the thread diameter d _{F of} the twisted thread. The thread diameter d _F can be calculated from the thread titer, the crimp and the density of the thread material. This means that the friction discs can be optimally designed for each thread diameter. For example, for a thread made of polyester with a thread titer of 335 dtex, the thread diameter d _F can be determined to be 0.198 mm. According to the invention it follows that the radius r of the peripheral surface should have a minimum size of 8 mm. In another example of a thread made of polyamide with a thread denier of 110 dtex, the thread diameter d _{F is} calculated to be 0.123 mm. According to the invention, the disks of the false twister must have a radius r of, for example, 5 mm on their peripheral surfaces in order to maintain the factor 35.

In Fig. 3, another embodiment of a disc is shown as it 1 could be used in the false twist unit. In the case of FIG. 3 disc shown is not the center M of the circumferential surface radius r in the central plane 9. The peripheral surface 11 is within the disc height h asymmetrical. Especially for disc materials with high The twist on the thread causes the entry angle and the outlet angle of the thread is uneven. As a rule, the inlet angle α1 on the inlet side of the disc is smaller than the outlet angle α2 on the outlet side of the disc. To over the entire height h of the disc to get even contact of the thread on the peripheral surface 11, therefore the center must correspond to the angular division on the central plane 9 can be moved. The total wrap angle of the thread the disk 3.1 results from the sum of the angles α1 + α2.

Due to the heat and wear-resistant design of the invention False twist as well as by reducing the thread tension loss Large rounding radii on the peripheral surfaces of the disks can cause threads Textured with great stability at high production speeds become. The invention is not limited to the disc materials mentioned like elastomer or rubber. Of course they can Disks of the false twister are also made of metal or ceramic.

Reference list

1

Bearing block

2nd

thread

3rd

Disc set, disc

4th

wave

5

Disc set, disc

6

Disc set, disc

7

Thread guide

8th

Leading edge

9

Middle plane

10th

Outlet edge

11

Circumferential surface

Claims (6)

1. False twist device for a synthetic multifilament yarn for use in false twist texturing machines, which comprises at least three sets of disks that are each mounted on an axle for rotation in the same direction, the axles being arranged in the comers of an equilateral polygon, and the disks overlapping in the center of the polygon, so that they form in the center of the polygon a helically winding yarn path with their circumferential surfaces, characterized in that the circumferential surface of the disks is the surface of the zone of a sphere or a torus with a radius (r) in the radial section of the sphere and the torus respectively of a magnitude of at least 35 times the diameter (d_F) of the twisted yarn.
2. False twist device according to claim 1, characterized in that in the case of a textured yarn with a denier > 170 dtex the circumferential surface radius (r) is greater than 35 times the diameter (d_F) of the twisted yarn.
3. False twist device according to claim 1, characterized in that in the case of a textured yarn with a denier < 170 dtex the circumferential surface radius (r) is greater than 40 times the diameter (d_F) of the twisted yarn.
4. False twist device according to one of the foregoing claims, characterized in that the circumferential surface radius (r) is formed in relationship to the disk height (h) such that the center (M) of the circumferential surface radius lies outside the center plane of the disk, preferably between the inlet edge and the center plane of the disk.
5. False twist device according to one of the claims 1 to 4, characterized in that the disks consist at least in the region of the circumferential surface of a heat-resistant elastomer with a resistance to heat greater than 100 °C.
6. False twist device according to claim 5 or as defined in the preamble of claim 1, characterized in that the disks consist of a heat-resistant rubber, in particular hydrogen-saturated nitrile rubber (hydrated nitrile-butadiene rubber (HNBR)).

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