Spinning device and spinning method

Abstract

 A spinning device, which is capable of preventing yarn, especially a truly twisted-like spun yarn, in produced packages from dyeing unevenly by controlling the tension, torque, and hairiness number of yarn, in piecing yarn,
The spinning device comprises a delivery roller (17) that delivers spun yarn Y formed in a draft device (4) and an air spinning part (5), a host controller (64) and sub controllers (31,32, and 36) that change the drive speed of a winding means (8) to a first drive speed in normal spinning or to a second drive speed in piecing yarn that is lower than the first drive speed, based on the result detected by a slab catcher (18). A sub controller (13) is also provided for changing jet air pressure of a rotating air current from an air spinning nozzle (19) in an air spinning part (5) to be high or low, based on the change in the drive speed.

Description

Field of the Invention

[0001] The present invention relates to a spinning device, which comprises a hollow guide shaft body, an air spinning nozzle that generates a rotating air current around an end part on an upstream side of delivering yarn in the hollow guide shaft body, and an assistant nozzle that generates a rotating air current in a yarn passage of the hollow guide shaft body, and more particularly such as a method of preventing yarn shape from changing in piecing yarn.

Background of the Invention

[0002] A widely known spinning device, which produces a truly twisted-like spun yarn, comprises a hollow guide shaft body, an air spinning nozzle that generates a rotating air current in an end part on the upstream side of the delivering yarn in the hollow guide shaft body, and a nozzle (this nozzle is described as a suction power generation means in the Unexamined Japanese Patent Publication (Tokkai) No. 2001-40532) provided in a yarn passage of the hollow guide shaft body. In the spinning device as described above, the yarn on the spinning side is discharged first after the yarn is started to be spun with two rotating air currents (the beginnings of the spinning is called "yarn discharging spinning" in this specification), and the yarn is pieced with the yarn piecing device such as a knotter or a splicer. In this case, the yarn ends on the spinning and winding sides are clamped in piecing the yarns, and the both yarn ends are connected after stopping the yarn traveling. Then, the yarn is produced and fed continuously while the yarn ends on the spinning side are clamped, so that the yarn is slacked on the spinning side. However, the yarn tension is maintained in piecing the yarns, as a slack tube having an opening for sucking the yarn on a yarn path, which is a means for sucking the yarn slack, sucks the yarn for absorbing the yarn slack.

[0003] In recent years, high-speed spinning machines are really demanded for producing either the truly twisted-like spun yarn or a fascinated spun yarn. However, the yarn slack part becomes longer when the yarn delivering speed is faster, and the yarn tension cannot be maintained by sucking the yarn with the conventional slack tube. It might be good to make the slack tube capacity larger, however it is difficult to realize because of the space for installing it. Consequently, the shape of the yarn that is spun in changing the yarn tension becomes different from the other part of the yarn that is spun when the yarn tension is maintained, and the yarn that has a different shape from the other is not dyed evenly. Moreover, the yarn slack makes a yarn kink or tangled easily. Furthermore, stiff packages cannot be made and a yarn package quality becomes deteriorated as the yarn is wound loosely on the package when the yarn tension is reduced. Additionally, the change of the torque and a hairiness number of the yarn, inherited in the truly twisted-like spun yarn, also causes the dyeing unevenness of yarn, as a result.

[0004] The same applicant has disclosed another spinning device that maintains the yarn tension in the Japanese patent No. 2560474, which comprises an air nozzle (a spinning nozzle) and a belt type false twist device that twists a yarn falsely to the opposite of the twisting direction of the rotating air current from the air nozzle. The spinning principle is different from the one of the spinning device that produces the truly twisted-like spun yarn, and the belt type false twist device propagates the twist to a front roller of the draft device and binds short staple fibers delivered from the draft device. The fascinated spun yarn is produced by twisting the yarn falsely with the belt type false twist device and applying yarn the rotating air current from the air nozzle. The yarn is twisted falsely by the belt and untwisted after passing through the belt, so that the twist does not affect the shape of the produced yarn so much. Additionally, the Japanese patent No. 2560474 also includes the same yarn piecing mechanism and the slack tube as the spinning device for producing the truly twisted-like spun yarn as described above.

[0005] The belt type false twist device is comprised so as to change the drive speed. The yarn tension is maintained by making the yarn delivering speed slower than the one in normal spinning in piecing the yarn and reducing the volume of the sucking slack yarn with the slack tube, so that the belt drive speed of the device is made to be low. If the belt drive speed is kept to be constant when reducing the yarn delivering speed, the yarn twist volume per unit length is increased. Additionally, the yarn is twisted falsely with the belt mechanically by the contacting the yarn directly, so that the yarn might be broken in twisting unless the twist number is adjusted by controlling the belt drive speed based on the yarn delivering speed. Therefore, the belt drive speed is controlled in order to prevent the yarn from breaking in twisting.

[0006] As described above, the twist number can be adjusted for preventing the yarn from breaking by the twist in the art disclosed in the Japanese patent No. 2560474. However, the drive control of the belt cannot adjust the torque and the hairiness number of the yarn based on the yarn delivering speed, as the fascinated spun yarn is produced by twining a fiber around the part of the fiber with no twist and the both fibers are balanced. Moreover, the art disclosed in the patent No. 2560474 is related to the spinning device for producing the fascinated spun yarn, and the kind of yarn that can be produced is limited and the yarn texture is also deteriorated compared with the truly twisted-like spun yarn that is produced by using the hollow guide shaft body and the rotating air current, so that the spinning machine disclosed in the Japanese patent No. 2560474 is limited to certain application.

[0007] The spinning device of the present invention is related to the truly twisted-like spun yarn, in particular, and is provided for preventing the yarn from dyeing unevenly in the produced packages, by adjusting the tension, torque, and hairiness number of the yarn even in piecing the yarns.

Summary of the Invention

[0008] The problem to be solved by the present invention is described above, and next, the means for solving the above problem will be described. According to claim 1, a spinning device comprises a draft device, an air spinning part, a yarn delivering means that delivers a yarn produced in the air spinning part, and a winding means. The air spinning part is equipped with a hollow guide shaft body, an air spinning nozzle that generates a rotating air current around an end part on the upstream side of the delivering yarn in the hollow guide shaft body, and an assistant nozzle that generates the rotating air current in a yarn passage of the hollow guide shaft body. Moreover, a control unit is provided for changing the drive speeds of a draft device, a yarn delivering mean, and a winding means respectively to a first drive speed in normal spinning or a second drive speed that is lower than the first drive speed in piecing yarn.

[0009] According to claim 2, a yarn defect detection part is provided on a yarn path for detecting yarn defects, and the control unit changes the drive speed to the first drive speed or the second drive speed based on the detection result of the yarn defect detection part.

[0010] According to claim 3, an air pressure switching control unit is provided for changing a jet air pressure of the rotating air current from the air spinning nozzle to be high or low, based on the change in the drive speeds of the draft device, the yarn delivering means, and the winding means.

