A method of spinning fancy yarn based on dynamic twist control

Abstract

The application relates to a fancy yarn spinning method based on dynamic twist control, first and second circular belts serving as false twist units are arranged in sequence between the front roller and the guide hook of a spinning frame, the first and second circular belts move transversely in opposite directions, false twist is applied to the sliver through tangential friction, a rotating torque is simultaneously or respectively applied to the first and second circular belts, and the wrap angle theta 1 of the yarn sliver and the first circular belt and the wrap angle theta 2 of the yarn sliver and the second circular belt are dynamically changed during production. The application provides a mechanism for forming yarn tension through dynamic twist, dynamic twist change is formed through dynamic adjustment of the wrap angle under the condition of less broken ends, the dynamic strong twist area and the dynamic weak twist area are unevenly transferred in the micro aspect, are unstable, and the macro aspect shows that morphological differences of thick and thin sections are staggered, and structure-adjustable fancy yarns are formed.

Description

Technical Field

[0001] This invention belongs to the field of spinning and processing technology, and in particular relates to a spinning method for fancy yarns based on dynamic twist control. Background Technology

[0002] Fancy yarns, with their decorative appearance, come in many varieties and are produced using various methods. The existing structure of fancy yarns consists of core yarn, decorative yarn, and binding yarn. However, with the steady expansion and upgrading of the domestic market, focusing on new consumer demands and adapting to the new trend of consumption upgrading, developing high-quality, high-value-added fabrics using new materials and technologies has become a development trend in textile technology. As the market for personalized textiles gradually expands, innovative designs for yarn structures, breaking through the functional and aesthetic limitations of traditional yarns, and meeting diversified market demands, indicate a broad prospect for the iterative upgrading of fancy yarn technology.

[0003] At present, the main production processes of fancy yarn are: (1) Chemical finishing: By adding finishing agents to change the structure of fiber crystallization zone, a unique optical color effect is achieved. Chemical treatment has a good effect, but poor durability and great environmental pollution; (2) Mechanical and physical: By adding control mechanisms, periodically adjusting the roving feed or roller rotation, special structures such as spiral yarn and slub yarn are formed. Mechanical and physical methods have precise detail control and controllable shape, but the mechanism is complex and the equipment modification cost is high.

[0004] Ring spinning technology is a mechanical and physical production process. Due to its rational process flow, it boasts high production efficiency, strong raw material adaptability, and produces high-quality yarn. Since its inception, it has maintained a dominant position in the yarn production field. Traditional ring-spun yarns exhibit a "tight inside, loose outside" structure, resulting in a stiff yarn feel and poor fabric softness. Changing the yarn structure to improve fabric softness avoids the pollution problems associated with chemical finishing while reducing the additional post-processing steps required by physical finishing, thus lowering production costs and achieving true green environmental protection.

[0005] Patent CN117265713B further optimizes the false twist process in ring spinning technology. By adjusting the linear speed ratio of the circular belt and the wrap angle, the dynamic twist of the yarn exiting the front roller nip is increased, producing ultra-low twist yarn with fewer yarn breaks. Simultaneously, because the false twist mechanism acts on the fiber, it alters the traditional yarn structure of ring spinning, resulting in a fluffy, soft-hand feel and a clear fabric texture. The wrap angle formed by the contact between the yarn sliver and the circular belt is θ1; θ2. The size of the wrap angle affects the friction by changing the tangential pressure, thereby adjusting the false twist efficiency. Theoretically, a larger wrap angle results in higher false twist efficiency; however, in actual production, a larger wrap angle makes yarn splicing more difficult, and the wrap angle is adjusted within a certain range before production.

[0006] However, the existing technology still has the following technical problems: the existing ring spinning false twist technology cannot dynamically adjust the wrap angle during the spinning process, resulting in the production of yarns with uniform structure, and it is impossible to actively and controllably manufacture fancy yarns with periodic effects. Summary of the Invention

[0007] The purpose of this invention is to provide a spinning method for fancy yarns based on dynamic twist control, in order to solve the technical problems mentioned in the background art.

[0008] The technical solution adopted by this invention to solve its technical problem is as follows: a spinning method for fancy yarn based on dynamic twist control is provided. A first circular belt and a second circular belt, serving as false twist units, are sequentially arranged between the front roller and the guide hook of a spinning frame. The yarn sliver formed after the roving is drafted is output from the front roller, first tilting downward at an angle Φ to pass under the first circular belt to form spinning section I, and then passing over the second circular belt to form spinning section II. After passing through the guide hook, the yarn is wound. The first and second circular belts move laterally in opposite directions, and false twisting is performed on the sliver through tangential friction. A rotational torque is applied to the first and second circular belts simultaneously or separately. The axis of the rotational torque is parallel to the length direction of the first circular belt and deviates from the first and second circular belts by a certain distance. This is used to dynamically change the encirclement angle θ1 between the yarn sliver and the first circular belt and the encirclement angle θ2 between the yarn sliver and the second circular belt during production.

