Chain measurement system

Abstract

To measure the wear of a chain while a device equipped with the chain is in operation.SOLUTION: A chain measurement system S comprises: a detection device 10 that detects an imaging timing of a drive chain 1 transporting a heavy object H, where the drive chain 1 comprises a ring-shaped outer link 5 and a ring-shaped inner link 6 arranged alternately in a longitudinal direction and connected to each other by pins 7; an imaging device 11 that, when detecting the imaging timing at which one outer link 5 is located in an imaging region, generates a picked-up image capturing a first inner link 6a connected to one end of the outer link 5 and a second inner link 6b connected to the other end of the outer link 5; and a measuring device 12 that measures wear of the drive chain 1 based on a distance between the first inner link 6a and the second inner link 6b included in the picked-up image.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a chain measurement system.

Background Art

[0002] The elongation measuring device of Patent Document 1 travels on the chain when the chain, which is formed by alternately connecting outer links and inner links, stops driving, and measures the elongation due to wear of the chain by calculating the distance between adjacent inner links.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to measure the elongation due to wear of the chain, the conventional elongation measuring device has to stop the operation of devices such as conveyors and escalators equipped with the chain, resulting in a problem that the time for inspecting the chain is limited.

[0005] Therefore, the present invention has been made in view of these points, and an object thereof is to measure the wear of a chain while a device equipped with the chain is operating.

Means for Solving the Problems

[0006] The chain measurement system according to an aspect of the present invention includes a detection device that detects an imaging timing for imaging a chain during conveyance of a heavy object, in which annular outer links and inner links are alternately arranged in the longitudinal direction and the outer links and the inner links are connected by pins, and an imaging device that generates an imaging image by imaging a first inner link connected to one end of the outer link and a second inner link connected to the other end of the outer link when detecting the imaging timing in which one of the outer links is located in an imaging region, and a measurement device that measures wear of the chain based on a distance between the first inner link and the second inner link included in the imaging image.

[0007] The chain measurement system further includes a first power transmission member arranged in front of the imaging region and a second power transmission member arranged behind the imaging region in a conveyance direction for conveying the heavy object, and a plurality of convex portions that fit into hole portions of the inner links may be formed on the first power transmission member and the second power transmission member.

[0008] One of the first power transmission member and the second power transmission member may have the convex portion fitting into the hole portion on a first surface of a circumferential surface of the chain in the longitudinal direction, and the other may have the convex portion fitting into the hole portion on a second surface opposite to the first surface of the circumferential surface.

[0009] When the first power transmission member and the second power transmission member rotate in the conveyance direction, a tension applied to the chain by the first power transmission member may be greater than a tension applied to the chain by the second power transmission member.

[0010] The chain measurement system further includes an irradiation device that irradiates the chain with transmitted light from a direction opposite to a direction in which the imaging device is provided in the chain, and the imaging device may generate the imaging image by imaging in a state where the irradiation device irradiates the chain with transmitted light.

[0011] The detection device may measure the distance between the detection device and the chain, and detect, as the imaging timing, the timing at which the measured distance is longer than a predetermined distance.

[0012] The chain includes at least one of the one or more outer links and the inner links to which an identification code for identifying a link is attached, and the measuring device may specify an identification number of at least one of the outer link and the inner link based on the identification code included in the captured image.

[0013] The measuring device may cause a display device to display the wear of the chain based on the distance between the first inner link and the second inner link in association with the identification number.

[0014] The chain may include a pusher for pushing a trolley that supports the heavy object in a transport direction for transporting the heavy object.

Advantages of the Invention

[0015] According to the present invention, there is an effect of measuring the wear of the chain while the device including the chain is operating.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0017] <Overview of the conveying device> FIG. 1 is a schematic diagram showing an example of the conveying device according to the present embodiment. FIG. 1 is a view of the conveying device seen from the side. The conveying device is, for example, a device such as a conveyor for conveying an object or an escalator for conveying a person. In FIG. 1, as an example of the conveying device, a conveyor C is shown.