[0011] According to claim 4, a switching means is provided for changing the air pressure from the air spinning nozzle continuously, and the drive of the switching means is controlled by the air pressure switching control unit.

[0012] According to claim 5, the switching means is provided for changing the air pressure from the air spinning nozzle step by step, and the drive of the switching means is controlled by the air pressure switching control unit.

[0013] According to claim 6, a plurality of spinning units equipped with the draft device, the yarn delivering device, and the winding means is provided, and the speeds thereof can be controlled respectively in each spinning unit.

[0014] According to claim 7, the spinning device as described in claim 1 sets the drive speed to the second drive speed in piecing yarn, and the drive speed is set back to the first drive speed again after piecing yarn.

[0015] According to claim 8, the spinning device as described in claim 2 sets the drive speed to the second drive speed when yarn defects are detected, and the drive speed is set back to the first drive speed again after the yarn is pieced.

[0016] According to claim 9, the spinning device as described in claim 3 changes the jet air pressure from the air spinning nozzle to be reduced based on the change in the drive speed that is reduced from the first drive speed to the second drive speed. After that, the spinning device as described in claim 3 changes the jet air pressure from the air spinning nozzle to the air pressure in normal spinning based on the change in the drive speed from the second drive speed to the first drive speed.

Brief Description of the Drawings

[0017] Figure 1 is a design configuration diagram showing each device of a spinning device in a first embodiment of the present invention.

[0018] Figure 2 is a front view of the spinning device, showing an appearance that a lot of spinning units are laid in a line.

[0019] Figure 3 is a side sectional view showing an air spinning part.

[0020] Figure 4 is an enlarged substantial part of Figure 3.

[0021] Figure 5 is a sectional view taken substantially along the lines III - III of Figure 4.

[0022] Figure 6 is a diagram showing a pattern of changing the yarn delivering speed in the respective devices.

[0023] Figure 7 is a design configuration diagram of each device in the spinning device in a second preferred embodiment of the present invention.

[0024] Figure 8 is a block diagram showing a configuration of a first switching mechanism.

[0025] Figure 9 is a diagram showing a pattern of applying a jet air pressure from an air spinning nozzle.

[0026] Figure 10 is a design configuration diagram of each device in the spinning device in a third preferred embodiment of the present invention.

[0027] Figure 11 is a block diagram showing a configuration of a first switching mechanism.

[0028] Figure 12 is a diagram showing a pattern of changing the jet air pressure from the air spinning nozzle.

Detailed Description of the Preferred Embodiments

[0029] A spinning device in a first embodiment of the present invention will be described with reference to Figure 1 and Figure 2.

[0030] The spinning device in the first embodiment includes a lot of spinning units 3 for producing a spun yarn Y, which are laid in a line to the longitudinal direction of a frame 10 of the spinning divice. As illustrated in Figure 2, a lot of the spinning units 3 are disposed in the frame 10 that connects a motor box 1 and a blower box 2. As illustrated in Figure 1, a draft device 4, an air spinning part 5, a nip roller 16 and a delivery roller 17 that are the yarn delivering means, and a winding means 8 of the spun yarn Y are disposed along a yarn path in each spinning unit 3. The draft device 4 draws a sliver S to produce a fiber bundle F, and delivers the fiber bundle F to the air spinning part 5. The air spinning part 5 applies the rotating air current to the fiber bundle F, and produces the truly twisted-like spun yarn Y. Moreover, the nip roller 16 and the delivery roller 17 discharge yarn while producing the spun yarn Y with the air spinning part 5, and the winding means 8 winds the spun yarn Y onto a package P. Hereinafter, a beginning end side of the yarn path, that the sliver S is discharged, is considered to be the upstream side of the yarn path, and the end side of the yarn path having the winding means 8 is made to the downstream side.

[0031] The front side of the frame 10 is open, and the cross section thereof is formed in a horseshoe shape. A yarn piecing vehicle 9 is arranged so as to travel between the respective spinning units 3, 3, ... along rails 14, 15 in an opening part on the front side. The yarn piecing vehicle 9 includes a yarn piecing device 11 such as a knotter or a splicer equipped with a clamp device not shown in the drawings, a suction nozzle 12 that sucks and grasps the spun yarn Y on the spinning side (upstream side of a yarn breaking part), and a suction mouth 13 that sucks and grasps the spun yarn Y on the winding side (downstream side of the yarn breaking part) from the package P. The suction nozzle 12 and the suction mouth 13 are comprised so as to be turned. Moreover, a blower 76 is loaded on the yarn piecing vehicle 9 as a suction source of both suctions. In piecing yarns, the yarn piecing vehicle 9 is moved to the spinning unit 3 where the spun yarn Y is broken, and the suction nozzle 12 sucks the spun yarn Y that is produced from the air spinning part 5 by turning the suction nozzle 12 upward and coming around the downstream side of the air spinning part 5. Moreover, the suction mouth 13 is turned downward to contact on the surface of the package P that is wound by the winding means 8, picks up the yarn end that is once wound, and sucks the spun yarn Y from the package P. The suction nozzle 12 and the suction mouth 13 sucks and grasp the yarn end on the spinning side (upstream side of the yarn breaking part) and the yarn end on the winding side (downstream side of the yarn breaking part) respectively. Both yarn ends are introduced into the yarn piecing device 11 by turning the suction nozzle 12 and the suction mouth 13 respectively, and the yarns are pieced in the state of being clamped by the clamp device.

[0032] In this specification, the terms on yarn piecing are defined as follows: " Piecing yarn" means to connect both yarn ends that are sucked and grasped byboth the suction nozzle 12 and the suction mouth 13, using the yarn piecing device 11. "Yarn piecing operation" means the operation in the spinning device from the time that the yarn piecing vehicle 9 arrives at the spinning unit 3 where the spun yarn Y is broken to the time of starting normal spinning after " piecing yarn". Moreover, "in piecing yarn" means the time of "piecing yarn", in other words, the time of connecting both yarn ends with the yarn piecing device 11 (from a time T2 to a time T9 as described later). Likewise, "in yarn piecing operation" means the time of "yarn piecing operation", in other words, the interval between the time of arriving the yarn piecing device 11 and the time of starting normal spinning (from a time T6 to a time T7 as described above).

[0033] Next, each device included in the respective spinning units 3 will be described along the yarn path.

[0034] Each device as described later is provided in every spinning unit 3. The draft device 4 comprises a back roller 21a and a third roller 21b respectively along the yarn path, and also comprises a second roller 23 on which an apron 22 is wound and a front roller 24. The back roller 21a and the third roller 21b are driven to be rotated by a motor 25, and the second roller 23 is driven to be rotated by a motor 26. Moreover, the front roller 24 that discharges the fiber bundle F from the draft device 4 to the air spinning part 5 is driven to be rotated by a motor 35, and the nip roller 16, the delivery roller 17, and a friction roller 38 of the winding means 8 are also driven to be rotated by the motor 35. Encoders 28, 29, 39 for a feedback control are directly connected to the respective motors 25, 26, 35, and likewise, sub controllers (control units) 31, 32, 36, which are individually connected, increases and reduces the speed. Especially, the front roller 24, the delivery roller 17 and the friction roller 38 are controlled in phase by the speed control of the motor 35.

