DESCRIPTION
Title of Invention
THREAD MONITORING DEVICE, THREAD MONITORING
METHOD, THREAD WINDER, AND THREAD MONITORING
5 SYSTEM
Technical Field
[0001] The present invention relates to a yarn monitoring device, a yarn
monitoring method, a yarn winder, and a yarn monitoring system.
Background Art
10 [0002] As a conventional yarn monitoring device, for example, a device
described in Patent Literature 1 is known. The yarn monitoring device
described in Patent Literature 1 calculates the deviation of a detection
signal corresponding to the thickness of traveling yarn, and checks
abnormality of a yarn surface layer on the basis of a resultant value of the
15 calculation.
Citation List
Patent Literature
[0003] [Patent Document 1] Japanese Unexamined Patent Publication
No. 2005-299037
20 Summary of Invention
Technical Problem
[0004] Examples of yarn defects to be detected by the yarn monitoring
device include unevenness in yarn thickness (variations in apparent
thickness) and excessive hairiness. Conventional yarn monitoring
25 devices have difficulty in detecting excessive hairiness while
distinguishing it from unevenness in yarn thickness.
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[0005] It is an object of an aspect of the present invention to provide a
yarn monitoring device, a yarn monitoring method, a yarn winder, and a
yarn monitoring system that can estimate hairiness quantity with high
accuracy by a simple process while detecting the presence of abnormality
5 in appearance of yarn.
Solution to Problem
[0006] As a result of diligent study to achieve the above object, the
inventors of the present invention have found that a predetermined
frequency component of a detection signal that varies with yarn thickness
10 is less likely to be affected by unevenness in thickness of a body part of
yarn. The inventors have further found that the hairiness quantity can
be estimated with high accuracy by a simple process of extracting a
predetermined frequency component from the detection signal,
calculating the standard deviation or the mean deviation of the
15 predetermined frequency component, and using this value, resulting in
having made the present invention.
[0007] A yarn monitoring device according to an aspect of the present
invention comprises: a light emitter configured to emit light toward a
traveling area where yarn travels; a light receiver disposed opposite to the
20 light emitter across the traveling area and configured to receive the light
emitted from the light emitter and partially blocked by the yarn and to
output a detection signal corresponding to the amount of the light
received; and a detection section configured to detect, based on the
detection signal, a state of the yarn traveling in the traveling area, in
25 which the detection section estimates hairiness quantity of the yarn by
extracting a predetermined frequency component from the detection
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signal and calculating a standard deviation or a mean deviation of the
extracted predetermined frequency component.
[0008] In the yarn monitoring device according to this aspect of the
present invention, the detection section estimates the hairiness quantity
of the yarn by calculating the standard de 5 viation or the mean deviation of
the predetermined frequency component. The predetermined frequency
component of the detection signal is less likely to be affected by
unevenness in thickness of a body part of the yarn. This enables the
yarn monitoring device to distinguish between unevenness in thickness
10 of the yarn and excessive hairiness of the yarn and detect them. Thus,
the yarn monitoring device can estimate the hairiness quantity with high
accuracy by a simple process of extracting the predetermined frequency
component and calculating the standard deviation or the mean deviation,
without performing complicated processing such as image processing of
15 two-dimensional images captured by a camera. Consequently, the yarn
monitoring device can estimate the hairiness quantity with high accuracy
by the simple process while detecting the presence of abnormality in the
appearance of the yarn.
[0009] In an embodiment, the detection section may determine whether
20 the hairiness quantity is excessively large, based on a result of comparison
between the standard deviation or the mean deviation and a threshold.
In this configuration, the standard deviation or the mean deviation is
compared with the threshold, and if the standard deviation or the mean
deviation exceeds the threshold, the hairiness quantity can be determined
25 to be excessively large. Thus, whether the hairiness quantity is
excessively large can be properly determined.
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[0010] In an embodiment, the detection section may compare the
standard deviation or the mean deviation with a threshold and output a
result of this comparison. In this configuration, the standard deviation
or the mean deviation is compared with the threshold, and the hairiness
quantity can be determined to be large i 5 f the standard deviation or the
mean deviation exceeds the threshold, and the hairiness quantity can be
determined to be small if not exceeding the threshold. Thus, the state of
the hairiness can be output by outputting the comparison result. This
allows an operator, for example, to check the state of the hairiness.
10 [0011] In an embodiment, the detection section may extract the
predetermined frequency component by a frequency filter. In this
configuration, the predetermined frequency component can be properly
extracted.
[0012] In an embodiment, a time corresponding to a lower frequency
15 limit of a passband in the frequency filter may be set between a time for
which the yarn travels a length of 1 cm and a time for which the yarn
travels a length of 5 cm.
[0013] In an embodiment, the detection section may detect presence of
abnormality in appearance of the yarn as the state of the yarn, based on
20 the detection signal. In this configuration, the presence of abnormality
in the appearance of the yarn can be detected.
[0014] In an embodiment, the light receiver may be a photoelectric
conversion element including one pixel.
[0015] In an embodiment, the yarn monitoring device may include a
25 holder configured to hold the light emitter and the light receiver and
having the traveling area formed therein, and at least parts, in walls of the
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holder facing the traveling area, that hold the light emitter and the light
receiver may be black in color. In this configuration, light can be
prevented from being reflected at the walls. Thus, in the yarn
monitoring device, light reflected at the walls can be prevented from
entering the light receiver. The ratio of 5 light partially blocked by the
yarn and light reflected by hairs in the total amount of received light can
be relatively increased. Thus, the yarn monitoring device can estimate
the hairiness quantity with high accuracy.
[0016] In an embodiment, the detection section may calculate a hairiness
10 count by substituting the standard deviation or the mean deviation into a
conversion formula. In this configuration, the hairiness count can be
calculated in addition to the hairiness quantity.
[0017] In an embodiment, the detection section may use the conversion
formula corresponding to a type of the yarn when calculating the hairiness
15 count. In this configuration, the hairiness count can be properly
calculated in accordance with the type of the yarn.
[0018] In an embodiment, the detection section may sample the detection
signal at every sampling interval length in the yarn. In this
configuration, a sampled value can be obtained at every sampling interval
20 length regardless of the speed of the yarn, and thus the hairiness can be
accurately detected.
[0019] In an embodiment, the sampling interval length may be 0.5 mm
or more and 5 mm or less.
[0020] In an embodiment, the detection signal may be a voltage signal
25 that varies with the state of the yarn.
[0021] A yarn monitoring method according to an aspect of the present
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invention is a yarn monitoring method to be performed by a control
section in a yarn monitoring device, in which a light emitter emits light
toward traveling yarn, and a light receiver receives light emitted from the
light emitter and partially blocked by the yarn, and outputs a detection
signal corresponding to the amount of 5 the light received to the control
section, the method including: an extraction step of extracting a
predetermined frequency component from the detection signal; and a
hairiness quantity estimation step of estimating hairiness quantity of the
yarn by calculating a standard deviation or a mean deviation of the
10 predetermined frequency component extracted at the extraction step.
[0022] In the yarn monitoring method according to this aspect of the
present invention, at the hairiness quantity estimation step, the hairiness
quantity is estimated by calculating the standard deviation or the mean
deviation of the predetermined frequency component. The
15 predetermined frequency component of the detection signal is less likely
to be affected by unevenness in thickness of a body part of the yarn.
