JP5305963B2 - Method and apparatus for measuring link chain elongation - Google Patents

Description

  The present invention relates to a method and an apparatus for measuring the elongation of a link chain, and more particularly to a method and an apparatus for measuring the elongation of a link chain constituting an endless link device for stretching a sheet-like material such as a thermoplastic flat film.

  The stretching device for a thermoplastic flat film is obtained by pulling the film in the width direction or the length direction by a pair of endless link devices each having a plurality of clips each holding one end and multiple ends in the width direction of the film. It is configured to perform stretching. The endless link device constitutes a link chain by a number of links provided with clips, and adjacent links are connected to each other by a chain link and a link pin.

  In the stretching device having such a configuration, the link chain is extended due to wear of the link or the chain link provided with the clip and the link pin due to the addition of running resistance while being operated for a long time. And if the amount of elongation differs between a pair of endless link devices, or varies from part to part in one endless link device, the film will sag or pull and the quality of the product film Decreases. Moreover, in that case, productivity deteriorates due to a failure in gripping the film by the clip.

In order to solve such a problem, the link chain of each endless link device is driven by a separate motor, and one or more specific chain links in each endless link device are detected by a sensor. It is proposed that the speed of a pair of endless links be tuned by detecting the timing at which that particular chain link passes the sensor position and increasing or decreasing the number of rotations of each motor based on the timing deviation. (Patent Document 1).
Further, Patent Document 2 calculates the amount of extension of the link chain of the endless link device, and adjusts the travel speed of the endless link device based on the calculation result, thereby converting the travel speed to the line speed of the film production line. It is described to match. By doing in this way, it is possible to eliminate the film pulling and slacking between the front and back processes.

  In Patent Document 3, one endless link device is divided into a plurality of groups, and the detected bodies attached to the chain links of each group are installed at a distance in the length direction of the endless link device. A method is described in which the elongation of the link chain between the sensors is evaluated by the detection of the sensors, and the traveling speed of the endless link device is controlled accordingly.

JP 2004-155138 A Japanese Patent No. 3540909 JP 2006-224464 A

  However, in the techniques described in Patent Document 1 and Patent Document 2, the change in the length of a part of the link chain of one endless link device or the change in the difference in length between the link chains of a pair of endless link devices. I can't respond. Moreover, in the technique described in Patent Document 3, the evaluation of elongation is performed collectively for a plurality of link chains that constitute each group, but only the traveling speed is controlled according to the elongation as described above. The elongation itself is not measured.

  That is, in the techniques described in these patent documents, it is not possible to evaluate the elongation of the link, and it is possible to eliminate the deterioration of the quality of the product film caused by the elongation of the link or the film caused by the clip caused by the elongation. It is difficult to eliminate the occurrence of gripping defects.

  Therefore, the present invention measures the elongation of the link in the link chain with high accuracy, makes it possible to perform appropriate maintenance for each link, and when the link chain is used in a film stretching apparatus, the film has excellent quality. The purpose is to enable stable production.

In order to achieve this object, the link chain elongation measuring method of the present invention is:
Let n and m be integers,
In a link chain in which a plurality of links are connected to each other, a reference length link portion in which m links are connected to each other is prepared so that the start and end portions can be detected at the same timing by a pair of sensors,
Among the other m links to be measured, the n-th link at the start end and the n + m-1 link at the end are detected by the pair of sensors, and at the time of the detection, Find the time difference between the detection timing of the nth link and the detection timing of the (n + m-1) th link,
Using the time difference and the moving speed of the link chain, obtain the amount of change from the reference length for the m other links ,
A pair of sensors are stationary with respect to the traveling link chain,
A first change amount from a reference length for the n-th to m-th links when a specific link in the link chain becomes the n + m-th link by traveling of the link chain, and the specific link is the link The first difference value is obtained from the second change amount from the reference length for the n-th to m-th links when the chain becomes the (n + m-1) -th link by running the chain,
A third variation from a reference length for the n-th to m-th links when the specific link in the link chain becomes the n-th link by running of the link chain, and the specific link is the link The second difference value is obtained by the fourth change amount from the reference length for the n-th to m-th links when the chain becomes the (n-1) -th link by running the chain,
The extension amount of the specific link is estimated from the first difference value and the second difference value .

