EP0022421A1 - Method and apparatus for producing a yarn having along its length alternating opposite twist zones - Google Patents

Abstract

The invention relates to a method for obtaining a wire (7) with alternating twist, obtained by intermittently varying the length of the twist rise upstream of a false twist member (5). The method according to the invention is characterized by the fact: - that the variation in the length of the torsional ascent is achieved without braking the wire and is obtained by means of a blocker (8) acting intermittently at a point located most as close as possible to the element communicating the false twist (5). - And that the duration of action of the blocker (8) corresponds substantially to the duration that a point considered of the wire (2) takes to cross the distance D between the delivery member (2) and the false twist member ( 5).

Description

The present invention relates to an improved method for obtaining a wire having, along its length, zones of torsion alternately in opposite directions; it also relates to a device for implementing this method, as well as its application to obtaining self-twisted yarns.

The technique which consists in communicating to a thread, whether it is based on continuous filaments or staple fibers, a twist alternately of direction S and Z has been known for a long time.

The oldest which is used in particular for imparting resistance to a wick of fibers during spinning, consists in subjecting said wick to the action of a friction element, acting transversely with respect to the direction of movement of the wick , alternately from right to left, then from left to right.

It has also been proposed, in particular in United States patent n-2 3 225 533 to subject a multifilament yarn to the action of an air jet directed tangentially with respect to the displacement of the yarn, alternately d 'on one side and on the other of it, so that we obtain successive areas of direction S and Z.

Furthermore, numerous documents describe the use of false twist pins, under special conditions, in order to communicate such alternating twist. If it is well known that the pins of false twist, whether by internal friction, that is to say by contact with the surface of sockets, or by external friction, that is to say by contact with the outer surface of discs, or by any other means, such as for example using belts, allow under normal processing conditions, to obtain a true twist upstream of the spindle, the wire at the outlet of the latter having no torsion, it is possible, for example, by varying the speed of rotation of said spindle, or the speed of passage of the wire, or the length of torsional rise upstream of the spindle, to obtain wires which at the outlet have alternating twists.

Thus, American patent 3,415,048 describes the use of such a false twist spindle making it possible to communicate an alternating twist to a continuous multifilament yarn, the spindle rotating at constant speed and the alternating twist being obtained by varying the length of torsional rise upstream of the spindle by means of a brake acting intermittently in the vicinity of said spindle or whose area of action is displaced.

The methods for communicating alternating twist to a moving wire, however, have a number of disadvantages. First of all, those which use an intermittent action of the twisting member or an inversion of its direction of action do not allow high speeds, and are of a complex mechanical construction.

Furthermore, if in the technique described in USP 3,415,048, it is possible to use a conventional false twist spindle rotating at constant speed, the alternating twist being obtained by varying the length of the ascent of the twist, it is possible to working at significantly higher speeds, this technique still has a number of disadvantages, however. Indeed, in the case where it is desired to treat not a multifilament yarn with continuous filaments, but a yarn of fibers or a wick, the action of the brakes intended to block the rise in torsion can cause the breaking of said yarns or the accumulation of fibers at the brake and, in the case of core wires, a bundle of fibers around this core.

However, we have found, and this is what is the subject of the present invention, an improvement to this process which overcomes the drawbacks thereof and makes it possible to treat both continuous filament yarns and fiber yarns, or even locks, the twist rate in each area of direction S and Z being moreover significantly higher than in the previous methods.

In addition, the method according to the invention is particularly suitable for the production of self-twisted yarns, that is to say yarns produced according to the technique which generally consists in bringing together at least two threads, the at least one has an alternating twist, so that they wrap around each other. Preferably, the two wires are alternately twisted so that they wind around one another, the zones of twist in the same direction being either in phase or slightly out of phase with respect to the 'other. Such a technique is described in French patent 1,405,219 (USP 3,225,533), and will not be described in detail.

In this particular application, the invention makes it possible to obtain self-twisted yarns which, compared with the previous yarns, have many advantages such as, in particular, a higher production speed, possibilities for easily varying the length of the torsion reversal cycle, to simply adjust the phase difference between the two alternately twisted wires intended to form the self-twisted wire.

