Elastic yarn production device and production method

Abstract

The invention discloses an elastic yarn production device and method, a drafting system comprising a front row of drafting roller pairs, a middle row of drafting roller pairs and a rear row of drafting roller pairs is adopted, a uniform twisting roller pair is additionally arranged on the rear side of the rear drafting roller pair of the drafting system, and a uniform twisting lower roller of the uniform twisting roller pair periodically rotates forwards and stops rotating; in the forward rotation process, the rotating speed of the uniform twisting lower roller is larger than that of the rear lower roller, so that the fed elastic roving is stacked in length between the uniform twisting lower roller and the rear lower roller, and in the rotation stopping process, the elastic roving with the stacked length is straightened and then instantly generates overall elastic tensioning stretching with the two ends held; therefore, re-propagation of twist in the elastic roving along the length of the roving is achieved under elastic tensioning and stretching, then the periodic uniform twisting arrangement effect on the elastic roving before the elastic roving enters a drafting system is achieved, a stable internal friction force field is provided for drafting of the elastic roving, the drafting effect of the elastic roving is improved, and the comprehensive quality of resultant yarn is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of spinning, and in particular to an elastic yarn production device and a production method. Background Art

[0002] With the continuous progress of the times, people's requirements for clothing fabrics are constantly increasing. Currently, the textile and garment industry is in an era of pursuing fashion, diversification, and high quality. Therefore, new requirements are also put forward for the development of textile raw materials, and various new fibers are continuously developed and applied to spinning processing. Drafting is a key link in spinning processing, which involves the drawing process, roving process, and spinning process in the spinning process. During drafting, fibers are gradually drawn out one by one from the surrounding fiber groups. Due to mutual friction, the hooks are gradually eliminated and the curls are gradually straightened. In this way, the lateral connection remaining inside each fiber may be completely eliminated, creating conditions for firmly establishing a regular head-to-tail connection relationship. Therefore, effective control of fibers during the drafting process is an important condition for achieving excellent drafting effects. Achieving changes in the structure of the processed yarn through changes in drafting is an important way to develop multiple varieties in spinning, such as fancy yarns.

[0003] With the application of various new fiber raw materials, corresponding new requirements are also put forward for drafting. Among them, the spinning processing of fibers with a certain elasticity is particularly prominent. During the drafting process, the control force generated on the fibers comes from friction, including the external friction generated on the fibers after the drafting elements come into contact with the fibers, and the internal friction formed by the entanglement of the fibers with each other. Among them, the internal friction is mainly determined by factors such as the twist of the fed roving and the properties of the fibers in the roving, and the external friction mainly depends on the drafting elements. For fibers with relatively large elasticity, their state in the roving is relatively complex, which makes the internal friction of the roving relatively complex accordingly. Moreover, during the drafting speed change process of the fibers, they will be affected by their own elasticity, which in turn makes the speed change control of the fibers become complex. Therefore, for the production of elastic yarns, how to achieve the stability of the internal friction field, and then cooperate with the corresponding external friction field to effectively control the movement of the fibers during the drafting process, and then improve the quality of the spun yarn, is the key point in spinning processing. Summary of the Invention

[0004] The purpose of the present invention is to provide an elastic yarn production device and a production method. By installing a uniform twist roller pair behind the rear drafting roller pair of the drafting system, uniform twist finishing of the fed elastic roving in elastic tension is realized, providing a stable internal friction field for the drafting of the elastic roving, improving the drafting effect of the elastic roving, and enhancing the comprehensive quality of the spun yarn.

[0005] In a first aspect, the present invention provides an elastic yarn production device, including a drafting system. The drafting system includes a rear pressing and holding continuous conveying jaw, a middle pressing and holding continuous conveying jaw, and a front pressing and holding continuous conveying jaw. A uniform twisting and finishing area is provided at the rear of the drafting system. The uniform twisting and finishing area includes a pressing and holding periodic uniform twisting jaw and a pressing and holding continuous uniform twisting jaw. The pressing and holding continuous uniform twisting jaw and the rear pressing and holding continuous conveying jaw are synchronously driven by the same power source to rotate counterclockwise at a constant speed. The pressing and holding periodic uniform twisting jaw is driven by a separate servo motor to rotate counterclockwise periodically and stop rotating.

[0006] For an elastic yarn production device as described above, preferably, the linear speed of the counterclockwise rotation of the pressing and holding periodic uniform twisting jaw is greater than the linear speed of the counterclockwise rotation of the pressing and holding continuous uniform twisting jaw.

[0007] For an elastic yarn production device as described above, preferably, the linear speed of the rotation of the rear pressing and holding continuous conveying jaw is less than the linear speed of the rotation of the middle pressing and holding continuous conveying jaw.

[0008] For an elastic yarn production device as described above, preferably, the linear speed of the rotation of the middle pressing and holding continuous conveying jaw is less than the linear speed of the rotation of the front pressing and holding continuous conveying jaw.

[0009] For an elastic yarn production device as described above, preferably, within one cycle, the time for the counterclockwise rotation of the pressing and holding periodic uniform twisting jaw is where L is the distance between the pressing and holding periodic uniform twisting jaw and the pressing and holding continuous uniform twisting jaw, and v1 is the linear speed of the counterclockwise rotation of the pressing and holding periodic uniform twisting jaw.

