JP2017167132A - Elongation measurement device and elongation measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elongation measurement device capable of accurately detecting a wear elongation of a chain by making an elongation device traveling on a link chain at the drive stopping time of the link chain.SOLUTION: An elongation measurement device is attached with a pair of main wheels, an auxiliary wheel mounted between the pair of main wheels; a laser range finder mounted between the pair of main wheels with a detection direction downwardly oriented; and an internal calculation part for calculating a distance between the adjacent inner links based on a detection value of the laser range finder and the detection value of an encoder. The distance between a main axis of the front main wheel and the auxiliary wheel is defined as L1, the distance between the laser beam output of the laser range finder and the front main wheel is defined as L2, and the distance between the rear main wheel and the auxiliary wheel is defined as L3. L1, L2, and L3 are set so that the pair of main wheels is located in an abutting effective range of each of inner link in a state that the distance between the adjacent inner links is measured.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a technique for measuring elongation between links of a link chain when the link chain is stopped.

  In a production line for various products, a semi-finished product or a final product is often continuously conveyed by a link chain conveyor arranged in the line. The link chain conveyor normally has a structure in which an endless loop link chain is spanned between two sprocket wheels, and an ascending link chain portion is supported by, for example, a slide rail having a smooth surface.

In general, such a link chain conveyor rotates and drives only a sprocket located on the downstream side in the conveying direction as a driving wheel, and continuously conveys an object to be conveyed placed on the link chain portion on the ascending side. .
At this time, the link chain in operation is repeatedly bent with the tensile force applied by the sprocket, so that the connecting portion of the link wears down, and the connecting pin is reduced in diameter and connected to the inner and outer links. As the diameter of the pin mounting hole increases, wear elongation occurs in the link chain.

This wear elongation increases as the operating time becomes longer, but if the wear elongation exceeds a certain amount, not only smooth transfer by the link chain conveyor is not possible, but in the case of significant damage, the link chain breaks. There is a risk that productivity will be reduced.
Therefore, it is necessary to quantitatively measure the wear elongation of the link chain.
Here, there are two methods for measuring the wear elongation: a method of measuring while the link chain conveyor is operating, and a method of measuring while the link chain conveyor is stopped.

  Of the two methods, the method of measuring during operation assumes that a measuring device is permanently installed and continuously measured for each device of the link chain conveyor. For this reason, there is a problem in terms of cost, such as securing the number of measurement devices prepared. On the other hand, in the method of measuring during the stoppage, it is possible to bring in the measurement device every time using the time when the target equipment is stopped for maintenance, etc., so prepare a large number of measurement devices There is no need, and there is a great merit in terms of cost.

As a measuring method of the wear elongation amount of the link chain, there are measuring methods described in Patent Documents 1 to 3, for example.
The measuring method described in Patent Document 1 is a measuring method during operation of the equipment, in which a non-contact type laser displacement meter is disposed and the distance to the upper surface of the link chain is continuously measured. However, the measurement method described in Patent Document 1 only presents a measurement method during operation of the equipment, and no consideration is given to a method for performing measurement with high accuracy by manually running the measurement device when the equipment is stopped. Not.

  In the measuring method described in Patent Document 2, two non-contact eddy current displacement sensors are arranged toward the side surface or upper surface of the link chain, and the non-contact eddy current displacement sensor is used to separate the link chain to the side surface or upper surface. In this method, the distance is continuously measured and the wear elongation between the chain links is obtained from the measurement result. In this method, it is estimated that the wear elongation of the link chain can be measured while the equipment is stopped. However, as a fundamental measurement accuracy, the displacement sensor is an eddy current displacement sensor, and this eddy current displacement sensor has a wide sensor spot as shown in FIG. 9 and FIG. The curved part of the link piece cannot be detected accurately. For this reason, since there is no measurement accuracy required to measure the wear elongation between the chain links, there is a disadvantage that the wear elongation between the chain links cannot be measured accurately and cannot be put to practical use. In addition, no consideration is given to measurement while traveling on a link chain.