[0009] Preferably, the linear speed ratio of the first circular belt and the second circular belt is 1.5 to 8.5.

[0010] Preferably, the dynamic variation range of θ1 is 30°~70°, and the dynamic variation range of θ2 is 50°~90°.

[0011] Preferably, the first and second circular belts are driven to rotate cyclically by a driving device.

[0012] Preferably, the driving device is fixed on the same positioning device, and the positioning device is controlled by a control device to rotate around the axis.

[0013] Preferably, the control device includes a servo motor, and the output shaft of the servo motor is connected to the positioning device via a spiral bevel gear set.

[0014] Preferably, the frequency at which the control device drives the positioning device to rotate is 0.1Hz to 50Hz, the angular amplitude at which the control device drives the false twist unit to rotate is ±5° to ±25°, and the control device adjusts the frequency and amplitude of rotation according to the preset fancy yarn length and pitch.

[0015] The beneficial effects are as follows: This invention optimizes the shortcomings of existing false twist devices that cannot dynamically adjust the wrap angle during spinning. By dynamically adjusting the wrap angle to create dynamic twist changes, microscopically this manifests as uneven and unstable fiber transfer between dynamic strong twist and dynamic weak twist zones; macroscopically, it manifests as morphological differences in the formation of thick and thin places. This allows for the spinning of fancy yarns with adjustable structures.

[0016] Through the "dual circular belt dynamic false twist + encircling angle closed-loop control" technology system, the spinning method of this invention that changes the yarn structure is easy to operate, the produced fancy yarn structure is programmable, the performance is adjustable, the production is sustainable, its style characteristics are significant, and the fabric texture is clear. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the yarn feeding mechanism in the prior art.

[0018] Figure 2 for Figure 1 Cross-sectional view of the false twist unit.

[0019] Figure 3 for Figure 2 A schematic diagram showing the spatial positions of the first and second circular bands.

[0020] Figure 4 This is a schematic diagram of a spinning device that employs a spinning method for fancy yarns based on dynamic twist control.

[0021] Figure 5 for Figure 4 Exploded view of the central control device.

[0022] Figure 6 This is a schematic diagram of the dynamic high-twist and low-twist zones in the yarn produced by spinning fancy yarn using a dynamic twist control-based spinning method.

[0023] Figure 7 This is a schematic diagram of the yarn sliver shape produced by using a spinning method based on dynamic twist control for fancy yarns.

[0024] Figure 8 The graph shows the test results of the unevenness curve of yarn produced by the spinning method of fancy yarn based on dynamic twist control.

[0025] Figure 9 This is a real-life photo of the thick section of yarn produced using a spinning method based on dynamic twist control for fancy yarns.

[0026] Figure 10 These are real-life photos showing the details of yarn woven using a spinning method based on dynamic twist control for fancy yarns.

[0027] Figure 11These are real-life photos of yarns with alternating thick and thin sections spun using a fancy yarn spinning method based on dynamic twist control.

[0028] Among them, 1-roving; 2-back roller; 3-roller; 4-front roller; 5-false twist unit; 6-first circular belt; 7-second circular belt; 8-yarn guide hook; 9-fancy yarn; 10-winding bobbin; 11-positioning plate; 12-bolt; 13-roller bearing; 14-driven spiral bevel gear; 15-base; 16-servo motor; 17-drive spiral bevel gear; 18-bearing housing.

[0029] The same markings in each diagram represent the same component. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] This invention is based on the mechanism of false twist altering yarn structure. Specifically, the yarn sliver is twisted and untwisted twice under the action of two false-twisted circular belts (the belts twist the upper sliver upon contact with the yarn and untwise the lower sliver). Due to the repeated untwisting action, the fiber trajectory changes, forming numerous non-coaxial spirals, i.e., localized back twisting. These irregular structural features alter the outer loose and inner tight structure of the ring-spun yarn. The yarn spinning method is simple to operate, significantly improving the yarn's softness and bulkiness, and resulting in clear fabric texture.

