JP2018197736A - Defect detection device for conveyor belt - Google Patents

Abstract

To more surely detect the defect of a conveyor belt.SOLUTION: A defect detection device for a conveyor belt 10 includes a conveyor device 1 which includes an endless conveyor belt 2, a driving device 8 which operates the conveyor belt 2 along a longitudinal direction, an imaging apparatus 11 which acquires the three-dimensional image data of the surface of the conveyor belt 2, while operating the conveyor belt 2, defect detection means 13 which detects the defect existing on the surface of the conveyor belt 2 on the basis of the three-dimensional image data, and alarm means 14 which issues an alarm, when the defect detection means 13 detects the defect. A plurality of imaging apparatuses 11 are arranged along the width direction of the conveyor belt 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a conveyor belt defect detection device for detecting various defects such as scratches and cracks on the surface of a conveyor belt.

  A conveyor apparatus using an endless conveyor belt is configured such that an endless conveyor belt is wound between a driving pulley and a driven pulley, and the conveyor belt is moved by rotation of the driving pulley, and the conveyor The transported material on the belt is transported.

  Since various conveyed objects, pulleys, and rollers come into contact with the conveyor belt, various defects such as scratches and cracks may occur on the surface. If such a defect is left unattended, it gradually increases and the conveyor belt becomes unusable. Therefore, it is necessary to stop the movement of the conveyor device at an early stage and repair the defective part. In general, the repair of the defect is performed by bonding, filling, and integrating the repair material made of resin, rubber, or the like to the defective portion of the conveyor belt.

  Whether or not a defect has occurred in the conveyor belt is generally confirmed by visually checking the surface of the conveyor belt after stopping the movement of the conveyor device. However, it takes a lot of labor to visually confirm the presence or absence of these defects, and there is a problem that the belt conveyor device must be stopped during the confirmation period.

  For this reason, for example, as shown in Patent Document 1, a conductive material is embedded in the cover rubber of the conveyor belt, and a defect such as a crack in the conveyor belt based on a change in impedance of an eddy current coil provided close to the cover rubber. There is also a technology that automatically detects.

  Further, for example, as shown in Patent Documents 2 and 3, a technique for automatically detecting a defect in a conveyor belt by a non-contact sensor using ultrasonic waves, radar waves, or the like as a medium is also disclosed.

JP-A-7-291425 JP 58-6811 A JP-A-10-29717

  In the technique described in Patent Document 1, there is a problem that a conductive material must be embedded in the conveyor belt in advance. For this reason, there is a problem that the conveyor belt is expensive and cannot be applied to a conveyor belt not provided with a conductive material.

  In the technique described in Patent Document 2, the transmitting unit and the receiving unit of the ultrasonic device are opposed to each other in the belt width direction on the upper surface side of the return side belt on which the conveyed product is not placed among the endless conveyor belt. The defect of the conveyor belt is detected by detecting the presence or absence of a conveyed product that has fallen on the return side belt through the defect penetrating the feeding side belt in the thickness direction. However, this technique has a problem that defects that do not penetrate the conveyor belt in the thickness direction are overlooked.

  In the technique described in Patent Document 3, the direction of the millimeter wave electromagnetic wave transmitting portion is changed along the belt width direction with respect to the surface of the endless conveyor belt, so that the millimeter wave electromagnetic wave is moved along the belt width direction. Sequentially radiate and scan. Conveyor belt defects are detected by continuously measuring the round trip time from the transmission of the millimeter wave electromagnetic wave until the reflected wave is received, and detecting the local change in the round trip time.

  However, with this technique, the reflected wave may not be received well depending on the irradiation direction of the millimeter wave electromagnetic wave to the defective part. In such a case, there is a problem that the defect cannot be accurately determined. In addition, the movable part that changes the direction of the transmitting part of the millimeter wave electromagnetic wave needs to be placed close to the conveyor belt. Detection error may occur.

  Therefore, an object of the present invention is to more reliably detect a conveyor belt defect.

  In order to solve the above-described problems, the present invention provides a conveyor device having an endless conveyor belt, a drive device for operating the conveyor belt along a longitudinal direction, and three-dimensional image data of the surface of the conveyor belt. An imaging device that is acquired while operating the conveyor belt, a defect detection unit that detects a defect present on the surface of the conveyor belt based on the three-dimensional image data, and an alarm when the defect detection unit detects a defect The image pickup device employs a conveyor belt defect detection device arranged in a plurality along the width direction of the conveyor belt.

