JP2822888B2 - Web production method and production apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to manufacture a plastic film or cloth web while controlling the gripping position of a tenter clip in a cloth tentering machine, a plastic film stretching machine, a film tentering machine, a biaxial stretching machine or the like. And a manufacturing apparatus.

[0002]

2. Description of the Related Art For example, in a stretching process in the production of a stretched film, a resin is stretched at an appropriate temperature below the melting point to give orientation to molecules and crystals, thereby improving mechanical strength, optical properties and gas permeability. And other properties that cannot be obtained when unstretched. Stretching methods are classified into several types according to a method of stretching a film and a film form. For example, a flat film stretching method in which a film is extruded by a T-die and then continuously stretched by a simultaneous biaxial stretching device or a sequential stretching device. is there. The sequential stretching device solidifies the film extruded from the die with a cooling roll into a stretching raw fabric, heats the stretched raw fabric to a stretching temperature, stretches the roll in the longitudinal direction by a roll, cools, and then cools the corresponding longitudinal stretch. After gripping both ends of the film with a tenter clip, the film is introduced into a horizontal stretching device, stretched in the horizontal direction under heating, and then heated at an appropriate temperature while being tensioned to fix the orientation. It is removed and wound up on a winder.

[0003] As an apparatus for manufacturing a film while gripping the edge of the film with a tenter clip,
A configuration as shown in FIGS. 5 and 6 is known. In FIG. 5, a pair of left and right tenter clips 1 are mounted on a pair of clip tables 3 slidably disposed on rails 2 respectively.
Moves at a predetermined speed from the tenter inlet portion 8a (FIG. 6) toward the tenter outlet portion 8b, and is reversed by 180 ° by the wear ring 10 at the tenter outlet portion 8b.
And is reversed again by another wear ring 9. In such a manufacturing apparatus, the tenter clip 1 as described above is used, for example, in a number of 50 per tenter.
Stretching (transverse stretching) in the web width direction is performed while gripping the edge of the film by using about 0 to 2500 pieces. The clip body 4 is placed and fixed on the clip base 3 and has an upright portion that stands up from the clip base 30 in an arch shape.
A clip lever 6 is attached to the upper end of the upright portion by a support shaft 5.
Is rotatably supported at a substantially central portion thereof.

[0004] The clip lever 6 is a spring 1 stretched between the clip lever upper part 31 and the clip body 4.
The film 11 is pivoted to the position shown by the solid line by the spring force of the film 2 and between the clip lever edge 33 of the clip lever lower part 32 and the liner 7 disposed on the clip base 30.
At both ends (hereinafter, referred to as “edges”). Further, clip openers 34 and 36 and clip closers 35 and 37 are provided at the tenter outlet 8b and the tenter inlet 8a.

The left and right edges of the film 11 are gripped between the clip lever edge 33 and the liner 7, move together with the clip table 3 sliding on the rail 2, and move laterally (left and right) while passing through the tenter 8. At a predetermined magnification. When the upper portion 31 of each clip lever comes into contact with the clip opener 34 and the wear ring 10 of the tenter outlet portion 8b, the left and right clip levers 6 rotate as shown by a two-dot chain line in FIG. The grip of both edges of the film 11 is released, and the film 11 is sent to the next process.

Next, when the right and left tenter clips 1 are turned by 180 °, respectively, and the upper portion 31 of the clip lever comes into contact with the wear ring 10 and the clip closer 35, these clip levers 6 are actuated by the spring force of the spring 12, and the solid line in FIG. To return to the position. On the other hand, in the tenter inlet portion 8a, the clip lever 6 has a clip lever upper portion 31 and a clip opener 36 and a wear ring 9.
Is rotated to the position indicated by the two-dot chain line in FIG.
When the upper portion 31 of the clip lever comes into contact with the clip closer 37, it returns to the position shown by the solid line again and grips both edges of the film 11.

When the film 11 meanders or changes its width in the longitudinal direction while being conveyed to the tenter 8, if the interval between the tenter clips on the left and right of the tenter entrance 8a is constant, the edge of the film 11 is correctly determined. Cannot be grasped, and as a result, the film 11 is torn, and in some cases, the film 11 is caught in the apparatus, which causes a failure.

Therefore, the tenter entrance 8a, that is, the left and right wear rings 9, the clip opener 36, the clip closer 37, and the rail 2 at the entrance are respectively connected to the rotating shaft 1
The tenter clip is installed on a cell page guider 15 rotatable around the center 6 so that the interval between the right and left tenter clips of the tenter entrance 8a can be adjusted. Further, an edge relative position sensor 17 is disposed at a position immediately before the film 11 is gripped between the clip lever 6 and the liner 7 of the tenter clip 1 in an open state on each cell page guider 15 so that the edge of the film 11 and the cell page guide 15 are always in contact. When the width of the film 11 becomes narrower, the left and right self-page guiders 15 are turned inward, and when the width of the film 11 is wide, the cell-page guiders 15 are turned outward, Tenter clip 1
Controls so as to always hold the left and right edges of the film 11 correctly (such a control method is called “relative position control”). In addition, as the edge relative position sensor,
An air-type sensor that blows air downward from above and determines the presence or absence of a film edge based on received air pressure;
Or, similarly, an ultrasonic sensor using ultrasonic waves is employed. In addition, laser scan method and CCD camera
Mela method is also used.

