Yarn winding machine with yarn slack eliminating roller

Abstract

 A fine spinning machine (1) includes a winding device (12) adapted to wind a traveling yarn and a slack eliminating device (8) adapted to temporarily accumulate the yarn to be wound by the winding device (12). The slack eliminating device(8) includes a slack eliminating roller (30) (yarn accumulating roller) that is rotatable around which the yarn is wound, and a sensor (37) adapted to detect an excessively wound state in which the yarn is wound around a range beyond a yarn accumulating portion (40) (normal winding range) of the slack eliminating roller (30).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to a yarn winding machine that winds a traveling yarn to form a winding package.

2. Description of the Related Art

[0002] Conventionally, in a field of a yarn winding machine that winds a traveling yarn to form a package, there is a yarn winding machine including a yarn accumulating device that temporarily accumulates the yarn to be wound by the winding device. For example, Japanese Unexamined Patent Publication No. 2009-242041 (FIG. 1, paragraph 0025) discloses a fine spinning machine including a fine spinning device, a winding device that winds the yarn fed from the fine spinning device, and a yarn accumulating device (slack eliminating device) that is disposed between the fine spinning device and the winding device.

[0003] The yarn accumulating device includes a yarn accumulating roller (yarn slack eliminating roller) around which the yarn is wound and a sensor (wound amount sensor) that detects an amount of the yarn wound around the yarn accumulating roller. When a predetermined amount of yarn is wound around the yarn accumulating roller, the yarn slack is eliminated and a yarn tension is stabilized. As a result, a high-quality package can be formed by the winding device.

[0004] In the yarn accumulating roller described above, the yarn wound amount depends on a difference between a speed of the yarn supplied from upstream of the yarn accumulating roller and a speed of the yarn fed downstream from the yarn accumulating roller (that is, the winding speed of the winding device). However, the wound amount (wound range) of the yarn accumulating roller is gradually increased when the winding speed becomes lower than the speed of the yarn supplied to the yarn accumulating roller. As a result, the yarn accumulating roller becomes an excessively wound state in which the yarn is wound around a range beyond a normal winding range. At this time, the upstream yarn tension becomes excessive, which results in a problem in that yarn quality is degraded. Therefore, it is preferred that the excessively wound state is promptly detected.

[0005] The yarn accumulating device disclosed in Japanese Unexamined Patent Publication No. 2009-242041 includes a sensor that detects the wound amount of the yarn accumulating roller. However, the sensor is used to maintain the wound amount of the yarn accumulating roller at a predetermined amount during winding of the package. Accordingly, Japanese Unexamined Patent Publication No. 2009-242041 does not disclose at all the detection of the excessively wound state in which the yarn is wound from one end portion to the other end portion of the yarn accumulating roller.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a yarn winding machine that can detect the excessively wound state of the yarn accumulating roller. This object is achieved by a yarn winding machine according to claim 1.

[0007] According to a first aspect of the invention, a yarn winding machine includes a winding device adapted to wind a traveling yarn and a yarn accumulating device adapted to temporarily accumulate the yarn to be wound by the winding device. The yarn accumulating device includes a yarn accumulating roller and an excessive winding detecting sensor. The yarn accumulating roller is rotatable and the yarn is wound around the yarn accumulating roller. The excessive winding detecting sensor detects an excessively wound state in which the yarn is wound beyond a normal winding range of the yarn accumulating roller to a range where yarn quality is influenced.

[0008] With such a configuration, because the excessive winding detecting sensor can detect the excessively wound state, the state in which the yarn tension becomes excessive at the upstream of the yarn accumulating roller can promptly be detected to prevent degradation of the yarn quality.

[0009] According to a second aspect of the invention, in the yarn winding machine according to the first aspect, the yarn accumulating roller includes a yarn accumulating portion, an upstream taper portion, and a downstream taper portion. A surface of the yarn accumulating portion constitutes the normal winding range. The upstream taper portion and the downstream taper portion are continuous to two end portions of the yarn accumulating portion. The yarn traveling from the upstream of the yarn accumulating device is wound to the upstream taper portion. The excessive winding detecting sensor detects the yarn wound around the range beyond the yarn accumulating portion.

[0010] When the yarn from the upstream is wound around the upstream taper portion, the wound yarn is moved to the yarn accumulating portion by a slope of the upstream taper portion, and the yarn is wound around the yarn accumulating portion (normal winding range) . When the yarn is further wound around the yarn accumulating portion, the yarn starts to ascend the upstream taper portion from the yarn accumulating portion. Because the upstream taper portion has a diameter larger than that of the yarn accumulating portion, once the yarn starts to be wound around the upstream taper portion for even a small amount, the yarn speed is rapidly increased. As a result, the yarn tension is rapidly increased at the upstream of the yarn accumulating roller. In the present invention, the yarn wound around the range beyond the yarn accumulating portion (normal winding range) is detected by the excessive winding detecting sensor, which allows early detection of the state in which the yarn starts to be wound around the upstream taper portion.