The link chain elongation measuring device of the present invention is
Let n and m be integers,
First and second sensors capable of detecting at the same timing the start end and the end of a link portion of a reference length in which m links are connected to each other in a link chain in which a plurality of links are connected to each other;
When the first and second sensors detect the nth link at the start end and the n + m−1 link at the end of the other m links to be measured, the nth link The time difference between the detection timing of the No. link and the detection timing of the (n + m-1) th link is obtained, and the reference length for the m other links is calculated using the time difference and the moving speed of the link chain. An arithmetic processing unit capable of obtaining a change amount of
I have a,
The first and second sensors are stationary with respect to the traveling link chain,
The arithmetic processing unit
A first change amount from a reference length for the n-th to m-th links when a specific link in the link chain becomes the n + m-th link by traveling of the link chain, and the specific link is the link The first difference value can be obtained from the second change amount from the reference length for the n-th to m-th links when the chain becomes the (n + m-1) -th link by running the chain,
A third variation from a reference length for the n-th to m-th links when the specific link in the link chain becomes the n-th link by running of the link chain, and the specific link is the link The second difference value can be obtained from the fourth change amount from the reference length for the n-th to m-th links when the chain becomes the (n-1) -th link by running the chain,
In addition, it is possible to estimate an extension amount of the specific link from the first difference value and the second difference value .

  According to the present invention, by using the time difference between the detection timings of the pair of sensors, the amount of change from the reference length for m links can be obtained with high accuracy.

  Further, according to the present invention, the first difference value when a specific link enters the m link strings and the second difference value when the specific link goes out of the m link strings are obtained. It is possible to estimate the extension amount of the specific link by using the first difference value and the second difference value.

It is a figure which shows an example of the measurement data by the measuring method of the elongation of the link chain of embodiment of this invention. It is a figure which shows the other example of the measurement data by the same measuring method. It is a figure which shows the measurement data before and after the maintenance of a link chain, respectively. It is a figure which shows the example of the specific numerical value of measurement data. It is a figure which shows the condition at the time of the measurement by the measuring device of the link chain elongation of embodiment of this invention. It is a whole top view of the measuring device. It is an enlarged view of the principal part in FIG.

  FIG. 6 shows a schematic configuration of a stretching apparatus for a thermoplastic flat film. Here, 1 is a thermoplastic flat film to be stretched, 2 is its length direction, and 3 is its width direction. The film 1 is manufactured in an unstretched state in a continuous form in the length direction by a manufacturing apparatus. The illustrated stretching apparatus 10 stretches the film 1 in the width direction. In the film 1, 4 is an unstretched portion, 5 is a stretched portion, and 6 is a stretched portion. That is, the film 1 is stretched in the width direction by the stretching device 10 while traveling in the direction of the arrow 7 in the drawing in the manufacturing process.

  The stretching device 10 includes a pair of endless link devices 11 and 11 on both sides of the film 1 along the width direction of the film 1. As shown in FIGS. 6 and 7, the endless link device 11 is configured as an endless link chain by connecting a large number of links 12, 12,... With a chain link 13 and a connecting pin 14. Has been. And the endless link apparatus 11 is arrange | positioned along the driving | running route which the edge part of the width direction should take when extending | stretching the film 1, as shown in FIG. Specifically, the endless link devices 11 and 11 are wound around a sprocket (not shown) and guided by a guide rail 19 shown in FIG. 7, thereby synchronizing the traveling speed of the film 1 along a predetermined route. And can be moved.