In this conventional web manufacturing apparatus, since the edge relative position sensor 17 itself moves together with the self-page guide 15, the width of the film 11 and the absolute position of the edge are not measured, but the edge sensor 17 is always self-tuned. There is an advantage that the film edge can be controlled to be located at the center.

However, the present inventors have found that such a conventional web manufacturing apparatus or manufacturing method has the following control instability. That is, since the cell page guider 15 rotates the tenter entrance side around the rotation shaft 16, the cell page guider 15 is rotated to accurately grip the film edge, and the center of the edge relative position sensor 17 matches the film edge position. Then, among the tenter clips already gripping and running on the film edge, those at the intermediate portion between the edge relative position sensor 17 and the rotation axis (hereinafter abbreviated as “rotation axis upstream portion”) are also included. Moving. Therefore, when the tenter clip moves inward to grip the film edge by the control, the edge of the rotating shaft upstream part escapes further inward, and conversely, when the clip moves outward, the edge of the rotating shaft upstream part moves. Escapes further outwards, which is an undesirable positive feedback. In such a case, when the tenter clip first moves inward, the edge of the rotation shaft upstream part escapes inward, and then the tenter clip moves further inward, and after repeating the operation of moving inward to some extent, This time, the tenter clip moves outward, the edge of the upstream portion of the rotary shaft escapes outward, and the tenter clip moves in a vibrating manner.
The frequency of such vibration is determined by the edge relative position sensor 17.
And the natural frequency of the system from the drive to the drive unit of the cell page guider 15 coincides with the natural frequency.

In a control system having such positive feedback, when the gain is increased, there is a danger that the system oscillates at a frequency that matches the natural frequency of the system and hunting occurs. For this reason, for example, a dead zone in which the sensitivity of the edge relative position sensor is extremely reduced has to be provided, and the gain of the entire control system has to be reduced. As a result, the response of the control system becomes slow and it is not possible to follow the change in the film width, which has caused defects such as breakage of the film. In particular, when it is not desired to make the gain of the entire control system extremely low, a dead zone is provided in the edge relative position sensor before and after the control is locked.
Because of the value control, smooth control could not be performed.

The film 1 conveyed in the tenter 8
In Example 1, the holding amount of the tenter clip is 18 mm, for example.
It was fixed to the extent. However, since the conditions such as the stretching ratio vary depending on the type of film, the optimum gripping amount also varies. If the gripping amount is not the optimum value, for example, if the gripping amount is too small, it may cause clip detachment in the tenter, and if the gripping amount is too large, the film may be broken due to excessive stretching in the width direction of the film. Was. Even if the film does not break, the portion discarded as waste increases when the film gripping amount is larger than necessary. Also, once the film breaks, all the products wound up to that point will be defective,
In addition, the time required for the production to be restored and the waste of the raw material during that time are generated, causing a significant decrease in productivity.

[0013] Therefore, particularly when manufacturing a film while frequently changing the product type, it is inevitable that a trouble due to a defective gripping amount of the film edge of the tenter clip occurs.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-described problems. And a web manufacturing apparatus.

[0015]

The gist of the present invention to achieve the above object is as follows.

According to the method of manufacturing a web of the present invention, an absolute position in the web width direction of the tenter clip at a gripping point of the edge of the running web at the tenter clip is detected, and an edge of the web edge upstream of the gripping point is detected. An absolute position in the web width direction is detected, and a web grip amount of the tenter clip at the grip point is obtained from the detected absolute position in the web width direction of the tenter clip and the absolute position of the edge of the web in the web width direction. The web is stretched in the web width direction by the tenter clip while controlling the position of the tenter clip so that the web grip is equal to a predetermined web grip.

Another aspect of the web manufacturing method of the present invention is to detect a relative position in the web width direction of the edge of the web with respect to the tenter clip near the grip point of the edge of the running web by the tenter clip. Calculating the web gripping amount of the tenter clip from the relative position, and controlling the position of the tenter clip so that the web gripping amount is equal to a predetermined web gripping amount, and webbing the web by the tenter clip. Stretching in the width direction, and then, in place of the detection of the relative position, the absolute position in the web width direction of the tenter clip at the grip point and the absolute position in the web width direction of the edge of the web upstream of the grip point. Is detected, and the absolute position of the detected tenter clip in the web width direction and disconnection of the edge of the web are detected. From the position, the web gripping amount of the tenter clip at the gripping point is determined, and while controlling the position of the tenter clip so that the web gripping amount is equal to the predetermined web gripping amount, the web width is adjusted by the tenter clip. It is characterized by stretching in the direction.

