WO2004104283A2

WO2004104283A2 - Device for regulation and control of the stability of the tension balance in a synthetic thread

Info

Publication number: WO2004104283A2
Application number: PCT/FR2004/001207
Authority: WO
Inventors: Carlos Matas; Philippe Flechon
Original assignee: Rieter Textile Machinery France
Priority date: 2003-05-19
Filing date: 2004-05-17
Publication date: 2004-12-02
Also published as: FR2855189A1; FR2855189B1; WO2004104283A3

Abstract

The device finds application in a texturising machine of the type comprising, successively, a take-up body (A) for removing said thread (F) from a supply reel (B), a means for locking the twist (C), an oven (D), a cooling zone (E), a means (H) for twisting the thread and a second take-up body (G) for the thread. The cooling zone (E) comprises means (2a, 2b, 2c), for guiding the thread of which one at least can be displaced to modify one of the parameters of the contact continuity of the thread and, in a similar manner, the value of the tension of the thread between the inlet and the outlet of said cooling zone (E), with regard to adjusting the same with relation to nominal values.

Description

DEVICE FOR ADJUSTING AND CONTROLLING THE STABILITY OF THE TENSION OF A WIRE

SYNTHETIC.

The invention relates to the technical field of texturing machines, in particular those equipped with friction pins.

In a perfectly known manner, for a person skilled in the art, according to the principle underlying texturing, a synthetic yarn is unwound from a supply reel by means of a call member, then passes successively through a torsion blocking device, an oven, a cooling zone, a friction pin and a second call member. The difference in speed between the first and the second caller, determines a rate of drawing of the wire, while the spindle imposes a twist on the wire on itself, which twist is obtained by friction by applying the wire on a moving organ. This twist extends throughout the wire to the twist blocker. The twisted yarn is placed in the oven to be subjected to a determined temperature to regain its plastic state. At this temperature, the wire becomes longer due to stretching, the twist resulting in a plastic deformation giving the appearance of a crimp. Still in the twisted state, the wire is subjected to the action of the cooling zone to restore the material to its stability and consequently memorize the elongation and crimping of said wire.

Different technical solutions have been proposed for the realization in particular of the furnace, the cooling zone and the friction spindle. For example, the oven can consist of a heated track on which the wire is plated. The contact of the wire along this track ensures its heating.

To ensure contact of the wire over the entire length of the oven, the track is slightly curved, so that the wire tension guarantees sufficient contact pressure so that the wire reaches the required temperature level.

As regards the cooling zone, the latter is generally constituted by a cold surface, in the form for example of a track having a groove in which the wire is guided. The contact line at the bottom of the groove has a convex curvature to ensure the continuity of the contact under the effect of its tension. In another embodiment, the cooling zone may consist of a cylinder (or a convex surface) around which the wire is interwoven, that is to say wound in a helix. This solution appears for example from patent EP 0 744481.

As regards the friction pin, the latter is, in a known embodiment, constituted by three parallel axes arranged at the top of a substantially equilateral triangle. Each of the axes carries a stack of discs separated by spacers, the radius of which is substantially greater than the distance from the top of the triangle and its center. The discs are therefore nested one inside the other. The wire, inserted between the discs, is forced to pass in the center of the equilateral triangle, between the axes, in a manner substantially parallel to the latter and to bypass each disc by interlocking on it. Under the effect of the rotation of discs, the contact pressure of the wire on the latter, causes a friction twist of the wire on itself.

In view of these provisions, it follows that, for the most part, the means for transferring mechanical movements and the means for thermal transfer are ensured by pressure of the wire on the surfaces, so that it is difficult to ensure the stability of such a process.

For a good understanding of the continuation of the description, one will designate by (Tl), the tension of the wire between the exit of the torsion blocker and the entry of the oven, by (T2) the tension of the wire at the exit of the oven and the entry of the cooling zone, by (T3) the tension of the wire between the exit of the cooling zone and the entry of the torsion spindle, by (T4) the tension of the wire between the exit of the spindle torsion and the second appeal body or deliverer.

The stability and balance of the texturing process depend on the value of the above-mentioned tensions, which depend on the elasticity and the plasticity of the yarn with regard to its elongation due to the speed difference between the first and second calls. and the distribution of the voltage differences along the path of the wire resulting from friction.

