EP0126659A1 - Method and device for manufacturing a double yarn - Google Patents

Abstract

1. A spinning process of a fibre yarn in which at least two roves of fibre are stretched between the drafting points of the said roves and pairs of stretching rollers ; a continuous filament is introduced into each rove upstream of the pairs of stretching rollers ; the strands formed by each rove of fibres and each filament are twisted by twisting means, in particular by rubbing (7), and in this way, sufficient cohesion is given to the strands formed at a particular point ; and the stands are gathered into a converging point (12) ; the tension of the strands is adjusted ; the strands are wound ; the yarn formed by the strands is retwisted on a twisting frame after winding, characterized by the fact that each filament is cut upstream of the stretching rollers and each filament cut is eliminated.

Description

The subject of the present invention is a method and a device for spinning fiber yarns, optionally comprising at least one core.

Yarn production can be performed on many spinning systems. We know, in particular, ring-cursor systems, self-twisting systems, those with free ends, wrapping etc ...

A special case of thread is found in core threads, in which a core thread is wrapped in a sheath of staple fibers. Processes for obtaining core yarns are described in particular in the patents of the United States of America Nos. 1373880, 2024156, 2210884, 2313058, 2504523, 2526523, 3017740 and 3038295.

The production of core yarns can be carried out on numerous spinning systems commonly used for the manufacture of yarns from staple fibers. However, and in particular with the ring-cursor system, the threads with spun cores generally have the disadvantage of being limited in the speed of production to that of the machines employed and therefore to the twisting system used.

Self-twisted core yarns are known from United States Patent No. 4033102. An original embodiment of self-twisted core yarns is described in French patents No. 7918173 and 7913995. The advantage of this process is to require only unidirectional movements at constant speed. On the other hand, its great drawback is that it imposes sudden and significant variations in torsion and therefore in tension which limit their efficiency at the level of production speed, and increase the risks of slipping of the covering fibers with respect to blade.

French patent n ° 8111642 avoids these drawbacks and allows a high production speed without slipping of the covering fibers relative to the core and achieves after twisting a unidirectional twist of the ply. Its great drawback is that it requires the use of one or more continuous filaments acting as a carrier for the covering fibers, which can be a drawback in the final product.

The object of the present invention is to enable fiber yarns with or without cores to be obtained with an extremely high production speed, obtained by consolidating the resistance of the fiber yarn, preferably when it has to withstand forces. .

This object is achieved by a process for spinning fiber yarns, a process in which at least one strand of fibers is stretched between points of supply of these strands and pairs of stretching cylinders, upstream of which a continuous filament is introduced. and in accordance with the invention, the strands formed by each strand of fibers and each continuous filament are twisted by a torsion member preferably with friction, by making them converge at the same point situated upstream or downstream of the torsion. The thread thus formed is passed through a pair of delivery cylinders placed after the torsion member, the thread is spooled on an appropriate support and the thread thus formed is twisted possibly by the strands on a twisting loom.

This process is such that the thread is given at a precise determined point, sufficient cohesion to allow twisting. Thus, there is no break in the fiber yarn. Preferably, the cohesion of the wire is given between the point of twisting and between the point of unwinding of the wire:

The wire thus formed according to the invention is twisted on a conventional twisted loom, for example with a slider ring or with double twist or with a double step to give the final twist.

According to another embodiment, the cohesion is given to the yarn by sizing the fibers, namely by adding a cohesive product, to the fibers for example, before drawing the strands of fibers, in particular at the level of the preparation of the strands. , or more preferably after twisting the strands and before winding them.

According to the invention, the wire which is wound is such that there is no assembly twist which is avoided by adjusting the tension. If this assembly torsion exists, due to irregularities in the functioning of the torsion member linked to irregularities in the mass of the wire, it is a random twist, or alternating twist or non-regular self-twist. It is therefore neither regular in steps nor in intensity. The invention makes it possible to avoid such an unwanted assembly twist of the wound wire.

To make a coreless wire, the continuous filament or filaments are cut before winding. Preferably, the continuous filament or filaments are cut upstream of the stretching cylinders. This constitutes a mode of launching the manufacture which is in no way limiting and one can provide for other ways of proceeding.

