EP2763924A1

EP2763924A1 - Device for reducing the tension of yarn between a system for transforming said yarn and a system for winding said yarn

Info

Publication number: EP2763924A1
Application number: EP12773090.1A
Authority: EP
Inventors: Christophe Vega; Gilles Coral
Original assignee: Verdol SA
Current assignee: Staeubli Verdol SA
Priority date: 2011-10-04
Filing date: 2012-09-26
Publication date: 2014-08-13
Also published as: FR2980784A1; FR2980784B1; WO2013050686A1

Abstract

According to the invention, the device includes: a capstan (13) consisting of at least one motor-driven roll (15) having an evolutionary diameter over at least a portion of the length thereof, said portion comprising an intake area for the yarn (FT), the speed of rotation of said roll (15) being such that, at least at one point, the peripheral speed thereof is greater than the driving speed of the yarn (FT): - at least one yarn guide (17) positioned upstream from said roll (15), opposite the evolutionary diameter portion, said yarn guide (17) being movably mounted so as to move the intake point of the yarn; - a yarn accumulator system positioned downstream from the roll (15) and having arrangements (16) capable of absorbing a quantity of yarn; - connection means between the accumulator system and the yarn guide (17), which are shaped so as to move in one direction or another; said yarn guide moves relative to the evolutionary diameter portion of the roll on the basis of the increase or decrease in the quantity of yarn absorbed by the accumulator.

Description

DEVICE FOR LOWERING THE VOLTAGE OF A WIRE BETWEEN A SYSTEM FOR TRANSFORMING SAID THREAD AND A SYSTEM

The invention relates to the technical field of continuous elongated material processing machines, especially textile yarns, which will be referred to hereinafter by the term "yarn", according to the twisting methods, "simple torsion "," Double twist "," direct wiring "... According to these methods well known to those skilled in the art, shown schematically in Figures 1 and 2, at least one of the son worked (Fl) passes through a torsion pin (3) entering an axial and radial channel (4) of said torsion pin, opens on a cylindrical or conical portion arranged on the periphery of a plate (5) integral with the pin (3). ) and turning with this one. Given the rotation of the spindle, this wire (Fl) leaves said reserve and forms a balloon (6) which surrounds a pot or cradle (7) arranged coaxially to spindle (3) before reaching a fixed point (10). The yarn (s) thus transformed (FT) exits (ent) the system with a tension essentially determined by the combination of centrifugal force, aerodynamic forces and friction experienced by said yarn in its rotation. The yarn (s) thus transformed (FT) is (are) generally then wound (s) on a support to form a coil (14). For the coil to form properly, and in particular so that the pressure exerted by the winding does not crush the tube and is stable, the winding tension of the wire (FT) should be lowered and kept as constant as possible.

In order to lower the thread tension from the value resulting from the twisting process to that necessary to form a correct winding in the form of a spool, it is known to insert a device between the spindle and the winding system that will be designated in this embodiment. who follows by "deliverer". The transmitter is a device that pulls the wire (FT) under the voltage resulting from the upstream process and delivers it under a lowered voltage. There are two main principles of issuers, well known by those skilled in the art:

The gated emitters where the wire is subject to sinuate between two disk-shaped grids whose surfaces have corrugations or conjugate reliefs. The said grids are rotated so that their tangential velocity at the points of contact with the wire is substantially greater than the speed of travel of the wire, creating a tensile force by the effect of the friction between the wire and the wires. corrugated surfaces of grids.

Capstan-type issuers, as represented by reference numeral (13), in FIGS. 1 and 2, formed of two substantially cylindrical buckets, of parallel axis or forming an angle between them. The wire is wound by forming several turns passing successively from one bucket to the other, at least one of the two buckets being rotated at a peripheral speed equal to or greater than the speed of travel of the wire, creating a force of traction by the effect of friction between the wire and its surface.