[0011] According to a third aspect of the invention, in the yarn winding machine according to the second aspect, a circular step portion is formed between the yarn accumulating portion and the downstream taper portion, and a diameter of the circular step portion is larger than a diameter of the downstream end portion of the yarn accumulating portion, and the excessive winding detecting sensor detects the yarn wound around the circular step portion.

[0012] Usually, there is a small probability that the yarn is wound beyond the yarn accumulating portion (normal winding range) to the range where the yarn quality is influenced. However, a determination of the excessively wound state is falsely made when the yarn is moved to such a range by some chance. Therefore, according to the present invention, the position where the excessive winding detecting sensor detects presence or absence of the yarn is designed such that the yarn is hardly moved until the excessively wound state is reached. That is, according to the present invention, the circular step portion is formed between the yarn accumulating portion and the downstream taper portion. A difference in height between the yarn accumulating portion and the circular step portion becomes a resistance against the movement of the yarn to the circular step portion.

[0013] The yarn is wound only around the yarn accumulating portion (normal winding range) when the wound amount is not very large. When the wound amount becomes large in the yarn accumulating portion, part of the yarn in the yarn accumulating portion is pressed to move onto the circular step portion. As a result, the false detection of the excessively wound state is prevented. Since the state immediately before the yarn starts to be wound around the upstream taper portion can be detected, the increase in yarn tension can be detected at an early stage.

[0014] According to a fourth aspect of the invention, in the yarn winding machine according to the second aspect, the excessive winding detecting sensor detects the yarn wound beyond the yarn accumulating portion and up to the upstream taper portion. As described above, because the upstream taper portion has the diameter larger than that of the yarn accumulating portion, once the yarn starts to be wound around the upstream taper portion, the yarn tension rapidly increases at the upstream of the yarn accumulating roller. According to the present invention, the state in which the yarn starts to be wound around the upstream taper portion, which directly links to the increase in yarn tension at the upstream, can reliably be detected.

[0015] According to a fifth aspect of the invention, the yarn winding machine according to any of the first to fourth aspects further includes a pneumatic spinning device, wherein the spun yarn fed from the spinning device is wound around the yarn accumulating roller. The pneumatic spinning device causes a swirling airflow to act on a fiber bundle fed from the upstream to twist the fiber bundle, thereby producing the spun yarn. If the yarn tension at downstream of the spinning device (that is, the yarn tension at upstream of the yarn accumulating roller) is high, it becomes difficult to twist the fiber in the spinning device, which results in a problem in that the yarn quality is degraded. Therefore, in the yarn winding machine including such a pneumatic spinning device, the present invention is adapted to promptly detect the excessively wound state of the yarn accumulating roller located downstream of the spinning device.

[0016] According to a sixth aspect of the invention, in the yarn winding machine according to the fifth aspect, the yarn accumulating roller receives the spun yarn fed from the spinning device and feeds the spun yarn to the winding device. That is, the yarn accumulating roller acts as a feed roller that receives the spun yarn fed from the spinning device and feeds the spun yarn to the winding device. In this case, if the yarn accumulating roller becomes the excessively wound state, the yarn pickup speed rapidly increases and the upstream yarn tension also becomes excessive. Therefore, it is preferable that the excessively wound state of the yarn accumulating roller is promptly detected.

[0017] According to a seventh aspect of the invention, the yarn winding machine according to any of the first to sixth aspects includes a control device adapted to control the winding device and the yarn accumulating device. When receiving a yarn detection signal from the excessive winding detecting sensor, the control device controls the winding device to wind the yarn wound around the yarn accumulating roller and then stops the winding device. Therefore, when the excessively wound state of the yarn accumulating roller is detected and the yarn winding machine (winding device) is stopped, the yarn wound around the yarn accumulating roller is wound by the winding device. As a result, an operator can eliminate work to remove the yarn (yarn waste) remaining on the yarn accumulating roller.

[0018] According to an eighth aspect of the invention, the yarn winding machine according to any of the first to sixth aspects further includes a control device adapted to control the winding device and the yarn accumulating device. When receiving a yarn detection signal from the excessive winding detecting sensor, the control device controls the winding device to stop under a state in which the yarn is remaining on the yarn accumulating roller. Therefore, when the excessively wound state of the yarn accumulating roller is detected and the yarn winding machine (winding device) is stopped, the yarn remains on the yarn accumulating roller. As a result, the operator can easily determine that the winding device has stopped due to the excessively wound state of the yarn accumulating roller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a front view of a fine spinning machine according to the present embodiment;

FIG. 2 is a side view of one spinning unit of the fine spinning machine of FIG. 1;

FIG. 3 is an enlarged view of a slack eliminating device (yarn accumulating device);

FIG. 4 is a front view of a slack eliminating roller (yarn accumulating roller);

FIG. 5A to FIG. 5C are views illustrating a state in which a yarn is wound around a surface of the slack eliminating roller;

FIG. 6 is a block diagram illustrating a control configuration of the fine spinning machine;

FIG. 7 is a view illustrating a state in which a yarn is wound around a surface of a slack eliminating roller according to a modification; and

FIG. 8A is a view illustrating a state in which a yarn is wound around a surface of a slack eliminating roller according to another embodiment, and FIG. 8B is an enlarged view illustrating vicinity of an upstream taper portion of FIG. 8A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0020] Embodiments of the present invention will be described below. As illustrated in FIG. 1, a fine spinning machine 1 (yarn winding machine) includes a plurality of spinning units 2 that are arranged in line, a yarn splicing cart 3 that is configured to travel along a direction in which the spinning units 2 are arranged, a blower box 4, and a motor box 5.