[0018] In the conveyor C, a driving chain 1 extending in the conveying direction, a free rail 2 extending parallel to the driving chain 1 below the driving chain 1, front and rear free trolleys 3 (front free trolley 3a and rear free trolley 3b) running on the free rail 2, and a carrier 4 to which a heavy object H is suspended and passed to the front and rear free trolleys 3 are shown.

[0019] In the driving chain 1, annular outer links 5 (upper plate 5a and lower plate 5b) and inner links 6 are alternately arranged in the longitudinal direction, and the outer links 5 and the inner links 6 are connected by pins 7. On the lower plate 5b arranged in the driving chain 1, a pusher 8 for pushing the front and rear free trolleys 3 supporting the heavy object H in the conveying direction is provided so as to protrude downward. The rear free trolley 3b is provided with a dog 9 that can be freely engaged and disengaged with the pusher 8. In the conveyor C, as the driving chain 1 moves, the pusher 8 engages with the dog 9 and pushes the dog 9 to convey the heavy object H. The heavy object H is, for example, a device or component constituting a vehicle, such as an engine, a transmission, an axle, etc.

[0020] FIG. 2 is a diagram for explaining the wear of the drive chain 1. FIG. 2(a) shows the state before the drive chain 1 wears, and FIG. 2(b) shows the state after the drive chain 1 wears. In FIG. 2, the upper plate 5a and the lower plate 5b constituting the outer link 5 and the first inner link 6a are connected by the first pin 7a, and the upper plate 5a and the lower plate 5b and the second inner link 6b are connected by the second pin 7b. The distance between the end of the first inner link 6a and the end of the second inner link 6b (hereinafter sometimes referred to as "pitch") is distance L1 in FIG. 2(a) and a distance L2 longer than distance L1 in FIG. 2(b). Distance L1 is, for example, the distance at the time of manufacturing the drive chain 1.

[0021] In FIG. 2(b), for example, when the conveyor C conveys the heavy object H, a force M1 acts on the first pin 7a from the upper plate 5a, a force M2 acts on the first pin 7a from the lower plate 5b, and a force M3 acts on the first inner link 6a from the first pin 7a. Therefore, wear occurs on the first pin 7a and the first inner link 6a. Similarly to the first pin 7a and the first inner link 6a, wear also occurs on the second pin 7b and the second inner link 6b. As a result of the wear, the pitch changes from distance L1 to a distance L2 longer than distance L1.

[0022] As shown in FIG. 2, in the conveyor C, the wear of the drive chain 1 can be measured by measuring the distance (pitch) between adjacent inner links 6 in the conveying direction. However, in the conventional elongation measuring device, it is necessary to stop the operation of the conveyor C in order to measure the distance. In contrast, the chain measuring system S according to the present embodiment can measure the wear of the drive chain 1 by measuring the pitch for each inner link 6 while the conveyor C is operating. As a result, the chain measuring system S can measure the wear of the drive chain 1 during the conveyance of the heavy object H. Hereinafter, the configuration and operation of the chain measuring system S will be described in detail.

[0023] <Configuration of Chain Measuring System S> FIG. 3 is a diagram showing the configuration of the chain measurement system S. FIG. 3 is a view of the chain measurement system S seen from above. The chain measurement system S is a system for measuring the wear of the drive chain 1 during the conveyance of the heavy object H, and includes a detection device 10, an imaging device 11, and a measurement device 12. The detection device 10, the imaging device 11, and the measurement device 12 are connected via a network such as a LAN (Local Area Network) or a digital bus such as a USB (Universal Serious Bus).

