JP2020172364A - Yarn unwinding assist device - Google Patents

Abstract

To provide a yarn unwinding assist device which can effectively suppress generation of sloughing and increase of unwinding tensile force.SOLUTION: A yarn unwinding assist device 20 assists unwinding of a yarn Y from a yarn feeding bobbin SB. The yarn unwinding assist device 20 includes a guide cylinder 50 arranged to cover a core tube of the yarn feeding bobbin SB. On an inner peripheral surface of the guide cylinder 50, a high friction material layer is provided which has a dynamic friction coefficient of 0.3 or more and 0.5 or less with respect to a cotton yarn.SELECTED DRAWING: Figure 3

Description

The present invention relates to a yarn unwinding assisting device that assists in unwinding a yarn from a bobbin.

Conventionally, an automatic winder that winds a thread on a winding bobbin while unwinding the thread from the thread feeding bobbin is known. Here, a balloon is formed around the thread feeding bobbin by the thread unwound from the thread feeding bobbin. The balloon is a part where the thread unwound from the thread feeding bobbin is swung around by centrifugal force. Here, when the unwinding speed of the yarn from the yarn feeding bobbin is increased, the balloon becomes larger and the centrifugal force of the balloon increases. As a result, a phenomenon in which the yarn comes out of the yarn feeding bobbin in an annular shape (so-called sluffing) occurs, and in particular, the latter half of the unwinding (for example, the remaining unwinding amount of the yarn feeding bobbin is 1/3). There is a risk of thread breakage due to an increase in unwinding tension (after that point).

Therefore, the automatic winder is provided with a thread unwinding assisting device that assists the unwinding of the thread in order to physically suppress the balloon. The thread unwinding assisting device includes a guide tube that covers the core tube of the thread feeding bobbin. The thread unwinding assisting device prevents the thread from being excessively swung by bringing the guide tube into contact with the balloon. A thread unwinding assisting device including such a guide cylinder is described in, for example, Patent Document 1.

Japanese Unexamined Patent Publication No. 2013-67459

In the thread unwinding assisting device as described above, there is room for further improvement in suppressing the occurrence of sluffing and the increase in unwinding tension described above.

Therefore, one aspect of the present invention is to provide a yarn unwinding assisting device capable of effectively suppressing the occurrence of sluffing and the increase in unwinding tension.

One aspect of the present invention is a thread unwinding assisting device that assists in unwinding a thread from a bobbin, and includes a guide cylinder arranged so as to cover the core tube of the bobbin, and the inner peripheral surface of the guide cylinder A high friction portion having a coefficient of dynamic friction with respect to cotton yarn of 0.3 or more and 0.5 or less is provided. For example, the cotton yarn is a yarn having an English cotton count of Ne30.

In this yarn unwinding assisting device, a high friction portion having a coefficient of dynamic friction with respect to cotton yarn of 0.3 or more and 0.5 or less is provided on the inner peripheral surface of the guide cylinder. Due to such a high friction portion, the slipperiness of the thread on the inner circumference of the guide cylinder is reduced as compared with the conventional material (for example, the salt bath soft-nitrided pickled steel sheet having a dynamic friction coefficient of 0.25). Can be made to. That is, the high friction portion makes it possible to appropriately brake the thread unwound from the bobbin. As a result, it is possible to suppress the unintentional slack of the thread unwound from the bobbin and suppress the expansion of the balloon. As a result, the occurrence of sluffing and the increase in unwinding tension can be effectively suppressed.

The guide cylinder has a cylindrical first cylinder portion extending along a predetermined reference axis and a bobbin out of both ends along the reference axis in the first cylinder portion while extending along the reference axis. It has a second cylinder portion connected to the upstream end portion of the thread unwound from the traveling direction, and the second cylinder portion is the first from the end portion on the side connected to the first cylinder portion. It has a tapered shape that gradually expands toward the end opposite to the end connected to the cylinder, even if the high friction portion is provided at least on the inner peripheral surface of the second cylinder. Good. According to this configuration, it is possible to appropriately apply the brake to the yarn in the second cylinder portion which is the introduction port of the yarn into the guide cylinder. As a result, the expansion of the balloon of the thread can be effectively suppressed.