[0021] As illustrated in FIG. 1 and FIG. 2, each of the spinning units 2 includes a draft device 6, a spinning device 7, a yarn clearer 11, a slack eliminating device 8 (yarn accumulating device), and a winding device 12. Hereinafter, "upstream" and "downstream" mean upstream and downstream in a traveling direction of a yarn 16 during spinning.

[0022] The draft device 6 is provided near an upper end portion of a casing 13 of a main body of the fine spinning machine 1. A sliver 14 fed to the draft device 6 is drafted by the draft device 6 to form a fiber bundle 15. The fiber bundle 15 is spun by the spinning device 7 into spun yarn 16. The spun yarn 16 is wound by the winding device 12 at the downstream to form a package 17.

[0023] The draft device 6 includes four rollers, that is, a back roller 22, a third roller 23, a middle roller 25 around which an apron belt 24 is wound, and a front roller 26, which are disposed along the traveling direction of the sliver 14 (fiber bundle 15) in this order. The apron belt 24 is wound around the middle roller 25 and a tensor bar 27. The tensor bar 27 is urged towards a direction in which the tensor bar 27 is separated from the middle roller 25, thereby providing a predetermined tension to the apron belt 24.

[0024] Although the detailed configuration of the spinning device 7 is not illustrated, a pneumatic spinning device is used as the spinning device 7 in the present embodiment. In the pneumatic spinning device, the spun yarn 16 is produced while the fiber bundle 15 is twisted by utilizing a swirling airflow.

[0025] A cutter 10 and the yarn clearer 11 are provided at downstream of the spinning device 7. The yarn clearer 11 monitors a thickness of the traveling spun yarn 16 to detect a thin yarn portion and a thick yarn portion (yarn defect) of the spun yarn 16. The yarn defect detected by the yarn clearer 11 includes presence or absence of a foreign matter such as polypropylene in addition to the thin yarn portion and the thick yarn portion. When detecting the yarn defect, the yarn clearer 11 transmits a yarn defect detection signal to a unit control section 21 (see FIG. 6). Once receiving the yarn defect detection signal, the unit control section 21 actuates the cutter 10 to cut the spun yarn 16. Alternatively, the spun yarn 16 may be cut by stopping the draft device 6 or the spinning device 7 while a winding operation of the winding device 12 is continued. In this case, the cutter 10 can be omitted.

[0026] The slack eliminating device 8 is provided between the spinning device 7 and the winding device 12. The slack eliminating device 8 includes a slack eliminating roller 30 (yarn accumulating roller). By winding a predetermined amount of spun yarn 16 produced by the spinning device 7 around the slack eliminating roller 30, the slack eliminating device 8 adjusts a yarn tension at the winding package 17 side while temporarily accumulating the spun yarn 16. The slack eliminating device 8 also has a function of pulling the spun yarn 16 from the spinning device 7 towards the downstream to feed the spun yarn 16 to the winding device 12 by actively rotating the slack eliminating roller 30 around which the spun yarn 16 is wound. The details of the slack eliminating device 8 will be described later. A traveling detecting sensor 28 is provided at the downstream of the slack eliminating device 8. The traveling detecting sensor 28 detects the spun yarn 16 that travels towards the winding device 12.

[0027] As illustrated in FIG. 1, the winding device 12 includes a winding drum 18 and a cradle 19 that rotatably supports a bobbin. When the winding drum 18 is rotated while being in contact with a surface of the bobbin (or a yarn layer wound around the bobbin), the bobbin is rotated to wind the spun yarn 16 around the bobbin, thereby forming the package 17.

[0028] As illustrated in FIG. 1 and FIG. 2, the yarn splicing cart 3 includes a yarn splicing device 92, a suction pipe 93, and a suction mouth 94. As illustrated in FIG. 1, the yarn splicing cart 3 is provided to travel on a rail 91 provided on the casing 13 of the main body of the fine spinning machine 1. When the yarn runs out or the yarn is cut in the spinning unit 2, the yarn splicing cart 3 travels to such a spinning unit 2 and stops. While vertically swinging around a shaft, the suction pipe 93 sucks and catches the yarn end discharged from the spinning device 7 (upstream yarn end), and guides the yarn end to the yarn splicing device 92. While vertically swinging around the shaft, the suction mouth 94 sucks and catches the yarn end from the package 17 that is rotatably supported by the winding device 12 (downstream yarn end), and the suction mouth 94 guides the yarn end to the yarn splicing device 92. The yarn splicing device 92 splices the guided yarn ends. The suction pipe 93 and the suction mouth 94 are connected to a negative pressure source accommodated in the blower box 4, and the suction pipe 93 and the suction mouth 94 obtain a suction force from the negative pressure source in order to suck the yarn end.