According to a particular embodiment of the invention, at least two wicks of fibers are stretched separately between supply points and pairs of stretching cylinders, the continuous wires are supplied, they are introduced into said strands upstream of the different stretching cylinders and the strands formed at the same point of a torsion member are made to converge. The strands formed are passed through a pair of delivery cylinders and the continuous filaments are cut, upstream of the stretching cylinders, before the remaining assembly is wound. The assembly formed by the fibers is then put on a twisting loom where a resistance of the wire is ensured between the point of unwinding of the wire on the spool and the point of taking torsion.

• - des moyens de réalisation d'au moins deux brins de fibres,
• - des moyens d'alimentation d'au moins un filament continu dans chaque brin,
• - des moyens de fausse torsion des brins, de préférence par friction,
• - des moyens de réglage de la tension des brins, de préférence situés en aval des moyens de torsion, éventuellement des moyens d'élimination du filament continu,
• - des moyens de bobinage,
• - des moyens de retordage du filé,
• - des moyens conférant une cohésion suffisante pour permettre de retordage.

This object is also achieved by a device for spinning fiber yarns optionally comprising at least one continuous filament, comprising:

• means for producing at least two strands of fibers,
• means for feeding at least one continuous filament in each strand,
• means for false twisting of the strands, preferably by friction,
• means for adjusting the tension of the strands, preferably located downstream of the torsion means, possibly means for removing the continuous filament,
• - winding means,
• - means for twisting the yarn,
• - Means giving sufficient cohesion to allow twisting.

Preferably, the cohesion means are placed between the point of unwinding the wire on the spool and the torsion point during twisting.

According to the invention, the wire which is wound has a very particular structure. Indeed, it is formed of at least two strands placed side by side having a low residual twist, possibly alternating, very low, sufficient to ensure cohesion of the covering fibers on the filament and insufficient to cause the assembly of the two strands by regular and constant self-twisting.

Finally, the yarn after twisting is such that the fibers are all substantially parallel to each other in the axis of each strand with a variation equal to the very small residual twist existing in the yarn before twisting, but as we know dissociate the two strands by untwisting.

It is indeed a two strand wire.

• - la figure 1 est une vue schématique, en perspective d'un dispositif de filage avant l'arrêt du filament continu dans le cas où lepoint de convergence est en amont du tordeur.
• - la figure 2 est une vue schématique en perspective d'un dispositif permettant d'obtenir un fil double avant la montée en torsion et après la coupe du filament, dans le cas où le point de convergence est en aval du tordeur.
• - La figure 3 est une vue en perspective d'un dispositif, permettant d'obtenir une résistance du filé entre le point de dévidage du fil sur la bobine et le point de prise de torsion d'un métier à retordre.
• - La figure 4 est une vue en coupe dudit dispositif de la figure 3, monté sur la coronelle de dévidage d'une retordeuse double-torsion.
• - La figure 5 est une vue en perspective d'une variante du dispositif de la figure 3.
• - La figure 6 est une vue en perspective d'une autre variante du dispositif de la figure 3.
• - La figure 7 est une vue schématique du dispositif de la figure 5, monté sur un métier à retordre à anneau cursseur.
• - La figure 8A est une vue du fil après retordage selon l'invention.
• - La figure 8B est une vue d'un fil de la technique antérieure.

The invention and the advantages which it brings will however be better understood thanks to the examples of implementation, given below by way of illustration, but not limitation and which are illustrated by the appended figures in which:

• - Figure 1 is a schematic view in perspective of a spinning device before stopping the continuous filament in the case where the point of convergence is upstream of the twister.
• - Figure 2 is a schematic perspective view of a device for obtaining a double wire before the rise in torsion and after the cutting of the filament, in the case where the point of convergence is downstream of the twister.
• - Figure 3 is a perspective view of a device, for obtaining a resistance of the yarn between the wire unwinding point on the spool and the point of torsion taking of a twisting loom.
• - Figure 4 is a sectional view of said device of Figure 3, mounted on the coring reel of a double-twist twister.
• - Figure 5 is a perspective view of a variant of the device of Figure 3.
• - Figure 6 is a perspective view of another variant of the device of Figure 3.
• - Figure 7 is a schematic view of the device of Figure 5, mounted on a twisting loom with slider ring.
• - Figure 8A is a view of the thread after twisting according to the invention.
• - Figure 8B is a view of a thread of the prior art.