[0035] The air spinning part 5 will be described with reference to Figure 3 to Figure 5.

[0036] The air spinning part 5, as illustrated in Figure 3, has an air spinning nozzle 19 that applies rotating air current to the fiber bundle F with making the fiber bundle F, which is drawn and fed from the front controller 24, passing through the air spinning part 5. The spun yarn Y is then produced by the rotating air current from the air spinning nozzle 19 and the action of a hollow guide shaft body 20. The spun yarn Y is truly twisted-like spun yarn, which is wound onto the package P in the state of having torque, inherent to truly twisted-like spun yarn.

[0037] The air spinning nozzle 19, as illustrated in Figure 3, includes a needle holder 44 and casings 65, 66, and the hollow guide shaft body 20 having an assistant nozzle 55 is disposed on the downstream side of a needle holder 43.

[0038] The needle holder 43 has a guide hole 41 introducing the fiber bundle F that is drawn in the tip on the upstream side of the needle holder 43 and retains a needle 42 on the yarn path of the fiber bundle F discharged from the guide hole 41. The hollow guide shaft body 20 is supported by the casing 66 in the middle part to a shaft direction, and a tip part 44 on the upstream side and the casing 65 are disposed at a predetermined interval. Moreover, the casing 65 covers the tip of the hollow guide shaft body 20, and a spinning room 57 is formed between the tip of the hollow guide shaft body 20 and a back end (end part on the downstream side) of the needle holder 43.

[0039] A plurality of first rotating nozzle holes 47 that is open to the spinning room 57 is formed in the casing 65. The first rotating nozzle holes 47, provided opposed to the hollow guide shaft body 20, are the holes that are connected into the spinning room 57 from the outside to the diameter direction of the yarn path formed in the air spinning part 5. As illustrated in Figure 4, the rotating air is then produced in the spinning room 57 by jetting air along the inside of the spinning room 57 to a left-hand direction R1, seen from a yarn delivering direction, in case of a Z-twist. Moreover, the first rotating nozzle hole 47 is formed so as to incline to the downstream side of the delivering direction of the fiber bundle F, for making the air flown to the downstream side.

[0040] The hollow guide shaft body 20, disposed such that an opening 48 formed in the tip part 44 is turned to the needle 42, is formed like a cylinder whose upstream side is tapered off, and a spun yarn passage 49 is formed on a shaft center. The spun yarn passage 49 is formed broaden toward the end to the yarn delivering side. To be more precise, the spun yarn passage 49 is formed such that a diameter becomes broadened in multiple stages, and comprises an introduction hole 50 in the tip part 44 side that is open to the needle holder 43 side, a first enlarged diameter hole 51 whose diameter is enlarged to the downstream side of the introduction hole 50 in stages, a second enlarged diameter hole 52 whose diameter is enlarged in a taper shape, connecting to the downstream side of the first enlarged diameter hole 51 smoothly, and a third enlarged diameter hole 53 whose diameter is enlarged to the downstream side of the second enlarged diameter hole 52 in stages. A delivery hole 54 is formed in an end part on the delivering side of the spun yarn Y in the third enlarged diameter hole 53.

[0041] The assistant nozzle 55 is provided for introducing the fiber bundle F that is rotated in the first rotating nozzle 47 into the introduction hole 50 in the middle of the shaft direction of the hollow guide shaft body 20. As illustrated in Figure 4 and Figure 5, the assistant nozzle 55 includes a plurality of the second rotating nozzle holes 56 provided to the direction perpendicular to the spun yarn passage 49 in the middle of the shaft direction of the hollow guide shaft body 20. In case of the Z-twist, the second rotating nozzle hole 56 is formed so as to flow air along the inside of the spun yarn passage 49 to a right handed-direction R2, seen from the yarn delivering direction. In Figure 5, for example, eight holes are formed at a predetermined interval so as to connect to the first enlarged diameter hole 51. In other words, the assistant nozzle 55 is comprised so as to generate the rotating air to the inverse direction of the air from the air spinning nozzle 19. An air passage 37, extending from the vicinity of the delivery hole 54 to the tip side of the upstream side of the hollow guide shaft body 20 and communicating with the respective second rotating nozzle holes 56, is formed in the inside of the hollow guide shaft body 20. The air passage 37 is connected to a compressed air supply passage 58 on the delivery hole 54 side, and is capable of supplying air to the second rotating nozzle hole 56.

[0042] Additionally, it is preferable that the assistant nozzle 55 is as close to a nip point of the fiber bundle F in the front roller 24 as possible. This is because the fiber bundle F discharged from the front roller 24 is drawn into the hollow guide shaft body 20 with stronger suction power in the yarn discharging spinning and it helps to grasp the fiber by propagating twist to the fiber bundle F discharged from the front roller 24 with a rotating air current from the assistant nozzle 55.

[0043] As illustrated in Figure 1, air is supplied from a compressed air source 6 provided in the spinning device to the air spinning part 5 through a first air pressure switching means 27 and a second air pressure switching means 68 provided in every spinning unit 3. The air that is made to be a predetermined jet air pressure by the first air pressure switching means 27 is supplied to the first rotating nozzle 47 in the air spinning nozzle 19, and the air that is made to be a predetermined jet air pressure by the second air pressure switching means 68 is supplied to the second rotating nozzle hole 56 of the assistant nozzle 55.

[0044] Next, the action of piecing yarn in the spinning part 5 will be described.

[0045] The fiber bundle F delivered to the air spinning part 5 is inserted into the guide hole 41 of the needle holder 43, and the compressed air is jet to the fiber bundle F from both the first rotating nozzle 47 and the second rotating nozzle 56 in the air spinning part 5. The first rotating nozzle 47 is formed inclined to the downstream side of the yarn delivering direction of the fiber bundle F, and the compressed air jet from the first rotating nozzle 47 is flown to the delivering direction of the fiber bundle F with rotating. Therefore, the fiber bundle F inserted into the guide hole 41 of the needle holder 43 is sent to the vicinity of the opening 48 of the hollow guide shaft body 20 with making the fiber bundle F in the loose false twist state with the rotating air current.

[0046] Moreover, in piecing yarn, rotating air current is formed after the compressed air is jet from the second rotating nozzle hole 56 of the assistant nozzle 55 and the compressed air is flown along the internal surface in the spun yarn passage 49 formed in the hollow guide shaft member 20. Additionally, in normal spinning other than the yarn discharging spinning (not in starting to spun yarn), compressed air is not jet from the second rotating nozzle hole 56, and compressed air is jet only from the first rotating nozzle hole 47 and the truly twisted-like spun yarn Y is produced.