[0029] The blower box 4 is disposed on one end side in the array direction in which the plurality of spinning units 2 are arranged. The negative pressure source including a blower and a filter is accommodated in the blower box 4. A cleaning suction pipe (not illustrated) for sucking and removing yarn waste and cotton waste, which are generated at the draft device 6 or the slack eliminating device 8, and the suction pipe 93 and suction mouth 94 of the yarn splicing cart 3 are connected to the negative pressure source.

[0030] The motor box 5 is disposed on the side opposite the blower box 4 with respect to the plurality of spinning units 2. Motors are accommodated in the motor box 5 in order to drive the front roller 26 and the middle roller 25 of the draft device 6 in the plurality of spinning units 2. A main control section 96 having a control panel 151 is provided in the motor box 5. The main control section 96 transmits and receives a signal to and from the unit control section 21 of the spinning unit 2 and the yarn splicing cart 3 to perform operation control and state monitoring of each of the spinning units 2 and the yarn splicing cart 3.

[0031] The slack eliminating device 8 will be described in detail. As illustrated in FIG. 3, the slack eliminating device 8 includes a slack eliminating roller 30 (yarn accumulating roller), a yarn hooking member 31, an upstream guide 32, a downstream guide 33, and two yarn detecting sensors (first yarn detecting sensor 34 and second yarn detecting sensor 37) .

[0032] The slack eliminating roller 30 is a metallic cylindrical roller. The slack eliminating roller 30 is rotatably supported by a bracket 35 fixed to the casing 13 of the fine spinning machine 1, and is rotated by a motor 36. The slack eliminating roller 30 has a yarn accumulating portion 40 (normal winding range) and two taper portions 41 and 42. The yarn accumulating portion 40 is located in the center in a rotational axis direction of the yarn accumulating roller 30, and the spun yarn 16 is wound around the yarn accumulating portion 40 during the normal winding state. The taper portions 41 and 42 are continuously provided to two end portions of the yarn accumulating portion 40, and outer diameters of the taper portions 41 and 42 are increased as the distance from the yarn accumulating portion 40 increases.

[0033] As illustrated in FIG. 3 and FIG. 4, a taper angle of the taper portion 42 located on the downstream side (the side from which the spun yarn 16 is unwound) is smaller than a taper angle of the taper portion 41 located on the upstream side (the side on which the spun yarn 16 is initially wound) . That is, a slope of the downstream taper portion 42 is moderate than a slope of the upstream taper portion 41. The spun yarn 16 from the spinning device 7 is wound around the upstream taper portion 41, and the upstream taper portion 41 exerts a function of moving the spun yarn 16 to the downstream. Accordingly, the slope of the upstream taper portion 41 is necessary to be increased to some extent. On the other hand, such a function is not required for the downstream taper portion 42. The slope of the downstream taper portion 42 is moderate in order to smoothly unwind the spun yarn 16 wound around the yarn accumulating portion 40. In the drawings, the yarn accumulating portion 40 is illustrated as a straight cylindrical shape of which outer diameter does not change in a length direction. However, the yarn accumulating portion 40 is actually formed in a taper shape in which the outer diameter is gradually decreased from the upstream toward the downstream. Therefore, a contact resistance of the spun yarn 16 with the surface of the slack eliminating roller 30 is decreased toward the downstream. In the yarn accumulating portion 40, the spun yarn 16 is also easily moved to the downstream.

[0034] As illustrated in FIG. 4, a circular step portion 40a is formed between a downstream end portion of the yarn accumulating portion 40 and the downstream taper portion 42. The diameter of the circular step portion 40a is larger than the diameter of the downstream end portion of the yarn accumulating portion 40. The reason why the circular step portion 40a is provided will be described later.

[0035] The yarn hooking member 31 has a leading-end shape that can engage (hook) the spun yarn 16. The yarn hooking member 31 is attached to the downstream end portion of the slack eliminating roller 30. The yarn hooking member 31 is rotated integrally with the slack eliminating roller 30, which allows the spun yarn 16 to be wound around an outer peripheral surface of the slack eliminating roller 30.

[0036] As illustrated in FIG. 3, the spun yarn 16 fed from the spinning device 7 is wound around the upstream taper portion 41 of the slack eliminating roller 30. The wound spun yarn 16 is fed to the downstream by the taper shape of the upstream taper portion 41. The spun yarn 16 is wound in parallel around the yarn accumulating portion 40 in the axial direction of the slack eliminating roller 30. Accordingly, the spun yarn 16 is temporarily accumulated on the yarn accumulating portion 40 of the slack eliminating roller 30. When the slack eliminating roller 30 is actively rotated by the motor 36, the wound spun yarn 16 is unwound from the downstream taper portion 42 and fed to the winding device 12. That is, the slack eliminating roller 30 also acts as a feed roller that feeds the spun yarn 16, which is fed from the spinning device 7, to the winding device 12.