[0010] For an elastic yarn production device as described above, preferably, within one cycle, the time for the pressing and holding periodic uniform twisting jaw to stop rotating is where L is the distance between the pressing and holding periodic uniform twisting jaw and the pressing and holding continuous uniform twisting jaw, v1 is the linear speed of the counterclockwise rotation of the pressing and holding periodic uniform twisting jaw, and v2 is the linear speed of the counterclockwise rotation of the pressing and holding continuous uniform twisting jaw.

[0011] In a second aspect, the present invention provides a method for producing elastic yarn. Using the aforementioned elastic yarn production device, elastic roving processed from elastic staple fibers with an elongation rate of 15% or more is used as the raw material. The elastic roving unwound from the roving bobbin sequentially passes through the pressing and holding periodic twisting nip, the pressing and holding continuous twisting nip, the rear pressing and holding continuous conveying nip, the middle pressing and holding continuous conveying nip, and the front pressing and holding continuous conveying nip, thereby completing the twisting and drafting functions in the drafting system. During this process, the elastic roving first undergoes a periodic twist uniformity finishing effect along the length direction in the twist uniformity finishing area between the pressing and holding periodic twisting nip and the pressing and holding continuous twisting nip, and then enters the drafting system to complete the elongation stretching effect.

[0012] For the method for producing elastic yarn as described above, preferably, the twist uniformity finishing process includes a scaling finishing process and a stretching and twisting process.

[0013] For the method for producing elastic yarn as described above, preferably, during the scaling finishing process, the pressing and holding periodic twisting nip rotates counterclockwise at a linear velocity of v1, causing the elastic roving to be continuously conveyed forward into the twist uniformity finishing area under the holding drive of the pressing and holding periodic twisting nip. And since v1 is greater than v2 at this time, the conveying speed of the elastic roving into the twist uniformity finishing area by the pressing and holding periodic twisting nip is greater than the output speed of the elastic roving from the twist uniformity finishing area by the pressing and holding continuous twisting nip, so that the elastic roving accumulates in length in the twist uniformity finishing area, and then a completely tension-free state of the elastic roving under the holding at both ends in the twist uniformity finishing area is achieved. During the length accumulation process, the additional interference tension generated when the elastic roving is unwound from the roving bobbin completely disappears, and the elastic roving returns to its initial state when it is wound on the roving bobbin. At the same time, when the elastic roving changes from a completely relaxed state to a state with a certain length accumulation, some of the short fibers in the elastic roving curl due to their own elastic stretchability, and further entanglement with each other occurs during the curling process, so that the twist in the elastic roving increases, and then the internal friction field generated by the interaction force between the short fibers in the elastic roving increases. With the continuous counterclockwise rotation of the pressing and holding periodic twisting nip, the length accumulation of the elastic roving in the twist uniformity finishing area continuously increases.

[0014] An elastic yarn production method as described above, wherein, preferably, during the stretching and uniform twisting process, the uniform twisting jaws are stopped from rotating according to the pressing and holding cycle. In the uniform twisting finishing area, the head end of the elastic roving is still held and driven by the continuous uniform twisting jaws of the pressing and holding to continuously output forward from the uniform twisting finishing area, while the tail end of the elastic roving is kept stationary and pressed, so that the elastic roving is continuously output in the uniform twisting finishing area. During the output process, first, the elastic roving gradually changes from a state of having a certain length of accumulation to a tensioned state until the elastic roving is completely straightened. Then, the uniform twisting jaws of the pressing and holding cycle immediately resume counterclockwise rotation at a linear velocity of v1. During the straightening process, due to the inertia of the rear pressing and holding cycle uniform twisting jaws, the elastic roving will instantaneously generate an overall stretch under the two-end holding. Since the elastic roving itself has a certain elasticity, an elastic stretch wave along the length direction is generated during the instantaneous stretching process of the elastic roving. At this time, due to the elastic roving itself having a certain twist and elasticity, the elastic roving realizes an overall stretch instantaneously, that is, there is no mutual sliding between the short fibers in the elastic roving during the stretching process. At the same time, due to the uneven distribution of the twist along the length direction of the elastic roving, different elastic expansions and contractions are generated along the length direction, and then the corresponding elastic stretch waves are different, so that the generated elastic stretch waves propagate in the uniform twisting finishing area along the length direction of the elastic roving. During the propagation process of the elastic stretch wave, it drives the twist in the elastic roving to re-propagate along the length direction of the elastic roving, so as to realize the enhancement of the twist in the weak twist area and the weakening of the twist in the strong twist area while keeping the overall twist in the elastic roving unchanged, and realize the uniform finishing process of the twist along the length direction of the elastic roving in the uniform twisting finishing area.