Since, in most texturing machines, the geometry of the oven tracks and the cooling zone is fixed at the time of design, the adjustment of the tension balance of the yarn essentially depends on the configuration of the spindle friction and the choice of speed and temperature parameters. The purpose of adjusting the tension balance is to obtain the required level of wire crimp by minimizing the wear of the wire by the contacts and friction on the various components, in order to keep the tenacity as high as possible. , seeking to perform these operations at the highest possible speed.

It therefore seems important to be able to configure the torsion pin so that it gives the wire a sufficient level of torsion for the wire to memorize the expected crimp. Such a tension must be perfectly stable, which is difficult to obtain, since the friction drive is not positive, since the thread slides on the disc.

Different solutions can be envisaged for adjusting the rotational friction friction capacity of the wire by the discs.

It is for example possible to vary the number of discs. This multiplies the number of contact zones and therefore the surface on which friction is exerted.

Another known means consists in modifying the coefficient of friction between the wire and the disc by choosing for example a polyurethane disc which has a better coefficient of adhesion compared to a ceramic disc, or by modifying the surface condition of the disk.

It is also possible to control this friction, to modify the level of overlapping of the discs. Indeed, the more the discs overlap, the more the wire is constrained to wrap around each of them to bypass it, which has the effect of increasing both the length and contact pressure. To adjust this overlap, select the diameter of the discs.

These various operations require significant manual intervention in the assembly and disassembly of the discs with the obligation to increase the number of sets of discs in stock.

Another way to adjust this overlap is to change the distance between the axes of the discs, that is to say the side of the equilateral triangle at the top of which the axes are positioned. The modification of the center distance is generally carried out when stopped by means of shims or rigid locking means, to then allow the spindle to be driven at high speed, without vibration. To keep the equilateral shape of the triangle formed by the axes, it is necessary to move at least two of the latter, so that the mechanical rotation of the shafts must allow such a variation in center distance, requiring means of implementation. complex (pulley system, belts, ...).

It follows from the above that optimizing a spindle is a difficult operation which should be carried out for each type of yarn and which requires heavy interventions on the texturing machine.

Importantly, another problem known to those skilled in the art in the field of texturing machines is the stability of the voltage balance during production.

For a given configuration, it is possible to adjust, at least in theory, the voltages (Tl, T2, T3, T4), provided that there are no other parameters capable of influencing the _. process. Other parameters can intervene: * the coefficient of friction between the yarn and the different texturing organs which depends in particular:

- twisting of the wire,

- the surface condition of the parts in contact, - fouling and pollution,

- the size ratio;

* the elasticity of the thread which depends in particular:

- its title,

- its torsion, - its temperature.

Among other disadvantages, we can note the cyclical instabilities due to the mutual influences of the parameters between them causing phenomena of drift or pumping. Thus, we observe, from a certain speed, an increase in torsion until the moment when the overvoltage thus created causes a decrease in the coefficient of friction causing, conversely, a slip of the wire and therefore a decrease in the tension of torsion until the coefficient of friction goes up, and so on. This so-called “pumping” phenomenon limits the rise in speed of texturing machines of the false twist type equipped with friction pins.

It has been proposed, to detect and monitor such instabilities or drifts, to place between the spindle and the second call system, a voltage sensor in order to measure the voltage (T4). In fact, it has been observed that part of the phenomena previously exposed result in a variation of the voltage (T4). It therefore appeared important to be able to monitor it and detect any drift by comparing it to minimum and maximum thresholds. From the analysis of the prior art, the invention proposes to remedy the drawbacks previously developed and to solve the problem posed which is to regulate and control the stability of the voltage balance of a synthetic yarn in a texturing process.

To remedy the aforementioned drawbacks and solve the problem posed, a device has been designed and developed applicable in a texturing machine of the type comprising that successively, in combination with sensors capable of measuring the state of the yarn:

- a call member for unwinding said wire from a supply reel;

- a means of locking the torsion;

- an oven ; - A cooling zone delimiting a surface on which the wire is pressed, so that the contact line between said wire and said surface is, essentially, convex to ensure continuity of contact under the effect of the tension of the wire;

- a friction pin (or other equivalent means); - a second wire calling device.