The high friction portion may be provided on both the inner peripheral surface of the first cylinder portion and the inner peripheral surface of the second cylinder portion. According to this configuration, the slipperiness of the yarn can be reduced on the inner circumferences of both the first cylinder portion and the second cylinder portion. Thereby, the expansion of the balloon of the thread can be suppressed more effectively.

A low friction portion having a coefficient of dynamic friction with respect to the cotton thread smaller than that of the high friction portion may be provided on the inner peripheral surface of the first cylinder portion. According to this configuration, the occurrence of sluffing can be suppressed by the high friction portion and the increase in the unwinding tension can be suppressed by the low friction portion according to the progress of unwinding of the yarn from the bobbin.

The coefficient of dynamic friction of the low friction portion with respect to the cotton thread may be 0.1 or more and less than 0.25. According to this configuration, the slipperiness of the yarn on the inner circumference of the first cylinder portion is improved as compared with the conventional material (for example, the salt bath soft-nitrided pickled steel sheet having a dynamic friction coefficient of 0.25). Can be made to. As a result, the increase in the unwinding tension of the yarn in the latter half of the unwinding can be suppressed more effectively.

According to one aspect of the present invention, it is possible to provide a yarn unwinding assisting device capable of effectively suppressing the occurrence of sluffing and the increase in unwinding tension.

FIG. 1 is a front view of an automatic winder including a yarn unwinding assisting device according to an embodiment. FIG. 2 is a side view of the take-up unit. FIG. 3 is a side view of the thread unwinding assisting device around the guide cylinder. FIG. 4 is a cross-sectional view of the guide cylinder. FIG. 5 is a cross-sectional view of a first modification of the guide cylinder. FIG. 6 is a cross-sectional view of a second modification of the guide cylinder.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 1, the automatic winder 1 includes a plurality of winding units 3 arranged side by side, a machine base control device 5, and a ball lifting device 7.

The machine stand control device 5 can communicate with each of the plurality of winding units 3. The operator of the automatic winder 1 can collectively manage a plurality of winding units 3 by appropriately operating the machine base control device 5. The machine stand control device 5 is provided with a display screen 5a and an input key 5b. The display screen 5a can display information about the setting contents and / or the state of the winding unit 3. The setting work of the take-up unit 3 is performed when the operator performs an appropriate operation using the input key 5b.

Each of the plurality of winding units 3 winds the yarn Y on the winding bobbin WB while unwinding the yarn Y from the yarn feeding bobbin (bobbin) SB and swinging the yarn Y. In this way, the take-up unit 3 forms the package P. The thread Y may include a core thread. The core yarn is, for example, a monofilament yarn or the like.

When the package P is fully wound (a state in which a specified amount of yarn is wound) in each of the plurality of winding units 3, the ball lifting device 7 travels to the position of the winding unit 3 and is fully wound. The winding package is removed from the winding unit 3, and an empty winding bobbin WB is set in the winding unit 3.

Next, the configuration of the take-up unit 3 will be described with reference to FIG. As shown in FIG. 2, each of the plurality of winding units 3 includes a unit control unit 10, a yarn feeding device 12, and a winding device 14.

The unit control unit 10 includes, for example, a processor such as a CPU (Central Processing Unit) and a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). A program for controlling each configuration of the take-up unit 3 is stored in the memory. The processor executes a program stored in memory. The unit control unit 10 controls each configuration of the take-up unit 3 in cooperation with hardware and software. The unit control unit 10 is configured to be able to communicate with the machine base control device 5. As a result, the operation of the plurality of winding units 3 provided in the automatic winder 1 can be centrally managed by the machine base control device 5.

The thread feeding device 12 is a support mechanism that supports the thread feeding bobbin SB mounted on the transport tray at a predetermined position. The thread Y is unwound from the thread feeding bobbin SB, and the thread Y is pulled out from the thread feeding bobbin SB upward. As a result, the yarn feeding device 12 supplies the yarn Y. The yarn feeding device 12 is not limited to the transport tray type, and may be, for example, a magazine type.

