EP1261543B1 - Method for making tapered yarn windings - Google Patents

Abstract

The invention concerns a method for making a tapered yarn bobbin obtained by depositing superposed layers (L3) of a yarn on a cylindrical support (20) with a longitudinal axis (X), and comprising a base cone (12) with generatrix (L2), and a winding cone (13) with genratrix (L3) and a main body (11) with generatrix (L1) inclined relative to the axis (X) and linking the two generatrices (L2, L3) of the two cones (12, 13). The method is characterised in that it comprises two lags for displacing a yarn guide, one first lag enabling to form part of the base cone (12), the last yarn layer deposited along said first lag up to the end of the winding cone, and a second lag enabling to terminate said started base cone (12) and to form simultaneously the main body (11) and the winding cone (13), the first yarn layer deposited along the second lag being parallel to the last layer deposited along the first lag.

Description

The invention relates to the manufacture of windings son such as glass son, and more particularly the manufacture of frustoconical windings.

Wire windings in the form of coils are a common means of temporary wire storage for subsequent feeding of yarn processing machines, for example textile machines.

A spool of yarn is formed by combining a series of filaments into a single yarn, which is collected on a rotating support where it is wound into a reel.

In the case of glass strands, glass filaments obtained by the flow of molten glass are drawn through orifices of a spinneret. These filaments are then coated with a size by a coating device so as to facilitate the fiber drawing and the gathering of the filaments into a wire, and to increase their mechanical properties, especially aging. Then these filaments are joined to an assembly device to give birth to the winding wire. The wire coming from the assembly device is wound around a support arranged in a horizontal plane perpendicular to the vertical plane of arrival of the wire, and animated by a rotary motion at a constant speed. In the usual way, the winding wire runs on the surface of a wire guide located between the assembly device and the support, and moving in a reciprocating movement parallel to the longitudinal axis of the support. rotation.

The resulting coil of yarn is called cake. However a cake is rarely used directly for the feeding of yarn of textile machines for example. Indeed, textile machines operate at high speed and the wire must then be easily removed from the coil avoiding any friction that could cause a break, which is difficult to achieve from cakes. It is then necessary to manufacture, from these intermediate coils called cakes, cylindrical coils whose yarn is twisted.

But to avoid these various steps, cake making, and then unwinding to achieve a new winding yarn previously underwent a twist, which are long and require many means, it was undertaken to form frustoconical coils without making cake intermediate whose thread is directly from the die and not twisted. The frustoconical shapes make it possible not to twist the wire and facilitate the feeding at high speed, the wire being driven along the axis of the coil towards his diameter and deviates immediately from the coil as soon as a turn detaches.

FR 2 703 671 discloses a method of winding yarn for the formation of a frustoconical bobbin from a drawn yarn directly from a die and having not undergone any torsional operation . The wire which is routed through the wire guide is wound around a support fixed at its base on a sidewall and arranged vertically, the wire guide moving in a back-and-forth movement parallel to the longitudinal axis. of the support. To achieve the frustoconical shape of the coil, the proposed solution is the use of a drawing device placed after the filament assembly device, and a dancer roll disposed between the drawing device and the guide-guide. thread. The dancer roll can rotate freely about its axis which is fixed to the end of a spring-biased arm, which makes it possible to impose on the winding wire a predetermined tension.

The frustoconical shape of the coil whose base consists of the sidewall is then obtained by assigning a constant value to the rotational speed of the drawing device and by slaving the speed of movement of the wire guide and the speed of rotation of the support.

However, such a solution requires a new structure of the implementation device by, on the one hand, a winding of the wire on a support arranged vertically, and on the other hand, by the use of a drawing device and a roller dancer. Technical modifications of existing structures are therefore important to achieve, which is not without generating some significant financial investments in a manufacturing plant.

In addition, the association of a flank at the base of the support is not without causing problems of precision as for the deposition of the wire in this zone. Thus, the yarn at the sidewall may be either deposited in excess, which leads to unwinding the package rise, causing the breakage of the wire, or deposited fault causing then the wire twisting unwinding by its nip between different layers of turns.

Finally, for coils of this type whose yarn has not undergone a twisting operation and does not exhibit any waviness, it is common to encounter problems of yarn deterioration because the crossing of the untwisted yarn that is to say the angle between two intersecting turns, is insufficient. Indeed when this angle is too small, in case of jamming of a filament of the wire between two turns of the coil, the Continuity of unwinding will result in the location of jamming the loss of one or more filaments of the yarn causing the deterioration of the yarn and the formation of a ring by the accumulation of the filament.

