EP1063326A1 - Method and device for positioning warp threads in a loom and loom with such a device - Google Patents

Abstract

At a loom harness, where the warps are moved to form the shed for weft insertion, a common monitor (20,21) registers the presence of all the warps (1) moved by different electrical actuators (6), to establish the passage of at least one warp in a set position. A further monitor (10) registers the value (θ 0) of a parameter (θ ) of the actuator (6) command, according to the passage of the warp (1) in the given position. A warp (1) to be registered (S2) is shifted into the set position, and the parameter (θ ) for the actuator (6) command is selected during the warp movement in that position, and the selected parameter value (θ 0) is used as a reference value for the actuator (6) command. The first monitor (20,21) is mounted to the loom frame, with a transmitter (20) to generate a wave signal to be registered by a facing receiver cell (21) on the other side of the warps (1), which can detect a signal change. The transmitter (20) can be a helium-neon gas laser or a laser diode, which sends a laser beam (22), and the receiver (21) determines any change in the laser beam intensity while the warps (1) are in the beam path. The receiver can have a thread structure, aligned on a global direction (F2) parallel to the wefts. The first monitor can have a trolley moving along a support parallel to the warps, fitted with a receiver by a contact to act selectively with one of the warps. The trolley is integrated with an extension, to make contact with certain warps. The contacts between the warps and the extension generate a force to shift the trolley on its support. An Independent claim is included for a warp displacement action where at least one warp (1) is shifted by an actuator (6). The passage of at least one warp is registered (S2) at a given position. A value is selected of a command parameter (θ ) for the actuator during the passage of the warp in the set position, and the selected value (θ 0) is used as a reference value for the command of the actuator. Preferred Features: The selected parameter value (θ 0) is used for that parameter to determine at least one control value of the parameter matching at least one particular point in the warp (1) movement through the action of the actuator (6). A number of warps can be shifted by a single actuator, where their passage is detected at a given point, and a selected parameter value (θ 0) is used to control the actuator for at least one warp.

Description

The invention relates to a method and a device for positioning of warp threads and an equipped loom of such a device.

• Lors de la fabrication du harnais, les arcades sont ajustées manuellement et individuellement à la longueur requise.
• Lors de la mise en place de la mécanique Jacquard sur sa structure porteuse, le positionnement de cette mécanique est ajusté en agissant manuellement sur des vérins, afin de corriger la hauteur des oeillets des lisses.

In the field of weaving looms of the Jacquard type, it is known to carry out the equalization of the harness, that is to say the adjustment, relative to the frame of the loom, of the position of the eyelets of the heddles in their direction of movement according to their substantially vertical reciprocating movement, the aim being to obtain high precision in the positioning of the warp threads during weaving. In known devices, this adjustment generally takes place in two stages:

• When manufacturing the harness, the arches are manually and individually adjusted to the required length.
• When setting up the Jacquard mechanism on its support structure, the positioning of this mechanism is adjusted by acting manually on jacks, in order to correct the height of the heald eyelets.

These manual adjustments are long, tedious, expensive and always imprecise, and their quality can be influenced by operator fatigue or deconcentration.

It is to these disadvantages that we hear more particularly remedy the invention by proposing a positioning device warp threads which can be used automatically, with greatly improved accuracy and reproducibility compared to known techniques.

In this spirit, the invention relates to a device for positioning of warp-woven warp threads for crowd formation by electric actuators, which includes a first means, common to trained sons by different actuators, detecting the passage of at least a chain wire in a determined position and a second means for determining the value of a control parameter of the corresponding actuator when passing a wire through this position.

Thanks to the invention, it is possible to move a wire of chain or a group of chain wires by activating an actuator to a predetermined position, which can be verified by the first means, while the second means allows to acquire a value of a command parameter of the actuator which can then be used as a value of reference for the control of this actuator.

According to a first advantageous variant of the invention, the first means is a fixed detection assembly on a building of the trade and comprising a source of emission of a wave signal and a cell arranged opposite this source with respect to the chain wires and capable of detecting a variation of the wave signal. In particular, this source can be a laser beam emitter, while the cell is able to detect a variation in intensity of this beam which occurs when one of the chain wires interferes with the laser beam.

According to a second alternative embodiment of the invention, the first means comprises a filiform sensor arranged according to a direction parallel to the weft threads of the loom.

According to a third alternative embodiment, the first medium comprises a carriage movable along a support extending in a direction generally parallel to the wires of frame of the trade, this trolley being equipped with a sensor by contact capable of cooperating selectively with one of the sons of chain. In this case, provision can be made for the carriage to be secured to an extension capable of coming into contact with certain sons of chain of the trade, the contacts between these sons chain and this extension to generate an effort of movement of the carriage on the support.

Whatever the variant envisaged for the first medium, it can be implemented automatically, i.e. reproducibly and reliably.