The take-up device 14 includes a cradle 16 and a take-up drum 18. The cradle 16 has a pair of rotary supports (not shown). The cradle 16 rotatably supports the take-up bobbin WB (or package P) by sandwiching the take-up bobbin WB with the rotation support portion. The cradle 16 can be switched between a state in which the supporting package P is in contact with the take-up drum 18 and a state in which the package P is separated from the take-up drum 18.

The take-up drum 18 traverses the thread Y on the surface of the package P and rotates the package P. The take-up drum 18 is rotationally driven by a drum drive motor (not shown). The package P is driven to rotate by rotationally driving the take-up drum 18 with the outer peripheral surface of the package P in contact with the take-up drum 18. Further, a spiral twill groove is formed on the outer peripheral surface of the take-up drum 18. The thread Y unwound from the thread-feeding bobbin SB is wound around the surface of the package P while being traversed by a twill groove with a constant width. Thereby, the package P having a constant winding width can be formed.

Each of the plurality of winding units 3 includes the yarn unwinding assisting device 20 and the tension applying device 22 in this order from the yarn feeding device 12 side in the yarn traveling path between the yarn feeding device 12 and the winding device 14. A tension detection device 24, a thread splicing device 26, a thread monitoring device 28, and a wax applying device 30 are provided. A first capture guide device 32 and a second capture guide device 34 are arranged in the vicinity of the thread joining device 26.

The thread unwinding assisting device 20 includes a guide cylinder 50 arranged so as to cover the core tube of the thread feeding bobbin SB. The guide cylinder 50 has a substantially tubular shape, and is arranged so as to come into contact with the balloon of the yarn Y formed on the upper portion of the yarn layer of the yarn feeding bobbin SB. The balloon is a portion where the thread Y unwound from the thread feeding bobbin SB is swung around by centrifugal force. By bringing the guide cylinder 50 into contact with the balloon, it is possible to prevent the thread Y from being excessively swung by coming into contact with the thread Y of the balloon portion. As a result, the thread Y can be appropriately unwound from the thread feeding bobbin SB.

The tension applying device 22 applies a predetermined tension to the traveling thread Y. In the present embodiment, the tension applying device 22 is a gate type in which movable comb teeth are arranged with respect to fixed comb teeth. The comb teeth on the movable side are urged so that the comb teeth are in mesh with each other. The tension applying device 22 applies tension to the thread Y by passing the thread Y while bending between the comb teeth in the meshed state. The operation of the tension applying device 22 is controlled by the unit control unit 10.

The tension detection device 24 detects (measures) the tension of the traveling thread Y between the thread feeding device 12 and the winding device 14. The tension detection device 24 outputs a tension measurement signal indicating a measured value of the tension of the thread Y to the unit control unit 10.

When the yarn Y is split between the yarn feeder 12 and the take-up device 14 for some reason, the yarn joining device 26 includes the yarn Y (bobbin thread) on the yarn feeder 12 side and the take-up device. The thread Y (upper thread) on the 14 side is spliced. In the present embodiment, the yarn splicing device 26 is configured as a splicer device that twists yarn ends with each other by a swirling air flow generated by compressed air.

The thread monitoring device 28 monitors the state of the thread Y traveling on the thread path, and detects the presence or absence of a thread defect based on the monitored information. The thread monitoring device 28 detects, for example, an abnormality in the thickness of the thread Y and / or a foreign substance contained in the thread Y as a thread defect. The thread monitoring device 28 also detects thread breakage, that is, the presence or absence of thread Y in the thread path. A cutter 29 for cutting the yarn Y is provided in the vicinity of the yarn monitoring device 28. The cutter 29 is operated by the thread monitoring device 28.

The wax applying device 30 is arranged between the winding device 14 and the yarn monitoring device 28. The wax applying device 30 applies wax to the yarn Y traveling from the thread monitoring device 28 toward the winding device 14.

