Spinning method and spinning frame

Abstract: A spinning method and a spinning frame are provided which yield spun yarn (13) on an industrial scale while providing the comfortable feel of a hand-spun yarn. In a spinning frame (1), rovings (11) are drafted in a controlled manner using signals derived from a melody or other sound having a 1/f fluctuation to yield the spun yarn (13) in which the diameter varies with the 1/f fluctuation thus providing a natural, comfortable feel.

Description: The invention relates to yarn spinning, in particular to a spinning method and a spinning frame for such a spinning method. The market has a demand for a high-quality machine-spun yarn, having the feel of a natural variation of coarseness and fineness, thereby imitating the texture and appearance of hand-spun yarn. In the past, yarns having this variation in texture have been the subject of various studies. For example, JP-A-62-170 542 discloses a spun yarn in which coarse yarn portions and fine yarn portions are mixed at random. There, the front roller of a roller-draft type spinning frame is coupled directly to a servo motor, the speed of which can be freely varied by a DC voltage signal. In that conventional spinning frame, a computer output controls the rotary speed of the front roller to vary appropriately, causing the draft factor to change throughout spinning, thereby producing a yarn of random thickness. Moreover, the publication JP-A-63-112 739 discloses a spun yarn obtained by independently driving the middle roller of the draft rollers in a ring spinning frame, using a variable-speed motor and varying its speed at random time intervals. The United States Patent US-A-3,868,496 discloses a control mechanism for producing random-mike effects in fabrics. A control circuit produces alternate ON and OFF signals to produce a slub on a yarn or a thread at random times. The cloth or fabric woven from such yarn gives a random-like appearance. The circuitry automatically causes the distance between the slubs to vary within a range defined previously between a minimum and maximum value. The actual length is then determined in a pseudo random manner. Hence, conventional machine spinning produces yarns with an irregular feel by varying the yarn diameter or the spacing of slubs at random. However, this randomness produces an artificial texture with very little of the natural feel of a hand-spun yarn, and articles made thereof are not very comfortable for a wearer. The object underlying the present invention is to provide a spinning method and a spinning frame for producing yarns having a natural feeling of comfort to human beings. According to the present invention, a spinning method and a spinning frame are provided as defined in claims 1,3 and 4. One advantage of the present invention resides in that yarns are provided in which the diameter does not vary randomly, rather the variations have a correlation, in particular a 1/f fluctuation. Using the spinning method and the spinning frame according to one embodiment, yarns are provided in which the 1/f fluctuation corresponds to a melody or sound. The spinning method and the spinning frame according to the invention are capable of spinning yarns having a natural, irregular feel on an industrial scale. In the present application, the expression "1/f fluctuation" is defined and understood as a power spectrum of the frequency component f, and it is proportional to 1/f k , wherein k is approximately 1. The invention will be explained in more detail below by means of preferred embodiments and with reference to the accompanying drawings, wherein Fig. 1 shows an overview diagram of the principal components of a spinning frame in one embodiment; Fig. 2 is a block diagram of the drive system for motors provided in the spinning frame; Fig. 3 shows a portion of a melody which produces a 1/f fluctuation; Fig. 4 shows a yarn drafted using the melody according to Fig. 3. The technique for spinning yarn involves various steps. At first, a mass of short fibers, for example raw cotton, is blended, and then the fibers are aligned in a single direction. A number of the fibers are bundled into cordlike slivers and then drafted. These operations are repeated, and thereafter a very slight twist is imparted to form rovings 11. Next, these rovings 11 are further drafted by a spinning frame 1, and thereafter a twist is imparted