• - à délivrer positivement un fil élémentaire,
• - à communiquer à ce fil une fausse torsion au moyen d'une broche située à une distance éloignée des organes délivreurs de fil,
• - à faire varier, de façon intermittente, la longueur de remontée de torsion en amont de l'organe de fausse torsion, de telle sorte que, à la sortie de cet organe, le fil élémentaire présente une torsion alternée sur sa longueur,
• - à renvider le fil ainsi formé, et il se caractérise par le fait que :
• - la variation de la longueur de remontée de torsion :
  • . est réalisée sans freinage du fil,
  • . est obtenue au moyen d'un bloqueur agissant de façon intermittente en un point situé le plus- près possible de l'élément communiquant la fausse torsion,
• - la durée d'action du bloqueur correspond sensiblement à la durée que met un point considéré du fil pour franchir la distance comprise entre l'organe délivreur et l'organe de fausse torsion.

In general, the invention therefore relates to a process for obtaining a wire which has, along its length, zones of torsion alternately in directions S and Z which consists, in known manner:

• - to positively deliver an elementary thread,
• - to communicate a false twist to this wire by means of a pin located at a distance distant from the wire-delivering members,
• to vary, intermittently, the length of the twist rise upstream of the false twist member, so that, at the outlet of this member, the elementary wire has an alternating twist along its length,
• - rewinding the wire thus formed, and it is characterized by the fact that:
• - the variation in the length of the twist rise:
  • . is performed without braking the wire,
  • . is obtained by means of a blocker acting intermittently at a point located as close as possible to the element communicating the false twist,
• - The duration of action of the blocker corresponds substantially to the duration that a point considered of the wire takes to cross the distance between the delivery member and the false twist member.

Preferably, the alternating torsion communicated to the wire is stabilized downstream of the false twist member, and this, in an area located in the vicinity of the exit of the wire from said member.

Thanks to the particular conditions of the process according to the invention, it has been found that an alternating twist yarn is obtained, which, compared with previously produced yarns, has a better alternating twist yield on the produced yarn, for a value determined by distorted twist communicated to the wire.

Such a method makes it possible to produce unitary threads having an alternating twist along their length, these threads being able to be based on continuous filaments or fibers and possibly being associated with a core when they are obtained.

In this case, the stabilization of the alternating torsion communicated to the wire is obtained using conventional means, such as an interlacing nozzle, a sizing treatment, arranged as close as possible to the outlet of the member. communicating the wrong twist.

• - que l'on délivre positivement au moins deux fils élémentaires maintenus séparés,
• - que l'on communique à au moins l'un de ces fils une fausse torsion,
• - que l'on fait varier la longueur de remontée de torsion en amont de l'organe de fausse torsion sur au moins l'un des fils, de telle sorte qu'à la sortie de cet organe le ou les fils ainsi traités présentent une torsion alternée sur leur longueur,
• - et enfin, que l'on juxtapose les deux fils de manière à provoquer leur autotordage.

The method according to the invention is however particularly well suited for the production of self-twisted yarns. In this particular application, the method according to the invention is characterized, in addition to the above points, by the fact:

• - positively delivering at least two elementary wires kept separate,
• - that a false twist is communicated to at least one of these wires,
• - That the length of the twist rise upstream of the false twist member is varied on at least one of the wires, so that at the outlet of this member the son or wires thus treated have a alternate twist along their length,
• - And finally, that we juxtapose the two wires so as to cause their self-twisting.

In this case, the alternating torsion stabilization operation presented by the produced yarn is obtained not by an additional treatment (interlacing, gluing) carried out at the exit from the false twist member but corresponds to the juxtaposition operation of the two wires in order to cause their self-twisting, this juxtaposition also being carried out in the immediate vicinity of the zone of exit of the wire from the false twist member, or even even inside this member when the latter is a friction pin internal.

In this application, if only one of the wires can receive an alternating torsion in accordance with the invention, it is however advantageous to communicate such an alternating torsion to the two elementary wires, this torsion preferably being communicated by means of a single false member. torsion In this case, of course, it is necessary to keep the two separate wires in the false twist member.