  Each link 12 has a clamper 15 that can clamp the end of the film 1 along the width direction of the film 1. For this reason, in the unstretched part 4 of the film 1, both ends in the width direction of the film 1 are clamped by the clampers 15 and 15 provided on the links 12 and 12 of the pair of endless link devices 11 and 11, respectively. By moving the link devices 11 and 11 in synchronism with the film 1, the endless link devices 11 and 11 pull the film 1 so as to spread in the width direction, whereby the film 1 is stretched. The stretched portion 5 is stretched in the width direction. In the portion 6 where the stretching has been completed, the film 1 is subjected to relaxation heat treatment by a heat treatment apparatus (not shown). The heat-treated film 1 is released from the endless link devices 11 and 11 at the end of the stretched portion 6 and sent to the next step.

  The endless link device 11 constituting the link chain is worn between the link 12 and the connecting pin 14 and between the chain link 13 and the connecting pin 14 as the operation time elapses. The resulting wear increases the length of the link chain over time.

  As shown in FIG. 6, the endless link device 11 is provided with a stationary first sensor 16 that can detect a specific part of an arbitrary link 12 that is moving. Further, the endless link device 11 includes a stationary type that can detect the same specific portion in another link 12 that is spaced from the link 12 along the length of the link chain by n pitches of the link 12. Two sensors 17 are provided. Detection signals from the first and second sensors 16 and 17 are configured to be sent to the arithmetic processing unit 18.

  Since the link 12 is generally formed of a magnetic material such as a steel material, a magnetic proximity sensor can be suitably used as the sensors 16 and 17. Although it is possible to use a laser displacement meter or the like, the magnetic proximity sensor has the advantage that it is less susceptible to the detection atmosphere.

  In such a configuration, the arithmetic processing unit 18 is configured so that the time when the first sensor 16 detects the specific part of the arbitrary link 12 and another link having a distance of n pitches from the arbitrary link 12. It is possible to take a time difference from the time when the second sensor 17 detects the same specific part in FIG.

  An arbitrary link 12 and another link 12 having a distance corresponding to the pitch of n from this link do not need to be two consecutive (that is, n = 1), but three or more consecutive It may be configured to detect the head link 12 and the tail link 12 in the link. When detecting three or more links, the detection is performed in units of the length of a series of links. In this case, it is impossible to directly and accurately determine the elongation of each link, but the absolute value of the lengths of a plurality of links to be measured is increased, so that detection data with higher accuracy can be obtained. The value of n, that is, the number of links can be appropriately selected according to the detection purpose, the accuracy of the sensors 16 and 17 to be used, the detection speed, the information processing speed of the arithmetic processing unit 18, and the like.

For example, when the pitch between the adjacent links 12 and 12 is 100 mm, the first and second sensors 16 and 17 are located at a position where n = 10, that is, 1 m which is a distance corresponding to a pitch of 10 pieces. Is detected and the difference in elongation of 1 mm (0.001 m) corresponding to 0.1% of the total length is evaluated. At this time, if the endless link device 11 is moved at a speed of 10 m / min,
0.01 ÷ (10 ÷ 60) = 0.006sec
Therefore, measurement in units of at least 0.001 sec is required. Therefore, it is necessary to use a sensor capable of measuring at about 1000 Hz, but a general magnetic proximity sensor can sufficiently satisfy this performance.

  As shown in FIG. 5, each link 12 is assigned an individual number 1, 2,. In this case, the second sensor 17 can detect the sixth link that is 5 distances away from the first link that can be detected by the first sensor 16. At this time, the distance from the first link to the sixth link varies according to the degree of elongation based on the wear of the link chain at that time. Therefore, for example, the distance from the first link to the sixth link in an arbitrary wear stage is set as the reference length, and the distance from the first sensor 16 to the second sensor 17 is adjusted to this reference length. Set. Then, as shown in FIG. 5A, when the first sensor 16 detects the first link, the second sensor 17 simultaneously detects the sixth link. Similarly, if the first sensor 16 and the second sensor 17 simultaneously detect the link 12 when measured for any set of five links, the elongation of the set of five links is the reference It can be determined that the extension of the set of five links from No. 1 to No. 6 including No. 1 is the same.