to yield spun yarn 13. For the rovings 11, various fibers and blends thereof can be used, for example natural fibers such as cotton or flax, regenerated cellulose fibers such as rayon or cuprammonium rayon, semi-synthetic fibers such as acetate or synthetic fibers such as polyester. The present invention concentrates on the drafting process when spinning these rovings 11 into the yarn 13. Drafting with a 1/f fluctuation ultimately causes the thickness of the yarn 13 to vary with a 1/f fluctuation. As a result, it is possible to manufacture yarns in large quantities using mechanical equipment having a feel similar to yarn spun manually. Spinning Frame Fig. 1 of the drawings discloses a simplified diagram of the spinning frame 1 as an embodiment of the present invention, wherein the spinning frame 1 is a device to draft the rovings 11 and, by imparting a twist, to spin it into yarn 13. As shown in Fig. 1, the spinning frame 1 comprises a plurality of motors, including a back motor 21, an apron motor 22, a front motor 23 and a spindle motor 24, each of which can be independently controlled. The back motor 21 is used to drive a back roller 31. The rotational speed of the back roller 31 can be determined, for example, by imparting a prescribed rotational speed to the back roller 31 via a belt 51 and gears 52, and by adjusting the size and the number of the gears 52. Moreover, the rotational speed of the back roller 31 can be adjusted arbitrarily by controlling the back motor 21. In a similar manner, the apron roller 32 and the front roller 33 can be independently controlled, and the rotational speed of the apron roller 32 and the front roller 33 can be adjusted arbitrarily. The rotational speed of the apron roller 32 and the front roller 33 can also be adjusted by using a belt 51 and gears 52. Moreover, an arbitrary rotational speed can be imparted to a spindle 41 by rotating a tin roller 34 using the spindle motor 24. These motors can also be used in common, where necessary, and the rotational speed of the rollers can be adjusted using speed converters such as belts 51 and/or gears 52. Back Roller, Apron Roller and Front Roller The back roller 31 has a prescribed rotational speed and pinches the rovings 11 to draw them out. The drawing speed of the rovings 11 is determined by the diameter and the rotational speed of the back roller 31. In a similar manner, the apron roller 32 draws out a fiber bundle 12 fed from the back roller 31. A rubber apron is arranged to rotate on the periphery of the apron roller 32, and by applying pressure to the fiber bundle 12 over a large surface area and holding the fiber bundle stable, draws it out. By adopting a drawing speed for the apron roller 32 that is larger than the drawing speed of the back roller 31, the rovings 11 are drafted or attenuated by a factor of, for example, 1.2 to 2. In other words, by drafting the rovings 11 between the back roller 31 and the apron roller 32, the fibers of the rovings 11 slide and rub against each other and are formed into a fiber bundle which is finer than the rovings 11, being made 1.2 to 2 times longer. In a similar manner, the front roller 33 also draws out the fiber bundle 12 fed from the apron roller 32. Its drawing speed is set to be greater than the drawing speed of the apron roller 32. By setting the drawing speed, for example to be 20 times faster than that of the apron roller 32, the drafting will form a fiber bundle 12 that is 20 times longer than the original. In other words, the diameter of the fiber bundle 12 will become thinner. Over the entire spinning frame 1, by the time the rovings 11 are drawn out from the back roller 31 and the fiber bundle 12 is brought out from the front roller 33, the degree of attenuation would be 30 to 40 fold. Spindles The rotation of the respective spindles 41 imparts a twist to the fiber bundle 12 fed from the front roller 33 which is then wound as yarn 13 onto bobbins. In reality, the degree of twist is set for the yarn 13 to be able to withstand downstream processes, generally weaving or knitting and to affect the hand of finished woven fabrics or knitted goods. The degree of twist can be expressed by a twist coefficient as indicated in the following equation (1): K = T Ne wherein K = twist coefficient T = twist count and Ne = yarn count. For yarns of the same yarn count, the twist count increases as the twist coefficient