[0024] The detection device 10 is provided at a position closer to the imaging device 11 on the drive chain 1 side than the imaging device 11 and downstream in the conveyance direction from the imaging device 11, and detects the imaging timing for imaging the drive chain 1 during the conveyance of the heavy object H. The detection device 10 irradiates laser light, for example, toward the left side surface of the drive chain 1 in the conveyance direction and the center position of the drive chain 1 in the height direction. The detection device 10 measures the distance between the detection device 10 and the drive chain 1 based on the time until the irradiated laser light returns to the detection device 10, and detects as the imaging timing the timing when the measured distance is longer than a predetermined distance. The predetermined distance is the distance between the position of the detection device 10 and the position of the drive chain 1, and is, for example, the distance R shown in FIG. 3.

[0025] Specifically, when the laser light passes through the opening (the opening between the adjacent inner links 6) below the upper plate 5a and above the lower plate 5b, the detection device 10 measures a distance larger than the distance R, and detects as the imaging timing the timing when the distance is measured. On the other hand, when the laser light is reflected by the inner link 6 and returns to the detection device 10, the detection device 10 measures the distance R and does not detect as the imaging timing the timing when the distance R is measured.

[0026] That is, the detection device 10 detects the imaging timing at which one of the plurality of outer links 5 arranged on the drive chain 1 during the conveyance of the heavy object H is located in the imaging region of the imaging device 11. By operating in this way, the imaging device 11 can capture an imaging image capable of measuring the distance L (pitch) between the first inner link 6a connected to one end of the outer link 5 and the second inner link 6b connected to the other end.

[0027] Furthermore, the detection device 10 may further detect the imaging timing on the condition that a time when the imaging timing is not detected has elapsed after the time detected as the imaging timing. By operating in this way, the imaging device 11 can image each of the plurality of outer links 5 arranged on the drive chain 1 during the conveyance of the heavy object H once. When the detection device 10 detects the imaging timing, it notifies the imaging device 11 of detection information indicating that the imaging timing has been detected.

[0028] The imaging device 11 is, for example, a camera, and images the drive chain 1 at the time when it acquires the detection information from the detection device 10 to generate an imaging image. When the detection device 10 detects the imaging timing, the imaging device 11 generates an imaging image obtained by imaging the first inner link 6a connected to one end of the outer link 5 and the second inner link 6b connected to the other end of the outer link 5. In FIG. 3, the imaging device 11 images from the left side surface of the drive chain 1 in the conveyance direction, but it may also image from the right side surface of the drive chain 1 in the conveyance direction. The imaging device 11 outputs the generated imaging image to the measuring device 12.

[0029] By the way, the outer link 5, the first inner link 6a, and the second inner link 6b included in the imaging image generated by the imaging device 11 may have unclear contours due to the brightness around the conveyor C, the reflection of the illumination provided around the conveyor C, or external light. Therefore, the imaging device 11 may clarify the contours of the outer link 5, the first inner link 6a, and the second inner link 6b included in the imaging image by imaging the drive chain 1 in a backlight state.

[0030] For example, as shown in FIG. 3, the chain measurement system S further includes an irradiation device 13 that irradiates the drive chain 1 with transmitted light from a direction opposite to the direction in which the imaging device 11 is provided in the drive chain 1. The irradiation device 13 includes a light source 131 for irradiating the drive chain 1 with light by transmitted illumination (so-called backlight), and a transmission screen 132 that transmits the light irradiated by the light source 131. In the chain measurement system S, the light source 131 irradiates the drive chain 1 with light through the transmission screen 132, thereby irradiating the drive chain 1 with transmitted light.

[0031] Then, the imaging device 11 generates a captured image captured in a state where the irradiation device 13 irradiates the drive chain 1 with transmitted light. By operating in this way, the imaging device 11 can generate a captured image with clear contours of the outer link 5, the first inner link 6a, and the second inner link 6b. As a result, it is possible to prevent the measuring device 12 from erroneously measuring the distance L (pitch) between the first inner link 6a and the second inner link 6b. Further, in the measuring device 12, the load of image processing for clarifying the contours of the first inner link 6a and the second inner link 6b included in the captured image can be reduced.