  In addition, the measurement method described in Patent Document 3 is a method using a cart type measurement jig in which a pair of small-diameter sprocket wheels are rotatably attached to both ends of a connecting bar. That is, the pair of small-diameter sprocket wheels are moved to engage with the link chain to be measured, and the rotational angle difference between the small-diameter sprocket wheels during this movement is measured. Ask for. In this method, it is estimated that the wear elongation of the link chain can be measured while the equipment is stopped. However, it has the disadvantage that it can not be used practically because it can not accurately measure the amount of wear elongation between chain links by picking up the step generated in the link connecting part caused by the wear elongation of the outer link and inner link of the link chain. Yes. In other words, the level difference caused by wear is not taken into consideration.

  In addition, while various inventions relating to link chain elongation measuring devices have been devised, no method has been devised that can stably move on a link chain where a level difference has occurred and measure accurately when the equipment is stopped.

JP-A-11-325829 JP-A-2-130402 JP-A-8-327320

  The present invention focuses on the above points, and an object of the present invention is to accurately detect the wear elongation of a chain by causing an elongation measuring device to travel on the link chain when the link chain is stopped.

  The inventors of the present invention have studied a device for detecting the wear and elongation of the chain while running the wheel on a stopped link chain by rolling the wheel. In the chain portion extending in the direction, a step is generated in the connecting portion between the outer link and the inner link, and it has been found that the measurement method such as Patent Document 3 deteriorates the measurement accuracy.

The present invention has been made based on the above findings.
That is, in order to solve the problem, one aspect of the present invention is an elongation measuring device that detects the elongation of a link chain formed by alternately connecting outer links and inner links,
A frame disposed along the extending direction of the chain, a pair of main wheels attached to the frame apart from each other, an auxiliary wheel attached to the frame between the pair of main wheels, and the pair of main wheels A laser distance meter attached to the frame between the wheels and having a detection direction directed downward; an encoder supported by the frame and detecting rotation of one of the pair of main wheels; and the laser An interval calculation unit that calculates a distance between adjacent inner links based on a detection value of the distance meter and a detection value of the encoder, and
In the top view, the position between the pair of chain pin centers in each inner link is defined as the effective contact range, the distance between the one main shaft and the auxiliary wheel is L1, and the laser distance meter in the top view. When the distance between the laser beam output portion and the axle of the one main wheel is L2, and the distance between the other main wheel of the pair of main wheels and the auxiliary wheel is L3,
In a state in which the distance between adjacent inner links is being measured, the distances L1, L2, and L3 are set so that a pair of main wheels are positioned in the effective contact range of different inner links.

  According to one aspect of the present invention, even when wear occurs in the chain connecting portion and a step is generated between the outer link and the inner link due to the influence of gravity, the step caused by the wear is caused when the link chain is stopped. It is possible to accurately detect the wear elongation of the chain while suppressing disturbance.

It is a schematic diagram which shows the connection of a link chain, (a) is a side view, (b) is a top view. It is a figure which shows the winding of the link chain to a sprocket. It is explanatory drawing of the mechanism in which the inner link of a link chain wears. It is explanatory drawing of the mechanism in which the inner link of a link chain wears. It is explanatory drawing of the mechanism in which the inner link of a link chain wears. It is a side view explaining the inner link floating phenomenon when the connecting pin mounting hole of the inner link is worn and tension is applied. It is a schematic diagram which shows the relationship between a link chain conveyor and an elongation measuring apparatus. It is a figure which shows the elongation measuring apparatus which concerns on embodiment based on this invention, (a) shows the state of a measurement start position, (b) shows the detected value of a laser range finder. It is a figure which shows the structure of a calculating part. It is a figure which shows the elongation measuring apparatus based on embodiment based on this invention, (a) shows the state of the position immediately before completion of a measurement, (b) shows the detected value of a laser distance meter, (c) is the detection of an encoder. Signals are shown. It is a figure which shows the relationship between a chain pitch and a measurement range. It is a figure explaining a state when elongation generate | occur | produces between each link.

