EP0019562B1 - Apparatus for imparting a false-twist by friction to at least one running yarn - Google Patents

Description

The present invention relates to an improved device for communicating a false torsion by friction to at least one moving wire.

The technique of communicating a false twist by friction to a wire has been known for a very long time. This technique consists, in general, of putting the moving wire in contact with a mobile surface moving transversely relative to the path of said wire, so that the latter is twisted upstream and regains its initial twist downstream .

This technique, for which many applications have been envisaged, is mainly used to date for texturing chemical yarns, that is to say for imparting voluminosity and elasticity to them, thanks to a heat treatment followed by 'A cooling of the wire upstream of the false twist member.

Various other applications of false twist have also been envisaged, in particular for producing fancy yarns, yarns having an alternating twist along their length, self-twisted yarns.

Thus, it has been proposed to produce wires with alternating torsion, that is to say comprising successive zones of direction S and direction Z along their length, by using a false twist pin and by varying the length of torsional rise upstream of this spindle, according to a determined frequency (US-A-3,415,048).

As a mobile surface allowing a friction twist to be communicated to a wire, numerous solutions have also been proposed. Those which, to date are used in the field of texturing, use either sockets against the surface of which the thread is in contact (false twist by internal friction), or discs mounted on parallel axes, overlapping each other, the moving wire coming into contact with the external surface of these discs (false twist by external friction).

It has also been proposed in particular in French patents 1,191,361, 1,255,922, and in American patent 2,908,133 to use as organ for communicating the false twist one or more endless belts against the surface of which the wire comes to rub.

As indicated in French patent 1,147,515 (USP 2,943,433), it has also been envisaged to pass the twisting thread between two movable belts, these belts being arranged obliquely to one another , so that the wire is given an impulse in the direction of their movement during their passage between the belts.

However, as indicated in this document, if this false twist device has the advantage of being able to operate at relatively low speeds, it has the disadvantage that it is necessary, where the belts cross, to drive them exactly along parallel planes and keep them at a distance from each other slightly less than the thickness of the wire that you want to provide a false twist.

This involves guiding complex belts from the construction point of view.

Consequently, the aforementioned patent proposes to replace these belts by two hyperboloids driven in rotation, the crossing angles between the axis of these hyperboloids and the generating lines being equal and having an amplitude of 30 ° to 45 °, the wire passing between them along a straight line crossing both of the axes of the hyperboloids at equal angles.

If this solution is attractive, it has the disadvantage of requiring the use of parts of complex shape, difficult to produce and also leads, as in the case of the belt device, to a relatively bulky assembly because the two organs between which the wire passes are arranged one above the other.

Furthermore, the contact surface of the two hyperboloids being a straight line, it is practically impossible to hold the wire along this straight line, which therefore results in a variable action of the hyperboloids.

Finally, with regard to the superimposed crossed belts devices, it has been found that in normal operation, they tend to move laterally on their guide rollers, which disrupts their operation.

However, we have found and this is what is the subject of the present invention, an improved device for communicating a false torsion by friction to a moving wire by means of endless belts, which has the advantages of this type proposed previously, and which, moreover, overcomes the disadvantages, in particular by the fact that it has a reduced bulk, makes it possible to ensure mutual contact between the two belts in a much more precise manner.

In general, the invention relates to a device making it possible to communicate a false torsion by friction to a moving wire of the type described in FR-A-1 076 599 and 2317391 comprising two endless belts, inclined one by relative to each other, mounted on two pairs of rollers and having two strands in mutual contact, the wire passing between these belts in the area where they are in contact so that, on the one hand, they impart a false twist to it , and on the other hand, tend to deliver it, the device according to the invention being characterized in that the diameters and the positioning of said rollers with respect to each other are such that one of the belts passes to the inside each other.

In known manner, the device according to the invention is associated on the one hand with means making it possible to deliver at least one wire between the two belts, as well as to means making it possible to return the treated wire.

Furthermore, it can be associated with any known means allowing either to thermally treat the wire upstream and / or downstream of said device, for example when it is desired to produce a textured wire, a retracted wire, etc., or to vary the wire flow rate and / or the length of the twist rise upstream of said device, when it is desired to obtain a wire having an alternating twist along its length.

Of course, such means could possibly be combined.

Furthermore, it can be used both for treating continuous filament yarns and fiber yarns, or even wicks alone or in combination with other textile elements.

If it is sufficient that at least one of the strands of the internal belt is in contact with one of the strands of the external belt, the two belts can however be mounted on identical guide and drive rollers, so that the two strands are in mutual contact.

In addition, by varying the diameter of the guide rollers, it is possible to vary the contact pressure between the two belts, and consequently to modify the torsion communicated by the latter. It is also possible to provide means making it possible to orient the rollers axially with respect to one another in order to center each belt correctly on said rollers. Furthermore, if the guide rollers can have a cylindrical section, they can possibly be curved.

Likewise, the guide rollers are preferably arranged in the same plane, but it could be envisaged to offset them relative to each other, so that the strands in contact with the two belts are wrapped mutually.