  Here, the imaging device may employ a configuration that is arranged toward the lower surface of the return side belt of the conveyor belt. As another configuration, the imaging device may employ a configuration that is arranged toward the lower surface of the feeding belt of the conveyor belt. As yet another configuration, the imaging device includes both a device arranged toward the lower surface of the return belt of the conveyor belt and a device arranged toward the lower surface of the feed belt of the conveyor belt. The provided structure can be employed.

  As yet another configuration, a configuration in which the conveyor belt is disposed toward the upper surface of the return side belt of the conveyor belt can be employed. As yet another configuration, a combination of these can be employed.

  In each of these aspects, a scraper device that scrapes off deposits on the surface of the conveyor belt is provided on a reversing portion of the conveyor belt from the feeding side belt to the returning side belt or the returning side belt, and the imaging device is provided on the scraper device. The structure arrange | positioned downstream can be employ | adopted.

  Furthermore, in each of these embodiments, a configuration including a temperature acquisition device that acquires temperature data of the surface of the conveyor belt while operating the conveyor belt can be employed together with the imaging device. In the case of providing this temperature acquisition device, the defect detection means detects defects present on the surface of the conveyor belt by referring to the temperature data together with the three-dimensional image data.

  Further, the alarm means may employ a configuration having a function of stopping the operation of the conveyor belt.

  Further, the defect detection device throws out a color ball that can rupture and attach a color to the collided portion in order to be a target of subsequent warning and repair for the defect detected by the defect detection means. It can be set as the structure provided with the marker throwing-out apparatus.

Furthermore, the defect detection device comprises:
One point of the conveyor belt is provided with a position designation mechanism that serves as a reference point (B),
A reference point specifying means for checking a reference time point (t0) when the position specifying mechanism has passed the observation point (O) relative to the conveyor belt;
A distance (| L |) from an imaging point (S) imaged by the imaging device to an observation point (O) checked by the reference point specifying means;
The moving speed (v) of the conveyor belt;
A time (T) from the reference time point (t0) to a time point (t1) at which the defect detection means detects a defect (E);
From the above, it is possible to adopt a configuration including a reference point detection function for calculating a distance (| D |) from the reference point (B) of the defect (E) in the conveyor belt.

  As a combination of the position specifying mechanism and the reference point specifying means, a combination of a reflection sheet and an optical sensor that detects reflection of light by the reflection sheet, or a non-contact passive short-range wireless communication tag and its short distance A combination with an IC tag reader capable of reading a wireless communication tag can be employed.

  Furthermore, the defect detection apparatus having the reference point detection function determines the distance of the defect from the reference point, and then positions the defect in a work area for repairing the defect, and the conveyor It can be set as the structure provided with the stop function for repair which stops a belt.

  In the present invention, when determining a defect on the surface of the conveyor belt, the imaging apparatus is adapted to the three-dimensional image data covering the surface area, so that the defect generated in the conveyor belt is detected more reliably. be able to.

  Further, since a plurality of the imaging devices are provided along the belt width direction, a three-dimensional stereoscopic image of the surface of the conveyor belt can be acquired without providing a movable part. For this reason, the malfunction of a device and generation | occurrence | production of a detection error can be prevented more reliably. That is, the defect which generate | occur | produced in the conveyor belt can be detected more reliably.

Schematic diagram showing the first embodiment of the present invention The perspective view which shows the principal part of the embodiment Explanatory drawing showing defects that occurred on the surface of the conveyor belt Graph diagram used to detect defects Photograph showing an example of image data acquired by the imaging device Photograph showing an example of image data acquired by the imaging device Photograph showing an example of image data acquired by the imaging device Photograph showing an example of image data acquired by the imaging device Schematic diagram showing a second embodiment of the present invention Schematic diagram showing the third embodiment of the present invention The perspective view which shows the principal part of 3rd embodiment. Schematic diagram showing the fourth embodiment of the present invention (A) Schematic diagram showing the fifth embodiment of the present invention, (b) Schematic diagram showing an example of the situation at the time of defect detection in (a), (c) For repairing defects after (b) Schematic diagram showing an example of a situation where the work area has stopped The perspective view which shows the principal part by the optical sensor of 5th embodiment The perspective view which shows the principal part by the IC tag reader of 5th embodiment The conceptual diagram which shows the principal part by the IC tag reader of 6th embodiment

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. This embodiment is a conveyor belt defect detection device 10 (hereinafter referred to as a defect detection device 10) used in a belt conveyor device 1 (hereinafter referred to as a conveyor device 1) including an endless conveyor belt 2. .

