EP4624401A1

EP4624401A1 - Yarn winding apparatus

Info

Publication number: EP4624401A1
Application number: EP25157862.1A
Authority: EP
Inventors: Masashi Kawai; Katsuhiro SETONO; Takehiro Tsutsumi
Original assignee: Toray Industries Inc; TMT Machinery Inc
Current assignee: Toray Industries Inc; TMT Machinery Inc
Priority date: 2024-03-26
Filing date: 2025-02-14
Publication date: 2025-10-01
Also published as: CN120698304A; JP2025149189A

Abstract

The quality of the innermost layer of a yarn in a package is improved. A yarn winding apparatus 13 includes a winding motor 102 and a traverse device 30 configured to traverse a yarn Y. The winding motor 102 and a traverse motor 31 of the traverse device 30 performs bunch winding of the yarn Y on an empty bobbin B. The yarn winding apparatus 13 further includes a tensiometer 28 and a controller 26. After the bunch winding of the yarn Y on the bobbin B starts and before normal control of causing the traverse device 30 to traverse the yarn Y starts, the controller 26 starts preliminary tension control of controlling the winding speed of the yarn Y by the winding motor 102 based on a result of measurement of the tension by the tensiometer 28.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a yarn winding apparatus.
Patent Literature 1 ( Japanese Laid-Open Patent Publication No. 2010-168146 ) discloses a yarn winding apparatus configured to wind a yarn onto a winding bobbin (take up tube) to form a package. To be more specific, the yarn winding apparatus includes a bobbin holder, a bobbin holder motor, a yarn guide, and a drive motor. The bobbin holder supports the take up tube to be rotatable and is rotationally driven by the bobbin holder motor. The yarn guide guides a yarn to the take up tube, while being driven to move in the axial direction of the take up tube by the drive motor. When yarn threading to an empty take up tube and bunch winding are performed, the drive motor moves the yarn guide in the axial direction of the take up tube to the vicinity of an end portion of the take up tube. As a result, the yarn is caught by a slit formed in the vicinity of the end portion of the take up tube, and the yarn is bunch-wound onto the take up tube. Thereafter, the bobbin holder motor rotationally drives the bobbin holder and the drive motor reciprocally moves the yarn guide. As a result, the yarn is wound onto the take up tube while being traversed.