According to the two principles stated above, the speed of travel of the wire (FT) at the output of the transmitter is fixed by the downstream system, in particular by the winding device. The present invention relates to capstan type issuers. The operation of a capstan to lower the wire tension of the value resulting from the twisting or wiring process to that required to form a proper coil-shaped winding, is well known to those skilled in the art and is described in this art. which follows in a succinct manner. For a given relative speed between the bucket surface and the wire, the tensile force exerted on the wire is substantially proportional to the winding arc of the wire on the bucket, to the local wire tension and to the coefficient of friction between the wire and the surface of the bucket. It is therefore known to adjust the winding tension by changing the number of turns of wire wound on the capstan and thus the cumulative winding arc, and / or by changing the relative speed of the capstan with respect to the speed of the wire. This relative speed is usually designated by the term "overspeed", since in order to operate to lower the tension of the thread, the peripheral speed of the motorized bucket (s) must be, at least at one point, equal to or greater than the thread running speed. Depending on the application, the overspeed can be set from zero to several tens of percent. The problem to be solved by the present invention is to obtain a constancy and a stability of the capstan output voltage and thus a constancy and stability of the winding voltage. The pulling force of a capstan and hence the output voltage resulting from the friction of the wire on the peripheral surface of the motorized bucket and therefore its "overspeed" is influenced by many factors, including:

- the input voltage on the capstan resulting from the upstream process,

the material and the structure of the wire, as well as the presence of the chemical additives (sizing) applied on the wire during upstream processes, the surface condition of the buckets of the capstan, which surface condition evolves over time due to wear, fouling and / or pollution caused by ambient conditions or by the wire,

the elasticity of the yarn, which generates a shortening due to the decrease in its tension, so that the relative velocity between the yarn and the contact surface changes within the capstan itself,

the ambient temperature and hygrometry that modifies the elasticity of the wire and the coefficient of friction between the wire and the contact surface,

the periodic variations in the running speed of the wire resulting from the reciprocating movement of the winding.

Experience has shown that variations in the winding tension, whether cyclic or in the form of slow drifts, affect the quality of the coil, its density, its ability to be unwound, the winding of wire wound ... and degrade the use made of it downstream.

In order to partially absorb the periodic variations and / or the jolts of the yarn speeds, it has been proposed to intercalate between the capstan and the winder a yarn accumulator system, for example constituted by at least one movable detent member. such as a wheel or a wire guide, and able to absorb by moving the (or) member (s) mobile (s) a length of wire, according to the known principle of the puppets on the winding systems. This solution solves only partially the problems posed. More sophisticated systems for regulating the voltage at the capstan output have been proposed, based for example on the installation of a voltage sensor associated with an electronic processing acting on the overspeed, but these systems are particularly expensive. Especially for twisting or cabling machines, consisting of an alignment of With many work positions side by side, this solution requires providing each working position with an individual motor and an individual servo system, instead of a conventional collective capstan drive system.

Now it has been found, and it is the object of the present invention a device applicable to lower the tension of a wire between the twisting system or direct wiring and the winding system to make the winding voltage more constant and more stable.

According to the invention, the device comprises:

a capstan composed of at least one motorized cup having on at least a part of its length an evolutionary diameter, said part constituting a zone of entry of the wire, the speed of rotation of said bucket being such that at least in one point, its peripheral speed is greater than the drive speed of the wire;

at least one wire guide positioned upstream of said bucket, at the right of the portion of evolving diameter, said wire guide being mounted with displacement capacity so as to move the point of entry of the wire;

- An accumulator system of the wire positioned downstream of the bucket and having arrangements capable of absorbing a quantity of wire;

connecting means between the accumulator system and the wire guide shaped to move in one direction or the other, said wire guide relative to the portion of the bucket's progressive diameter as a function of the increase or decrease the amount of wire absorbed by the accumulator.

The connection between the mobile element (s) of the accumulator system and the wire guide can be carried out according to any mechanical means known by those skilled in the art, such as, by way of non-limiting examples, a system of rods, angle gears, screw nut, cams, etc.