[0015] Compared with the prior art, the present invention adopts a drafting system including front, middle, and rear rows of drafting roller pairs, and a uniform twisting roller pair is installed behind the rear drafting roller pair of the drafting system. The lower uniform twisting roller of the uniform twisting roller pair periodically rotates forward and stops rotating. During the forward rotation process, the rotational speed of the lower uniform twisting roller is greater than that of the rear lower roller, so that the fed elastic roving forms a length accumulation between the two. During the stop rotation process, the elastic roving with length accumulation is instantaneously subjected to an overall elastic tension stretch under the two-end holding after being straightened, so as to realize the re-propagation of the twist in the elastic roving along the length of the roving under the elastic tension stretch, and then realize the periodic uniform twisting and finishing effect on the elastic roving before entering the drafting system, provide a stable internal friction force field for the drafting of the elastic roving, thereby improving the drafting effect of the elastic roving and enhancing the comprehensive quality of the spun yarn. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an elastic yarn production device provided by an embodiment of the present invention.

[0017] Description of reference numerals:

[0018] 1-elastic roving, 2-even twist bottom roller, 3-even twist upper rubber roller, 4-rear drafting bottom roller, 5-rear drafting upper rubber roller, 6-rear even twist upper rubber roller, 7-middle drafting bottom roller, 8-middle drafting upper rubber roller, 9-front drafting bottom roller, 10-front drafting upper rubber roller, 11-even twist roller shaft, 12-even twist roller sleeve, 13-even twist rubber roller shaft, 14-even twist rubber roller sleeve, 15-drafting roller shaft, 16-drafting roller sleeve, 17-drafting rubber roller shaft, 18-drafting rubber roller sleeve, 19-first servo motor, 20-second servo motor, 21-third servo motor, 22-fourth servo motor, 23-programmable logic controller, 24-yarn guide hook, 25-wire traveler, 26-steel ring, 27-spinning tube. DETAILED DESCRIPTION

[0019] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0020] First, refer to Figure 1 As shown, the present invention provides an elastic yarn production device, including a drafting system, which includes three rows of drafting rollers: a rear drafting roller pair, a middle drafting roller pair, and a front drafting roller pair. The rear drafting roller pair includes a rear drafting lower roller 4 and a rear drafting upper rubber roller group, the middle drafting roller pair includes a middle drafting lower roller 7 and a middle drafting upper rubber roller 8, and the front drafting roller pair includes a front drafting lower roller 9 and a front drafting upper rubber roller 10. The rear drafting lower roller 4, the middle drafting lower roller 7, and the front drafting lower roller 9 include a drafting roller shaft 15. The drafting roller shaft 15 is made of steel and has a solid cylindrical structure.

[0021] The drafting roller shafts 15 of the rear drafting bottom roller 4 of 8-12 spindles on the front or rear car table of the spinning frame are integratedly connected, the drafting roller shafts 15 of the middle drafting bottom roller 7 are integratedly connected, and the drafting roller shafts 15 of the front drafting bottom roller 9 are integratedly connected, and the adjacent drafting roller shafts 15 are connected through a roller seat transmission.

[0022] A drafting roller sleeve 16 is sleeved on the drafting roller shaft 15 of the rear drafting bottom roller 4, the middle drafting bottom roller 7 and the front drafting bottom roller 9 at each spindle position. The drafting roller sleeve 16 of the middle drafting bottom roller 7 and the front drafting bottom roller 9 is made of steel, and the drafting roller sleeve 16 of the rear drafting bottom roller 4 is made of rubber. The diameter of the drafting roller sleeve 16 of the rear drafting bottom roller 4 is larger than the diameter of the drafting roller sleeve 16 of the middle drafting bottom roller 7 and the front drafting bottom roller 9. The drafting roller sleeve 16 is a cylindrical hollow structure with open ends.

[0023] The drafting roller sleeve 16 is sleeved on the drafting roller shaft 15. The drafting roller sleeves 16 of the middle drafting lower roller 7 and the front drafting lower roller 9 are integrally and fixedly connected to the drafting roller shaft 15, and the drafting roller sleeve 16 of the rear drafting lower roller 4 is fixedly connected to the drafting roller shaft 15. The rear drafting upper roller group includes a rear even-twisting upper roller 6 and a rear drafting upper roller 5. The rear even-twisting upper roller 6 is located at the rear side of the rear drafting upper roller 5. The rear even-twisting upper roller 6, the rear drafting upper roller 5, the middle drafting upper roller 8, and the front drafting upper roller 10 have the same structure. The rear even-twisting upper roller 6, the rear drafting upper roller 5, the middle drafting upper roller 8, and the front drafting upper roller 10 include a drafting roller shaft 17, and the drafting roller shaft 17 is made of steel material.

[0024] [[ID=③]]One spindle position on the front car table or the rear car table of the spinning frame and an adjacent spindle position on the left or right side form a spindle position group. The drafting roller shafts 17 of the rear even-twisting upper rollers 6 of the two spindle positions in each spindle position group are integrally connected, the drafting roller shafts 17 of the rear drafting upper rollers 5 are integrally connected, the drafting roller shafts 17 of the middle drafting upper rollers 8 are integrally connected, and the drafting roller shafts 17 of the front drafting upper rollers 10 are integrally connected. A drafting roller sleeve 18 is sleeved on the drafting roller shaft 17 of each spindle position. The drafting roller sleeve 18 is made of rubber material. The drafting roller sleeve 18 and the drafting roller shaft 17 are connected by a first connecting bearing, so that the drafting roller sleeve 18 can rotate freely around the drafting roller shaft 17. The diameters of the drafting roller sleeves 18 of the rear even-twisting upper roller 6 and the rear drafting upper roller 5 are the same and smaller than the diameters of the drafting roller sleeves 18 of the middle drafting upper roller 8 and the front drafting upper roller 10.