  As described above, the link chain elongation measurement using the elongation measuring device is not necessarily performed while the link chain is in operation, and the measurement is often performed with a portable measuring device attached. In that case, install a measuring device while the line is stopped, operate the link chain, and measure the chain elongation. At this time, the measurement is performed in the procedure of device installation, chain operation, and device removal. However, when a large number of link chains are provided, it is necessary to repeat the work.

Also, when measuring the elongation by driving the link chain, it is necessary to repeat the work of setting the conditions when the measurer approaches the device and releasing the condition after installing the device in consideration of the safety of the measurer. There is a problem that it takes a lot of time constraints and labor.
In addition, in the method of installing and measuring a measuring device for each facility, it is only necessary to measure while the chain is driving, so it is possible to install the device in a place where the chain runout width near the sprocket or guide roller where stable measurement is possible is small. is there.

However, when measurement is performed on a stopped link chain, it is necessary to perform measurement while moving the measurement device (sensor) on the link chain. For this reason, it is preferable that the elongation measuring device has a stable measuring mechanism that can pass through the step portion between the outer link and the inner link caused by wear and can stably move on the chain.
Next, a mechanism for creating a step between the outer link 11 and the inner link 10 due to wear will be described.

As shown in FIG. 1, in the link chain 1, the inner links 10 and the outer links 11 are alternately arranged, and the adjacent connecting pin mounting holes 13 at the ends of the inner links 10 and the ends of the outer links 11 are connected. A pin mounting hole 13 is connected by a connecting pin 12.
As shown in FIG. 2, the link chain 1 is connected to the sprocket 3 so that the teeth 3 a of the sprocket 3 enter the space between the two plate plates 11 a constituting the outer link 11 (see FIG. 1B). The link chain 1 is operated by being wound around the outer periphery of the motor 4 and rotationally driving the sprocket 3 on the driving side.

  At this time, as shown in FIG. 2, the link chain 1 in operation is repeatedly bent in a state where the tensile force from the sprocket 3 is applied, so that the connecting portion is worn and the diameter of the connecting pin 12 is reduced. As a result of the increase in the diameter of the connecting pin mounting hole 13 provided in the inner and outer links 10 and 11, wear elongation occurs in the link chain 1 by the amount corresponding to the wear.

As shown in FIG. 2, the wear of the above-mentioned connecting portion occurs when the sprocket 3 is wound and when it is wound. Therefore, as shown in FIGS. 3 and 4, the adjacent outer link 11 and inner link 10 are predetermined. It is generated by the force applied in the state bent at the angle of. For this reason, when the connecting portion is worn, the diameter of the connecting pin 12 and the diameter of the connecting pin mounting hole 13 provided in the inner and outer links 10 and 11 are increased. At this time, the wear portion (the portion where the space is formed) is formed in the inner link 10 so as to go obliquely downward and outward of the connecting portion as shown in FIG. In this way, when wear occurs and elongation occurs, the greater the wear, the more the tension is applied to the link chain 1, and the phenomenon that the inner link 10 is lifted with respect to the outer link 11 as shown in FIG. A step D is generated between the outer link 11 and the inner link 10.
The present invention has been made with such knowledge, and an object thereof is to make it possible to accurately measure elongation even when the inner link 10 is lifted due to wear.

(Constitution)
As shown in FIG. 7, the elongation measuring device SW of the present embodiment is arranged on an ascending side link chain 1 </ b> A extending in the horizontal direction such as the horizontal direction, among the link chains 1 arranged in an endless ring shape of the link chain conveyor. Placed on. And the state of wear elongation of the link chain 1 is measured by manually running the elongation measuring device SW along the link chain 1 located on the ascending side. Reference numeral 5 denotes a slide rail.
As shown in FIG. 8, the elongation measuring device SW of the present embodiment includes a frame 20, a pair of main wheels 21 and 22 (a front main wheel 21 and a rear main wheel 22), and a pair of main wheels 21 and 22. The auxiliary wheel 23, the encoder 25, the laser distance meter 24, and the calculating part 26 which are arrange | positioned among are provided.