According to the invention, the cooling zone has means for guiding the wire, at least one of which is movable to modify one of the parameters of the contact continuity of the wire and, concomitantly, the value of the tension of said wire between the inlet and the outlet of said cooling zone in order to adjust them with respect to nominal values. It will be recalled that the friction of the wire on the cooling track causes a difference in tension of the wire between the input contact point and the point where the wire leaves this contact at the output. This difference in tension depends on the coefficient of friction, but also on the length and the interlocking of the angle characterizing the change of direction of the wire by its contact on the surface of the cooling zone and the radius of curvature of the contact line between the wire and said surface.

To solve the problem posed of subjecting the wire in the cooling zone to a helical movement, the means for guiding the wire are mounted along the cooling zone, so that when passing from one means to another, the wire is wound on the convex surface so that the contact line of said wire follows a substantially helical trajectory.

For this purpose, one of the guide means is mounted at the entrance to the cooling zone, the other being mounted at the exit from said zone substantially in alignment, at least one other means being mounted between the two preceding ones, over a part of the cooling zone and in an angularly offset manner with respect to said alignment, so that the line of contact of the wire follows a helical trajectory oriented in one direction between the inlet guide means and the one or more intermediate guide means (s) and in the opposite direction between the said intermediate guide (s) and the outlet guide means.

Advantageously, the intermediate guide means or means is (are) mobile, while the inlet and outlet guide means are fixed. From this basic design, different embodiments can be envisaged.

In a first embodiment, the different guide means are carried by the convex surface, the mobile guide means (s) is (are) mounted on one or more rotating parts ( s) of said convex surface, the inlet and outlet guide means being mounted on a fixed part of the convex surface.

In another embodiment the movable guide means (s) is (are) mounted on the convex surface which is capable of being angularly driven as a whole, the inlet guide means and output are independent of said surface, to be fixed.

To solve the problem posed of modifying at will the position of some of the guide members so as to concomitantly adjust the tension of the thread, each movable part receiving the movable guide means (s), is subject to an actuator member capable of ensuring precise positioning, said actuator member being controlled by an electronic computer.

The computer can therefore automatically carry out the positioning of the mobile guide means (s) at nominal value when starting the texturing process. It is therefore possible to choose a position of the movable member adapted to the worked wire.

According to another characteristic, the computer is subject to the various sensors measuring the state of the wire at different points of its course. These sensors can measure tension, temperature, twist, crimp or any combination of these characteristics.

In a preferred form of the invention, these sensors give information representative of the thread tension.

The computer is programmed to carry out the corrections, either: - of the wire tension difference or ratio between sensors placed upstream of the cooling zone and sensors placed downstream of said zone; - The difference or ratio of thread tension between sensors placed upstream of the friction pin and at least one sensor placed at the outlet of said pin.

More generally, the computer is programmed to perform any other measurement to give similar information.

According to one embodiment of the invention, the cooling zone is constituted by at least one rectilinear assembly of elongated shape of convex cross section, in particular cylindrical. The fixed and mobile guide means consist of bars, in particular made of ceramic.

The invention is set out below in more detail with the aid of the figures of the appended drawings in which: - Figure 1 is a schematic view of the principle of texturing by false twist;

- Figure 2 is, on a larger scale, an embodiment of the cooling zone in the form of a cylinder;

- Figure 3a corresponds to the launch position; - Figure 3b corresponds to the working position;

- Figure 3c shows the adjustment relative to the working position of the guide means for changing the angle of the wire and therefore the length and curvature of the contact line of the wire; - Figure 4 is a schematic perspective view showing an embodiment for driving and changing the angular positioning of one of the wire guide means;

- Figure 5 is a view similar to Figure 4 showing another embodiment. As shown in Figure 1, the device according to the invention is applicable to a texturing machine of the type that successively comprising, in a known manner, a first call member (A) for the unwinding of the wire (H) from a supply coil (B), a tension blocker assembly (C), an oven (D), a cooling zone (E), a friction pin (H) and a second call member wire (G). Several sensors, in particular of voltage, (Tl, T2, T3, T4) can be respectively arranged at the entry of the furnace (D) (sensor (Tl)), at the entrance of the cooling zone (sensor (T2) ), at the outlet of the cooling zone (sensor (T3)), and at the outlet of the friction pin (F) (sensor (T4)).