[0032] The measuring device 12 is an information processing terminal such as a mobile phone (including a smartphone), a tablet terminal, or a personal computer, and controls the activation and stop of the detection device 10, the imaging device 11, and the irradiation device 13. Further, the measuring device 12 controls the driving of the first sprocket 14 and the second sprocket 15, which will be described later. The measuring device 12, the irradiation device 13, the first sprocket 14, and the second sprocket are connected via a network such as a LAN or a digital bus such as USB.

[0033] The measuring device 12 measures the wear of the drive chain 1 based on the distance L between the first inner link 6a and the second inner link 6b included in the captured image. For example, the measuring device 12 identifies the distance L (pitch) between the first inner link 6a and the second inner link 6b included in the captured image, and measures whether the identified pitch is equal to or greater than a threshold value. The threshold value is, for example, a predetermined ratio of the pitch (so-called, rated value) at the time of manufacturing the drive chain 1. The predetermined ratio is, for example, 105%. By operating in this way, the measuring device 12 can measure the wear of the plurality of inner links 6 and the plurality of pins 7 arranged on the drive chain 1 even when the drive chain 1 is carrying a heavy object H.

[0034] In the chain measurement system S, it is desirable to be able to identify the worn inner links 6 among the plurality of inner links 6 arranged on the drive chain 1. Therefore, the measuring device 12 may identify the link identification number (hereinafter referred to as "link ID") of each inner link 6, and cause a display device (not shown) to display the link ID and the pitch for each inner link 6. In this case, the measuring device 12, for example, associates the link ID and the pitch of the first inner link 6a and causes them to be displayed on the display device. Note that the measuring device 12 may identify the link ID of each outer link 5, and cause the display device to display the pitch and the link ID between the inner links 6 connected to the outer link 5 for each outer link 5.

[0035] For example, the conveyor C includes a drive chain 1 including at least one of the plurality of outer links 5 and inner links 6 to which an identification code for identifying the link is attached. The identification code is a code that can be extracted from the captured image generated by the imaging device 11, and is, for example, a mark such as a symbol, a sign, or a character attached using a film or paint such as a seal. In the following description, it is assumed that the conveyor C includes a drive chain 1 to which an identification code is attached to one inner link 6.

[0036] The measuring device 12 identifies the link ID of at least one of the outer link 5 and the inner link 6 based on the identification code included in the captured image. For example, when the measuring device 12 extracts the identification code from the first inner link 6a included in the captured image, it identifies the link ID of the first inner link 6a as "1". That is, the measuring device 12 identifies the link ID of the first inner link 6a with the identification code as "1". Then, every time the measuring device 12 acquires a captured image from the imaging device 11, it generates a new link ID by adding 1 to the link ID identified before acquiring the captured image, and identifies the link ID of the first inner link 6a included in the captured image as the new link ID.

[0037] The measuring device 12 causes the display device to display, in association with the link ID, the wear of the drive chain 1 based on, for example, the distance (pitch) between the first inner link 6a and the second inner link 6b. The wear of the drive chain 1 is, for example, the difference between the pitch (rated value) at the time of manufacture and the measured pitch, but the measured pitch may also be displayed.

[0038] FIG. 4 shows an example of the measurement result of the wear displayed on the display device. The horizontal axis in FIG. 4 indicates the link ID, and the vertical axis in FIG. 4 indicates the pitch. In FIG. 4, the pitch D at the time of manufacture of the drive chain 1 and the pitch threshold value T are shown. In FIG. 4, since the pitch P of the first inner link 6a and the second inner link 6b corresponding to the link ID "N" is equal to or greater than the threshold value T, the administrator of the conveyor C can identify that the drive chain 1 is worn and that the inner link 6 corresponding to the link ID "N" is worn. By causing the measuring device 12 to display on the display device in this way, the measuring device 12 can notify the administrator of the conveyor C of the inner link 6 in which wear has occurred in the drive chain 1.

