JPH08209527A - Device for detecting abnormality of linear material - Google Patents

Abstract

PURPOSE: To provide a device for detecting abnormality of a linear material, capable of accurately detecting abnormality of the linear material including filament in high detection sensitivity regardless of the position of an abnormal part. CONSTITUTION: Yarn as a linear material traveling in the horizontal direction at high speed is irradiated with an elliptic beam-shaped parallel laser beam 3b vertically having its major axis made from a laser beam 3a from a semiconductor laser 2 by an optical lens system 4. A reflecting mirror 5 is arranged at the opposite side to the laser beam irradiating face for the yarn. Normal diffracted light reflecting from the reflecting mirror 5 by the yarn is reflected. Abnormal diffracted light by a fluff 13 is reflected. The normal diffracted light, the abnormal diffracted light and abnormal diffracted light of reflected light reflected from the normal diffracted light by the fluff 13 are received by normal diffracted light receptor parts 8a and 8b and abnormal diffracted light receptor parts 9a and 9b of a light sensor 6 having through holes for transmitting the laser beams 3b, respectively. Detecting voltages of the normal diffracted light receptor parts 8a and 8b and the abnormal diffracted light receptor parts 9a and 9b are supplied to an abnormality detecting circuit 11 to detect abnormality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an abnormality in a linear body formed by twisting a large number of thin wires and detecting an abnormal portion of a linear body running at a predetermined speed, for example, a fluff of a thread by a laser beam. Regarding

[0002]

2. Description of the Prior Art As a conventional linear body abnormality detecting device,
For example, the one described in JP-A-5-163666 is known. This conventional example is a fluff detector that detects the fluff of a filament formed by twisting a large number of fine wires, and irradiates the filament with a laser light source that irradiates a laser beam from the side of the filament. And an optical sensor having a light receiving surface which is arranged on the diffracting surface of the laser beam and which spreads in the irradiation area of the diffracted light excluding the 0th-order diffracted light and the diffracted light which spreads in a direction substantially orthogonal to the extending direction of the filamentous body. A fluff detector, which detects fluff of a filamentous body that runs at high speed with high sensitivity.

[0003]

However, in the above-described conventional linear body abnormality detecting apparatus, the side surface of the filamentous material is irradiated with laser light from the laser light source, and the filamentous material is applied to the laser light source. An optical sensor is placed on the opposite side of the body so as to detect the diffracted light of the filament, so that the fluff of the filament is directly irradiated with the laser light. When it is extended or when it is projected and extended in the direction toward the laser light source, it can be detected with relatively high sensitivity, but the fluff is projected and extended toward the optical sensor on the back side of the laser light irradiation surface. In this case, the sensitivity is reduced to about 1/10 of that in other cases, and accurate fluff detection cannot be performed, and the output voltage depending on the presence or absence of fluff of the optical sensor, which indicates the fluff detection sensitivity. When there is a difference or fluff There is an unsolved problem that it is not possible to a value obtained by subtracting the output voltage during fluff without the output voltage a large value.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and accurately detects an abnormality of a linear body including a filamentous body with high detection sensitivity regardless of the position of the abnormal place. It is an object of the present invention to provide a linear body abnormality detecting device capable of performing the above.

[0005]

In order to achieve the above object, an apparatus for detecting an abnormality of a linear body according to a first aspect of the present invention is a linear body formed by twisting a large number of fine wires and traveling at a predetermined speed. In a linear body abnormality detecting device for detecting an abnormal part of the linear body by a laser beam, a laser light source for irradiating the linear body with parallel laser light from a direction intersecting the traveling direction, and the laser light source and the linear body. A reflecting means for reflecting the laser light, which is disposed on the diffractive surface facing each other with the laser light source interposed therebetween, and a through hole for transmitting the laser light, which is disposed between the laser light source and the linear body, It is characterized by including a light receiving means for receiving diffracted light.

According to a second aspect of the present invention, there is provided the linear object abnormality detecting device according to the first aspect of the present invention, wherein the light receiving means extends in the direction perpendicular to the traveling direction of the linear body from the through hole. A normal diffracted light receiving part that receives the diffracted light in a normal state that is formed in a band shape considering the shake of the body and a diffracted light by an abnormal part that is symmetrically arranged with the normal diffracted light receiving part interposed It is characterized in that it is configured with an abnormal diffracted light receiving section.