[0047] As the spun yarn passage 49 is formed broaden toward the delivering side of the spun yarn Y, the compressed air jet into the spun yarn passage 49 through the second rotating nozzle hole 56 is flown to the delivering side, and the pressure in the introduction part 50 becomes negative. Thus, the air flown to the sucking direction (the direction into the hollow guide shaft body 20) generates in the opening 48 formed in the tip of the hollow guide shaft body 20, so that the fiber bundle F can be drawn continuously.

[0048] The fiber bundle F in false-twist state delivered around the opening 48 of the hollow guide shaft body 20 is sucked into the spun yarn passage 49 in the opening 48 by the suction air current from the opening 48. The fiber bundle F then comes to the first enlarged diameter hole 51 and is exposed to the rotating air current flown to the inverse direction of the one from the air spinning nozzle 19. Therefore, the yarn discharging spinning is carried out by delivering the fiber bundle F in loosely false twist state from the hollow guide shaft body 20 with making the fiber in the fascinated spun yarn state, using the conventional yarn spinning art for producing spun yarn Y with the rotating nozzles that are turned to the opposite directions each other.

[0049] Next, the yarn delivering means will be described.

[0050] The delivery roller 17 on the downstream side of the air spinning part 5 is driven to be rotated by the motor 35, and is disposed such that the nip roller 16 can be contacted with the delivery roller 17 so as to be opposed to the delivery roller 17 across the yarn path. The spun yarn Y passing through the yarn path is delivered to the downstream side by being nipped in between the delivery roller 17 and the nip roller 16 driven to be rotated by contacting with the delivery roller 17. In piecing yarn, the yarn end on the spinning side is formed into a fascinated spun yarn U by the yarn discharging spinning as described above, and the fascinated spun yarn U is delivered from the air spinning part 5. The yarn is sucked into the suction nozzle 12, and the spun yarn Y is guided in between the nip roller 16 and the delivery roller 17 by turning the suction nozzle 12. After that, the yarn is arranged to follow the yarn path, and the yarn delivering power to the downstream side is applied to the yarn. When the yarn is nipped in between the nip roller 16 and the delivery roller 17 after being produced into the fascinated spun yarn U and the yarn is delivered stably, a sub controller 34 and the second air pressure switching means 68 stop to supply the compressed air to the second rotating nozzle hole 56. After the yarn discharging spinning is terminated, only the air spinning nozzle 19 jets air. As described above, the delivery roller 17 is driven by the same motor 35 as the one used by the front roller 24 and the friction roller 38.

[0051] A suction pipe called a slack tube 40 is provided for absorbing yarn slack in piecing yarn on the downstream side of the delivery roller 17. The traveling of the yarn end is stopped by the clamp device in the yarn piecing device 11 during the interval from the time of introducing the both yarns on the spinning side and winding side, sucked and grasped by the suction nozzle 12 and the suction mouth 13, into the yarn piecing device to the time of terminating piecing the yarns in yarn piecing operation, however the yarn is slacked as the yarn on the spinning side is spun continuously. Here, the yarn on the spinning side is sucked continuously with the slack tube 40 for keeping tension, and the yarn slack is then absorbed.

[0052] A slab catcher 18 that is a yarn defect detection part is provided on the downstream side of the slack tube 40 as a means for detecting yarn defects and the presence of the traveling yarn. If the spun yarn Y is broken or the yarn is broken naturally when the yarn defects are detected by the slab catcher 18, the spun yarn Y on the winding side (downstream side of the yarn breaking part) is wound onto the package P side, and the sliver S is stopped to deliver on the spinning side (upstream side of the yarn breaking part).

[0053] The winding means 8 comprises the friction roller 38 abutting against a peripheral surface of the package P and a traverse device 7. As described above, the friction roller 38 is driven by the same motor 35 that is also used by the front roller 24 and the delivery roller 17. The traverse device 7 for winding the spun yarn Y on the package P evenly is provided in the vicinity on the upstream side of the friction roller 38. The traverse device 7 is driven by the motor 44, and an encoder 45 for the feedback control is connected directly to the motor 44. Moreover, a sub controller 46 that increases and reduces the speed of the motor 44 is connected to the motor 44.

[0054] A host controller (control unit) 64 for controlling the sub controllers 31, 32, 36, 46 provided in the spinning unit 3, sends timing signals mainly to each controller in order to make the whole operation conduct smoothly. Moreover, the signal from the slab catcher 18 that is the yarn defect detection part is also input to the host controller 64.

[0055] Next, the spinning and yarn piecing operation in the spinning device in the first embodiment will be described with reference to Figure 1 and Figure 6. Figure 6 is a diagram showing a pattern of changing the yarn delivering speed in the respective devices. Here, the yarn delivering speed of the spun yarn Y is determined by a rotation speed of the friction roller 24 (the draft device 4), the delivery roller 17 (the yarn delivering means), and the friction roller 38 (the winding means 8). In the present invention, in piecing yarn, the length of a yarn slack Ya is made to be reduced by controlling the speed of the respective rollers 24, 17, and 38 that determine the yarn delivering speed of the spun yarn Y.

[0056] Again, "piecing yarn" means to connect both yarn ends that is sucked and grasped by the nozzle 12 and the mouth 13, and "yarn piecing operation" means the operation in the spinning device from the time that the yarn piecing vehicle 9 arrives at the spinning unit 3 to the time of starting normal spinning. Moreover, the time that yarn is pieced is "in piecing yarn", and the time of carrying out "yarn piecing operation" is "in yarn piecing operation". In Figure 6, Figure 9 and Figure 12 that are used for explaining the first to third preferred embodiments as described later, "in piecing yarn" means the times from T6 to T7, and "in yarn piecing operation" means the times from T2 to T9.

[0057] A yarn defect signal is input to the host controller 64 based on the result that yarn is not detected as the yarn Y is cut by a cutter not shown in the drawings after the slab catcher 18 detects yarn defects such as a slab, or the fiber bundle F is choked in the air spinning part 5. The time of detecting yarn defects is shown as the code T0 in Figure 6. The other times as described later are also accorded with the ones in Figure 6. The motor 25 of the draft device 4 is then stopped at once as illustrated in Figure 6A after an instruction signal is output from the host controller 64 to the respective sub controllers, and the yarn delivering speed is changed from the one in normal spinning to the one in the yarn delivering speed in piecing yarn (time T1) after giving an instruction of reducing speed to the motor 29 that drives the second roller 23, the motor 35 that drives three rollers including the front roller 24, the delivery roller 17 and the friction roller 38, and the motor 44 that drives the traverse device 7 (time T0). Hereinafter, a first drive speed is taken for the yarn delivering speed in normal spinning, and a second drive speed is taken for the yarn delivering speed in piecing yarn. The second drive speed is lower than the first drive speed. When the motor 25 in the draft device 4 is stopped, the supply of the sliver S is then stopped and the delivery of the spun yarn Y from the air spinning part 5 is also stopped. Moreover, the spun yarn Y on the downstream side than the broken part is wound into the package P.