SUMMARY OF THE INVENTION

Typically, when yarn threading to a take up tube is performed, the yarn needs to be highly tensioned to cause the take up tube to reliably capture the yarn. However, if the tension applied to the yarn is too high, the yarn may be pulled excessively and hence the quality of the yarn wound on the take up tube may deteriorate as compared to the desired quality. Therefore, a high first tension needs to be applied to the yarn at the yarn threading to the take up tube, and a second tension lower than the first tension needs to be applied to the yarn at the winding of the yarn onto the take up tube. However, in known cases, the tension of the yarn immediately after the start of the winding is much higher than the second tension. In this regard, for example, weft yarns of a textile produced in a later step are continuously supplied in such a manner that a terminal portion of a yarn in one package is connected to a start portion of a yarn in a package that is used next to the one package. However, a part (innermost layer) of layers of the yarn in the package, which is close to the terminal portion, is a part where the yarn is wound with a tension significantly higher than the second tension as described above and is a part where the quality of the yarn is low. This is the reason why the part of the textile, which includes the innermost layer of the yarn, may become a part where quality defect in terms of dyeability occurs, for example. Therefore, improvement in quality of the innermost layer of the yarn in the package has been required.
An object of the present invention is to improve the quality of the innermost layer of a yarn in a package.
According to a first aspect of the invention, a yarn winding apparatus which is configured to form a package by winding a yarn onto a take up tube includes: a rotational driving unit which is configured to rotationally drive the take up tube; a traverse unit which is configured to traverse the yarn in an axial direction of the take up tube, in a predetermined traverse area where a yarn layer of the yarn wound onto the take up tube is formed; a bunch winding unit which is configured to perform bunch winding of the yarn at a part of the take up tube outside the traverse area in the axial direction, before the yarn layer is formed; a tension measurement unit which is configured to measure tension of the yarn which is running toward the take up tube; and a controller, after the bunch winding starts and before normal control of causing the traverse unit to traverse the yarn starts, the controller starting preliminary tension control of controlling winding speed of the yarn by the rotational driving unit based on a result of measurement of the tension by the tension measurement unit.
As the yarn is traversed and wound onto the take up tube, the yarn layer of the package is formed. Furthermore, it is typically possible to control the tension applied to the yarn by controlling the winding speed of the yarn. With this arrangement, it is possible in the present invention to control the tension applied to the yarn based on a measurement result of the tension, before the start of the formation of the yarn layer. On this account, as compared to a case where such control is not performed, it is possible to arrange the tension applied to the yarn at the start of the formation of the yarn layer to get close to a desired tension. It is therefore possible to improve the quality of the innermost layer of the yarn in the package.
According to a second aspect of the invention, the yarn winding apparatus of the first aspect of the invention is arranged so that, in the preliminary tension control, the controller decreases the winding speed of the yarn to be lower than the winding speed at the start of the preliminary tension control.
Typically, in order to securely thread the yarn to the take up tube, it is necessary to apply a high tension to the yarn. Furthermore, generally speaking, when the winding speed of the yarn is high, the yarn tends to be pulled and the tension applied to the yarn tends to be increased. On the contrary, when the winding speed of the yarn is low, the tension applied to the yarn tends to be low. According to the aspect of the present invention, it is possible to decrease the tension before the start of the formation of the yarn layer. It is therefore possible to reliably improve the quality of the innermost layer of the yarn in the package.
According to a third aspect of the invention, the yarn winding apparatus of the first or second aspect of the invention is arranged such that the controller starts the preliminary tension control when or after the bunch winding is completed.
Typically, the tension of the yarn tends to become unstable during the bunch winding. In the aspect of the present invention, the preliminary tension control is performed when or after the completion of the bunch winding. It is therefore possible to stably perform the preliminary tension control.
According to a fourth aspect of the invention, the yarn winding apparatus of any one of the first to third aspects of the invention is arranged such that, in the preliminary tension control, the controller controls the rotational driving unit so that the tension of the yarn reaches a target tension that is a predetermined target value of the tension of the yarn in the normal control.
According to the aspect of the present invention, it is possible to cause the tension of the yarn to reach the target tension in the normal control, at the start of the formation of the yarn layer. It is therefore possible to improve the quality of the innermost layer of the yarn in the package, in the same manner as the quality of the layers of the yarn, which are on the outer side in the radial direction of the innermost layer in the package.
According to a fifth aspect of the invention, the yarn winding apparatus of any one of the first to fourth aspects of the invention is arranged such that, in the normal control, the controller controls at least one of the traverse unit or the rotational driving unit based on a result of measurement of the tension by the tension measurement unit.