[0025] [[ID=⑥]]A certain distance is maintained between the drafting roller sleeves 18 of the rear even-twisting upper rollers 6 of the two spindle positions in a spindle position group, and the drafting roller shaft 17 between the drafting roller sleeves 18 of the rear even-twisting upper rollers 6 of the two spindle positions in a spindle position group is embedded in the first rear embedding claw of the pressing component, so as to realize the installation of the rear even-twisting upper roller 6 on the pressing component.

[0026] [[ID=⑨]]A certain distance is maintained between the drafting roller sleeves 18 of the rear drafting upper rollers 5 of the two spindle positions in a spindle position group, and the drafting roller shaft 17 between the drafting roller sleeves 18 of the rear drafting upper rollers 5 of the two spindle positions in a spindle position group is embedded in the second rear embedding claw of the pressing component, so as to realize the installation of the rear drafting upper roller 5 on the pressing component.

[0027] [[ID=⑫]]A certain distance is maintained between the drafting roller sleeves 18 of the middle drafting upper rollers 8 of the two spindle positions in a spindle position group, and the drafting roller shaft 17 between the drafting roller sleeves 18 of the middle drafting upper rollers 8 of the two spindle positions in a spindle position group is embedded in the middle embedding claw of the pressing component, so as to realize the installation of the middle drafting upper roller 8 on the pressing component.

[0028] A certain distance is maintained between the drafting rubber roller sleeves 18 of the front drafting upper rubber rollers 10 at two spindle positions within a spindle position group, and the drafting rubber roller shafts 17 located between the drafting rubber roller sleeves 18 of the front drafting upper rubber rollers 10 at two spindle positions within a spindle position group are embedded in the front embedding claws of the pressurizing assembly, thereby realizing the installation of the front drafting upper rubber rollers 10 on the pressurizing assembly.

[0029] A uniform twisting roller pair is additionally installed at the rear of the rear drafting roller pair. The uniform twisting roller pair includes a uniform twisting lower roller 2 and a uniform twisting upper rubber roller 3. The uniform twisting lower roller 2 includes a uniform twisting roller shaft 11, and the uniform twisting roller shaft 11 is made of steel. The uniform twisting roller shafts 11 of the uniform twisting lower rollers 2 at 8 - 12 spindle positions on the front or rear carriage table of the spinning frame are integrally connected. A uniform twisting roller sleeve 12 is sleeved on the uniform twisting roller shaft 11 of the uniform twisting lower roller 2 at each spindle position, and the uniform twisting roller sleeve 12 is made of rubber.

[0030] The uniform twisting roller sleeve 12 is sleeved on the uniform twisting roller shaft 11, and the uniform twisting roller sleeve 12 is fixedly connected to the uniform twisting roller shaft 11. The uniform twisting upper rubber roller 3 includes a uniform twisting rubber roller shaft 13, and the uniform twisting rubber roller shaft 13 is made of iron or steel. The uniform twisting rubber roller shafts 13 of the uniform twisting upper rubber rollers 3 at two spindle positions within each spindle position group are integrally connected. A uniform twisting rubber roller sleeve 14 is sleeved on the uniform twisting rubber roller shaft 13 of the uniform twisting upper rubber roller 3 at each spindle position, and the uniform twisting rubber roller sleeve 14 is made of rubber.

[0031] The uniform twisting rubber roller sleeve 14 is connected to the uniform twisting rubber roller shaft 13 through a second connecting bearing, so that the uniform twisting rubber roller sleeve 14 can rotate freely around the uniform twisting rubber roller shaft 13. A certain distance is maintained between the uniform twisting rubber roller sleeves 14 of the uniform twisting upper rubber rollers 3 at two spindle positions within a spindle position group, and the uniform twisting rubber roller shafts 13 located between the uniform twisting rubber roller sleeves 14 of the uniform twisting upper rubber rollers 3 at two spindle positions within a spindle position group are embedded in the third rear embedding claws of the pressurizing assembly, thereby realizing the installation of the uniform twisting upper rubber rollers 3 on the pressurizing assembly.

[0032] The uniform twisting roller shaft 11 of the uniform twisting lower roller 2 is driven to rotate by a first servo motor 19. The first servo motor 19 drives the uniform twisting roller shaft 11 of the uniform twisting lower roller 2 to rotate counterclockwise and stop rotating periodically. The drafting roller shaft 15 of the rear drafting lower roller 4 is driven to rotate by a second servo motor 20. The second servo motor 20 drives the drafting roller shaft 15 of the rear drafting lower roller 4 to rotate counterclockwise all the time. The drafting roller shaft 15 of the middle drafting lower roller 7 is driven to rotate by a third servo motor 21. The third servo motor 21 drives the drafting roller shaft 15 of the middle drafting lower roller 7 to rotate counterclockwise all the time. The drafting roller shaft 15 of the front drafting lower roller 9 is driven to rotate by a fourth servo motor 22. The fourth servo motor 22 drives the drafting roller shaft 15 of the front drafting lower roller 9 to rotate counterclockwise all the time. The first servo motor 19, the second servo motor 20, the third servo motor 21, and the fourth servo motor 22 are all connected to a programmable logic controller 23.