This enables the yarn monitoring method to distinguish between
unevenness in thickness of the yarn and excessive hairiness of the yarn
and detect them. Thus, the yarn monitoring method can estimate the
20 hairiness quantity with high accuracy by a simple process of extracting
the predetermined frequency component and calculating the standard
deviation or the mean deviation, without performing complicated
processing such as image processing of two-dimensional images captured
by a camera. Consequently, the yarn monitoring method can estimate
25 the hairiness quantity with high accuracy by the simple process while
detecting the presence of abnormality in the appearance of the yarn.
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[0023] In an embodiment, at the hairiness quantity estimation step,
whether the hairiness quantity is excessively large may be determined
based on a result of comparison between the standard deviation or the
mean deviation with a threshold. In this method, the standard deviation
or the mean deviation is compared with the 5 threshold, and if the standard
deviation or the mean deviation exceeds the threshold, the hairiness
quantity can be determined to be excessively large. Thus, whether the
hairiness quantity is excessively large can be properly determined.
[0024] In an embodiment, at the hairiness quantity estimation step, the
10 standard deviation or the mean deviation may be compared with a
threshold, and a result of this comparison may be output. In this method,
the standard deviation or the mean deviation is compared with the
threshold, and the hairiness quantity can be determined to be large if the
standard deviation or the mean deviation exceeds the threshold, and the
15 hairiness quantity can be determined to be small if not exceeding the
threshold. Thus, the state of the hairiness can be output by outputting
the comparison result.
[0025] In an embodiment, at the extraction step, the predetermined
frequency component may be extracted by a frequency filter. In this
20 method, the predetermined frequency component can be properly
extracted.
[0026] In an embodiment, a time corresponding to a lower frequency
limit of a passband in the frequency filter may be set between a time for
which the yarn travels a length of 1 cm and a time for which the yarn
25 travels a length of 5 cm.
[0027] In an embodiment, at the hairiness quantity estimation step,
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presence of abnormality in appearance of the yarn may be detected as the
state of the yarn, based on the detection signal. In this method, the
presence of abnormality in the appearance of the yarn can be detected.
[0028] A yarn winder according to an aspect of the invention includes: a
yarn feeding section capable of 5 feeding yarn; a winding section
configured to wind the yarn fed by the yarn feeding section into a
package; a yarn joining section configured to perform yarn joining
operation of joining the yarn fed by the yarn feeding section and the yarn
wound by the winding section; and the above-described yarn monitoring
10 device, the yarn monitoring device being disposed between the yarn
feeding section and the winding section.
[0029] The yarn winder according to this aspect of the present invention
includes the above-described yarn monitoring device. This enables the
yarn winder to estimate the hairiness quantity with high accuracy by the
15 simple process while detecting the presence of abnormality in the
appearance of the yarn.
[0030] In an embodiment, the yarn winder may include a host device
configured to set a measurement length for calculating the standard
deviation or the mean deviation per predetermined length of the yarn and
20 output measurement length information on the measurement length to the
yarn monitoring device. The yarn monitoring device may calculate the
standard deviation or the mean deviation based on the measurement
length information output from the host device. In this configuration,
the standard deviation or the mean deviation can be calculated for each
25 measurement length regardless of the speed of the yarn, and thus the
hairiness can be accurately detected.
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[0031] A yarn monitoring system according to an aspect of the present
invention includes: the above-described yarn monitoring device; and a
host device capable of communicating data to and from the yarn
monitoring device.
[0032] The yarn monitoring system 5 according to this aspect of the
present invention includes the above-described yarn monitoring device.
This enables the yarn monitoring system to estimate the hairiness quantity
with high accuracy by the simple process while detecting the presence of
abnormality in the appearance of the yarn.
10 [0033] In an embodiment, the host device may transmit measurement
length information on the measurement length to the yarn monitoring
device for calculating the standard deviation or the mean deviation for
each predetermined length of the yarn, and the detection section may
calculate the standard deviation or the mean deviation based on the
15 measurement length information received from the host device. In this
configuration, the standard deviation or the mean deviation can be
calculated for each measurement length regardless of the speed of the
yarn, and thus the hairiness can be accurately detected.
[0034] In an embodiment, setting of the measurement length may be
20 changeable in the host device. In this configuration, the setting of the
measurement length can be changed in accordance with yarn processing
conditions such as yarn types of the yarn.
[0035] In an embodiment, the host device may transmit threshold
information on a threshold to the yarn monitoring device, and the yarn
25 monitoring device may determine whether the hairiness quantity is
excessively large, based on the standard deviation or the mean deviation
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and the threshold information received from the host device. In this
configuration, the standard deviation or the mean deviation is compared
with the threshold, and if the standard deviation or the mean deviation
exceeds the threshold, the hairiness quantity can be determined to be
excessively large. Thus, whether the hairiness 5 quantity is excessively
large can be properly determined.
[0036] In an embodiment, a hairiness count may be settable in the host
device, and the host device may convert hairiness count information on
the hairiness count into the threshold information and transmit the
10 threshold information after this conversion to the yarn monitoring device.
In this configuration, the threshold can be set in accordance with the
hairiness count.
[0037] In an embodiment, the yarn monitoring device may transmit the
standard deviation or the mean deviation to the host device, and the host
15 device may receive the standard deviation or the mean deviation
transmitted from the yarn monitoring device and calculate the hairiness
count by substituting the received standard deviation or the received
mean deviation into a conversion formula. In this configuration, the
hairiness count can be calculated in addition to the hairiness quantity.
20 [0038] In an embodiment, the host device may use the conversion
formula corresponding to a type of the yarn when calculating the hairiness
count. In this configuration, the hairiness count can be properly
calculated in accordance with the type of the yarn.
[0039] In an embodiment, the yarn monitoring system may include a
25 display section configured to display the hairiness count calculated by the
host device. In this configuration, the hairiness count is displayed on
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the display section, and thus an operator, for example, can check the
hairiness count.
[0040] In an embodiment, the detection section may acquire a yarn speed
and calculate the standard deviation or the mean deviation for each
predetermined length of the yarn, 5 and the display section may display a
trend in the hairiness count corresponding to the yarn speed. In this
configuration, the operator, for example, can check the trend in the
hairiness count.
Advantageous Effects of Invention
10 [0041] According to an aspect of the present invention, it is possible to
estimate the hairiness quantity with high accuracy by the simple process
while detecting the presence of abnormality in the appearance of the yarn.
Brief Description of Drawings
[0042] [FIG. 1] FIG. 1 is a front view of a spinning machine that is a yarn
15 winder according to an embodiment.
[FIG. 2] FIG. 2 is a side view of the spinning machine illustrated
in FIG. 1.
[FIG. 3] FIG. 3 is a diagram schematically illustrating a
configuration of a yarn monitoring device.
20 [FIG. 4] FIG. 4 is a graph illustrating a relation between
frequency and voltage as a result of analysis of detection signals by an
FFT analyzer.
[FIG. 5] FIG. 5 is a front view of an automatic winder that is a
yarn winder according to another embodiment.