[0058] When the yarn defect or the non-existence of yarn is detected, the yarn piecing vehicle 9 arrives at the unit 3 that needs to be pieced (time T2). The yarn piecing operation as described above is then started by turning the suction nozzle 12 and the suction mouth 13, after the draft device 4 and the air spinning part 5 are started up as follows: An instruction is sent from the host controller 64 to the sub controller 31, and the instruction for increasing the speed is given to the motor 25 in the time T2 of turning the suction nozzle 12 and the suction mouth 13, based on the programmed speed pattern as illustrated in Figure 6A. The instruction for increasing the speed is shown in a slant part from the time T2 to T3 in the speed pattern of Figure 6A. Additionally, the package P is made to be apart from the friction roller 38 just before the time T2 and is driven inversely to the package P. Therefore, the sliver S is started to supply again, and the compressed air is started to supply to the second rotating nozzle hole 56 with the second air pressure switching means 68 and the yarn discharging spinning is started.

[0059] When the yarn delivering speed in driving the respective motors 25, 26, 35, and 44 is changed to the second drive speed respectively based on the speed instruction, the yarn delivering speed is maintained to the second drive speed (time from T3 to T7). The drive speed of the traverse device 7 is also controlled based on the yarn delivering speed. At the time of changing the speed, the sliver S is drawn continuously by the draft device 4 and delivered to the air spinning part 5, however the acceleration of the rollers 23, 24 are controlled so as to be constant in the draft device 4, and the speed ratio of the respective controllers 21a, 21b, 23, 24 is controlled so as to be the same as the one in normal spinning after the time T3, so that the suitable-sized sliver S that is properly drawn is introduced into the air spinning part 5, the nozzle is not choked, and the failure of passing yarn is reduced.

[0060] Moreover, the suction nozzle 12 sucks and grasps the yarn on the spinning side during the time from T3 to T6, in which the yarn delivering speed is retained to the second drive speed, and the yarn is nipped in between the delivery roller 17 and the nip roller 16 by turning the nozzle to the original position (time T4). The delivering power to the downstream side is applied to the yarn on the spinning side on the yarn path by being nipped by both rollers.

[0061] The fascinated spun yarn U part is not needed in the yarn on the spinning side for winding only the truly twisted-like spun yarn Y onto the package P. The truly twisted-like part on the upstream side in the fascinated spun yarn U part is needed. Therefore, the yarns are pieced such that the part formed in the truly twisted-like spun yarn Y in the yarn on the spinning side is introduced into the yarn piecing device 11 by sucking and grasping with the suction nozzle 12. In other words, in piecing yarn, the suction nozzle 12 applies the delivering power to the downstream side by sucking the part formed in the fascinated spun yarn U in the yarn on the spinning side and nipping the yarn in between the nip roller 16 and the delivery roller 17, and introduces the yarn to the yarn piecing device 11. After that, the suction nozzle 12 sucks the yarn end on the spinning side until at least the part formed in the truly twisted-like state in the spun yarn Y that is delivered accompanied by finishing the yarn discharging spinning is supplied into the yarn piecing device 11.

[0062] When the fascinated spun yarn U part in the yarn on the spinning side is nipped (time T4), the truly twisted-like spun yarn Y is started to produce in the air spinning part 5 (time T5). The yarn ends on the spinning side and the winding side are then respectively cramped during the time between time T6 to time T7, both yarn ends are maintained at a predetermined position, and the yarn piecing operation is started. At time T6, the produced truly twisted-like spun yarn Y is discharged from the air spinning part 5, and then the fascinated spun yarn U part in the spun yarn Y is entered into the suction nozzle 12 completely and is continued to suck. In the yarn piecing operation, the fascinated spun yarn Y part in the yarn on the spinning side is sucked and grasped by the suction nozzle 12. If the yarn is cut after detecting yarn defects, the yarn end part on the winding side including yarn defects is sucked and grasped by the inverse drive of the package P and the suction mouth 13 after releasing the contact with the friction roller 38 and the package P. The suction with the suction mouth 13 is continued from the time at least that the yarn defect part is entered into the suction mouth 13 completely to the time that the normal truly twisted-like spun yarn is supplied to the yarn piecing device 11. After that, the yarns are pieced by introducing the normal truly twisted-like part in both yarns into the yarn piecing device 11. Then, only the truly twisted-like spun yarn is wound after eliminating the yarn end part including the fascinated spun yarn U by the yarn discharging spinning and the yarn end part including the yarn defects.

[0063] The yarn on the spinning side and the yarn end on the winding side are maintained at a predetermined position for a predetermined time in piecing yarn from the time T6 to the time T7, so that the spun yarn that is produced during the time from T6 to T7 is sucked into the slack tube 40 in a U shape, as shown in Figure 1. Then, the yarn delivering speed is controlled for shortening the length of the yarn slack Ya sucked into the slack tube 40. To explain the speed control more precisely, the speed is controlled to be reduced first (time T0 to T1) to be a second drive speed, and the speed is maintained in the second drive speed for a predetermined time (time T1 to T7).

[0064] Time T7 that is a timing of changing the yarn delivering speed into high speed (from the second to first drive speed) can be specified with the host controller 64 in the following way, for example, however the method is not limited to this. Considering the first method, the timer transmits a detection signal to the host controller 64 when the time T7 has come after passing a predetermined time from the time T2 to T3 by using the timer, for specifying the time T7 with the host controller 64. Considering the second method, the yarn piecing device 11 detects the both yarn ends are connected for specifying the time T7 with the host controller 64.

[0065] In piecing yarn completely (time T7), the yarn piecing device 11 releases to clamp the yarn and the yarn is wound again on the package P after the friction roller 38 contacts the package P again, so that the yarn slack in the slack tube 40 is started to be reduced. As the yarn slack is reduced if the yarn piecing device 11 releases to clamp the yarn and the yarn is wound again, the yarn delivering speed is made to be the first drive speed again for restoring in the normal spinning state and the speed is maintained in the first drive speed after the time T9. Moreover, preferably, if the timing of contacting the package P with the friction roller 38 is set to be slight earlier than the time of starting to increase the speed of the front roller 24 and the delivery roller 17, the rotation speed of the package P itself is increased earlier and the yarn slack in the slack tube 40 can be eliminated in a short time. The speed of the package P is increased earlier so as not to delay the timing in increasing the speed of the package P by the inertia caused by the weight of the package P.

[0066] In piecing yarn completely, the spun yarn Y is produced continuously in the first drive speed.