[0033] In a second aspect, the present invention provides a method for producing elastic yarn. During use, the pressing component is pressed down, so that the uniform twisting rubber roller sleeve 14 of the uniform twisting upper rubber roller 3 is closely pressed against the uniform twisting roller sleeve 12 of the uniform twisting lower roller 2, and then an active uniform twisting pressing and holding nip is formed between the uniform twisting rubber roller sleeve 14 of the uniform twisting upper rubber roller 3 and the uniform twisting roller sleeve 12 of the uniform twisting lower roller 2. At the same time, the drafting rubber roller sleeve 18 of the rear uniform twisting upper rubber roller 6 is closely pressed against the rear side of the drafting roller sleeve 16 of the rear drafting lower roller 4, and then a passive uniform twisting pressing and holding nip is formed between the drafting rubber roller sleeve 18 of the rear uniform twisting upper rubber roller 6 and the drafting roller sleeve 16 of the rear drafting lower roller 4. The drafting rubber roller sleeve 18 of the rear drafting upper rubber roller 5 is closely pressed against the front side of the drafting roller sleeve 16 of the rear drafting lower roller 4, and then a rear pressing and holding nip is formed between the drafting rubber roller sleeve 18 of the rear drafting upper rubber roller 5 and the drafting roller sleeve 16 of the rear drafting lower roller 4. At the same time, the drafting rubber roller sleeve 18 of the middle drafting upper rubber roller 8 is closely pressed against the drafting roller sleeve 16 of the middle drafting lower roller 7, and then a middle pressing and holding nip is formed between the drafting rubber roller sleeve 18 of the middle drafting upper rubber roller 8 and the drafting roller sleeve 16 of the middle drafting lower roller 7. At the same time, the drafting rubber roller sleeve 18 of the front drafting upper rubber roller 10 is closely pressed against the drafting roller sleeve 16 of the front drafting lower roller 9, and then a front pressing and holding nip is formed between the drafting rubber roller sleeve 18 of the front drafting upper rubber roller 10 and the drafting roller sleeve 16 of the front drafting lower roller 9.

[0034] The first servo motor 19 drives the twisting roller shaft 11 of the twisting lower roller 2 to periodically rotate counterclockwise first and then stop, and then drives the twisting roller sleeve 14 of the twisting upper rubber roller 3 in close pressing contact therewith to periodically rotate clockwise first and then stop, so that the active twisting pressing and holding jaw is transformed into a pressing and holding periodic twisting jaw. The second servo motor 20 drives the drafting roller shaft 15 of the rear drafting lower roller 4 to always rotate counterclockwise, and then drives the drafting roller sleeve 18 of the rear twisting upper rubber roller 6 in close pressing contact therewith to always rotate synchronously clockwise, so that the passive twisting pressing and holding jaw is transformed into a pressing and holding continuous twisting jaw. At the same time, it drives the drafting roller sleeve 18 of the rear drafting upper rubber roller 5 in close pressing contact therewith to always rotate synchronously clockwise, so that the rear pressing and holding jaw is transformed into a rear pressing and holding continuous conveying jaw. And the counterclockwise rotational linear velocity of the twisting roller sleeve 12 is set to be greater than the rotational linear velocity of the drafting roller sleeve 16 of the rear drafting lower roller 4. The third servo motor 21 drives the drafting roller shaft 15 of the middle drafting lower roller 7 to always rotate counterclockwise, and then drives the drafting roller sleeve 18 of the middle drafting upper rubber roller 8 in close pressing contact therewith to always rotate synchronously clockwise, so that the middle pressing and holding jaw is transformed into a middle pressing and holding continuous conveying jaw. And the rotational linear velocity of the drafting roller sleeve 16 of the middle drafting lower roller 7 is set to be greater than the rotational linear velocity of the drafting roller sleeve 16 of the rear drafting lower roller 4. The fourth servo motor 22 drives the drafting roller shaft 15 of the front drafting lower roller 9 to always rotate counterclockwise, and then drives the drafting roller sleeve 18 of the front drafting upper rubber roller 10 in close pressing contact therewith to always rotate synchronously clockwise, so that the front pressing and holding jaw is transformed into a front pressing and holding continuous conveying jaw. And the rotational linear velocity of the drafting roller sleeve 16 of the front drafting lower roller 9 is set to be greater than the rotational linear velocity of the drafting roller sleeve 16 of the middle drafting lower roller 7.