25 Description of Embodiments
[0043] Preferred embodiments will now be described in detail with
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reference to the attached drawings. In the description of the drawings,
like or equivalent elements are designated by like reference signs, and
duplicate description is omitted.
[0044] As illustrated in FIG. 1, an air-jet spinning machine (yarn winder)
1 includes a plurality of spinning units (5 winding units) 2, a yarn joining
cart 3, a doffing cart (not illustrated), a first end frame 4, and a second
end frame 5. The spinning units 2 are aligned in a row. Each spinning
unit 2 forms yarn Y and winds it into a package P. When yarn Y has
been cut or the yarn Y has broken for some reason in a certain spinning
10 unit 2, the yarn joining cart 3 performs yarn joining operation in the
spinning unit 2. When a package P has been fully wound on a certain
spinning unit 2, the doffing cart doffs the package P, and supplies a new
bobbin B to the spinning unit 2.
[0045] The first end frame 4 accommodates, for example, a collection
15 device configured to collect fiber waste, yarn waste, and the like
generated in the spinning unit 2. The second end frame 5
accommodates, for example, an air supply unit configured to adjust air
pressure of compressed air (air) to be supplied to the air-jet spinning
machine 1 and supply the air to the respective sections of the air-jet
20 spinning machine 1 and a drive motor configured to supply power to the
respective sections in the spinning units 2. The second end frame 5
includes a machine control device (detection section) 5a, a display screen
(display section) 5b, and input keys 5c. The machine control device 5a
centrally manages and controls the respective sections of the air-jet
25 spinning machine 1. The display screen 5b can display, for example,
information on settings and/or the status of the spinning units 2. An
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operator can make the settings of the spinning units 2 by performing
appropriate operations with the input keys 5c.
[0046] Each spinning unit 2 includes, in the order from the upstream side
in a direction in which yarn Y travels, a drafting device 6, an air-jet
spinning device (yarn feeding section) 7, 5 a yarn monitoring device 8, a
tension sensor 9, a yarn storage device 11, a waxing device 12, and a
winding device (winding section) 13. A unit controller 10 is provided
for every predetermined number of spinning units 2, and controls
operations of the spinning units 2. The unit controller 10 is configured
10 with one or more computer devices, for example. The unit controller 10
includes a central processing unit (CPU), which is a processor, and a
random access memory (RAM) or a read only memory (ROM), which is
a recording medium. The unit controller 10 executes various controls
by loading programs, for example, on hardware such as the CPU and the
15 RAM.
[0047] The drafting device 6 drafts a sliver (fiber band) S. The air-jet
spinning device 7 forms yarn Y by twisting a fiber band F drafted by the
drafting device 6 using swirling airflow.
[0048] The yarn monitoring device 8 monitors yarn Y traveling between
20 the air-jet spinning device 7 and the yarn storage device 11 to detect the
presence of a yarn defect. Examples of the yarn defect to be detected
include excessive hairiness. The examples of the yarn defect may
further include at least one of a nep, a slub, a yarn color defect, different
yarn count abnormality, weak yarn, yarn physical property change, and
25 the like. When having detected a yarn defect, the yarn monitoring
device 8 transmits a yarn defect detection signal to the unit controller 10.
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The yarn monitoring device 8 and the machine control device 5a can
communicate data via the unit controller 10. The yarn monitoring
device 8 and the machine control device 5a constitute a yarn monitoring
system.
[0049] The tension sensor 9 measures 5 the tension of traveling yarn Y
between the air-jet spinning device 7 and the yarn storage device 11, and
transmits a tension measurement signal to the unit controller 10. When
the unit controller 10 has determined that abnormality has occurred based
on detection results of the yarn monitoring device 8 and/or the tension
10 sensor 9, the yarn Y is cut in the spinning unit 2.
[0050] The yarn storage device 11 eliminates slack in yarn Y between the
air-jet spinning device 7 and the winding device 13. The waxing device
12 applies wax to yarn Y between the yarn storage device 11 and the
winding device 13.
15 [0051] The winding device 13 winds yarn Y onto a bobbin B to form a
package P. The winding device 13 includes a cradle arm 14, a winding
drum 15, and a traverse mechanism 16. The cradle arm 14 rotatably
supports the bobbin B.
[0052] As illustrated in FIG. 2, the yarn joining cart 3 travels to a
20 spinning unit 2 in which yarn Y has been cut, and performs yarn joining
operation in this spinning unit 2. The yarn joining cart 3 includes a yarn
joining device (yarn joining section) 3a. The yarn joining device 3a
performs yarn joining operation of joining yarn Y fed by the air-jet
spinning device 7 and yarn Y wound by the winding device 13. The
25 yarn joining device 3a is a splicer using compressed air, or a knotter
configured to mechanically join the yarns Y.
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[0053] The following describes the yarn monitoring device 8 in detail.
As illustrated in FIG. 3, the yarn monitoring device 8 includes a holder
20, a light emitter 22, a light receiver 24, a control section (detection
section) 26, and a casing 28. FIG. 3 illustrates a configuration of the
yarn monitoring device 8 when viewed 5 from a direction in which yarn Y
travels.
[0054] The holder 20 holds the light emitter 22 and the light receiver 24.
The casing 28 accommodates the holder 20 and the control section 26.
The holder 20 has a cubic shape, for example. In the holder 20, a
10 traveling area R is formed. The traveling area R is a space extending
along the traveling direction of the yarn Y and being open to the front side
of the machine. In other words, the traveling area R is a path through
which the traveling yarn Y passes, and is formed in the shape of a groove
extending from upstream to downstream in the traveling direction of the
15 yarn Y and being open to the front side of the machine. The traveling
area R is defined by walls 20a, 20b of the holder 20. The walls 20a, 20b
are black. The light emitter 22 and the light receiver 24 are preferably
disposed at the same position in the traveling direction of the yarn Y.
More specifically, at least a wall surface of the wall 20a at a position
20 (range), in the traveling direction of the yarn Y, where the light emitter 22
and the light receiver 24 are held is preferably black in color. Herein,
the "black" is not limited to strictly pitch black. Because the purpose is
to clearly distinguish it from the color of yarn Y (generally white), it only
needs to be a dark color that achieves this purpose and may have some
25 saturation.
[0055] The light emitter 22 is disposed so as to emit light toward the yarn
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Y traveling in the traveling area R of the holder 20. The light emitter 22
is disposed on the side of one wall 20a of the pair of walls 20a, 20b that
are opposed to each other. For example, a light emitting diode (LED)
can be used as the light emitter 22. The luminescent color of the light
emitter 22 is not limited to a particular 5 one, and may be blue, yellow, or
green, for example. The light emitter 22 may also emit infrared light.
The light emitter 22 is driven by a drive circuit (not illustrated).
[0056] The light receiver 24 receives light emitted from the light emitter
22. The light receiver 24 is disposed on the side of the other wall 20b
10 of the pair of walls 20a, 20b that are opposed to each other. The light
receiver 24 is disposed opposite to the light emitter 22. In other words,
the light receiver 24 is disposed, in the holder 20, opposite to the light
emitter 22 with the traveling area R therebetween. The light receiver 24
is a photoelectric conversion element including one pixel. For example,
15 a photodiode can be used as the light receiver 24. The light receiver 24
outputs, to the control section 26, a detection signal (analog signal:
waveform data) corresponding to the amount of received light that has
been partially blocked by the yarn Y. The detection signal is a voltage
signal that varies with the thickness (state) of yarn Y.
