EP0299553B1 - Thread clip - Google Patents

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Publication number
EP0299553B1
EP0299553B1 EP19880201286 EP88201286A EP0299553B1 EP 0299553 B1 EP0299553 B1 EP 0299553B1 EP 19880201286 EP19880201286 EP 19880201286 EP 88201286 A EP88201286 A EP 88201286A EP 0299553 B1 EP0299553 B1 EP 0299553B1
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EP
European Patent Office
Prior art keywords
piezoelectric
clamp
clip according
thread clip
crystals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19880201286
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German (de)
French (fr)
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EP0299553A1 (en
Inventor
Jozef Verhulst
Frank Ampe
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Picanol NV
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Picanol NV
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Publication of EP0299553A1 publication Critical patent/EP0299553A1/en
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Publication of EP0299553B1 publication Critical patent/EP0299553B1/en
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    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
    • D03D47/34—Handling the weft between bulk storage and weft-inserting means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H59/00—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators
    • B65H59/10—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators by devices acting on running material and not associated with supply or take-up devices
    • B65H59/20—Co-operating surfaces mounted for relative movement
    • B65H59/22—Co-operating surfaces mounted for relative movement and arranged to apply pressure to material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2555/00—Actuating means
    • B65H2555/10—Actuating means linear
    • B65H2555/14—Actuating means linear piezoelectric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/30—Handled filamentary material
    • B65H2701/31—Textiles threads or artificial strands of filaments

