JP7538533B2 - Rolling monitoring system for pipe conveyors - Google Patents

Description

This invention relates to a system that uses sensors to monitor whether rolling, a phenomenon in which the belt meanders, occurs in a pipe conveyor.

The following Patent Document 1 describes a pipe conveyor suitable for transporting crushed stone and powder, as shown in Figure 10. This pipe conveyor rolls an endless belt 53 around a head pulley 51 and a tail pulley 52 into a pipe shape in the middle of the path, and transports the transported object 50 while wrapping it around it, preventing the load from spilling or dust from scattering on the carrier side, and preventing environmental pollution caused by the transported object 50 adhering to the surface of the belt 53 falling off on the return side.

The pipe conveyor described in Patent Document 1 is characterized in that magnets 54, 55 are attached to the back surface of the outer portion and the front surface of the inner portion of the overlapping portion of belt 53, respectively, and a magnetic sensor is used to detect twisting of belt 53.

In addition, the following Patent Document 2 describes a rolling monitoring system that, as shown in Figure 11, projects light from two lighting fixtures 62, 63 that are perpendicular to the circumferential direction and have different brightness toward the overlapping portion 61a of a belt 61 rolled into a pipe, generating a shadow at the edge of the overlapping portion 61a of the belt 61, and processes an image captured by a fixed camera 64 halfway between the two light projection positions with an image processing amplifier 65 to detect the position of the overlapping portion 61a of the belt 61, and controls the centering roller so that the position is constant, thereby avoiding rolling. With this system, there is no need to attach magnets or other attachments to the belt 61 for rolling detection.

JP 2007-91356 A JP 2005-255314 A

However, the rolling monitoring system described in Patent Document 2 requires that strong light be emitted from the lighting devices 62 and 63 toward the overlapping portion 61a of the belt 61, which consumes a lot of power. In addition, if the strong light enters the field of vision of nearby workers in a dark tunnel, it may cause dazzlement.

In addition, because the captured image changes depending on the change in the surrounding brightness, detection is unstable, and measures such as keeping the surrounding illuminance constant or installing an enclosure to block external light are required.

In addition, if the shape of the inspection surface of the belt 61 changes depending on whether or not there is an article being transported by the belt 61, the way the light hits the belt will change, making it difficult to perform an accurate inspection. In addition, the inspection surface of the belt 61 will shift from the focal position of the fixed camera 64, making it difficult to obtain a clear image and making image processing difficult.

Furthermore, if the relationship between the inside and outside of the overlapping portion 61a of the belt 61 is reversed, the shadows cast by the light from the two lighting devices 62, 63 will become unclear, making it impossible to detect the overlapping portion 61a of the belt 61, and there is a risk that serious abnormalities will not be detected.

The objective of this invention is to stably detect the rolling of the belt and the reversal of the overlapping part in a pipe conveyor using simple equipment without emitting strong light and without contact, while saving power.

In order to solve the above problems, the present invention provides a rolling monitoring system that is attached to a pipe conveyor that rolls an endless belt that travels in a circular motion into a pipe shape and transports objects by wrapping the belt around the objects, and detects whether the belt is rolling or not as it travels.
a plurality of non-contact sensors are arranged at intervals in the circumferential direction of the belt, the non-contact sensors scanning the outer periphery of the belt rolled into a pipe shape to measure displacement in the height direction;
Based on the measurement results of the sensor, an image is created for every fixed number of lines, and the point where the height measured by the sensor changes significantly and discontinuously is detected as the position of the outer edge of the overlapping portion of the belt.

The position coordinates of the edge are also compared with a preset threshold value for determining position to determine whether the belt is running normally or rolling.

In addition, a profile image showing the cross-sectional shape of the belt within the range of the image is created, and the size of the step at the edge position is measured.

The size of the step at the edge position is measured using either the left or right side in the width direction of the belt as a reference, and the size of the step is compared with a preset threshold value for determining the overlap state to determine whether the relationship between the inside and outside of the overlapping portion of the belt is normal or inverted.

In the rolling monitoring system for pipe conveyors according to this invention, a sensor that detects the position of the outer edge at the overlapping part of the belt scans the outer circumference of the belt rolled into a pipe shape to measure the displacement in the height direction, and the presence or absence of belt rolling is determined by comparing the position coordinates of the edge detected from the change in height with a threshold value for position determination. This means that there is no need to shine strong light onto the overlapping part of the belt, power consumption is reduced, the system is not significantly affected by the brightness of the surroundings, and rolling can be detected stably even if the shape of the inspection surface of the belt changes.

In addition, by comparing the size of the step measured by the sensor with a threshold value for determining the overlap state, it is possible to detect the reversal of the overlap section, which is a sign of twisting of the belt, so changes in the rolling direction can be detected in advance, and rolling can be dealt with quickly even on curved conveyors where the reversal of the overlap section is likely to occur.