20 [0057] The control section 26 controls the yarn monitoring device 8.
The control section 26 includes a central processing unit (CPU) and a
random access memory (RAM) or a read only memory (ROM), which is
a recording medium. The control section 26 includes an amplifier, a
low-pass filter, and a sample-and-hold circuit (all not illustrated). The
25 control section 26 processes the detection signal output from the light
receiver 24 by using the amplifier, the low-pass filter, and the sampleFP20-
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and-hold circuit.
[0058] The control section 26 detects the presence of a yarn defect on the
basis of the detection signal of the light receiver 24. In the present
embodiment, a method for detecting excessive hairiness (excessively
large hairiness quantity) as a yarn defect 5 (yarn monitoring method) will
be described in detail. The control section 26 extracts a predetermined
high-frequency component from the detection signal and detects the
hairiness of yarn Y on the basis of the deviation of the high-frequency
component. The predetermined high-frequency component means a
10 frequency component higher than a predetermined frequency or a
frequency component in a range higher than the predetermined frequency.
The predetermined high-frequency component is set in accordance with
the type of yarn Y and the speed of yarn Y, for example.
[0059] The control section 26 digitally processes the detection signal
15 output from the light receiver 24. The control section 26 performs
sampling processing on the analog signal that is the detection signal and
converts it into a digital signal. The control section 26 samples the
analog signal at a predetermined sampling frequency. The
predetermined sampling frequency is set by Equation (1) given below.
20 In the present embodiment, the control section 26 samples the analog
signal at every sampling interval length in yarn Y. The sampling
interval length is 0.5 mm or more and 5 mm or less. The control section
26 changes the sampling frequency in accordance with changes in yarn
speed, and performs the sampling at every fixed length of yarn Y
25 (sampling interval length). In the present embodiment, this fixed length
of yarn Y is 1 mm, for example. In other words, the control section 26
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performs the sampling at every length of 1 mm of yarn Y, regardless of
the yarn speed. The control section 26 may sample the analog signal at
regular time intervals regardless of whether the yarn speed changes.
[Equation 1]
sampling frequency = 5 yarn speed/sampling interval length
[0060] The control section 26 analyzes digital signals thus digitally
processed. The control section 26 extracts a predetermined frequency
component from each digital signal (extraction step). The
predetermined frequency component is a frequency band that is not
10 affected by unevenness in thickness of a body portion of yarn Y
(variations in apparent thickness). The lower frequency limit of the
predetermined frequency component is set based on a period. The
period is a time determined based on the traveling speed and the length
of yarn Y. The time corresponding to the lower frequency limit of the
15 predetermined frequency component is set between a time for which the
yarn Y travels a length of 1 cm and a time for which the yarn Y travels a
length of 5 cm. In the present embodiment, the control section 26
extracts, as the predetermined frequency component, a frequency band at
or higher than a lower frequency limit corresponding to a time for which
20 the yarn Y travels a length of 2 cm. The predetermined frequency
component is a frequency equal to or higher than 250 Hz, for example.
For example, the time for which the yarn Y travels a length of 2 cm is 4
ms when the traveling speed of the yarn Y is 5 m/s. In this case, the
predetermined frequency component is 250 Hz or higher.
25 [0061] The control section 26 extracts the predetermined frequency
component by processing the detection signal with a high-pass filter
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(frequency filter). The control section 26 extracts the predetermined
frequency component by using the high-pass filter with a passband the
lower frequency limit of which is 250 Hz. As described above, the
cutoff frequency of the high-pass filter varies depending on the yarn
speed. Thus, sampling at 5 a fixed period requires a high-pass filter
corresponding to the period. However, when sampling is performed at
every fixed length of yarn Y as in the present embodiment, the filter
coefficient can be set constant.
[0062] The control section 26 calculates the standard deviation of
10 extracted high-frequency component signals (hairiness quantity
estimation step). The standard deviation is calculated based on a
measurement length (e.g., 1 m or more and 20 m or less). The control
section 26 calculates the standard deviation for each measurement length
of yarn Y (e.g., 10 m). The measurement length is preset in the machine
15 control device (host device) 5a. The machine control device 5a can
change the setting of the measurement length. The machine control
device 5a outputs (transmits) measurement length information on the
measurement length to the yarn monitoring device 8. When having
received the measurement length information, the control section 26
20 calculates the standard deviation based on the measurement length
information. The control section 26 may calculate the mean deviation
instead of the standard deviation. The mean deviation is also calculated
for each measurement length of yarn Y.
[0063] When having calculated the standard deviation, the control
25 section 26 compares the value of the standard deviation with a threshold
to detect an excessively hairy part. In other words, the control section
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26 compares the value of the standard deviation with the threshold to
determine whether the hairiness quantity is excessively large. The
threshold is a preset value and is stored in a recording medium. The
threshold is a value that serves as a criterion for detecting hairiness
(excessively large hairiness quantity), 5 and can be changed as needed.
The threshold is set based on threshold information transmitted from the
machine control device 5a. The machine control device 5a can set the
hairiness count of yarn Y. The machine control device 5a converts
hairiness count information on the set hairiness count into threshold
10 information, and transmits the threshold information to the yarn
monitoring device 8 via the unit controller 10. The yarn monitoring
device 8 detects an excessively hairy part, using the threshold based on
the received threshold information.
[0064] If the value of the standard deviation exceeds the threshold, the
15 control section 26 outputs a control signal (yarn defect signal) to the unit
controller 10. In the present embodiment, if the number of times the
threshold was exceeded is consecutively equal to or greater than a
predetermined number of times, the control section 26 outputs the control
signal to the unit controller 10. When having received the control signal,
20 the unit controller 10 causes each spinning unit 2 to perform
predetermined processes of issuing an alarm, stopping feeding yarn, and
cutting yarn, for example.
[0065] The control section 26 outputs the standard deviation to the unit
controller 10. When having received the standard deviation, the unit
25 controller 10 outputs it to the machine control device 5a.
[0066] The machine control device 5a calculates the hairiness count (the
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hairiness count per predetermined length). The machine control device
5a calculates a first hairiness count and/or a second hairiness count. The
first hairiness count is the number of hairs in a first length range. The
first length range is 1 mm or more and less than 3 mm. The second
hairiness count is the number of hairs 5 in a second length range that is
longer than the first length range. The second length range is 3 mm or
more. The length referred to in the first length range and the second
length range is the length of a hair protruding radially from the body part
of yarn Y. The machine control device 5a calculates the hairiness count
10 by substituting the value of the standard deviation to a predetermined
conversion formula. The machine control device 5a uses conversion
formulas corresponding to the type of yarn Y when calculating the
hairiness count. The conversion formulas depending on the type of yarn
Y are stored in the recording medium. The conversion formulas are
15 preset individually for the first hairiness count and the second hairiness
count as follows.