It is recalled, in a known manner, that the difference in speed between the first call member (A) and the second call member (G) determines a rate of drawing of the wire (F), the spindle (H ) imposes a twist of said wire on itself. This twist is obtained by friction by applying the wire to a moving organ. The twist thus imparted to the wire propagates along the latter to the tension blocker (C). The yarn thus twisted circulates in the oven (D) supporting a temperature such that its material regains a plastic phase. At this temperature, the wire, under the effect of drawing, lengthens, the torsion resulting in a plastic deformation resembling a crimp. The wire is cooled along the area (E), in the twisted state, in order to restore the material to its stability and thus memorize the elongation and crimping of said wire.

As shown in particular in Figure 2, the cooling zone

(E) consists of a surface on which the wire (F) is pressed, and designed so that the contact line between the wire and the surface, is essentially convex to ensure continuity of contact under the effect of thread tension.

For example, the cooling zone consists of at least one cylinder (1). In combination with the cooling cylinder (1), there are suitably mounted guide members (2a, 2b, 2c) of the wire (F), for example in the form of ceramic bars. The guide members (2a, 2b, 2c) are arranged so that, passing from one guide member to another, the wire is wound on the cylinder (1) so that the contact line follows said cylinder in a substantially helical shape for example.

According to this embodiment, one of the members (2a) can be disposed at the inlet of the cooling cylinder (1), the other member (2c) being disposed at the outlet of the cylinder, while the member ( 2b) is arranged between the two previous ones, being angularly offset with respect to the axis (x-x ') of the cylinder. It follows that the contact line delimits a helical path in a direction between the guide member (2a) and the intermediate guide member (2c), and in the opposite direction between said intermediate guide member (2b) and the guide member (2c).

According to a characteristic underlying the invention, at least one of the guide members (2b) is adjustable in position to modify one of the parameters of contact continuity of the wire and, concomitantly, the value of the tension of the latter between the inlet and the outlet of the cooling cylinder (1) in order to adjust them with respect to nominal values. In other words, at least one of the guide members (2b) is subject to means for being angularly displaced relative to the other two members (2a) and (2c), so as to modify the angle of the propeller and consequently the length and the curvature of the contact line of its various guide members.

According to a preferred embodiment but which should not however be considered as strictly limiting, the intermediate guide member (2b) is made mobile while the other two guide members at the inlet (2a) and at the outlet (2b) of the cylinder (1) are made fixed.

For example, according to one embodiment, the different guide members (2a, 2b, 2c) are carried by the cylinder (1), the movable guide member (2b) is mounted on a rotating part of the cylinder (1 ) constituted for example by a ring (3), the inlet (2a) and outlet (2c) guide means are mounted on a fixed part of the cylinder (1).

According to another embodiment, the mobile guide means (2b) is mounted on the cylinder (1) which is able to be driven angularly as a whole. The inlet (2a) and outlet (2c) guide means are independent of the cylinder (1) to be fixed.

The rotating part receiving the movable guide means (2b) is subject to a positioning member (4) capable of ensuring precise angular positioning on the corresponding guide member. This actuator member can be constituted by an actuator, a servomotor, a motor step by step, .... The actuator member (4) is controlled by an electronic computer (5), which is subject to the various voltage sensors (T1, T2, T3, T4) (Figure 1).

Advantageously, the actuator member (4) can allow greater movement of the movable guide member (2b) itself positioned in alignment with the fixed guide members (2a) and (2c) and the cooling cylinder, to facilitate the introduction of the wire (F) in a straight line, either manually or by any automatic means.

The computer (5) is subject, as indicated, to the sensors (Tl, T2, T3, T4) which provide information representative of the thread tension by comparing it to the nominal values. The computer is programmed to make the corrections either: - of the difference or ratio of thread tension between the sensors (T1) and (T2) placed upstream of the cooling zone and the sensor (T3) passed downstream of said zone cooling ; - the difference or ratio of thread tension between the sensors placed upstream of the torsion pin (H) and the sensor (T4) placed at the outlet of said pin (H).