[0032] This invention uses a servo control system to drive the false twist mechanism to rotate periodically, dynamically adjusting the wrap angle to intervene in the twisting and untwisting process of the yarn. When the wrap angle increases, the false twist efficiency improves, the inter-fiber holding force is enhanced, forming a dynamic high-twist zone and a dense yarn (details); when the wrap angle decreases, the false twist efficiency decreases, the untwisting effect dominates, fiber migration intensifies, forming a dynamic low-twist zone and a fluffy yarn (thicknesses). This dynamic control mechanism creates alternating dynamic high-twist and dynamic low-twist zones along the yarn axis, forming a controllable periodic dynamic twist gradient. Due to differences in fiber transfer freedom and holding efficiency, the fiber trajectory changes, thus macroscopically generating structured patterns such as slubs, knots, or ripples on the yarn. By precisely controlling the pattern of this periodic change, the desired pattern can be programmatically formed along the yarn axis.

[0033] In the prior art, a first circular belt 6 and a second circular belt 7, serving as a false twist unit 5, are sequentially arranged between the front roller 4 and the guide hook 8 of a spinning frame. The roving 1, after being drafted, forms a yarn sliver that exits from the front roller 4. It first tilts downwards at an angle Φ, passing under the first circular belt 6 to form spinning section I, and then passes over the second circular belt 7 to form spinning section II. After passing through the guide hook 8, it is wound onto the winding bobbin 10 to obtain yarn. The first circular belt 6 and the second circular belt 7 move laterally in opposite directions, performing false twisting on the sliver through tangential friction. Based on this principle, this invention creatively proposes a spinning method for fancy yarn 9 based on dynamic twist control. Based on the disclosure of the aforementioned patent CN 117265713B, a rotational torque is applied simultaneously or separately to the first circular belt 6 and the second circular belt 7. The axis of the rotational torque is parallel to the length direction of the first circular belt 6 and deviates from the first circular belt 6 and the second circular belt 7 by a certain distance. This is used to dynamically change the encirclement angle θ1 between the yarn sliver and the first circular belt 6 and the encirclement angle θ2 between the yarn sliver and the second circular belt 7 during production.

[0034] The linear speed ratio of the first circular belt 6 and the second circular belt 7 is 1.5 to 8.5. The dynamic variation range of θ1 is 30° to 70°, and the dynamic variation range of θ2 is 50° to 90°. The first circular belt 6 and the second circular belt 7 are driven to rotate cyclically by driving devices. The driving devices are fixed on the same positioning device, and the positioning device is controlled to rotate around the axis by a control device.

[0035] In this embodiment, the control device includes a servo motor 16, the output shaft of which is connected to the positioning device via a spiral bevel gear set. The control device drives the positioning device to rotate at a frequency of 0.1Hz to 50Hz, and drives the false twist unit 5 to rotate at an angle of ±5° to ±25°. The control device adjusts the frequency and amplitude of rotation according to the preset length and pitch of the fancy yarn 9.

[0036] Example 1, as Figure 4 As shown, after installing the false twist unit 5 between the front roller 4 and the guide hook 8 of the ring spinning frame, roving 1 is fed in. After being drafted by the back roller 2, roller 3, and front roller 4, it enters the false twist unit 5. The roving 1 first passes through the first circular belt 6 to form the lower spinning section I, then passes over the upper part of the second circular belt 7 to form the spinning section II, passes through the guide hook 8, and then enters the ring spinning twisting stage.

[0037] A cross-sectional view of the false-twisting working unit is shown below. Figure 2As shown, after the yarn is output from the front roller 4, it forms an angle φ with the original path and successively wraps around the convex surface of the first circular belt 6 of the upper running section. It then passes through the gap between the upper and lower running sections and wraps around the convex surface of the second circular belt 7 of the lower running section. The two circular cross-section belts have the same diameter, ensuring that the radii of curvature of the convex surfaces are consistent. The two circular belts are moved laterally by their respective independent drive devices, applying tangential frictional force to the contacted yarn strands. To enhance control over the floating fibers, the two circular belts move in opposite directions; that is, if the yarn is Z-twist, the first circular belt 6 moves horizontally to the left, and the second circular belt 7 moves horizontally to the right.

[0038] like Figure 3 As shown, in the false twist unit 5, the yarn path forms encirclement angles θ1 and θ2 with the first circular belt 6 and the second circular belt 7, respectively. Force analysis shows that the encirclement angle of the yarn affects the magnitude of the frictional force exerted by the false twisting circular belt on the yarn, thus affecting the false twist efficiency. Theoretically, the larger the encirclement angle, the greater the frictional force and the higher the false twist efficiency. However, considering that in actual production, the encirclement angle is affected by spatial position and spinning stability, the encirclement angle θ1 formed by the contact between the yarn sliver and the first circular belt 6 is 45°–60°, and the encirclement angle θ2 formed by the contact between the yarn sliver and the second circular belt 7 is 60°–75°, with θ1 < θ2.