In a preferred aspect of the web manufacturing method of the present invention, an edge sensor movable in the web width direction and an edge sensor in the web width direction of the edge sensor are detected when detecting the absolute position of the edge of the web in the web width direction. The absolute position of the edge of the web in the web width direction is detected by the edge absolute position detecting means comprising an edge sensor position detecting means for detecting a position.

In a preferred aspect of the web manufacturing method according to the present invention, the means for detecting the absolute position of the edge further has a power for moving the edge sensor.

The web manufacturing apparatus according to the present invention further comprises: a tenter clip; means for detecting an absolute position of an edge of the running web at a gripping point of the tenter clip in a web width direction; Detecting means for detecting the absolute position of the edge of the web in the web width direction upstream of the detecting means, detecting the absolute position of the tenter clip in the web width direction, and detecting the absolute position of the edge of the web in the web width direction. A web gripping amount calculating means for calculating a web gripping amount of the tenter clip at the gripping point from the detected output, a web gripping amount setting means for setting the web gripping amount, and a web gripping calculated by the web gripping amount calculating means. Position of the tenter clip so that the amount is equal to the web grip amount set by the web grip amount setting means. It is characterized by comprising a control for tenter clip-position control means.

In another aspect of the web manufacturing apparatus of the present invention, a tenter clip and a relative position of the edge of the running web with respect to the tenter clip in the web width direction in the vicinity of a grip point of the tenter clip by the tenter clip. Detecting means, a first web gripping amount calculating means for calculating a web gripping amount of the tenter clip at the gripping point from a detection output of a detecting means of a relative position of the edge in a web width direction, Detecting means for detecting the absolute position of the tenter clip in the web width direction at the gripping point by the tenter clip; detecting means for detecting the absolute position of the edge of the web upstream of the gripping point in the web width direction; Detection output of the absolute position detecting means and detection of the absolute position of the edge of the web in the web width direction. A second web gripping amount calculating means for calculating a web gripping amount of the tenter clip at the gripping point from the force, and an output of the first web gripping amount calculating means and an output of the second web gripping amount detecting means. A web gripping amount transmitting means for selectively transmitting one of them, a web gripping amount setting means for setting a web gripping amount, and a web gripping amount transmitted by the web gripping amount transmitting means set by the web gripping amount setting means. Control means for controlling the position of the tenter clip so as to be equal to the set web grip amount.

In a preferred aspect of the web manufacturing apparatus according to the present invention, the means for detecting the absolute position of the edge of the web in the web width direction includes an edge sensor movable in the web width direction and a web width direction of the edge sensor. And an edge sensor position detecting means for detecting the position of the edge sensor.

In a preferred aspect of the web manufacturing apparatus according to the present invention, the means for detecting an absolute position of the edge of the web in the web width direction further has a power for moving the edge sensor. I have.

In a preferred aspect of the web manufacturing apparatus according to the present invention, the web manufacturing apparatus further comprises a web gripping amount correcting means based on a difference between the edge absolute position sensor and the gripping point in the web running direction. Features.

[0025]

According to the web manufacturing method of the present invention, the absolute position of the edge of the web is detected on the upstream side which is not affected by the rotation of the self-page guider, the absolute position of the tenter clip is detected, and based on these detection results. Therefore, since the gripping amount of the web by the tenter clip is controlled, undesired positive feedback does not occur in the control.

Further, according to the web manufacturing method of the present invention, the absolute position of the edge of the web and the absolute position of the tenter clip are detected to determine the grip amount by the tenter clip.
Alternatively, the relative position of the edge of the web to the tenter clip is detected to determine the amount of grip by the tenter clip, and the obtained grip amount is controlled to be equal to the preset grip amount. The grip amount can be determined.

According to a preferred embodiment of the web manufacturing method of the present invention, an edge sensor capable of moving the absolute position of the web edge in the web width direction and an edge sensor for detecting the position of the edge sensor in the web width direction are provided. Since the absolute position of the edge is detected by the position detecting means, the absolute position of the edge of the web can be measured at any position in the web width direction.

Hereinafter, an embodiment of the web of the present invention will be described in detail with reference to the drawings, taking as an example a step of manufacturing a web while laterally stretching a plastic film as the web.

First, the configuration of the web manufacturing apparatus used in this embodiment will be described.