Further, in the apparatus for detecting an abnormality of a linear body according to a third aspect, in the invention of the first or second aspect, the linear body is a thread formed by twisting a thin wire, and the abnormal portion is a fluff. It is characterized by that. Furthermore, the linear body abnormality detecting apparatus according to claim 4 is characterized in that the laser beam with which the linear body is irradiated is selected as an elliptical beam having a major axis in the deflection direction of the linear body. There is.

[0008]

According to the first aspect of the present invention, the laser light emitted from the laser light source is irradiated onto the linear body traveling at a predetermined speed from the side surface thereof, and the irradiated light is abnormal such as fluff protruding and extending from the linear body. The diffracted light diffracted by the reflection section is reflected by the reflection mirror that is the reflection means and is received by the abnormal diffraction light receiving section of the light receiving section, and the diffracted light by the linear body of the laser light is reflected by the reflection mirror. Is again irradiated to the side opposite to the laser light irradiation surface of the linear body, so that diffracted light that is anomalously diffracted by this reflected light is obtained and is directly received by the light receiving means. Therefore, the amount of light received by the light receiving means is the sum of the amount of abnormally diffracted light due to the irradiation of the laser light and the amount of abnormally diffracted light due to the reflected light reflected by the reflecting mirror. It is possible to double the output difference depending on the presence / absence of the above-mentioned case as compared with the above-mentioned conventional example, and it is possible to detect the abnormality with high sensitivity regardless of the location of the abnormal portion.

In the invention of claim 2, the light receiving means is
The linear body is composed of the band-shaped normal diffracted light receiving section in consideration of the shake of the linear body and the abnormal diffracted light receiving section symmetrically arranged with the normal diffracted light receiving section sandwiched therebetween. Even when the traveling route of the device swings in the direction orthogonal to the irradiation direction of the laser light, the normal diffracted light receiving unit can accurately receive the normal diffracted light, and it is possible to detect the presence or absence of disconnection of the linear body. In addition, it is possible to surely prevent the abnormal diffracted light receiving section from erroneously detecting the normal diffracted light due to the shake of the linear body.

According to the third aspect of the present invention, since the filamentous body is the linear body and the fluff is the abnormal portion, the fluff can be accurately detected, and when the cloth is woven with this filament, the fluff position is detected. It is possible to detect the disconnection due to the stress concentration in advance. In the invention of claim 4, since the laser beam applied to the linear body is selected as an elliptical beam having a major axis in the deflection direction of the linear body, excellent diffracted light can be obtained even when the linear body swings. Can be received by the light receiving means via the reflection mirror.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, in which 1 is a thread as a linear object to be inspected, and a large number of synthetic fiber fine wires are twisted together to have a maximum diameter. Is 1
It is formed into a synthetic yarn of about 00 μm and runs horizontally at a high speed of about 4000 to 6000 m / min by a predetermined running device. In the spinning device, although not shown, the yarn 1 runs in parallel with about 10 to 30 yarns at a pitch of 50 to 100 mm.

A semiconductor laser 2 as a laser light source is disposed at a front position orthogonal to the running direction of the yarn 1 with its output optical axis aligned with the center of the yarn 1. The semiconductor laser 2 is selected such that the wavelength of the laser light is 630 to 900 nm and the output is 3 to 5 mW. The laser beam 3a emitted from the semiconductor laser 2 is converted into an elliptical parallel laser beam 3b having a beam diameter of 1 mm in the short axis and 3 mm in the long axis by the optical lens system 4 such as an aspherical lens, and the long axis is in the vertical direction. The yarn 1 is irradiated in this manner.

On the other hand, a reflecting mirror 5 as a flat reflecting means having a diameter of, for example, 20 mm is provided on the opposite side of the semiconductor laser 2 with respect to the thread 1, that is, on the diffractive surface located behind the thread 1. . Here, the distance between the yarn 1 and the reflection mirror 5 is preferably as short as possible so that more diffracted light of the laser light on the front side of the yarn 1 can be reflected, and it is preferable to select about 2 mm, for example.