  As shown in FIG. 1, the conveyor device 1 is configured such that an endless conveyor belt 2 is wound between a driving pulley 3 and a driven pulley 4. The conveyor belt 2 extends in a longitudinal shape with a constant width W and is formed in an annular shape by connecting both ends in the longitudinal direction. The conveyor belt 2 is moved in the longitudinal direction by the rotation of the driving pulley 3, and the transported material placed on the conveyor belt 2 near the driven pulley 4 is conveyed toward the driving pulley 3. The

  A driving device 8 for operating the conveyor belt 2 along the longitudinal direction is connected to the driving pulley 3. The drive device 8 includes a drive source such as a motor, a power source that supplies electric power to the motor, a control device that controls rotation of the motor, and the like.

  A driving device is not connected to the driven pulley 4. The pulley 4 on the driven side rotates following the movement in accordance with the movement of the conveyor belt 2 along the longitudinal direction.

  The conveyed product falls at the reversing part b of the conveyor belt 2 near the pulley 3 on the driving side and is transferred to the next process. In FIG. 1, another conveyor device B provided adjacent to the downstream side is disposed as the next step. In addition, the reversing part b here is a place where the conveyor belt 2 changes its direction by 180 degrees from the feeding side belt a to the returning side belt c as shown in FIG.

  A scraper device 7 for scraping off deposits on the surface of the conveyor belt 2 is provided below the reversing portion b or on the return side belt c downstream of the reversing portion b. The scraper device 7 is configured to press a plate-like member made of rubber, resin, or the like against the surface of the conveyor belt 2 to scrape off deposits.

  The configuration of the defect detection device 10 includes an imaging device 11 that acquires three-dimensional image data of the surface of the conveyor belt 2 and a control unit that controls the imaging device 11. The control means includes a defect detection means 13 for detecting a defect present on the surface of the conveyor belt 2 based on the acquired three-dimensional image data, and an alarm means 14 for issuing an alarm when the defect detection means 13 detects a defect; It has.

  The imaging device 11 has a function of acquiring unevenness existing on the surface of the conveyor belt 2 with three-dimensional image data while operating the conveyor belt 2. As the imaging device 11, a known device that can acquire unevenness of an object as image data using various waves such as ultrasonic waves, radar waves, laser light, and electromagnetic waves as a medium can be employed. In this embodiment, an example in which the imaging device 11 using laser light is employed is shown. Specific examples include XG-X2000 manufactured by Keyence Corporation. By using the three-dimensional image generation method using the light cutting method, it is possible to increase the detection power of defects in the moving conveyor belt 2.

  As shown in FIG. 2, a plurality of imaging devices 11 are arranged along the width direction of the conveyor belt 2. In FIG. 2, a total of five imaging devices 11a, 11b, 11c, 11d, and 11e are arranged in parallel on a straight line. The number of the imaging devices 11 can be appropriately set according to the width W of the conveyor belt 2 and the area and angle of view that can be covered by one imaging device 11.

  As shown in FIG. 1, the imaging device 11 is disposed toward the lower surface of the return side belt c of the conveyor belt 2. In the case of the return side belt c, the conveyed product is not interposed between the conveyor belt 2 and the imaging device 11, so that the three-dimensional image data can be reliably acquired.

  In this embodiment, since the imaging device 11 is disposed on the return side belt c on the downstream side of the scraper device 7, there is almost no deposit on the conveyor belt 2, which is optimal for obtaining three-dimensional image data. is there.

  Each of the imaging devices 11 a to 11 e is connected to a control unit by a cable 12 and supplies power to the defect detection unit 13 through the cable 12 and transmits information. However, the imaging apparatus 11 itself may be provided with the functions of the defect detection means 13 and the alarm means 14.