Definitions

  • the present invention relates to a wire clamp, and more particularly to a wire clamp for use on weaving machines or other machines processing spun yarn.
  • wire clamp or clamp we mean here any device whose operation ensures the clamping of a wire between two faces, either to brake a moving wire, that is to say to slow the movement or for the '' bring to a halt, either to simply grab a stationary wire presented between the two faces of the clamp.
  • the present invention relates to wire clamps whose movement is ensured by the reverse piezoelectric effect.
  • the present invention relates to a wire clamp which does not have the disadvantages mentioned.
  • the invention provides a clamp having the characteristic of comprising a drive mechanism consisting essentially of at least one piezoelectric element with reverse action.
  • a reverse action piezoelectric element consists of one or more piezoelectric crystals provided with the required electrical connections, the application of an appropriate electrical voltage conventionally making it possible to obtain a deformation of the expanding piezoelectric crystal. or in contraction. This deformation is used to close or open the clamp.
  • the advantages of the pliers for piezoelectric wire according to the invention consist in the small amount of electrical energy required for its operation, in its extremely rapid reaction time, in the fact that its clamping force is completely controllable, in the relatively inexpensive nature of its production and, finally, in its small size when mounted in a weaving machine.
  • a thread clamp according to the invention in addition to its use as a weft clamp, can be used at other points of a weaving machine and in particular at all points requiring clamps, operation requires very precise control.
  • the piezoelectric element with reverse action is formed by a piezoelectric crystal 1 fixed permanently on a support 3 at one of its ends 2, and whose l other end 4, free, forms a clamping element or clamping face which can interact with another element or clamping face 5, fixed permanently to the support 3.
  • the clamping face 4 can be provided with a wear-resistant jaw 6 made for example from a ceramic material.
  • the clamping face 5 can also be provided with a ceramic or other coating.
  • the assembly of this device may include layers of elastic material 7 intended to absorb shocks or vibrations and interposed for example, as illustrated in FIGS. 1 and 2, between the crystal 1 and the wear-resistant jaw 6 and / or between the clamping face 5 and the part of the support 3 on which it rests.
  • the piezoelectric crystal 1 is provided with electrical connections 8 to which an appropriate electrical voltage V can be applied, for example using an electrical supply 9 as illustrated diagrammatically in FIG. 1.
  • FIGS. 1 and 2 The operation of the wire clamp is illustrated in FIGS. 1 and 2.
  • the applied voltage V has a given value V1 and the clamp does not exert any clamping or braking force, so that the wire 10 passes freely between the clamping faces.
  • the applied voltage has a value V2 lower than V1, causing an expansion of the crystal proportional to the drop in voltage, so that the wire 10 is wedged between the jaw 6 and the clamping face 5.
  • the clamping force will increase in proportion to any greater drop in voltage V.
  • Figures 3 and 4 show another alternative embodiment, using a curved piezoelectric crystal 11 whose magnitude of the curvature is a function of the magnitude of the voltage V applied.
  • the piezoelectric crystal 11 is fixed permanently to one of its ends 12 and provided, at the other end 13, with a clamping face 4 formed by a jaw 6 similar to that of the variant embodiment illustrated in FIGS. 1 and 2.
  • This jaw can interact with a clamping element or fixed clamping face 5.
  • the end 12, fixed permanently, is provided with the required electrical connections 8.
  • Figures 5 and 6 illustrate, for an exemplary embodiment, the relationship between the speed of the voltage V applied to the electrical connections 8 and the corresponding clamping force F.
  • the voltage V is reduced so that the clamp begins to exert a certain clamping force F1 on the wire placed in the clamp.
  • a higher clamping force F2 can be achieved by further reducing the applied voltage, as illustrated in phase C.
  • FIGS 7 to 9 illustrate another embodiment which uses two piezoelectric crystals 14 and 15 arranged so as to face each other. Their distant ends 16 and 17 are fixed permanently, while their close ends 18 and 19, provided with wear-resistant jaws, are placed opposite.
  • This last variant offers the advantage of providing, on the one hand, an adjustable clamping force _ two values it is true _ when only one tension is applied, and on the other hand, a relatively large passage for the wire 10 when the two crystals 14 and 15 are energized at the same time.
  • such a double action clamp may also be produced by using two curved piezoelectric crystals 11 of the type mentioned above.
  • the piezoelectric elements 11 or 14-15 do not necessarily have to be mounted opposite. They can, for example, be placed one on the other in a series arrangement, so to speak, in which case they will interact with a clamping face permanently fixed.
  • Such a series connection could also consist of several piezoelectric crystals, the application of a single voltage value V then making it possible to obtain a clamping force adjustable in several steps.
  • these variant embodiments may also include a layer of damping material 7.
  • FIG. 10 shows an assembly of a weft thread driving mechanism for weaving machines, using four thread clamps 20 to 23. Furthermore, this weft driving mechanism essentially provides a reel holder 24, a supply device 25 formed by reel rollers 26 and a cylindrical tube 27 in which the weft thread 10 is stored in spiral form, preferably a main blower 28 and a comb 29 in a U shape.
  • the first clamp 20, placed at the outlet of the cylindrical tube 25, has the function of blocking at the required moments the wire taken in the tube.
  • a piezoelectric clamp 20 proves to be particularly advantageous on weft yarn supply devices of the type in which the weft yarn 10, as illustrated in FIG. 20, is stored in spiral form in a cylindrical tube 27 and more generally on any supply device in which the length of the pick is not directly determined by the shape of the supplier.
  • the exact determination of the pick to be inserted requires precise adjustment of the clamp 20 acting as a weft insertion clamp. This precision concerns both the opening and closing times, the opening and closing speeds and the dosage of the clamping force.
  • a clamp for piezoelectric wire according to the invention makes it possible to meet these requirements in a much more rigorous manner than conventional clamps.
  • the operation of the clamp 20 largely determines the operation of the entire weft insertion mechanism.
  • the clamp 20 When the clamp 20 is closed, a certain amount of wire is blown into the cylindrical tube 25 where it accumulates by depositing in a spiral along the inner wall of the tube.
  • the weft thread At the opening of the clamp 20, the weft thread is released; at the end of the insertion, the complete closure of the clamp 20, with the application of a high clamping force, causes the weft thread 10 to be blocked when its free end reaches the end of the crowd.
  • the clamp 20 As the clamp 20 is caused to abruptly close, it will preferably be provided with a layer of damping material 7.
  • the second clamp 21 is placed at the end of the crowd. It is known that when a weft thread is braked by the clamp 20 when this thread reaches the end of the crowd, its force of inertia imposes an elastic elongation followed by a contraction, resulting in a recoil effect of the end of the wire 10. To avoid this recoil and, consequently, to prevent the formation of loops in the fabric, the wire 10 is conventionally straightened using a pneumatic weft guide which intercepts the front end of the wire weft. Interception and straightening of the wire could however also be carried out by pliers offering a sufficiently short reaction time to grasp the wire within an adequate time on receipt of a command signal.
  • a piezoelectric clamp 21 is particularly suitable for the application which has just been described. Since the clamp 21 must be capable, in the open position, of intercepting the weft thread inserted in the crowd, it should preferably have a relatively wide passage in the open position. It is therefore advisable to use for this application a wire clamp of the type illustrated in Figure 7 or, a clamp incorporating one or more piezoelectric crystals connected in series. The presence of the wire 10 will preferably be detected by the piezoelectric crystals of the clamp 21 itself, so as to generate the control signal mentioned above.
  • a piezoelectric clamp can be used to hold the weft thread on the insertion side.
  • a high clamping force and a relatively large passage for the wire 10 are two very important factors.
  • the third clamp 22 straightens the wire 10 in front of the unwinding rollers 26.
  • the clamp 22 is formed by two curved crystals 11 which can work in interaction and capable of clamping the wire 10 between the jaws 6.
  • the fourth clamp 23, mounted just in front of the main blower 28, can exert an adjustable pressing force on a wire, so that the wire 10 can be braked gradually when it reaches the end of the crowd, so as to avoid overvoltages and reduce the risk of breakage of the weft thread.
  • the assembly given in FIG. 10 illustrates a whole series of possible applications of the clamp for piezoelectric wire according to the invention.
  • the first clamp 20 has the function of blocking a moving wire.
  • the second clamp 21 is used only to grip a wire.
  • the third and fourth clamps, 22 and 23 respectively, have a braking function and exert only a reduced clamping force on the moving wire 10.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Wire Bonding (AREA)

Description

La présente invention à trait à une pince pour fil, et plus particulièrement à une pince pour fil destinée à être utilisée sur des machines à tisser ou d'autres machines traitant du fil filé. Par pince pour fil ou pince, il faut entendre ici tout dispositif dont le fonctionnement assure le serrage d'un fil entre deux faces, soit pour freiner un fil en mouvement, c'est-à-dire pour en ralentir le mouvement ou pour l'amener à l'arrêt, soit pour saisir simplement un fil immobile présenté entre les deux faces de la pince. En particulier, la présente invention concerne une pince pour fil dont le mouvement est assuré par l'effet piézo-électrique inverse.The present invention relates to a wire clamp, and more particularly to a wire clamp for use on weaving machines or other machines processing spun yarn. By wire clamp or clamp, we mean here any device whose operation ensures the clamping of a wire between two faces, either to brake a moving wire, that is to say to slow the movement or for the '' bring to a halt, either to simply grab a stationary wire presented between the two faces of the clamp. In particular, the present invention relates to wire clamps whose movement is ensured by the reverse piezoelectric effect.