According to the invention, a spinning process is carried out by stretching a wick of fibers 5a between a supply point 2a and a pair of stretching cylinders 4a. The stretching system further comprises a pair of stretch sleeves 3a. in parallel, a strand of fibers 5b is stretched separately by a drawing system comprising a supply point, namely a pair of food rolls 2b, a pair of drawing sleeves 3b and a pair of drawing rolls 4b.

Upstream of the stretching cylinders (4a, 4b) a continuous filament (6a, 6b) is introduced. Two strands are therefore formed, each consisting of a wick of fibers and a filament. The strands thus formed are twisted together by a wringer 7 and are guided by two guides 8 and 9. The two strands then pass through a pair of cylinders 10 before being aspirated by a vacuum cleaner 13 before removing the continuous filaments for example by cutting, using a pair of manual scissors, upstream of the stretching cylinders.

The continuous filaments thus cut are therefore brought by the vacuum cleaner 13 to the waste.

FIG. 2 shows the spinning device after cutting the filaments, when the fiber yarn is wound on a cylinder 11.

It is important to have a sufficient number of fibers in 'section, in relation to the cohesion of the fibers, the cleanliness of the wick and the tension between the stretchers 4 and the delivery cylinders 10.

Regarding the cohesion between the fibers, it may be advantageous to add to the fibers, during the preparation of the wicks, by sizing increasing this cohesion between the fibers. For example, a paraffinic sizing agent or a sizing agent containing colloidal silica. This also has the effect of facilitating twisting.

In the case where the point of cover is upstream of the torsion member.

It is also important to adjust the tension between the stretchers 4 and the delivery cylinders 10, so as to have a suitable distance h between the stretchers 4 and the point of convergence 12 of the wires, in relation to the given twist and the speed of scrolling. Indeed, a twist exists in each of the single strands, between the point of convergence 12 of the strands and the point where the strand is lastly gripped by the stretchers 4, but this twist is not incorporated in the resulting wire. This twist exists in the strands prior to convergence in an amount of equilibrium which depends on the geometry of the system and the spinning parameters. This state of affairs described above can in practice be modified. Indeed, irregularities occurring randomly in the strands, part of the twist is incorporated into strands in a randomly varying manner. Such a twist is however of low intensity.

If the tension is too low, too little torsion is found in the strand between the stretching cylinders 4 and the point of convergence 12, which results in fiber losses at the outlet of the stretching cylinders 4, following poor attachment. fibers. For example, excellent results have been obtained at a speed of 215 meters per minute with a stretch, between the stretchers 4 and the deliverers 10, equal to 1.53% and a 2 × 25 tex yarn composed of 45% wool 27 microns and 55% 3 denier polyester. Thus, the difference in speed between the stretching cylinders 4 and the delivery cylinders 10 is adjusted as a function of the spinning parameters and the speed of movement. If the tension is too high, the thread is too tight, which leads to a risk of breakage.

In the case where friction torsion members are used which provide both a torsion component and a thread advancement component, it may be advantageous to adjust the thread tension by variation of this advancement component, independently the tension adjustment between the delivery and stretching cylinders. For example when using two endless crossed belts this adjustment is done by varying the angle of the two belts.

When the yarn of fibers is in the twisting stage, its resistance is generally too weak to allow a walk without problems and the yarn breaks. often between the wire feed point on the spool and the torsion point.

However, it has been found that a very slight additional cohesion is sufficient to ensure the unwinding of the wire. Depending on the initial cohesion of the fibers, a simple cohesive sizing may be sufficient. This cohesive product can be added to the fibers, either at the level of the preparation of the wicks itself at the level of the spinning machine, between the twist member of the strands and the winding member.

In cases where this is not enough or when the use of sizing is to be avoided, it has been found that the addition of a few twists, using a false twist device is sufficient to ensure good reeling.

False twist devices are known. They can be rotary or operate by friction. They can be static and a simple winding on a rod can ensure a torsion by rolling upstream of the rod when one pulls on the wire, provided that the angle of the wire with respect to the rod, the diameter of the rod according to that of the wire as well as the pitch of the wire on the rod and the coefficient of friction of the material of the rod, are judiciously chosen.

The example in Figure 3 is a device that achieves these requirements. It consists of a body 14 of light material which supports a rod 15 in the form of a semicircle on the upper part of the body 14.