[0067] As described above, the spinning device in the first embodiment includes the host controller 64 and the sub controllers 31, 32, 36, 46, which control the speed of the second roller 23 and the front roller 24 in the draft device 4, the delivery roller 17 that is the yarn delivering means, and the friction roller 38 that is the winding means based on the result of detecting yarn defects by the slab catcher 18. Additionally, the condition of some kind of yarns can be maintained almost stably without affecting the torque and hairiness number of yarn only by making the yarn delivering speed low even if the jet air pressure from the air spinning nozzle 19 is same as the one in the normal spinning as described in the first embodiment. As described above, as the yarn delivering speed is made to be low by each device provided along the yarn path, the length of the yarn slack Ya can be shortened with keeping the yarn tension.

[0068] Therefore, the length of the slack tube 40 for sucking the yarn slack Ya can be shorten. Moreover, the kink in the yarn slack part and the tangled yarn can be prevented from generating.

[0069] In addition, the host controller 64 and the sub controllers 31, 32, 36, 46 reduce yarn delivering speed when yarn defects are detected with the slab catcher 18, and the yarn delivering speed can be low in advance before starting to piece the yarn with the yarn piecing device 11, so that the yarn delivering speed can be surely made to be low in piecing yarn.

[0070] Next, the spinning device in a second embodiment will be described with reference to Figure 6 to Figure 9.

[0071] The same codes are provided to the members common to the first embodiment, and hereinafter the explanation of the common part will be omitted.

[0072] In the second preferred embodiment, in piecing yarn, the speed of the respective rollers 24, 17, 38 that determine the yarn delivering speed of the spun yarn Y is controlled, and the pressure of air jet from the air spinning nozzle 19 in the air spinning part 5 is controlled to be high or low. This is because the air jet volume that is applied per unit length of the yarn (the fiber bundle F) is increased more than usual if the air pressure jet from the air spinning nozzle 19 is fixed with reducing the yarn delivering speed when the spun yarn Y is produced in the yarn kind other than the yarn as described in the first embodiment (no need to be controlled by the nozzle 19). More precisely, as a short staple fiber comprising the fiber bundle F is enwrapped more strongly than in normal spinning, some part of the yarn becomes strongly tightened and the other part of the produced yarn has different torque and hairiness number. Thus, yarn is dyed unevenly in some parts. Therefore, the jet air pressure is controlled in almost same phase based on the control of the yarn delivering speed.

[0073] As illustrated in Figure 7, a spinning unit 103 comprising the spinning device in the second preferred embodiment is equipped with the sub controllers 33, 34 connected individually in the air pressure switching means 27, 68. Moreover, the sub controllers 33, 34 are also controlled by the host controller 64, and the air pressure switching control unit is comprised by these controllers.

[0074] In the second embodiment, in piecing yarn, the pressure of jet air from the air spinning nozzle 19 is controlled. The yarn delivering speed is controlled as described above, and the respective motors 25, 26, 35, 44 is controlled by the sub controllers 31, 32, 36, 46 based on the speed pattern as illustrated in Figures 6A and 6B.

[0075] As illustrated in Figures 6A and 6B, the yarn discharging spinning from the air spinning part 5 is carried out after the time T3. Therefore, the jet air pressure is controlled to be low by the time T3 at the latest when the yarn delivering speed is changed. The pressure of jet air from the air spinning nozzle 19 is reduced to be low in phase with the change of the motors 25, 26, 35, 44 while producing the fascinated spun yarn U from the time of giving the instruction of reducing the speed of the motors 39, 44 (time T0) to the time that the yarn on the spinning side is nipped into the yarn path (time T4). Additionally, it is preferable that the pressure of jet air from the assistant nozzle 55 is set to be lower than the jet air pressure in the first embodiment by the sub controller 34. The fascinated spun yarn U part formed in the tip part of the yarn on the spinning side is prevented from breaking by changing the pressure of jet air from the air spinning nozzle 19 suitably at the time of the yarn discharging spinning, and the success ratio of the yarn discharging spinning is improved.

[0076] As illustrated in Figure 8, the first air pressure switching means 27 comprises a variable switch valve 70 and a drive means 71 in the switch valve 70. The air spinning nozzle 19 provided in the air spinning part 5 and the compressed air source 6 is connected so as to communicate through the air path 72, and the air pressure supplied to the air spinning nozzle 19 can be changed continuously. The switch valve 70 is switched by the drive of the drive means 71, and the drive means 71 is connected to the sub controller 33. After that, the drive means 71 is controlled so as to switch the switch valve 70 with the sub controller 33 based on the programmed pattern of changing pressure as illustrated in Figure 9. The compressed air is jet from the assistant nozzle 55 while the jet air pressure from the air spinning nozzle 19 is same as the one in piecing yarn, so that the pressure of air from the assistant nozzle 55 is not needed to be changed.

[0077] In the second embodiment, in piecing yarn, the pressure of jet air from the air spinning nozzle 19 is changed continuously based on yarn delivering speed, as illustrated in Figure 6 and Figure 9. The jet air pressure is also reduced when reducing the yarn delivering speed, the pressure is kept constant when the yarn delivering speed is constant, and the pressure is increased more when the yarn delivering speed is increased again. Therefore, the torque and hairiness number of the produced truly twisted-like spun yarn Y in the air spinning part 5 can be same as the one in normal spinning in piecing yarn during the time from T6 to T7 and when restoring to the normal spinning. This is because the energy volume of the jet air applied to the yarn per unit length is also maintained almost constant as the jet air pressure is increased and reduced based on the change in the yarn delivering speed.

[0078] Additionally, as the assistant nozzle 55 is not provided for the spinning in yarn piecing operation but rather provided for the spinning of the fascinated spun yarn U, air is not jet from the assistant nozzle 55 in the yarn piecing operation during the time from T6 to T7.

[0079] As described above, the spinning device in the second embodiment includes the sub controller 33, which is added to the configuration in the first embodiment. The sub controller 33 changes the speed of the front roller 24 in the draft device 4, the delivery roller 17 comprising the yarn delivering means, and the friction roller 38 of the winding means, based on the result of detecting yarn defects by the slab catcher 18, and also changes the pressure of jet air from the air spinning nozzle 19. Thus, in piecing yarn, the yarn slack volume Ya can be limited with maintaining the yarn tension, and the energy of the jet air applied to per unit length of the spun yarn Y can be maintained constant even if changing yarn delivering speed, so that the torque and hairiness number of yarn can be almost same as in normal spinning. Therefore, yarn piecing part is prevented from dyeing unevenly.

[0080] Moreover, in the second embodiment, the pressure of jet air from the air spinning nozzle 19 can be changed continuously with the variable switch valve 71, so that the pressure of jet air from the air spinning nozzle 19 can be changed correctly based on the yarn delivering speed. Thus, the energy of the jet air applied to per unit length of the spun yarn Y can be maintained in the same condition as in normal spinning. Therefore, the state of the spun yarn Y in the yarn piecing part and the part produced by the other normal spinning can be almost same.