First hairiness count = Standard deviation × a1 + b1
Second hairiness count = Standard deviation × a2 + b2
[0067] In the above formulas, a1 and a2 are coefficients (slopes). In the
20 present embodiment, for example, a1 is greater than a2 (a1 > a2). b1
and b2 are intercepts. In the present embodiment, for example, b1 is
greater than b2 (b1 > b2). The machine control device 5a can
simultaneously calculate the first hairiness count and the second hairiness
count by substituting the standard deviation to each of the above
25 conversion formulas. Each conversion formula is set such that the value
is converted into a value corresponding to the measurement value of
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hairiness measured with a typical existing hairiness measuring instrument
(G567 manufactured by Zweigle).
[0068] As described above, in the yarn monitoring device 8 of the air-jet
spinning machine 1 according to the present embodiment, the control
section 26 extracts the predetermined 5 frequency component from the
detection signal, and detects hairiness of yarn Y based on the standard
deviation of the predetermined frequency component. The machine
control device 5a calculates the hairiness count by substituting the
standard deviation received from the control section 26 into each
10 conversion formula.
[0069] FIG. 4 is a graph illustrating results of analysis of detection
signals by the FFT analyzer and a relation between frequency and signal
strength. In FIG. 4, the horizontal axis represents frequency [Hz] and
the vertical axis represents voltage [V] as signal strength. The plot
15 indicated by the solid line in FIG. 4 represents the result of analysis of
yarn Y spun at the standard spinning speed. The plot indicated by the
dashed line in FIG. 4 represents the result of analysis of yarn Y spun at a
faster speed than the standard spinning speed. The yarn Y spun at a
speed faster than the standard spinning speed has more hairiness than the
20 yarn Y spun at the standard spinning speed. In the example in FIG. 4, a
significant difference in signal intensity can be observed between the
different spinning speeds in the range of about 250 Hz or more and about
2500 Hz or less.
[0070] As illustrated in FIG. 4, the two types of yarns the hairiness
25 quantities of which are different exhibit differences in the analysis results
in a predetermined frequency band (about 250 Hz or more). Thus, the
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inventors of the present invention presumed that there is a high
correlation between the detection signal and the hairiness quantity in the
predetermined frequency band, verified the correlation, and consequently
could confirm that results indicating the high correlation could be
obtained. It is presumed that 5 the predetermined frequency component
of the detection signal is less likely to be affected by unevenness in
thickness of the body part of yarn Y. Thus, by detecting hairiness based
on the standard deviation of the frequency component of the lower
frequency limit corresponding to the frequency band at or higher than a
10 predetermined value, e.g., the time to travel a length of 2 cm, the yarn
monitoring device 8 can distinguish between unevenness in thickness of
the yarn Y and hairiness (excessively hairy part) of the yarn Y and detect
them. Thus, the yarn monitoring device 8 can estimate the hairiness
quantity with high accuracy by a simple process of extracting the
15 predetermined frequency component and calculating the standard
deviation, without performing complicated processing such as image
processing of two-dimensional images captured by a camera.
Consequently, the yarn monitoring device 8 can estimate the hairiness
quantity with high accuracy by the simple process while detecting the
20 presence of abnormality in the appearance of the yarn Y. Herein, the
abnormality in the appearance is, for example, abnormality in thickness
(unacceptable unevenness in thickness) of the yarn Y, and does not
include abnormality in hairiness quantity (excessive hairiness, etc.).
[0071] In the air-jet spinning machine 1 according to the present
25 embodiment, the control section 26 of the yarn monitoring device 8
determines whether the hairiness quantity is excessively large based on a
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result of comparison between the standard deviation and the threshold.
In this configuration, the standard deviation is compared with the
threshold, and if the standard deviation exceeds the threshold, the
hairiness quantity can be determined to be excessively large. Thus,
whether the hairiness quantity is 5 excessively large can be properly
determined.
[0072] In the air-jet spinning machine 1, the control section 26 of the
yarn monitoring device 8 extracts the predetermined frequency
component by processing the detection signal with the high-pass filter.
10 In this configuration, the predetermined frequency component can be
properly extracted.
[0073] In the air-jet spinning machine 1, the yarn monitoring device 8
includes the holder 20 configured to hold the light emitter 22 and the light
receiver 24 and having the traveling area R formed therein. In the
15 holder 20, the walls 20a, 20b that hold the light emitter 22 and the light
receiver 24 are black in color. In this configuration, light can be
prevented from being reflected at the walls 20a, 20b. Thus, in the yarn
monitoring device 8, light reflected at the walls 20a, 20b can be prevented
from entering the light receiver 24. The ratio of light partially blocked
20 by the yarn Y and light reflected by hairs in the total amount of received
light can be relatively increased. Thus, in the yarn monitoring device 8,
the accuracy of hairiness detection can be further improved.
[0074] In the air-jet spinning machine 1 according to the present
embodiment, the machine control device 5a uses the conversion formula
25 corresponding to the type of yarn Y, and outputs the value of a hairiness
count calculated by substituting the standard deviation into the
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conversion formula. In this configuration, in addition to detecting
hairiness, the hairiness count can be displayed. The yarn monitoring
device 8 can estimate the hairiness quantity while winding the yarn Y.
Because the air-jet spinning machine 1 uses the conversion formula to
calculate the value of the hairiness 5 count in the machine control device
5a, the conversion formula can be set and managed, for example,
centrally in the machine control device 5a. This eliminates the need to
set the conversion formula in each of the yarn monitoring devices 8 or to
output data relating to the conversion formula to the yarn monitoring
10 devices 8. Thus, the conversion formula can be easily changed, for
example.
[0075] In the air-jet spinning machine 1 according to the present
embodiment, the control section 26 of the yarn monitoring device 8
samples the detection signal at every sampling interval length in yarn Y.
15 The sampling interval length is 1 mm. In this configuration, a sampled
value for each fixed yarn length can be obtained regardless of the yarn Y
speed, and thus the hairiness can be accurately detected. Furthermore,
the filter processing does not have to be changed in accordance with the
yarn speed, and thus extraction of the predetermined frequency
20 component can be simplified.
[0076] The air-jet spinning machine 1 according to the present
embodiment includes the machine control device 5a configured to set the
measurement length for calculating the standard deviation per
predetermined length of yarn Y and output measurement length
25 information on the measurement length to the yarn monitoring device 8.
The yarn monitoring device 8 calculates the standard deviation based on
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the measurement length information output from the machine control
device 5a. In this configuration, the standard deviation for each
measurement length can be calculated regardless of the speed of yarn Y,
and thus the hairiness can be accurately detected. In the air-jet spinning
machine 1, the measurement length is 5 set in the machine control device
5a, and the measurement length information is output from the machine
control device 5a to each of the yarn monitoring devices 8 (spinning units
2), and thus the measurement length can be set and managed, for example,
collectively in a single machine control device 5a. Thus, the
10 measurement length can be easily changed, for example.
[0077] The control section 26 of the yarn monitoring device 8 according
to the present embodiment performs sampling processing on the analog
signal that is a detection signal and converts it into a digital signal. The
control section 26 samples the analog signal at a predetermined sampling
15 frequency. The control section 26 performs filter processing (extraction
of the predetermined range frequency) on the digital signal. In this
configuration, the frequency range to be extracted (cutoff frequency) can
be easily changed. For example, the frequency range to be extracted can
be changed in accordance with various yarn processing conditions such
20 as yarn types of yarn Y.