In addition, the introduction of the wire or wires between the belts can be done either in the same plane as their contact plane, or possibly, by having a different angle at the inlet and at the outlet of said belts.

Finally, the device according to the invention is perfectly suitable, in a variant, for obtaining self-twisted wires, said device then being in this case associated, on the one hand, with guides making it possible to bring at least two parallel wires between the contact surfaces of the two belts, and on the other hand, downstream, to a guide making it possible to join the two wires thus treated.

Of course, in this case, means are associated with the belts so that they can communicate to at least one of the wires an alternating twist along its length, these means possibly being of the type described in US-A patent. 3415048, that is to say that they make it possible to vary the length of the twist rise communicated by the spindle according to the invention.

Finally, the two belts will form an angle between them as a function of the twist that you want to communicate with the wire. Advantageously, this angle which is defined by the angle between the two straight lines defining the direction of movement of the belts will preferably be greater than 90 °. It has been found that an angle close to 130 ° is perfectly suitable when it is desired to produce, using the device according to the invention, alternately twisted threads joined downstream of the belts by self-twisting, while an angle close to 150 ° is particularly suitable for communicating a false twist to the wire.

• la figure 1 illustre schématiquement en perspective un dispositif conforme à l'invention dans son application à la texturation d'un fil par fausse torsion,
• la figure 2 est une vue de dessus du dispositif selon la figure 1,
• la figure 3 est une vue schématique de dessus montrant l'application de ce dispositif pour l'obtention de fils autotordus,
• la figure 4 illustre schématiquement en vue de côté le montage d'une courroie sur ses deux galets de guidage, ainsi que des moyens permettant de tendre ladite courroie.

The invention and the advantages which it provides will however be better understood thanks to the following description and examples given, by way of indication but not limitation, and which are illustrated by the appended diagrams in which:

• FIG. 1 schematically illustrates in perspective a device according to the invention in its application to the texturing of a thread by false twist,
• FIG. 2 is a top view of the device according to FIG. 1,
• FIG. 3 is a schematic top view showing the application of this device for obtaining self-twisted yarns,
• Figure 4 schematically illustrates in side view the mounting of a belt on its two guide rollers, as well as means for tensioning said belt.

As can be seen in Figure 1, the device according to the invention. Consists essentially of two endless belts 1, 2, the upper strands 3, 4 are in mutual contact and are inclined with respect to the other. In this case, these belts form an angle of 130 ° between them. According to the invention, these belts are mounted on drive and guide rollers 5, 6, 7 and 8, positioned relative to each other, so that one of the belts (belt 2) passes to inside the other (strap 3). The drive and guide rollers 5, 6, 7 and 8 are rotated by means not shown and are arranged in a conventional manner on a support housing integral with the frame.

In the example illustrated in FIG. 1, the tension of the two belts is obtained by subjecting one of the rollers (rollers 5 and 7) supporting each of the belts, to the action of springs 21, 25. These springs have a point fixed 22, 26 and act on arms 20, 24 mounted at the end of articulation axes 23, 27. These axes can be mounted themselves so as to be able to adjust their orientation in a plane parallel to the axis guide rollers 5, 6, 7, 8 in order to have correct positioning of the belts on said rollers.

In the variant illustrated in FIG. 4, the tension of the belt 1 or 2 is obtained by providing between the two rollers 5 or 7, and 6 or 8, a connection assembly produced in two parts and subjected to the action of a spring 30 exerting pressure on the rollers by means of a sliding part 31. Of course, this Figure 4 illustrates the principle of realization of such a device but, in reality, it is necessary that the assemblies for adjusting the tension of the belts are made in such a way that the latter can pass one inside the 'other. For example, it suffices to make the two tensioning assemblies for each belt so that they have a thickness less than half the spacing between the belts so that they can be arranged one above the other.

Thanks to these embodiments, it is possible, by varying the tension of the belts, to adjust the twist which it is desired to impart to the wire.

The wire 9 coming from a power source not shown is delivered, by any appropriate means, such as a deliverer 10, between these two belts to then be returned or undergo a conventional complementary treatment.

In the embodiment illustrated in FIG. 1, the device is applied to the texturing of a thread 9, and therefore comprises, between the deliverer 10 which serves as a torsion blocking member, a heat treatment oven 11 as well that a cooling zone 12. The wire receives during its passage between the belts 1 and 2, a twist which goes up in the oven and at its exit, finds its initial twist.

As illustrated in FIG. 3, such a device can also be used to communicate an alternating twist to two wires 16, 17 in movement, these two wires being joined together by autotorsion at the output of the device. In this case, upstream and downstream of the belts, in the direction of passage of the wires, there are guides 13, 14 and 18, 19. The guides 13, 14 and 18, 19 make it possible to hold the two wires 16, 17 to be treated in parallel during the passage between the two belts 1 and 2, the guide 15 making it possible to collect them at the outlet of the device.