  In order to acquire the three-dimensional image data on the surface of the conveyor belt 2, each of the imaging devices 11a to 11e includes a laser beam irradiation mechanism and an image receiving mechanism that receives the reflected light. Here, in order to acquire 3D image data, it is necessary that each of the imaging devices 11a to 11e includes a plurality of combinations of a pair of irradiation mechanisms and image receiving mechanisms. The same applies to the case of the imaging device 11 other than laser light.

  As the conveyor belt 2 moves in the longitudinal direction, the laser light emitted from the irradiation mechanism strikes the surface of the conveyor belt 2 and is reflected, and the image receiving mechanism sequentially scans the reflected light to obtain image reception data. The density of the received image data to be acquired, that is, the acquisition pitch of the acquired image data in the belt width direction and the acquisition pitch in the belt longitudinal direction can be appropriately set based on the required inspection accuracy. It is also possible to acquire substantially continuous information (information that is not intermittent) along the belt width direction and the belt longitudinal direction. Based on the received image data, the control means acquires three-dimensional image data through calculation.

  The defect detection means 13 has a function of determining the presence or absence of defects based on these three-dimensional image data. If the depth of the concave portion or the height of the convex portion existing in the three-dimensional image data, or the area of the concave portion or the convex portion (area in the plan view of the conveyor belt 2) exceeds a predetermined threshold value, It is set so as to be determined as a defect. The defect determined here means a defect in a state where it is necessary to immediately stop and repair the device. The determination of being a defect may be determined only by the depth of the concave portion or the height of the convex portion, or may be determined by combining the depth of the concave portion, the height of the convex portion, and the area thereof.

  Here, a defect may be determined by adding a condition of the shape of the concave portion or the convex portion (the shape in plan view). For example, when it is recognized that the shape of the concave portion is a crack extending in the longitudinal direction, such as a defect indicated by D in FIG. 2 or FIG. 3, the depth of the concave portion, the height of the convex portion, or the concave portion or The threshold value of the area of the convex portion can be set lower than in the case of defects having other shapes. In the case where the defect is a crack extending in the longitudinal direction, the urgency is higher than that of a defect of another type, so such a setting is effective.

  The alarm means 14 has a function of transmitting an alarm by sound or light and transmitting it to the manager of the apparatus and stopping the operation of the conveyor belt 2 when the defect detection means 13 determines that there is a defect.

  When a defect is found, the alarm means 14 automatically stops the operation of the conveyor belt 2, so that the expansion of the defect can be prevented. Here, the alarm means 14 does not stop the operation immediately, but switches the operation of the conveyor belt 2 to a low speed, and the operation is completely stopped after the inspector visually confirms the result of the determination. You may do it.

  FIG. 4 is a graph showing the depth of unevenness configured for the defect detection means 13 to detect a defect based on the three-dimensional image data. The horizontal axis represents the distance in the longitudinal direction of the conveyor belt 2, but a graph in which this is set in the width direction of the conveyor belt 2 can also be created. The vertical axis represents the depth of the recess as a defect. The lowermost straight portion is the original surface of the conveyor belt 2. When the depth of the recess exceeds a predetermined threshold, the recess is determined as a defect.

  In the present invention, the imaging device 11 corresponds to 3D image data covering a planar area, and a plurality of the imaging devices 11 are provided along the belt width direction of the conveyor belt 2. Convex depth information on the surface of the conveyor belt 2, height information, volume of the concavity and convexity, and information on the volume and cross-sectional area that could not be obtained by inspection based on the density of images such as Thus, multi-faceted inspection based on various information is possible. Further, the imaging device 11 includes a plurality of pairs of irradiation mechanisms and image receiving mechanisms, and performs measurement and imaging with respect to a certain place on the surface of the conveyor belt 2 by the plurality of irradiation mechanisms and image receiving mechanisms. The unevenness evaluation and the defect evaluation are more reliable.

  FIG. 5 shows an example of 3D image data. A defective portion is displayed in a perspective manner, and it is easy to visually recognize a defect on the surface of the conveyor belt 2.