Many embodiments of the mechanical connection may be suitable for carrying out the invention since the forces to be provided by the mobile element (s) of the accumulator system for actuating the movement of the wire guide are substantially lower, and preferably less than 50% of the forces applied by the wire on said (or said) element (s) mobile (s).

According to an important aspect of the invention, the tension exerted by the mobile element (s) on the wire determining the winding voltage is substantially constant whatever the position of said element (s) ( s) mobile (s). According to a preferred embodiment, said tension exerted on the wire is obtained by the own weight of (or) movable elements.

According to an alternative embodiment of the invention, this tension is obtained by the action of a spring or by a combination of its own weight and the action of a spring. The action of the spring can be adjustable for example by moving its attachment point

According to another variant embodiment, this tension is obtained by the action of a jack to which an adjustable pressure is applied.

The invention will be better understood with reference to the following figures.

FIG. 1 is a general diagram explaining the direct wiring method according to the state of the art, FIG. 2 is a general diagram explaining the double twist process according to the state of the art,

FIG. 3 is a general diagram of the device according to the invention. FIG. 4 is a general diagram of the device according to the invention, when the quantity of yarn absorbed in the accumulator system decreases,

FIG. 5 is a general diagram of the device according to the invention, when the quantity of yarn absorbed in the accumulator system increases,

FIG. 6 shows a first example of an embodiment of the mechanical connection between the accumulator system and the wire guide in top view,

FIG. 7 shows a second exemplary embodiment of the mechanical connection between the accumulator system and the wire guide in top view,

Figure 8 shows a second exemplary embodiment of the mechanical connection between the accumulator system and the wire guide in side view. As indicated, the invention relates to the technical field of wire processing machines according to the twisting methods, "single twist", "double twist", "direct wiring", shown schematically in Figures 1 and 2. We refer to the analysis that is made in the introductory part of the description.

According to the invention, it has been designed and developed a device adapted to lower the tension of the thread (FT) between the twisting or cabling system direct (3 to 10) and the winding system (14) to make the winding voltage more constant and more stable.

According to a particularly advantageous embodiment of the invention, the device comprises the following elements considered in combination:

a) a capstan (13), of which at least one of the cups (15) has a conical shape or a change of diameter over at least a part of its length situated in the zone of entry of the wire, and of which at least one of cups is motorized to rotate at such a rotational speed that its peripheral speed is, at least at one point, greater than the speed of the wire,

b) at least one wire guide (17) disposed at the entrance of said capstan (15), placed in line with the conical shape or with a progressive diameter arranged on the bucket (s) (15) and provided with a displacement capacity said wire guide is arranged, so that its displacement modifies the point of entry of the wire (FT) on said (or said) part (s) conical (s). According to a preferred embodiment, the displacement of the wire guide (17) is substantially parallel to the axis of the conical portion (s),

c) a yarn accumulator system, comprising at least one movable detent member (16), such as a wheel or a yarn guide, arranged (s) downstream of the capstan (13), and able to absorb, by the moving (or) movable member (s) (16), a length of yarn according to the known principle of the puppets,

d) a mechanical connection (18) between the movable member (s) (16) of said accumulator system and said wire guide (17) at the inlet of the capstan (13), which mechanical connection (18) ) has the function of moving the wire guide (17) according to the displacement of the movable member (s) (16), so that:

- When the amount of wire (FT) absorbed by the accumulator device increases, the wire guide (17) is moved towards the small diameter of the (or) portion (s) conical (s) or diameter of evolution for the wire (FT) enters on a smaller diameter,

when the amount of thread (FT) absorbed by the accumulator device decreases, the thread guide (17) is displaced towards the large diameter of the conical part (s) or of progressive diameter so that the wire (FT) enters on a larger diameter.

The operation of the device according to the invention is explained below. The pulling force of the wire (FT) by the capstan therefore results from the friction of the peripheral surface of the motorized bucket and therefore its "overspeed" with respect to the wire.

