JPH054896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a simultaneous biaxial stretching device equipped with an endless link device for simultaneously and continuously stretching a plastic film or sheet in two axes, longitudinal and transverse. It is something.

[Conventional technology]

As a conventional simultaneous biaxial stretching device equipped with an endless link device, as described in Utility Model Publication No. 45-6785,
By adding a sprocket to the return side of the link device to provide a link pitch adjustment section, providing a space ring on the link shaft, and bringing each space ring into contact, the driving force is transmitted in the minimum pitch section. The drive power is reduced and the link drive is made smoother. Also, Unexamined Publication No. 59-67015
In this issue, for the purpose of high-speed and stable running, it is proposed to use completely endless rails so that the running trajectory of the linkage device is determined only by restraint by guide rails. This method simplifies the drive system of the conventional method and allows the link device to run at high speed with constant tension applied, but the endless guide rail is different for each section corresponding to film processing. To heat the guide rail to a certain temperature, the guide rail thermally expands from several mm to several tens of mm over its entire length.
On the other hand, since the link device is also heated and cooled to a different temperature than the guide rail, the binding force is relaxed due to the difference in elongation due to mutual thermal expansion, and the guide rail due to the fitting or elongation of each part of the link device that changes over time. No consideration was given to interference with

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration interference and restraint due to the difference in thermal expansion between the link device and the guide rail, and has a problem in that stable operation cannot be performed.

The purpose of the present invention is to smoothly drive a link device restrained by a guide rail, thereby alleviating restraint and interference caused by the difference in thermal expansion between the guide rail and the link device and the elongation of the link device, thereby achieving stable operation. It is about maintaining the state.

[Means for solving problems]

The above object is achieved by adjusting the relationship between the guide rail, the endless link device, and the sprocket that drives the link device to meet limited conditions necessary for stable running of the endless link device.

[Effect]

The endless link device is 1/5 in extension section B.
It is pushed into the inlet side sprocket to the range B,
After that, it is pulled by the outlet sprocket,
In the return section G, it is pushed by the outlet side sprocket to a range of 1/10G, and thereafter it is pulled by the intermediate sprocket, and in the link pitch adjustment section J, it is pushed by the intermediate sprocket to a range of 1/3 to 2/3J, and then Thereafter, it is driven so as to be pulled by the inlet side sprocket, so that restraint and interference due to differences in thermal expansion between the guide rail and the endless link device are alleviated.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In FIG. 1, an unstretched flat film 1 is gripped at both side edges in a gripping section K by a gripping device 3 provided in an endless link device 2, heated in a preheating section A, and then stretched vertically and horizontally in a stretching section B. After being simultaneously stretched in two directions, it is heat-set at a predetermined temperature in a heat treatment section C, and then in a shrinkage section D.
After the film is contracted and cooled in a cooling section E, the film passes through a film separation section F and continues in the direction of the arrow. The endless link device 2 is guided by guide rails 4, 5, and 6, and is driven by procks 7, 8, and 9 provided at both ends. The endless link passes through a return section G, a link pitch adjustment section J, and then returns to a grip section K, forming an endless link device 2.

2 and 3 show details of the endless link device 2. FIG. Both ends of the pair of outer links 12, 13 and the pair of inner links 14, 15 of equal length are connected to the link shaft 1.
The link shaft 16b is meshed with and driven by the aforementioned sprocket, and the link shafts 16a and 16
Bearing rollers 17 and 18 provided at the lower end of b
roll along the grooves formed by the guide rails 4, 6 and 4, 5, respectively. 19 is a roller chain that regulates the maximum pitch of the endless link device 2, and 20 is a space ring attached to the upper part of the bearing rollers 17 and 18.

FIG. 2 shows a state in which each part of the link device 2 is completely opened, and the gripping pitch P of the film 1 is
It is given by Pmax. At this time, the link axis distance H
is Hmin. In this state, the guide rail 4,
5 and 6, the bearing rollers 17 and 18 are constrained to Hmin, and the roller chain 19 is stretched by the sprocket in an unconstrained state. FIG. 3 shows a state in which the bearing rollers 17, 18 are restrained at Hi by the guide rails 4, 5, 6, and the gripping pitch of the film 1 is Pi.