[0078] Although the embodiment of the present invention has been
described above, the present invention is not necessarily limited to the
embodiment described above, and various modifications may be made
without departing from the gist thereof.
25 [0079] In the above embodiment, an example of a configuration has been
described in which the control section 26 extracts the predetermined
FP20-1222-00IN-MRT
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frequency component by processing the detection signal with the highpass
filter. However, the method of extracting the predetermined
frequency component is not limited to this. For example, a bandpass
filter (frequency filter) may be used to extract the predetermined
5 frequency component.
[0080] In the above embodiment, an example of a configuration has been
described in which the machine control device 5a calculates the hairiness
count. However, the yarn monitoring device 8 may calculate the
hairiness count, or the unit controller 10 may calculate the hairiness count.
10 By sharing the processing among the respective devices, the processing
load at each device and/or the communication load between the
respective devices can be reduced.
[0081] In the above embodiment, an example of a configuration has been
described in which the machine control device 5a calculates the first
15 hairiness count and the second hairiness count. However, the machine
control device 5a may calculate one type of hairiness count or three or
more types of hairiness counts. For example, the machine control
device 5a may calculate the hairiness count in the length ranges of "less
than 2 mm, less than 3 mm, and 3 mm or more". The conversion
20 formulas can be used to calculate various patterns of hairiness counts by
changing the coefficients and the intercepts.
[0082] In the above embodiment, an example of a configuration has been
described in which the control section 26 outputs the standard deviation
to the unit controller 10. However, the control section 26 may compare
25 the standard deviation or the mean deviation with the threshold and output
a result of the comparison. In this configuration, the standard deviation
FP20-1222-00IN-MRT
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or the mean deviation is compared with the threshold, and the hairiness
quantity can be determined to be large if the standard deviation or the
mean deviation exceeds the threshold, and the hairiness quantity can be
determined to be small if not exceeding the threshold. When using two
or more thresholds, the control section 26 c 5 an classify the state of
hairiness into three or more levels. The control section 26 can report
(display) the state of hairiness by outputting this comparison result
(classification result). In this configuration, the state of hairiness of yarn
Y can be reported in real time while the yarn is traveling (during yarn
10 winding). This allows an operator, for example, to check the state of the
hairiness.
[0083] In the above embodiment, when the standard deviation calculated
by the control section 26 satisfies a predetermined condition, the unit
controller 10 causes the corresponding spinning unit 2 to perform the
15 predetermined processes of issuing an alarm, stopping feeding yarn, and
cutting yarn, for example. However, the air-jet spinning machine 1 does
not have to do such predetermined processes. For example, the standard
deviation calculated by the control section 26 may be converted into a
hairiness count, and the hairiness count may be simply displayed. The
20 standard deviation corresponds to the hairiness quantity. Based on the
calculated standard deviation, the air-jet spinning machine 1 can take
various actions (display, count, alarm, etc.) relating to the hairiness, and
only needs to take at least one of these actions.
[0084] In the above embodiment, each spinning unit 2 preferably
25 includes means for detecting (acquiring) the yarn speed. Furthermore,
the corresponding yarn monitoring device 8 preferably includes means
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for detecting the yarn speed. In this case, the control section 26 of the
yarn monitoring device 8 can perform sampling corresponding to the
sampling interval length based on the detected yarn speed. Herein, the
spinning unit 2 may include means for detecting the yarn speed separately
from the yarn monitoring device 5 8. The control section 26 may also
perform sampling corresponding to the sampling interval length based on
the yarn speed (the yarn speed that is a target winding speed input by the
operator) set in a setting device such as the machine control device 5a.
[0085] In the above embodiment, the hairiness count can be displayed.
10 However, not only the hairiness count, but also a trend in the hairiness
count (or the hairiness quantity) corresponding to the yarn speed may be
displayed, for example. In other words, changes in the hairiness count
(or the hairiness quantity) may be displayed in response to changes in the
yarn speed.
15 [0086] In the spinning unit 2, the yarn storage device 11 has a function
of pulling out yarn Y from the air-jet spinning device 7. However, the
yarn Y may be pulled out from the air-jet spinning device 7 by a delivery
roller and a nip roller. When the yarn Y is pulled out from the air-jet
spinning device 7 by a delivery roller and a nip roller, instead of the yarn
20 storage device 11, a slack tube or a mechanical compensator, for example,
configured to absorb slack of the yarn Y using suction airflow may be
provided.
[0087] In the air-jet spinning machine 1, the respective devices are
disposed such that yarn Y fed from the upper side in the height direction
25 is wound at the lower side. However, the respective devices may be
disposed such that yarn fed from the lower side is wound at the upper side.
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[0088] In the air-jet spinning machine 1, at least one of bottom rollers of
each drafting device 6 and the corresponding traverse mechanism 16 are
driven by power from the second end frame 5 (i.e., driven centrally for a
plurality of spinning units 2). However, the respective sections (e.g., the
drafting device, the air-jet spinning de 5 vice, the winding device) of each
spinning unit 2 may be driven independently in each spinning unit 2.
[0089] The tension sensor 9 may be disposed upstream of the yarn
monitoring device 8 in the traveling direction of yarn Y. The unit
controller 10 may be provided to each spinning unit 2. In each spinning
10 unit 2, the waxing device 12 and the tension sensor 9 may be omitted.
[0090] In FIG. 1, the air-jet spinning machine 1 is illustrated such that
cheese-shaped packages P are wound. However, cone-shaped packages
P may also be wound. In the case of cone-shaped packages, slack of
yarn is generated by traversing the yarn, but this slack can be absorbed
15 by the yarn storage device 11. The materials and shapes of the
respective components are not limited to those described above, and
various types of materials and shapes may be used.
[0091] In the above embodiment, an example of a configuration has been
described in which the yarn monitoring device 8 is provided to the air-jet
20 spinning machine 1. However, the yarn monitoring devices may be
provided to an automatic winder or a ring spinning machine, for example.
[0092] As an example, a configuration in which a yarn monitoring device
is provided to an automatic winder will be described. As illustrated in
FIG. 5, an automatic winder (yarn winder) 30 includes a plurality of
25 winding units 32, a doffing cart 34, a first end frame 36, and a second end
frame 38.
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[0093] The second end frame 5 includes a machine control device
(detection section) 40a, a display screen (display section) 40b, and input
keys 40c. The machine control device 40a centrally manages and
controls the respective sections of the automatic winder 30.
[0094] The winding units 32 are a 5 ligned in a row. Each winding unit
32 winds yarn Y1 unwound from a yarn feeding bobbin SB while
traversing it, thereby forming a package P1.
[0095] The winding unit 32 includes a yarn feeding section 42, a yarnunwinding
assisting device 44, a tension applying device 46, a yarn
10 joining device 48, a yarn monitoring device 50, and a winding device
(winding section) 52.