Next, the details of the configuration of the thread unwinding assisting device 20 will be described. As shown in FIG. 3, the thread unwinding assisting device 20 assists the unwinding of the thread Y from the thread feeding bobbin SB above the thread feeding bobbin SB supported in an upright state by the thread feeding device 12. .. The yarn unwinding assisting device 20 controls the size of the balloon formed by the yarn Y unwound from the yarn feeding bobbin SB, and applies an appropriate tension to the yarn Y.

Specifically, the thread unwinding assisting device 20 includes a guide cylinder 50, a fixed cylinder 54, and an elevating mechanism 56. The fixed cylinder 54 is a substantially cylindrical member having upper and lower ends open. The fixed cylinder 54 is fixed to the frame of the winding unit 3 via the holder 58. A thread guide 55 is provided at the lower end of the fixed cylinder 54.

The guide cylinder 50 is a substantially tubular member having upper and lower ends open. The guide cylinder 50 is supported by the elevating mechanism 56 via the holder 57. The lower part of the fixed cylinder 54 is inserted inside the upper part of the guide cylinder 50. The guide cylinder 50 is moved up and down by the elevating mechanism 56 so as to cover the upper part of the thread feeding bobbin SB. The central axis of the thread feeding bobbin SB coincides with the central axis of the fixed cylinder 54 and the guide cylinder 50. The thread Y unwound from the thread feeding bobbin SB passes through the internal space of the guide cylinder 50.

Further, the yarn unwinding assisting device 20 includes a sensor that detects the height of the chase portion T of the yarn feeding bobbin SB. The position of the chase portion T is lowered by unwinding the thread Y. The elevating mechanism 56 lowers the guide cylinder 50 according to the height of the chase portion T detected by the sensor. As a result, the guide cylinder 50 can be lowered (movable) according to the unwinding of the thread Y from the thread feeding bobbin SB.

The fixed cylinder 54 regulates the spread of the balloon in a fixed state. The guide cylinder 50 moves following the unwinding of the yarn Y from the yarn feeding bobbin SB to regulate the spread of the balloon. In this way, the fixed cylinder 54 and the guide cylinder 50 assist the unwinding of the thread Y by restricting the spread of the balloon.

Next, the details of the guide cylinder 50 will be described. As described above, the guide cylinder 50 shown in FIGS. 3 and 4 assists in unwinding the yarn Y from the yarn feeding bobbin SB. The guide cylinder 50 is formed of, for example, a salt bath soft-nitrided pickled steel plate (SPHC-P). The guide cylinder 50 includes a first cylinder portion 51 and a second cylinder portion 52. The first tubular portion 51 has a cylindrical shape extending along the central axis (predetermined reference axis) L. That is, the cross-sectional shape of the first tubular portion 51 in the direction orthogonal to the central axis L is an annular shape. In the present embodiment, the length of the first tubular portion 51 along the central axis L is longer than the length of the second tubular portion 52 along the central axis L.

The second tubular portion 52 extends along the central axis L. The second cylinder portion 52 is arranged at the lower end portion of the first cylinder portion 51. That is, the second tubular portion 52 is on the upstream side in the traveling direction of the yarn Y unwound from the yarn feeding bobbin SB among both end portions (upper end portion and lower end portion) along the central axis L in the first cylinder portion 51. It is located at the end (lower end) of.

The second tubular portion 52 has a tapered shape whose diameter increases toward the lower end portion. That is, the second cylinder portion 52 has an end portion (lower end portion) opposite to the end portion (upper end portion) on the side connected to the first cylinder portion 51 to the end portion on the side connected to the first cylinder portion 51. It has a tapered shape that gradually expands toward the part). Further, the cross-sectional shape of the second tubular portion 52 in the direction orthogonal to the central axis L is an annular shape.

A high friction material layer 61 (high friction portion) having a coefficient of dynamic friction with respect to cotton yarn of 0.3 or more and 0.5 or less is provided on the inner peripheral surface of the guide cylinder 50. Here, the above-mentioned coefficient of dynamic friction is a measured value by the measuring method specified in "JIS L 1095: 2010 General Spinning Thread Test Method, Chapter 9.11, Coefficient of Friction". In the following description, the "coefficient of dynamic friction with respect to cotton thread" is simply referred to as "coefficient of dynamic friction". In the present embodiment, the cotton yarn is a yarn having an English cotton count of Ne30.