increases, forming yarn with a hard hand, and the twist count decreases as the twist coefficient decreases, forming a bulky yarn with soft hand. In a typical case, the twist coefficient will be 2.5 to 4.5 To obtain yarns of the same hand but with different yarn counts, the twist coefficient is set to be constant, and the twist count is set to correspond to the yarn count. The twist is determined by the length of the fiber bundle 12 fed from the front roller 33 and by the number of twists imparted over the length. Therefore, the twist can be modified by keeping either parameter constant and varying the other. To increase the twist at the same yarn count, the feed from front roller 33 can be kept constant while increasing the rotation of the spindle 41. On the other hand, the rotation of the spindle 41 can be kept constant while reducing all feed from the back roller 31, the apron roller 32 and the front roller 33. The same result will be achieved in either case. 1/f Fluctuation The present inventor has discovered that a 1/f fluctuation would impart a particularly comfortable feel to human beings. The results were published in a paper entitled "Bioinformation and 1/f Fluctuation", Applied Physics, 1985, pp. 429 to 435, and in another paper entitled "Biocontrol and 1/f Fluctuation", Journal of Japan. Soc. of Precision Machinery, Vol. 50, No.6, 1984, pp. 109-114. The abstract of these papers reads as follows: "The 1/f fluctuation provides a comfortable feeling to human beings; the reason is that the variations in the basic rhythm of the human body have a 1/f spectrum. From another perspective, the human body eventually becomes tired of a constant stimulation from the same source, but conversely, the body feels uncomfortable if the stimulations were to change too suddenly. Therefore, a 1/f fluctuation is a fluctuation of the right proportion between these two extremes." In addition, an excerpt from "The World of Fluctuations" by Brubachs, published by Kodansha, reads as follows: "For example, the rhythms exhibited by the human body such as heart beats, hand-clapping to music, impulse-release period of neurons, and α-rhythms observed in the brain, are all basically 1/f fluctuations. It has been shown experimentally that if a body is stimulated by a fluctuation like these biorhythmic 1/f fluctuations, it would feel comfortable." Fluctuations or variations exist in various forms throughout the natural world. The gurgling of a stream, a soft and gentle breeze, and other phenomena that impart a comfortable feeling to human beings have a 1/f fluctuation, whereas typhoons and other strong winds that impart uneasiness do not have a 1/f fluctuation. 1/f Fluctuation of Yarn In order to impart a 1/f fluctuation to the yarn 13, drafting of the fiber bundle 12 can be varied by controlling the back motor 21, the apron motor 22, the front motor 23 and the spindle motor 24, respectively. For example, the speed at which the fiber bundle 12 is taken up by the apron roller 32 can be kept constant, and the speed at which the fiber bundle 12 is taken up by the front roller 33 can be varied with a 1/f fluctuation, wherein the diameter of the drafted fiber bundle 12 will vary from thick to thin with a 1/f fluctuation. The take-up speed of the front roller 33 can be adjusted by controlling the rotational speed of the front motor 23. Accordingly, in order to impart a 1/f fluctuation to the diameter of the yarn 13, a 1/f fluctuation signal is applied to control the rotary speed of the front motor 23, wherein drafting between the apron roller 32 and the front roller 33 will cause the diameter of the yarn 13 to vary. Alternatively, rather than controlling the front motor 23, the apron motor 22 can be controlled, or both motors 22 and 23 can be controlled concurrently. Fig. 2 shows a block diagram in order to illustrate the motor control. The controller 6 receives signals from the motor speed setter 61 provided for the back motor 21, the apron motor 22, the front motor 23 and the spindle motor 24. The controller 6 also receives a signal from a 1/f fluctuation signal generator 62 and a yarn courseness variation width setter or yarn thickness setter 63. All these signals are processed by the controller 6 which supplies drive signals to drivers 64 which control the motors 21 to 24. Each motor 21 to 24 supplies a feedback signal via a corresponding speed detector 25 