  FIG. 6 is image data in plan view around the defective portion, created based on the height data of the surface of the conveyor belt 2. FIG. 7 shows a black and white image converted based on the height data based on the image data of FIG. The part that exceeds a certain height (depth) is expressed in black, and the rest is expressed in white. FIG. 8 is an image showing the stability of the same part. The colored part is the part that recognizes the shading change. Based on these pieces of information, the three-dimensional image data shown in FIG. 5 is created. Since the three-dimensional image data has information on the unevenness of the surface of the conveyor belt 2 as numerical values, the defect can be determined based on these numerical values, or the three-dimensional image based on those numerical values. It can also be carried out according to the color grade, the shade grade, etc. appearing in the data.

  As described above, in the present invention, the imaging device 11 that acquires three-dimensional image data is used when determining the surface defect of the conveyor belt 2. Since the imaging device 11 corresponds to the three-dimensional image data covering a planar area, and further includes a plurality of the imaging devices 11 along the belt width direction of the conveyor belt 2, In addition, a three-dimensional stereoscopic image of the surface of the conveyor belt 2 can be acquired without providing a movable part in the camera or sensor. For this reason, the malfunction of a device and generation | occurrence | production of a detection error can be prevented more reliably. That is, the defect which generate | occur | produced in the conveyor belt 2 can be detected more reliably. Further, since the three-dimensional image data is used, it is possible to more reliably determine the defect.

  Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is a defect detection apparatus 10a for a conveyor belt that is partially different from the first embodiment. As shown in FIG. 9, the configuration of the conveyor device 1 is basically the same as that of the first embodiment shown in FIG.

  The configuration of the defect detection device 10a includes, in addition to the imaging device 11, a temperature acquisition device 15 that acquires temperature data on the surface of the conveyor belt while operating the conveyor belt. Control means for controlling both are provided. The control means includes defect detection means 13a that detects defects present on the surface of the conveyor belt 2 by referring to temperature data together with the three-dimensional image data acquired by the imaging device 11. Moreover, the alarm means 14 which transmits an alarm when the defect detection means 13a detects a defect is the same as that of the first embodiment.

  In the second embodiment, the imaging device 11 and the temperature acquisition device 15 are arranged toward the lower surface of the feed belt a of the conveyor belt 2 as shown in FIG. Even in the feeding belt a, a space is provided between the pulleys 3 and 4, and wiring or the like can be introduced from both width directions of the conveyor belt 2 to be installed in this space. Since no conveyed product is interposed between the conveyor belt 2 and the image pickup device 11, the three-dimensional image data and the temperature data can be obtained with certainty. In addition, by adopting this form, when the transported object is a high-temperature object such as coke or coal, it is possible to observe in real time the state of applying a thermal load in the state of transporting, and it is difficult to appear on the surface. Defects are easier to detect.

  The temperature acquisition device 15 has a function of acquiring the temperature of the surface of the conveyor belt 2 while operating the conveyor belt 2 in conjunction with the imaging device 11. It is desirable that the temperature data correspond to the three-dimensional image data acquired by the imaging device 11 and the position on the conveyor belt 2. Judgment of defect detection by unevenness and defect detection by temperature together makes it possible to make a more accurate determination. This is because if there is a defect such as a crack or a dent, the temperature may change from the periphery of the defect. As the temperature acquisition device 15, a well-known device that acquires temperature data by sensing infrared rays or the like from a remote location such as thermography can be employed. In this embodiment, a temperature acquisition device 15 using infrared rays is described.

  Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment is a conveyor belt defect detection device 10b in which the configurations of the first embodiment and the second embodiment are further combined. As shown in FIG. 10, the configuration of the conveyor device 1 is basically the same as that of the first embodiment shown in FIG.

  In the third embodiment, the set of the imaging device 11 and the temperature acquisition device 15 is arranged on each of a set directed to the lower surface of the feeding belt a of the conveyor belt 2 and a set directed to the lower surface of the return belt c. To do. In the former case, the inner surface side of the conveyor belt 2 is inspected, and in the latter case, the outer surface side of the conveyor belt is inspected. In this third embodiment, it is possible to detect defects on both surfaces. Even when there is a defect that cannot be recognized from one surface, it may be detected from the other surface, so that the defect detection accuracy can be further improved.

  An enlarged view of the detection portion of this embodiment is shown in FIG. In accordance with the imaging devices 11a to 11e, the temperature acquisition devices 15a to 15e are arranged in parallel on a straight line so that the temperature at the same location can be observed. The number of the imaging devices 11 and the temperature acquisition devices 15 can be appropriately set according to the width W of the conveyor belt 2 and the area and angle of view that can be covered by one imaging device 11 and the temperature acquisition device 15.