These corrections are made within ranges limited by preprogrammed minimums and maximums corresponding to a normal range of variation compatible with the quality of the wire to be produced. Beyond these limits, the computer will issue an alert or a decision to stop the texturing process to avoid producing yarn under conditions outside acceptable limits. In an advantageous embodiment, the movement of the movable guide member can be extended until complete alignment of the other guide members to facilitate the engagement of the wire either manually or automatically. Similarly, the sensors placed on the path of the wire (F) can be individually monitored by the computer (5) which can thus detect a drift in the texturing process, even if the device for controlling the position of the movable axis is capable of partially compensating for effects at the level of the cooling zone or track. The limits of the correction, as well as the minimum and maximum thresholds of the other sensors are chosen by the user to allow compensation for tolerated variations in yarn count, draw rate or sizing rate of raw materials, as well as variations in operating conditions, reducing variations in the quality of the resulting wire. Within these same limits, the computer is able to stabilize the cyclic voltage variations and therefore to postpone the initiation of pumping phenomena and consequently to increase the production speeds.

The advantages are apparent from the description.

Claims

RE V E N D I C A T I O N S

-1- Device for adjusting and controlling the stability of the tension balance of a synthetic yarn during production of a texturing machine of the type comprising that successively, in combination with sensors capable of measuring the wire condition:

- a call member (A) for unwinding said wire (F) from a supply reel (B); - a means for locking the torsion (C);

- an oven (D);

- a cooling zone (E) delimiting a surface on which the wire is pressed (F), so that the contact line between said wire and said surface is, essentially convex, to ensure continuity of contact under the effect of thread tension;

- a means (H) for twisting the wire;

- a second call member (G) of the wire; characterized in that the cooling zone (E) has means for guiding the wire (2a, 2b, 2c) at least one of which is movable to modify one of the parameters of the contact continuity of the wire and, d 'concomitantly, the value of the tension of said wire between the input and the output of said cooling zone (E) in order to adjust them with respect to nominal values.

-2- Device according to claim 1, characterized in that the guide means (2a, 2b, 2c) of the wire (F) are mounted along the cooling zone, so that passing from a means to the other, the wire is wound on the convex surface so that the contact line of said wire follows a substantially helical trajectory. -3- Device according to claim 2, characterized in that one of the guide means (2a) is mounted at the inlet of the cooling zone (E), the other (2c) being mounted at the outlet of said zone substantially in alignment, at least one other means being mounted between the two preceding ones, on a part of the cooling zone and in an angularly offset manner with respect to said alignment, so that the contact line of the wire follows a trajectory in a helix oriented in one direction between the inlet guide means and the intermediate guide means (s) and in the opposite direction between the said intermediate guide means (s) and the exit guide.

-4- Device according to claim 2, characterized in that the intermediate guide means (s) (2b) is (are) mobile, while the inlet guide means (2a) and outlet (2c) , are fixed.

-5- Device according to claim 4, characterized in that the different guide means are carried by the convex surface, the mobile guide means (s) (2b) is (are) mounted on one or more rotating part (s) of said convex surface, the inlet (2a) and outlet (2c) guide means being mounted on a fixed part of the convex surface.

-6- Device according to claim 4, characterized in that the movable guide means (s) (2b) is (are) mounted (s) on the convex surface which is capable of being angularly driven in its together, the inlet (2a) and outlet (2c) guide means are independent of said surface, to be fixed. -7- Device according to claim 1, characterized in that each movable part receiving the movable guide means or is subject to an actuator member (4) adapted to ensure precise positioning, said actuator member (4) being controlled by a electronic computer (5).

-8- Device according to claim 7, characterized in that the computer (5) is subject to various sensors capable of measuring the condition of the wire by being programmed to make the corrections, namely, in particular:

- the difference or ratio of thread tension between sensors placed upstream of the cooling zone and of sensor placed downstream of said zone;

- The difference or ratio of thread tension between sensors placed upstream of the friction pin and at least one sensor placed at the outlet of said pin.

-9- Device according to claim 1, characterized in that the cooling zone is constituted by at least one rectilinear assembly of elongated shape of convex cross section in particular cylindrical (1).

-10- Device according to claim 1, characterized in that the fixed guide means (2a) and (2c) and mobile (2b), are constituted by bars, in particular ceramic.