allowing their rotational speed to be controlled. The motor speed setter 61 sets the speed of each motor to a prescribed value. By imparting a 1/f fluctuation signal from the 1/f fluctuation signal generator 62 based upon these prescribed speed values, a 1/f fluctuation can be imparted to the rotational speed of the respective motors 21 to 24. In addition, the yarn thickness setter 63 can be set to vary the rotational speed of each motor 21 to 24, thereby setting the thickness of the yarn 13 to prescribed values, wherein a yarn with a 1/f fluctuation based on the set thicknesses, will be spun. 1/f Fluctuation Signal The 1/f fluctuation signal is determined from y 1 , y 2 , y 3 , ... formed by calculating n coefficients a 1 , a 2 , a 3 , ...a n in a sequence of random numbers x 1 , x 2 , x 3 .... Here, y j can be expressed by equation (2). It should be noted that the sequence of numerical values forming y 1 , y 2 , y 3 , ... has a 1/f spectrum. For further details, reference is made to Seitai shingou (Biological Signaling), chapter 10, "Biological Rhythms and Fluctuations", published by Corona Publishers, Ltd.. 1/f Fluctuation Signal Generator The 1/f fluctuation signal generator 62 shown in Fig. 2 operates as follows. In a first step, a sequence of random numbers is generated using, for example, a computer. In a second step, this sequence of random numbers is stored in a storage device, wherein a certain number n of coefficients is successively calculated, and then a sequence of numerical values y is obtained by a linear transformation. An example of a 1/f fluctuation obtained in this manner is shown in the following: equation (3): Sequence of numerical values = {17, 12, 15, 15, 12, 14, 12, 8, 11, 12, 9, 9, 11, 7, 5, 2, 3, 0, 6, 7, 7, 8, 6, 3, 3, 6, 6, 3, 2, 4, 2, 4, 2, 0, 5, 6, 7, 7, 5, 7, 9, 4, 1, 4, 8, 7, 5, 4, 6, 2, 0, 6, 3, 7, 8, 10, 10, 5, 5, 8, 9, 7, 11, 5, 7, 8, 10, 6, 10, 9, 10, 10, 8, 11, 13, 10, 8, 6, 7, 4, 9, 7, 8, 7, 8, 3, 5, 7, 10, 11, 8, 5, 7, 6, 3, 8, 11, 10, 12, 9, 6, 11, 12, 13, 11, 10, 6, 6, 9, 7, 6, 2, 7, 9, 4, 1, 6, 8, 11, 9, 12, 12, 11, 7, 11, 6, 3, 5, 6, 9, 11, 6, 10, 6, 5, 3, 4, 9, 7, 7, 3, 4, 5, 3, 1, 1, 2, 6, 8, 11, 8, 11, 14, 14, 10, 9, 8, 7, 7, 8, 10, 5, 6, 7, 3, 5, 7, 10, 7, 9, 11, 12, 11, 9, 10, 12, 15, 12, 11, 13, 13, 13, 15, 16, 18, 20, 17, 17, 12, 13, 16, 12, 15, 11, 12, 16, 15, 12, 14, 13, ...} This numerical sequence has a 1/f spectrum; hence it is converted into an electrical signal as a 1/f fluctuation signal and output to the motor control signal. For example, large values in the numerical sequence can be set to correspond to a high electric potential to increase the speed of the respective motor, thereby creating a longer draft. Other methods can also be employed such as a numerical control to control the rotational frequency of the respective motors using values from the numerical sequence. If the inertia of the motors and other components of the control system of the spinning frame 1 is large, drafting can also be performed by reducing the level of the 1/f fluctuation control signal as necessary. Twist Control The spindle 41 applies a twist to the fiber bundle 12 fed from the front motor 23 forming yarn 13 of suitable strength. In applying a twist to a fiber bundle 12 of uniform thickness, the strength of the twist can be controlled to have a 1/f fluctuation by applying the 1/f fluctuation signal to the rotational speed of the spindle motor 24. A similar effect can be achieved by keeping the rotation of the spindle 41 constant and keeping the rotational frequencies of the back motor 21, the apron motor 22 and the front motor 23 at a constant ratio, and then applying the same 1/f fluctuation signal concurrently to the three motors 21, 22 and 23. If on the other hand the fiber bundle 12 is drafted with a 1/f fluctuation, the rotation of the spindle 41 can be controlled to apply a stronger twist to sections of the yarn 13 of thin diameter and a weaker twist to sections of the yarn 13 of thick diameter in order to provide a uniform twist coefficient over the length of the yarn 13. In addition, since the apparent thickness of the yarn 13 varies as a function of the degree of twist, a 1/f fluctuation can be applied that will take this variation into account. In this case, both the drafting motors 21, 22 and 23 and the spindle motor 24 of the spindle 41 are controlled to impart a 1/f fluctuation over