In FIG. 1, the tenter inlet 8a, ie,
The left and right wear rings 9, the clip opener 36, the clip closer 37, and the rail (not shown) at the entrance are
Each of the cell page guiders 15 is installed on a cell page guider 15, and these cell page guides 15 are rotatable about a rotation shaft 16, respectively, so that the interval between the tenter inlet portions 8 a can be adjusted. At a position immediately before the film 11 of each cell guider 15 is gripped between the clip lever 6 and the liner 7 of the open tenter clip 1, an edge relative position sensor 17 for detecting a web edge relative position is provided. The edge relative position sensor 17 includes an air type and an ultrasonic type sensor as described above. Alternatively, a laser scan method, a CCD camera method, or the like can be used.

The edge absolute position sensor 18 changes the width of the film 11 on the upstream side of the left and right cell page guiders 15, that is, upstream of the point where the tenter clip grips the web edge, and by the rotation of these cell page guides 15. It is arranged at a position where the influence is equal to or smaller than a predetermined dimension (for example, 1 mm) (for example, about 1 to 5 m upstream from the gripping point). These edge absolute position sensors 18
Is an edge sensor carriage 14 movable in the web width direction.
It is placed on. The absolute position in the web width direction of the edge absolute position sensor 18 placed on the edge sensor moving base 14 is detected by the edge sensor position sensor 20. Therefore, the absolute position of the edge in the web width direction can be detected by a combination of the edge absolute position sensor 18 and the edge sensor position sensor 20. The use of the edge sensor movable base 14 in this manner is such that the edge absolute position detection sensor that requires high measurement accuracy has a narrow detectable range of about several tens of mm. This is because it is not possible to cope sufficiently. Such a configuration is preferable because it can flexibly cope with a change in web type and can maintain high measurement accuracy. Further, it is preferable that the edge sensor moving base 14 is provided with a power so that the edge absolute position sensor 18 can be moved to a position automatically set when the type is changed. In addition, it is preferable that the power followability is high because the edge position of the web can be detected accurately even when the fluctuation of the web width during the web manufacturing exceeds the detectable range of the edge absolute position sensor 18.

As the edge absolute position sensor 18, a non-contact type such as an ultrasonic type or an optical type is preferably used. Particularly, an optical sensor such as a laser scan system or a CCD camera system is preferable. Also, when measuring the edge of a transparent plastic film or the like, it is preferable to use a polarized light source as a light source by utilizing the polarization characteristics of the film, so that the detection can be performed more reliably. Further, as the edge sensor position sensor 20, the edge sensor moving base 1 is used.
4, which detects the position in the web width direction, regardless of the principle of contact type or non-contact type, it is possible to use a laser type displacement meter, an ultrasonic type displacement meter, a built-in potentiometer, etc. . A potentiometer is preferred for widening the detection range. In order to improve the followability, an optical type or the like is preferable.

A clip position sensor 19 is disposed on the base portion (vertical lower portion) of the left and right cell guiders 15. These clip position sensors 19 detect the position of the cell page guider 15, that is, the absolute position of the web gripping point of the tenter clip in the web width direction.
Similar to the edge sensor position sensor 20, the clip position sensor 19 may be of any type, regardless of contact or non-contact type, and may be a laser displacement meter, an ultrasonic displacement meter, a built-in potentiometer, or the like. It is possible. It is preferable that the clip position sensor 19 has the same followability and detection range characteristics as those of the edge sensor position sensor 20, and it is preferable to use the same type of sensor.

The setting of the grip amount is performed by a grip amount setting unit 21 for setting the grip amount of each side of the web installed on the operation unit (not shown). For example, a thumbwheel switch or a dip switch is preferably used as the grip amount setting unit 21. The setting may be made from a keyboard or the like using a screen of a computer or the like. The setting of the grip amount is preferably represented by, for example, a three-digit numerical value in units of 0.1 mm. This setting is transmitted to the control unit 23.

The output of the control unit 23 outputs one of a control signal for relative position control using the edge relative position sensor 17 or a control signal for absolute position control using the edge absolute position sensor 18. This switching is performed by operating the changeover switches 25 and 28 of the control unit 3 based on the output of the control changeover unit 22 provided in the operation unit. As the switching signal 22, for example, a contact signal is used. When the contact is closed, the absolute position control is selected, and when the contact is opened, the relative position control is selected. This switching may be manually performed by an operator depending on the state of the manufacturing process, or may be automatically performed.

The sign direction of each signal is, for example,
The output of the edge absolute position sensor 18 is positive in the direction from the outside of the web toward the center, the output of the clip position sensor 19 and the edge sensor position sensor 20 is the positive in the direction of the outside from the center of the web, and the output of the grip amount setting unit 21 is The edge relative position sensor 17 that defines the direction in which the gripping amount (always a positive value) increases as positive and detects the deviation between the edge position and the tenter clip position is used when the web edge is at the center of the sensor position detection range. With reference to the gripping amount, the direction in which the gripping amount increases is defined as positive, and the direction in which the gripping amount decreases is defined as negative. In this case, when a positive control signal is applied to the cell page guide driver, the cell page guide moves from the center of the web to the outside.