According to the aspect of the present invention, the control can be flexibly done because the number of control targets in the normal control is large as compared to the preliminary tension control. It is therefore possible to further effectively improve the quality of the innermost layer of the yarn in the package.
According to a sixth aspect of the invention, the yarn winding apparatus of any one of the first to fifth aspects of the invention is arranged such that the traverse unit includes a traverse guide which is configured to be able to reciprocate along the axial direction and is configured to guide the yarn to the take up tube, and the traverse guide is configured to be movable to outside of the traverse area in the axial direction.
In the axial direction, the area where bunch winding is performed on the take up tube is typically outside the traverse area. On this account, during the bunch winding, the yarn is typically positioned outside the traverse area. According to the aspect of the present invention, it is possible to allow the traverse unit to function as part of the bunch winding unit. It is therefore possible to reduce the number of components constituting the yarn winding apparatus as compared to a case where the traverse unit and the bunch winding unit are independent from each other.
According to a seventh aspect of the invention, the yarn winding apparatus of any one of the first to sixth aspects of the invention is arranged so that the traverse unit includes a servo motor which is configured to be able to drive and move the traverse guide and to be able to detect information regarding a position in the axial direction of the traverse guide.
According to the aspect of the present invention, it is possible to accurately control the position of the traverse guide that functions as part of the bunch winding unit. It is therefore possible to further accurately estimate the action of the yarn before and after the bunch winding. On this account, the accuracy of, for example, the timing to start the preliminary tension control can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a profile of a spun yarn take-up machine including a yarn winding apparatus of an embodiment.
FIG. 2 is a front view of a spun yarn take-up machine.
FIG. 3 is a schematic plan view of a traverse device and its surroundings.
FIG. 4 is a schematic profile of the traverse device and its surroundings.
FIG. 5 is a block diagram of an electric configuration of the yarn winding apparatus.
FIG. 6(a) and FIG. 6(b) are front views of the yarn winding apparatus in bobbin switching.
FIG. 7(a) and FIG. 7(b) are front views of the yarn winding apparatus in the bobbin switching.
FIG. 8 shows a traverse device and its surroundings in the bobbin switching.
FIG. 9 is a flow chart of control performed by a controller in the bobbin switching.
FIG. 10 shows a graph of the relationship between a tension applied to a yarn and time.
FIG. 11 relates to a modification and shows a graph of the relationship between a tension applied to a yarn and time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe an embodiment of the present invention. For the sake of convenience, directions shown in FIG. 1 and FIG. 2 are referred to as a front-rear direction, a left-right direction, and an up-down direction. The up-down direction (the up-down direction in the plane of FIG. 1) is a vertical direction in which the gravity acts. The left-right direction (the vertical direction in the plane of FIG. 1 and the left-right direction in the plane of FIG. 2) is a predetermined direction orthogonal to the up-down direction. The front-rear direction (the left-right direction in the plane of FIG. 1) is orthogonal to both the up-down direction and the left-right direction. A direction in which each yarn Y runs is referred to as a yarn running direction.

(Spun Yarn Take-Up Machine)

The following will describe a spun yarn take-up machine 1 including a yarn winding apparatus 13 (described later) of the present embodiment, with reference to FIG. 1 and FIG. 2. FIG. 1 is a profile of the spun yarn take-up machine 1. FIG. 2 is a front view of the spun yarn take-up machine 1.
The spun yarn take-up machine 1 is configured to take up yarns Y spun out from a spinning apparatus 2, to wind the yarns Y onto respective bobbins B (take up tubes of the present invention), and to form packages P. The spinning apparatus 2 is, for example, configured to discharge molten polymer which is a material of the yarns Y, for example. While the material of the yarns Y is, for example, a polyester-based material such as PET, the disclosure is not limited to this arrangement. While the yarn Y is, for example, a monofilament yarn made of a single filament, the disclosure is not limited to this arrangement.
As shown in FIG. 1 and FIG. 2, the spun yarn take-up machine 1 includes a first godet roller 11, a second godet roller 12, and a yarn winding apparatus 13.
The first godet roller 11 is a roller having an axis substantially in parallel to the left-right direction. The first godet roller 11 is positioned below the spinning apparatus 2, for example. On the first godet roller 11, yarns Y are wound while being aligned in the left-right direction. The first godet roller 11 is rotationally driven by an unillustrated motor. As a result, the first godet roller 11 feeds the yarns Y to the downstream side in a yarn running direction.
The second godet roller 12 is a roller having an axis substantially in parallel to the left-right direction. The second godet roller 12 is provided downstream of the first godet roller 11 in the yarn running direction. The second godet roller 12 is provided above and rearward of the first godet roller 11. The second godet roller 12 is rotationally driven by an unillustrated motor. As a result, the second godet roller 12 feeds the yarns Y to the downstream side in the yarn running direction.
The yarn winding apparatus 13 is arranged to be able to perform a winding operation of forming the packages P by winding the yarns Y onto the respective bobbins B. The yarn winding apparatus 13 is provided downstream of the second godet roller 12 in the yarn running direction. The yarn winding apparatus 13 is provided below the second godet roller 12.

