EP0674030B1 - Procedure for the production of chenille yarn - Google Patents

Abstract

Produce chenille yarns, the control phases occur in a closed loop. The motor speed is taken at the time by at least one speed transducer (T) to give an electric signal (ST) of a set amplitude applicable to the current speed. The signal amplitude is compared with a reference signal (R) of constant amplitude, set at the required motor function speed. The difference between the signal (ST,R) amplitudes is converted into an error signal (E), to be converted into a signal with a frequency proportionally variable to the error signal (E) amplitude. The converted signal (C) is fed to a wave circuit (1) to change the constant voltage to a voltage value and frequency as a function of the error signal (E) amplitude. The wave circuit output signal (U) sets the motor to give an automatic operational speed instantly, according to the working.

Description

The subject of the present invention is a method for the production of chenille yarn.

It is known that a chenille yarn consists of two tying threads which are twisted so suitable for engaging ends of an effect thread. For this purpose, track machines include at least one wire formation group, with a "caliber" for winding and sizing effect thread, a blade for cutting the ends of effect thread, two training rollers with corresponding counter rollers for advancement binding threads with the ends of the effect thread and means for twisting the binding threads with the ends of effect wire interposed.

A problem particularly felt in the chenille yarn production sector is that of achieving high production, consistently high reliability, low cost and with the minimum of supervision on the part of the operator.

We also know, from document EP-A1-260206, a machine for producing threads fantasy, with several training groups of son, in which each group includes several rotary members, each of which is slaved to a corresponding electric motor, for feeding, training and assembling different threads intended to form the fancy thread and for the collection of the wire thus produced. Each machine motor is slaved to a unit programmable microprocessor control unit, according to a open diagram comprising several branches or unidirectional unit connection lines central with the different motors and a known frequency signal generator and predetermined, wherein, on each of said lines, upstream of the respective engine, is predisposed a frequency divider which is slaved to the aforementioned generator to vary the frequency of the respective output signal according to a report programmed according to the fancy effect desired: said frequency divider being connected, downstream, with a converter supplied with current continuous to control the corresponding motor in line. In this way, the speed of operation of each motor is set to varying, each time, on each line, depending of the program, the division report of the frequency of the signal emitted by the generator, and sending the respective line converter the control signal thus obtained; the different programmed frequency ratios determine the operating speed of line motors respective.

But this known machine is not intended expressly to the production of chenille yarn which must constantly present the same structural features. The open system of driving the line motors of this known machine does not, in fact, allow active control and automatic speed regulation of respective operation according to engine load conditions, variable in the time, so the reliability of each line of steering, that is to say the constancy of the speed output of the engines of each training unit of the wire, is closely dependent on that of Respective signal processing bodies the central unit and the generator of the sample signals, these organs, being arranged from the point functional view in cascade on each line, subsequently reduce the reliability of all. Therefore, this known system does not can be used almost exclusively that in the textile industry sectors in which it is not necessary to obtain a constant operating precision, as in the case of fancy yarns, when it turns out not usefully useful in all other cases where we want to obtain wires quality complexes and features high and constant structural, as is the case of chenille yarn.

Document EP-A-502828 discloses a process for the production of chenille yarn according to the first part of claim 1 of the this request.

In addition, by document EP-A-318144, we know a process for filling yarns.

The main object of the present invention is to carry out a process for the production of yarn track which allows to obtain, automatically, the maximum and constant quality level of the yarn and, in at the same time, high production and very economic.

This result has been achieved in accordance with the invention, by adopting a method for the production of chenille yarn in a machine with a or more wire formation groups, including, for each training unit, the winding and sizing phases of a wire effect, cutting the effect thread into sections of predetermined length, two-wire feed of binding and training these sons with sections of the effect yarn and twist of the yarns binding with the sections of the interposed effect thread, through several operational bodies correspondents, each of which operated separately by a corresponding electric motor, and which includes, for each engine of each unit of caterpillar formation, the following phases in closed loop circuit: read the speed of motor operation by means of a transducer speed to generate an electrical signal predetermined amplitude as a function of speed thus noted; compare the amplitude of said signal thus generated with that of a reference signal constant amplitude: the amplitude of said signal reference being known and predetermined according to the desired engine operating speed; note the difference between the amplitudes of thus compared signals and convert the signal error that eventually derives from it into a signal whose frequency is proportionally variable the amplitude of this error signal; feed a inverter circuit with the signal thus converted, from so as to transform the DC voltage respective supply of an alternating voltage of predetermined value and frequency depending on the magnitude of the error found; control the motor with the output signal from said inverter circuit, so as to adjust, i.e. instantly and automatically adapt the respective operational speed over that of work, constant, predetermined.