the entire drafting and twisting process. Creating a Melody Having a 1/f Fluctuation Equation (2) for a sequence of numerical values y having a 1/f sequence can be used in order to create a melody. For this purpose, the scale and the range with a lowest frequency fL and a highest frequency fU are determined. Then, a 1/f sequence y is derived, and a linear transformation is performed so that the upper and lower limits become the lowest frequency fL and the highest frequency fU, respectively. The values of the sequence y so derived are regarded as acoustic oscillation frequencies, and are substituted for the oscillation frequencies of the scale they most closely approximate. In other words, they are arranged, for example, as quarter notes, between or on the lines of a staff on music paper. Fig. 3 shows a portion of a melody derived using this method. The pitch and duration of the notes of the arranged melody are set to correspond to the rotational speed of the motor and the duration of that speed, respectively, thereby controlling the respective motor. Upon drafting the fiber bundle, the melody is expressed in the variations in the diameter of the yarn. Generating Control Signals from Sounds with 1/f Fluctuation The sound of the gurgling of a river, the music of J.S. Bach and the music of W.A. Mozart have a 1/f fluctuation. Accordingly, a recording or live performance of these sounds can be sampled at a constant interval, for example, every 25 ms, and the average frequency can be determined. One method to determine the average frequency is to count the number of times the signal of a measured frequency crosses a reference line, and then convert this count to a count per unit time. The sequence of average frequencies so obtained is mapped as musical notes, which can then be used as signals required for motor control. The relationship between music and 1/f fluctuation is described, for example, in Yuragi no sekai (The World of Fluctuation) published by Kondansha Blue Box, and Mugen, kaosu, yuragi (Infinity, Chaos and Fluctuation) published by Baifûkan. Spun Yarn A linear sequence y, a melody derived from a linear sequence y, or a melody derived from recorded signals of a live musical performance, or the gurgling of a river, is input into a 1/f fluctuation signal generator to obtain a 1/f fluctuation signal. The base speed of the motors 21, 22, 23 and 24 and the thickness of the yarn 13 are set using the motor speed setter 61 and the yarn thickness setter 63, respectively. In one example, to produce a spun yarn, the melody of Fig. 3 was input into the 1/f fluctuation signal generator 62, and the 1/f fluctuation signal so obtained was used to control the front motor 23 to spin a yarn with a 1/f fluctuation. Fig. 4 shows the yarn 13 obtained in this way after being wound on an evenness defects test panel 7. For motor control, the duration of one note in the melody was set to be equivalent to 1 meter of the yarn 13, the "la" note at 440 Hz was set to be equivalent to a thickness of yarn count 30, and the difference between the respective adjacent notes on the "do, re, mi, fa, so, la, ti, do" scale was set to be equivalent to a yarn count of 5. Under these conditions, the yarn 13 became finer with higher frequencies. In this case, the length of variable thickness of the yarn 13 between notes was on the order to several centimeters. When using the spinning method and the spinning frame according to the invention, the following advantages can be a-chieved: The diameter of the yarn 13 does not change randomly, rather the change has a distribution of a 1/f fluctuation thus imparting to the yarn 13 a feel with the natural irregularity of hand-spun yarn, which provides a special esthetic beauty and comfortable wear. Also, the 1/f fluctuation can be imparted to the twist of the yarn 13, thereby varying the texture of the yarn 13, which again provides a comfortable wear. Yarn can be spun on an industrial-scale, at low cost, but providing the natural irregular feel of hand-spun yarn. In such a method, the amount of twist can be varied as a function of the diameter of the yarn which results in a uniform twist coefficient over the length of the yarn. By expressing a 1/f fluctuation based on a melody and transforming this fluctuation into the yarn during spinning can be used in an advantageous manner in order to vary its diameter for the indicated purpose.