(Structure of Yarn Winding Apparatus)

The structure of the yarn winding apparatus 13 will be described with reference to FIG. 1 to FIG. 5. FIG. 3 is a schematic plan view of a later-described traverse device 30 and its surroundings. FIG. 4 is a schematic profile of the traverse device 30 and its surroundings. FIG. 5 is a block diagram of an electric configuration of the yarn winding apparatus 13. As shown in FIG. 1 and FIG. 2, the yarn winding apparatus 13 includes a frame 20, fulcrum guides 21, traverse guides 22, a turret 23, two bobbin holders 24, a contact roller 25, and a controller 26.
The frame 20 is a member either to which constituent features of the take-up winder 13 are attached or in which components of the yarn winding apparatus 13 are accommodated. The frame 20 is provided at, for example, a rear end portion of the yarn winding apparatus 13. Each fulcrum guide 21 functions as a fulcrum when a yarn Y is traversed by each traverse guide 22. Each fulcrum guide 21 is arranged to guide a yarn Y to the downstream side in the yarn running direction. As shown in FIG. 1, the fulcrum guides 21 are provided for the respective yarns Y. The fulcrum guides 21 are aligned in the front-rear direction.
The traverse guides 22 are provided for the respective yarns Y. The traverse guides 22 are aligned in the front-rear direction. Each traverse guide 22 is driven and moved by, for example, a traverse motor 31 (see FIG. 3 and FIG. 5), and is configured to reciprocally move at least in the front-rear direction. With this arrangement, the yarns Y threaded to the traverse guides 22 are traversed about the fulcrum guides 21.
To be more specific, the traverse guides 22 are included in, for example, traverse devices 30 (see FIG. 3), respectively. The traverse devices 30 are aligned in the front-rear direction. The traverse devices 30 which are adjacent to each other in the front-rear direction may be arranged to partially overlap each other in the front-rear direction as shown in FIG. 3. Each traverse device 30 includes, for example, the above-described traverse motor 31, a driving pulley 32, two driven pulleys 33, and an endless belt 34.
The traverse motor 31 is, for example, a servo motor with an unillustrated rotary encoder. The rotation angle of the rotational shaft of the traverse motor 31 is detected by the rotary encoder. This makes it possible to calculate the position of the traverse guide 22 in the front-rear direction (axial direction of bobbin B) based on, for example, a predetermined calculation formula. In other words, the traverse motor 31 is able to detect information regarding the position of the traverse guide 22 in the axial direction.
The driving pulley 32 is a pulley on which the endless belt 34 is wound. The driving pulley 32 is rotationally driven in forward and reverse directions by the traverse motor 31.
Being similar to the driving pulley 32, the two driven pulleys 33 are pulleys on which the endless belt 34 is wound. The two driven pulleys 33 are passively rotated by the action of the endless belt 34. The rotational axis direction of each driven pulley 33 is substantially in parallel to the rotational axis direction of the driving pulley 32. As shown in FIG. 3, the two driven pulleys 33 include a driven pulley 33a provided on the front side and a driven pulley 33b provided on the rear side. A line segment (not illustrated) connecting the rotation axis center of the driven pulley 33a with the rotation axis center of the driven pulley 33b may be tilted relative to the front-rear direction. The driven pulley 33b of one traverse device 30 and the driven pulley 33a of another traverse device 30 arranged behind the one traverse device 30 may be positioned to at least partially overlap each other in the front-rear direction, for example.
The endless belt 34 is wound onto the driving pulley 32 and the two driven pulleys 33. The traverse guide 22 is attached to a substantially linear portion of the endless belt 34, which is located between the two driven pulleys 33. As the traverse motor 31 rotationally drives the driving pulley 32, the endless belt 34 is driven and the traverse guide 22 is reciprocated in the front-rear direction (the axial direction of bobbin B).
The traverse guide 22 can be at any position in a predetermined area (movable area) in the front-rear direction in accordance with the rotational angle of the rotational shaft of the traverse motor 31. In other words, the traveling range of the traverse guide 22 can be changed at will within the movable area. For example, when the winding operation is being performed, the traverse guide 22 is reciprocated within a traverse area T (see FIG. 4) to form a yarn layer YL constituting a package P.
The length in the front-rear direction of the traverse area T is changeable, for example, during the winding operation. This allows, for example, the formation of a known taper-wound package P (see FIG. 1).
In addition to the above, the traverse guide 22 can reach the outside of the traverse area T. For example, a slit S in which a yarn Y is threaded is formed over the entire circumference of the bobbin B, at one end portion (front end portion in FIG. 4) in the axial direction of the bobbin B. The shape of the slit S in a longitudinal cross section of the bobbin B is, for example, a groove-like shape into which a wedge is driven (i.e., a long and narrow V-shape). The traverse guide 22 can move to a position substantially identical with that of the slit S in the front-rear direction.
The structure of the traverse device 30 is not limited to the above-described one. For example, instead of the traverse motors 31 provided to correspond to the respective driving pulleys 32, a single traverse motor (not illustrated) that simultaneously drives the driving pulleys 32 may be provided as a driving source.
The turret 23 is, for example, a disc-shaped member having an axis substantially in parallel to the front-rear direction. The turret 23 is rotationally driven by a turret motor 101 (see FIG. 5).
By the turret 23, the two bobbin holders 24 are rotatably supported. When viewed in the front-rear direction, for example, the two bobbin holders 24 are provided to be point symmetric about the rotation axis center of the turret 23 (see FIG. 2). The axial direction of each bobbin holder 24 is substantially in parallel to the front-rear direction (see FIG. 1). Each bobbin holder 24 supports bobbins B which are aligned in the front-rear direction. In the present embodiment, each bobbin holder 24 supports, for example, six bobbins B. It is noted that the number of bobbins B that the bobbin holder 24 can support is not limited to this number. Each of the two bobbin holders 24 is rotationally driven by an individual winding motor 102 (see FIG. 5; equivalent to a rotational driving unit of the present invention). The yarns Y are simultaneously wound onto the bobbins B (see a bobbin B1) attached to one of the bobbin holders 24 (see a bobbin holder 24A). The one bobbin holder 24 is positioned above the other bobbin holder 24. The one bobbin holder 24 may be referred to as an upper bobbin holder 24, for the sake of convenience.