Further, an optical sensor 6 as a light receiving means for receiving the diffracted light of the yarn 1 is disposed between the optical lens system 4 and the yarn 1 at a position separated by 15 mm from the yarn 1, for example. As shown in FIG. 2, the optical sensor 6 has, for example, a side of 40
A square substrate 6a having a diameter of 5 mm is formed with a through hole 7 having a diameter of, for example, 5 mm for transmitting the laser beam 3b at the center thereof, and a light receiving surface facing the reflection mirror 5 has a vertical line passing through the center of the through hole 7. A normal diffracted light receiving portion 8 configured by, for example, a photodiode array that receives normal diffracted light in a strip shape having a width of, for example, 3 mm in consideration of the vertical deflection of the yarn 1 along the LV.
a, 8b are formed, and these normal diffracted light receiving portions 8a, 8b are formed.
It has a configuration in which the extraordinary diffracted light receiving portions 9a and 9b which are symmetrically configured to receive the semicircular extraordinary diffracted light with the b in between are similarly formed. Here, the normal diffracted light receiving portions 8a and 8b and the abnormal diffracted light receiving portion 9
On the surface facing a and 9b, gaps 10a and 10 of about 1 mm are formed.
b is formed. Each light receiving portion 8a, 8b and 9a, 9
From b, detection voltages V _N and V _A corresponding to the amount of received diffracted light are output.

Each of these light receiving portions 8a, 8b and 9a, 9b
The detection voltage output from is input to the abnormality detection circuit 11, and this abnormality detection circuit 11 detects whether or not the yarn 1 is in an abnormal state in which there is a fluff due to a broken thin line. In this abnormality detection circuit 11, the yarn 1 from the normal diffracted light receiving portions 8a and 8b is
The presence or absence of disconnection of the yarn 1 itself is determined by the detection voltage based on the 0th-order diffracted light, and based on the detection voltage based on the abnormal diffracted light due to the fluff caused by the fine line cutting generated in the yarn 1 from the abnormal diffracted light receiving portions 9a and 9b The detection voltage difference is calculated by subtracting the detection voltage when the yarn 1 is normal without fluff from the detection voltage at that time, and the presence or absence of fluff is determined based on this, and the normal signal S _N and the abnormal signal that are the determination results are calculated. S _A is supplied to the alarm device 12.

In the alarm device 12, when the normal signal S _N is supplied, the normal lamp 12N for indicating a normal state is turned on, and when the abnormal signal S _A is supplied, an abnormal state of fluff generation is displayed. For example, the red abnormality lamp 12A is turned on and the buzzer 12B emits an alarm sound. Next, the operation of the above embodiment will be described.

Now, assuming that the yarn 1 running at high speed in the horizontal direction is in a normal state in which no fluff is generated due to the breakage of fine lines, in this normal state, the light is emitted from the semiconductor laser 2 and the optical lens system 4 is used. By irradiating the front surface of the yarn 1 with the laser light 3b that has become parallel light, as shown in FIG. 3, diffraction that extends in the vertical direction orthogonal to the traveling direction of the yarn 1 on the reflecting surface of the reflection mirror 5 is performed. Produces light. This diffracted light is
The 0th-order diffracted light L ₀ having the largest amount of light generated at the position directly behind the yarn 1, and the yarn diameter d, the wavelength of the laser light 3 λ, and the constant A, which are sequentially generated on the upper and lower sides of the _0th- order diffracted light L ₀ , respectively. , The first-order diffracted light L ₁ and the second-order diffracted light L ₂ have peaks for each center interval S represented by the following formula (1). The light intensity of the diffracted lights L _1, L _2, ... Of the _{1st and} higher orders is much lower than that of the _0th-order diffracted light L ₀ .

S = Aλ / d (1) Then, the diffracted light on the reflecting surface of the reflecting mirror 5 is reflected and received by the normal diffracted light receiving portions 8a and 8b of the optical sensor 7. The 0th-order diffracted light reflected by the reflection mirror 5 irradiates the back side of the yarn 1, and the 0th-order diffracted light by this reflected light is similarly superimposed on the front-side diffracted light by the normal diffracted light receiving portions 8a and 8b. The normal diffracted light receiving portions 8a and 8b receive the normal diffracted light pattern P _N shown by the broken line in FIG.

Therefore, the normal diffracted light receiving portion 8
From a and 8b, the detection voltage V _N of a relatively large value is output, which is the sum of the external incident light quantity of the atmosphere in which the detection device is arranged and the light quantity of the 0th-order diffracted light by the yarn 1. On the other hand, since there is no abnormal portion such as fluff in the yarn 1, diffracted light is not generated by the abnormal portion, so that the abnormal diffracted light receiving portions 9a and 9b of the optical sensor 6 are incident on the outside in the atmosphere in which the detection device is arranged. A relatively small extraordinary diffracted light detection voltage V _A corresponding to only the amount of light is output.