[0037] As described above, the spinning device 7 causes the swirling airflow to act on the fiber bundle 15 to twist the fiber bundle 15, thereby producing the spun yarn 16. In order to lower the yarn tension at the downstream of the spinning device 7 to easily twist the fiber bundle 15 in the spinning device 7, the number of rotations of the slack eliminating roller 30 is adjusted such that a traveling speed of the spun yarn 16 fed from the slack eliminating roller 30 becomes slower than a traveling speed of the spun yarn 16 fed from the front roller 26.

[0038] The upstream guide 32 is provided on the bracket 35 supporting the slack eliminating roller 30, and the upstream guide 32 is disposed slightly upstream of the slack eliminating roller 30. The upstream guide 32 properly guides the spun yarn 16 to the outer peripheral surface of the slack eliminating roller 30. The upstream guide 32 also acts as a twist stopper that prevents transmission of the twist of the spun yarn 16 propagating from the spinning device 7 to the downstream.

[0039] Similarly to the upstream guide 32, the downstream guide 33 is provided on the bracket 35 and disposed downstream of the slack eliminating roller 30. The downstream guide 33 guides the spun yarn 16 unwound from the slack eliminating roller 30 to the winding device 12.

[0040] The two yarn detecting sensors 34 and 37 detect the spun yarn 16 on the surface of the slack eliminating roller 30 to detect the wound amount (accumulated amount) of the spun yarn 16. The two yarn detecting sensors 34 and 37 are a reflection type photosensor (photo interrupter) including a light emitting element and a light receiving element. Each of the yarn detecting sensors 34 and 37 irradiates the surface of the slack eliminating roller 30 with light emitted from the light emitting element and receives the light reflected from the surface of the slack eliminating roller 30 with the light receiving element. When the spun yarn 16 exists in the position of the slack eliminating roller 30 irradiated with the light, the light hits the spun yarn 16 and is reflected by the spun yarn 16. In this case, the light amount received by the light receiving element is reduced because a reflectance is lowered compared with the case where the spun yarn 16 does not exist and the light is directly reflected from the surface of the metallic slack eliminating roller 30. Therefore, whether the spun yarn 16 exits in the irradiation position (yarn detecting position) of the slack eliminating roller 30 is detected from the change in light amount received by the light receiving element.

[0041] As illustrated in FIG. 3, the first yarn detecting sensor 34 is disposed to irradiate light to a predetermined position in a central portion of the yarn accumulating portion 40. The first yarn detecting sensor 34 detects whether the spun yarn 16 is wound to the predetermined position in the yarn accumulating portion 40 and the predetermined amount of spun yarn 16 is accumulated. The unit control section 21 controls the rotating speed of the slack eliminating roller 30 and/or the winding speed of the winding device 12 based on an output signal of the first yarn detecting sensor 34. Therefore, as illustrated in FIG. 5A, the state is maintained in which the spun yarn 16 is wound around the slack eliminating roller 30 to the yarn detecting position (irradiated position) of the sensor 34.

[0042] In the present embodiment, as the wound amount increases, the spun yarn 16 tends to be wound around the upstream taper portion 41 from the yarn accumulating portion 40. The upstream taper portion 41 has the diameter lager than that of the yarn accumulating portion 40. Therefore, when the spun yarn 16 starts to be wound around the upstream taper portion 41, the pickup speed of the spun yarn 16 by the rotation of the slack eliminating roller 30 rapidly increases. As a result, the yarn tension rapidly increases at upstream of the slack eliminating roller 30. When the upstream yarn tension becomes excessive, quality of the spun yarn 16 is degraded. Particularly, when the spinning device 7 located upstream of the slack eliminating roller 30 is a pneumatic spinning device as in the present embodiment, if the yarn tension is excessively increased, there is a problem in that it is difficult to twist the fiber in the spinning device 7.

[0043] For example, the following situation is considered as a situation in which the spun yarn 16 is excessively wound around the slack eliminating roller 30.

[0044] There may be a situation where the winding speed of the package 17 is excessively low in the winding device 12. Usually, an excessively wound state is not generated in the slack eliminating roller 30 when the winding speed of the package 17 is determined such that the wound amount of the slack eliminating roller 30 becomes a predetermined amount. However, when a defective bobbin in which a recess is partially formed is used, a peripheral speed of the package 17 is decreased at the portion of the bobbin where the recess exists. Therefore, the actual traveling speed of the spun yarn 16 wound into the package 17 becomes slower than an assumed speed.

[0045] When the yarn tension fluctuates, the thickness of the spun yarn 16 also changes. Therefore, the state in which the yarn tension is excessively high can possibly be detected by the yarn clearer 11 that detects the thickness of the yarn. However, even if the yarn clearer 11 can detect the abnormal tension, the yarn clearer 11 is located upstream than the slack eliminating roller 30 in which the excessively wound state is generated, which is the cause of the increased yarn tension. Thus, when the yarn clearer 11 detects the abnormal tension, the wound amount has already become excessively large in the slack eliminating roller 30. As a result, a response to the abnormality becomes late. The fluctuation in yarn tension is actually very small, and the change in yarn thickness caused by the small fluctuation in yarn tension is hardly correctly detected by the yarn clearer 11 generally used. Therefore, the excessively wound state of the slack eliminating roller 30 that is a cause of the abnormal tension is preferable to be directly detected.