The two bobbin holders 24 include a bobbin holder 24A and a bobbin holder 24B (see FIG. 2). The bobbin holder 24A is rotationally driven by a winding motor 102 (see a winding motor 102A shown in FIG. 5) corresponding to the bobbin holder 24A. The bobbin holder 24B is rotationally driven by a winding motor 102 (see a winding motor 102B shown in FIG. 5) corresponding to the bobbin holder 24B.
The contact roller 25 is provided immediately above the upper bobbin holder 24. The axial direction of the contact roller 25 is substantially in parallel to the front-rear direction. The contact roller 25 is configured to make contact with the surfaces of the packages P supported by the upper bobbin holder 24. With this, the contact roller 25 applies a contact pressure to the surface of each package P to adjust the shape of each package P.
The controller 26 includes, e.g., a CPU, a ROM, and a RAM which are not illustrated. As shown in FIG. 5, the controller 26 is electrically connected to each component of the yarn winding apparatus 13 (see, e.g., the traverse motor 31, the turret motor 101, and the winding motor 102 described above). The controller 26 is configured to be able to control the operation of each component of the yarn winding apparatus 13.
In the yarn winding apparatus 13 structured as described above, when the upper bobbin holder 24 is rotationally driven, the yarns Y traversed by the traverse guides 22 are wound onto the bobbins B, with the result that the packages P are formed. When the formation of the packages P is completed, the turret 23 is rotated so as to switch over the upper and lower positions of the two bobbin holders 24. Because of this, the bobbin holder 24 having been at the lower position is accordingly moved to the upper position. The yarns Y are wound on the respective bobbins B attached to the upper bobbin holder 24, so as to form the packages P. In this regard, the bobbin holder 24 to which the fully-formed packages P are attached is moved to the lower position. Furthermore, the fully-formed packages P are collected by, e.g., an unillustrated package collector. The operation of the yarn winding apparatus 13 when the positions of the two bobbin holders 24 are swapped in the up-down direction is referred to as bobbin switching for the sake of convenience.
The yarn winding apparatus 13 further includes a yarn threading guide 27 (see FIGs. 2 and 4) and a tensiometer 28 (see FIG. 1; a tension measurement unit of the present invention). The yarn threading guide 27 is configured to temporarily hold and move the yarns Y at the time of the bobbin switching. As shown in FIG. 2, the yarn threading guide 27 includes a rotation shaft 41, a supporting member 42, and a yarn holding member 43.
The rotation shaft 41 extends in the front-rear direction (direction perpendicular to the plane of FIG. 2). The rotation shaft 41 supports the support member 42 to be rotatable. The supporting member 42 is, for example, a substantially plate-shaped member extending in the front-rear direction. The supporting member 42 is driven and moved between a standby position (see full lines in FIG. 2) and a yarn holding position (see two-dot chain lines in FIG. 2) by a first drive unit 103 (see FIG. 5). The standby position is a position that does not overlap the turret 23 when viewed in the front-rear direction, for example. The yarn holding position is a position of the supporting member 42, where the yarns Y are held by the yarn holding member 43. (This will be detailed later) . The first drive unit 103 may include, for example, an unillustrated motor as a driving source. Alternatively, the first drive unit 103 may include, for example, an unillustrated air cylinder as a driving source. The first drive unit 103 is electrically connected to the controller 26 (see FIG. 5).
The yarn holding unit 43 is configured to hold the yarns Y to be separated from one another in the front-rear direction (i.e., in the axial direction of the bobbins B). The yarn holding member 43 has, for example, a plurality of holding grooves 43a (see FIG. 4) provided to correspond to the respective yarns Y. Each of the holding grooves 43a is capable of capturing and holding a single yarn Y. FIG. 4 shows only one holding groove 43a in a case where the supporting member 42 is positioned at the yarn holding position. In the vicinity of an entrance through which the yarn Y enters and leaves the holding groove 43a, a protrusion (not illustrated) may be provided to avoid the drop off of the held yarn Y, for example.
The yarn threading guide 27 is driven and moved in the front-rear direction, for example, by the second drive unit 104 (see FIG. 5). (See an arrow extending in the left-right direction on the plane of FIG. 4). The second drive unit 104 may include, for example, an unillustrated air cylinder as a driving source. Alternatively, the second drive unit 104 may, for example, have an unillustrated linear actuator as a driving source. The second drive unit 104 is electrically connected to the controller 26 (see FIG. 5). The yarn holding member 43 is driven and moved between, for example, a yarn capturing position (see two-dot chain lines in FIG. 4) and a yarn threading position (see dotted lines in FIG. 4) by the second drive unit 104. The yarn capturing position is a position of the yarn holding member 43, where the yarns Y are captured by the respective holding grooves 43a. The yarn threading position is a position of the yarn holding member 43, where the yarns Y are threaded into the slits S of empty bobbins B.
The tensiometer 28 is a device configured to measure the tension of one yarn Y among the yarns Y. The tensiometer 28 is a tensiometer which, for example, utilizes a known strain gauge. The tensiometer 28 is configured to be able to measure the tension of a running yarn Y. The tensiometer 28 is positioned immediately upstream in the yarn running direction of one of the fulcrum guides 21, for example (see FIG. 1). The one fulcrum guide 21 may be the frontmost fulcrum guide 21 among the fulcrum guides 21, for example (see FIG. 1).

