Abstract:
The aim of the invention is to create a method that allows a previously produced fancy yarn to be reproduced. Said aim is achieved by a method in which a model fancy yarn is first guided through a sensor device for measuring purposes, the diameter of the model fancy yarn is continuously measured using the sensor device, the measured diameter values are evaluated, and the formation of the effect of the model fancy yarn is determined therefrom. Spinning settings are generated from the data representing the formation of the effect, and said spinning settings, which are based on the set of data, are used for producing a fancy yarn.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of German patent application 10348689.5, filed Oct. 16, 2003, herein incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a method for the production of a fancy yarn, which corresponds to an existing model fancy yarn and a device for use in producing the same.  
         [0003]     A yarn in which thick locations are present with predetermined larger diameters and with predetermined lengths, the so-called effects, is called a fancy yarn, also referred to as a novelty yarn or an effect yarn. The yarn sections located in between, with a smaller diameter, in other words the effect-free sections, are called webs. Fancy yarns are becoming more and more important. Areas of application are, for example, denims, materials for casual clothing and home textiles.  
         [0004]     Fancy yarns can also be produced on rotor spinning machines. In this case, the fiber feed to the opening roller of the rotor spinning mechanism is changed, for example, in that the speed of the draw-in rollers is varied. For this purpose, mechanical gearings are activated, which drive shafts extending along the length of the machine. These draw-in rollers are made to rotate by means of the shafts. However, owing to the large mass of the moved parts of a drive system of this type and the gearing play, an exact and abrupt change in the yarn thickness at the beginning and end of an effect cannot be achieved, or only with difficulty. The speed during the spinning of fancy yarn optionally has to be sharply reduced when spinning fancy yarn compared to the speed when spinning effect-free yarn.  
         [0005]     German Patent Publication DE 44 04 503 A1 describes a rotor spinning machine, in which each draw-in roller with its drive shaft is directly connected to an associated stepping motor. Each stepping motor can be activated via an activation unit. Random speed changes of the draw-in of the sliver (also known as a sliver) can be generated with a random generator. A fancy yarn with predetermined effects cannot be produced with this known rotor spinning machine. The disadvantage of yarns produced by means of a random generator is primarily that patterns are unintentionally produced in the textile surface by the random production.  
         [0006]     However, in the meantime programs for controlling ring or rotor spinning machines, in particular their supply cylinders have been developed, with which effects can be adjusted in a targeted manner (see for example German Patent Publication DE 40 41 301 A1).  
         [0007]     It is known to store the effect data of previously produced fancy yarns, in order to be able to produce a yarn again with the same effects at a later instant. However, if a fancy yarn exists, which was produced, for example with a ring spinning machine but is now to be produced on a rotor spinning machine with a substantially similar effect specification, the effect and setting data available cannot be directly transferred.  
         [0008]     The effect data includes, in particular, the effect lengths, effect diameters, the effect frequency and the respective effect-free thread length or web length.  
       SUMMARY OF THE INVENTION  
       [0009]     The object of the invention is to propose a method and a device, which make the reproducibility of a previously produced fancy yarn possible.  
         [0010]     This object is achieved with a method for producing a fancy yarn, which corresponds to an existing model fancy yarn. Initially the model fancy yarn is guided through a measuring mechanism for measuring, and at least one of the parameters of diameter and mass of the model fancy yarn is continuously measured by means of the measuring mechanism. The measured values are evaluated and the effect formation of the model fancy yarn is determined therefrom from the effect regions and webs located in between. A data set is formed from the data representing the effect formation. Spinning settings are generated, based on the previously formed data set and a fancy yarn is produced with these spinning setting.  
         [0011]     The invention further provides a device for carrying out the above-described method and comprises a measuring mechanism for determining at least one parameter of diameter and mass of a model fancy yarn, an evaluation mechanism which determines the effect data of the model fancy yarn from the measured values, a yarn design unit which generates the data required for spinning on a spinning machine, in particular a rotor spinning machine, from the effect data by means of a yarn design software, and control mechanisms for controlling the drives of the spinning machine based on the data transmitted by the yarn design unit.  
         [0012]     By means of the method according to the invention, all the essential data for the further production of a fancy yarn is collected and brought into a form which makes it possible to produce the presented yarn, regardless of what type of machine it was previously produced on, for example even to produce it on a rotor spinning machine, with the characteristic effect structure substantially being recognizable again.  
         [0013]     Further advantageous configurations and embodiments of the invention reside in the details of determining the effect formation, which result from the transverse dimension values which have been supplied by a measuring mechanism. The important factor above all is to determine regularities in the repetition of effect lengths and dimensions including their repeat length and to eliminate effect-independent irregularities. Only thereby is a reproduction of the model effect possible.  