The use of the device of FIG. 3 will however be better understood thanks to FIG. 4 which represents a section of a double twist twisting spindle in which the coil of wire 16 is placed on the pot 17 where it is centered thanks to the centering device 18.

The wire 19 is unwound in the parade, leaving the reel passes through the eyelet 20 of the wire feeder 21. The wire is then wound on the rod 15 which is supported by the body 14, itself fixed by any means not shown, on the coronelle 21. After having made a certain number of turns the wire enters the body of the extension 22 where it will receive the first twist turn given by the disc torsion (not shown) to then pass between the pot 17 and the anti-balloon 23 where it receives the second turn of twist before being wound on a reel not shown.

In general, in a double twist twisting machine, the thread tension and therefore the number of turns of winding on the torsion disc is adjusted by a spring piston, torsion blocker, not shown, which is in the extender 22.

In the case of using the device, according to the invention, it is necessary either to remove this piston and thus the torsion goes up to the rod 15, or to have a distance between this piston and the rod 15, less than the length of the fibers.

• - nombre de tours d'enroulement du fil 19 sur la tige 15,
• - diamètre de la tige 15,
• - coefficient de frottement du matériau de la tige 15,
• - angle a formé par le fil 19 et la tige 15 au moment où le fil arrive sur la tige.

Using the device, the thread tension is adjusted, by adjusting the following parameters:

• - number of turns of winding of the wire 19 on the rod 15,
• - diameter of the rod 15,
• - coefficient of friction of the material of the rod 15,
• - angle α formed by the wire 19 and the rod 15 when the wire arrives on the rod.

We can vary the rotation of the wire feeder 21 by conventional means, for example, its weight, its coefficient of friction, etc. We can, as with a conventional double twist twisting machine play on the force of the spring blocker torsional, in case it is used.

For example, good results have been obtained with the 2 x 25 tex yarn, described previously on a double twist twist loom with a spindle speed of 11,000 rpm and a twist of 371 rpm, a development of 59 , 2 meters per minute, using the device described in Figure 4 where the wire made 1 turn on a spring steel rod 0.5 mm in diameter, without using a torsion blocker.

Good results have been obtained with a 2 x 33 tex yarn, one strand of which consists of a 300-denier filament made of shiny triacetate, without fiber covering and the other strand, consisting of fibers of 100% matt acrylic 3 deniers, without filament. The whole being twisted to 260 spindle turns at a double twist spindle speed of 10,000 revolutions per minute using the device described in Figure 4 where the wire 19 made 2 turns of winding on the rod 15 which had a diameter 0.25 millimeter, and without using a torsion blocker.

A variant of the device is shown in Figure 5 where the wire is wound on a straight rod.

Depending on the yarns to be twisted, it will be possible to have different angles of the rod relative to the vertical, so as to change the angle of the yarn relative to the rod in order to vary the intensity of false twist.

The examples of device form described are given without limitation. The only imperative is to have a winding of the wire on the rod with an appropriate angle of the wire with respect to the rod. More generally, any device is used which allows a false twist between the unwinding and the taking of torsion, which allows the unwinding of the thread during twisting without it breaking due to its low resistance.

Another variant of the device is shown in Figure 6 where the rod is spiraled into a cone.

In the case where one twists by another twisting technique, for example with a continuous twisting ring, as shown in Figure 7, it will suffice to place a rod 24 between the coil 25 and the deliverers 26 to have a certain angle of the wire with respect to the rod so as to give a false twist sufficient for the unwinding, in order to obtain a distance between the rod and the deliverers less than the length of the fibers. The tension is in this case given by the cursor weight 27.

In the case where one twists by the two-step twisting technique, it will suffice to adapt the device of FIG. 7 to the first twisting assembly step.

Thus, according to the invention, a yarn of fibers is obtained comprising at least two strands, which does not have any discontinuities, such as knots, splices or stops and which allows the production of spools of wire of significant weight, for example weighing at least 1 kg for fine threads, for example around 10 tex and spools of thread of at least 10 kg for coarse threads, for example for threads of around 1000 tex.

Such a wire is shown in Figure 8A. As can be seen, the fibers 28 are substantially much more parallel to each other than the fibers 29 of a thread of the prior art, all other things being equal.