The invention also relates to a loom comprising a device as previously described. Such a profession works safer and more precisely than trades known while its installation and maintenance are greatly simplified.

• déplacer au moins un fil de chaíne au moyen de l'actionneur qui lui est associé ;
• détecter le passage de ce fil de chaíne dans une position prédéterminée ;
• sélectionner la valeur d'un paramètre de commande de cet actionneur lors du passage du fil dans cette position et
• utiliser la valeur sélectionnée comme valeur de référence pour la commande de l'actionneur.

The invention also relates to a method of positioning the warp threads of a weaving loom which can be implemented with the device described above and, more specifically, a method which consists in:

• move at least one chain wire by means of the actuator associated therewith;
• detecting the passage of this chain wire in a predetermined position;
• select the value of a control parameter of this actuator when the wire passes into this position and
• use the selected value as a reference value for actuator control.

This process has the advantage of being automated and allow adjustment of the heald stroke from one loom to weave by programming the associated electric actuator to each boom or group of rails without manual intervention on the arches. In other words, any faults alignment between the beams and arches can be compensated by controlling the electric actuator from the value selected as a reference value which corresponds to a same position for the different warp threads.

According to an advantageous aspect of the invention, the method consists in using the selected value of the parameter for the determination of at least one setpoint value of the parameter corresponding to at least one particular position of the movement wire generated by the actuator. Thanks to this aspect of the invention, the selected value allows positioning with precision chain son throughout their trajectory.

According to another advantageous aspect, the method is applicable when several chain threads are moved thanks to a single actuator, which is the case in a loom equipped with a dobby or in a loom type Jacquard with several patterns repeated across the width of the fabric. In this case, the passage of at least one of the son of chain driven by the actuator in the determined position and we use the selected value of the parameter for the command of the actuator. For example, we can detect, in a group of several wires, the first wire reaching the position predetermined and the last wire reaching this position, two actuator control parameter values selected and used by a control unit to control actuator, the first value can be used for the determination of the bottom dead center of the corresponding stroke, the second value being used for point determination dead high.

• la figure 1 est une représentation schématique de principe d'un métier à tisser conforme à l'invention ;
• la figure 2 est un représentation analogue à la figure 1 pour un dispositif conforme à un second mode de réalisation de l'invention et
• la figure 3 est une représentation de principe, en vue de face, d'un dispositif conforme à un troisième mode de réalisation de l'invention.

The invention will be better understood and other advantages of it will appear more clearly in the light of the following description of three embodiments of a device in accordance with its principle and of their methods of implementation, given by way of example only and with reference to the appended drawings in which:

• Figure 1 is a schematic representation of the principle of a weaving loom according to the invention;
• FIG. 2 is a representation similar to FIG. 1 for a device according to a second embodiment of the invention and
• Figure 3 is a principle representation, in front view, of a device according to a third embodiment of the invention.

The weaving loom shown diagrammatically in FIG. 1 comprises warp threads 1 each passing through an eyelet 2 of a heddle 3 driven by a vertical oscillation movement represented by the arrow F ₁ generally perpendicular to the direction of movement of the threads weft represented by arrow F ₂ . Each stringer 3 is connected by a cord 4 to a pulley 5 driven in rotation by an electric servomotor 6. In its lower part, each stringer 3 is connected by a rod 7 to a spring 8 secured to the frame 9 of the loom.

As shown for the rightmost motor 6 in FIG. 1, each motor is controlled by a control unit 10 which delivers to the motor 6 a control instruction corresponding to given angular positions of the motor. Each position may be defined by a  parameter representative of the instantaneous angular position of rotation of the shaft 6a of the motor 6, the motor control being performed using the  parameter as a desired value.

A detector 11 installed at the rear of each motor 6 is provided to cooperate with a cup 12 rotated by the shaft 6 a . The encoder formed of the elements 11 and 12 makes it possible to produce a position control, for precise control of the motor 6, by means of a signal S _{1 which} it addresses to the unit 10 by an electrical connection 13.

A laser 20 is placed opposite a target 21, so that the light beam 22 which it emits is generally parallel to the direction F ₂ of the weft yarns 24. The target 21 constitutes a sensor capable of detecting a variation intensity of the beam 22 when this beam interferes with one of the chain wires 1. Under these conditions, the cell 21 sends to the unit 10, through an electrical connection 14, a signal S ₂ signifying that the wire of chain 1 in question is in the position of interference with the beam 22.

The positioning process consists first of all in removing all the chain wires from the bundle 22, by bringing them above or below the latter. Then, each wire 1 is successively moved in the direction of the beam 22 until the assembly formed of the elements 20 and 21 detects that the corresponding chain wire 1 is in the intersection position of the beam 22. During the interference between a wire 1 and the harness 22, the unit 10 stores the set value  ₀ of the parameter  which corresponds to this position for the corresponding actuator 6.