• - la figure 1 est une vue schématique en perspective d'une installation permettant l'obtention d'un fil à torsion alternée unitaire,
• - la figure 2 est également une vue schématique en perspective d'une installation permettant l'obtention d'un fil autotordu, obtenu à partir de deux fils unitaires à torsion alternée réalisés conformément à l'invention,
• - la figure 3 est une vue en perspective agrandie d'un organe de fausse torsion et d'un élément permettant de faire varier la longueur de remontée de torsion en amont de cet organe,
• - la figure 4 est une vue de détail en perspective d'un dispositif permettant de faire varier la longueur de remontée de torsion en amont de la broche, cette dernière n'étant pas représentée par mesure de simplification,
• - la figure 5 illustre schématiquement en vue de côté une variante concernant la position de la broche par rapport à l'élément permettant de faire varier la remontée de torsion.

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:

• FIG. 1 is a schematic perspective view of an installation making it possible to obtain a unitary alternating twist wire,
• - Figure 2 is also a schematic perspective view of an installation for obtaining a self-twisted yarn, obtained from two unitary twisted yarns produced in accordance with the invention,
• FIG. 3 is an enlarged perspective view of a false torsion member and of an element making it possible to vary the length of the torsional ascent upstream of this member,
• FIG. 4 is a detailed perspective view of a device making it possible to vary the length of the torsional ascent upstream of the spindle, the latter not being shown for the sake of simplification,
• - Figure 5 schematically illustrates a side view of a variant concerning the position of the spindle relative to the element for varying the rise in torsion.

In the following description, the invention will be described more particularly for obtaining an alternating twist yarn or a self-twisted yarn from wicks of fibers, and this, directly during the drawing operation. of said wick, a core which may or may not be incorporated into the wick before it leaves the drawing zone.

It is obvious that this is not limiting and that the invention can be applied to continuous filaments, possibly directly during their manufacture, for example following spinning, extrusion and drawing operations.

FIG. 1 shows an example of implementation of the invention for obtaining a unitary wire with alternating twist.

• - un support 1 de stockage de la matière 2 à traiter, dans le cas présent une mèche de fibres,
• - un délivreur positif 3 dudit fil élémentaire constitué par la dernière paire de cylindres d'appel d'un train d'étirage conventionnel 4 à double manchon,
• - d'une broche de fausse torsion 5 entraînée en rotation à vitesse constante,
• - d'élément de renvidage 6 du fil formé 7.

The installation used comprises in order:

• a support 1 for storing the material 2 to be treated, in this case a wick of fibers,
• a positive deliverer 3 of said elementary wire constituted by the last pair of call cylinders of a conventional drawing train 4 with double sleeve,
• a false twist spindle 5 driven in rotation at constant speed,
• - winding element 6 of the formed wire 7.

In this embodiment, the false twist spindle 5 is an internal friction spindle, but it is obvious that any other type of spindles could be used, for example an external friction spindle, one or more friction belts ...

According to the invention, the deliverer 3 is disposed at a relatively large distance from the false-twist member. 5.

Furthermore, in the immediate vicinity of the entry of the false twist spindle 5, an element 8 is arranged which makes it possible to vary the length of the twist rise without braking the wire. This element, designated by the expression "blocker" in the present description, is constituted in one embodiment by a positive deliverer which acts intermittently on the wire so that for a duration substantially equal to the time taken by a stitch considered wire to cross the distance D between the delivery member 3 and the false torsion member 5, the torsion communicated by the spindle 5 is stopped by the blocker 8 while, when the blocker does not act, the torsion goes back freely to the deliverer 3.

If in the following description, the invention will be described more particularly with the use of a blocker acting on the wire intermittently, for equal durations of blocking the rise in torsion and non-blocking, it is obvious that the one could, without departing from the scope of the invention, have different durations for these two actions.

In the embodiment illustrated by the appended figures, this blocker is constituted by a positive deliverer which comprises an upper cylinder 9 having a smooth surface, produced for example from a material sold under the brand "Vulkolan", this cylinder 9 being supported on a steel cylinder 10 which has, on a part of its periphery, grooves. The wire passing between these two cylinders, when the grooved zone faces the cylinder 9 it is not delivered and the twist can go back up to the deliverer 3. On the other hand, in full areas, the wire is positively driven and the twist cannot go back up. It is therefore possible to thus vary the length of the torsional rise. The length of the solid parts and of the grooves of this cylinder 10 must be such that the wire is delivered positively for a duration substantially equivalent to that which a point considered of said wire takes to cross the distance between the element 3 delivering basic wire, and the false torsion member 5.