[0035] During spinning, the elastic roving 1 processed from elastic staple fibers with an elongation rate of more than 15% is used as the raw material. The elastic roving 1 unwound from the roving bobbin sequentially passes through the pressing and holding periodic uniform-twist jaws, the pressing and holding continuous uniform-twist jaws, the rear pressing and holding continuous conveying jaws, the middle pressing and holding continuous conveying jaws, and the front pressing and holding continuous conveying jaws, thereby completing the uniform-twist and drafting functions in the drafting system. During this process, the elastic roving 1 first undergoes a periodic twist uniformity finishing effect along the length direction in the uniform-twist finishing area between the pressing and holding periodic uniform-twist jaws and the pressing and holding continuous uniform-twist jaws. The periodic twist uniformity finishing process of the elastic roving 1 in the uniform-twist finishing area includes a scaling finishing process and a stretching and uniform-twist process. In the scaling finishing process, the first servo motor 19 drives the uniform-twist roller shaft 11 of the uniform-twist lower roller 2 to rotate counterclockwise. Let the rotational linear velocity of the uniform-twist roller sleeve 12 be v1 and the rotational linear velocity of the drafting roller sleeve 16 of the rear drafting lower roller 4 be v2. The elastic roving 1 is continuously conveyed forward under the holding drive of the pressing and holding periodic uniform-twist jaws and enters the uniform-twist finishing area. At this time, since v1 is greater than v2, the conveying speed of the elastic roving 1 into the uniform-twist finishing area by the pressing and holding periodic uniform-twist jaws is greater than the output speed of the elastic roving 1 from the uniform-twist finishing area by the pressing and holding continuous uniform-twist jaws. As a result, the elastic roving 1 accumulates in length in the uniform-twist finishing area, and then a completely tension-free state of the elastic roving 1 under the holding at both ends in the uniform-twist finishing area is achieved. During the length accumulation process, the additional interference tension generated when the elastic roving 1 is unwound from the roving bobbin completely disappears, and the elastic roving 1 returns to its initial state when it was wound on the roving bobbin. At the same time, during the process of the elastic roving 1 changing from a completely relaxed state to a state with a certain length accumulation, some of the staple fibers in the elastic roving 1 curl due to their own elastic stretchability, and further entanglement with each other occurs during the curling process, thereby increasing the twist in the elastic roving 1. Subsequently, the internal friction field generated by the interaction force between the staple fibers in the elastic roving 1 increases. As the first servo motor 19 continuously rotates counterclockwise, the length accumulation of the elastic roving 1 in the uniform-twist finishing area continuously increases. When the length accumulation of the elastic roving 1 in the uniform-twist finishing area reaches a certain required level, and let the time for the first servo motor 19 to drive the uniform-twist roller shaft 11 of the uniform-twist lower roller 2 to rotate counterclockwise be t1, the first servo motor 19 immediately stops working, and then enters the stretching and uniform-twist process. At this time, in the uniform-twist finishing area, the head end of the elastic roving 1 is still held and driven by the pressing and holding continuous uniform-twist jaws and continuously outputs from the uniform-twist finishing area, while the tail end of the elastic roving 1 remains stationary under pressure, so that the elastic roving 1 continuously outputs in the uniform-twist finishing area. During the output process, first, the elastic roving 1 gradually changes from a state with a certain length accumulation to a tensioned state until the elastic roving 1 is completely straightened.Then the first servo motor 19 continues to drive the twisting roller shaft 11 of the lower twisting roller 2 to rotate counterclockwise at a linear velocity of v2, and let the time when the first servo motor 19 stops rotating be t2,

[0036] and it satisfies:

[0037] where L is the distance between the pressing and holding period twisting jaws and the pressing and holding continuous twisting jaws.

[0038] During the straightening process, due to the inertia of the lower twisting roller 2, the elastic roving 1 will instantaneously generate an overall stretch under the two-end holding. Since the elastic roving 1 itself has a certain elasticity, an elastic stretch wave along the length direction is generated during the instantaneous stretching process of the elastic roving 1. At this time, due to the elastic roving 1 itself having a certain twist and elasticity, the elastic roving 1 realizes an overall stretch instantaneously, that is, there is no mutual slip between the short fibers in the elastic roving 1 during the stretching process. At the same time, due to the uneven twist distribution along the length direction of the elastic roving 1, the elastic elongation generated along the length direction is different, and then the corresponding elastic stretch waves are different, so that the generated elastic stretch waves propagate along the length direction of the elastic roving 1 in the twisting and finishing area. During the propagation of the elastic stretch wave, the twist in the elastic roving 1 is driven to re-propagate along the length direction of the elastic roving 1. Thus, while keeping the overall twist in the elastic roving 1 unchanged, the twist in the weak twist area is enhanced and the twist in the strong twist area is weakened, so as to realize the uniform finishing process of the twist of the elastic roving 1 along the length direction in the twisting and finishing area, and thus complete the stretching and twisting process; then, it re-enters the scaling and finishing process, and then realizes a cycle of twisting and finishing including the scaling and finishing process and the stretching and twisting process of the fed elastic roving 1 in the twisting and finishing area before entering the drafting system. And the twisting and finishing cycle T = t1 + t2, and the twisting and finishing cycle is set by the programmable logic controller 23.