         [0014]     The yarn produced may also be measured wherein the effect formation of the yarn produced is determined and compared with the effect formation of the model fancy yarn, and the spinning settings are changed until an adequate agreement between the effect formation of the yarn produced and the effect formation of the model fancy yarn is achieved. If a check on the effect achieved is carried out in this manner, an adjustment may take place until adequate agreement is achieved with the original yarn. In other words, it is possible according to the present invention to check, in a plurality of cycles, the result of the respective change in parameters and to initiate a change again. In this manner, the yarn can very closely approach the original yarn. Checking of the agreement may take place either by statistical detection, in particular detection of the effects by tables, in other words, their thickness, length and distribution or else their visual presentation, as is known, for example, by means of the Oasys® system from Zweigle. In the simplest case, the yarns may be directly compared visually.  
         [0015]     The data set of the spinning settings for producing fancy yarn may be stored after completed adjustment, with identification ensuring retrieval. The reproducibility of this yarn is very good owing to storage of such data after adjustment.  
         [0016]     The spinning settings which, apart from the directly effect-related data, vary with the changing transverse dimension of the yarn, also contain further data relating to the basic adjustment of the spinning machine, such as the rotor speed, opening cylinder speed and selection of the spinning means. Such data may be stored on a storage medium for further production of the fancy yarn. Such data may be provided with addresses and addressed to the respective control units provided for the corresponding control operations. By this adaptation to the original yarn, spinning settings also have to be taken into account that relate to the base setting of the machine, which do not vary like the directly effect-related data with the varying transverse dimension of the yarn. Thus, for example, the thickness of the yarn section may be changed by changing the twist factor. The combing out power of the opening roller influencing the effect is determined both by the type of fittings and the peripheral speed of the opening roller.  
         [0017]     The data to then be resupplied to the rotor spinning machine is effective for various control mechanisms. Accordingly, the data contains addresses of control mechanisms, for which it is intended. On downloading, this leads to the intended allocation of the data.  
         [0018]     In this case, data is also included, which is merely brought to a display of the central control mechanism for display. This relates, in particular to data, which cannot be converted by the machine itself. An example is the necessary number of spinning means.  
         [0019]     The device according to the invention may further comprise mechanisms mounted in front of the control mechanisms, with at least, however, the measuring mechanism being configured as separate mechanisms. The separate mechanisms are coupled to the control mechanisms via connections. Thus, this plurality of mechanisms are alternatively connected to the spinning machine or are operated separately from one another. In either case, these mechanisms are alternatively connected via data lines to the control mechanisms of the spinning machine or available by means of transportable data carriers for the control mechanisms. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The invention will be described with the aid of a rotor spinning machine.  
         [0021]     In the drawings:  
         [0022]      FIG. 1  shows a schematic view of a spinning station,  
         [0023]      FIG. 2  shows the opening mechanism of a spinning station in a simplified schematic view, in a partial view,  
         [0024]      FIG. 3  shows a schematic view of the control, in particular of draw-in rollers of a rotor spinning machine,  
         [0025]      FIG. 4  shows a fancy yarn, which is shown by the arrangement side by side of measured values of the yarn diameter and  
         [0026]      FIG. 5  shows the schematic view of a yarn effect. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     Of the large number of spinning stations of a rotor spinning machine, a single spinning station  1  is shown in side view. At the spinning station  1  a sliver  3  is drawn by a so-called compressor  4  into the spinning box  5  of the rotor spinning mechanism from a sliver can  2 . The mechanism arranged in the spinning box  5  for separating the fibers and feeding them into the spinning rotor  6  are known from the prior art and  23  via the drive connection  29 . The stepping motor  23  can be activated by the line  24 . The direction of rotation of the opening roller  28  is indicated by the arrow  30 .  
         [0028]     The schematic structure of a draw-in roller control is shown schematically in  FIG. 3 .  
         [0029]     The measuring mechanism  31  described in the present example measures the diameters of the presented yarn. Alternatively, the yarn mass could be determined, for example, by means of a capacitive sensor instead of an optical sensor. In determining the yarn mass, which is generally used as a basis for the determination of the yarn fineness, the mass of a yarn section passing the measuring region is measured, while in an optical measurement, an average diameter value is determined inside the measuring region. Both measurements are equally suitable for evaluation of the effect formation. In the present example, however, the invention is described with the aid of the diameter determination.  
         [0030]     Initially, the original yarn is supplied to the schematically shown measuring mechanism  31  which detects the measured diameters in relation to the thread length running through and transmits this data to an evaluation mechanism  32 ′ of a yarn design unit  32 . The transmission is indicated by the arrow  33 . The effect data is formed in the evaluation mechanism  32 A from the measured values. The evaluation mechanism may also be combined with the measuring mechanism  31  or may be formed by a separate mechanism. The formation of the effect data is described below in conjunction with the  FIGS. 4 and 5 .  
         [0031]     The data required for spinning on a rotor spinning machine is generated by means of yarn design software in the yarn design unit  32 . This data includes both the directly effect-related data, which varies with the changing diameter of the yarn and further data relating to the basic setting of the rotor spinning machine. This is, for example, the rotor, draw-off roller and opening roller speed and the selection of the spinning means. While the latter are preferably retrieved from a table, the speeds have to be determined by corresponding algorithms. These algorithms are based on known connections. This involves, for example, the determination of the drawing from the ratio of the speeds of the take-off rollers to the speed of the take-in rollers, or of the rotations per meter from the rotor speed to the take-off speed and the constriction of the fiber assembly connected thereto.  