The signals from these sensors and the like are connected to the control unit 23 as shown in FIG. This control unit 23
For example, a PID control circuit (a proportional operation (P operation) for outputting a signal proportional to the deviation, an integration operation (I operation) for outputting a signal for removing the residual deviation, and a differential operation (D operation) for quick response). Control circuit).

As described above, the control method is switched between the absolute position control based on the edge absolute position and the relative position control based on the edge relative position. When performing control based on the edge absolute position, a difference signal between the sum of the signals of the edge absolute position sensor 18 and the edge sensor position sensor 20 and the output of the clip position sensor 19 (measured value of the gripping amount of the web edge by the tenter clip) To grip amount setting unit 2
A value obtained by subtracting the output of 1 is used as a control error signal. (Note that
In the calculation of the control error signal, when the types of the clip position sensor 19 and the edge sensor position sensor 20 are the same, these difference signals are calculated first as shown in FIG.
It is preferable that the difference between the difference signal and the signal of the edge absolute position sensor 18 is calculated and obtained. This is because the output level of the same type of sensor is uniform, so that the influence of noise of the circuit such as the difference calculator 24 can be reduced and fine control can be performed. On the other hand, when based on the edge relative position, the output signal of the edge relative position sensor 17 is used as the measured value of the grip amount, and the value obtained by subtracting the output of the grip amount setting unit 21 from this signal is used as the control error signal. . This switching of the control method is performed based on the signal of the control switching unit 22 as described above. This control error signal is given to the PID controller 26, and its output is sent to the cell page guide drive unit (not shown).
In addition to the above, the left and right cell page guiders 15 are driven. In the case of absolute position control, a signal of the PID controller 26 is given to the advance / delay compensation circuit once. This is for compensating for a change in the transfer function because the edge absolute position sensor 18 is on the upstream side of the clip position sensor 19.

The display of the gripping amount by the tenter clip when performing the absolute position control is performed by, for example, using a part of the control unit 23 as shown in FIG. It may be performed using a means. Clip position sensor 19, edge sensor position sensor 20
Are connected to the + input terminal and the-input terminal of the difference calculator 24a via the input terminals 23b and 23c, respectively, to perform the difference calculation. The edge absolute position sensor 18 has an input terminal 23a.
Is connected to the input terminal of the delay circuit 29, and the delay circuit 29 delays the input waveform by a predetermined delay time without substantially changing the input waveform. The output terminal of the delay circuit 29 is connected to the minus input terminal of the difference calculator 24d. ing. The delay time is
The time is determined by subtracting the time required for signal transmission between the edge absolute position sensor 18 and the input of the delay circuit 29 from the time determined by dividing the distance between the edge absolute position sensor 18 and the clip grip point by the film speed. . Difference calculator 24a
Is connected to the + input terminal of the difference calculator 24d, and the difference calculator 24d obtains a measured value of the actual grip amount at the clip grip point (referred to as "actual edge grip amount"). It is preferable to use this actual biting amount for displaying the gripping amount. Also, in the control of the cell page guider 15, when the position of the edge absolute position sensor 18 is far upstream (for example, 5 m or more) from the grip point, such an actual edge grip amount is used as a measured value of the grip amount. Is preferred.

Next, the operation of the above web manufacturing apparatus will be described with reference to FIGS.

The film 11 is transported as a wide and long object in the upstream process, and reaches the tenter entrance 8a. At the tenter entrance 8a, the left and right edges of the film 11 are gripped by the left and right tenter clips 1 (FIG. 6) that are driven to rotate, and various processes such as heat treatment and widening are performed in the tenter 8. Is done. At this time, the absolute positions of the film edges are detected by the left and right edge absolute position sensors 18 and the edge sensor position sensors 20 arranged and fixed on the transport (running) path of the film 11, and then the left and right edges arranged and fixed on the cell page guider 15. The edge relative position sensor 17 detects the relative position of the film edge with respect to the clip grip point. Further, the positions of the left and right cell page guiders 15, that is, the absolute positions of the left and right clip grip points are detected by the clip position sensor 19. The signals detected by these sensors are transmitted to the control unit 23.

The control unit 23 has a changeover switch 25 immediately after the start of film production or when the process conditions are unstable.
28 is switched to the contacts 25b and 28b. That is, immediately after the start of production, the width of the film 11 changes greatly until the speed reaches a predetermined line speed, and the film 11 meanders or changes greatly even when the process conditions are unstable. Or In such a case, the film 11 and the cell page guider 15 may not exist within the position detection ranges of the clip position sensor 19 and the edge absolute position sensor 18, and control may be lost. On the other hand, since the edge relative position sensor 17 detects the relative position, there is no such danger, and the edge relative position sensor 17 can grip the film edge.