[0039] Incidentally, since the tension of the drive chain 1 during the conveyance of the heavy object H varies according to the weight of the heavy object H, the drive chain 1 may include inner links 6 that move with an appropriate tension and inner links 6 that move with a tension smaller than the appropriate tension. In the inner link 6 that moves with a tension smaller than the appropriate tension, the chain slackens (so-called sagging) occurs, resulting in a problem that the correct pitch cannot be measured. Therefore, the chain measurement system S further includes a power transmission member for applying tension to the outer link 5 and the inner link 6 that are moving the imaging area among the plurality of outer links 5 and inner links 6 included in the drive chain 1.

[0040] As shown in FIG. 3, the chain measurement system S further includes a first power transmission member 14 disposed in front of the imaging area and a second power transmission member 15 disposed behind the imaging area in the conveyance direction for conveying the heavy object H. The first power transmission member 14 and the second power transmission member 15 are, for example, sprockets. In the following description, the first power transmission member 14 is referred to as the first sprocket 14, and the second power transmission member 15 is referred to as the second sprocket 15.

[0041] FIG. 5 is a view showing the first sprocket 14 and the second sprocket 15. FIG. 5 is a side view of the chain measurement system S. A plurality of convex portions Z that fit into the central hole K of the annular inner link 6 are formed on the first sprocket 14 and the second sprocket 15. The first sprocket 14 and the second sprocket 15 apply tension to the outer link 5 and the inner link 6 that are moving the imaging area A by rotating with one of the plurality of formed convex portions Z fitted into the hole K.

[0042] By operating the first sprocket 14 and the second sprocket 15 as described above, the chain measurement system S can prevent applying tension in front of the position B of the drive chain 1 in the conveying direction. As a result, the chain measurement system S can prevent slack from occurring in the drive chain 1 due to the tension applied to the drive chain 1 for measuring the pitch in front of the chain measurement system S in the conveying direction.

[0043] As shown in FIG. 5, the first sprocket 14 and the second sprocket 15 rotate in the conveying direction. When the first sprocket 14 and the second sprocket 15 rotate in the conveying direction, the tension acting on the drive chain 1 by the first sprocket 14 is greater than the tension acting on the drive chain 1 by the second sprocket 15.

[0044] The first sprocket 14 has, for example, a motor 16 for increasing the rotation speed of the first sprocket 14. By the measuring device 12 driving the motor 16, a tension acting behind the position B of the drive chain 1 in the conveying direction is generated. On the other hand, the second sprocket 15 has, for example, a brake 17 for reducing the rotation speed of the second sprocket 15. By the measuring device 12 driving the brake 17, the tension acting on the drive chain 1 is made smaller than the tension generated by the first sprocket 14.

[0045] By operating as described above, the first sprocket 14 and the second sprocket 15 can apply tension with a small power behind the position B of the drive chain 1 and in front of the position E of the drive chain 1 in the conveying direction. And since the first sprocket 14 and the second sprocket 15 can apply tension to the outer link 5 and the inner link 6 moving in the imaging region A, the measuring device 12 can measure the correct pitch based on the imaging image of the drive chain 1 in which no slack has occurred.

[0046] Furthermore, in the chain measurement system S, one of the first sprocket 14 and the second sprocket 15 has the convex portion Z fitting into the hole portion K on the first surface of the peripheral surface in the longitudinal direction of the drive chain 1, and the other has the convex portion Z fitting into the hole portion K on the second surface opposite to the first surface of the peripheral surface. Specifically, when the first surface is the upper surface in the longitudinal direction, the second surface is the lower surface in the longitudinal direction, and when the first surface is the left side surface in the conveying direction, the second surface is the right side surface in the conveying direction.