Since the detection voltages V _N and V _A are supplied to the abnormality detection circuit 11, the detection circuit 11
Since the detected voltage V _N is a large value, it is determined that the yarn 1 is not broken, and the detected voltage V _A is small, and the detected voltage V _A set in advance from this detected voltage V _A is normal. _{Since the} detected voltage difference, which is a value obtained by subtracting _AS , becomes substantially zero, it can be determined that the yarn 1 does not have fluff due to a broken thin line, and a logical value "1" indicating that the yarn 1 is normal. The normal signal S _{N of} “” is supplied to the alarm device 12 to turn on the normal lamp 12N.

When fluffs 13 projecting upward from the normal state of the yarn 1 as shown in FIG. 1 are generated, the yarn 1 is emitted from the semiconductor laser 2 and is paralleled by the optical lens system 4. When the fluff 13 is irradiated with the laser light 3b that has become light, an abnormal diffracted light 14 is generated by the fluff 13 shown by the broken line in FIG. 1, and the abnormal diffracted light 14 is reflected by the reflection mirror 5 and is reflected by the optical sensor 7. Extraordinary diffracted light receiving parts 9a, 9
The light is received as an abnormal diffracted light pattern P _A indicated by a broken line in FIG. On the other hand, the normal diffracted light diffracted by the yarn 1 is the 0th-order diffracted light L having the highest light intensity directly behind the yarn 1 as described above.
_{Since 0} is reflected by the reflection mirror 5 and is applied to the back side of the thread 1, the reflected light also causes extraordinary diffracted light 15 in the fluff 13, and the extraordinary diffracted light 15 is directly transmitted to the extraordinary diffracted light receiver 9a9b. The extraordinary diffracted light 14 is superimposed and received.

Therefore, a relatively large abnormal diffracted light detection voltage V _A is output from the abnormal diffracted light receiving sections 9a and 9b to the abnormality detection circuit 11, so that the abnormal diffracted light detection voltage input by the detection circuit 11 is detected. detecting the voltage difference becomes a value obtained by subtracting the abnormality diffracted light detected voltage V _aS in the normal from V _a becomes a large value. This detected voltage difference is, for example, the wavelength λ of the laser light 3 is
Table 1 below at 80 nm and laser output of 3 mW
As shown in FIG. 2, it becomes 2200 mV, and it is possible to obtain a detection voltage difference more than twice as large as the output voltage difference 970 mV when the same fluff is detected by the same detection device as the above-mentioned conventional example. The generated fluff 13 can be detected with high sensitivity. In this way, when the detected voltage difference becomes a large value, the abnormality detection circuit 11 sends the abnormality signal S _A to the alarm device 1.
2 is output to the alarm device 12, the alarm lamp 12A is turned on, and the buzzer 12B is activated to emit an alarm sound.

Similarly, when the fluff 13 is formed on the back side of the yarn 1, the 0 due to the yarn 1 reflected by the reflection mirror 5 is more than the abnormal diffracted light due to the laser light 3a emitted to the front side.
The abnormal diffracted light generated by directly irradiating the fluff 13 with the next diffracted light L ₀ has a higher light intensity, and this is received by the abnormal diffracted light receiving portions 9a and 9b of the optical sensor 6, so that the abnormal condition in this case occurs. The diffracted light detection voltage V _{A is} also lower than that of the above fluff, but is output as a sufficiently large value. Therefore, the detection voltage difference calculated by the abnormality detection circuit 11 is, for example, 1400 mV as shown in Table 1, which is 10 times or more the detection voltage difference of 120 mV of the same conventional example, and the fluff generated on the back side with high sensitivity. 13 can be accurately detected, and in this case also, the alarm device 12 issues an alarm.

Further, even when the fluff 13 is generated on the lower side and the front side, a large abnormal diffracted light detection voltage V _A is output, which causes the abnormality detection circuit 11 to output 2100 mV and 1800 mV, respectively, as shown in Table 1. Detection voltage difference of 980 m
It is possible to improve the sensitivity both inside and outside of V and 950 mV, and in these cases, the alarm device 12 also issues an alarm.