It is assumed that the laser 20 and the target 21 are arranged so that the beam 22 is slightly above the plane of intersection of the chain strands, that is to say the median plane of the crowd. P ₀ denotes the position of the eyelet 2 of a heddle 3 when the wire passing through this eyelet reaches the bundle 22. The position P ₀ corresponds to the value  ₀ of the parameter  for controlling the motor 6. This value  ₀ can therefore be considered as corresponding to a reference position of the movement of the wire 1.

From this position P ₀ , all the other positions of the boom can be determined by the unit 10, by calculation. In particular, the top dead center and the bottom dead center of the beam path can be calculated.

According to alternative embodiments of the invention, the means for detecting the position of the warp threads may comprise a linear capacitive sensor disposed in the direction F ₂ of the weft threads 24 of the loom.

Any light source can be used for this invention, provided that a suitable cell is used. of the satisfactory results have been obtained with a gas laser from the helium-neon type and with a diode laser, which are commercial products whose cost is well controlled.

In the second embodiment of the invention shown in FIG. 2, elements similar to those of the first embodiment bear identical references increased by 50. In this second embodiment, only a beam 53 for controlling the vertical displacement F ₁ of a chain wire 51 through an eyelet 52, has been shown. This heddle is associated with a cord 54 intended to be wound on a pulley 55, this pulley being controlled in rotation R by a servomotor 56. In the lower part, a rod 57 connects the heald 53 to a spring 58 secured to the frame 59 of the job. A motor control unit 60 makes it possible to control, this motor in position as a function of set values  corresponding to each of its positions of its shaft 56 a .

A wire 70 is stretched, parallel to the direction F ₂ of the weft son 74, between two parts of the frame of the loom and it constitutes a sensor for the arrival of a chain wire 51 at its height because the contact between the wires 51 and 70 generate vibrations which can be detected by a piezoelectric cell 71 connected by an electric line 64 to the unit 60.

According to a variant not shown of the invention, the wire 70 may not be stretched between the two parts of the frame, in which case its exact geometry is taken into account for compensate for differences in height of detected positions.

Whether the wire is tight or not, we can plan to generate vertical vibrations on wire 51 thanks to the actuator 56, these vibrations being easily detected by the cell 71.

When a chain wire impacts the wire 70, this is detected by the cell 71 which transmits, by an electric line 64, a signal S ₂ to the unit 60. The unit 60 then selects the instantaneous set value  ₀ of the control parameter  as a reference value for determining the path of the arm 53. As previously, this value can be used as the basis for the determination, by calculation, of all the positions of the arm 53 and of the associated wire 51 .

In the third embodiment of the invention shown in Figure 3, elements similar to those of the first embodiment bear identical references increased by 100. The son of warp 101 of a loom are provided to be moved by heddles 103 which they pass through the eyelets 102. A beam 175 is disposed above the warp threads, parallel to the direction F ₂ of the weft threads and in front of the loom harness, this beam being in abutment on the frame 176 of the trade. A carriage 177 is movable in translation along the beam 175 and is fitted with rollers 178 allowing it to move without excessive friction along the beam 175. The carriage 177 carries a tongue 170 associated with two studs 171 and 171 ' it allows to connect electrically when a chain wire 101 comes to bear against its lower surface. The method of the invention consists in placing the carriage 177 successively above each chain wire and in raising this chain wire until it exerts on the tongue 170 an effort sufficient to close the electrical circuit which comprises pads 171 and 171 ′, which has the effect of transmitting, via an electrical connection 114, a signal S ₂ , corresponding to this detection, to a unit 110 of the type of unit 10 of the first embodiment. This signal S ₂ is then processed as in the first and second embodiments.

The carriage 177 is equipped with an extension 182 intended to cooperate with chain wires other than the one whose displacement is to be measured. This extension 182 is provided with two surfaces 182 a and 182 b forming, for one, a ramp and, for the other, a stop as shown in the explanations which follow. When you want to move the carriage 177 from the right to the left of Figure 4, there is exerted on some chain son 101 'a tensile force upwards, so that they come to bear against the ramp 182 a , their forces F ₃ exerted on this ramp being transformed into a force directed to the left of FIG. 4, as represented by the arrows F ₃ . A second group of chain wires 101 '' is also raised so that it forms a stop for the advance movement of the extension 182 under the effect of the forces F ₃ by pressing the surface 182 b against them- same. When it is desired to advance the carriage 177 in the direction of arrow F ₄ , the wires 101 '' are lowered and a new group of wires 101 'is raised.

Of course, the geometry of the extension 182 can be adapted according to the direction of movement of the carriage 177.