Pour assurer l'entraînement ou la commande d'une pince destinée, par exemple, au freinage d'un fil de trame sur une machine à tisser pneumatique, on recourt classiquement à des systèmes mécaniques dont le mécanisme repose principalement sur l'utilisation de cames et/ou de ressorts. Ces systèmes mécaniques présentent plusieurs inconvénients. En effet, la modification des temps d'ouverture et de fermeture, ou encore la modification de la force de pression de la pince, nécessite un réglage long et difficile de la partie mécanique de la commande de la pince. De même, la modification de la force de pression et/ou celle de la vitesse d'ouverture et de fermeture requiert généralement l'installation d'un autre ressort et/ou d'une came ayant un profil différent.To ensure the driving or the control of a clamp intended, for example, for braking a weft thread on a pneumatic weaving machine, use is conventionally made of mechanical systems whose mechanism relies mainly on the use of cams and / or springs. These mechanical systems have several drawbacks. Indeed, the modification of the opening and closing times, or even the modification of the force of pressure of the clamp, requires a long and difficult adjustment of the mechanical part of the control of the clamp. Likewise, the modification of the pressure force and / or that of the opening and closing speed generally requires the installation of another spring and / or of a cam having a different profile.

Un autre désavantage important des systèmes mécaniques réside dans le fait que leur fiabilité laisse à désirer à des cadences machine très élevées. De plus, les tissages faisant intervenir plusieurs couleurs ou plusieurs types de fils nécessitent des mécanismes complexes. Comme au tissage à plusieurs couleurs, la commande des différentes pinces peut être subordonnée au cycle de tissage, on conçoit aisément qu'après une interruption du fonctionnement de la machine à tisser, par exemple suite à l'action d'un dispositif tel qu'un rechercheur de pas, il faut à chaque fois s'assurer de la bonne synchronisation entre commande des pinces et cycle de tissage.Another major disadvantage of mechanical systems is that their reliability leaves something to be desired at very high machine speeds. In addition, weaving involving several colors or several types of thread requires complex mechanisms. As with multi-color weaving, the control of the different pliers can be subordinated to the weaving cycle, it is easily understood that after an interruption of the operation of the weaving machine, for example following the action of a device such as a step finder, it is necessary to ensure each time the good synchronization between control of the pliers and weaving cycle.

On sait d'autre part que la commande d'une pince pour fil de trame peut être assurée par des dispositifs électromagnétiques. Ces pinces électromagnétiques présentent toutefois l'inconvénient de nécessiter une puissance électrique élevée pour offrir des temps de réaction appropriés lors des tissages à grande cadence. Dans la plupart des cas, cela se traduit par une surexcitation des électro-aimants de commande.We also know that the control of a weft thread clamp can be ensured by electromagnetic devices. These electromagnetic clamps, however, have the disadvantage of requiring a high electrical power to offer appropriate reaction times during weaving at high speed. In most cases, this results in overexcitation of the control electromagnets.

Un autre désavantage des dispositifs que l'on vient d'évoquer réside dans le fait que les moments d'ouverture et de fermeture, de même que les vitesses d'ouverture et de fermeture, sont caractérisés par une très grande dispersion, de sorte qu'il n'est pas toujours possible d'obtenir un fonctionnement correct à des cadences de tissage élevées.Another disadvantage of the devices which we have just mentioned resides in the fact that the opening and closing moments, as well as the opening and closing speeds, are characterized by a very great dispersion, so that It is not always possible to obtain correct operation at high weaving rates.

La présente invention vise une pince pour fil qui ne présente pas les désavantages évoqués. A cette fin, l'invention prévoit une pince ayant pour caractéristique de comporter un mécanisme d'entraînement composé essentiellement d'au moins un élément piézo-électrique à action inverse. Un tel élément piézo-électrique à action inverse se compose d'un ou plusieurs cristaux piézo-électriques pourvus des connexions électriques requises, l'application d'une tension électrique appropriée permettant classiquement d'obtenir une déformation du cristal piézo-électrique, en expansion ou en contraction. Cette déformation est exploitée pour fermer ou ouvrir la pince.The present invention relates to a wire clamp which does not have the disadvantages mentioned. To this end, the invention provides a clamp having the characteristic of comprising a drive mechanism consisting essentially of at least one piezoelectric element with reverse action. Such a reverse action piezoelectric element consists of one or more piezoelectric crystals provided with the required electrical connections, the application of an appropriate electrical voltage conventionally making it possible to obtain a deformation of the expanding piezoelectric crystal. or in contraction. This deformation is used to close or open the clamp.

Les avantages de la pince pour fil piézo-électrique selon l'invention consistent dans la faible quantité d'énergie électrique requise pour son fonctionnement, dans son temps de réaction extrêmement rapide, dans le fait que sa force de serrage est totalement contrôlable, dans le caractère relativement peu onéreux de sa réalisation et, enfin, dans son faible encombrement au montage dans une machine à tisser.The advantages of the pliers for piezoelectric wire according to the invention consist in the small amount of electrical energy required for its operation, in its extremely rapid reaction time, in the fact that its clamping force is completely controllable, in the relatively inexpensive nature of its production and, finally, in its small size when mounted in a weaving machine.