  The third embodiment further includes a marker throwing device 16 that throws a color ball of fluorescent paint or the like toward a location where the defect detecting means 13b can detect that there is a defect. If the conveyor belt 2 is vast, has a small defect, or is difficult to visually recognize from the outside, it may be difficult to visually find where the defect is. Therefore, confirmation can be facilitated by making it possible to discriminate the location where the defect detection means 13b can detect a defect. As the color ball, a general ball that adheres the fluorescent paint stored inside to the collision location can be used. The marking means 17 for executing this is a firing position so as to appropriately hit the detection position based on the distance between the observation point by the imaging device 11 or the temperature acquisition device 15 and the range of the marking means 17 and the transport speed of the conveyor belt 2. Calculate the color ball. When the vehicle is decelerated by the alarm means 14, the calculation including the deceleration is performed.

  Further, a fourth embodiment will be described with reference to FIG. In this embodiment, a set of the imaging device 11 and the temperature acquisition device 15 oriented to correspond to the front and back of the same location is disposed on each of the outer surface side and the inner surface side of the return side belt c. The defect detection means 13c can detect a defect with higher accuracy by observing the same part from both sides. In particular, even when it is difficult to determine whether or not a defect is present from information on one side, it is possible to make a highly accurate judgment by combining information from both sides. Further, a color ball is thrown out from the marker throwing device 16 so that the detected location can be accurately marked.

  Next, a fifth embodiment will be described with reference to FIGS. In this embodiment, the imaging device 11 and the temperature acquisition device 15 are imaging points on the conveyor belt 2 (S: actually a wide band-like imaging region, not a point, but described as a point on an endless orbit in the traveling direction. ) Is detected by imaging or the like. In addition to these devices, a position designation mechanism 22 serving as a reference point (B) is provided at one point on the conveyor belt 2. Furthermore, a reference point specifying means 21 for checking a reference time point (t0) when the position specifying mechanism 22 has passed the observation point (O) is provided so as to face the conveyor belt 2.

  In FIG.13 and FIG.14, the reflection sheet attached to the outer surface of the conveyor belt 2 is shown as an example as the position designation | designated mechanism 22 used as a reference | standard point (B). An example in which a laser sensor that continues to irradiate laser light to a position through which the reflection sheet (22) passes and can detect that when reflected is used as the reference point specifying means 21 will be described. Since the conveyor belt 2 does not have an end, it is necessary to define the position on the conveyor belt 2 as a position from a certain reference point in order to specify the position in the traveling direction on the conveyor belt 2. The reference point (B) to which the reflection sheet (22) is attached is set as the origin. An example of such an optical sensor is an optical sensor (PR-G series) manufactured by Keyence Corporation. The reflection sheet (22) only needs to have sufficient reflection performance to be detected by the optical sensor, and is preferably flexible enough to be bent along the bending of the conveyor belt 2.

  In this embodiment, the position of the defect (E) on the conveyor belt 2 is acquired as data of a relative position from the reference point (B). Basically, the travel direction or the length in the direction opposite to the travel direction is indicated, or the positive and negative values with respect to those directions are indicated. Here, a case where the traveling direction is positive is shown as an example. The position of defect E is shown as a distance | D | In addition, D itself can take a negative value. As one of the values for calculating this, the position L of the imaging point (S) with the traveling direction X on the conveyor belt 2 relative to the observation point (O) as positive is defined. In addition, you may prescribe | regulate reverse with respect to the advancing direction.

  In FIG. 13, the distance between the observation point (O) where the reference point specifying means (here, the optical sensor 21) is installed and checked and the imaging point (S) at which the imaging device 11 or the like captures an image is represented by | L |. In this example, since there is an imaging point (S) behind the traveling direction X from the observation point (O), the value of L indicating the position of the imaging point (S) is a negative value.

  FIG. 13A is a cross-sectional view of the timing when the reflection sheet (22) serving as the reference point (B) passes through the observation point (O) and is detected by the optical sensor (21). This timing is set as a reference time point (t0). In the drawing, the defect E is not observed at this stage, but the defect E may be detected by the imaging device 11 at this timing depending on circumstances.