To avoid these unwinding problems, it may be preferred a frustoconical coil whose two frustoconical basic and unwinding ends have separate generatrices, that is to say different base and unwinding angles with respect to the axis of the coil. The application JP 10-218 489, although different application of a glass wire winding since a bobbin feeding cabling or braiding machines, shows such a form of coil and describes its method of obtaining . The construction of the reel is carried out according to four stages which correspond to four successive parts of the reel: the first part consists of the lower part of the bobbin and represents at most half the height of the winding, it is preferably well less than half of the winding, the angle of this tapered base relative to the axis of the bobbin being between 16 and 22 °. The second part is obtained by means of layers parallel to those of the first part and of identical length, but the thickness of the layers decreases due to an acceleration of the movement of the cusp points towards the top of the can. The third part, constructed in parallel layers but of different inclination from those deposited in the first and second parts, completely makes the unwinding cone whose final angle with respect to the axis of the can is lower than that of the cone basic. Finally, the fourth part aims to finish the main body of the coil in cylindrical form by quickly moving the low cusp point of the high cusp.

However, this method requires, on the one hand, four distinct winding steps, and on the other hand, the change of pitch inclination of the wire layers during these steps, which does not simplify its implementation.

In addition, this winding method generates an angle of construction of the first layers with respect to the axis of the coil which is too large for a winding application such as that desired, namely the winding of glass wire from a pathway. This large angle of construction induces large circumferential variations between the circumference of the base cone and the circumference obtained at the end of the first step of the process; gold, for a winding of glass wire whose stretching speed must be kept constant to keep the title of the constant wire, such variations in circumference impose substantial variations in the speed of the support of the coil both in acceleration and braking, which is difficult to achieve materially.

Furthermore, in this method, the guide element of the wire for its deposition consists of a guide eyelet which moves parallel to the axis of the support of the coil in rotation. However, this guide mode can not be envisaged for guiding a glass wire for winding, in particular a wire directly from a die. Indeed, in case of breakage of the filaments from the die, the recovery of winding would prove too complicated; it is too difficult after collecting the filaments to pass them again through the eyelet which has a closed circumference. It is also impossible with one eyelet to transfer the winding of the thread of one spool to another spool without having to break the thread, which hampers the optimization of the production times.

In addition, the eyelet has an opening for the passage of the wire much too large compared to the diameter of said wire to allow precise guidance of the deposition of the wire.

Document FR-A-1 376 392 also discloses a method of manufacturing a frustoconical coil which consists in depositing the layers of wire by complete overlap from one end to the other of the coil, the cones of end being thus constructed simultaneously.

Document CH-A-238 829 also discloses a frustoconical coil whose support is conical and non-cylindrical.

JP-A-404 209 167 discloses a frustoconical coil whose generatrices connecting the end cones are parallel to the longitudinal axis.

The object of the invention is therefore to obviate the abovementioned drawbacks and to provide a method for obtaining a frustoconical coil having good mechanical strength and easy unwinding, the winding being in a horizontal plane without requiring major modifications. of the conventional implementation device already existing.

According to the invention, the method of winding a wire according to superimposed layers on a cylindrical support of longitudinal axis X and fixed around a pin driven by a rotary movement about this longitudinal axis X, according to which, the wire is wound by scrolling on a wire guide which moves in a reciprocating movement parallel to the axis X of the support and is controlled so as to form a coil whose shape has two frustoconical ends, respectively called cone of base and winding cone, of respective generatrices which are inclined relative to the longitudinal axis X according to two distinct respective acute inclination angles and a frustoconical main body connecting the two basic cones and unwinding and whose two end sections constitute the two bases of the two respective cones with distinct diameters D1 and D2 respectively, is characterized in that it comprises two displacement rules of the wire guide, a first rule which makes it possible to form a part of the basic cone, the last layer of wire deposited according to this first rule up to the end of the unwinding cone, and a second rule that terminates said base cone started and concomitantly form the main body and the unwinding cone, the first layer of wire deposited according to the second rule being parallel to the last layer deposited according to the first rule.

• une position de départ (x_j) dont celle du premier mouvement est la position initiale (x₀) et celle des mouvements suivants est une position postérieure à la position de départ du mouvement précédent et toujours antérieure à la position finale (x_z), la position du dernier mouvement étant imposée selon la valeur du diamètre D1 désirée pour le cône de base à former,
• une position intermédiaire (x_i) de changement de sens du guide-fil, position qui est toujours située postérieurement à la position intermédiaire du mouvement précédent et située antérieurement à la position finale (x_z),
• une position d'arrivée (X_j+1) qui constitue la position de départ du mouvement suivant,

le dernier mouvement selon cette première règle n'effectuant pas de changement de sens depuis la dernière position intermédiaire qui constitue alors la position finale (x_z).According to one characteristic of the invention, the first rule of displacement of the wire guide consists in establishing reciprocating movements parallel to the axis of the support between an initial position (x ₀ ) and a final position (x _z). ) which respectively correspond, in projection perpendicular to the support, to each of the end sections of the coil, each reciprocating movement being defined by:

• a starting position (x _j ) of which that of the first movement is the initial position (x ₀ ) and that of the following movements is a position posterior to the starting position of the preceding movement and always anterior to the final position (x _z ), the position of the last movement being imposed according to the value of the desired diameter D1 for the base cone to be formed,
• an intermediate position (x _i ) of change of direction of the thread guide, position which is always situated after the intermediate position of the preceding movement and situated before the final position (x _z ),
• an arrival position (X _{j + 1} ) which constitutes the starting position of the next movement,

the last movement according to this first rule does not effect a change of direction since the last intermediate position which then constitutes the final position (x _z ).

The successive starting positions (x _j ) according to the first rule are separated by an equal distance (δ), and the successive intermediate positions (x _i ) of change of direction according to the first rule are defined according to the equation x _i = x ₀ + iΔ, where Δ is a constant which is a function of the slope to be given to the generatrix of the main body.

Note that throughout the description, the former and posterior qualifiers assigned to the term position are defined with respect to the positive direction of movement of the wire guide from the position x ₀ to the position x _z .

• une position de départ (x_k) dont celle du premier mouvement est la position finale (x_z) selon la première règle, et celle des mouvements suivants est une position antérieure à la position de départ du mouvement précédent,
• une position intermédiaire (x_m) de changement de sens du guide-fil dont celle du premier mouvement est la position d'arrivée qu'aurait dû prendre le guide-fil s'il avait changé de sens de déplacement à la position finale (x_z) selon la première règle, et
• une position d'arrivée (x_k+1) qui constitue la position de départ du mouvement suivant,

les positions de départ et d'arrivée d'un mouvement étant toujours antérieures à celles du mouvement précédent de manière que chaque mouvement soit raccourci en parcours.According to another characteristic, the second rule of displacement of the wire guide consists in making reciprocating movements parallel to the axis of the support, between an initial position which constitutes the final position (x _z ) of the wire guide. according to the first rule and a terminal position (x _t ) situated between the final position (x _z ) according to the first rule and imposed according to the value of the desired diameter D2 for the unwinding cone to be formed, and the starting position of the last displacement according to the first rule, each back and forth movement being defined by:

• a starting position (x _k ) of which that of the first movement is the final position (x _z ) according to the first rule, and that of the following movements is a position prior to the starting position of the preceding movement,
• an intermediate position (x _m ) of change of direction of the thread guide, of which the one of the first movement is the arrival position which the thread guide should have taken if it had changed direction of movement to the final position (x _z ) according to the first rule, and
• an arrival position (x _{k + 1} ) which constitutes the starting position of the next movement,

the starting and finishing positions of a movement being always earlier than those of the preceding movement so that each movement is shortened in course.

The successive starting positions (x _k ) according to the second rule are separated by an equal distance (δ '), and the successive intermediate positions (x _m ) of direction change according to the second rule are spaced by the same distance (δ ) that separating the successive starting positions (x _j ) according to the first rule.

According to another characteristic, the wire guide is moved in concomitance with the movement parallel to the X axis in a coplanar movement and perpendicular to the X axis so that the resulting movement is parallel to the generatrix of the main body. Thus, the thrown length remains constant for a wire deposit as accurate as possible.

According to an advantageous characteristic, the wound wire has a corrugation so that the crossing angle between two turns is between 0.5 ° and 6 °.

The advantage of creating a ripple on the wire makes it possible to optimize the crossing angle in order to reduce the risk of forming rings during unwinding.

This method is advantageously used for winding glass wire directly from a die.

• la figure 1 est une vue en coupe longitudinale de la bobine selon l'invention sur son support d'enroulement;
• les figures 1a à 1c illustrent plusieurs exemples de bobines tronconiques selon l'invention; La figure 1d n'est pas couverte par les revendications
• la figure 2 illustre deux spires de fil entrecroisées;
• la figure 3 représente une vue schématique d'une installation permettant la mise en oeuvre du procédé selon l'invention;
• la figure 4 montre une vue de profil d'un guide-fil constitué par une came au travers de laquelle défile le fil;
• la figure 5 représente différentes positions prises par le guide-fil sur son axe de déplacement parallèle au support en combinaison avec une vue en coupe partielle longitudinale de la bobine.