<Frame 20>
The frame 20 is a long (long axis) frame that can extend along the chain extending direction.
<Main wheels 21, 22>
The pair of main wheels 21 and 22 are attached to the front side and the rear side of the frame 20 so as to be able to roll in the longitudinal direction of the frame 20 (the axial direction of the frame 20).
The distance L0 between the pair of main wheels 21 and 22 is set to a length longer than twice the chain pitch CP.

<Encoder 25>
The encoder 25 is provided on one of the pair of main wheels 21 and 22 and outputs a signal each time the corresponding main wheels 21 and 22 rotate by a predetermined rotation angle. In the present embodiment, the encoder 25 is set to detect the rotational speed on the front main wheel 21 side. The encoder 25 may be set so as to detect the rotational speed on the rear main wheel 22 side, or may detect the rotational speed of both the main wheels 21 and 22. When detecting the rotational speeds of both main wheels 21 and 22, the distances L1, L2, and L3 described later may be obtained by setting one of the main wheels 21 and 22 as the encoder setting side.

<Auxiliary wheel 23>
The auxiliary wheel 23 is attached to the frame 20 between the pair of main wheels 21 and 22 so as to roll in the longitudinal direction of the frame 20 (the axial direction of the frame 20).
The axles of the pair of main wheels 21 and 22 and the auxiliary wheel 23 are arranged in parallel to each other and can roll in the same direction, and the lower end positions of the pair of main wheels 21 and 22 and the auxiliary wheel 23. It is preferable that the lower end position is set so as to be on the same plane.

  In the present embodiment, the position of the auxiliary wheel 23 is set such that the inter-axis distance L3 between the rear main wheel 22 and the auxiliary wheel 23 is equal to the chain pitch CP. However, the inter-axis distance L2 between the front main wheel 21 and the auxiliary wheel 23 is preferably less than 1.5 times the chain pitch CP so that the auxiliary wheel 23 does not approach the rear main wheel 22 too much. Accordingly, the auxiliary wheel 23 is disposed at a position closer to the laser optical axis 24 b of the laser rangefinder 24 than the pair of main wheels 21 and 22.

<Laser rangefinder 24>
The laser rangefinder 24 is attached to the frame 20 between the pair of main wheels 21 and 22 and has a detection direction directed downward. In the present embodiment, the laser optical axis 24 b generated from the output unit 24 a of the laser distance meter 24 is set in a downward direction orthogonal to the moving direction of the frame 20. The laser rangefinder 24 outputs laser light downward and detects the distance to the opposing object based on the reflected light. Note that there is no problem even if the laser optical axis 24b is slightly inclined.
Here, when the elongation measuring device SW according to the present embodiment is manually traveled, a virtual axis X (FIG. 1B) in which the laser light emitted from the laser distance meter 24 passes through the central axis of the upper surface of each inner link 10. ) See) Drive as you move up. In other words, it is assumed that the apparatus is manually driven so that the laser distance meter 24 is positioned at the center in the width direction of the chain link as viewed from above.

<About the distance between axes>
As shown in FIG. 11, the position between the pair of chain pin centers in each inner link 10 in the top view is defined as a contact effective range MR. Further, a distance from the center of the chain pin before wear (the center of the connecting pin mounting hole) to the end portion in the longitudinal direction of the link is defined as x ′. As can be seen from FIG. 11, in the side view, the upper portion of the inner link 10 has a linear contour in the effective contact range MR, but the link length closer to the chain pin center (the center of the connecting pin mounting hole). At the direction end, it has a contour drawn in an arc toward the lower side.