[0039] The elastic roving 1 after even-twisting finishing is continuously output by pressing and holding the continuous even-twisting jaws and is held by the rear pressing and holding continuous conveying jaws. In the transition zone between the pressing and holding continuous even-twisting jaws and the rear pressing and holding continuous conveying jaws, since the conveying speeds of the two are kept consistent, the elastic roving 1 has no draft in the transition zone, and then the elastic roving 1 after even-twisting finishing is stable with both ends held in the non-draft state. Then, the elastic roving 1 output after even-twisting finishing and stabilization is conveyed into the drafting system through the rear pressing and holding continuous conveying jaws. In the drafting system, the elastic roving 1 is held by the middle pressing and holding continuous conveying jaws, so that a short fiber bundle with reduced linear density is obtained by the drafting action in the rear drafting zone between the rear pressing and holding continuous conveying jaws and the middle pressing and holding continuous conveying jaws. At this time, since the rotational linear speed of the drafting roller sleeve 16 of the middle drafting lower roller 7 is greater than the rotational linear speed of the drafting roller sleeve 16 of the rear drafting lower roller 4, a lengthening stretching action is generated on the elastic roving 1 under the speed difference between the two. In this process, the drafting force applied by the middle pressing and holding continuous conveying jaws to the elastic roving 1 overcomes the internal friction between the elastic fibers in the elastic roving 1 due to the twist, so that the elastic fibers in the elastic roving 1 slide relative to each other, and an elastic fiber bundle with reduced linear density is obtained. Due to the even-twisting finishing effect of the even-twisting finishing zone on the elastic roving 1, the internal friction of the elastic roving 1 is kept stable, and then the action point where the middle pressing and holding continuous conveying jaws overcome the internal friction of the elastic roving 1 is kept stable, and then the point where the elastic fibers in the elastic roving 1 slide relative to each other is kept stable, and the twist in the obtained elastic fiber bundle is kept stable.

[0040] The elastic fiber bundle is then held by the front pressing and holding continuous conveying jaws, so that an elastic fiber sliver with reduced linear density is obtained by the drafting action in the front drafting zone between the middle pressing and holding continuous conveying jaws and the front pressing and holding continuous conveying jaws. At this time, since the rotational linear speed of the drafting roller sleeve 16 of the front drafting lower roller 9 is greater than the rotational linear speed of the drafting roller sleeve 16 of the middle drafting lower roller 7, a lengthening stretching action is generated on the elastic fiber bundle under the speed difference between the two. In this process, the drafting force applied by the front pressing and holding continuous conveying jaws to the elastic fiber bundle overcomes the friction between the short fibers in the elastic fiber bundle, so that the elastic fibers in the elastic fiber bundle slide relative to each other, and an elastic fiber sliver with reduced linear density is obtained. The internal friction of the elastic fiber bundle with uniform twist distribution is kept uniform and stable, and then the action point where the front pressing and holding continuous conveying jaws overcome the internal friction of the elastic fiber bundle is kept stable, and then the point where the elastic fibers in the elastic fiber bundle slide relative to each other is kept stable, so that an elastic fiber sliver with excellent evenness is obtained. The elastic fiber sliver is continuously output from the drafting system by being driven by the front pressing and holding continuous conveying jaws.

[0041] The elastic fiber sliver output by the drafting system is twisted under the action of the twisting twist transmitted by the spinning system of the ring spinning frame to obtain the final elastic yarn, and the elastic yarn is wound around the ring bobbin 27 in a clockwise or counterclockwise direction. During this process, the main motor drives all the spindles to rotate through the spindle belt, and then drives the ring bobbin 27 to rotate. The rotation of the ring bobbin 27 drives the elastic yarn to pass through the yarn guide hook 24 and the traveller 25 in sequence and wind around the ring bobbin 27, so that the traveller 25 rotates around the ring 26. At this time, due to the flexible structure of the elastic yarn and the weight of the traveller 25 itself, the winding speed of the elastic yarn on the ring bobbin 27 is less than the rotation speed of the ring bobbin 27. The speed difference between the two generates the twisting twist, and the generated twisting twist is transmitted from bottom to top. When it is transmitted to the twisting point, the elastic fiber sliver is twisted under the action of the twisting twist to obtain the required elastic yarn.

[0042] The structure, characteristics and function effects of the present invention have been described in detail based on the embodiments shown in the drawings. The above is only the preferred embodiment of the present invention, but the present invention is not limited to the implementation scope shown in the drawings. Any changes made according to the concept of the present invention, or modified into equivalent embodiments with equivalent changes, still within the spirit covered by the specification and the drawings, shall be within the protection scope of the present invention.

Claims

1. An elastic yarn production device, comprising a drafting system, characterized in that: The drafting system includes a rear pressing and holding continuous conveying jaw, a middle pressing and holding continuous conveying jaw, and a front pressing and holding continuous conveying jaw. A uniform twisting and finishing area is arranged at the rear of the drafting system. The uniform twisting and finishing area includes a pressing and holding periodic uniform twisting jaw and a pressing and holding continuous uniform twisting jaw. The pressing and holding continuous uniform twisting jaw and the rear pressing and holding continuous conveying jaw are synchronously driven by the same power source to rotate counterclockwise at a constant speed. The pressing and holding periodic uniform twisting jaw is driven by a separate servo motor to rotate counterclockwise periodically and stop rotating.

2. The elastic yarn production device according to claim 1, characterized in that: The linear speed of the counterclockwise rotation of the pressing and holding periodic uniform twisting jaw is greater than the linear speed of the counterclockwise rotation of the pressing and holding continuous uniform twisting jaw.

3. An elastic yarn production device according to claim 1, characterized in that: The linear speed of the rotation of the rear pressing and holding continuous conveying jaw is less than the linear speed of the rotation of the middle pressing and holding continuous conveying jaw.

4. An elastic yarn production device according to claim 1, characterized in that: The linear speed of the rotation of the middle pressing and holding continuous conveying jaw is less than the linear speed of the rotation of the front pressing and holding continuous conveying jaw.