Other features and advantages of the invention will appear on reading the description which follows, with reference to the drawings in which:

• Figure 1 is a longitudinal sectional view of the coil according to the invention on its winding support;
• FIGS. 1a to 1c illustrate several examples of frustoconical coils according to the invention; Figure 1d is not covered by the claims
• Figure 2 illustrates two interwoven wire turns;
• FIG. 3 represents a schematic view of an installation for implementing the method according to the invention;
• Figure 4 shows a side view of a wire guide constituted by a cam through which the wire runs;
• Figure 5 shows different positions taken by the wire guide on its axis of movement parallel to the support in combination with a longitudinal partial sectional view of the coil.

FIG. 1 shows a frustoconical coil 10 made according to the invention, obtained by winding a wire around a cylindrical support 20 of longitudinal axis X and devoid of any flank at its ends. The wound wire is an example of the glass wire.

The coil 10 comprises a frustoconical coil body 11 and two truncated cones 12 and 13 respectively at the two longitudinal and opposite ends of the coil, on each side of the coil body 11.

The coil body 11 has a base 11a of diameter D1 and an end section 11b of diameter D2 less than the diameter D1, the generator L1 of the frustoconical body 11 thus being inclined with respect to the axis X at an angle θ.

The end cone frustum 12 formed firstly during winding will be named after the base cone. It has a base 12a constituted by the base 11a of the coil body 11 of diameter D1, and a termination 12b whose diameter corresponds to that of the support 20. The truncated cone 12 comprises a generator L2 whose slope forms with the surface of the support 20, or with the axis X, an acute angle α.

The second end cone frustum 13 will be called the unwinding cone because its section being always smaller than that of the base cone, unwinding will be made from it to facilitate the detachment of the wire from the reel. The unwinding cone 13 has a base 13a constituted by the end section 11b of the coil body 11 of diameter D2, and a termination 13b whose diameter corresponds to that of the support 20. The conical truncum 13 comprises a generator L3 whose slope form with the surface of the support 20, or with the axis X, an acute angle β whose value is independent of that of the angle α.

The generatrices L2 and L3 of the base cones 12 and of the unwinding 13 are thus inclined with respect to the axis X in opposite directions to be connected to the generator L1 of the frustoconical body 11.

The spool 10 thus formed of three truncated cones makes it possible to reinforce its mechanical strength as well as to improve the quality of the unwinding and thus to preserve at best the properties of the yarn which are in particular its integrity and its tensile strength. This finished product also has great ease of use for the subsequent processing of the fiberglass.

The base cone 12 is the place where you can accumulate the most thread on the winding, helping to increase the weight of it. Thus, the angle α may be as close as possible to the perpendicular to the X axis to a limit that defines the occurrence of landslides winding or transport. Advantageously, the angle α will be between 40 ° and 75 ° with respect to the X axis.

The angle β of the unwinding cone 13 mainly affects the behavior of the turns at the point of change of direction of the wire guide, also called cusp point, the angle β will preferably have a value of between 30 ° and 60 ° by relative to the X axis.

The values of these angles are also chosen according to the quality of the size which gives the slipperiness to the surface of the fibers.

FIGS. 1a to 1c illustrate the combination of the different values of the angles α and β according to several coil lengths. The length of the coil between the terminations 12b and 13b can vary between 150mm and 500mm, and preferably between 180mm and 400mm. Figure 1d is not covered by the claims

The ease of unwinding that already provides the frustoconical shape of the coil is embodied by the characteristics of the wound wire.

Thus, as illustrated in FIG. 2, the wound wire 50 comprises turns 52, of which two adjacent ones are intersecting at a crossing angle γ, and has a corrugation 51. The obtaining of these characteristics will be explained later.

The winding method according to the invention, making it possible to manufacture a coil such as that described above, can be implemented in the context of an installation which is illustrated schematically in FIG.

The installation comprises a die 30 supplied with glass by a power source not shown.

The die can be fed from cold glass, obtained and stored in the form of beads in a hopper disposed above the die, the die then being heated to remelt the glass, or can be directly fed from molten glass, the die being also heated to maintain the glass at a temperature sufficient to achieve the viscosity suitable for drawing as continuous filaments.

The molten glass flows vertically from a multiplicity of orifices, such as the nipples 31. and is immediately stretched into a multiplicity of filaments 40. here assembled in a single ply 41.

This sheet 41 comes into contact with a coating device 32 intended to coat each filament with a size of aqueous or anhydrous type. The device 32 may consist of a tank continuously fed by a sizing bath and a rotating roller whose lower part is constantly immersed in the bath. This roll is permanently covered with a film of size which is taken in passing by the filaments 40 sliding on its surface.

The sheet 41 then converges to an assembly device where the various filaments are joined to give birth to the wire 50. The assembly device may be constituted by a simple grooved pulley or a plate provided with a notch.