(Outline of Bobbin Switching)

Now, the steps of the bobbin switching will be outlined with reference to FIG. 6(a) to FIG. 8. FIG. 6(a) to FIG. 7(b) are front views of the yarn winding apparatus 13 at the bobbin switching. FIG. 8 shows the traverse device 30 and its surroundings at the bobbin switching.
Assume that yarns Y are wound onto bobbins B1 and packages P (packages P1) are being formed (see FIG. 6(a)). When the formation of the packages P1 is finished, the controller 26 (see FIG. 5) starts a bobbin switching operation. To begin with, the controller 26 controls the turret motor 101 (see FIG. 5) to rotate the turret 23, so as to move the packages P1 away from the contact roller 25 (see FIG. 6(b)). During this operation, the bobbin holder 24A is rotating and each traverse guide 22 is reciprocating. Furthermore, the controller 26 controls the winding motor 102B (see FIG. 5) to start the rotation of the bobbin holder 24B (and empty bobbins B2). The controller 26 rotates the turret 23 to a position where the yarns Y come into contact with the respective rotating bobbins B2 (see FIG. 6(b)). The controller 26 controls the winding motor 102A so that the circumferential speed of the bobbin B1 on the package P1 side is high as compared to the circumferential speed in the winding operation. In this way, it is possible to increase the tension applied to the yarns Y which are in contact with the bobbins B2. Therefore, it is possible to smoothly thread each yarn Y into the slit S of the bobbin B2 corresponding to that yarn Y, in subsequent yarn threading to the bobbins B2. In addition to the above-described control of the winding motor 102A, the controller 26 controls the winding motor 102B so that the circumferential speed of the bobbin B2 is high as compared to the circumferential speed in the winding operation. This is to prevent the yarn Y from being disadvantageously wound onto the contact roller 25, etc. by suppressing the slackening of the yarn Y immediately after the yarn Y is passed to the bobbin B2.
Subsequently, the controller 26 controls the first drive unit 103 (see FIG. 5) to rotate the yarn threading guide 27 and to move the supporting member 42 from the standby position to the yarn holding position (see FIG. 7(a)). At this stage, the holding grooves 43a are positioned at the yarn capturing position (indicated by two-dot chain lines in FIG. 4). As a result, the yarns Y which are being traversed are captured by the yarn holding member 43 through the entrances of the corresponding holding grooves 43a.
Subsequently, the controller 26 controls the traverse motor 31 to move each traverse guide 22 in the front-rear direction to a position in the vicinity of the slit S of the corresponding bobbin B2 (not illustrated). In this state, the controller 26 controls the second drive unit 104 (see FIG. 5) to move each holding groove 43a in the front-rear direction to a position substantially identical with that of the slit S of the corresponding bobbin B2 (see FIG. 8).
Subsequently, the controller 26 is on standby until the tension of the yarn Y becomes stable, based on a measurement result of the tension of the yarn Y by the tensiometer 28 (see FIG. 1). After determining that the tension of the yarn Y has become stable, the controller 26 controls the traverse motor 31 to move each traverse guide 22 in the front-rear direction to a position substantially identical with that of each slit S (see FIG. 8). As the movement of the traverse guide 22 is stopped at this position, the yarn Y is guided into the slit S of the bobbin B2. As a result, the yarn Y is threaded to the slit S of the rotating bobbin B2 (see FIG. 8). The position of each of the traverse guide 22 and the yarn threading guide 27 at this stage is referred to as the yarn threading position for the convenience of explanation. The yarn Y that is threaded to the slit S is gripped by the bobbin B2 as the yarn Y is inserted into the slit S having the above-described shape, and is pulled in the rotational direction of the bobbin B2. As a result, a high tension is applied to a part of the yarn Y between the bobbin B2 and the package P1, and that part of the yarn Y is cut by the tension. As a result, the package P1 is separated from the yarn Y. The control of moving the traverse guide 22 and the yarn threading guide 27 to their respective yarn threading positions is referred to as yarn threading control for the convenience of explanation.
After the yarn threading control, the controller 26 is on standby for a predetermined time. As a result, after the yarn Y is threaded to the bobbin B2, bunch winding (straight winding) is performed in the vicinity of the slit S of the rotating bobbin B2, and hence a bunch YB is formed (see FIG. 4). A combination of the winding motor 102 (specifically the winding motor 102B), the traverse guide 22, and the traverse motor 31 stopping the movement of the traverse guide 22 corresponds to a bunch winding unit of the present invention.
Subsequently, the controller 26 rotates the yarn threading guide 27 and moves the supporting member 42 from the yarn holding position to the standby position (see FIG. 7(b)). Then the controller 26 moves the traverse guide 22 to the traverse area T. In doing so, tail winding is performed for the bobbin B2 and a tail YT (see FIG. 4) is formed. Subsequently, the controller 26 reciprocates the traverse guide 22 in the traverse area T, and hence the yarn Y is wound onto the bobbin B2. The bobbin switching is completed in this way.
In this regard, in the yarn threading to the bobbin B, the yarn Y needs to be highly tensioned to cause the bobbin B to reliably capture the yarn Y. However, if the tension applied to the yarn Y after the yarn threading to the bobbin B is too high, the yarn Y is pulled excessively. As a result, the quality of the yarn Y wound on the bobbin B may deteriorate as compared to the desired quality. Therefore, a high first tension needs to be applied to the yarn Y at the yarn threading to the bobbin B, and a second tension lower than the first tension needs to be applied to the yarn Y at the winding of the yarn Y onto the bobbin B. However, in known cases, the tension of the yarn Y immediately after the start of the winding is much higher than the second tension. In this regard, for example, weft yarns of a textile produced in a later step are continuously supplied as a terminal portion of a yarn Y in one package P is connected to a start portion of a yarn Y in a package P that is used next to the one package P. However, a part (innermost layer) of layers of the yarn Y in the known package P, which is close to the terminal portion, is a part where the yarn Y is wound with a tension significantly higher than the second tension as described above and is a part where the quality of the yarn Y is low. This is the reason why the part of the textile, which includes the innermost layer of the yarn Y, may become a part where quality defect in terms of dyeability occurs, for example. On this account, in order to improve the quality of the innermost layer of the yarn Y in the package P, the controller 26 performs the below-described control.