[0096] The yarn feeding section 42 holds a yarn feeding bobbin SB,
which has been conveyed by a bobbin conveying system (not illustrated),
at a predetermined position. The yarn-unwinding assisting device 44
15 controls a balloon formed by yarn Y1 unwound from the yarn feeding
bobbin SB to an appropriate size, thereby assisting smooth unwinding of
the yarn Y1. The tension applying device 46 applies a predetermined
tension to the traveling yarn Y1. When the yarn monitoring device 50
has detected a yarn defect and cuts the yarn, or when the yarn being
20 unwound from the yarn feeding bobbin SB breaks, for example, the yarn
joining device 48 joins lower yarn from the yarn feeding bobbin SB and
upper yarn from the package P1. The winding device 52 winds the yarn
Y1 onto the package P1 while traversing it.
[0097] The yarn monitoring device 50 has the same configuration as that
25 of the yarn monitoring device 8 of the air-jet spinning machine 1. More
specifically, the yarn monitoring device 50 includes constituents
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corresponding to the holder 20, the light emitter 22, the light receiver 24,
the control section 26, and the casing 28 of the yarn monitoring device 8.
[0098] The yarn monitoring device 50 extracts a predetermined
frequency component from a detection signal, and detects the hairiness
of yarn Y based on the standard de 5 viation (mean deviation) of the
predetermined frequency component. The yarn monitoring device 50
calculates the standard deviation in the extracted high-frequency
component signal. The standard deviation is calculated based on a
measurement length (e.g., 1 m or more and 20 m or less). The yarn
10 monitoring device 50 calculates the standard deviation per predetermined
length (e.g., per 10 m) of yarn Y based on the measurement length. The
measurement length is preset in the machine control device (host device)
40a. The machine control device 40a outputs (transmits) measurement
length information on the measurement length to the yarn monitoring
15 device 50. When having received the measurement length information,
the yarn monitoring device 50 calculates the standard deviation based on
the measurement length information. The yarn monitoring device 50
may calculate the mean deviation instead of the standard deviation. The
mean deviation is also calculated per predetermined length of yarn Y.
20 [0099] When having calculated the standard deviation (mean deviation),
the yarn monitoring device 50 compares the value of the standard
deviation (mean deviation) with a threshold to detect an excessively hairy
part. If the value of the standard deviation (mean deviation) exceeds the
threshold, the yarn monitoring device 50 outputs a control signal (yarn
25 defect signal) to the unit controller 10. When having received the
control signal, the unit controller 10 causes each winding unit 32 to
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perform predetermined processes of stopping an alarm and cutting yarn,
for example. The yarn monitoring device 50 also outputs the standard
deviation to the unit controller 10. When having received the standard
deviation, the unit controller 10 outputs it to the machine control device
40a. The machine control device 40a calculates 5 the hairiness count (the
hairiness count per predetermined length). The machine control device
40a calculates the first hairiness count and/or the second hairiness count.
The machine control device 40a calculates the hairiness count by
substituting the value of the standard deviation to the corresponding
10 predetermined conversion formula. The conversion formula is set in
accordance with the type of yarn Y. In the case of ring yarn, for example,
examples of the type of yarn Y include carded yarn and combed yarn.
[0100] As described above, in the automatic winder 30, the yarn
monitoring device 50 estimates the hairiness quantity of yarn Y1 based
15 on the standard deviation of the high frequency component. The
predetermined high-frequency component of the detection signal is less
likely to be affected by unevenness in thickness of the body portion of
yarn Y1. This enables the yarn monitoring device 50 to distinguish
between unevenness in thickness of the yarn Y1 and excessive hairiness
20 of the yarn Y1 and detect them. Thus, in the yarn monitoring device 50,
the accuracy of hairiness detection can be improved.
[0101] The automatic winder 30 includes a machine control device 40a
configured to set a measurement length for calculating the standard
deviation per predetermined length of yarn Y and output measurement
25 length information on the measurement length to the yarn monitoring
device 50. The yarn monitoring device 50 calculates the standard
FP20-1222-00IN-MRT
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deviation based on the measurement length information output from the
machine control device 40a. In this configuration, the standard
deviation for each measurement length can be calculated regardless of the
speed of yarn Y, and thus the hairiness can be accurately detected.
[0102] In the automatic winder 30, 5 after winding of yarn Y1 from a new
yarn feeding bobbin SB has been started, when the yarn monitoring
device 50 has detected an excessively hairy part at the time the yarn Y1
has been wound for the measurement length, the yarn feeding bobbin SB
is considered to be a defective bobbin having much hairiness, the winding
10 of the yarn Y1 is stopped, and the yarn feeding bobbin SB is ejected from
the winding unit 32. Thus, when the measurement length is set to be
shorter, a defective bobbin can be detected earlier, whereby unnecessary
winding of the yarn Y1 can be avoided. On the other hand, when the
measurement length is too short, the value of the standard deviation is not
15 stable. In view of this, the measurement length is set to be 1 m or more
and 20 m or less, for example.
[0103] In the above embodiment, each winding unit 32 preferably
includes means for detecting the yarn speed. Furthermore, the
corresponding yarn monitoring device 50 preferably includes means for
20 detecting the yarn speed. In this case, the control section of the yarn
monitoring device 50 can perform sampling corresponding to the
sampling interval length based on the detected yarn speed. Herein, the
winding unit 32 may include means for detecting the yarn speed
separately from the yarn monitoring device 50. The control section may
25 also perform sampling corresponding to the sampling interval length
based on the yarn speed (the yarn speed that is a target winding speed
FP20-1222-00IN-MRT
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input by the operator) set in a setting device such as the machine control
device 40a.
[0104] In the above embodiment, the hairiness count can be displayed.
However, not only the hairiness count, but also a trend in the hairiness
count (or the hairiness quantity) 5 corresponding to the yarn speed may be
displayed, for example. In other words, changes in the hairiness count
(or the hairiness quantity) may be displayed in response to changes in the
yarn speed. Alternatively, for example, a trend in the hairiness count (or
the hairiness quantity) may be displayed for each yarn feeding bobbin SB.
10 In other words, changes in the hairiness count (or the hairiness quantity)
from the start of unwinding to the completion thereof may be displayed
for each yarn feeding bobbin SB.
[0105] In the above embodiments, an example of a configuration has
been described in which the host devices are the machine control devices
15 5a, 40a. However, the host devices are not limited to the machine
control devices 5a, 40a, and may be a device provided separately from
the machine control devices 5a, 40a.
[0106] In addition to the above embodiments, when the standard
deviation or the mean deviation is calculated, another factor may be
20 combined for the calculation. As the other factor, for example,
skewness or kurtosis can be used. By combining the other factor in the
calculation of the standard deviation or the mean deviation, the accuracy
of the hairiness quantity estimation can be increased.
Reference Signs List
25 [0107] 1 ... air-jet spinning machine (yarn winder)
3a ... yarn joining device (yarn joining section)
FP20-1222-00IN-MRT
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5a ... machine control device (detection section)
5b ... display screen (display section)
7 ... air-jet spinning device (yarn feeding section)
8, 50 ... yarn monitoring device
13 ... winding de 5 vice (winding section)
20 ... holder
20a, 20b ... wall
22 ... light emitter
24 ... light receiver
10 26 ... control section (detection section)
30 ... automatic winder (yarn winder)
40a ... machine control device (detection section)
40b ... display screen (display section)
42 ... yarn feeding section
15 48 ... yarn joining device (yarn joining section)
52 ... winding device (winding section)
R ... traveling area
Y, Y1 ... yarn

CLAIMS
1. A yarn monitoring device comprising:
a light emitter configured to emit light toward a traveling area
where yarn travels;
a light receiver disposed opposite to t 5 he light emitter across the
traveling area and configured to receive the light emitted from the light
emitter and partially blocked by the yarn and to output a detection signal
corresponding to the amount of the light received; and
a detection section configured to detect, based on the detection
10 signal, a state of the yarn traveling in the traveling area, wherein
the detection section estimates hairiness quantity of the yarn by
extracting a predetermined frequency component from the detection
signal and calculating a standard deviation or a mean deviation of the
extracted predetermined frequency component.