In the present embodiment, a high friction material layer 61 formed of a high friction material (for example, a rubber sheet) is provided on the entire inner peripheral surface 52a of the second tubular portion 52. On the other hand, in the present embodiment, the inner peripheral surface 51a of the first cylinder portion 51 is exposed to the internal space of the guide cylinder 50. That is, the high friction material layer 61 is not provided on the inner peripheral surface 51a of the first tubular portion 51. Here, the coefficient of kinetic friction of the inner peripheral surface 51a (that is, the pickled steel sheet soft-nitrided in the salt bath) is 0.25. That is, on the inner peripheral surface (inner peripheral surface 52a in this embodiment) of the guide cylinder 50, a high friction material layer 61 having improved frictional resistance as compared with a conventional material (salt bath soft nitrided pickled steel plate). Is provided.

In the thread unwinding assisting device 20 described above, the high friction material layer 61 is provided on the inner peripheral surface (inner peripheral surface 52a in the present embodiment) of the guide cylinder 50. With such a high friction material layer 61, the slipperiness of the thread Y on the inner circumference of the guide cylinder 50 is compared with that of a conventional material (for example, a salt bath soft nitrided pickled steel sheet having a dynamic friction coefficient of 0.25). Can be reduced. That is, the high friction material layer 61 makes it possible to appropriately brake the yarn Y unwound from the yarn feeding bobbin SB. As a result, it is possible to suppress unintended slackening of the thread Y unwound from the thread feeding bobbin SB and suppress the expansion of the balloon. As a result, the occurrence of sluffing and the increase in unwinding tension can be effectively suppressed.

Further, the high friction material layer 61 is provided at least on the inner peripheral surface 52a of the second tubular portion 52. As a result, the thread Y can be appropriately braked at the second cylinder portion 52, which is the port for introducing the thread Y into the guide cylinder 50. As a result, the expansion of the balloon of the thread Y can be effectively suppressed.

Further, the inner peripheral surface 51a of the first tubular portion 51 is provided with a low friction portion having a dynamic friction coefficient smaller than that of the high friction material layer 61. In the present embodiment, the inner peripheral surface 51a itself (the surface having a dynamic friction coefficient of 0.25) of the first tubular portion 51 functions as a low friction portion. According to this configuration, the high friction material layer 61 suppresses the occurrence of sluffing according to the progress of unwinding of the yarn Y from the yarn feeding bobbin SB, and the low friction portion (inner peripheral surface 51a) dissolves the yarn Y. It is possible to suppress an increase in the bobbin tension.

For example, in the first half of unwinding in which the amount of thread of the thread-feeding bobbin SB is large, the balloon of thread Y tends to be relatively large, and the influence of the balloon is dominant (the period in which sluffing is relatively likely to occur). The high friction material layer 61 provided on the tubular portion 52 can effectively suppress the expansion of the balloon of the thread Y. On the other hand, for example, in the latter half of unwinding when the thread amount of the thread-feeding bobbin SB is reduced (for example, after the remaining unwinding amount becomes a three-quarter ball with 1/3), the balloon of thread Y is compared with the first half of unwinding. It is thought that the effect of the balloon will be limited because it is difficult to grow. Therefore, in the latter half of the unwinding, the friction between the thread Y unwound from the thread feeding bobbin SB and the thread Y wound around the thread feeding bobbin SB (the thread Y before unwinding) is the unwinding tension of the thread Y. It is thought that the degree of contribution to the increase will increase. According to the guide cylinder 50, in the latter half of unwinding, the frictional resistance between the thread Y and the first cylinder portion 51 is set to the thread Y by the low friction portion (inner peripheral surface 51a) provided in the first cylinder portion 51. It can be made smaller than the frictional resistance with the second tubular portion 52. As a result, the movement of the thread Y unwound from the thread feeding bobbin SB in the first tubular portion 51 can be promoted, and the thread Y unwound from the thread feeding bobbin SB and the thread Y wound around the thread feeding bobbin SB The frictional resistance generated between the two can be reduced. As a result, it is possible to suppress an increase in unwinding tension.