When an evolution of the parameters which influence this force tends to increase it, the pulling force of the wire (FT) by the capstan becomes too high and therefore the quantity of wire delivered per unit of time increases. The excess quantity of delivered wire is absorbed by the accumulator system which causes displacement of the mobile member (s) (16) of said accumulator system. The mechanical link (18) transmits this movement to the wire guide (17) so that the wire (FT) approaches the capstan to a smaller diameter. As a result, the wire approaches the bucket at a point where the peripheral speed of the bucket is smaller, reducing the frictional force, and hence the tensile force of the wire. Conversely, when a change in the parameters which influence this force tends to reduce it, the pulling force of the thread (FT) by the capstan becomes too small and therefore the quantity of thread delivered per unit of time is reduced. The quantity of deficient wire delivered is returned by the accumulator system which causes a displacement in the opposite direction of (or) movable member (s) (16) of said accumulator system. The mechanical link (18) transmits this displacement to the wire guide (17) so that the wire (FT) approaches the capstan to a larger diameter. As a result, the wire approaches the bucket at a point where the peripheral speed of the bucket is greater, increasing the frictional force, and therefore the pulling force of the wire.

It follows from these explanations that the device permanently establishes a correction of the efficiency of the capstan to maintain a quantity of accumulated wire substantially constant, and therefore a winding voltage downstream of the substantially constant device.

The mechanical connection between the mobile element (s) (16) of the accumulator system and the wire guide (17) can be carried out according to any means known to those skilled in the art, such as , as non-limiting examples, a system of connecting rods, angle references, screw nut, cams, etc.

Many embodiments of the mechanical connection may be suitable for carrying out the invention as long as the forces to be provided by the mobile element (s) (16) of the accumulator system to actuate the movement of the wire guide (17), are substantially lower, and preferably less than 50% of the forces applied by the wire (FT) on said (or said) element (s) mobile (s) (16). Two examples of embodiment of the mechanical connection between the accumulator system and the wire guide according to the invention are given in the following. According to a first exemplary embodiment of the invention, illustrated in FIG. 6, the accumulator system consists of a wheel (16) disposed at the end of an arm (19) mounted with angular displacement capacity around an axis (20) and connected to the wire guide (17) by a link (22). The increase or decrease in the amount of thread (FT) accumulated, results in a rotation of the arm (19), which rotation is transformed by the rod (22) in a translation of the guide wire (17), parallel to the the axis of the bucket (15).

According to a second exemplary embodiment of the invention, illustrated by FIGS. 7 and 8, the accumulator system consists of a wheel (16) disposed at the end of an arm (19) having a displacement capacity angularly about an axis (20) associated with a support (21) of the guide wire (17) by a screw-nut system. The increase or decrease in the amount of thread (FT) accumulated, results in a rotation of the arm (19), which rotation is converted into a translation of the support (21) of the guide wire (17). By way of example, the direction and the screw pitch of the screw nut system are chosen so that a + 15 ° rotation of the arm relative to the horizontal causes a translation of about 3 mm from the wire guide ( 17) towards the large diameter of the bucket (16) and that a rotation of -15 ° of the arm relative to the horizontal causes a translation of about 3 mm from the guide wire (17) towards the small diameter bucket (16).

According to an important aspect of the invention, the tension exerted by the movable member (s) (16) on the wire guide (17) determining the tension of winding, is substantially constant regardless of the position of said (or said) element (s) mobile (s) (16). According to a preferred embodiment, said tension exerted on the wire (FT) is obtained by the own weight of the mobile element (s) (16).

In the two examples of embodiment previously described and illustrated in FIGS. 6, 7 and 8, it is advantageous to design the arm (19) and its wheel (16) such that they have a substantially horizontal average position, and a capacity of rotation preferably of plus or minus 15 ° around this position, and that they have a weight and a center of gravity such as compared to the wheel (16), they represent a force substantially equal to twice the winding tension desired. Thus, because of the moufflage around the wheel, the arm (19) and the wheel (16) exert on the wire a voltage equal to the desired winding voltage.