Il est clair que l'utilisation de telles pinces sur une machine à tisser permet d'utiliser une commande entièrement électronique pour les réglages nécessaires après un arrêt machine, éliminant les réglages mécaniques fastidieux tels qu'une marche arrière soigneusement dosée d'un système de cames, par exemple.It is clear that the use of such pliers on a weaving machine makes it possible to use a fully electronic control for the adjustments necessary after a machine stop, eliminating the tedious mechanical adjustments such as a carefully measured reverse of a system of cams, for example.

Il est clair aussi qu'une pince pour fil selon l'invention, outre son emploi comme pince pour fil de trame, pourra être utilisée à d'autres points d'une machine à tisser et en particulier à tous les points requérant des pinces dont le fonctionnement exige une commande très précise.It is also clear that a thread clamp according to the invention, in addition to its use as a weft clamp, can be used at other points of a weaving machine and in particular at all points requiring clamps, operation requires very precise control.

Afin de mieux mettre en lumière les caractéristiques de l'invention, on trouvera ci-après la description, donnée à titre d'exemple seulement et sans aucun caractère limitatif, de quelques formes d'exécution préférentielles, avec références aux dessins annexés, dans lesquels:

  • la figure 1 représente une pince pour fil selon l'invention;
  • la figure 2 représente la pince illustrée à la figure 1 en position fermée;
  • la figure 3 représente une variante selon l'invention;
  • la figure 4 représente la pince illustrée à la figure 3 en position fermée;
  • les figures 5 et 6 représentent des graphiques illustrant le rapport entre la tension appliquée et la force de serrage obtenue;
  • les figures 7 à 9 représentent une autre variante selon l'invention, ainsi que son utilisation;
  • la figure 10 représente une application de pinces selon l'invention.
In order to better highlight the characteristics of the invention, the description below, given by way of example only and without any limiting nature, of a few preferred embodiments, with reference to the accompanying drawings, in which :
  • Figure 1 shows a wire clamp according to the invention;
  • Figure 2 shows the clamp illustrated in Figure 1 in the closed position;
  • FIG. 3 represents a variant according to the invention;
  • FIG. 4 represents the clamp illustrated in FIG. 3 in the closed position;
  • Figures 5 and 6 show graphs illustrating the relationship between the applied voltage and the clamping force obtained;
  • Figures 7 to 9 show another variant according to the invention, as well as its use;
  • FIG. 10 represents an application of pliers according to the invention.

Dans la forme d'exécution illustrée aux figures 1 et 2, l'élément piézo-électrique à action inverse est formé par un cristal piézo-électrique 1 fixé à demeure sur un support 3 à l'une de ses extrémités 2, et dont l'autre extrémité 4, libre, forme un élément de serrage ou face de serrage pouvant interagir avec un autre élément ou face de serrage 5, fixé à demeure sur le support 3. Afin d'éviter l'usure du cristal piézo-électrique, la face de serrage 4 peut être munie d'une mordache 6 résistante à l'usure réalisée par exemple dans une matière céramique. Bien entendu, la face de serrage 5 peut elle aussi être pourvue d'un revêtement céramique ou autre.In the embodiment illustrated in Figures 1 and 2, the piezoelectric element with reverse action is formed by a piezoelectric crystal 1 fixed permanently on a support 3 at one of its ends 2, and whose l other end 4, free, forms a clamping element or clamping face which can interact with another element or clamping face 5, fixed permanently to the support 3. In order to avoid wear of the piezoelectric crystal, the clamping face 4 can be provided with a wear-resistant jaw 6 made for example from a ceramic material. Of course, the clamping face 5 can also be provided with a ceramic or other coating.

Eventuellement, l'ensemble de ce dispositif peut comporter des couches de matériau élastique 7 destinées à amortir les chocs ou les vibrations et interposées par exemple, comme illustré aux figures 1 et 2, entre le cristal 1 et la mordache 6 résistante à l'usure et/ou entre la face de serrage 5 et la partie du support 3 sur laquelle elle s'appuie.Optionally, the assembly of this device may include layers of elastic material 7 intended to absorb shocks or vibrations and interposed for example, as illustrated in FIGS. 1 and 2, between the crystal 1 and the wear-resistant jaw 6 and / or between the clamping face 5 and the part of the support 3 on which it rests.

Par ailleurs, le cristal piézo-électrique 1 est pourvu des connexions électriques 8 auxquelles on peut appliquer une tension électrique appropriée V, par exemple à l'aide d'une alimentation électrique 9 comme illustré de manière schématique à la figure 1.Furthermore, the piezoelectric crystal 1 is provided with electrical connections 8 to which an appropriate electrical voltage V can be applied, for example using an electrical supply 9 as illustrated diagrammatically in FIG. 1.