The invention is also applicable to the case where a single actuator allows to move several beams, for example at case of a Jacquard type loom intended to form a fabric with repetitive patterns across the width. In this case accuracy obtained is less, because the beams associated with a single actuator is not adjusted between them. These are adjusted in groups between the different actuators by detecting, for example, the position of the chain wire the highest and the position of the lowest chain wire when they successively reach a position predetermined from a low position. In this case, two actuator control parameter values are selected, these values each corresponding to the first or the last wire reaching this position. The selected value for the first wire is used to determine neutral bottom of the heddle path associated with the actuator because this position determines the internal envelope of the crowd in low position. In the same way, the value of the parameter selected for the last wire reaching the position predetermined ascent is used to determine the top dead center position of the rails associated with this group of wires, because this position is determined by the lower envelope of the high crowd. This process therefore makes it possible to obtain a optimized opening of the crowd, including in the case of control of several wires with a single actuator.

According to a variant, one can plan to establish an average between the values of the parameters selected for the wire the highest and the lowest wire, this mean value being used as a reference value for actuator control corresponding.

Whatever the variant, it creates a control loop between means 20, 21, 70, 71, 170 or 171, detecting the position of the chain wires and the means 10, 60 or 110 for controlling the actuators. This loop allows to control the movement of the chain son with a great precision.

According to a variant not shown of the invention, the transmission of the signal S ₂ to the control unit 10, 60, 110 or equivalent can take place by a link other than an electric wire, provided that it intervenes in time real.

Whatever the embodiment considered, the means sensor, 20, 21 or equivalent, can be mounted so removable on the loom and, in particular, be dismantled after equalization to be used in other trades.

The invention is applicable to weaving looms equipped electric actuators controlled in open loop or closed, rotary or linear.

Thanks to the invention, the positioning of a loom harness can be carried out automatically and with great precision, so that the heddle travel can be optimized by reducing the difference between the high positions P ₁ and low P ₂ of their stroke, that is to say the opening of the crowd, so that a loom incorporating a device as described above can operate at very high speed and with better efficiency.

The invention is also applicable to trades equipped dobby, detecting the movement of warp threads associated with a frame then being made in one operation, like in the case of a Jacquard loom with multiple patterns.

Claims (10)

Device for positioning the warp threads (1; 51; 101) of a weaving loom, controlled for the formation of the crowd by electric actuators (6; 56), comprising a first means (20; 21; 70; 71 ; 170; 171; 171 '), common to the wires driven by different actuators, for detecting the passage of at least one chain wire in a predetermined position (P ₀ ) and a second means (10; 60; 110) for determining of the value ( ₀ ) of a parameter () for controlling the corresponding actuator during the passage of a wire in said position. Device according to claim 1, characterized in that that said first means is a detection assembly (20; 21) fixed to a frame of the loom and comprising a source (20) emission of a wave signal (22) and a cell (21) arranged opposite to said source with respect to the wires of chain and able to detect a variation of said wave signal. Device according to claim 2, characterized in that that said source is an emitter (20) of a laser beam (22), said cell (21) being able to detect a variation intensity of said beam which occurs when one of said chain son (1) interferes with the laser beam. Device according to claim 1, characterized in that said first means comprises a filiform sensor (70) arranged in a direction (F ₂ ) generally parallel to the weft threads (74) of the loom. Device according to claim 1, characterized in that that said first means comprises a carriage (177) movable on along a support (175) extending in a generally direction parallel to the weft threads of the loom, said carriage being equipped with a contact sensor (170) capable of cooperating selectively with one of the sons of the chain. Device according to claim 5, characterized in that said carriage (177) is integral with an extension (182) capable of coming into contact with certain chain wires (101 ', 101'') of the trade, the contacts between the wires chain and said extension being capable of generating a force (F ₃ ) of movement (F ₄ ) of said carriage on said support. Weaving loom equipped with a device according to one of the previous claims. Method for positioning the warp threads (1; 51; 101) of a weaving loom, controlled for the formation of the crowd by electric actuators (6; 56), characterized in that it consists in: moving at least one chain wire (1; 51; 101) by means of the actuator (6; 56) associated therewith; detecting (S ₂ ) the passage of said chain wire in a predetermined position (P ₀ ); select the value of a parameter () for controlling said actuator during the passage of said wire in said position and use the selected value ( ₀ ) as a reference value for the control of said actuator. Method according to claim 8, characterized in that it consists in using the selected value ( ₀ ) of said parameter for the determination of at least one set value of said parameter corresponding to at least one particular position of movement of said wire (1 ) generated by said actuator (6). Method according to one of claims 8 or 9, characterized in that it consists in moving several chain wires with a single actuator, in detecting the passage of at least one wire in said predetermined position (P _o ) and in using the selected value ( ₀ ) of said parameter () for said at least one wire for controlling the actuator.

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