  When chain elongation occurs between the links due to wear as shown in FIG. 12, the distance between the adjacent inner links 10 is widened by twice the chain elongation. In the present embodiment, the limit amount of chain elongation allowed between links in a top view is defined as x. That is, maintenance inspection is performed so that the link chain is used such that the distance between the adjacent inner links 10 is less than twice x.

Further, as shown in FIG. 8, the inter-axis distance between the front main wheel 21 (one main shaft) provided with the encoder 25 and the auxiliary wheel 23 is L1, and the laser beam output unit of the laser rangefinder 24 in a top view The distance between the front main wheel 21 and the axle is defined as L2, and the distance between the rear main wheel 22 (the other main wheel) and the auxiliary wheel 23 of the pair of main wheels 21 and 22 is defined as L3.
In a state where the distance between the adjacent inner links 10 is measured, that is, in a state where the laser light from the laser rangefinder 24 is located in the space between the adjacent inner links 10, the pair of main wheels 21, 22 are The distances L1, L2, and L3 are set so as to be positioned in the effective contact range MR of the different inner links 10, respectively.

  In particular, in a state in which the distance between the adjacent inner links 10 is measured, as shown in FIG. 8, the pair of main wheels 21 and 22 are within the effective contact range MR of any one of the adjacent inner links 10. It is preferable to set the distances L1, L2, and L3 so as to be positioned. In this case, the inter-axis distance L1 is set based on the chain pitch, x and x ′, the distance L2 is set based on the chain pitch and x ′, and the inter-axis distance L3 is set equal to the chain pitch. To do.

For example, the distances L1, L2, and L3 may be set so as to satisfy the following expressions (1) to (4).
CP + 2 · x ≦ L1 <CP + x ′ (1)
CP ≦ L2 <CP + x ′ (2)
L1 ≧ L2 (3)
L3 = CP (4)
Here, CP is a chain pitch.

<Calculation unit 26>
The calculation unit 26 calculates the elongation based on the distance information detected by the laser distance meter 24 and the pulse signal from the encoder 25. As shown in FIG. 9, the calculation unit 26 includes an interval calculation unit 26A and an elongation amount calculation unit 26B.
The interval calculation unit 26 </ b> A performs a process of calculating the distance between the adjacent inner links 10 based on the detection value of the laser distance meter 24 and the detection signal of the encoder 25.

  Specifically, the interval calculation unit 26A detects that the distance detected by the laser distance meter 24 is equal to or greater than the set distance until the distance detected by the laser distance meter 24 becomes less than the set distance. Based on the detection signal of the encoder 25, the distance between adjacent inner links 10 is calculated. When the distance calculation unit 26A calculates the distance between the adjacent inner links 10, the interval calculation unit 26A supplies the calculated value to the elongation amount calculation unit 26B.

The set distance is set to, for example, 1.5 times or more the detection distance in a state where the laser rangefinder 24 is positioned on the position of the inner link 10.
As shown in FIG. 1B, in the direction along the extending direction of the inner links 10, the space between the adjacent inner links 10 is a space portion between the plate members of the outer links 11 facing in the width direction. For this reason, when the distance is measured by the laser distance meter 24 after moving in the direction along the inner link 10, the distance by the laser distance meter 24 suddenly increases at the position shown in FIG. Immediately after the position shown in FIG. 10, the other end of the next inner link 10 is detected, and the distance by the laser rangefinder 24 suddenly decreases. Thus, the range in which the distance by the laser rangefinder 24 is equal to or greater than the set distance is the measurement range SR between the adjacent inner links 10 (see FIG. 11). The distance between the adjacent inner links 10 is multiplied by the number of pulse signals from the encoder 25 detected when moving between the adjacent inner links 10, that is, by multiplying the number of pulses detected by the encoder 25 by the set value. Can be calculated. Here, when the encoders 25 are provided on both the pair of main wheels 21 and 22 for detection, for example, an average value of each distance obtained by the encoders 25 may be adopted.