Next, it is assumed that the elongation between the sixth link and the seventh link is large with respect to the reference, that is, the wear amount is large with respect to the reference. Then, as shown in FIG. 5B, when the first sensor 16 detects the second link, the second sensor 17 has not yet detected the seventh link. That is, the detection timing of the seventh link is delayed with respect to the detection timing of the second link. Then, the set of five links from No. 2 to No. 7 including No. 2 is compared with the above-mentioned reference length,
(Delayed time) x (Link chain moving speed)
It will only be long and its value can be measured.

  Under these conditions, when the two sensors 16 and 17 detect the third link and the eighth link as shown in FIG. 5C, the set of these links is described above. Similarly, since there is a portion between the 6th link and the 7th link that is greatly expanded with respect to the reference, the detection timing of the 8th link is similarly detected with respect to the detection timing of the 3rd link. Is delayed.

On the other hand, when a portion including a portion having a small elongation with respect to the reference is detected, the following occurs. That is, as shown in FIG. 5D, it is assumed that the elongation between the 16th link and the 17th link is small with respect to the reference, that is, the wear amount is small with respect to the reference. Then, as shown in the drawing, before the first sensor 16 detects the 12th link, the second sensor 17 detects the 17th link early. Then, this set of links from No. 12 to No. 17 including No. 12 is compared with the above-mentioned reference length,
(Early time) x (moving speed of link chain)
Will be only short and its value can be measured.

  According to the present invention, by examining the detection timing of the second sensor 17 with respect to the detection timing of the first sensor 16 as described above, the elongation due to wear of the plurality of link sets at that time is the reference. You can know how it is.

  FIG. 4 shows an example of detection results for the 250th link to the 300th link. The first column of the illustrated data indicates the link number, and the second column indicates the amount of expansion for the set of 10 links up to the link having the number described in the first column. The third column shows the amount of extension for the set of 10 links up to the numbered link listed in the first column and the amount of extension for the set of 10 links up to the previous numbered link. Indicates the difference. Here, this difference is referred to as a front-back difference.

  Now, pay attention to the 274th link. Here, the elongation amount of the nth link is represented by δn. Further, the measured value of the elongation for the set of 10 links up to the nth link is Σn.

Then, from the illustrated data, Σ273, which is the sum of the elongation amounts δ264 to δ273, is 1.103 mm. Further, Σ274 which is the sum of δ265 to δ274 is 3.059 mm. Therefore, if the amount of change in elongation between Σ273 and Σ274 is Δ274,
Δ274 = Σ274−Σ273 = 1.956 mm = −δ273 + δ274
It becomes.

Similarly, from the illustrated data, Σ283, which is the sum of the elongation amounts δ274 to δ283, is 2.369 mm. Further, Σ284, which is the sum of δ275 to δ284, is 0.440 mm. Therefore, if the amount of change in elongation between Σ283 and Σ284 is Δ284,
Δ284 = Σ284−Σ283 = −1.929 mm = −δ274 + δ284
It becomes.

  Based on the absolute values of Δ274 and Δ284 described above and their positive and negative values, it can be estimated that the elongation amount δ274 of the 274th link is a large value. This can also be determined from the fact that when the elongation amount δ264 of the 264th link and the elongation amount δ284 of the 284th link are evaluated, they are not large values.

  FIG. 1 is a graph in which the horizontal axis represents the link number n, and the vertical axis represents the total sum Σ of the elongation amounts δ for 10 links up to the link of that number. In FIG. 2, the horizontal axis indicates the link number n, and the vertical axis indicates the amount of change Δn in the extension of the link of the number n, and the amount of change Δn (n + 10) in the extension of the n + 1th link after the tenth. It was taken. For example, δ274 and δ284 are shown for the 274th link. The administrator creates such a graph, sets the management value reference value appropriately (for example, set to 1.00), and determines whether both data of δ274 and δ284 exceed this management reference value By doing so, the abnormality can be determined at a glance. Such determination of abnormality can be performed by arithmetic processing without manually creating a graph inside the arithmetic processing unit 18 shown in FIG.