  FIG. 13B shows a situation in which the defect E is detected at an imaging point (S) where the imaging device 11 and the temperature acquisition device 15 detect the defect E by imaging at a certain time (t1). The elapsed time from the reference time point (t0) to the time point (t1) is defined as time (T). During this time (T), the conveyor belt 2 moves by a length (v × T) with respect to the moving speed (v). As a result, the position D of the defect E on the conveyor belt 2 with respect to the reference point (B) is D = −v × TL. Since it is behind the reference point (B) with respect to the traveling direction, it is obtained as a negative value. The distance | D | is | −v × TL |. By such calculation, the reference point detection function can specify the position of the defect E with respect to the reference point (B). However, when this distance | D | is longer than half of the entire circumference (F) of the conveyor belt 2, it can be seen that there is a defect E at a position separated by (F / 2− | D |) in the opposite direction. .

  Note that if the imaging point (S) is more positive in the direction of travel than the observation point (O), L takes a positive value, but the above formula is handled in the same way.

  In the embodiment of FIG. 13C, when the relative position on the conveyor belt 2 with respect to the reference point (B) of the defect E thus identified is located in a work area suitable for repairing the defect E. The progress of the conveyor belt 2 is stopped at (t2). Depending on the usage environment, the conveyor belt 2 may range from several hundred meters to several thousand meters. If a defect E is detected, repair personnel move from end to end in order to repair the defect E. It is useless to do. For this reason, since the relative position of the defect E with respect to the reference point (B) is known, the conveyor is closest to the work area suitable for repair from the reference time point (t0) through which the reference point (B) passes. If a repair stop function for stopping the belt 2 is provided, repair work can be performed quickly and easily. The work area is, for example, a place for repair personnel.

  FIG. 15 shows an embodiment in which the position specifying mechanism and the reference point specifying means are different examples. The position designation mechanism is a non-contact passive short-range wireless communication tag 23, and the reference point specifying means is an IC tag reader 24 capable of reading the short-range wireless communication tag. By adopting the passive type, it is not necessary to supply power to the short-range wireless communication tag 23 itself, and the passage of the reference point (B) can be detected by the magnetic field from the IC tag reader 24. Becomes easier. Moreover, it has the advantage that it can detect, without exposing a position designation | designated mechanism to the surface of the conveyor belt 2 by being non-contact. This is particularly effective when the surface is a transported item that tends to become dirty. The type of the short-range wireless communication tag 23 is not particularly limited, but a detection range of about 10 cm or less is desirable in order to increase the accuracy of the passing point of the reference point (B).

  As another method for acquiring the relative position (distance) on the conveyor belt 2 with high accuracy, it is possible to detect a defect from the reference time point and determine the stop position of the conveyor belt 2 until a specific time point. There is a method of counting the number of rotations of the pulleys (3, 4). An example of this mechanism is shown in FIG. 16 as a sixth embodiment. A non-contact passive short-range wireless communication tag (IC tag 31) is installed on the inner side near the outer peripheral surface of the pulley (3, 4). On the other hand, an IC tag reader 32 capable of reading the approach of the IC tag 31 is installed so as to be opposed to any position on the outer periphery of the pulley (3, 4). Assuming that the radius of the pulley (3, 4) is R, the conveyor belt 2 advances by 2πR after the radio wave of the IC tag 31 is detected by the IC tag reader 32 until the next detection. For this reason, if the number of counts in which the approach of the IC tag 31 is detected between the first detection which is the reference time and the specific time is C, the distance traveled by the conveyor belt 2 up to the specific time is 2πRC. The range is 2πR (C + 1) or less. Usually, since the radius R of the pulleys (3, 4) is sufficiently small with respect to the length of the conveyor belt 2, if it can be narrowed down to this range, the accuracy is practically sufficient. In this way, with the method of installing the IC tag 31 on the pulley, there is no need to tear the surface of the conveyor belt 2 to introduce an IC tag or to order / install a new conveyor belt 2 having an IC tag. It can be easily and inexpensively introduced into already installed facilities.

  In the case of measuring the distance by the method according to FIG. 16, the position can be specified by marking a reference position on the conveyor belt 2 as a reference point and measuring the distance 2πRC from this reference point. If only marking is required, the conveyor belt 2 can be introduced without being damaged.