[0047] As an example, in FIG. 5, the first sprocket 14 has the convex portion Z fitting into the hole portion K on the lower surface in the longitudinal direction of the drive chain 1, and the second sprocket 15 has the convex portion Z fitting into the hole portion K on the upper surface in the longitudinal direction of the drive chain 1. By being configured as described above, the force acting on the drive chain 1 by the second sprocket 15 can be directed in a direction opposite to the direction of the force acting on the drive chain 1 by the first sprocket 14 in a direction orthogonal to the conveying direction. As a result, it is possible to prevent the drive chain 1 from moving (so-called, shifting) in a direction orthogonal to the conveying direction.

[0048] <Processing sequence in the chain measurement system S> FIG. 6 is a diagram showing an example of a processing sequence in the chain measurement system S. The processing sequence shown in FIG. 6 is a processing sequence showing an operation in which the chain measurement system S measures the wear of the drive chain 1 and causes the display device to display the measurement result.

[0049] The measuring device 12 starts the rotation of the first sprocket 14 and the second sprocket 15 by driving the motor 16 and the brake 17 (S11). The measuring device 12 starts the irradiation of transmitted light to the irradiation device 13 by activating the irradiation device 13 (S12). After activating the imaging device 11, the measuring device 12 activates the detection device 10 and starts the detection of the imaging timing by the detection device 10 (S13).

[0050] When the detection device 10 has not detected the imaging timing (NO in S14), it repeats the detection of the imaging timing. When the detection device 10 detects the imaging timing (YES in S14), the imaging device 11 generates an imaging image of the outer link 5 included in the imaging region A (S15) and outputs it to the measuring device 12.

[0051] The measuring device 12 identifies the link ID of the first inner link 6a connected to the outer link 5 included in the imaging image (S16). The measuring device 12 measures the distance (pitch) between the first inner link 6a and the second inner link 6b connected to the outer link 5 included in the imaging image (S17). When the measured pitch is equal to or greater than the threshold value (YES in S18), the measuring device 12 determines that the inner link 6 and the pin 7 are worn (S19). When the measured pitch is less than the threshold value (NO in S18), the measuring device 12 determines that the inner link 6 and the pin 7 are not worn (S20).

[0052] When the measuring device 12 has measured all the inner links 6 arranged on the drive chain 1 (YES in S21), the measuring device 12 causes the display device to display the measurement results indicating the link ID and pitch of each first inner link 6a (S22), and ends the process. When there is an inner link 6 that the measuring device 12 has not measured (NO in S21), the chain measurement system S repeats the operations from step S14 to step S20.

[0053] <Effect of the chain measurement system S> As described above, the chain measurement system S includes a detection device 10 that detects the imaging timing for imaging the drive chain 1 during transportation of the heavy object H, in which the annular outer links 5 and inner links 6 are alternately arranged in the longitudinal direction and the outer links 5 and inner links 6 are connected by pins 7; an imaging device 11 that generates an imaging image by imaging the first inner link 6a connected to one end of the outer link 5 and the second inner link 6b connected to the other end of the outer link 5 when detecting the imaging timing at which one outer link 5 is located in the imaging region; and a measuring device 12 that measures the wear of the drive chain 1 based on the distance between the first inner link 6a and the second inner link 6b included in the imaging image.

[0054] Since the chain measurement system S is configured in this way, the measuring device 12 can measure the distance (pitch) between the inner links 6 connected to the outer link 5 from the captured image of the outer link 5 generated by the imaging device 11 while the drive chain 1 for transporting the heavy object H is in operation. Then, by calculating the difference between the measured pitch and the pitch at the time of manufacture by the measuring device 12, the wear of the drive chain 1 during operation can be measured.