5. An elastic yarn production device according to claim 1, characterized in that: During one cycle, the time for the pressing and holding cycle uniform twisting jaws to rotate counterclockwise is where L is the distance between the pressing and holding cycle uniform twisting jaws and the pressing and holding continuous uniform twisting jaws, and v1 is the linear velocity of the pressing and holding cycle uniform twisting jaws rotating counterclockwise.

6. The elastic yarn production device according to claim 1, characterized in that: During one cycle, the time when the pressing and holding cycle uniform twisting jaws stop rotating is where L is the distance between the pressing and holding cycle uniform twisting jaws and the pressing and holding continuous uniform twisting jaws, v1 is the linear velocity of the pressing and holding cycle uniform twisting jaws rotating counterclockwise, and v2 is the linear velocity of the pressing and holding continuous uniform twisting jaws rotating counterclockwise.

7. A method for producing elastic yarn, using the elastic yarn production device according to any one of claims 1 to 6, characterized in that: Using an elastic roving made of elastic staple fibers with an elongation rate of more than 15% as the raw material, the elastic roving unwound from the roving bobbin sequentially passes through the pressing and holding periodic uniform twisting jaw, the pressing and holding continuous uniform twisting jaw, the rear pressing and holding continuous conveying jaw, the middle pressing and holding continuous conveying jaw, and the front pressing and holding continuous conveying jaw, thereby completing the uniform twisting and drafting functions in the drafting system. During this process, the elastic roving first undergoes a periodic twist uniformity finishing effect along the length direction in the uniform twisting and finishing area between the pressing and holding periodic uniform twisting jaw and the pressing and holding continuous uniform twisting jaw, and then enters the drafting system to complete the elongation stretching effect.

8. A method for producing elastic yarn according to claim 7, characterized in that: The twist uniformity finishing process includes a scaling finishing process and a stretching and uniform twisting process.

9. A method for producing elastic yarn according to claim 8, characterized in that: During the scaling finishing process, the pressing and holding periodic uniform twisting jaw rotates counterclockwise at a linear speed of v1, causing the elastic roving to be continuously conveyed forward under the holding drive of the pressing and holding periodic uniform twisting jaw and enter the uniform twisting and finishing area. And because at this time v1 is greater than v2, the conveying speed of the elastic roving into the uniform twisting and finishing area by the pressing and holding periodic uniform twisting jaw is greater than the output speed of the elastic roving from the uniform twisting and finishing area by the pressing and holding continuous uniform twisting jaw. As a result, the elastic roving accumulates in length in the uniform twisting and finishing area, and then realizes a completely tension-free state under the holding of both ends of the elastic roving in the uniform twisting and finishing area. During the length accumulation process, the additional interference tension generated when the elastic roving is unwound from the roving bobbin completely disappears, and the elastic roving returns to its initial state when it is wound on the roving bobbin. At the same time, when the elastic roving changes from a completely relaxed state to a state with a certain length accumulation, some of the short fibers in the elastic roving curl due to their own elastic stretchability, and further entanglement with each other occurs during the curling process, thereby increasing the twist in the elastic roving, and then increasing the internal friction field generated by the interaction force between the short fibers in the elastic roving. With the continuous counterclockwise rotation of the pressing and holding periodic uniform twisting jaw, the length accumulation of the elastic roving in the uniform twisting and finishing area continuously increases.

10. A method for producing elastic yarn according to claim 8, characterized in that: During the stretching and uniform twisting process, when the pressing and holding period of the uniform twisting jaws stops rotating, in the uniform twisting finishing area, the head end of the elastic roving is still held and driven forward continuously by the pressing and holding continuous uniform twisting jaws, while the tail end of the elastic roving remains stationary under pressing, so that the elastic roving is continuously output in the uniform twisting finishing area. During the output process, first, the elastic roving changes from a state of having a certain length of accumulation to a gradually tensioned state until the elastic roving is completely straightened. Then, the pressing and holding period of the uniform twisting jaws immediately resumes counterclockwise rotation at a linear velocity of v1. During the straightening process, due to the inertia of the rear pressing and holding period of the uniform twisting jaws, the elastic roving will instantaneously undergo overall stretching under the holding of both ends. Since the elastic roving itself has a certain elasticity, elastic stretching waves along the length direction are generated during the instantaneous stretching process of the elastic roving. At this time, due to the elastic roving itself having a certain twist and elasticity, the elastic roving undergoes overall stretching instantaneously, that is, there is no mutual sliding between the short fibers in the elastic roving during the stretching process. At the same time, due to the uneven distribution of the twist along the length direction of the elastic roving, different elastic expansions and contractions are generated along the length direction, and then the corresponding elastic stretching waves are different, so that the generated elastic stretching waves propagate along the length direction of the elastic roving in the uniform twisting finishing area. During the propagation of the elastic stretching waves, the twist in the elastic roving is driven to re-propagate along the length direction of the elastic roving, so that, while keeping the overall twist in the elastic roving unchanged, the twist in the weak twist area is enhanced and the twist in the strong twist area is weakened, realizing the uniform finishing process of the twist along the length direction of the elastic roving in the uniform twisting finishing area.

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