(Details of Control in Bobbin Switching)

The details of the control performed by the controller 26 in the bobbin switching will be explained mainly with reference to FIG. 9 and FIG. 10. FIG. 9 is a flow chart of control performed by the controller 26 in the bobbin switching. FIG. 10 shows a graph of the relationship between a tension applied to the yarn Y and time. The horizontal axis of this graph represents time. The vertical axis of the graph represents a measured value of the tension of the yarn Y, which is measured by using the tensiometer 28 (see FIG. 1). Tt is a target value for the tension of the yarn Y (hereinafter, this will be simply referred to as tension), which is set in advance in the controller 26. This target value will be referred to as a target tension Tt. The target tension Tt corresponds to the above-described second tension. Ta is the maximum tension at which the quality of the yarn Y wound on bobbin B is assured to be sufficiently high, for example. Hereinafter, this maximum value will be referred to as a maximum allowable tension Ta. The maximum allowable tension Ta is higher than the target tension Tt.
In an initial state, the winding operation is being performed. That is to say, the yarn Y is wound onto each of the bobbins B (bobbins B1) supported by one of the bobbin holders 24 (assume that this bobbin holder 24 is a bobbin holder 24A), and a package P (package P1) is formed. At this stage, the controller 26 controls the tension of the yarn Y based on a measurement result of the tension measured by the tensiometer 28. More specifically, the controller 26 performs feedback control of at least one of the traverse motor 31 or the winding motor 102, in order to cause, for example, the tension to reach the target tension Tt (in other words, to cause the tension to get as close as possible to the target tension Tt). The tension during the winding operation can be controlled to some extent, mainly by the traversal speed and winding speed. The controller 26 controls the traversal speed and the winding speed (i.e., the circumferential speed of the package P1) so that the tension during the formation of the package P is equal to the target tension Tt, for example. The control method may be, for example, known feedback control such as PID control, or may be another control method. In this way, the control performed by the controller 26 during the winding operation is equivalent to normal control of the present invention.
To begin with, the controller 26 determines a timing at which the formation of the package P1 is completed (step S101 shown in FIG. 9). For example, the formation of the package P1 is completed at a time t0 in the graph in FIG. 10. The time t0 is a time point at which a predetermined time has elapsed from the start of the formation of the package P1, for example. The controller 26 determines that a timing to complete the formation of the package P1 has arrived, when the predetermined time elapses from the start of the formation of package P1.
When determining that a timing to complete the formation of the package P1 has arrived, the controller 26 initiates the bobbin switching operation (step S102). To be more specific, the controller 26 performs control such as separating the packages P1 from the contact roller 25 by rotating the turret 23. At this stage, as described above, the yarns Y are brought into contact with the bobbins B2, respectively (see FIG. 7(b)). Furthermore, at this stage, the circumferential speed of each of the bobbins B1 on the package P1 side is higher than the circumferential speed in the winding operation, as described above. Due to this, as shown in FIG. 10, the tension becomes higher than the maximum allowable tension Ta, for example (see a time after the time t0). As described above, the controller 26 is on standby until the tension becomes stable at a high value. Furthermore, the circumferential speeds of the bobbins B2 are higher than the circumferential speed during the winding operation, as described above. The time at which the tension becomes stable is referred to as a time t1 (see FIG. 10). At the time t1, the tension is stable at Th shown in FIG. 10. Th corresponds to the above-described first tension.
When the tension is stable, as described above, the controller 26 moves the traverse guide 22 and the yarn threading guide 27 to their respective yarn threading positions (step S103; above-described yarn threading control; see FIG. 8). As a result, the yarns Y are threaded to the respective slits S of the bobbins B2. At the moment when the yarn Y enters the bottom of the slit S (i.e., the inner edge in the radial direction of the bobbin B), the running path of the yarn Y is slightly shortened. As a result, the circumferential speed of the yarn Y decreases and the tension temporarily decreases (see a time t2 in FIG. 10). Thereafter, the tension applied to the yarn Y increases as the yarn Y is caught by the slit S, and the tension is maximized (see a time t3 in FIG. 10). Furthermore, at this time, the yarn Y on the package P1 side is cut and then handed over to the bobbin B2. In other words, the time t3 is a time when the yarn Y is handed over to the bobbin B2.
After starting the yarn threading control (i.e., after the time t1 at which the tension becomes stable), the controller 26 determines whether a predetermined first time has elapsed (step S104). The first time is a certain length of time that is set in advance by the controller 26, for example. The first time is an estimated value of the length of time from the time t1 to the time t3, for example. In actual bobbin switching, however, the length of time from the time t1 to the time t3 may not be the same every time. The first time may be the longest possible time from the start of the yarn threading control to the capture of the yarn Y by the slit S, for example.
The controller 26 waits for the elapse of the first time (No in the step S104). When the first time elapses (Yes in the step S104), the controller 26 starts the control (preliminary tension control in the step S105) of the tension of the yarn Y based on a measurement result of the tension of the yarn Y by the tensiometer 28 (see FIG. 1). The preliminary tension control is control that starts after the start of bunch winding on the bobbin B2 and before the start of the normal control of causing the traverse device 30 to traverse the yarn Y. The tension immediately after the elapse of the first time from the time t1 (see, e.g. the time t3 in FIG. 10) is much higher than the maximum allowable tension Ta. When the first time elapses from the time t1, it is possible to assume that the bunch winding on the bobbin B2 has already started. The controller 26 controls the winding motor 102B to decrease the circumferential speeds of the bobbins B2 to be lower than the circumferential speeds at the start of the preliminary tension control so that the measured value of the tension reaches the target tension Tt. As a result, the winding speeds of the yarns Y become lower than the winding speeds at the start of the preliminary tension control, and the force of pulling the yarns Y toward the bobbins B2 is lowered. The tension is therefore decreased.
After the start of the preliminary tension control, the controller 26 determines whether a predetermined second time has elapsed (step S106). The second time, for example, has a certain length of time which is set in advance. The second time is, for example, an estimated time from the start of the preliminary tension control to a time point at which the tension of the yarn Y becomes substantially equal to the target tension Tt (see, e.g., the time t4 in FIG. 10). The controller 26 waits for the elapse of the second time (No in the step S106). When the second time elapses (Yes in the step S106), the controller 26 controls the traverse device 30 to start traversal for the winding operation (step S107). In this way, the control in the bobbin switching is performed.
As described above, the bunch winding on the bobbin B2 has already started at the start of the preliminary tension control. Furthermore, the bunch winding on the bobbin B2 has already finished at the start of the traversal. Therefore, when or after the finish of the bunch winding of the yarn Y on the bobbin B2, the controller 26 has already started the preliminary tension control.
As described above, the controller 26 performs the preliminary tension control. With this arrangement, it is possible to control the tension applied to the yarn Y based on a measurement result of the tension, before the start of the formation of a yarn layer YL. On this account, as compared to a case where such control is not performed, it is possible to arrange the tension applied to the yarn Y at the start of the formation of the yarn layer YL to get close to a desired tension. It is therefore possible to improve the quality of the innermost layer of the yarn Y in the package P.
In the preliminary tension control, the controller 26 controls the winding motor 102 to decrease the winding speed of the yarn Y to be lower than the winding speed at the start of the preliminary tension control. With this arrangement, it is possible to decrease the tension before the start of the formation of the yarn layer YL. It is therefore possible to reliably improve the quality of the innermost layer of the yarn Y in the package P.
Furthermore, the controller 26 performs the preliminary tension control when or after at least the bunch winding of the yarn Y on the bobbin B finishes. It is therefore possible to stably perform the preliminary tension control.
In the preliminary tension control, the controller 26 controls the winding motor 102 so that the tension of the yarn Y reaches the target tension. With this arrangement, it is possible to cause the tension of the yarn Y to reach the target tension in the normal control, at the start of the formation of the yarn layer YL. It is therefore possible to improve the quality of the innermost layer of the yarn Y in the package P, in the same manner as the quality of the layers of the yarn Y, which are on the outer side in the radial direction of the innermost layer in the package P.
In the normal control, the controller 26 controls at least one of the traverse device 30 or the winding motor 102, based on a result of measurement of the tension by the tensiometer 28. To put it differently, the control can be flexibly done because the number of control targets in the normal control is large as compared to the preliminary tension control. It is therefore possible to further effectively improve the quality of the innermost layer of the yarn Y in the package P.
Furthermore, the traverse guide 22 is arranged to be movable to the outside of the traverse area T in the front-rear direction (axial direction of the bobbin B). This allows the traverse device 30 (traverse unit) to function as part of the bunch winding unit. It is therefore possible to reduce the number of components constituting the yarn winding apparatus 13 as compared to a case where the traverse unit and the bunch winding unit are independent from each other.
The traverse motor 31 of the traverse device 30 is a servo motor. This makes it possible to accurately control the position of the traverse guide 22. It is therefore possible to further accurately estimate the action of the yarn Y before and after the bunch winding. On this account, the accuracy of, for example, the timing to start the preliminary tension control can be improved.
The following will describe modifications of the above-described embodiment. The members identical with those in the embodiment above will be denoted by the same reference numerals and the explanations thereof may not be repeated.