[0055] Further, by generating a captured image for each outer link 5 arranged on the drive chain 1 by the imaging device 11, the measuring device 12 can measure the wear of the pin 7 connecting the inner link 6 and the outer link 5 and the inner link 6 for each inner link 6 arranged on the drive chain 1. That is, the measuring device 12 can identify the worn pin 7 and inner link 6. Furthermore, since the first sprocket 14 and the second sprocket 15 rotate in the transport direction, the measuring device 12 can measure in a state where no sag occurs in the inner link 6 and the outer link 5 to be measured. Therefore, the measuring device 12 can measure the wear of the drive chain 1 with high accuracy.

[0056] As described above, the present invention has been described using embodiments. However, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist. For example, all or part of the device can be configured by being functionally or physically dispersed and integrated in an arbitrary unit. Also, new embodiments generated by any combination of a plurality of embodiments are included in the embodiments of the present invention. The effects of the new embodiments generated by the combination have the effects of the original embodiments combined.

Explanation of Reference Numerals

[0057] C Conveyor S Chain Measurement System 1 Drive Chain 2 Free Rail 3 Free Trolley 3a Front Free Trolley 3b Rear Free Trolley 4 Carrier 5 External Link 5a Upper Plate 5b Lower Plate 6 Internal Link 6a First Internal Link 6b Second Internal Link 7 Pin 7a First Pin 7b Second Pin 8 Pusher 9 Dog 10 Detection Device 11 Imaging Device 12 Measuring Device 13 Irradiation Device 131 Light Source 132 Transmission Screen 14 First Power Transmission Member 14 First Sprocket 15 Second Power Transmission Member 15 Second Sprocket 16 Motor 17 Brake K Hole Portion Z Protrusion

Claims

1. A detecting device for detecting an imaging timing for imaging a chain during conveyance of a heavy object, wherein annular outer links and inner links are alternately arranged in the longitudinal direction and the outer links and the inner links are connected by pins; An imaging device that generates an imaging image by imaging a first inner link connected to one end of the outer link and a second inner link connected to the other end of the outer link when detecting the imaging timing at which one of the outer links is located in an imaging area; A measuring device that measures wear of the chain based on a distance between the first inner link and the second inner link included in the imaging image; A chain measurement system comprising the above.

2. Further comprising a first power transmission member disposed in front of the imaging area and a second power transmission member disposed behind the imaging area in a conveyance direction for conveying the heavy object, wherein a plurality of convex portions that fit into hole portions of the inner links are formed on the first power transmission member and the second power transmission member; The chain measurement system according to Claim 1.

3. One of the first power transmission member and the second power transmission member has the convex portion fitting into the hole portion on a first surface of a peripheral surface of the chain in the longitudinal direction, and the other has the convex portion fitting into the hole portion on a second surface opposite to the first surface of the peripheral surface; The chain measurement system according to Claim 2.

4. When the first power transmission member and the second power transmission member rotate in the conveyance direction, a tension applied to the chain by the first power transmission member is greater than a tension applied to the chain by the second power transmission member; The chain measurement system according to Claim 2 or 3.

5. Further comprising an irradiation device that irradiates the chain with transmitted light from a direction opposite to a direction in which the imaging device is provided on the chain, wherein the imaging device generates the imaging image by imaging in a state where the irradiation device irradiates the chain with transmitted light; The chain measurement system according to Claim 1.

6. The detecting device measures a distance between the detecting device and the chain, and detects, as the imaging timing, a timing at which the measured distance is longer than a predetermined distance; The chain measurement system according to Claim 1.

7. The chain includes at least one of one or more of the outer links and the inner links to which an identification code for identifying a link is attached. The measurement device identifies the identification number of at least one of the outer link and the inner link based on the identification code included in the captured image. The chain measurement system according to claim 1. **Claim 8** The measurement device causes the display device to display the wear of the chain based on the distance between the first inner link and the second inner link, in association with the identification number. The chain measurement system according to claim 7. **Claim 9** The chain includes a pusher for pushing a trolley that supports the heavy object in a transport direction for transporting the heavy object. The chain measurement system according to claim 1.

Images