Then, an image of the overlapping parts of the belt and a profile image showing the cross-sectional shape are created based on the detection values of the sensor, so that the monitor can accurately detect abnormalities in the running condition of the belt without relying on images taken by a camera and can take action to eliminate rolling, eliminating the need to install large-scale equipment such as a rolling correction device linked to a sensor.

(1A) is an overall schematic side view of a pipe conveyor equipped with a rolling monitoring system according to the present invention, and (1B) is a longitudinal front view of a head chute. FIG. 2A is a cross-sectional view showing a portion where the belt is rolled into a pipe shape by rollers; FIG. 2B is a side view showing the arrangement of the rollers. A vertical cross-sectional view showing the arrangement of sensors and a rolling detection image of the above 13A and 13B are diagrams showing the state of the belt when no rolling occurs, and an image and a profile image created based on the detection values of the sensor; 13A and 13B are diagrams showing the state of the belt rolling to one side, an image and a profile image of the belt shown in FIG. 13A and 13B are diagrams showing the state of the belt rolling toward the other belt, an image image, and a profile image of the belt according to the above; 1 is a diagram showing the state of the belt with the overlapping portion reversed, an image image and a profile image of the same; FIG. 13A and 13B are diagrams showing the state of the belt in which the overlapping portion cannot be detected, an image image, and a profile image of the belt; 13A and 13B are diagrams showing the state of the belt with the outer side of the overlapping portion significantly raised, as well as an image and a profile image thereof. Schematic perspective view showing a pipe conveyor described in Patent Document 1. A schematic diagram showing a rolling monitoring system using image processing with a fixed camera in a pipe conveyor described in Patent Document 2.

The following describes an embodiment of the invention with reference to the attached drawings.

Figures 1 and 2 show a pipe conveyor 10 that is positioned to extend toward the tunnel mouth, perpendicular to the upstream trough conveyor 1, in order to transport the excavated soil outside the tunnel during tunnel construction. The excavated soil discharged from the trough conveyor 1 is accumulated in the head chute 2, from which it falls and is supplied to the pipe conveyor 10. The head chute 2 is equipped with an electrically operated buffer plate 3, and the supply position of the excavated soil relative to the pipe conveyor 10 can be adjusted by swinging the buffer plate 3.

The pipe conveyor 10 conveys excavated soil by wrapping it around an endless belt 13 that is wound around a head pulley 11 and a tail pulley 12 and rolling it into a pipe shape using rollers 14 at the midpoint of the path on both the carrier side and the return side.

As a rolling monitoring system, the pipe conveyor 10 is provided with a sensor 20 that scans the outer circumference of the belt 13 to measure the height displacement at a position immediately after the belt 13 is rolled into a pipe shape on the carrier side. The sensor 20 may be located in the middle of the path of the pipe conveyor 10 or near the head, depending on the dynamic characteristics of the belt 13 and the surrounding conditions. As shown in Figure 3, multiple sensors 20 (three in the illustrated example) are arranged at intervals in the circumferential direction above the belt 13.

As the sensor 20, for example, a laser displacement meter LJ-X8900 or IX-150 manufactured by Keyence Corporation that emits a blue semiconductor laser can be used, or a sensor that emits diffuse infrared light to capture the shape of the belt 13 and perform image processing.

In this rolling monitoring system, a laser beam is emitted from the sensor 20 toward the outer circumference of the belt 13, and the heightwise displacement of the outer circumference of the belt 13 is measured by the reflection of the beam to determine whether the position of the outer edge 13b of the overlapping portion 13a of the belt 13 is within the normal range or in a slightly or severely abnormal position. Usually, two or three sensors 20 can cover almost the entire upper half of the outer circumference of the belt 13 rolled into a pipe shape.

Specifically, as shown in FIG. 4, an image is created for every certain number of lines based on the measurement results of the sensor 20, and a profile image is created that represents the cross-sectional shape within the range of the image. Note that the diagram showing the state of the belt 13, the image, and the profile image are reversed left to right.

The point where the height measured by the sensor 20 changes discontinuously is detected as the position of the edge 13b that is on the outside of the overlapping portion 13a of the belt 13, and the size of the step at the position of the edge 13b is measured. At this time, the size of the step is corrected by the program based on the position of the edge 13b.

Then, the position coordinates of the edge 13b are compared with a preset threshold value for determining the position to determine whether the belt 13 is running normally or rolling. Figure 4 shows the state in which the belt 13 is running normally without rolling.

Figure 5 shows the state of the belt 13 when it is rolling in one direction (clockwise in the figure) and the image and profile images that were created, and Figure 6 shows the state of the belt 13 when it is rolling in the other direction (counterclockwise in the figure) and the image and profile images that were created.