[0081] Next, the spinning device in a third embodiment will be described with reference to Figure 6 and Figure 10 to Figure 12.

[0082] As illustrated in Figure 11, a step type switch valve 170 is provided in the spinning device in the third embodiment instead of the variable switch valve 70 provided in the spinning device in the second embodiment. Accordingly, a drive means 171 is provided instead of the drive means 71 as illustrated in the second embodiment, and the first air pressure switching means 127 is provided instead of the first air pressure switching means 27 provided in the second embodiment. Moreover, a sub controller 133 is loaded with the spinning device in the third embodiment instead of the sub controller 33 in the second embodiment based on the change in the switching mechanism. For example, a compressed air generation room 172b in which air pressure is changed to be middle level as illustrated in Figure 12 and the air is supplied, a compressed air generation room 172a in which air pressure is changed to the one in normal spinning and the air is supplied, and the path without passing through the compressed air generation room are connected to each switching valve 170 in parallel. Moreover, the compressed air pressure in a compressed air pressure source 6 is changed to be the air pressure in piecing yarn. The air pressure passing through the compressed air generation room 172a is changed to the one in normal spinning, and the air pressure passing through the compressed air generation room 172b is changed to the one between in normal spinning and in piecing yarn. Air is supplied so as to change these air pressures step by step.

[0083] The switch valve 170 is switched properly by the drive of the drive means 171, and the drive means 171 is connected to the sub controller 133. The drive means 171 is then controlled so as to switch the switch valve 170 by the sub controller 133 based on the programmed pattern of changing pressure as illustrated in Figure 12. The sub controller 133 is also controlled by the host controller 64. Additionally, the number of disposing the compressed air generation room is not limited to the number as described above, and more compressed air generation room whose air pressure is respectively different can be added so as to be multiple levels.

[0084] The difference of the spinning devices in the third and second embodiments only exists in the configurations of the first air pressure switching means 27, 127 (switch valves 70, 170) for the air spinning nozzle 19, so that the explanation of the other part is omitted by providing the same codes to the same members as the other configuration is same. As the configuration of the first air pressure switching means is different, the pattern of changing the pressure of jet air from the air spinning nozzle 19 (illustrated in Figure 12) is different from the one in the second embodiment (illustrated in Figure 8), in the third embodiment. On the other hand, regarding the control of the yarn delivering speed, the respective motors 25, 26, 35, 44 is controlled by the sub controllers 31, 32, 36, and 46 based on the speed pattern as illustrated in Figures 6A and 6B same as the first and second embodiments.

[0085] In the third embodiment, as illustrated in Figure 6 and Figure 12, the pressure of jet air from the air spinning nozzle 19 is reduced when reducing the yarn delivering speed, the pressure is constant when the yarn delivering speed is constant, and the pressure is increased when increasing the yarn delivering speed again. The yarn delivering speed is increased step by step based on the yarn delivering speed during the time T8 when the air pressure is changed to the one in the middle. In the graph illustrated in Figure 12, the solid line shows the jet air pressure, and the dashed line shows a compressed air pressure that is switched in the switching valve 170 of the first air pressure switching means 127. As the propagation velocity of the compressed air is same as the sound speed, time lag occurs between the time of switching in the switching valve 170 and the time that the compressed air pressure supplied from the switching valve 170 is propagated to the air spinning nozzle 19. Thus, the compressed air switched in the switching valve 170 is not completely accorded with the jet air pressure in the air spinning nozzle 19, and the jet air pressure is changed slowly. When the yarn delivering speed is increased, the jet air pressure is changed almost step by step.

[0086] As the pressure of jet air is changed step by step in increasing the speed, the shape of the produced spun yarn Y does not change so much compared with the case of not controlling the jet air pressure based on the yarn delivering speed (the case of maintaining the jet air pressure constant). In other words, the change in the energy volume of the jet air applied per unit length of the yarn is limited to be lower compared with the case of not controlling as described above in the air spinning part 5, so that the torque and hairiness number of the produced truly twisted-like spun yarn Y in the air spinning part 5 can be almost same as the yarn condition in the normal spinning.

[0087] Additionally, if the yarns are pieced in a spinning unit of the spinning device in the first to third embodiments, the respective devices, relating to the delivery of the spun yarn Y including the draft device 4, the delivery roller 17 comprising the yarn delivering means, and the winding means 8 is driven by the drive motor for each spinning unit as described above for reducing the yarn delivering speed without affecting the other spinning unit that carries out normal spinning. Therefore, the yarn delivering speed is changed easily in every spinning unit. In the conventional case that a plurality of the spinning units is driven by the drive means such as a common line shaft, it is difficult to control the speed of each individual spinning unit as there are only two choices, drive or halt condition. However, if the communication means that communicates the drive to each spinning unit individually so as to control the speed is disposed, it is not limited to the configuration by using the drive motor of each spinning unit.

[0088] In piecing yarn, the yarn delivering speed may be controlled to be reduced by the motors 26, 35, 44, based on detection of the arrival of the yarn piecing vehicle 9 by an arrival detection means or detection of the timing in clamping the yarn end by the yarn piecing device 11, as well as detection of the yarn defects by a detection means such as the slab catcher 18 that detects yarn defects.

[0089] The air spinning part in the preferred embodiment is not limited to the configuration as described above. For example, the hollow guide shaft body comprises a former external barrel including a tip part and an introductory part, a rear external barrel connected to a compressed air supply path, and an internal barrel including a first enlarged diameter part, a second enlarged diameter part, a third enlarged diameter part, and a second rotating nozzle hole, which are individual parts, and the air passage may be formed by the intervals among the former external barrel, the rear external barrel, and the internal barrel by engaging them. The assistant nozzle comprised by the second rotating nozzle hole as described above is as closer to the point of nipping the fiber bundle with the front roller as possible. The above barrels may be engaged to be removable by using a seal member such as 0-ring for preventing air leakage. The second rotating nozzle hole can be composed so as to be slanted to the downstream side to the plane orthogonal to the first enlarged diameter part. The air current in the yarn passage, formed by the compressed air jet from the assistant nozzle, is not limited to the rotating air current, and a direct air current that comes from the opening of the tip of the hollow guide shaft body to the outlet and is not rotated is also available.

[0090] According to claim 1, the spinning device comprises the draft device, the air spinning part, the yarn delivering means that delivers the yarn spun from the air spinning part, and the winding means. The air spinning part is equipped with the hollow guide shaft body, the air spinning nozzle that generates rotating air current around the end part on the upstream side of delivering yarn in the hollow guide shaft body, and the assistant nozzle that generates the rotating air current in the yarn passage of the hollow guide shaft body. The control unit is provided, which changes the drive speeds of the draft device, the yarn delivering means, and the winding means to the first drive speed in the normal spinning or the second drive speed in piecing yarn that is lower than the first drive speed, so that the yarn tension can be maintained with shortening the yarn slack length compared with the length in conventional piecing after making the yarn delivering speed by the respective devices provided along the yarn path lower in piecing yarn. Thus, high quality package can be produced. Moreover, as the tension applied to the yarn can be prevented from changing, yarn shape is maintained and yarn is prevented from dyeing unevenly. Furthermore, the kink and tangled state in the yarn slack part can be prevented from generating, which is incidental by getting the length of yarn slack longer.