The elongation amount calculation unit 26B calculates the difference between the distance between the inner links 10 calculated by the interval calculation unit 26A and the reference length of the chain pitch CP (chain pitch before wear) of the link chain 1 between the inner links 10 measured. Calculated as the elongation amount 2 · Δx.
The elongation amount calculation unit 26B stores the calculated elongation amount in the storage unit or displays it on the display unit.
The elongation measurement may be performed by intermittently moving the chain conveyor slightly and changing the portion of the link chain 1A located on the ascending side.

(Operation other)
It is assumed that the inner link 10 is lifted due to wear, and a step D is generated between the inner link 10 and the outer link 11.
At this time, assuming that the long frame 20 is supported by only two wheels and an apparatus provided with an encoder on one of the wheels is run on the link chain 1, the distance between the axles of the two wheels is When it is too short, the wheel provided with the encoder 25 during measurement passes through the step D, so that disturbance is input to the detected value of the encoder. On the other hand, even if the distance between the axles of the two wheels is too long, the wheel provided with the encoder during measurement passes through the step D, so that disturbance is input to the detected value of the encoder.

  On the other hand, in the case of the elongation measuring device SW of the present embodiment, the distance between the main shafts of the pair of main wheels 21 and 22 is made longer than twice the chain pitch CP, and the distance between the adjacent inner links 10 is set. During measurement, the distances L1, L2, and L3 are dimensioned so that the pair of main wheels 21 and 22 are positioned within the effective contact range MR of the inner link 10, respectively. The distance between the ends of the front and rear inner link 10 can be accurately measured without being affected by the step D (disturbance) generated between the front and rear links 10.

Hereinafter, the case where the encoder 25 is provided in the front main wheel 21 will be described. The same applies to the case where the encoder 25 is provided on the rear main wheel 22, and the description thereof is omitted.
As shown in FIG. 8, it is assumed that the elongation measuring device SW is manually traveled on the ascending side link chain 1A from the left side to the right side.
The position of the outer link 11 is relatively displaced downward when wear occurs.

Further, the distance (measurement range SR) between the adjacent inner links 10 is increased by the chain elongation amount 2 · Δx (<(2 · x)) due to wear. However, as shown in FIG. 11, the measurement range SR is a gap between the inner links 10, and thus is smaller than the link length of the outer links 11. That is, the measurement range SR is shorter than the chain pitch CP.
On the other hand, since the distance L2 between the axle of the front main wheel 21 and the laser optical axis 24b is set so as to satisfy the expression (2), the front main wheel at the start of measurement as shown in FIG. 21 is already located on the contact effective range MR of the front inner link 10. For this reason, since the measurement has not yet started when the front main wheel 21 passes through the step D, no disturbance to the measurement occurs.

  Further, the inter-axis distance L3 between the rear main wheel 22 and the auxiliary wheel 23 is set to the chain pitch CP, and the inter-axis distance L1 between the front main wheel 21 and the auxiliary wheel 23 is set to 2 · x more than the chain pitch CP. The length is set longer by ~ x '. For this reason, after the laser rangefinder 24 approaches the next measurement range SR, at least one of the auxiliary wheel 23 and the rear wheel contacts the rear inner link 10 until the state shown in FIG. By being located on the contact effective range MR, the auxiliary wheel 23 and the rear wheel are not disturbed by the step D immediately before the start of measurement. Further, when the measurement is started in the state of FIG. 8, the distance L0 between the pair of main wheels 21 and 22 is set to a length longer by 2 · x to x ′ than the chain pitch CP. The measurement starts from the state in which the main wheels 21 and 22 are both on the effective contact range MR of the front and rear inner links 10.

  Further, the auxiliary wheel 23 floats as shown in FIG. 10 during the measurement, but the front and rear main wheels 21 and 22 are positioned on the contact effective range MR of the inner link 10, thereby Not affected. At the end of the measurement, the auxiliary wheel 23 is in a floating state with respect to the laser optical axis 24b of the laser distance meter 24, and the auxiliary wheel 23 rides on the contact effective range MR of the inner link 10 after the measurement ends. No disturbance due to the step D is input during measurement.