         [0032]     The data generated in the yarn design unit  32  is transmitted via a data bus, the CAN-BUS  34  here, to a central control mechanism  35  of the rotor spinning machine. The transmission may also alternatively take place using transportable data carriers, such as for example a compact flash card.  
         [0033]     The central control mechanism  35  is connected to the central computer  22  via the data line  36 .  
         [0034]     A control mechanism  25  comprises the control of, for example, 24 stepping motors  23  of the respective take-in rollers  27  via lines  24 . All 24 spinning stations are constructed in the same manner. A control card  40  is connected on the control mechanism  25  by means of a connection device  39 .  
         [0035]     The data required to produce fancy yarn for controlling the stepping motors  23  is transmitted to the control card  40  via a can bus  41  by the central control mechanism  35 . The control card  40 , to produce fancy yarn, converts the data about thickness and length of the effects and webs, with adaptation to the conventional spinning settings, into control data for the stepping motors  23  to generate the rotational movement of the draw-in rollers  27 . The data required for the control of the stepping motors of the draw-in rollers is transmitted via a can bus  42  as a continuation of the can bus  41  to further control cards, not shown, which are connected to control mechanisms of further sections of the rotor spinning machine. One of the further control mechanisms is shown by dashed lines. The further control mechanisms are constructed like the control mechanism  25 , have the same connection device and the same connected control card. Each further control mechanism controls the spinning stations of a section of the rotor spinning machine, in each case.  
         [0036]     If a stepping motor  23  is activated in such a way that it runs more quickly compared to the base speed, the draw-in roller  27  transports more fiber material to the opening roller  28 . This has the result that per time unit more fiber material arrives in the rotor  6  and the thread spun becomes thicker. The length of the thick location depends on the duration of the increased fiber supply. The diameter of the thick location depends on the speed of the stepping motor  23  or the draw-in roller  27 .  
         [0037]     The control mechanism  25  is then activated via the line  43  by the central computer  22 , moreover, when it is input via control commands whether the control mechanism  25  alternatively controls the production of fancy yarn or the production of effect-free yarn.  
         [0038]     By means of one of the sensors  12 , or a separate sensor, which is not drawn in here, the freshly spun yarn is measured out and the measured values transmitted to the yarn design unit  32  which is also provided with a display, not shown, in order to reproduce the current fancy yarn. If the appearance or the statistical description of the freshly spun yarn does not correspond to the original yarn, further changes have to be made. These changes may consist in changing the effect parameters which are input in the yarn design unit and in the change of further machine parameters, which are generally to be input at the central computer  22 . For this, control connections  44  are available at the central computer, which may lead, for example, to a control mechanism  45  for the draw-in rollers  11  or  46  for the spinning rotors  6 , the control mechanisms  45  and  46  being formed, for example, by frequency converters. A display  47  at the central computer also displays the spinning means selected which have a not inconsiderable influence on the formation of the effects.  
         [0039]      FIG. 4  shows the view of the yarn profile of the fancy yarn as an arrangement side by side of measured values. Effects  48  and webs  49  can be seen but the beginning and end of the effects  48  and the effect thickness or the effect diameter DE and the web thickness or the web diameter DST cannot be clearly seen and therefore cannot be seen adequately.  
         [0040]     The measuring mechanism  31  registers the yarn diameter D in each case after 2 mm of yarn length. A cycle step represents a measuring length of 2 mm yarn. In the view of  FIG. 5 , the yarn diameter D is shown in a percentage over the yarn length LG as a curve  50 . The curve  50  represents, in the view of  FIG. 5 , starting from the left up to point  51 , the yarn diameter DST. From the point  51 , the curve  50  rises and at point  55  passes the value of the limit diameter D GR . At point  53 , the predetermined yarn length L V  has been covered since reaching the point  52 . After a diameter increase of 15% is registered at point  52 , and the exceeding of the yarn diameter G GR  lasts over the predetermined length L V , for example six cycles or 12 mm, the point  52  is defined as the beginning of the effect. The curve  50  falls below the limit diameter D GR  at the point  54 . The falling below lasts up to the point  55  and therefore over the predetermined yarn length L V . The point  54  is therefore defined as the end of the effect. The effect length L E  is determined from the beginning and end of the effect between point  52  and point  54 . An arithmetic average value is formed from the four largest diameters  56  inside the effect. The information about the effect diameter is therefore most substantially independent of the natural diameter variations in the effect region as a result. This arithmetic average value is defined as the effect diameter D E .  
         [0041]     The regions between the effects defined in this way are the webs with the basic diameter of the yarn. To determine the repeat, a number of consecutive effects and webs is initially compared with the same number of subsequent effects and webs. This number should advantageously lie below the expected repeat length. The measure of agreement contains information as to whether the sequence of effects and webs on which the comparison is based corresponds to the repeat length. For this purpose the number of effects/webs to be included in the comparison is to be successively increased. If on reaching a certain number of effects/webs a maximum is produced, which differs significantly from the adjacent values, this value corresponds to the repeat length. The last prerequisite for reproduction of the model yarn therefore exists.