[0091] According to claim 2, the yarn defect detection part that detects the yarn defects is provided on the yarn path and the control unit changes the speed to the first drive speed or the second drive speed based on the result of detecting yarn defects, so that the yarn delivering speed is surely lowered in piecing yarn operation as the yarn delivering speed is controlled to be reduced and the yarn delivering speed can be lower in advance before starting to piece yarn operation with the yarn piecing device.

[0092] According to claim 3, the air pressure switching control unit is provided, which changes the jet air pressure of the rotating air current from the air spinning nozzle to be high or low, based on the changes in the drive speeds of the draft device, the yarn delivering means, and the winding means. Therefore, the yarn slack volume can be reduced with maintaining the yarn tension and the torque and the hairiness number of the yarn can be almost same as the normal spinning as the energy of the jet air applied to per unit length of the spun yarn can be kept constant even if changing the yarn delivering speed, in piecing yarn. Consequently, the yarn piecing part can be prevented from dyeing unevenly.

[0093] According to claim 4, the switching means that changes the air pressure of the air spinning nozzle continuously is provided and the drive of the switching means is controlled by the air pressure switching control unit, so that the jet air pressure from the air spinning nozzle can be changed correctly based on the yarn delivering speed. Thus, the energy of the jet air applied to per unit length of the spun yarn can be maintained in the almost same condition of the one in normal spinning. Therefore, the states of the yarn piecing part of the spun yarn can be almost same as the part produced by the other normal spinning.

[0094] According to claim 5, the switching means that changes the air pressure from the air spinning nozzle step by step is provided and the air pressure switching control unit controls the drive of the switching means, so that the volume of the jet air applied to per unit length of the yarn can be changed to be lower than the case of not controlling as described above and the torque and the hairiness number of the produced truly twisted-like spun yarn Y in the air spinning part 5 can be almost same as the state in the normal spinning. Furthermore, if there is much difference between the normal pressure and the pressure in piecing yarn, the jet air pressure from the air spinning nozzle is changed gradually under a plurality of steps without rapid change compared with the case of changing the air pressure continuously based on the yarn delivering speed.

[0095] According to claim 6, a plurality of the spinning units equipped with the draft device, the yarn delivering device, and the winding means is provided and the speed can be controlled independently in every spinning unit, so that the yarn delivering speed only in the spinning unit that pieces the yarns can be reduced without affecting the other spinning units that carry out the normal spinning if the yarns are pieced in a spinning unit.

[0096] According to claim 7, the drive speed is made to be the second drive speed in piecing yarn and to be the first drive speed again after finishing piecing yarn by the spinning device as described in claim 1, so that the yarn delivering speed in each device provided along the yarn path is made to be low and the yarn tension can be maintained with making the length of the yarn slack shorter than the slack volume in the conventional piecing. Therefore, the high quality package can be produced. Moreover, as the tension applied to the yarn can be prevented from changing, the yarn shape can be maintained and the yarn can be prevented from dyeing unevenly. Furthermore, the kink in the yarn slack part and the tangled yarn, incidental by getting the yarn slack longer, can be prevented from generating.

[0097] According to claim 8, as the drive speed is made to be the second drive speed when detecting yarn defects and to be the first drive speed again after piecing yarn completely by using the spinning device as described in claim 2, the yarn delivering speed is surely lowered in piecing yarn operation as the yarn delivering speed is controlled to be reduced and the yarn delivering speed can be lower in advance before starting to piece yarn operation with the yarn piecing device.

[0098] According to claim 9, the jet air pressure from the air spinning nozzle is reduced to be lower than the normal spinning based on the change in the speed from the first to second drive speed by reducing the drive speed in piecing yarn, and the jet air pressure of the air spinning nozzle is changed to the air pressure in normal spinning based on the change in the speed from the second to first drive speed again, so that the yarn slack volume can be controlled with maintaining the yarn tension, the energy of the jet air applied to per unit length of the spun yarn can be kept constant even if changing the yarn delivering speed, and the torque and the hairiness number of the yarn can be close to the state in normal spinning. Therefore, the yarn piecing part can be prevented from dyeing unevenly.

Claims

1. A spinning device comprising:

a draft device;

an air spinning part;

a yarn delivering means that delivers a yarn produced in the air spinning part; and

a winding means,

   wherein the air spinning part is equipped with a hollow guide shaft body, an air spinning nozzle that generates a rotating air current around an end part on the upstream side of delivering yarn in the hollow guide shaft body, and an assistant nozzle that generates the rotating air current in a yarn passage of the hollow guide shaft body, and a control unit is provided for changing the drive speeds of the draft device, the yarn delivering means, and the winding means to a first drive speed in normal spinning or a second drive speed that is lower than the first drive speed in piecing yarn.

2. A spinning device as in claim 1, wherein a yarn defect detection part is provided on a yarn path for detecting yarn defects and the control unit changes the drive speed to the first drive speed or the second drive speed based on the result detected by the yarn defect detection part.

3. A spinning device as in claim 1 or claim 2, wherein an air pressure switching control unit is provided for changing a jet air pressure of the rotating air current from the air spinning nozzle to be high or low based on the change in the drive speeds of the draft device, the yarn delivering means, and the winding means.

4. A spinning device as in claim 3, wherein a switching means is provided for changing the air pressure from the air spinning nozzle continuously and the drive of the switching means is controlled by the air pressure switching control unit.

5. A spinning device as in claim 3, the switching means is provided for changing the air pressure from the air spinning nozzle step by step and the drive of the switching means is controlled by the air pressure switching control unit.

6. A spinning device as in any one of claim 1 to claim 5, wherein a plurality of spinning units, equipped with the draft device, the yarn delivering means, and the winding means, is provided, and the speeds thereof can be controlled respectively in each spinning unit.

7. A spinning method, wherein the spinning device as in claim 1 sets the drive speed to the second drive speed in piecing yarn, and sets back to the first drive speed again after piecing yarn.

8. A spinning method, wherein the spinning device as in claim 2 sets the drive speed to the second drive speed when yarn defects are detected, and sets back to the first drive speed again after yarn is pieced.

9. A spinning method, wherein the spinning device as in claim 3 changes the jet air pressure from the air spinning nozzle to be lower than the one in normal spinning based on the change of reducing the drive speed from the first drive speed to the second drive speed in piecing yarn, and after that, the jet air pressure from the air spinning nozzle is changed to the air pressure in normal spinning based on the change of the drive speed from the second drive speed to the first drive speed.

Drawing