According to an alternative embodiment of the invention, this tension is obtained by the action of a spring or by a combination of the own weight of the mobile element (s) (16) and the action of a spring. The action of the spring can be adjustable for example by moving its attachment point

The advantages of the invention are apparent from the description.

The invention can be realized with simple and relatively inexpensive mechanical means. The drift of the parameters influencing the efficiency of the capstan, are compensated by the device object of the present invention. By way of example, the following test was carried out by direct wiring of polyester threads. A machine in operation has been voluntarily subjected to variations in ambient temperature of 22 ° C to 45 ° C and humidity variations of 50% to 85%. Such variations have resulted, in the absence of the device object of the invention, by variations of coils voltages of plus or minus 50 grams around a mean winding voltage of 150 grams. With the device object of the invention, under the same conditions of experimentation, the variation of the winding voltage has been reduced to plus or minus 20 grams around the average value of winding.

Such an improvement in the regularity of the winding tension during production, results in a strong improvement of the yarn quality (density, stability, and residual tension of the yarn) in the reel. This results in a significant improvement in yarn quality and productivity in downstream processes including the breakage rate at reeling, and the accuracy of the wound wire metric.

Claims

-1- Device for lowering the tension of a thread (FT) between a system for converting said thread and a winding system for said thread, characterized in that it comprises:

a capstan (13) composed of at least one motorized bucket (15) having on at least part of its length an evolutionary diameter, said part constituting a zone of entry of the wire (FT), the speed of rotation of said bucket ( 15) being such that at least at one point its peripheral speed is greater than the wire drive speed (FT):

at least one wire guide (17) positioned upstream of said bucket (15), in line with the portion of evolving diameter, said wire guide (17) being mounted with displacement capacity so as to move the point of entry of the wire ; an accumulator system of the wire positioned downstream of the bucket (15) and having arrangements (10) capable of absorbing a quantity of wire; connecting means between the accumulator system and the yarn guide (17) shaped to move in one direction or the other, said yarn guide moves relative to the scalable diameter portion of the bucket as a function of the increase or decreasing the amount of yarn absorbed by the accumulator.

-2- Device according to claim 1, characterized in that the accumulator system comprises at least one movable detent member (16) adapted to absorb under a displacement effect, the amount of wire.

-3- Device according to any one of claims 1-2, characterized in that the connecting means between the accumulator system and the guide wire (17) are of the mechanical type (18) for moving the wire guide according to the displacement of the diverting member (s) so that:

when the amount of thread (FT) absorbed by the accumulator system increases, the thread guide (17) is moved to the small diameter of the evolving diameter portion so that the thread (FT) enters a smaller diameter, when the amount of wire (FT) absorbed by the accumulator system decreases, the wire guide (17) is moved towards the large diameter of the evolving diameter portion for the wire (FT) to enter a larger diameter.

-4- Device according to any one of claims 1-3, characterized in that the forces to be provided by the movable detour member (16) to actuate the movement of the guide wire (17 are less important than those applied by the wire on said movable detent member (16);

-5- Device according to any one of claims 1-4, characterized in that the moving detent member (16) is a caster attached to the end of an arm mounted with angular displacement capacity around a axis and connected to the wire guide by a link (22) to allow translational movement of said wire guide (17).

-6- Device according to any one of claims 1-4, characterized in that the moving detent member (16) is a caster attached to the end of an arm (19) mounted with angular displacement capacity around an axis (20) and connected to the wire guide (17) by a screw-nut system (21) to allow translational movement of said wire guide. -7- Device according to any one of claims 1-6, characterized in that the tension exerted by the movable detour member is substantially constant regardless of its position. -8- Device according to any one of claims 5 and 6, characterized in that the arm (19) equipped with the wheel (16) has a substantially horizontal average position with angular displacement capacity relative to this position of more or minus 15 °. -9- Device according to any one of claims 5, 6 and 8, characterized in that the weight and the center of gravity of the arm (19) equipped with the wheel (16) represents a force substantially equal to twice the winding voltage so that, under the effect of moufflage, the arm and the wheel exert on the wire a voltage equal to the desired winding voltage.