[0046] The first yarn detecting sensor 34 detects whether the spun yarn 16 is wound to the predetermined position in the central portion of the slack eliminating roller 30, but the first yarn detecting sensor 34 cannot detect the excessively wound state. Therefore, as illustrated in FIG. 3 and FIG. 4, in the present embodiment, aside from the first yarn detecting sensor 34, the second yarn detecting sensor 37 (excessive winding detecting sensor) is provided in order to detect the excessively wound state of the slack eliminating roller 30. The second yarn detecting sensor 37 is disposed such that the light emitting element emits light toward the surface of the circular step portion 40a provided between the downstream end portion of the yarn accumulating portion 40 and the downstream taper portion 42. The second yarn detecting sensor 37 detects whether the spun yarn 16 is wound around the circular step portion 40a.

[0047] The spun yarn 16 guided by the upstream taper portion 41 is moved to the yarn accumulating portion 40 along a sloped surface of the upstream taper portion 41, and the spun yarn 16 is wound around the slack eliminating roller 30 for the first time when reaching the yarn accumulating portion 40. The spun yarn 16 is further moved to the downstream by the gentle slope of the yarn accumulating portion 40 and by being pressed by the subsequent spun yarn 16 descending the upstream taper portion 41, and the spun yarn 16 is unwound from the slack eliminating roller 30 at a certain position of the yarn accumulating portion 40. As illustrated in FIG. 5A, in the state where the wound amount is relatively small, the spun yarn 16 is unwound before reaching the downstream end portion of the yarn accumulating portion 40 in the slack eliminating roller 30. Accordingly, the second yarn detecting sensor 37 does not detect the spun yarn 16.

[0048] When the wound amount increases, the spun yarn 16 reaches the downstream end portion of the yarn accumulating portion 40. However, the circular step portion 40a is provided between the downstream end portion and the downstream taper portion 42. The spun yarn 16 moved to the downstream hardly moves further because the circular step portion 40a acts as the resistance. Accordingly, as illustrated in FIG. 5B, first, the spun yarn 16 is densely wound around the yarn accumulating portion 40 that is located upstream than the circular step portion 40a.

[0049] When the spun yarn 16 is further wound from the state in FIG. 5B, the spun yarn 16 passes over the step of the circular step portion 40a and starts to ascend the surface of the circular step portion 40a as illustrated in FIG. 5C. At this time, the second yarn detecting sensor 37 detects the spun yarn 16 wound around the circular step portion 40a for the first time. That is, the second yarn detecting sensor 37 detects the excessively wound state in which the spun yarn 16 is wound around the range beyond the yarn accumulating portion 40 (normal winding range) of the slack eliminating roller 30. Therefore, the state in which the yarn tension becomes excessive at the upstream of the slack eliminating roller 30 can promptly be detected. As a result, the degradation of the yarn quality can be prevented by the proper response such as stopping the fine spinning machine 1 or the like. Even if the spun yarn 16 is wound around the circular step portion 40a, almost no spun yarn 16 is wound around the upstream taper portion 41 whose diameter is larger than that of the circular step portion 40a. Accordingly, the state immediately before the spun yarn 16 starts to be wound around the upstream taper portion 41 can be detected by detecting the spun yarn 16 of the circular step portion 40a. Accordingly, the increase in the upstream yarn tension can be prevented at an early stage.

[0050] During the normal package winding, the spun yarn 16 is wound only around the yarn accumulating portion 40 (normal winding range). Therefore, the circular step portion 40a may be omitted, and the second yarn detecting sensor 37 may detect the spun yarn 16 wound around the downstream end portion of the yarn accumulating portion 40 (i.e., detect the state immediately before the spun yarn 16 starts to be wound around the upstream taper portion 41) (see FIG. 7 in another embodiment) . However, even in the normal state, sometimes the spun yarn 16 is moved to the downstream end portion of the yarn accumulating portion 40 by some chance. For example, during the yarn splicing operation of the yarn splicing device 92, the spun yarn 16 fed from the spinning device 7 is wound around and accumulated on the slack eliminating roller 30, and the spun yarn 16 is wound around the entire range of the yarn accumulating portion 40. At this time, the spun yarn 16 exists up to the downstream end portion of the yarn accumulating portion 40. As a result, the second yarn detecting sensor 37 detects the spun yarn 16 to falsely determine that the excessively wound state is generated.

[0051] In the first embodiment, the circular step portion 40a is provided in the downstream end portion of the slack eliminating roller 30, and the difference in height with the circular step portion 40a becomes the resistance when the spun yarn 16 is moved from the central portion to the circular step portion 40a. Therefore, as illustrated in FIG. 5B, only when the spun yarn 16 is further wound under a state in which the density of the spun yarn 16 is high in the upstream portion of the yarn accumulating portion 40, part of the spun yarn 16 is pressed to move onto the circular step portion 40a. Accordingly, the second yarn detecting sensor 37 detects the presence or absence of the spun yarn 16 in the circular step portion 40a, which allows the excessively wound state to be detected while discriminating the excessively wound state from the normal wound state.