However, the present invention is not limited to the above embodiment. For example, the thread unwinding assisting device 20 may include the guide cylinder 50A shown in FIG. 5 instead of the guide cylinder 50 described above. The guide cylinder 50A is different from the guide cylinder 50 in that the above-mentioned high friction material layer 61 is provided not only on the inner peripheral surface 52a of the second cylinder portion 52 but also on the inner peripheral surface 51a of the first cylinder portion 51. are doing. Specifically, in the guide cylinder 50A, the high friction material layer 61 is provided on both the inner peripheral surface 51a of the first cylinder portion 51 and the inner peripheral surface 52a of the second cylinder portion 52. According to this configuration, the slipperiness of the thread Y can be reduced on the inner circumferences of both the first cylinder portion 51 and the second cylinder portion 52. As a result, the expansion of the balloon of the thread Y can be suppressed more effectively.

Next, the results of analysis and experiments performed on the thread unwinding assisting device according to the examples (Examples 1 and 2) and the thread unwinding assisting device according to the comparative example are shown. The yarn unwinding assisting device according to the first embodiment is a yarn unwinding assisting device 20 provided with a guide cylinder 50 having a high friction material layer 61 having a dynamic friction coefficient of 0.4. The yarn unwinding assisting device according to the second embodiment is a yarn unwinding assisting device provided with a guide cylinder 50A having a high friction material layer 61 having a dynamic friction coefficient of 0.4. The yarn unwinding assisting device according to the comparative example has an inner peripheral surface 51a and an inner peripheral surface 52a having a dynamic friction coefficient of 0.25 in the entire inner circumference of the guide cylinder in which the high friction material layer 61 is omitted (that is, the entire inner circumference of the guide cylinder It is a thread unwinding assisting device equipped with a conventional structure in which is exposed. The conditions for analysis and experiment are as follows.
・ Winding speed of thread Y: 2000m / min (constant)
-Type of thread Y: Cotton thread with English cotton count Ne30-Bobbin length of thread feeding bobbin SB: 225 mm

<Frequency of severe sluffing>
The experimental results of the frequency of occurrence (number of occurrences per thread-feeding bobbin SB) of the phenomenon (severe sluffing) in which the thread Y is pulled out from the thread-feeding bobbin SB in the form of multiple rings among the above-mentioned sluffing are shown below.
-Comparative example: 2.8 times / book-Example 1: 1.0 times / book-Example 2: 0 times / book

<Peak value of unwinding tension>
The analysis result of the peak value of the tension (unwinding tension) applied to the yarn Y at the unwinding point of the yarn Y from the yarn feeding bobbin SB is shown below.
-Comparative example: 7.5 cN
Example 1: 4.7 cN
Example 2: 4.8 cN

From the results of the above analysis and experiment, according to Examples 1 and 2 in which the guide cylinders 50 and 50A provided with the high friction material layer 61 on the inner peripheral surface were adopted, the severity was higher than in the comparative example in which the conventional structure was adopted. It was confirmed that the occurrence of rafting can be suppressed and the increase in unwinding tension (peak value) can be suppressed.

Further, in the above result, according to the guide cylinder 50A (Example 2) in which the high friction material layer 61 is provided on both the first cylinder portion 51 and the second cylinder portion 52, the high friction material is provided only on the second cylinder portion 52. It was confirmed that the frequency of occurrence of severe friction can be reduced as compared with the guide cylinder 50 (Example 1) provided with the layer 61. By appropriately braking the thread Y not only in the second tubular portion 52 but also in the first tubular portion 51, the expansion of the balloon of the thread Y is suppressed more effectively, and the occurrence of severe sluffing is more effective. It is considered that it was suppressed.