The signal output from the edge relative position sensor 17 is sent from the input terminal 23e of the control unit 23 to the PID controller 26 via the changeover switch 25 as a deviation signal indicating the relative position between the edge gripping point of the tenter clip and the film edge. Is entered. The PID controller 26 calculates the input signal by using a predetermined control constant as a control signal, and outputs the control signal from the output terminal 23g via the changeover switch 28. This control signal is applied to a cell page guide drive unit (not shown), and when the output signal of the edge relative position sensor 17 is negative, that is, when the film edge tends to escape from the gripping point, the left and right cell page guides 15 are turned inward. When the signal is positive, that is, when there is a tendency to grip the film edge deeply, the self-page guider 15 is rotated outward to grip the film edge.

At this time, the cell page guider 15 rotates the tenter entrance side portion about the rotation axis based on the signal of the edge relative position sensor 17. If the self-page guider 15 is turned to move the center of the edge relative position sensor 17 to a position near the set film edge in order to accurately grasp the film edge, the rotation that has already been performed while grasping the film edge is performed. The clip on the upstream side of the moving shaft also moves at the same time. Therefore, when the clip moves inward to grip the film edge, the edge of the upstream portion of the rotating shaft escapes further inward, and when the clip moves outward, the edge of the upstream portion of the rotating shaft further outwards The width of the film 11 at the tenter entrance 8a is slightly changed by the edge fluctuation of the upstream portion of the rotation shaft. This is a disadvantage of the above-described relative value control. To avoid this, for example, a dead zone must be provided in the output of the edge relative position sensor 17 or the gain of the control system must be reduced to stabilize the control.

If the above countermeasures are taken, control will not be lost, but smooth control cannot be performed, which is not a preferable state. Therefore, after the production process has been accelerated, the predetermined line speed has been reached, and the process conditions have stabilized, the control switch 22 switches the switches 25, 28 of the control unit 23 to the contact points 25a, 28a, thereby controlling To the absolute position control. Before switching the changeover switches 25 and 28, the clip position sensor 19, the edge absolute position sensor 1
8. The measurement ranges of the edge sensor position sensor 20 and the grip amount setting unit 21 are matched. This transition of the control may be performed automatically based on the film width or the like, or may be performed manually.

When the changeover switches 25, 28 of the control unit 23 are switched to the contact points 25a, 28a, the signals from the clip position sensor 19, the edge absolute position sensor 18, the edge sensor position sensor 20, and the grip amount setting unit 21 are differentiated. Signals corresponding to the arithmetic operations are input to the arithmetic units 24 a to 24 c and input to the PID controller 26 via the changeover switch 25. The PID controller 26 calculates this input signal based on the predetermined control constant and outputs it as a control signal. This control signal is further supplied to the lead / lag compensation circuit 27.
After the advance / delay is compensated for a predetermined time, the control signal is output from the output terminal 23g via the changeover switch 28. In the case of absolute position control, the control constant may be set so as to increase the gain of the control system.

The control signal output from the control unit 23 is applied to the cell page guide drive unit, and the output of the difference calculator 24c is positive, that is, the edge absolute position sensor 1
8 and the measured grip amount obtained by subtracting the output signal level of the clip position detection sensor 19 from the signal level of the absolute position of the edge obtained from the edge sensor position sensor 20,
When the control signal obtained by subtracting the output of the grip setting unit 21 is positive, the left and right cell page guiders 15 are turned outward, and when the output of the difference calculator 24c is negative, the cell page guide 15 is turned inside. Then, always grip the film edge at the correct position.

At this time, the rotation of the cell page guider 15 causes the tenter clips already gripping the web edge to move together, and the width of the film 11 at the tenter entrance 8a is slightly changed. The influence of this change in width gradually decreases toward the upstream of the film. Since the edge absolute position sensor 18 is installed on the upstream side where there is almost no influence of the width change of the film 11,
Unwanted positive feedback as in the case of the relative position control described above is not applied to the control system. As a result, the gain of the control system can be sufficiently increased, and there is no need to provide a dead zone in the sensor, so that the clip gripping position can be controlled with high accuracy and high stability.

When the position detection range of the edge absolute position sensor 18 is sufficiently wide, it is preferable to use absolute position control from the beginning instead of switching between relative position control and absolute position control as described above.

The gripping amount of the web can be freely set by the gripping amount setting section 21, and it is possible to flexibly cope with a change in web type. Further, it is preferable to combine the edge absolute position sensor 18 and the edge sensor movable base 14 to extend the position detection range of the edge absolute position, because it is possible to cope with a wider variety of products.

In the present invention, the web refers to a sheet-like material such as a woven fabric or a plastic film. In particular, a plastic film is suitable as an application target of the present invention.

In the present invention, as a means for calculating the amount of web grip, a combination of an operational amplifier or the like using an analog or digital electronic circuit, or an analog or digital computer is preferably used.