  In this way, a set of a plurality of links in which an abnormality is detected can be subjected to maintenance such as replacement with a new one. 3 is the same as that shown in FIG. 1 for the endless link device having the links from No. 1 to No. 401, including No. 250 to No. 300 shown in FIG. 4 and FIG. It is the graph which took and expressed the sum total (SIGMA) of elongation (delta) about ten links. FIG. 9A shows the situation before maintenance, and the sum Σ of the elongation δ is a large value for the 202nd to 302nd links. On the other hand, FIG. 5B shows the total sum Σ of the elongation δ after these links No. 202 to No. 302 are replaced with new ones by maintenance. As shown in the figure, it can be seen that after maintenance, the sum Σ of the elongation δ is small for the 202nd to 302th links where the sum Σ of the elongation δ was large before the maintenance.

  As described above, according to the present invention, it is possible to measure the elongation of each link in the link chain with high accuracy and perform appropriate maintenance for each link. For this reason, when the link chain is used for a film stretching apparatus, a film excellent in quality can be produced stably.

  In the above description, the stretching apparatus that stretches the film only in the width direction has been described. However, the present invention similarly applies to a so-called biaxial stretching apparatus that stretches the film in the length direction as well. Can be applied.

  Further, the present invention can be used not only for the link chain in the above-described film stretching apparatus but also for the link chain in other apparatuses.

11 Endless Link Device 12 Link 16 First Sensor 17 Second Sensor 18 Arithmetic Processing Device

Claims (2)

Let n and m be integers,
In a link chain in which a plurality of links are connected to each other, a reference length link portion in which m links are connected to each other is prepared so that the start and end portions can be detected at the same timing by a pair of sensors,
Among the other m links to be measured, the n-th link at the start end and the n + m-1 link at the end are detected by the pair of sensors, and at the time of the detection, Find the time difference between the detection timing of the nth link and the detection timing of the (n + m-1) th link,
Using the time difference and the moving speed of the link chain, obtain the amount of change from the reference length for the m other links ,
A pair of sensors are stationary with respect to the traveling link chain,
A first change amount from a reference length for the n-th to m-th links when a specific link in the link chain becomes the n + m-th link by traveling of the link chain, and the specific link is the link The first difference value is obtained from the second change amount from the reference length for the n-th to m-th links when the chain becomes the (n + m-1) -th link by running the chain,
A third variation from a reference length for the n-th to m-th links when the specific link in the link chain becomes the n-th link by running of the link chain, and the specific link is the link The second difference value is obtained by the fourth change amount from the reference length for the n-th to m-th links when the chain becomes the (n-1) -th link by running the chain,
A method for measuring the elongation of a link chain, wherein the amount of elongation of the specific link is estimated from the first difference value and the second difference value . Let n and m be integers,
First and second sensors capable of detecting at the same timing the start end and the end of a link portion of a reference length in which m links are connected to each other in a link chain in which a plurality of links are connected to each other;
When the first and second sensors detect the nth link at the start end and the n + m−1 link at the end of the other m links to be measured, the nth link The time difference between the detection timing of the No. link and the detection timing of the (n + m-1) th link is obtained, and the reference length for the m other links is calculated using the time difference and the moving speed of the link chain. An arithmetic processing unit capable of obtaining a change amount of
I have a,
The first and second sensors are stationary with respect to the traveling link chain,
The arithmetic processing unit
A first change amount from a reference length for the n-th to m-th links when a specific link in the link chain becomes the n + m-th link by traveling of the link chain, and the specific link is the link The first difference value can be obtained from the second change amount from the reference length for the n-th to m-th links when the chain becomes the (n + m-1) -th link by running the chain,
A third variation from a reference length for the n-th to m-th links when the specific link in the link chain becomes the n-th link by running of the link chain, and the specific link is the link The second difference value can be obtained from the fourth change amount from the reference length for the n-th to m-th links when the chain becomes the (n-1) -th link by running the chain,
An apparatus for measuring the elongation of a link chain, wherein the amount of elongation of the specific link can be estimated from the first difference value and the second difference value .

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