Further, in the above result, according to the guide cylinder 50 (Example 1) in which the high friction material layer 61 is provided in the second cylinder portion 52 and the low friction portion (inner peripheral surface 51a) is provided in the first cylinder portion 51. It was confirmed that the peak value of the unwinding tension can be reduced slightly as compared with Example 2. As described above, in the guide cylinder 50A (Example 2), in the latter half of the unwinding where the unwinding tension peaks, the thread Y and the first by the low friction portion (inner peripheral surface 51a) provided in the first cylinder portion 51. Friction resistance with 1 cylinder portion 51 can be reduced. As a result, it is considered that the increase in unwinding tension was suppressed in Example 2 as compared with Example 1.

As another modification, the thread unwinding assisting device 20 may include the guide cylinder 50B shown in FIG. 6 instead of the guide cylinder 50 described above. The guide cylinder 50B is provided with a low friction material layer 62 (low friction portion) having a dynamic friction coefficient of 0.1 or more and less than 0.25 on the inner peripheral surface 51a of the first cylinder portion 51. It is different from 50. Specifically, in the guide cylinder 50B, the high friction material layer 61 is provided on the inner peripheral surface 52a of the second cylinder portion 52, while the low friction material layer 62 is provided on the inner peripheral surface 51a of the first cylinder portion 51. Is provided. The low friction material layer 62 can be formed, for example, by subjecting the inner peripheral surface 51a of the first tubular portion 51 to an electroless nickel PTFE composite plating treatment. According to the guide cylinder 50B, the slipperiness of the thread Y on the inner circumference of the first cylinder portion 51 is compared with that of a conventional material (for example, a salt bath soft-nitrided pickled steel sheet having a coefficient of dynamic friction of 0.25). Can be improved. As a result, the increase in the unwinding tension of the yarn Y in the latter half of the unwinding can be suppressed more effectively. Specifically, since the frictional resistance between the thread Y and the first cylinder portion 51 in the latter half of unwinding can be reduced as compared with the guide cylinder 50A described above, the increase in unwinding tension is effectively suppressed by that amount. it can.

At least a part of the above-described embodiments and various modifications may be arbitrarily combined. Further, the materials forming the guide cylinders 50, 50A, 50B, the high friction material layer 61, and the low friction material layer 62 are not limited to the above examples.

20 ... Thread unwinding assisting device, 50, 50A, 50B ... Guide cylinder, 51 ... First cylinder part, 51a ... Inner peripheral surface (low friction part), 52 ... Second cylinder part, 52a ... Inner peripheral surface, 61 ... High friction material layer (high friction part), 62 ... Low friction material layer (low friction part), L ... Central axis (reference axis), SB ... Thread feeding bobbin (bobbin), Y ... Thread.

Claims (6)

It is a thread unwinding assisting device that assists in unwinding the thread from the bobbin.
A guide tube is provided so as to cover the core tube of the bobbin.
A thread unwinding assisting device provided with a high friction portion having a coefficient of dynamic friction with respect to cotton yarn of 0.3 or more and 0.5 or less on the inner peripheral surface of the guide cylinder. The guide cylinder
A cylindrical first cylinder extending along a predetermined reference axis, and
A second end extending along the reference axis and being connected to an upstream end in the traveling direction of the thread unwound from the bobbin among both ends of the first cylinder along the reference axis. Has 2 bobbins and
The second tubular portion has a tapered shape that gradually expands from the end on the side connected to the first tubular portion toward the end opposite to the end on the side connected to the first tubular portion. Have,
The thread unwinding assisting device according to claim 1, wherein the high friction portion is provided at least on the inner peripheral surface of the second cylinder portion. The thread unwinding assisting device according to claim 2, wherein the high friction portion is provided on both the inner peripheral surface of the first cylinder portion and the inner peripheral surface of the second cylinder portion. The yarn unwinding assisting device according to claim 2, wherein a low friction portion having a coefficient of dynamic friction with respect to the cotton yarn smaller than that of the high friction portion is provided on the inner peripheral surface of the first cylinder portion. The yarn unwinding assisting device according to claim 4, wherein the dynamic friction coefficient of the low friction portion with respect to the cotton yarn is 0.1 or more and less than 0.25. The yarn unwinding assisting device according to any one of claims 1 to 5, wherein the cotton yarn is a yarn having an English cotton count of Ne30.

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