In the present invention, the web gripping amount setting means may be a simple means such as a voltage or current output of an analog or digital electronic circuit, or a means for adjusting this output with switches such as a dip switch or a variable resistor. Anything that can set a set value is acceptable.
Further, the setting value may be dynamically changed while the web is running. Further, a device that automatically sets each product type using an output from a computer or the like is also preferably used.

Further, in the present invention, the tenter clip position control means includes a control signal processing section using an analog or digital electronic circuit, and a cell page guider driving section for driving the cell page guider based on the output of the control signal processing section. Is preferably used. As a control method, analog control such as PI control and PD control, and digital control other than the above-described PID control are preferably used. If the transfer function is simple, mechanical control may be used.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a web manufacturing method and a web manufacturing apparatus according to the present invention will be described below.

Using a web manufacturing apparatus having the structure shown in FIG. 1, a polyester film having a thickness of 13 μm and a width of 2 m was used as the film 11, conveyed at a film speed of 120 m / min, and an ultrasonic sensor was used as the edge relative position sensor 17. A laterally stretched film was manufactured using the laser scan type displacement measuring device as the edge absolute position sensor 18 and the potentiometer as the clip position sensor 19 and the edge sensor position sensor 20 while performing the above control. The setting of the grip amount was 14 mm.

As a result, the edge relative position sensor 18 is changed from the conventional relative position control using the edge relative position sensor 17.
FIG. 4 shows the signals of the edge absolute position sensor 18 and the clip position sensor 19 when the control is shifted to the absolute position control by switching to the above, and the web grip amount of the tenter clip 1 obtained from these signals.

In FIG. 4, (a) shows the absolute position of the edge of the film, (b) shows the displacement of the self-guide guide position, that is, the clip position, and (c) shows the time difference based on the difference between the positions of the two sensors in the web running direction. Represents the actual web gripping amount (actual edge gripping amount) which is a difference signal obtained by correcting. At the time indicated by the broken line in the center, the control method was switched from the control by the conventional control device (left) to the control by the control device of the present invention (right).

(A) is the film edge position, so that the change in the displacement does not show any characteristic change before and after the switching of the control method, whereas the displacement of the clip position shown in (b) is controlled. The conventional control method (relative position control) before switching can only roughly follow the movement of the position of the film edge, and the fine movement of (a) shows a monotonous displacement with a constant gradient. This is considered to be the effect of the dead zone of the edge relative position sensor set so that the control does not oscillate. Also, when the edge position shown in (a) greatly changes, the clip position in (b) is largely displaced in that direction, but hunting due to natural vibration occurs. In (c), the actual gripping amount fluctuates greatly from the set value due to poor followability of the clip position.

On the other hand, in the absolute position control after the control switching, the clip displacement in (b) almost exactly follows the change in the film edge in (a), and the vibration phenomenon due to hunting disappeared. Also, the actual grip amount in (c) has a small fluctuation range around the set value, and it is possible to control the clip grip position so as to have high accuracy, high response, high stability, and exactly match the set grip amount. It has become possible.

[0061]

As described above, according to the present invention, when controlling the position of the tenter clip, the web is manufactured while performing control based on the edge of the web and the absolute position of the tenter clip. Does not occur in the control, and smooth control with high accuracy and high followability can be realized. This greatly reduces web damage such as film breaks due to clip errors that were inevitable with conventional relative position control, greatly contributing to higher yields, and extending the mechanical life of the self-guided guider drive, There are excellent effects such as reduction in cost.

Further, since the web gripping amount by the tenter clip can be set, it is possible to flexibly cope with a change in web type. In addition, when detecting the absolute position of the edge, the range that can be handled is further expanded by combining the edge absolute position sensor and the edge sensor position sensor. As a result, the yield and productivity are improved without wasteful increase of the film debris at the edge portion, and because the stability of the stretching process is increased and tearing is reduced.

By moving the edge absolute position sensor using power, the web width can be changed more easily.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a web manufacturing apparatus according to the present invention.

FIG. 2 is a block diagram showing one embodiment of a control unit of the web manufacturing apparatus of the present invention.

FIG. 3 is a block diagram showing an embodiment relating to display output of a grip amount in a part of the control unit of FIG. 2;

FIG. 4 is a graph showing a result of fluctuation of each measured value in one embodiment of the present invention.

FIG. 5 is a part of a cross section of a conventional tenter.