The wire 50 leaving the assembly device penetrates into a wire guide 34, such as a cam, to be wound around the support 20 arranged in a plane horizontal with respect to the vertical arrival of the wire towards the wire guide . The yarn is thus wound directly from the die without intermediate step such that the manufacture of a prior cake.

The support 20 is fixed on a pin 21 which is moved by a rotary movement. The support 20 is advantageously hollow, its internal shape conforming to the external shape of the spindle 21, and its internal section being substantially larger than that of the spindle for being threaded and held tight around it by an expansion device. the pin not visible.

Pin 21 is rotated by a motor 22 whose drive speed is adjustable.

The wire guide 34 is reciprocated M horizontal and parallel to the longitudinal axis X of the support, and preferably, a movement back and forth horizontally and perpendicular to the X axis and made in concomitance with the movement M as it will be explained later

The wire guide 34 is fixed to the end of a movable arm 35 directed by an electronic drive device 36.

A controller 37 such as a programmable logic controller is provided to control the movement of the movable arm 35 and the speed of movement of the wire guide 34 as well as the speed of rotation of the brush 21.

The rotational speed of the spindle 21 and the linear displacement speed of the thread guide 34 parallel to the axis X may vary. The implementation of these speed variations can be performed optionally according to the desired quality of the wire after winding. The rotational speed of the spindle is imposed according to the flow rate of the die and the linear density of the desired yarn. As for the speed of the wire guide, it influences the quality of the wire feed.

It is known that the linear density of the wire corresponds to the ratio of the flow rate of the die to the speed of drawing of the wire. it is always desirable that the linear density be constant so that the wound wire has a uniform quality of mechanical strength. However, the section variation of the coil 10 necessarily causes a variation in the drawing speed. So that the linear density is constant, it is necessary to maintain constant drawing speed in the assumption that the flow of the die remains constant The wire guide has no effect on the drawing of the wire, the drawing speed depends only on the speed of rotation of the spindle. The rotational speed of the spindle 21, and therefore of the support 20, is thus varied so that the thread constantly encounters a surface whose peripheral speed is substantially constant.

The constancy of the linear density of the yarn is controlled by the programming of the drawing speed imposed by the speed of rotation of the spindle 21 and according to the position of the thread guide corresponding to a given section of the spool.

Thus, by varying the speed of rotation of the spindle adequately according to the section of the coil, it is possible to keep constant the linear density of the wire.

On the other hand, if no variation is imposed, the linear density of the wire varies around a median value, the amplitude of the variation depending on the angle θ of the generator L1 with the axis X.

As for the speed of movement of the wire guide, it can also vary. By varying this speed, the angle θ of the generator L1 with the X axis is retained during the winding, which makes it possible to make the reeling properties constant regardless of the position of the wire.

On the other hand, if no variation is imposed, the angle θ decreases during winding, which can cause a drop in the quality of the unwinding outside the coil.

The guide wire 34 is, as we have already indicated, preferably constituted by a cam as illustrated in FIG. 4.

This cam comprises a continuous groove 34a in which the wire 50 scrolls. The groove is generally helical and has at least two sections 34b and 34c whose respective slopes are reversed.

The cam has a pitch p which corresponds to the width, measured parallel to the axis of rotation, between the two points of tangential passage of the wire on a section for which the curvature of the wire is effected. This step determines the amplitude given to the waving of the wire.

The helical shape of the groove makes it possible to give the wire during the winding an undulation whose number of sinusoids on a turn and their width are a function of the pitch p of the cam and the speed of rotation thereof.

The periodicity of the ripple, that is to say the number of sinusoids, acts on the number of crossings of the wire when several layers of turns are superimposed. The proportion of the number of crossings must be advantageously balanced. In fact, the greater the proportion of crossings, the better the mechanical strength of the bobbin and the winding ability, but in counterpart, at equivalent weight of wire, the bulk of the coil increases, which is penalizing for the transport and the length of yarn available for weaving operations such as warping.

Thus, the speed of rotation of the cam is adapted to establish an adequate periodicity of the corrugation. This speed can be defined with respect to the drawing speed of the wire, it varies between -10% and + 30% of the value of the drawing speed, and preferably between the value of the drawing speed and + 15% of this value.

Not only the crossings avoid a slip of a turn of one of the layers on the turns of a lower layer, thus achieving a better mechanical strength of the coil once formed and facilitating the unwinding of the wire, but the angle of crossing γ also contributes to the accuracy of formation of the cone, and prevents the last turn of the coil from being free.

In addition, the crossing angle and the corrugation establishing the length of free turn formed in the winding, it should be that this length is short to avoid the risk of tearing of the wire during the release of the turns around the cone unwinding when friction phenomena appear such as that of the double-balloon.