In such an embodiment, the diameter of the cylinder 10 is such that the perimeter of the said cylinder is substantially equal to twice the distance D between the spindle 5 and the deliverer 3. In the appended figures, the proportions between the diameter of the cylinder 10 and distance D were not respected in order to make them clearer.

The cylinder 10 has a notch on half of its periphery and is driven at a peripheral speed substantially equal to the speed of movement of the wire 2. In this way, it is therefore possible to block the rise in torsion alternately between a point located on the as close as possible to the false twist member 5 and a relatively distant point constituted by the deliverer 3, and this, for a duration substantially equal to the time taken by a point of the thread to cross the space D.

It has been found that by operating in this way, the alternating twist yarn produced at the outlet of the spindle had, compared to the previous yarns, a much higher alternating twist level for a given false twist.

It is obvious that the invention is not limited to the only type of torsion blocker described above, but that it can be used with any equivalent device. Thus, one could for example use as a blocking member for delivering the wire, a deliverer consisting of two positively driven rollers, one of these rollers being mounted on a support associated with means allowing to bring it intermittently in contact with the second.

Furthermore, in the case of obtaining a single wire with alternating twist, the installation comprises, immediately at the outlet of the false twist spindle 5, a conventional member 21 making it possible to stabilize the twist, this member being able to be consisting, for example, of a compressed air interlacing nozzle, or a wire bonding system.

Such an installation can also be used to produce yarns of fibers having an internal core. In this case, the core is preferably brought upstream of the stretching cylinders 3, this core 22 being shown in dotted lines in FIG. 1, either above or below the wick 2, but as close as possible to the part central of it.

Furthermore, in order to eliminate the fluff and down that may occur, suction means can be associated with the installation, these means being constituted for example by conventional pipettes preferably arranged in the vicinity of the outlet of the dispenser. 3.

Finally, in particular when a core is to be incorporated into the wick, the installation may also include a false-twist member 23, such as for example a pneumatic nozzle which facilitates the winding of the fibers around the core and the centering of the latter, this false-twist member being disposed near the outlet of the deliverer 3.

In addition, condensers can be arranged upstream of the drawing train 3 in order also to promote the centering of the core in the wick.

FIGS. 2, 3 and 4 illustrate an installation produced in accordance with the invention, making it possible to simultaneously treat two wires which are then, before winding, joined together by autotorsion.

Compared to the self-twisting described above, and which is illustrated by FIG. 1, the only differences reside in the fact that it comprises a second feeding system 1, 3, 4 of wire 2, and that, the intermittent blocker 8 is constituted by a deliverer, of the same type than that described above, but which makes it possible to act simultaneously on the two wires.

Such a delivery device, a particular embodiment of which is described in more detail in FIG. 4, comprises as before, a smooth cylinder 9, for example made of Vulkolan, and a steel cylinder 10 having grooves on its periphery. This cylinder 10 is advantageously made in two juxtaposed parts 31, 32, each having in their central zones, grooves 33, 34. The perimeter of the cylinder 10 and the length of the grooves 33, and 34, will be determined in the same way as previously, but it is possible, in such an embodiment, to phase-shift the alternating torsion zones produced on the two elementary wires 2 in a simple manner, by shifting these two grooves 33, 34, with respect to one another.

Of course, guides, for example ceramic fingers 35 and 36, are provided upstream of the intermittent blocker 8 to keep the two wires parallel.

In this embodiment, the stabilization of the alternating torsion communicated to the two wires is obtained by the self-twisting of these two elements one on the other.

When using, as illustrated in the appended diagrams, as an element of false torsion, an internal friction spindle, it is advantageous to provide a separator guide 11 conforming to the surface of this spindle in the friction zone, so as to keep the two wires separated up to the point where the self-twisting is carried out.

Furthermore, as shown in more detail in Figure 3, when using an internal friction pin, it will advantageously have a concave external surface allowing it to marry the periphery of the cylinder 10 and consequently of bringing the edge of this spindle as close as possible to the area of action of the intermittent deliverer on the wire, that is to say of the line of tangency between the cylinders 9 and 10.