Le fonctionnement de la pince pour fil est illustré aux figures 1 et 2. Dans le schéma de la figure 1, la tension appliquée V possède une valeur V1 donnée et la pince n'exerce aucune force de serrage ou de freinage, de sorte que le fil 10 passe librement entre les faces de serrage. Dans le schéma de la figure 2, la tension appliquée possède une valeur V2 inférieure à V1, entraînant une expansion du cristal proportionnelle à la baisse de tension, de sorte que le fil 10 est calé entre la mordache 6 et la face de serrage 5. Cela étant, la force de serrage augmentera proportionnellement à toute baisse plus importante de la tension V.The operation of the wire clamp is illustrated in FIGS. 1 and 2. In the diagram in FIG. 1, the applied voltage V has a given value V1 and the clamp does not exert any clamping or braking force, so that the wire 10 passes freely between the clamping faces. In the diagram of FIG. 2, the applied voltage has a value V2 lower than V1, causing an expansion of the crystal proportional to the drop in voltage, so that the wire 10 is wedged between the jaw 6 and the clamping face 5. However, the clamping force will increase in proportion to any greater drop in voltage V.

Les figures 3 et 4 représentent une autre variante d'exécution, faisant appel à un cristal piézo-électrique incurvable 11 dont l'importance de la courbure est fonction de la grandeur de la tension V appliquée. Le cristal piézo-électrique 11 est fixé à demeure à l'une de ses extrémités 12 et pourvu, à l'autre extrémité 13, d'une face de serrage 4 formée par une mordache 6 similaire à celle de la variante d'exécution illustrée aux figures 1 et 2. Cette mordache peut interagir avec un élément de serrage ou face de serrage fixe 5.Figures 3 and 4 show another alternative embodiment, using a curved piezoelectric crystal 11 whose magnitude of the curvature is a function of the magnitude of the voltage V applied. The piezoelectric crystal 11 is fixed permanently to one of its ends 12 and provided, at the other end 13, with a clamping face 4 formed by a jaw 6 similar to that of the variant embodiment illustrated in FIGS. 1 and 2. This jaw can interact with a clamping element or fixed clamping face 5.

L'extrémité 12, fixée à demeure, est pourvue des connexions électriques 8 requises.The end 12, fixed permanently, is provided with the required electrical connections 8.

Le fonctionnement de la pince selon la forme d'exécution illustrée aux figures 3 et 4 se déduit sans difficulté des schémas des illustrations. Dans l'état où une tension V=V3 est appliquée, le cristal piézo-électrique 11 affecte la forme illustrée à la figure 3. Lorsqu'on applique une tension inférieure V=V4, la forme du cristal piézo-électrique 11 se modifiera comme illustré à la figure 4, de telle sorte que les faces de serrage 4 et 5 interagissent. La force de serrage sera déterminée, comme précédemment, par la tension V appliquée.The operation of the clamp according to the embodiment illustrated in Figures 3 and 4 can easily be deduced from the diagrams of the illustrations. In the state where a voltage V = V3 is applied, the piezoelectric crystal 11 takes the shape illustrated in FIG. 3. When a lower voltage V = V4 is applied, the shape of the piezoelectric crystal 11 will change as illustrated in Figure 4, so that the clamping faces 4 and 5 interact. The clamping force will be determined, as before, by the voltage V applied.

Les figures 5 et 6 illustrent, pour un exemple d'exécution, la relation entre le régime de la tension V appliquée aux connexions électriques 8 et la force de serrage F correspondante. Dans la première phase A, la tension V a une valeur élevée telle que la pince est complètement ouverte, la force de serrage étant F=0 dans ce cas. Au cours de la phase B, la tension V est réduite de telle sorte que la pince commence à exercer une certaine force de serrage F1 sur le fil placé dans la pince. Une force de serrage supérieure F2 peut être atteinte en réduisant encore la tension appliquée, comme illustré dans la phase C.Figures 5 and 6 illustrate, for an exemplary embodiment, the relationship between the speed of the voltage V applied to the electrical connections 8 and the corresponding clamping force F. In the first phase A, the voltage V has a high value such that the clamp is completely open, the clamping force being F = 0 in this case. During phase B, the voltage V is reduced so that the clamp begins to exert a certain clamping force F1 on the wire placed in the clamp. A higher clamping force F2 can be achieved by further reducing the applied voltage, as illustrated in phase C.

Les figures 7 à 9 illustrent une autre forme d'exécution qui fait appel à deux cristaux piézo-électriques 14 et 15 disposés de manière à se faire face. Leurs extrémités distantes 16 et 17 sont fixées à demeure, tandis que leurs extrémités proches 18 et 19, pourvues de mordaches résistantes à l'usure, sont placées en vis-à-vis.Figures 7 to 9 illustrate another embodiment which uses two piezoelectric crystals 14 and 15 arranged so as to face each other. Their distant ends 16 and 17 are fixed permanently, while their close ends 18 and 19, provided with wear-resistant jaws, are placed opposite.

Le fonctionnement de cette pince se déduit aisément des schémas représentés aux figures 7 à 9. L'expansion du cristal piézo-électrique 14 seulement, comme illustré à la figure 8, permet d'obtenir une force de serrage peu importante, tandis que l'expansion des deux cristaux piézo-électriques 14 et 15 à la fois, comme illustré à la figure 9, génère une force de serrage importante.The operation of this clamp is easily deduced from the diagrams represented in FIGS. 7 to 9. The expansion of the piezoelectric crystal 14 only, as illustrated in FIG. 8, makes it possible to obtain a small clamping force, while the expansion of the two piezoelectric crystals 14 and 15 at the same time, as illustrated in FIG. 9, generates a large clamping force.