The average value of the angle γ depends on the speed of movement of the wire guide 34 parallel to the axis X and the speed of rotation of the pin 21.

As for the real value of the angle γ at each crossing point, it also depends on the combination of the displacement of the wire guide and the position of the wire induced by the position of the wire guide at the time of depositing the wire on the winding surface.

A suitable average value of the crossing angle γ is preferably between 0.5 ° and 6 °.

The winding method according to the invention is based on the back-and-forth movement imposed on the thread guide 34. It is divided into two stages according to two rules respective displacement, the first creating a portion of the generatrix L2 of the base cone 12, and the second terminating the generator L2 and simultaneously achieving the formation of generators L1 and L3, respectively, of the body 11 and the unwinding cone 13.

The first step is to move the wire guide between an initial position x ₀ which corresponds to an end position of the coil for which is wound the first turn of the coil, that is to say to the position of the terminal 12b of the base cone 12, and a final position x _z which corresponds to the position of the opposite end of the coil, that is to say of the base 13b of the unwinding cone 13.

Between the positions x ₀ and x _z , the wire guide 34 performs several reciprocating moves _{i i} each of which comprises a path going to _i in the direction of the position x _z and a return path R _i towards the initial position x ₀ .

The first displacement d ₁ comprises the going to ₁ and the return R ₁ , the going to ₁ beginning of the initial position x ₀ and ending at the position x ₁ such that x ₁ = x ₀ + Δ, and the return path R ₁ starting at the position x ₁ and ending at the position x ₀ + δ, the guide wire not returning to the initial position x ₀ .

The second displacement d ₂ comprises the going to ₂ and the return R ₂ , the going to ₂ starting at the last position of the wire guide x ₀ + δ, and stopping at the position x ₂ posterior to the position x ₁ such that x ₂ = x ₀ + 2Δ, and the return path R ₁ starting at the position x ₂ to stop at the position x ₀ + 2δ.

The penultimate displacement d _{z-1 will} comprise the go to _z-1 and the return R _z-1 , the go to _z-1 beginning of the final position x ₀ + (z-2) δ of the return of the displacement preceding, and stopping at the position x _z-1 such that x _z-1 = x ₀ + (z-1) Δ, and the return path R _z-1 starting at the position x _z-1 to stop at the position x ₀ + (z-1) δ.

The last displacement d _{z will} only include a go to _z and no return, the start a _z beginning of the final position x ₀ + (z-1) δ of the return of the previous displacement, and stopping at the final position x _z such that x _z = x ₀ + zΔ. The starting position x ₀ + (z-1) δ of the last displacement is defined according to the desired value of the diameter D1 of the base cone.

• une position de départ x_j=x₀+jδ, avec j variant de 0 à (z-1), z entier non nul,
• une position intermédiaire de changement de sens, ou encore de retour en sens inverse, x_i=x₀+iΔ, avec i variant de 0 à z, z entier non nul
• et une position d'arrivée constituant la prochaine position de départ x_j+1=x_j +δ = x₀+(j+1)δ,

le dernier déplacement de cette première étape correspondant à un trajet jusqu'à la position x_z sans retour en sens inverse.Therefore, the wire guide 34 performs between the position x ₀ and the position x _z reciprocating movements which each define:

• a starting position x _j = x ₀ + jδ, with j varying from 0 to (z-1), z being a non-zero integer,
• an intermediate position of change of direction, or of return in opposite direction, x _i = x ₀ + iΔ, with i varying from 0 to z, z nonzero integer
• and an arrival position constituting the next starting position x _{j + 1} = x _j + δ = x ₀ + (j + 1) δ,

the last displacement of this first step corresponding to a path to the position x _z without return in the opposite direction.

The fact of not returning to the starting position of the preceding displacement makes it possible to construct a portion of the generator L2 of the base cone 12.

The value of δ depends on the angles α and β that we want to assign to the basic and unwinding cones.

The value of Δ, a positive constant, depends on the slope that one wants to give to the generator L1 and is therefore a function of the value of δ. The smaller the value of Δ, the larger the angle θ of the generator L1 with the X axis. This Δ value is chosen so that the angle θ is between 0.5 ° and 5 °, and preferably between 0.75 ° and 3 °.

For the second step, the wire guide 34 moves back and forth between the position x _z occupied at the end of the first step and a terminal position x _t for which the desired diameter D 2 of the base 13a is reached. the unwinding cone.

Each movement comprises a forward path starting at a position x _k and a return path beginning at an intermediate position of change of direction x _m and stopping at an arrival position x _k-1 , the guide wire always stopping to change direction to a position prior to the occupied position at the start or finish of the previous trip. The outward and return journeys therefore decrease in distance in both directions.