  Further, the count number C may be transmitted from the IC tag reader 32 to the defect detection apparatus 10, and the count may be repeated or the number may be reset as appropriate. In this case, it is desirable that the value of R is input to the defect detection apparatus 10 in advance and held. When obtaining the distance 2πRC, it can be quickly calculated from the values of R and C.

  Further, as another method for counting the number of rotations in order to acquire the relative position, the following method can be cited. A proximity sensor or a photoelectric sensor may be used instead of the IC tag and the IC tag reader in FIG. Similarly, it can be introduced without damaging the conveyor belt 2.

1 Belt conveyor device (conveyor device)
2 Conveyor belt 3 Driving pulley 4 Driven pulley 7 Scraper device 8 Driving device 10, 10 a, 10 b, 10 c Defect detection device 11, 11 a to 11 e Imaging device 12 Cable 13, 13 a, 13 b, 13 c Defect detection means 14 Alarm Means 15, 15a to 15e Temperature acquisition device 16 Marker throwing device 17 Marking means 21 Optical sensor 22 Reflective sheet 23, 31 IC tag 24, 32 IC tag reader B Reference point D Distance to defect E Defect O Observation point L Optical sensor To position of imaging device S imaging point T time t0 reference time point t1 observation time point v transport speed X traveling direction

Claims (10)

A conveyor device (1) comprising an endless conveyor belt (2);
A drive device (8) for moving the conveyor belt (2) along the longitudinal direction;
An imaging device (11) for acquiring three-dimensional image data of the surface of the conveyor belt (2) while operating the conveyor belt (2);
A defect detection means (13) for detecting defects present on the surface of the conveyor belt (2) based on the three-dimensional image data;
Alarm means (14) for issuing an alarm when the defect detection means (13) detects a defect;
With
The said imaging device (11) is a defect detection apparatus of the conveyor belt arranged in multiple numbers along the width direction of the said conveyor belt (2). The defect detection device for a conveyor belt according to claim 1, wherein the imaging device (11) is arranged toward a lower surface of a return side belt (c) of the conveyor belt (2). The defect detection device for a conveyor belt according to claim 1 or 2, wherein the imaging device (11) is arranged toward a lower surface of a feeding belt (a) of the conveyor belt (2). The defect detection apparatus of the conveyor belt in any one of Claims 1-3 arrange | positioned toward the upper surface of the return side belt (c) of the said conveyor belt (2). The scraper device (7) for scraping off the deposits on the surface of the conveyor belt (2) is a reverse part (b) or return side of the conveyor belt (2) from the feed belt (a) to the return belt (c). In preparation for the belt (c),
The said imaging device (11) is a defect detection apparatus of the conveyor belt in any one of Claims 2-4 arrange | positioned in the downstream of the said scraper apparatus (7). The said alarm means (14) is a defect detection apparatus of the conveyor belt as described in any one of Claims 1-5 which has a function which stops the operation | movement of the said conveyor belt (2). One point of the conveyor belt (2) is provided with a position designation mechanism that serves as a reference point (B),
A reference point specifying means for checking a reference time point (t0) relative to the conveyor belt (2) when the position specifying mechanism has passed the observation point (O);
A distance (| L |) from an imaging point (S) imaged by the imaging device to an observation point (O) checked by the reference point specifying means;
The moving speed (v) of the conveyor belt (2);
A time (T) from the reference time point (t0) to a time point (t1) at which the defect detection means detects a defect (E);
And a reference point detection function for calculating a distance (| D |) from the reference point (B) of the defect (E) in the conveyor belt (2).
The defect detection apparatus of the conveyor belt as described in any one of Claims 1-6.   The conveyor belt defect detection device according to claim 7, wherein the position specifying mechanism is a reflection sheet, and the reference point specifying unit is an optical sensor that detects reflection of light by the reflection sheet.   The defect of the conveyor belt according to claim 7, wherein the position specifying mechanism is a non-contact passive short-range wireless communication tag, and the reference point specifying means is an IC tag reader capable of reading the short-range wireless communication tag. Detection device. The conveyor belt defect detection device according to any one of claims 7 to 9, further comprising a repair stop function for stopping the conveyor belt by positioning the defect in a work area for repairing the defect.