Claims: A method of spinning rovings (11) into yarn (13), comprising drafting fiber bundles (12) from the rovings (11) with a predetermined degree of attenuation, and thereafter twisting the respective fiber bundles (12) drafted from the rovings (11) to yield the spun yarn (13), characterized by setting the degree of attenuation in drafting to correspond to the strength of serial signals having a 1/f fluctuation and/or setting the amount of twist in twisting by serial signals having a 1/f fluctuation. The spinning method according to claim 1, characterised in that the yarn (13) is spun by applying a stronger twist to the thin portions of the fiber bundles (12) drafted from the rovings (11). A spinning frame for spinning rovings (11) into yarn (13), comprising: a back roller (31) adapted to draw rovings (11), an apron roller (32) adapted to draw a fiber bundle (12) fed from the back roller (31), a front roller (33) adapted to draw the fiber bundle (12) fed from the apron roller (32), a spindle (41) arranged to receive the fiber bundle (12) fed from the front roller (33), and a controller (6) for controlling the variable rotational speed of said rollers (31, 32, 33) and said spindle (41), characterised in that said controller (6) is adapted to set the rotational speed of the front roller (33) to be greater than that of the apron roller (32) so as to draft the fiber bundle (12) therebetween and to set the difference in drawing speed between the apron roller (32) and the front roller (33) to vary with a 1/f fluctuation, and said spindle is adapted to apply a twist to the fiber bundle (12). A spinning frame for spinning rovings (11) into yarn (13), comprising: a back roller (31) adapted to draw the rovings (11), an apron roller (32) adapted to draw a fiber bundle (12) fed from the back roller (31), a front roller (33) adapted to draw the fiber bundle (12) fed from the apron roller (32), a spindle (41) arranged to receive the fiber bundle (12) fed from the front roller (33), and a controller (6) for controlling the variable rotational speed of said rollers (31, 32, 33) and said spindle (41), characterized in that said controller (6) is adapted to set the rotational speed of the spindle (41), used to apply a twist to the fiber bundle (12), to vary with a 1/f fluctuation. The spinning frame according to claim 3 or 4, characterised in that the drawing speed of the apron roller (32) is varied to have a 1/f fluctuation, and in that yarn (13) is spun by drafting the fiber bundle (12) between the apron roller (32) and the front roller (33), and then applying a twist to the fiber bundle (12) using the spindle (41). The spinning frame according to claim 3 or 4, characterised in that the drawing speed of the front roller (33) is kept constant, and the drawing speed of the apron roller (32) is set to vary with a 1/f fluctuation, and in that yarn (13) is spun by drafting the fiber bundle (12) between the apron roller (32) and the front roller (33), and then applying a twist to the fiber bundle (12) using the spindle (41). The spinning frame according to any of claims 3 to 6, characterised in that the spindle (41) applies a strong twist to the thin portions of the fiber bundle (12) drafted between the apron roller (32) and the front roller (33). he spinning frame according to any of claims 3 to 7, characterised in that the drawing speed of the front roller (33) and the drawing duration is set to correspond to the pitch and duration, respectively, of the notes of a melody with 1/f fluctuation, and in that the fiber bundle (12) is drafted between the apron roller (32) and the front roller (33). The spinning frame according to any of claims 3 to 8, characterised in that the drawing speed of the front roller (33) is set to correspond to the average frequency of each periodic interval of a sound having a 1/f fluctuation, and in that the fiber bundle (12) is drafted between the apron roller (32) and the front roller (32).

Inventors: MURAOKA KAZUYOSHI, MUSHA TOSHIMITSU, NAKANO YASUO, NIWA YUKI, YANAI YUICHI, MURAOKA, KAZUYOSHI, MUSHA, TOSHIMITSU, NAKANO, YASUO, NIWA, YUKI, YANAI, YUICHI, MURAOKA, KAZUYOSHI, C/0 NISSHINBO INDUSTRIES INC., NAKANO, YASUO, C/O NISSHINBO INDUSTRIES, INC., NIWA, YUKI, C/O NISSHINBO INDUSTRIES, INC., YANAI, YUICHI, C/O NISSHINBO INDUSTRIES, INC.
Applicants: MUSHA TOSHIMITSU, NISSHIN SPINNING, MUSHA, TOSHIMITSU, NISSHINBO INDUSTRIES, INC.
Application year: 1995
Main classification: D01H5
IPC codes: D02G3, D01H5, D01H1