In the embodiment illustrated in this figure, the alternating torsion is communicated to the wire in a conventional manner, either by varying the speed of delivery of the wires, or, preferably, by varying the length of the torsional ascent upstream of the device. of false twist.

Example 1

Using a device according to the invention consisting of two endless belts 1 and 2, having a length of 28 cm, and mounted on rollers 5, 6, 7 and 8, having a diameter of 2.5 cm. The width of the straps is 1.5 cm.

These belts are driven at a speed of 550 meters per minute and the two strands of the belt 1 are in contact with those of the belt 3, the angle formed between the two belts being 150 °.

On this device, a polyester thread of 72 decitex / 34 strands is delivered, at a speed of 400 meters per minute.

The twist communicated to the upstream wire and which goes up to the deliverer 10 is of the order of 2,400 turns per meter.

A textured yarn is obtained in this way having characteristics comparable to textured yarns by means of pins with internal friction and which in certain cases can be considered to be improved by the fact that the belts not only impart a twist to the yarn but also promote its progression.

Example 2

The same false twist device is used as in FIG. 1, but upstream thereof, we thus have, as shown in FIG. 3, two guides 13, 14 upstream, and two guides 18, 19 in downstream, which makes it possible to bring between the two faces in contact with the belts, two spaced wires 16 and 17.

In this example, the spacing between the two wires is set to 10 millimeters.

Furthermore, a guide 15 provided at the outlet of the two belts and means not shown make it possible to vary the rise in torsion upstream of the device so that for 0.65 seconds, this rise takes place over a distance of 27 centimeters. and that, for 0.65 seconds, it takes place over a distance of 5 centimeters.

In this way, two threads 16, 17 are delivered, each consisting of a core formed by a polyester thread textured by false twist of 167 decitex, 33 strands, covered with wool of 20 microns, the total title of each elementary thread being 250 decitex.

The two wires are delivered at a speed of 205 meters per minute.

The two belts rotate at the same speed as in example 1.

At the output of the device, that is to say of the guide 15, there is obtained a wire assembled by autotorsion of the two wires 16 and 17, this assembled wire having along its length an alternation of zones twisted at about 50 turns in direction Z and at 50 turns, S direction.

The foregoing examples clearly show the advantages provided by the invention and in particular the great flexibility of the device.

Furthermore, it has been found that during long-term operation, compared with the prior belt devices, in which the two belts were superposed relative to each other, very good lateral stability of the belts and as a result a greater regularity of the yarn produced.

Of course, such a device is not limited to the exemplary embodiments given above, but also covers all the variants thereof. Thus, if in the illustrated examples given in the present application, the invention has been described for a device in which the belts are of rectangular section, belts having sections of any other shape could be used, for example belts of circular section, or even belts formed by a plurality of elementary belts placed side by side.

Claims (10)

1. Device permetting to transmit a false-twist by friction to a moving yarn involving two endless belts (1-2), set aslant one in respect with the other, fitted on two pairs of rollers (5-6) and (7-8), and having two strands in mutual contact, the yarn (9) passing between these belts in the zone where they are in contact, in such way that, in one hand, they transmit the false-twist to the yarn and, on the other hand, have tendency to deliver it, characterized by the fact that diameters and position of the two pairs of rollers ones with respect to the others are such that one of the belts (2) passes inside the other (1).

2. Device according to claim 1, characterized by the fact on one hand, it is associated to means (10), permitting to deliver at least one yarn between the two belts (1, 2), and on the other hand, to means permitting to take-up the processed yarn.

3. Device according to one of the claims 1 and 2, characterized by the fact it is associated to thermal treatment means (11) of the yarn (9).

4. Device according to one of the claims 1 and 2, characterized by the fact it is associated to means permitting to vary the yarn output and/or the twist insertion length upstream in such manner that the produced yarn presents an alternate twist along its length.

5. Device according to one of the claims 1 to 4, characterized by the fact that both belts (1-2) are fitted on identical guide and drive rolls (5-6) and (7-8), in such way that both strands of both belts are in mutual contact.

6. Device according to one of the claims 1 to 5, characterized by the fact that the introduction of the yarn or yarns between the belts is realized in the same plane as their plane of contact.

7. Device according to one of the claims 1 to 5, characterized by the fact that the introduction of the yarn or yarns between the belts is realized according to a different angle at the entry and at the exit of the aforesaid belts.

8. Device according to one of the claims 1 to 6, characterized by the fact that it is associated, one one hand, to guides (13-14-18-19) permitting to lead at least two parallel yarns (16-17) between the surfaces in contact of the belts (1)-(2) and one the other hand, downstream with a guide (15) permitting to assemble by autotwist both yarns processed in this manner.

9. Device according to one of the claims 1 to 8, characterized by the fact that the angle formed by the straight lines defining the directions of both belts is different of 90° and is advantageously comprised between 130 and 150°.

10. Device according to one of the claims 1 to 9, characterized by the fact that the belts are fitted on rollers associated to means (30-31) allowing to adjust their tension.

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