FIG. 6 is a plan view of the tenter of FIG. 5;

[Description of Signs] 1: Tenter clip 2: Rail 3: Clip base 4: Clip body 5: Support shaft 6: Clip lever 7: Liner 8: Tenter 8a: Tenter inlet 8b: Tenter outlet 9: Wear ring 10: Wear ring 11: Film 12: Spring 14: Edge sensor movable base 15: Self-page guider 16: Rotating axis 17: Edge relative position sensor 18: Edge absolute position sensor 19: Clip position sensor 20: Edge sensor position sensor 21: Grip amount setting Unit 22: control switching unit 23: control unit 23a: input terminal 23b: input terminal 23c: input terminal 23d: input terminal 23e: input terminal 23f: input terminal 24: difference calculator 25: changeover switch 25a: contact 25b: contact 26 : PID controller 27: Lead / lag compensation circuit 28: Switching switch H 28a: Contact 28b: Contact 30: Clip base 31: Upper clip lever 32: Lower clip lever 33: Clip lever edge 34: Clip opener 35: Clip closer 36: Clip opener 37: Clip closer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B65H 20/16 B29C 55/20

Claims (9)

(57) [Claims] An absolute position in the web width direction of the tenter clip at a gripping point of the edge of the running web at the tenter clip is detected, and an absolute position of the edge of the web in the web width direction upstream of the gripping point is determined. The web grip amount of the tenter clip at the grip point is determined from the detected absolute position of the tenter clip in the web width direction and the absolute position of the edge of the web in the web width direction, and the web grip amount is determined in advance. A method for manufacturing a web, wherein the web is stretched in the web width direction by the tenter clip while controlling the position of the tenter clip so as to be equal to a set predetermined web grip amount. Detecting a relative position in the web width direction of the edge of the web with respect to the tenter clip near a grip point of the edge of the running web with the tenter clip;
The web gripping amount of the tenter clip is obtained from the relative position, and the web width is controlled by the tenter clip while controlling the position of the tenter clip so that the web gripping amount is equal to a predetermined web gripping amount set in advance. Then, instead of detecting the relative position, the absolute position in the web width direction of the tenter clip at the grip point and the absolute position in the web width direction of the edge of the web upstream of the grip point are determined. The web gripping amount of the tenter clip at the gripping point is determined from the detected absolute position of the tenter clip in the web width direction and the absolute position of the edge of the web in the web width direction. While controlling the position of the tenter clip so as to be equal to a predetermined web grip amount, the tenter clip is controlled. Web manufacturing method characterized by stretching the web in the web width direction by. 3. An edge sensor which is movable in the web width direction when detecting the absolute position of the edge of the web in the web width direction, and edge sensor position detecting means which detects the position of the edge sensor in the web width direction. 3. The method according to claim 1, wherein the absolute position of the edge of the web in the web width direction is detected by the edge absolute position detecting means. 4. The web manufacturing method according to claim 3, wherein said means for detecting the absolute position of the edge further has a power to move the edge sensor. 5. A tenter clip, means for detecting an absolute position in the web width direction of the tenter clip at a gripping point of the edge of the running web at the gripping point of the tenter clip, and a web of an edge of the web upstream of the gripping point. Detecting means for detecting the absolute position in the width direction, detecting output of the absolute position detecting means for the absolute position of the tenter clip in the web width direction, and detecting output of the absolute position detecting means for the edge of the web in the web width direction; A web gripping amount calculating means for calculating a web gripping amount of the tenter clip, a web gripping amount setting means for setting the web gripping amount, and a web gripping amount calculated by the web gripping amount calculating means, wherein the web gripping amount setting means A tenter clip position control means for controlling the position of the tenter clip so as to be equal to the set web grip amount Web manufacturing apparatus characterized by comprising a. 6. A tenter clip, means for detecting the relative position of the edge of the running web in the web width direction with respect to the tenter clip near the gripping point of the tenter clip, and the relative position of the edge in the web width direction. First web gripping amount calculating means for calculating a web gripping amount of the tenter clip at the gripping point from a detection output of a position detecting means; and a web width direction of the tenter clip at a gripping point of the web edge at the tenter clip. Absolute position detection means, Absolute position detection means in the web width direction of the edge of the web upstream of the grip point,
Calculating a web grip amount of the tenter clip at the grip point from the detection output of the absolute position detection means in the web width direction of the tenter clip and the detection output of the absolute position detection means in the web width direction of the edge of the web; Web gripping amount calculating means for selectively transmitting one of an output of the first web gripping amount calculating means and an output of the second web gripping amount detecting means;
Web gripping amount setting means for setting the web gripping amount, and the position of the tenter clip such that the web gripping amount transmitted by the web gripping amount transmitting means is equal to the web gripping amount set by the web gripping amount setting means. And a control means for controlling the operation of the web. 7. The detecting means for detecting the absolute position of the edge of the web in the web width direction comprises an edge sensor movable in the web width direction and an edge sensor position detecting means for detecting the position of the edge sensor in the web width direction. The web manufacturing apparatus according to claim 5, wherein the web manufacturing apparatus is configured. 8. The apparatus according to claim 7, wherein said means for detecting the absolute position of the edge of the web in the web width direction further has a power to move the edge sensor.
2. The web manufacturing apparatus according to claim 1. 9. The apparatus according to claim 5, further comprising means for correcting a web grip amount based on a difference in the web running direction between said edge absolute position sensor and said grip point.
An apparatus for manufacturing a web according to any one of the above.