The advantages obtained thanks to the present invention basically consist of what is possible to achieve a high production of chenille yarn of very high and consistent quality, so automatic, reliable and economical; in that it is possible to control at any time, the speed output of each motor member of the machine, and thus the quality of the wire produced; in that it is possible to adjust with extreme simplicity and speed the operating conditions of each even chenille yarn training unit individually or in predetermined groups, in depending on the variation in nature, conditions and characteristics of the wires used.

These advantages and features of this invention as well as others will be more and better understood by each person skilled in the art in the light of the description which follows and using the attached drawings given by way of example practice of the invention, but not to consider in the limiting sense; drawings in which: Fig. 1 shows the partial side view and schematic of a machine for chenille yarn, in which is represented a training unit of the chenille yarn, with three motors; Fig. 2 represents the functional block diagram of a circuit for implementing the method for chenille yarn production according to the invention, applicable to the machine of FIG. 1.

• relever la vitesse instantanée du moteur au moyen d'un transducteur de vitesse (T) correspondant pour générer un signal électrique (ST) d'amplitude prédéterminée en fonction de la vitesse ainsi relevée;
• comparer l'amplitude dudit signal ainsi généré avec celle d'un signal de référence (R) d'amplitude constante: l'amplitude dudit signal de référence étant connue et prédéterminée en fonction de la vitesse de fonctionnement désirée du moteur;
• relever la différence entre les amplitudes des signaux (ST, R) ainsi comparés et convertir le signal d'erreur (E) qui en dérive éventuellement en un signal dont la fréquence est variable proportionnellement à l'amplitude de ce signal d'erreur (E);
• alimenter un circuit onduleur (I) avec le signal (C) ainsi converti, de manière à transformer la tension continue respective d'alimentation en une tension alternative de valeur et fréquence prédéterminées en fonction de l'amplitude de l'erreur (E) relevée;
• piloter le moteur avec le signal (U) de sortie dudit circuit onduleur, de manière à régler, c'est-à-dire adapter, instantanément, de manière automatique, la vitesse opérationnelle respective, c'est-à-dire instantanée, sur celle de travail, constante, prédéterminée.

Reduced to its essential structure and with reference to the figures of the accompanying drawings, a process for the production of chenille yarn in a machine with one or more groups for forming the yarn, according to the invention, comprises, for each training unit, the winding and sizing phases of an effect yarn, cutting the effect yarn into sections of predetermined length, feeding two tying yarns and training these yarns with the sections of the effect yarn and twisting the binding threads with the sections of the interposed effect thread, by means of stretching rollers (4), a pair of driving rollers (6) and a blade (7) driven by a first motor (1), d '' a spinning head (5) actuated by a second motor (2) and a spindle (8) with weft pre-deliverer (9) actuated by a third motor (3), and comprises, for each motor (1, 2 , 3) of each track formation unit (G), the following phases in circuit closed loop:

• reading the instantaneous speed of the motor by means of a corresponding speed transducer (T) to generate an electrical signal (ST) of predetermined amplitude as a function of the speed thus recorded;
• comparing the amplitude of said signal thus generated with that of a reference signal (R) of constant amplitude: the amplitude of said reference signal being known and predetermined as a function of the desired operating speed of the motor;
• note the difference between the amplitudes of the signals (ST, R) thus compared and convert the error signal (E) which possibly derives therefrom into a signal whose frequency is variable in proportion to the amplitude of this error signal (E );
• supply an inverter circuit (I) with the signal (C) thus converted, so as to transform the respective direct supply voltage into an alternating voltage of predetermined value and frequency as a function of the magnitude of the error (E) noted ;
• control the motor with the output signal (U) of said inverter circuit, so as to adjust, that is to say, instantly, automatically, adapt the respective operational speed, that is to say instantaneous, to that of work, constant, predetermined.

Advantageously, in accordance with the invention and in reference to fig. 2 of the accompanying drawings, it is planned to amplify the output signal (ST) of the sensor (T) before comparing it with the known one and reference constant (R).

Advantageously, it is also planned to amplify said error signal (E) before carrying out its frequency transformation.

Furthermore, advantageously and with reference to the fig. 2 of the accompanying drawings, in accordance with the invention, it is intended to send said signal (C) transformed into frequency at a circuit of PWM type control upstream of the inverter circuit (I), to allow the value of the output voltage by varying the intervals of conduction and interruption means of respective switching (T1, T2, T3, T4, T5, T6).