As described above, in this embodiment, even if a floating phenomenon occurs in the inner link 10 due to wear, the influence of disturbance due to the step D between the inner link 10 and the outer link 11 is not affected. It can be detected well.
Here, although the case where the frame 20 travels toward the front main wheel 21 is described, the frame 20 travels toward the rear main wheel 22 side, that is, travels from right to left in FIG. Even in the case of the expansion, the elongation can be detected accurately without being affected by the step D.

  The reason for this will be described. At the start of measurement, as shown in FIG. 8, the auxiliary wheel 23 has already been positioned and floated on the outer link 11, and the front and rear main wheels 21, 22 are respectively inward. Since it is on the effective contact range MR of the link 10, there is no influence of the step D. In addition, as shown in FIG. 10, the auxiliary wheel 23 rides on the inner link 10 before the measurement is completed, but the front and rear main wheels 21 and 22 are both placed on the link. The impact due to riding is small, and there is no or little influence on the main wheels 21 and 22 provided with the encoder 25. Thus, the elongation can be detected with high accuracy.

Further, even when the auxiliary wheel 23 is disposed close to the center of the front and rear main wheels 21 and 22, the elongation can be accurately detected without being affected by the step D.
That is, at the start of measurement, the auxiliary wheel 23 is in a floating state, but the front and rear main wheels 21 and 22 are respectively placed on the effective contact range MR of the inner link 10, and thus there is no influence of the step D. . Further, at the end of the measurement, the auxiliary wheel 23 is still in a floating state, but the front and rear main wheels 21 and 22 are respectively placed on the effective contact range MR of the inner link 10, so that the influence of the step D is affected. Absent.

  The auxiliary wheel 23 is preferably disposed near the laser distance meter 24. In the state where the auxiliary wheel 23 is floating as described above, since the front and rear main wheels 21 and 22 are on the effective contact range MR of the inner link 10, the postures of the frame 20 and the laser rangefinder 24 are stable. ing. On the other hand, when traveling in the non-measurement position, the auxiliary wheel 23 is placed on the inner link 10, but it is also assumed that at least one of the front and rear main wheels 21, 22 is floating, By satisfying the formulas (1) and (2), since the auxiliary wheel 23 is in the vicinity of the laser distance meter 24, the laser distance meter 24 is hard to be vibrated and stabilized. As the laser distance meter 24 enters the measurement in such a stable state, it is possible to avoid unnecessary vibrations being input to the laser distance meter 24.

  As described above, according to the present embodiment, when the equipment is stopped, it is possible to stably move on the link chain 1 where the level difference D is generated and to perform measurement with high accuracy. Since it is not necessary to install a measuring device or install a measuring device for each facility, the measuring time can be shortened, the efficiency can be improved, and the chain elongation determination can be made correctly.

Next, examples according to the present invention will be described.
In this embodiment, the distance L3 between the rear main wheel 22 and the auxiliary wheel 23 is set to the chain pitch CP (the distance between the connecting pins 12 of the chain), and the output portion 24a and the auxiliary wheel 23 of the laser distance meter 24 are connected to the front wheel 23. The case where the distances L1 and L2 from the partial main wheel 21 are set to a length longer than the chain pitch CP by the distance x ′ will be described. The encoder 25 is set to detect the rotation angle of the front main wheel 21.

At this time, since the link chain 1 with a chain pitch CP (distance between the connecting pins 12 of the chain) of 250 mm was targeted, the axle distance of the pair of main wheels 21 and 22 was set to 505 mm. The measurement reference distance (chain pitch CP reference length) was 193 mm.
Then, by manually rolling (moving) the elongation measuring device SW, the elongation of the link chain 1 was measured by running the elongation measuring device SW on the ascending link chain 1A.