In Table 1, the case where the fluff 13 is on the upper side is 0 degree, and the output voltage difference of the present invention and the output voltage difference of the conventional example when the fluff 13 is rotated clockwise by 90 degrees. The results of comparison are shown.

[0026]

[Table 1]

Further, since the yarn 1 travels at a high speed by a predetermined traveling device, the yarn 1 travels while swinging vertically with respect to the laser beam 3b, but as described above, the laser beam 3b is perpendicular to the long axis. Since it is formed into an elliptical beam having a horizontal axis and a short axis, the laser beam 3b can be reliably irradiated onto the yarn 1 even when the yarn 1 is swung up and down. It is possible to reliably prevent the yarn 1 from coming off and being erroneously determined to be broken.

As described above, according to the above-mentioned embodiment, the front side of the yarn 1 is irradiated with the laser beam 3a and the back side thereof is irradiated with the laser beam 3a.
Since the 0th-order diffracted light having the highest light intensity among the diffracted light from the yarn 1 is reflected by the reflection mirror 5 and is irradiated, the back surface side opposite to the surface side irradiated with the laser light 3a of the thread 1 Even if the fluff 13 is formed on the fluff, the fluff can be accurately detected with high sensitivity, and furthermore, the fluff is directly irradiated with the laser light 3a and the laser light 3a
Since the reflected light of the 0th-order diffracted light L ₀ reflected by the yarn 1 is reflected by the reflection mirror 5, diffracted light is generated for both the direct light and the reflected light of the 0th-order diffracted light, and both are superposed.
Since the light is received by the extraordinary diffracted light receiving portions 9a and 9b of the optical sensor 6, the output voltage of these extraordinary diffracted light receiving portions 9a and 9b can be doubled, and the fluff detection sensitivity can be improved.

In the above embodiment, the case where the abnormal portion is the fluff 13 of the yarn 1 has been described, but the present invention is not limited to this and occurs in a single yarn such as a monofilament as shown in FIG. Even in the case where the diameter of the so-called bump is an abnormal portion 20 that partially bulges 1.2 times or more, the abnormal diffracted light diffracted by the abnormal portion 20 has a different direction from the diffracted light at the normal time. Therefore, the abnormal diffracted light receiving portions 9a and 9b of the optical sensor 6 can receive light, and the same abnormality detection as described above can be performed.

Further, in the above embodiment, the case where the thread 1 is applied as the linear body has been described, but the present invention is not limited to this, and an electric wire in which thin copper wires are twisted together or a thin wire such as an optical fiber or an optical fiber is twisted. The present invention can be applied to any linear body formed by the above. Further, in the above embodiment, the case where the laser beam 3b for irradiating the yarn 1 is formed into an elliptical beam has been described. However, the present invention is not limited to this, and a circular beam may be used. When the deflection in the direction is small, the beam diameter can be made close to the diameter of the yarn 1.

Furthermore, in the above embodiment, the thread 1
Has been described as traveling in the horizontal direction. However, the present invention is not limited to this, and even in the case of traveling in the vertical direction or an arbitrary direction, an abnormality can be detected with the same configuration as above. Furthermore, in the above embodiment, the case where the semiconductor laser is applied as the laser light source has been described, but the present invention is not limited to this, and it goes without saying that various other gas lasers and solid-state lasers can be applied. .

Further, in the above embodiment, the case where the reflection mirror 5 has a plane shape has been described, but the present invention is not limited to this, and the central portion for reflecting the 0th-order diffracted light has a plane shape and the periphery thereof is required. You may make it form a concave shape as a whole as an arc surface shape of curvature. Furthermore, in the above embodiment, when the abnormality detection circuit 11 detects an abnormality,
Although the case where the alarm device 12 issues the alarm has been described, the invention is not limited to this, and the abnormal signal S _A may be supplied to the manufacturing device of the yarn 1 or the loom to automatically stop them.