Cette dernière variante d'exécution offre l'avantage de fournir, d'une part, une force de serrage réglable _ à deux valeurs il est vrai _ lorsqu'une seule tension est appliquée, et d'autre part, un passage relativement important pour le fil 10 lorsque les deux cristaux 14 et 15 sont mis sous tension à la fois.This last variant offers the advantage of providing, on the one hand, an adjustable clamping force _ two values it is true _ when only one tension is applied, and on the other hand, a relatively large passage for the wire 10 when the two crystals 14 and 15 are energized at the same time.

Il est clair qu'une telle pince à double action pourra également être réalisée en faisant appel à deux cristaux piézo-électriques incurvables 11 du type évoqué précédemment. Dans une telle variante d'exécution, les éléments piézo-électriques 11 ou 14-15 ne doivent pas nécessairement être montés en vis-à-vis. Ils pourront, par exemple, être placés l'un sur l'autre selon un montage en série, pour ainsi dire, auquel cas ils entreront en interaction avec une face de serrage fixée à demeure. Un tel montage en série pourra également être constitué de plusieurs cristaux piézo-électriques, l'application d'une seule valeur de tension V permettant alors d'obtenir une force de serrage réglable à plusieurs pas. Il va de soi que ces variantes d'exécution pourront également comporter une couche de matériau amortissant 7.It is clear that such a double action clamp may also be produced by using two curved piezoelectric crystals 11 of the type mentioned above. In such an alternative embodiment, the piezoelectric elements 11 or 14-15 do not necessarily have to be mounted opposite. They can, for example, be placed one on the other in a series arrangement, so to speak, in which case they will interact with a clamping face permanently fixed. Such a series connection could also consist of several piezoelectric crystals, the application of a single voltage value V then making it possible to obtain a clamping force adjustable in several steps. It goes without saying that these variant embodiments may also include a layer of damping material 7.

La figure 10 représente un montage d'un mécanisme de conduite du fil de trame pour machines à tisser, faisant appel à quatre pinces pour fil 20 à 23. Par ailleurs, ce mécanisme de conduite de trame prévoit essentiellement un porte-bobine 24, un dispositif de fourniture 25 formé par des rouleaux dévideurs 26 et un tube cylindrique 27 dans lequel le fil de trame 10 est stocké sous forme spiralée, un souffleur principal 28 et un peigne 29 en U de préférence.FIG. 10 shows an assembly of a weft thread driving mechanism for weaving machines, using four thread clamps 20 to 23. Furthermore, this weft driving mechanism essentially provides a reel holder 24, a supply device 25 formed by reel rollers 26 and a cylindrical tube 27 in which the weft thread 10 is stored in spiral form, preferably a main blower 28 and a comb 29 in a U shape.

La première pince 20, placé à la sortie du tube cylindrique 25, a pour fonction de bloquer aux moments requis le fil pris dans le tube. Il est à noter qu'une telle pince piézo-électrique 20 s'avère particulièrement avantageuse sur les dispositifs de fourniture de fil de trame du type dans lequel le fil de trame 10, comme illustré à la figure 20, est stocké sous forme spiralée dans un tube cylindrique 27 et plus généralement sur tout dispositif de fourniture dans lequel la longueur de la duite n'est pas déterminée directement par la forme du fournisseur. Sur de tels dispositifs en effet, la détermination exacte de la duite à insérer nécessite un réglage précis de la pince 20 agissant comme pince d'insertion de trame. Cette précision concerne tant les temps d'ouverture et de fermeture que les vitesses d'ouverture et de fermeture et le dosage de la force de serrage. Il est clair qu'une pince pour fil piézo-électrique selon l'invention permet de répondre à ces exigences de manière bien plus rigoureuse que les pinces classiques.The first clamp 20, placed at the outlet of the cylindrical tube 25, has the function of blocking at the required moments the wire taken in the tube. It should be noted that such a piezoelectric clamp 20 proves to be particularly advantageous on weft yarn supply devices of the type in which the weft yarn 10, as illustrated in FIG. 20, is stored in spiral form in a cylindrical tube 27 and more generally on any supply device in which the length of the pick is not directly determined by the shape of the supplier. On such devices in Indeed, the exact determination of the pick to be inserted requires precise adjustment of the clamp 20 acting as a weft insertion clamp. This precision concerns both the opening and closing times, the opening and closing speeds and the dosage of the clamping force. It is clear that a clamp for piezoelectric wire according to the invention makes it possible to meet these requirements in a much more rigorous manner than conventional clamps.

Le fonctionnement de la pince 20 détermine largement le fonctionnement de l'ensemble du mécanisme d'insertion de trame. Lorsque la pince 20 est fermée, une certaine quantité de fil est soufflée dans le tube cylindrique 25 où elle s'accumule en se déposant en spirale le long de la paroi intérieure du tube. A l'ouverture de la pince 20, le fil de trame est libéré; à la fin de l'insertion, la fermeture complète de la pince 20, avec application d'une force de serrage élevée, entraîne le blocage du fil de trame 10 au moment où son extrémité libre atteint la fin de la foule. Comme la pince 20 est amenée à se fermer brusquement, elle sera de préférence pourvue d'une couche de matériau amortissant 7.The operation of the clamp 20 largely determines the operation of the entire weft insertion mechanism. When the clamp 20 is closed, a certain amount of wire is blown into the cylindrical tube 25 where it accumulates by depositing in a spiral along the inner wall of the tube. At the opening of the clamp 20, the weft thread is released; at the end of the insertion, the complete closure of the clamp 20, with the application of a high clamping force, causes the weft thread 10 to be blocked when its free end reaches the end of the crowd. As the clamp 20 is caused to abruptly close, it will preferably be provided with a layer of damping material 7.