The size of the step at the edge 13b is measured using either the left or right side in the width direction of the belt 13 as a reference, and the size of the step is compared with a preset threshold value for determining the overlap state, making it possible to determine whether the relationship between the inside and outside at the overlap portion 13a of the belt 13 is normal, as shown in Figure 4, or whether the relationship between the inside and outside is reversed, as shown in Figure 7.

As shown in Figure 8, when the overlapping portion 13a is located in the lower half of the outer circumference of the belt 13, the position of the edge 13b of the belt 13 cannot be detected, so it is determined that an abnormality has occurred, such as the belt 13 rolling extremely significantly.

In addition, with this rolling monitoring system, as shown in Figure 9, if the overlapping portion 13a of the belt 13 is in the upper half, the position of the edge 13b of the belt 13 can be detected without any problems even if the outer belt 13 is significantly raised.

As described above, in this pipe conveyor rolling monitoring system, a sensor 20 that detects the position of the outer edge 13b at the overlapping portion 13a of the belt 13 scans the outer circumference of the belt 13 rolled into a pipe shape to measure the displacement in the height direction, and the presence or absence of rolling of the belt 13 is determined by comparing the position coordinates of the edge 13b detected from the change in height with a threshold value for position determination. Therefore, there is no need to shine strong light onto the overlapping portion 13a of the belt 13, power consumption is reduced, the system is not greatly affected by the brightness of the surroundings, and rolling can be stably detected even if the shape of the inspection surface of the belt 13 changes depending on the presence or absence of a transported object.

In addition, by comparing the size of the step measured by the sensor 20 with a threshold value for determining the overlap state, it is possible to detect the reversal of the overlap portion 13a, which is a precursor to twisting of the belt 13, so that changes in the rolling direction can be detected in advance, and rolling can be dealt with quickly even in curved conveyors where reversal of the overlap portion 13a is likely to occur.

Then, an image of the overlapping portion 13a of the belt 13 and a profile image showing the cross-sectional shape are created based on the detection value of the sensor 20. This allows the monitor to accurately detect abnormalities in the running condition of the belt 13 and take action to eliminate rolling, without relying on images taken by a camera. This eliminates the need to introduce large-scale equipment such as a rolling correction device linked to the sensor 20.

The rolling monitoring system may be linked to the control unit of the buffer plate 3 of the head chute 2 shown in FIG. 1, and based on the signal indicating the direction and degree of rolling of the belt 13 sent from the rolling monitoring system, the buffer plate 3 of the head chute 2 may be swung to adjust the supply position of the excavated soil in the width direction of the belt 13, thereby automatically correcting the rolling of the belt 13.

In addition, a group of rollers 14 supporting the belt 13 may be made into electrically operated automatic centering rollers, and based on a signal indicating the direction and degree of rolling of the belt 13 sent from the rolling monitoring system, the automatic centering rollers may be swung left and right relative to the running direction of the belt 13 to automatically correct the rolling of the belt 13.

REFERENCE SIGNS LIST 1 Trough conveyor 2 Head chute 3 Buffer plate 10 Pipe conveyor 11 Head pulley 12 Tail pulley 13 Belt 13a Overlap portion 13b Edge 14 Roller 20 Sensor

Claims (4)

A rolling monitoring system is attached to a pipe conveyor (10) in which an endless belt (13) that travels in a circular motion is rolled into a pipe shape to wrap around an object to be conveyed, and detects whether the belt (13) is rolling or meandering as it travels.
a plurality of non-contact sensors (20) for measuring displacement in the height direction by scanning the outer periphery of the pipe-shaped rolled belt (13) within an angular range spreading in a fan shape; and
A rolling monitoring system for a pipe conveyor, characterized in that an image is created for each fixed number of lines based on the measurement results of the sensor (20), and the point where the height measured by the sensor (20) changes significantly and discontinuously is detected as the position of the outer edge (13b) of the overlapping portion (13a) of the belt (13), and it is determined whether the position of the edge (13b) is within a normal range or within a mildly or severely abnormal range . The rolling monitoring system for a pipe conveyor according to claim 1, characterized in that the position coordinates of the edge (13b) are compared with a preset threshold value for determining the position to determine whether the belt (13) is running normally or is rolling. The rolling monitoring system for a pipe conveyor according to claim 1 or 2, characterized in that a profile image is created that represents the cross-sectional shape of the belt (13) within the range of the image, and the size of the step at the position of the edge (13b) is measured. The rolling monitoring system for a pipe conveyor according to claim 3, characterized in that the size of the step at the position of the edge (13b) is measured based on either the left or right side in the width direction of the belt (13), and the size of the step is compared with a preset threshold value for determining the overlap state to determine whether the relationship between the inside and outside at the overlap portion (13a) of the belt (13) is normal or inverted.

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