Here, because the specification of the encoder 25 in this embodiment is 2000 pulses / rotation, the measurement resolution is 0.25 mm in consideration of the outer diameter of the main wheels 21 and 22. In order to further increase the resolution, it is preferable to change the specification of the encoder 25 and select one having a large number of pulses per rotation.
Table 1 shows the measurement results and the actual measurement results using a steel scale.

As can be seen from Table 1, the actual measurement result and the actual measurement result by the measuring device coincided with each other with high accuracy. That is, since the deviation is smaller than 0.25 mm, it is less than the apparatus resolution and good accuracy is ensured.
Then, since the actual measurement result and the actual measurement result by the measuring apparatus of the present invention can coincide with each other with high accuracy, it can be understood that an appropriate chain replacement determination can be made.

DESCRIPTION OF SYMBOLS 1 Link chain 1A Ascending side link chain 3 Sprocket 3a Tooth 10 Inner link 11 Outer link 12 Connecting pin 13 Connecting pin mounting hole 20 Frame 21, 22 A pair of main wheels 23 Auxiliary wheel 24 Laser distance meter 24a Output part 24b Laser optical axis 25 Encoder 26 Calculation unit 26A Interval calculation unit 26B Elongation amount calculation unit D Step L1 Distance between axes L2 between front main wheel 21 and auxiliary wheel 23 Distance L3 between front main wheel 21 and output part of laser optical axis Rear main Inter-axis distance SR between wheel 22 and auxiliary wheel 23 Measurement range SW Elongation measuring device MR Effective contact range x Limit amount of chain elongation allowed between links x 'From the center of the chain pin to the end in the longitudinal direction of the link distance

Claims (5)

An elongation measuring device for detecting the elongation of a link chain formed by alternately connecting outer links and inner links,
A frame arranged along the chain extending direction;
A pair of main wheels attached to the frame apart from each other;
An auxiliary wheel attached to the frame between the pair of main wheels;
A laser rangefinder attached to the frame between the pair of main wheels and directed downward in the detection direction;
An encoder that is supported by the frame and detects rotation of one of the pair of main wheels;
Based on the detection value of the laser distance meter and the detection value of the encoder, an interval calculation unit that calculates the distance between adjacent inner links,
With
In top view, the position between the pair of chain pin centers in each inner link is defined as the effective contact range,
The distance between the axis of the one main shaft and the auxiliary wheel is L1, the distance between the laser beam output portion of the laser rangefinder and the axle of the one main wheel in a top view is L2, and the pair of main wheels When the inter-axis distance between the other main wheel and the auxiliary wheel is L3,
In the state where the distance between the adjacent inner links is being measured, the distances L1, L2, and L3 are set so that a pair of main wheels are located in the effective contact range of the different inner links. Elongation measuring device characterized. In a state in which the distance between the adjacent inner links is measured, each of the pair of main wheels is located in the contact effective range of any of the adjacent inner links,
In the top view, when the limit amount of chain elongation allowed between the links is defined as x and the distance from the chain pin center to the link longitudinal end on the near side is defined as x ′,
The inter-axis distance L1 is set based on the chain pitch, x and x ′, the distance L2 is set based on the chain pitch and x ′, and the inter-axis distance L3 is set equal to the chain pitch. The elongation measuring device according to claim 1.   The elongation measuring device according to claim 1 or 2, wherein the auxiliary wheel is disposed at a position closer to a laser beam output portion of the laser distance meter than the pair of main wheels.   4. The apparatus according to claim 1, further comprising: an elongation amount calculation unit that calculates an extension amount of the link chain from the distance between the inner links calculated by the interval calculation unit and a preset chain pitch reference length. The elongation measuring apparatus described in item 1. An elongation measuring method using the elongation measuring device according to any one of claims 1 to 4,
An elongation measuring method comprising: measuring the elongation by placing the elongation measuring device on an ascending side link chain in a chain conveyor having the link chain and moving the elongation measuring device in a chain extending direction.

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