La deuxième pince 21 est placée à l'extrémité de la foule. On sait qu'au freinage d'un fil de trame par la pince 20 lorsque ce fil atteint la fin de la foule, sa force d'inertie lui impose un allongement élastique suivi d'une contraction, se traduisant par un effet de recul de l'extrémité du fil 10. Pour éviter ce recul et, par conséquent, empêcher la formation de boucles dans le tissu, on redresse classiquement le fil 10 à l'aide d'un guide-trame pneumatique qui intercepte l'extrémité avant du fil de trame. L'interception et le redressement du fil pourraient cependant être réalisés également par une pince offrant un temps de réaction suffisamment réduit pour saisir le fil dans un délai adéquat au reçu d'un signal de commande. Si la pince se ferme trop rapidement, le fil se nouera; si elle se ferme trop lentement, le fil formera une boucle dans la foule lors de son retrait, comme mentionné ci-dessus. En raison de son temps de réaction réduit, une pince piézo-électrique 21 selon l'invention se prête particulièrement à l'application que l'on vient de décrire. Etant donné que la pince 21 doit être capable, en position ouverte, d'intercepter le fil de trame inséré dans la foule, elle devra présenter de préférence un passage relativement large en position ouverte. Il est dès lors indiqué de recourir pour cette application à une pince pour fil du type illustré à la figure 7 ou encore, une pince intégrant un ou plusieurs cristaux piézo-électriques montés en série. La présence du fil 10 sera de préférence détectée par les cristaux piézo-électriques de la pince 21 elle-même, de manière à générer le signal de commande évoqué précédemment.The second clamp 21 is placed at the end of the crowd. It is known that when a weft thread is braked by the clamp 20 when this thread reaches the end of the crowd, its force of inertia imposes an elastic elongation followed by a contraction, resulting in a recoil effect of the end of the wire 10. To avoid this recoil and, consequently, to prevent the formation of loops in the fabric, the wire 10 is conventionally straightened using a pneumatic weft guide which intercepts the front end of the wire weft. Interception and straightening of the wire could however also be carried out by pliers offering a sufficiently short reaction time to grasp the wire within an adequate time on receipt of a command signal. If the clip closes too quickly, the thread will tie; if it closes too slowly, the wire will form a loop in the crowd when it is removed, as mentioned above. Due to its reduced reaction time, a piezoelectric clamp 21 according to the invention is particularly suitable for the application which has just been described. Since the clamp 21 must be capable, in the open position, of intercepting the weft thread inserted in the crowd, it should preferably have a relatively wide passage in the open position. It is therefore advisable to use for this application a wire clamp of the type illustrated in Figure 7 or, a clamp incorporating one or more piezoelectric crystals connected in series. The presence of the wire 10 will preferably be detected by the piezoelectric crystals of the clamp 21 itself, so as to generate the control signal mentioned above.

De manière analogue, on peut recourir à une pince piézo-électrique pour retenir le fil de trame du côté insertion. Ici encore, une force de serrage élevée et un passage relativement large pour le fil 10 sont deux facteurs très importants.Similarly, a piezoelectric clamp can be used to hold the weft thread on the insertion side. Here again, a high clamping force and a relatively large passage for the wire 10 are two very important factors.

La troisième pince 22 assure le redressement du fil 10 devant les rouleaux dévideurs 26. Dans la variante d'exécution illustrée, la pince 22 est formée par deux cristaux incurvables 11 pouvant travailler en interaction et capables de serrer le fil 10 entre les mordaches 6.The third clamp 22 straightens the wire 10 in front of the unwinding rollers 26. In the illustrated embodiment, the clamp 22 is formed by two curved crystals 11 which can work in interaction and capable of clamping the wire 10 between the jaws 6.

La quatrième pince 23, montée juste devant le souffleur principal 28, peut exercer une force de pression réglable sur un fil, de sorte que le fil 10 peut être freiné progressivement lorsqu'il atteint la fin de la foule, de manière à éviter les surtensions et réduire le risque de rupture du fil de trame.The fourth clamp 23, mounted just in front of the main blower 28, can exert an adjustable pressing force on a wire, so that the wire 10 can be braked gradually when it reaches the end of the crowd, so as to avoid overvoltages and reduce the risk of breakage of the weft thread.

Il est à noter que le montage donné à la figure 10 illustre toute une série de possibilités d'applications de la pince pour fil piézo-électrique selon l'invention. Ainsi, la première pince 20 a pour fonction de bloquer un fil en mouvement. La deuxième pince 21 sert uniquement à saisir un fil. Les troisième et quatrième pinces, 22 et 23 respectivement, ont une fonction de freinage et n'exercent qu'une force de serrage réduite sur le fil en mouvement 10.It should be noted that the assembly given in FIG. 10 illustrates a whole series of possible applications of the clamp for piezoelectric wire according to the invention. Thus, the first clamp 20 has the function of blocking a moving wire. The second clamp 21 is used only to grip a wire. The third and fourth clamps, 22 and 23 respectively, have a braking function and exert only a reduced clamping force on the moving wire 10.