Thus, the first displacement comprises a go starting at the position x _k = x _z and arriving at the position x ₀ + (z-1) δ + δ, or else x ₀ + z _δ , where x ₀ + (z-1 ) δ corresponds to the starting position of the last displacement of the first step, and a return starting at the position x _m = x ₀ + zδ and ending at the position x _{k + 1} = x _z -δ '.

At the next displacement, the go starts at the position x _z -δ ', arrives at the intermediate position of change of direction x ₀ + zδ + δ and returns to the position x _z -2δ'.

As the return and return paths of the wire guide, the coil body 11 and the unwinding cone 13 are formed. The last movement of the wire guide 34 is programmed so that it stops at the position x _t , which corresponds to the position x _z -tδ ', for which the desired value of the diameter D2 is reached.

The value of δ 'depends on the angles α and β that we want to assign to the basic and unwinding cones, δ' being generally greater than δ.

• une position de départ x_k=x_z-nδ', avec n variant de 0 à t, t entier non nul,
• une position intermédiaire de changement de sens x_m=(x₀+zδ)+pδ, avec p variant de 0 à (t-1),
• et une position d'arrivée constituant la prochaine position de départ x_k+1=x_k-δ'.

The displacements of the second rule can therefore be defined by:

• a starting position x _k = x _z -nδ ', with n varying from 0 to t, t being non-zero integer,
• an intermediate position changing direction x _m = (x ₀ + zδ) + pδ, with p varying from 0 to (t-1),
• and an arrival position constituting the next starting position x _{k + 1} = x _k-δ '.

We have explained that the wire guide is driven in a movement M parallel to the axis X. It turns out that this movement in this direction can lead to some disadvantages that we will explain below and that can be nonetheless resolved in implementing optional features of the method according to the desired winding quality.

The section variation of the coil, in particular in the direction of the decrease at the level of the body 11 and of the unwinding cone 13, generates, as the wire guide moves at a constant speed, as and when the the section a very significant increase in the thickness of the coil, which is reflected at the end of winding by a decrease in the angle φ between generators L1 and L3 may be greater than 1 °. Indeed, assuming that the die delivers a constant amount of glass per unit of time while the wire guide moves at a constant speed, an identical mass of glass per unit time is then deposited on the support; but the section of the coil is not uniform, a larger amount of wire is deposited as the section decreases.

In addition, when decreasing section, the distance separating the wire guide from the surface of the coil, usually named length thrown length, increases which leads to a growing inaccuracy of the deposition of the wire making on the one hand the winding less stable. in particular on the side of the unwinding cone, and secondly, disadvantageous the quality of the unwinding.

To ensure a constant precision of the deposition of the wire, it is more advantageous during the implementation of the method to simultaneously perform the movement M parallel to the X axis a movement perpendicular to the X axis towards the coil in formation to compensate for the variation in discarded length, the sum of the two displacements corresponding to a displacement parallel to the generator L1 so that the thrown length remains constant.

This movement perpendicular to the axis X in the same horizontal plane as that of the movement M is effected by the control of the movable arm 35.

Displacements are carried out thanks to the movable arm 35 whose movement is controlled by the electronic device 36. Alternatively, it would be possible to use mechanical means constituted by a guide rail fixed parallel to the future generator L1 and on which the wire guide 34.

Claims (19)

1. Method of winding a yarn in superposed layers onto a cylindrical support (20) of longitudinal axis (X) and fastened around a spindle (21) driven in a rotational movement, in which the yarn is wound by running over a yarn guide (34) which moves in a traverse motion (M) parallel to the axis (X) of the support and is controlled so as to form a bobbin whose shape has two frustoconical ends (12, 13). called the base cone and the unwind cone respectively, having respective generatrices (L2, L3) which are inclined with respect to the axis (X) at acute angles (α, β) respectively, and a main body (11) which joins the two ends and has a frustoconical shape with a generatrix (L1) and the two end sections (11a, 11b) of which form the two bases (12a, 13a) of the respective two cones (12, 13) and have different diameters, D1 and D2 respectively, characterized in that it comprises two rules governing the movement of the yarn guide, a first rule which is used to form part of the base cone (12), the last layer of yarn deposited according to this first rule going as far as the end (13b) of the unwind cone, and a second rule which is used to terminate the said base cone (12) that has been started and, concomitantly, to form the main body (11) and the unwind cone (13), the first layer of yarn deposited according to the second rule being parallel to the last layer deposited according to the first rule.
2. Winding method according to Claim 1, characterized in that the first rule governing the movement of the yarn guide consists in establishing traverse motions parallel to the x axis between an initial position (x_o) and a final position (x_z) which correspond, in projection perpendicular to the support (20), to each of the end sections (12b, 13b) of the bobbin respectively, each traverse motion being defined by:

   - a starting position (x_j) , of which that one for the first movement is the initial position (x₀) and that one for the following movements is a position to the rear of the starting position for the previous movement and always to the front of the final position (x_z), the position for the last movement being dictated by the value of the diameter D1 desired for the base of the base cone (12) to be formed,

   - an intermediate position (x_i) for reversal of the yarn guide, which position always lies to the rear of the intermediate position for the previous movement and lies to the front of the final position (x_z), and

   - an ending position (x_j+1) which constitutes the starting position for the following movement, the last movement according to this first rule not causing a reversal since the last intermediate position which then corresponds to the final position (x_z).
3. Winding method according to Claim 2, characterized in that the second rule governing the movement of the yarn guide consists in executing traverse motions parallel to the X axis, between an initial position which constitutes the final position (x_z) of the yarn guide according to the first rule and a terminal position (x_t) which lies between the final position (x_z) according to the first rule, and which is dictated by the value of the diameter D2 desired for the base of the unwind cone (13) to be formed, and the starting position for the last movement according to the first rule, each traverse motion being defined by:

   - a starting position (x_k), of which that one for the first movement is the final position (x_z) according to the first rule and that one for the following movements is a position to the rear of the starting position for the previous movement,

   - an intermediate position (x_m) for reversal of the yarn guide, of which that one for the first movement is the ending position that the yarn guide ought to have assumed if it had reversed the movement at the final position (x_z) according to the first rule, and

   - an ending position (x_k+1) which constitutes the starting position for the following movement,

   - the starting and ending positions for a movement always being to the front of those for the previous movement so that each movement is shortened in terms of travel.
4. Method according to Claim 2, characterized in that the successive starting positions (x_j) according to the first rule are separated by an equal distance (δ) .
5. Method according to Claim 2, characterized in that the successive intermediate reversal positions (x_i) according to the first rule are defined by the equation x_i =x₀ + iΔ, where Δ is a positive constant which depends on the slope to be given to the generatrix (L1) of the main body (11), and i varies from 0 to Z, where Z is a non-zero integer.
6. Method according to Claim 3, characterized in that the successive starting positions (x_k) according to the second rule are separated by an equal distance (δ').
7. Method according to Claim 3, characterized in that the successive intermediate reversal positions (x_m) according to the second rule are spaced apart by the same distance (δ) as that separating the successive starting positions (x_j) according to the first rule.
8. Method according to any one of Claims 1 to 7, characterized in that the yarn guide (34) is moved concomitantly with the motion (M) parallel to the axis (X) in a coplanar motion (N) perpendicular to the axis (X) so that the resulting motion is parallel to the generatrix (L1) of the main body (11).
9. Method according to Claim 8, characterized in that the motions parallel (M) and perpendicular (N) to the axis (X) of the yarn guide (34) are produced by an electronic drive device (36).
10. Method according to Claim 8, characterized in that the yarn guide (34) is moved by running along mechanical guiding means placed parallel to the generatrix (L1) of the main body (11) being formed.
11. Method according to any one of Claims 1 to 10, for which the yarn guide (34) consists of a cam, characterized in that the speed of rotation of the cam can be varied.
12. Method according to any one of Claims 1 to 11, characterized in that the speed of rotation of the spindle (21) can be varied.
13. Method according to one of Claims 1 to 7, characterized in that the speed of movement of the yarn guide parallel to the axis (X) can be varied.
14. Application of the method, as defined by any one of Claims 1 to 13, to the direct winding of a continuous yarn which is obtained by collecting a multiplicity of glass filaments formed from streams of molten glass, emanating from the orifices of a bushing, and which runs along a yarn guide.
15. Frustoconical bobbin obtained by the method according to any one of Claims 1 to 13, characterized in that the angle of inclination (α) of the so-called base cone (12) is between 40° and 75°.
16. Frustoconical bobbin obtained by the method according to any one of Claims 1 to 13, characterized in that the angle of inclination (β) of the unwind cone (13) is between 30° and 60°.
17. Frustoconical bobbin according to Claim 15 or 16, characterized in that the yarn has a waviness (52) so that two coils belonging with two superposed layers respectively intersect at a crossover angle (γ).
18. Frustoconical bobbin according to Claim 17, characterized in that the crossover angle (γ) is between 0.5° and 6°.
19. Frustoconical bobbin according to any one of Claims 15 to 18, characterized in that it has a length, measured between the two end bases (12b, 13b) of the respective base and unwind cones, which is between 150 mm and 500 mm.

Images