[0033]

As described above, according to the first aspect of the invention, the laser light emitted from the laser light source is applied to the linear body traveling at a predetermined speed from the side surface thereof, and the irradiation light is emitted from the line. The diffracted light diffracted by the abnormal portion such as fluff protruding from the filamentous body is reflected by the reflecting means and received by the abnormal diffracted light receiving portion of the light receiving means, and the diffracted light by the linear body of the laser light is reflected by the reflecting means. The reflected light reflected by is again irradiated to the side opposite to the laser light irradiation surface of the linear body, so that the diffracted light that is diffracted by the abnormal portion is obtained even by this reflected light, and this is directly received by the light receiving means. With this configuration, the abnormal diffracted light receiving section of the light receiving means receives the abnormal diffracted light due to the laser light and the abnormal diffracted light due to the reflected light of the diffracted light diffracted by the linear light This abnormal diffracted light receiving section It is possible to increase the light output amount, the effect is obtained that the laser beam-irradiated surface of the linear body can be accurately abnormality detection with high sensitivity even when there is an abnormality of the fluff such as on the other side.

According to the second aspect of the invention, the light receiving means is arranged symmetrically with the band-shaped normal diffracted light receiving section and the normal diffracted light receiving section sandwiched in consideration of the shake of the linear body. Since it is composed of the abnormal diffracted light receiving section, even if the traveling path of the linear body swings in the direction orthogonal to the irradiation direction of the laser light, the normal diffracted light receiving section accurately outputs the normal diffracted light. It can receive light, can detect the presence or absence of disconnection of the linear body, and can reliably prevent erroneous detection of normal diffracted light due to shake of the linear body in the abnormal diffracted light receiving unit. The effect is obtained.

Further, according to the invention of claim 3, since the filamentous body is the linear body and the abnormal portion is the fluff, the fluff can be accurately detected, and when the cloth is woven with this filamentous body. Moreover, it is possible to obtain the effect that cutting due to stress concentration at the fluff position can be detected in advance. Still further, according to the invention of claim 4, since the laser beam with which the linear body is irradiated is selected as an elliptical beam having a major axis in the swing direction of the linear body, even when the linear body swings, It is possible to reliably irradiate the linear body with laser light, and to obtain good diffracted light that can be received by the light receiving means via the reflection mirror.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a front view showing an example of an optical sensor.

FIG. 3 is an explanatory diagram showing a light intensity of diffracted light on a reflection mirror.

[Explanation of symbols]

 1 Thread 2 Semiconductor Laser 3a, 3b Laser Light 4 Optical Lens System 5 Reflecting Mirror 6 Optical Sensor 7 Through Holes 8a, 8b Normal Diffraction Light Receiving Section 9a, 9b Abnormal Diffraction Light Receiving Section 11 Abnormality Detection Circuit 12 Alarm Device 13 Fluff

[Procedure amendment]

[Submission date] February 8, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a front view showing an example of an optical sensor.

FIG. 3 is an explanatory diagram showing a light intensity of diffracted light on a reflection mirror.

FIG. 4 is an explanatory diagram showing another example of the abnormal portion of the yarn.

[Explanation of Codes] 1 thread 2 semiconductor laser 3a, 3b laser light 4 optical lens system 5 reflection mirror 6 optical sensor 7 through hole 8a, 8b normal diffracted light receiver 9a, 9b abnormal diffracted light receiver 11 abnormal detection circuit 12 alarm Device 13 Fluff 20 Abnormal part

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Added

[Correction content]

[Figure 4]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D03J 1/00 Z G01N 21/39 21/89 E

Claims (4)

[Claims] 1. A linear body abnormality detection device for detecting an abnormal portion of a linear body, which is formed by twisting a large number of thin wires and runs at a predetermined speed, with a laser beam. A laser light source for irradiating parallel laser light from a direction intersecting with the laser light source, a reflecting means for reflecting the laser light arranged on a diffraction surface facing the laser light source with the linear body interposed therebetween, the laser light source and the linear shape A branch line detecting device for a linear body, comprising: a light receiving means having a through hole disposed between the bodies for transmitting a laser beam and receiving diffracted light from the linear body. 2. The normal diffraction that receives the diffracted light in a normal state, which is formed in a band shape in consideration of the shake of the linear body in a direction orthogonal to the traveling direction of the linear body, from the through hole. 2. The light receiving section and the abnormal diffracted light receiving section for receiving the diffracted light by the abnormal section symmetrically arranged with the normal diffracted light receiving section sandwiched therebetween. Branch detection device for linear objects. 3. The abnormality detecting device for a linear body according to claim 1, wherein the linear body is a thread formed by twisting a fine wire, and the abnormal portion is a fluff. 4. The laser beam with which the linear body is irradiated is selected as an elliptical beam whose major axis is the deflection direction of the linear body. Abnormality detection device for linear objects.