Claims (15)

1. A method of spinning a yarn of fibers possibly comprising a core according to which one stretches at least two wicks of fibers between the feeding points of this wick and pairs of stretching cylinders, a continuous filament is introduced into each wick. upstream of the pairs of stretchers, the strands formed by each wick of fibers and each filament are twisted by a torsion member in particular with friction (7) and they are brought together at the same point of convergence (12), the tension of the strands, the strands are wound, possibly twisting the wire formed from the strands on a twisting loom, after winding, characterized in that sufficient cohesion is given to the strands thus formed at a determined point. 2. Method according to claim 1, characterized in that one gives cohesion to the strands between the point of torsion and unwinding. 3. Method according to any one of claims 1 and 2, characterized in that each filament is cut, in particular upstream of the stretching cylinders. 4. Method according to any one of claims 1 to 3, characterized in that the thread tension is adjusted by variation of the advancement component of the torsion member. 5. Method according to any one of claims 1 to 4, characterized in that the core filaments (6a, 6b) are introduced into the wicks (5a, 5b) of fibers before imparting the twist. 6. Method according to any one of claims 1 to 5, characterized in that one adjusts the tension of the strands before winding by adjusting the speed difference between the delivery cylinders (10) and the stretching cylinders (4). 7. Method according to any one of claims 1 to 6, characterized in that the yarn is twisted after winding on a twisting loom by giving cohesion between fibers using a cohesive product applied to the preparation of wicks or between the torsion member and the coil. 8. Method according to any one of claims 1 to 7, characterized in that the yarn is twisted after winding on a twisting loom by giving false twist to the strands between the point of unwinding the yarn on the spool and the point of torsion. 9. Method according to any one of claims 1 to 8, characterized in that the yarn is twisted after winding on a twisting loom by giving false twist to the strands between the point of unwinding the yarn on the spool and the point of torsion taking by winding the wire on a rod making an angle with the wire, at a place located at a distance from the point of torsion, less than the length of the fibers. 10. Method according to any one of claims 1 to 9, characterized in that one regulates the tension of the wire with the twisting machine by varying the number N of turns of winding of the wire on the rod, the angle formed by the wire and the rod, the diameter of the rod and its coefficient of friction. 11. Device for implementing the method according to any one of claims 1 to 10, for spinning fiber yarns comprising at least two strands, said device comprising: - Means for producing at least two strands consisting of at least one wick of fibers (5a) and at least one continuous filament (6a); - means for removing the continuous filament; - means of false twist (7) by friction of the strands; - means for adjusting (10) the tension of the strands located downstream of the torsion means (7); - winding means (11), - means for twisting the wire formed by the strands; means for increasing the resistance of the wire between the point of unwinding the wire on the spool and the point of taking torsion when twisting the wire. 12. Device according to claim 11, characterized in that the means for producing a strand comprise a pair of feed rollers (2) of a wick of fibers, a pair of drawing sleeve (3) of the wick, a pair of stretching cylinders (4) of the wick, a condenser located between the stretching sleeve (3) and the stretching cylinders (4); the means for frictionally twisting the strands comprise endless moving surfaces; the means for adjusting the tension of the strands comprise delivery cylinders 10, the speed of which is adjusted relative to the speed of the stretching cylinders 4; the means for removing the continuous filament comprise scissors; the twisting means consist of a twisting loom; the means for increasing the resistance of the wire are produced firstly by false twisting by winding the wire around a rod making an angle with the wire and placed between the point of unwinding of the wire on the spool and the point of taking of twisting at a distance from the point of twisting less than the length of the fibers and secondly possibly, by adding a cohesive product to the preparation of the wicks or to the spinning, between the torsion member and the winding. 13. Device according to any one of claims 11 and 12, characterized in that it comprises at least two means for producing strands. 14. Yarn of fibers, comprising at least two strands, manufactured by the method according to any one of claims 1 to 10, characterized in that it consists only of fibers and such that the fibers are all substantially parallel to each other. to the others in the axis of each strand, the strands being placed side by side and having a small residual twist insufficient to cause the assembly of the strands but sufficient to ensure the cohesion of the strands. 15. Yarn of fibers, comprising at least two strands, manufactured by the method according to any one of claims 1 to 10, characterized in that it does not have any discontinuities such as knots, splices or stops and allowing the realization of spools of son of a significant weight, for example at least 1 kg for fine threads, for example around 10 tex and at least 10 kg for coarse threads, for example around 1000 tex.

Images