Il est évident que la commande des différentes pinces pourra être réalisée dans un grand nombre de variantes et que la présente invention ne se limite aucunement aux versions d'exécution données à titre d'exemple et illustrées aux figures; au contraire, les pinces pour fil selon l'invention pourront être réalisées selon différentes formes et dimensions sans quitter le cadre de l'invention.It is obvious that the control of the different clamps can be carried out in a large number of variants and that the present invention is in no way limited to the execution versions given by way of example and illustrated in the figures; on the contrary, the wire clamps according to the invention can be produced in different shapes and dimensions without leaving the scope of the invention.

Claims (10)

1. Thread clip characterized in that its movement is primarily guaranteed by at least one piezoelectric element acting inversely (1; 11; 14; 15).
2. Thread clip according to claim 1, characterized in that it is essentially composed of at least one piezoelectric crystal (1), one of the ends of which is fixed, and the other end of which is free, forming a first clamping surface (4) which can work upon a second fixed clamping surface (5) as a result of the deformation of the crystal (1).
3. Thread clip according to claim 1, characterized in that it is essentially composed of two piezoelectric crystals (14, 15) arranged such that they face each other, and whose far ends (16, 17) are fixed, whereas the nearby ends (18, 19) are mounted opposite each other and can work upon each other as a result of the deformation of the crystals (14, 15).
4. Thread clip according to claim 1, characterized in that the piezoelectric element is composed of a curvable crystal (11), one of the ends of which (12) is fixed, whereas the other end (13) is provided with a laterally positioned clamping surface (4).
5. Thread clip according to claim 1, characterized in that it is essentially composed of two curvable piezoelectric crystals (11) whose free ends can work upon each other.
6. Thread clip according to any of the above claims, characterized in that either one or both the piezoelectric crystals are connected to an adjustable power supply (9).
7. Thread clip according to claims 3 or 5, characterized in that the two piezoelectric crystals (11; 14-15) are controlled by one and the same electric current (V), the relative position of the two crystals being such that the expansion of either one of them exerts a reduced clamping pressure on a yarn (10), whereas the expansion of both crystals exerts an increased clamping pressure on the yarn (10).
8. Thread clip according to any of the above claims, characterized in that at least the clamping surface (4) formed by the end of the element or the piezoelectric crystal is provided with a hard-wearing clip piece (6).
9. Thread clip according to claim 8, characterized in that a layer of elastic damping material (7) is placed between the element or the piezoelectric crystal and the hard-wearing clip piece (6).
10. Thread clip according to any of the above claims, characterized in that a layer of elastic damping material (7) is placed between the clamping surface (5) and the support (3) upon which it rests.
EP19880201286 1987-06-29 1988-06-22 Thread clip Expired - Lifetime EP0299553B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE8700726 1987-06-29
BE8700726A BE1000703A4 (en) 1987-06-29 1987-06-29 Wire clamp.

Publications (2)

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EP0299553A1 EP0299553A1 (en) 1989-01-18
EP0299553B1 true EP0299553B1 (en) 1991-03-06

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DE (1) DE3861932D1 (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2648120B1 (en) * 1989-06-09 1991-12-13 Steib Bertrand BRAKING DEVICE WITH PRESET ADJUSTMENT AND AUTOMATIC CONTROL FOR A MOVING WIRE
JPH07331558A (en) * 1994-06-06 1995-12-19 Toyota Autom Loom Works Ltd Weft-insertion method for rapier loom and apparatus therefor
FR2741332B1 (en) * 1995-11-17 1998-01-02 Giat Ind Sa DEVICE FOR LOCKING A DRIVING LINE DRIVEN IN TRANSLATION
DE29808997U1 (en) 1998-05-18 1998-07-30 Textilma Ag, Hergiswil Gripper and a weft insertion device for a rapier weaving machine
DE19852794B4 (en) * 1998-11-16 2004-03-25 Lindauer Dornier Gmbh Controllable weft feeder and clamping device for weaving machines
IT1304701B1 (en) * 1998-12-11 2001-03-28 Vamatex Nuova Spa PIEZOELECTRIC ACTUATOR IN PARTICULAR FOR THE APPLICATION IN TEXTILE MACHINES
EP1552048B1 (en) * 2002-09-18 2007-03-14 Lindauer Dornier Gesellschaft M.B.H Method for holding a weft yarn, jet weaving machine comprising a clamping device for the weft yarn, particularly serving to carry out this method, and cartridge provided in the form of an exchangeable modular unit for placing inside the mixing tube of a jet weaving machine
CN107671431B (en) * 2016-08-02 2023-08-04 北京清大天达光电科技股份有限公司 Wire clamping device with pneumatic clamping hand
CN112779650B (en) * 2020-12-29 2022-09-20 西安工程大学 Piezoelectric driving flexible hinged yarn stop pin

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Publication number Priority date Publication date Assignee Title
GB1076929A (en) * 1963-09-19 1967-07-26 Ramon Balaguer Golobart Device for clamping and releasing weft yarns
DE2364680C2 (en) * 1973-12-27 1982-08-26 Rüti-te Strake B.V., 5750 Deurne Solenoid operated thread clamp or cutting device or the like for weaving machines

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BE1000703A4 (en) 1989-03-14
EP0299553A1 (en) 1989-01-18
DE3861932D1 (en) 1991-04-11

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