Finally, as illustrated by FIG. 5, it can be envisaged to have the spindle 5 at a slightly lower level of the plane P determined by the line of tangency between the cylinders of the deliverer 3 and that between the cylinders 9 and 10, but slightly above the bottom of the grooves of the cylinder 10. This further facilitates the free rise of the torsion communicated by the spindle 5 when the deliverer 8 does not act, since any potentially harmful contact with the cylinder 9 is eliminated.

The grooves provided in the cylinder 10 must have a sufficient width to avoid pinching the fibers at the edges.

Example 1

On an installation of the type illustrated in FIG. 1, a wick 2 based on wool fibers (average length 62 millimeters), NM 2 (5,000 decitex) is treated, the drawing rate given in 4 being 20 and the speed of the outlet cylinders 3 of 200 meters per minute. As a false twist spindle, an internal friction spindle 5 is used, having a concave external surface, driven at a speed of 1800 revolutions per minute.

The winding speed of the product thread 7 is 207 meters per minute.

According to the invention, the deliverer 3 is disposed at a relatively large distance from the false-torsion member 5, this distance being in this case, equal to 27 centimeters.

Furthermore, in the immediate vicinity of the entry of the false twist spindle 5 is disposed a second deliverer 8 which acts intermittently on the wire 2 and which. allows you to vary the length of the twist upstream of the spindle.

This deliverer consists of an upper cylinder 9 having a surface 10, in Vulkolan, and whose diameter is 5 centimeters.

This cylinder 9 rests on a lower cylinder 10, having a diameter equal to 10 centimeters, that is to say having a perimeter substantially equal to twice the distance B between the spindle 5 and the deliverer 3.

The cylinder 10 has a notch on half of its periphery and is driven at a speed of 384 revolutions per minute, its peripheral speed therefore being approximately 205 meters per minute. Furthermore, at the outlet of the false twist spindle 5 is disposed a bonding device 21 making it possible to stabilize the alternating twist produced.

Under these conditions, a yarn of fibers of NM 40 (250 decitex) is obtained which has zones of alternating twist along its length, alternately of direction S and Z, each zone having a length of approximately 27 centimeters and a twist of 75 towers (in each zone).

Example 2

Example 1 is repeated, but there is incorporated immediately before entering the delivery unit 3, a core 22 constituted by a polyester thread textured by false twist, of 72 decitex 33 strands.

As the wick of fibers 2, a wick of wool (average length 62 millimeters) having an NM of 3 (3,300 decitex) is used, the drawing ratio given in 4 is 35.

At the exit of the false twist spindle, a core wire is obtained, the fiber cover of which has an alternating twist, this wire having a title of NM 60 (167 decitex).

Example 3

This assembly is illustrated by FIGS. 2 and 4 which show the production of a self-twisted wire by simultaneous treatment of two wires in accordance with the invention.

Compared to previous example 1, the only differences lie in the fact that the installation comprises a second supply system 1, 3, 4 of wires 2 and that the intermittent deliverer has two parallel grooves 33, 34 making it possible to treat the two wires 2 separately. Furthermore, separator guides 35, 36 are arranged upstream of the deliverer member 8 and a separator It is disposed near the spindle 5 (FIG. 3) so as to keep the two wires separate and to define the meeting point where the autotorsion takes place in an area which corresponds to the end of the action of the friction surface 5.

By working in the same way as in Example 1, two identical wicks 2, one obtains at the exit of spindle 5 a self-twisted thread of NM 20 (500 decitex) having zones of alternating twist of 27 centimeters in length.

Such a wire can be used as it is and is perfectly stable.

Example 4

The assembly 3 is repeated, but there is incorporated at the inlet of each call cylinder 3, a core wire 40 constituted by a polyester wire textured by false twist of 72 decitex - 33 strands.

As the wick of fibers, wicks of wool are used (average length 62 millimeters), having an NM of 3 (3300 decitex). The draw ratio given in 4 is 35. At the outlet of spindle 5, a self-twisted yarn is obtained, each of the constituents of which has a title of NM 60 (167 decitex).