[0052] When the circular step portion 40a is excessively high, the resistance when the spun yarn 16 starts to be wound around the circular step portion 40a is increased. As a result, the spun yarn 16 may start to ascend not the circular step portion 40a but the upstream taper portion 41 when the wound amount is increased in the slack eliminating roller 30. Therefore, for example, the height of the circular step portion 40a is preferably similar to the yarn thickness of the spun yarn 16 such that the resistance is not excessively increased when the spun yarn 16 starts to be wound around the circular step portion 40a.

[0053] An electric configuration of the fine spinning machine 1 will be described below with reference to a block diagram of FIG. 6. As illustrated in FIG. 6, a main control section 96 that controls the entire fine spinning machine 1 is connected to the unit control section 21 of the plurality of spinning units 2 and a control section 50 of the yarn splicing cart 3 to perform the control and state monitoring of the plurality of spinning units 2 and the yarn splicing cart 3.

[0054] The unit control section 21 of the spinning unit 2 includes a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), and an input/output interface. The ROM stores a program executed by the CPU and data used in the program. The RAM temporarily stores data when the program is executed. The input/output interface inputs and outputs the data from and to the outside. In addition to the package winding process realized by controlling the spinning device 7 and the winding device 12, the main control section 96 and the unit control section 21 perform the following processes based on the sensor outputs of the first yarn detecting sensor 34 and second yarn detecting sensor 37.

[0055] During the spinning performed by the spinning device 7, the first yarn detecting sensor 34 detects whether the spun yarn 16 exists in the predetermined yarn detecting position on the outer peripheral surface in the central portion of the yarn accumulating portion 40 of the slack eliminating roller 30 (that is, whether the predetermined amount of spun yarn 16 is wound from the upstream end portion to the central portion of the yarn accumulating portion 40). When determining that the wound amount of spun yarn 16 is decreased, the unit control section 21 decreases the winding speed of the winding device 12 to always maintain a state in which at least the predetermined amount of spun yarn 16 is wound around the slack eliminating roller 30.

[0056] The second yarn detecting sensor 37 detects whether the spun yarn 16 exists in the circular step portion 40a provided in the downstream end portion of the yarn accumulating portion 40 of the slack eliminating roller 30 (that is, whether the excessively wound state in which the spun yarn 16 is densely wound from the upstream end portion to the downstream end portion of the yarn accumulating portion 40 is generated) . When determining that the slack eliminating roller 30 is in the excessively wound state, the unit control section 21 stops the spinning unit 2 to prevent the generation of the defective yarn caused by the increased yarn tension. That is, the unit control section 21 stops drafting of the sliver 14 by the draft device 6, the spinning by the spinning device 7, and the package winding by the winding device 12 in such a spinning unit 2.

[0057] Even if the second yarn detecting sensor 37 detects the excessively wound state, because the spun yarn 16 wound around the surface of the slack eliminating roller 30 at the time of detection is the yarn having the normal quality, there is no problem in winding such spun yarn 16 into the package 17. When the fine spinning machine 1 is stopped due to the excessively wound state, the main control section 96 may stop the winding device 12 after the spun yarn 16 on the surface of the yarn accumulating roller 30 is wound by the winding device 12. In this case, the spun yarn 16 that was wound around the slack eliminating roller 30 is completely wound by the winding device 12 when the spinning unit 2 is stopped. Accordingly, the operator can eliminate the work to remove the spun yarn 16 remaining on the slack eliminating roller 30.

[0058] Alternatively, the winding device 12 may be stopped under a state in which the spun yarn 16 is remaining on the surface of the slack eliminating roller 30 (before the spun yarn 16 is wound by the winding device 12). In this case, the spun yarn 16 is remaining on the slack eliminating roller 30 when the spinning unit 2 is stopped. Accordingly, the operator can easily determine that the spinning unit 2 has stopped due to the excessively wound state of the slack eliminating roller 30. For example, a package brake may be provided in each winding device 12 in order to forcibly stop the rotation of the package 17. As illustrated in FIG. 1, the fine spinning machine 1 of the present embodiment includes a line shaft that collectively drives the packages 17 of all the spinning units 2. When stopping one spinning unit 2, the package 17 of such spinning unit 2 is separated from the line shaft to stop the driving of the line shaft. At the same time, inertia rotation of the package 17 is promptly stopped by the package brake. Accordingly, the spinning unit 2 can be stopped under a state in which the spun yarn 16 is remaining on the slack eliminating roller 30.

[0059] Thereafter, the operator performs checking or maintenance in order to solve the cause of the excessively wound state of the slack eliminating roller 30. For example, the operator changes the setting of a feeding speed of the fiber bundle 15 of the draft device 6, changes the setting of the package winding speed of the winding device 12, or exchanges the defective bobbin.

[0060] Other embodiments in which various changes are made to the above-described embodiment will be described below. Same reference numeral is denoted to the component having the configuration similar to that of the above embodiment, and the description thereof is omitted.