15 2. The yarn monitoring device according to claim 1, wherein the
detection section determines whether the hairiness quantity is excessively
large, based on a result of comparison between the standard deviation or
the mean deviation with a threshold.
3. The yarn monitoring device according to claim 1 or 2, wherein
20 the detection section compares the standard deviation or the mean
deviation with a threshold and outputs a result of this comparison.
4. The yarn monitoring device according to any one of claims 1 to
3, wherein the detection section extracts the predetermined frequency
component by a frequency filter.
25 5. The yarn monitoring device according to claim 4, wherein a time
corresponding to a lower frequency limit of a passband in the frequency
FP20-1222-00IN-MRT
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filter is set between a time for which the yarn travels a length of 1 cm and
a time for which the yarn travels a length of 5 cm.
6. The yarn monitoring device according to any one of claims 1 to
5, wherein the detection section detects presence of abnormality in
appearance of the yarn as the state 5 of the yarn, based on the detection
signal.
7. The yarn monitoring device according to any one of claims 1 to
6, wherein the light receiver is a photoelectric conversion element
including one pixel.
10 8. The yarn monitoring device according to any one of claims 1 to
7, comprising a holder configured to hold the light emitter and the light
receiver and having the traveling area formed therein, wherein
at least parts, in walls of the holder facing the traveling area, that
hold the light emitter and the light receiver is black in color.
15 9. The yarn monitoring device according to any one of claims 1 to
8, wherein the detection section calculates a hairiness count by
substituting the standard deviation or the mean deviation into a
conversion formula.
10. The yarn monitoring device according to claim 9, wherein the
20 detection section uses the conversion formula corresponding to a type of
the yarn when calculating the hairiness count.
11. The yarn monitoring device according to any one of claims 1 to
10, wherein the detection section samples the detection signal at every
sampling interval length in the yarn.
25 12. The yarn monitoring device according to claim 11, wherein the
sampling interval length is 0.5 mm or more and 5 mm or less.
FP20-1222-00IN-MRT
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13. The yarn monitoring device according to any one of claims 1 to
12, wherein the detection signal is a voltage signal that varies with the
state of the yarn.
14. A yarn monitoring method to be performed by a control section
in a yarn monitoring device, in which a light 5 emitter emits light toward
traveling yarn, and a light receiver receives light emitted from the light
emitter and partially blocked by the yarn, and outputs a detection signal
corresponding to the amount of the light received to the control section,
the method comprising:
10 an extraction step of extracting a predetermined frequency
component from the detection signal; and
a hairiness quantity estimation step of estimating hairiness
quantity of the yarn by calculating a standard deviation or a mean
deviation of the predetermined frequency component extracted at the
15 extraction step.
15. The yarn monitoring method according to claim 14, wherein at
the hairiness quantity estimation step, whether the hairiness quantity is
excessively large is determined based on a result of comparison between
the standard deviation or the mean deviation with a threshold.
20 16. The yarn monitoring method according to claim 14 or 15, wherein
at the hairiness quantity estimation step, the standard deviation or the
mean deviation is compared with a threshold, and a result of this
comparison is output.
17. The yarn monitoring method according to any one of claims 14
25 to 16, wherein at the extraction step, the predetermined frequency
component is extracted by a frequency filter.
FP20-1222-00IN-MRT
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18. The yarn monitoring method according to claim 17, wherein a
time corresponding to a lower frequency limit of a passband in the
frequency filter is set between a time for which the yarn travels a length
of 1 cm and a time for which the yarn travels a length of 5 cm.
19. The yarn monitoring m 5 ethod according to any one of claims 14
to 18, wherein at the hairiness quantity estimation step, presence of
abnormality in appearance of the yarn is detected as the state of the yarn,
based on the detection signal.
20. A yarn winder comprising:
10 a yarn feeding section capable of feeding yarn;
a winding section configured to wind the yarn fed by the yarn
feeding section into a package;
a yarn joining section configured to perform yarn joining
operation of joining the yarn fed by the yarn feeding section and the yarn
15 wound by the winding section; and
the yarn monitoring device according to any one of claims 1 to
13, wherein
the yarn monitoring device is disposed between the yarn feeding
section and the winding section.
20 21. The yarn winder according to claim 20, comprising: a host device
configured to set a measurement length for calculating the standard
deviation or the mean deviation per predetermined length of the yarn and
output measurement length information on the measurement length to the
yarn monitoring device, wherein
25 the yarn monitoring device calculates the standard deviation or
the mean deviation based on the measurement length information output
FP20-1222-00IN-MRT
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from the host device.
22. A yarn monitoring system comprising:
the yarn monitoring device according to any one of claims 1 to
13; and
a host device capable of communicating 5 data to and from the yarn
monitoring device.
23. The yarn monitoring system according to claim 22, wherein
the host device transmits measurement length information on the
measurement length to the yarn monitoring device for calculating the
10 standard deviation or the mean deviation for each predetermined length
of the yarn, and
the detection section calculates the standard deviation or the mean
deviation based on the measurement length information received from the
host device.
15 24. The yarn monitoring system according to claim 23, wherein
setting of the measurement length is changeable in the host device.
25. The yarn monitoring system according to any one of claims 22 to
24, wherein the host device transmits threshold information on a
threshold to the yarn monitoring device, and
20 the yarn monitoring device determines whether the hairiness
quantity is excessively large, based on the standard deviation or the mean
deviation and the threshold information received from the host device.
26. The yarn monitoring system according to claim 25, wherein
a hairiness count is settable in the host device, and
25 the host device converts hairiness count information on the
hairiness count into the threshold information and transmits the threshold
FP20-1222-00IN-MRT
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information after this conversion to the yarn monitoring device.
27. The yarn monitoring system according to claim 26, wherein
the yarn monitoring device transmits the standard deviation or the
mean deviation to the host device, and
the host device receives 5 the standard deviation or the mean
deviation transmitted from the yarn monitoring device, and calculates the
hairiness count by substituting the received standard deviation or the
received mean deviation into a conversion formula.
28. The yarn monitoring system according to claim 27, wherein the
10 host device uses the conversion formula corresponding to a type of the
yarn when calculating the hairiness count.
29. The yarn monitoring system according to claim 27 or 28,
comprising a display section configured to display the hairiness count
calculated by the host device.
15 30. The yarn monitoring system according to claim 29, wherein
the detection section acquires a yarn speed and calculates the
standard deviation or the mean deviation for each predetermined length
of the yarn, and
the display section displays a trend in the hairiness count
20 corresponding to the yarn speed.