The regularity of operation thus ensured to different motors (1, 2, 3) of each unit (G) of wire formation allows wire production high and regular quality track and constantly having the same characteristics structural. This allows, in the phases wire processing, to obtain high quality manufactured products.

• pour la transduction de la vitesse de sortie de chaque moteur, un inducteur de proximité inductif du type "pick-up", destiné à générer des impulsions de fréquence variable en fonction de la vitesse de sortie du moteur (M) correspondant et disposé sur l'axe dudit moteur. En aval du transducteur, il est possible de disposer un convertisseur D/A pour permettre la comparaison successive avec le signal de référence (R). Il va de soi qu'à la place du transducteur décrit, il est possible de prévoir n'importe quel transducteur de vitesse adapté à cette fonction, comme par exemple une dynamo tachymétrique ou un encodeur;
• pour générer le signal de référence (R), un circuit résistif, avec un potentiomètre de réglage, alimenté de façon appropriée, de manière à fournir, en sortie, un signal de tension prédéterminée, constante et correspondant à la vitesse de sortie désirée du moteur (M) correspondant;
• pour comparer le signal de référence (R) et le signal (ST) généré par le transducteur (T), un amplificateur différentiel dont la tension de sortie dépend de la différence entre celles du signal (R) et du signal (ST) respectivement.

Le circuit onduleur (I) est constitué par un groupe onduleur statique.For the practical implementation of the procedure described above, it is possible to use:

• for the transduction of the output speed of each motor, an inductive proximity inductor of the "pick-up" type, intended to generate pulses of variable frequency as a function of the output speed of the corresponding motor (M) and arranged on the axis of said motor. Downstream of the transducer, it is possible to have a D / A converter to allow successive comparison with the reference signal (R). It goes without saying that instead of the transducer described, it is possible to provide any speed transducer adapted to this function, such as for example a tachometric dynamo or an encoder;
• to generate the reference signal (R), a resistive circuit, with an adjustment potentiometer, supplied in an appropriate manner, so as to provide, at output, a signal of predetermined voltage, constant and corresponding to the desired output speed of the motor (M) corresponding;
• to compare the reference signal (R) and the signal (ST) generated by the transducer (T), a differential amplifier whose output voltage depends on the difference between those of the signal (R) and the signal (ST) respectively.

The inverter circuit (I) consists of a static inverter group.

Claims (4)

1. Procedure for the production of chenille yarn in a machine provided with one or more yarn forming groups, comprising, for each of said groups, the steps of winding and dimensioning a fuzzy yarn, cutting the fuzzy yarn into stretches having a predetermined length, supplying two interweaving threads and driving them alongh with the lengths of fuzzy thread and operating the twist of the interweaving threads, with the lengths of fuzzy threads therebetween, by means of a cylinder (4), a pair of draw cylinders (6) and a blade (7), all them being operated by a first motor (1), of a threading head (5) operated by a second motor (2) and of a spindle (8) with weft feeder (9) operated by a third motor (3), comprising, for each motor (1, 2, 3) of each chenille-forming unit or group (G), the following steps in a closed loop circuit:

   measuring the instantaneous speed of the motor by means of a corresponding speed transducer (T) for generating an electrical signal (ST) having a predetermined amplitude according to thus measured speed;

   comparing the amplitude of the thus generated signal with the constant amplitude of a reference signal (R) : the amplitude of said reference signal being known and preset in relation to the desired operating speed of the motor;

   measuring the difference between the amplitudes of the electrical signal and reference signal (ST, R) and converting the derived error signal (E), if any, into a signal whose frequency varies proportionally to the amplitude of the error signal (E);

   feeding an inverter circuit (I) with the thus converted signal (C), so as to transform the respective direct supply voltage into an alternate voltage having preset level and frequency related to the measured error signal (E);

   driving the motor by the output circuit signal (U) from said inverter circuit, so as to instantaneously adjust, that is, automatically relate, the relevant operating speed to the preset and constant working speed.
2. Procedure according to claim 1, wherein said electrical signal (ST) is amplified on output from the sensor (T) before comparing it with the known and constant reference signal (R).
3. Procedure according to claim 1, wherein said error signal (E) is amplified before operating the frequency transformation thereof.
4. Procedure according to claim 1, wherein said frequency-transformed signal (C) is delivered to a control circuit of PWM type upstream of the inverter circuit (I), to allow for varying the output voltage value by varying the conductive and locking intervals of the respective switching means (T1, T2, T3, T4, T5, T6).

Images