Of course, the invention is not limited to the preceding exemplary embodiments, but it also covers all the variants thereof. Thus, it is possible to obtain fancy yarns, by varying the feed and / or winding speeds of the yarn (s).

Furthermore, as said previously, in particular in the case where it is desired to produce core yarns, it may be advantageous to communicate a false twist to the wire immediately at the outlet of the deliverer 3, for example by means of a pneumatic nozzle. ,

Other variants of the process could also be envisaged, for example combining the wires produced with a wire 12 (FIGS. 1 and 2) brought directly into the axis of the false twist spindle 5. Finally, the winding of the wire obtained can be produced in any known way by communicating or not a complementary twist to it.

Claims (12)

1 / Method for obtaining a wire which has alternately torsion zones of direction 3 and Z along its length, which consists, in a known manner: - to positively deliver an elementary wire (2), - to communicate to this wire (2) a false twist using a spindle (5) disposed at a distance D distant from the bodies (3) wire deliverers, - to intermittently vary the length of the twist rise upstream of the false twist member (5), so that at the exit of this member the elementary wire (2) has an alternating twist along its length , - returning the wire (7) thus formed, characterized by the fact: - that the variation in the length of the twist rise . is performed without braking the wire, . is obtained by means of a blocker (8) acting intermittently at a point located as close as possible to the element (5) communicating the false twist, - And that the duration of action of the blocker (8) corresponds substantially to the duration that a point considered of the wire (2) takes to cross the distance D between the delivery member (3) and the false twist member ( 5). 2 / A method according to claim 1, characterized in that one stabilizes the alternating torsion communicated to the wire at a point located as close as possible to the outlet of the element (5) communicating the false torsion. 3 / Method according to one of claims 1 and 2, characterized in that: - that positively delivers at least two separate elementary wires (2), - that a false twist is communicated to at least one of these wires (2), and that the length of the twist rise is varied upstream of the false twist member (5) in accordance with the claim 1, so that at the outlet of this member (5) the wire or wires thus treated have an alternate twist along their length, - And finally, that we juxtapose the two wires so as to cause their auforetordage. 4 / Method according to one of claims 1 to 3, characterized in that the false torsion is communicated by friction on a movable surface. 5 / Method according to one of claims 1 to 4, characterized in that one incorporates a core (40) during treatment of the elementary son (s), this incorporation being carried out upstream of the delivery member (3) of the or said wires (2). 6 / Method according to one of claims 1 to 5, characterized in that the wire is subjected to the action of a false twist member (23) disposed near the outlet of the delivery member ( 3) distant from the false torsion member (5). 7 / A method according to one of claims 3 to 6, characterized in that the self-twisting of the son (2) is carried out in the immediate vicinity of the exit zone of the false twist element (5). 8 / Method according to one of claims 3 to 7, characterized in that one communicates an alternating twist to two elementary son (2) by means of a single false twist member (5), the two son ( 2) being kept separate when they enter the false-twist member. 9 / Device for implementing the method according to one of claims 1 to 8, comprising means (3) for supplying wire (2), means for communicating a false twist to at least one wire (2 ) in motion, and means (8) making it possible to vary the rise in torsion upstream of the false twist spindle (5), characterized by the fact: - that the false twist element (5) is a friction pin, - And that the element (8) making it possible to vary the length of the twist rise does not cause any braking of the wire (2) and is constituted by a blocker formed by a positive deliverer (9), (10) acting intermittently on the wire, for a period equal to the time taken by a considered point of the wire (2) to cross the distance D between the wire deliverer member and the member of false twist. 10 / Device according to claim 9, characterized in that the deliverer (8) forming a blocker consists of two rollers (9), (10) positively driven one of these rollers being mounted on a support bringing it intermittently in contact with the second. 11 / Apparatus according to claim 9, characterized in that the deliverer (8) forming a torsion blocker consists of two cylinders (9), (10) one of which has, on a part of its periphery, grooves ( 32), (34) for guiding the wire, so that the wire (2) passing between these two cylinders is not delivered when it is in the groove and vice versa outside this groove. 12 / Device according to one of claims 9 to 10, characterized in that it further comprises a false twist member (23) disposed near the wire delivering member (3) located upstream of the means ( 8) allowing the torsional rise to be varied.

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