[0061] 1) As described in the above embodiment, the probability that the spun yarn 16 is wound up to the downstream end portion of the yarn accumulating portion 40 is small during the normal package winding. Accordingly, as illustrated in FIG. 7, the circular step portion 40a may be omitted, and the second yarn detecting sensor 37 may detect the spun yarn 16 wound around the downstream end portion of the yarn accumulating portion 40 (that is, detect the state immediately before the spun yarn 16 starts to be wound around the upstream taper portion 41).

[0062] 2) As illustrated in FIG. 8A and FIG. 8B, the second yarn detecting sensor 37 may detect the spun yarn 16 that is wound around the upstream taper portion 41 beyond the yarn accumulating portion 40. In this case, the second yarn detecting sensor 37 can reliably detect the state in which the spun yarn 16 starts to be wound around the upstream taper portion 41 that is directly linked to the increase in the upstream yarn tension.

[0063] However, as illustrated in FIG. 8B, it is necessary to adjust the detecting position of the second yarn detecting sensor 37 with high accuracy such that the spun yarn 16a wound around the yarn accumulating portion 40 can correctly be distinguished from the spun yarn 16b that has been wound around the upstream taper portion 41 due to the excessively wound state. On the other hand, when the spun yarn 16 is detected in the circular step portion 40a as described in the above embodiment, it is not necessary to adjust the detecting position of the second yarn detecting sensor 37 with such high accuracy. Therefore, the second yarn detecting sensor 37 can be easily attached.

[0064] 3) In the above embodiment, by way of example, the spinning unit 2 is stopped in response to the detection of the excessively wound state of the slack eliminating roller 30 with the second yarn detecting sensor 37. Alternatively, another response may be performed. For example, when the rotating speed of the winding device 12 can independently be controlled in each of the plurality of spinning units 2, the excessively wound state may be resolved by increasing the winding speed of the winding device 12 of the spinning unit 2 in which the excessively wound state of the slack eliminating roller 30 is detected.

[0065] 4) In the above embodiment, the reflection type photosensors are used as the yarn detecting sensors 34 and 37 that detect the spun yarn 16 on the surface of the slack eliminating roller 30 by way of example. However, the present invention is not limited thereto, and various sensors having detection systems may be used as the yarn detecting sensors 34 and 37.

[0066] 5) In the above embodiment, the present invention is applied to the fine spinning machine by way of example. However, the present invention is not limited to the fine spinning machine, and the present invention can be applied to yarn winding machines of textile machines other than the fine spinning machine.

Claims

1. A yarn winding machine comprising:

a winding device (12) adapted to wind a traveling yarn, and

a yarn accumulating device (8) adapted to temporarily accumulate the yarn to be wound by the winding device (12),

wherein the yarn accumulating device (8) includes:

a yarn accumulating roller (30) that is rotatable around which the yarn is wound, and

an excessive winding detecting sensor (37) adapted to detect an excessively wound state in which the yarn is wound beyond a normal winding range (40) of the yarn accumulating roller (30).

2. The yarn winding machine according to claim 1, wherein the yarn accumulating roller (30) includes:

a yarn accumulating portion (40) of which a surface thereof is the normal winding range (40), and

an upstream taper portion (41) and a downstream taper portion (42) that are continuous to two end portions of the yarn accumulating portion (40), the yarn traveling from upstream of the yarn accumulating roller (30) is wound to the upstream taper portion (41), and

the excessive winding detecting sensor (37) detects the yarn wound around the range beyond the yarn accumulating portion (40).

3. The yarn winding machine according to claim 2, wherein a circular step portion (40a) is formed between the yarn accumulating portion (40) and the downstream taper portion (42), and a diameter of the circular step portion (40b) is larger than a diameter of a downstream end portion of the yarn accumulating portion (40), and
the excessive winding detecting sensor (37) detects the yarn wound around the circular step portion (40a).

4. The yarn winding machine according to claim 2, wherein the excessive winding detecting sensor (37) detects the yarn wound beyond the yarn accumulating portion (40) and up to the upstream taper portion (41).

5. The yarn winding machine according to any one of claim 1 through claim 3, further comprising a pneumatic spinning device (7),
wherein spun yarn fed from the spinning device (7) is wound around the yarn accumulating roller (30).

6. The yarn winding machine according to claim 5, wherein the yarn accumulating roller (30) receives the spun yarn fed from the spinning device (7) and feeds the spun yarn to the winding device (12).

7. The yarn winding machine according to any one of claim 1 through claim 6, further comprising a control device (21) adapted to control the winding device (12) and the yarn accumulating device (8),
wherein when receiving a yarn detecting signal from the excessive winding detecting sensor (37), the control device (21) controls the winding device (12) to wind the yarn wound around the yarn accumulating roller (30) and then controls to stop the winding device (12).

8. The yarn winding machine according to any one of claim 1 through claim 6, further comprising a control device (21) adapted to control the winding device (12) and the yarn accumulating device (8),
wherein when receiving a yarn detecting signal from the excessive winding detecting sensor (37), the control device (21) controls the winding device (12) to stop under a state in which the yarn is remaining on the yarn accumulating roller (30).

Drawing