[0039] The control device controls the wrap angle by rotating the false twist unit 5. Therefore, the false twist unit 5 is fixed to the positioning plate 11 of the control device. Figure 4 The structural diagram shown illustrates this. The false twist unit 5 is fixed to the positioning plate 11 by positioning pins. The positioning plate 11 is rotated by the servo motor 16 of the control device, thereby causing the false twist unit 5 to rotate as a whole.

[0040] The main structure of the control device is as follows Figure 5 As shown, the entire assembly is installed within the base 15. The driving spiral bevel gear 17, driven by the servo motor 16, is mounted on the bearing and bearing housing 18, driving the driven spiral bevel gear 14 to rotate, thereby rotating the roller bearing 13. The positioning plate 11 is fixed to the roller bearing 13 by bolts 12. The servo motor 16 drives the driving spiral bevel gear 17, which, through a high-ratio gear set with a self-locking function, ultimately drives the positioning plate 11 and the entire false twist unit 5 fixed thereon to perform periodic, angle-adjustable reciprocating rotational motion (rather than continuous rotation) around the yarn channel axis, thereby adjusting the wrap angle.

[0041] Because the control mechanism rotates periodically within a certain angle range, the false twist encirclement angle is dynamically adjusted, thus affecting the fiber's degree of freedom of movement and holding efficiency. This results in the yarn's dynamic twisting process exhibiting periodic changes between low-twist and high-twist zones, as shown in the image. Figure 6As shown. The dynamic high-twist zone is achieved by a large encirclement angle: the increased contact arc length between the yarn and the false-twist tape, strong friction between fibers inhibits untwisting, increases the holding force between fibers, hinders fiber transfer, and forms a high-density yarn; the low-twist zone is triggered by a small encirclement angle: reduced contact pressure increases the degree of freedom of fiber movement, untwisting becomes dominant, and radial fiber migration intensifies, leading to yarn bulking. This forms as shown... Figure 7 The patterned yarn shown is 9, with alternating thick and thin textures.

[0042] like Figures 8-11 As shown, a fancy yarn with alternating thick and thin strands prepared according to this method is illustrated. The specific parameters of this yarn are 27.7 tex; twist coefficient 340; and the spinning method is Siro spinning. The yarn yielded the following results after evenness testing: Figure 8 The uneven curve shown indicates that the evenness CV value of this yarn reaches 56.13. (As shown...) Figure 9 , 10 The comparison photos showing the yarn's thick and thin sections reveal that the thicker sections have a diameter of approximately 0.88mm, while the thinner sections have a diameter of approximately 0.28mm. Photos illustrating the alternating thick and thin sections are shown below. Figure 11 The yarn produced by this method exhibits significant differences in diameter between its thick and thin sections. Test results show that the yarn has an alternating thick and thin section structure.

Claims

1. A spinning method for fancy yarns based on dynamic twist control, comprising a first circular belt and a second circular belt serving as a false twist unit, sequentially arranged between the front roller and the guide hook of a spinning frame. The roving, after drafting, forms a yarn sliver output from the front roller, first tilting downwards at an angle Φ around the lower part of the first circular belt to form spinning segment I, then around the upper part of the second circular belt to form spinning segment II. After passing through the guide hook, it is wound to obtain yarn. The first and second circular belts move laterally in opposite directions, performing false twisting on the sliver through tangential friction. Its features are, A rotational torque is simultaneously applied to the first and second circular belts. The axis of this rotational torque is parallel to the length direction of the first circular belt and offset from the first and second circular belts by a certain distance. This is used to dynamically change the encirclement angle θ1 between the yarn sliver and the first circular belt, and the encirclement angle θ2 between the yarn sliver and the second circular belt during production. The first and second circular belts are simultaneously driven to rotate in a cycle by a driving device, which is fixed to the same positioning device. The positioning device is controlled by a control device to rotate around the axis. The control device includes a servo motor, and the output shaft of the servo motor is connected to the positioning device via a spiral bevel gear set. The positioning device is a positioning plate. The false twist unit is fixed on the positioning plate of the control device. The positioning plate is driven to rotate by the servo motor of the control device, thereby driving the false twist unit to rotate as a whole.

2. The spinning method for fancy yarns based on dynamic twist control according to claim 1, characterized in that, The linear speed ratio of the first and second circular belts is 1.5 to 8.

5.

3. The spinning method for fancy yarns based on dynamic twist control according to claim 1, characterized in that, The dynamic range of θ1 is 30° to 70°, and the dynamic range of θ2 is 50° to 90°.

4. The spinning method for fancy yarns based on dynamic twist control according to claim 1, characterized in that, The frequency at which the control device drives the positioning device to rotate is 0.1Hz to 50Hz, and the angular amplitude at which the control device drives the false twist unit to rotate is ±5° to ±25°. The control device adjusts the frequency and amplitude of rotation according to the preset fancy yarn length and pitch.

Images