The grip pitch P to be opened in the grip section K is Pmin.
When (H=Hmax), Pmin is a state in which the adjacent space rings 20 are in contact with each other, and the sprocket 8 is driven in a state in which the space rings 20 are pushed. After traveling through preheating section A, stretching section B
Then, due to the regulation of guide rails 4, 5, and 6,
The endless link device 2 travels while gradually opening from the state of Hmax, reaches Hmin at the end of the extension section B, and the gripping pitch P changes from Pmin to Pmax. As a result, the film 1 is stretched in the machine direction (longitudinal direction), and at the same time the guide rails 4,
5 and 6 are set to gradually open in a direction perpendicular to the direction of flow of the film 1, so that the film 1 is simultaneously stretched in the perpendicular direction (lateral direction).
In the heat treatment section C, the film travels after simultaneous longitudinal and transverse stretching has been completed, and in the shrinkage section D, the film gripping pitch P is reduced by only a few percent due to the regulation of the guide rails 4, 5, and 6, and the film is moved to the cooling section E. , a film release section F, a return section G by rotation of the sprocket 9, a link pitch adjustment section J, and a return to the film grip section K, forming an endless link. The relationship between this series of endless link devices 2 and the guide rails 4, 5, 6 is regulated in all sections, and if the link device 2 is always running in a tensioned state in any part, it will cause abnormal interference as described above. In order to solve this problem, large-scale auxiliary equipment such as adding an automatic adjustment mechanism is required. On the other hand, if only a minute interval is provided between the guide rails 4, 5, 6 and the endless link device 2 in each section,
I can't hope for stable running of Film 1. Section A, B,
In C, D, E, F, endless link device 2
is pushed in by sprocket 8 and pulled by sprocket 9, but the position where the pushing force and pulling force change is determined by the distance between sprockets 8 and 9, the link device and quantity between them, and this change point is the upstream side 0 to 1/5B of extension section B,
Preferably, adjust to 1/10B. In the return section G, the endless link device 2 is pushed into the sprocket 9 and pulled by the sprocket 7, but the change point Y between the pushing force and the pulling force is preferably 0 to 1/10 G on the sprocket 9 side in the return section G. is adjusted to 1/50G. In link pitch adjustment section J,
The endless link device 2 is pushed in by the sprocket 7 and pulled by the sprocket 8 while rapidly contracting the link pitch P, but the point Z of change between the pushing force and the pulling force is within the link pitch adjustment section J.
Sprocket 7 side 1/3~2/3J, preferably 3/5J
Adjust to.

Even if sections C, D, and E are not required depending on the purpose of stretching the film, it is best to make the above adjustment.

〔Effect of the invention〕

According to the present invention, by adjusting the minute interval between the endless link device and the guide rail, and by limiting the change point of the pulling force and pushing force of each sprocket, not only the mechanical running condition but also the
This has the effect of allowing the film to run stably.

[Brief explanation of drawings]

FIG. 1 is a plan view of a film simultaneous stretching device showing one embodiment of the present invention, and FIGS. 2 and 3 are detailed plan views of the endless link device. 1...Film, 2...Endless link device, 3...
...Gripping device, 4, 5, 6...Guide rail,
7, 8, 9... Sprocket, 12, 13... Outer link, 14, 15... Inner link, 16a,
16b... Link shaft, 17, 18... Bearing roller, 19... Roller chain, 20... Space ring, X, Y, Z... Change point.

Claims (1)

[Scope of Claims] 1. A plurality of gripping devices for gripping both edges of a thermoplastic resin sheet-like object are provided in an endless link device arranged at both ends of the sheet-like object, and the endless link device is arranged in a folded shape. It is driven by a sprocket on the inlet side of the sheet material, and is guided by a guide rail arranged in a shape that spreads toward the end in the direction of movement to gradually enlarge the gripping pitch. A method for driving a simultaneous biaxial stretching device for a sheet-like object, which is configured to simultaneously stretch the object in both longitudinal and lateral directions, remove the sheet-like object, and return the sheet-like object to the inlet side sprocket by being driven by the outlet side sprocket of the sheet-like object. In this step, the endless link device is pushed by the entrance side sprocket 8 to a range of 1/5B from the entrance of the stretching section B which is formed to widen at the end, and thereafter is pulled by the exit side sprocket 9 to remove the sheet-like material. After that, it is pushed by the outlet sprocket 9 to the range of 1/10G from the outlet sprocket 9 in the return section G from the outlet sprocket 9 to the intermediate sprocket 7 on the inlet side of the sheet material, and after that, it is pulled by the intermediate sprocket 7. In the link pitch adjustment section J between the intermediate sprocket 7 and the inlet side sprocket 8, the intermediate sprocket 7
1. A method for driving a simultaneous biaxial stretching apparatus for a sheet-like material, characterized in that the sheet material is pushed in by an intermediate sprocket 7 to a range of 1/3 to 2/3 J, and thereafter pulled by an inlet sprocket 8.