(1) In the embodiment above, after the start of the preliminary tension control, the controller 26 causes the traverse device 30 to start the traversal for the winding operation at a timing when the tension of the yarn Y becomes substantially equal to the target tension Tt. However, the disclosure is not limited to this. The controller 26 may, for example, be on standby until the tension of the yarn Y becomes equal to or lower than the maximum allowable tension Ta (see a time t4' in FIG. 10) after the start of the preliminary tension control.
(2) In the embodiment above, the controller 26 starts the preliminary tension control when the yarn Y is handed over to the bobbin B2. However, the disclosure is not limited to this. When the yarn Y is handed over to the bobbin B2, typically, the yarn Y is bunch-wound on the bobbin B2. Typically, when bunch winding is performed on the bobbin B, the tension tends to be unstable (see, e.g., the time t3 and thereafter in FIG. 11). On this account, the controller 26 may start the preliminary tension control when or after, for example, the bunch winding on the bobbin B finishes (see the time t5 in FIG. 11). In other words, the controller 26 may perform the preliminary tension control only when or after the bunch winding finishes, for example.
(3) In the embodiment above, the controller 26 is configured to control the winding motor 102 to decrease the winding speed of the yarn Y in the preliminary tension control. However, the disclosure is not limited to this. The controller 26 may increase the winding speed of the yarn Y as necessary in the preliminary tension control. A case where the winding speed needs to be increased is, for example, a case where the tension of the yarn Y unintentionally becomes lower than the target tension Tt in the preliminary tension control.
(4) In the embodiment above, the traverse guide 22 is arranged to be movable to the outside of the traverse area T in the front-rear direction (axial direction of the bobbin B). However, the disclosure is not limited to this. Instead of such a traverse guide 22, a yarn gathering guide (not illustrated) may be provided to move the yarn Y to the outside of the traverse area T in the front-rear direction. In the arrangement in which the yarn gathering guide is provided, the traverse guide 22 may be able to move the yarn Y in the front-rear direction only in the traverse area T. In this case, a combination of the winding motor 102 and the yarn gathering guide is equivalent to the bunch winding unit of the present invention.
(5) In the embodiment above, the traverse device 30 includes a servo motor. However, the disclosure is not limited to this. The traverse motor 31 may not be able to detect information regarding the position of the traverse guide 22 in the axial direction. In this case, another device that is able to detect information regarding the position of the traverse guide 22 in the axial direction may be provided. Alternatively, such a device that is able to detect information regarding the position of the traverse guide 22 in the axial direction may not be provided.

Claims

A yarn winding apparatus (13) configured to form a package (P) by winding a yarn (Y) onto a take up tube (B), the yarn winding apparatus (13) comprising:
a rotational driving unit (102) which is configured to rotationally drive the take up tube (B);

a traverse unit (30) which is configured to traverse the yarn (Y) in an axial direction of the take up tube (B), in a predetermined traverse area (T) where a yarn layer (YL) of the yarn (Y) wound onto the take up tube (B) is formed;

a bunch winding unit which is configured to perform bunch winding of the yarn (Y) at a part of the take up tube (B) outside the traverse area (T) in the axial direction, before the yarn layer (YL) is formed;

a tension measurement unit (28) which is configured to measure tension of the yarn (Y) which is running toward the take up tube (B); and

a controller (26),

after the bunch winding starts and before normal control of causing the traverse unit (30) to traverse the yarn (Y) starts, the controller (26) starting preliminary tension control of controlling winding speed of the yarn (Y) by the rotational driving unit (102) based on a result of measurement of the tension by the tension measurement unit (28).
The yarn winding apparatus (13) according to claim 1, wherein, in the preliminary tension control, the controller (26) decreases the winding speed of the yarn (Y) to be lower than the winding speed at the start of the preliminary tension control.
The yarn winding apparatus (13) according to claim 1 or 2, wherein, the controller (26) starts the preliminary tension control when or after the bunch winding is completed.
The yarn winding apparatus (13) according to any one of claims 1 to 3, wherein, in the preliminary tension control, the controller (26) controls the rotational driving unit (102) so that the tension of the yarn (Y) reaches a target tension that is a predetermined target value of the tension of the yarn (Y) in the normal control.
The yarn winding apparatus (13) according to any one of claims 1 to 4, wherein, in the normal control, the controller (26) controls at least one of the traverse unit (30) or the rotational driving unit (102) based on a result of measurement of the tension by the tension measurement unit (28).
The yarn winding apparatus (13) according to any one of claims 1 to 5, wherein,
the traverse unit (30) includes a traverse guide (22) which is configured to be able to reciprocate along the axial direction and is configured to guide the yarn (Y) to the take up tube (B), and

the traverse guide (22) is configured to be movable to outside of the traverse area (T) in the axial direction.
The yarn winding apparatus (13) according to claim 6, wherein,
the traverse unit (30) includes a servo motor (31) which is configured to be able to drive and move the traverse guide (22) and to be able to detect information regarding a position in the axial direction of the traverse guide (22).