JPH0252616B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet-like object stretching device using a stretching link device capable of stretching a sheet-like object, such as a thermoplastic synthetic resin film, in the longitudinal direction (longitudinal direction) and/or in the lateral direction. It is something.

Figure 1 is Utility Model Publication No. 6785, Special Publication No. 1978-
39478, etc.; FIG. 2 is an enlarged plan view showing a link device capable of simultaneous biaxial stretching by configuring two types of long and short links in a pantograph shape; FIG. FIG. 2 is a plan view showing the entire stretching device.

In the stretching device shown in FIG. 2, the link device 2 shown in FIG. 1 is connected endlessly, and the sprocket 7,
8 and 9 are continuously driven. The movement of the link device is regulated by guide rails 4, 5, 6 arranged at both ends of the film 1. The intervals between the guide rails 4 and 5 and between the guide rails 4 and 6 are film gripping section C, preheating section D, heat treatment section F,
In the film release section G and return section H, they are parallel, and in the stretching section E, the film travel direction A
In the pitch reduction section B, the pitch becomes wider as it goes toward the sprocket 8.

Due to the arrangement of the guide rails, the film is continuously flowing in the direction A, and the gripper 3 attached to the link device 2 is held in the film gripping section C.
Both ends of the film are gripped by the gripper, and in the gripped state, the film is preheated in a preheating section D, stretched simultaneously in the vertical and horizontal directions in a stretching section E, heat treated in a heat treatment section F, and released from the grippers in a film release section G. Ru. After the film is released, the link device 2 passes through a return section (longest gripper pitch section) H and then a pitch reduction section B, in which the longest gripper pitch is set as the initial minimum gripper pitch.

The above movement of the link device 2 is caused by the rollers 17 and 18.
However, if all the rollers of the endlessly connected link device are in contact with the guide rails, a large force that cannot be realized due to the boosting effect Sprocket driving force is required.

Therefore, in Japanese Utility Model Publication No. 45-33903, etc., by driving the maximum link pitch (longest grip pitch) section with a roller chain (short link), the friction between the link device and the guide is reduced, the driving force is reduced, and the smooth It allows you to do some exercise.

In such a device, in the section where the gripper pitch is the longest, the short links 19a and 19b in FIG.
is extended and becomes a straight line, and the short links 19a, 1
Since 9b becomes a pick-up bar, rollers 17 and 18
It is mechanically impossible to reduce the gripper pitch by contact between the guide rails 4, 5, and 6.

For this reason, as shown in Fig. 2, a pitch reduction section B is provided at the outlet of the sprocket 7, and the connecting pins 16a and 16b of the short links are all engaged with the sprocket 7, thereby creating an intersection angle between the short links 19a and 19b. After attaching the rollers 17 and 18
The grip pitch can be reduced by the contact between the guide rails 4, 5, and 6.

In this case, the maximum intersecting angle at which the grip pitch can be reduced is determined by the complex contribution of the pairwise friction between all the links constituting the link device and the link connecting members.

Next, we will discuss the problems with the conventional device.

Figure 3 shows a pin 16 that is a short link connecting member.
16b is an enlarged plan view showing the meshing relationship between the link device and the sprocket, showing a state in which the sprockets a and 16b are all engaged with the sprocket 7. If R and the length of the short link are l, it is determined by ψ=2×COS ^-1 (l/2R). If you want to obtain a small crossing angle in order to facilitate the reduction of the gripper pitch in the pitch reduction section B, the only way is to increase the length l of the short link or decrease the sprocket radius R according to the above formula. do not have.

However, there is a limit to increasing the length of the short links because the maximum gripper pitch increases, causing wrinkles in the film and poor stretching.

On the other hand, if the sprocket radius is made small, the rotation radius at the sprocket part of the linkage is small, which causes large fluctuations in acceleration, making it impossible to expect smooth motion at high speeds, and furthermore, the dead weight receiver that supports the linkage becomes more abrasive. Therefore, it is difficult to maintain and is not suitable for speeding up.

The purpose of the present invention is to eliminate the above-mentioned defects of the prior art, to reduce the intersecting angle of the short links, to easily reduce the grip pitch, to enable high-speed driving, and to reduce the wear of the self-weight bearing. It is an object of the present invention to provide a sheet-shaped material stretching device that reduces the number of defects and makes its maintenance easier.

In order to achieve the above object, the present invention has the following configuration.

That is, it is composed of an endless chain link in which a plurality of links are arranged in a pantograph shape so that they can be bent and extended with each other, and connected in an annular manner. a stretching mechanism in which long links are arranged adjacent to each other and a gripper is provided on the pantograph link member unit;
In a sheet-like material stretching device equipped with a plurality of sprockets for driving the mechanism and a pair of left and right guide rails for guiding the mechanism, the short link of the pantograph link is connected to the pitch reduction section following the longest gripper pitch section. This is a sheet-shaped material stretching device characterized by being provided with a sprocket into which every other member is bitten.

Hereinafter, the present invention will be explained using examples and with reference to the drawings.

FIG. 4 is an enlarged plan view showing the meshing relationship between the link device and the sprocket according to the present invention. Only the sprocket 16a is shown being engaged with the sprocket 7, and FIG. 5 is a sectional view taken along the line AA in FIG. 4.

In FIG. 4, the sprocket 7 is provided at the starting point of pitch reduction from the longest gripper pitch. A notch 24 is provided in the sprocket 7 so that the pin 16b, which is not engaged with the teeth of the sprocket 7, does not interfere with the sprocket.

When the link device is engaged with the sprocket, the short links 19a and 19b on both sides are aligned in a straight line with the unengaged pin 16b in the center (see Fig. 4), and the pin 1
The meshing of the pin 16a with the sprocket is adjusted so that the pin 16a does not behave unstablely. In addition,
At the outlet of the sprocket, the link device can freely rotate around the pin 16b that is not engaged with the sprocket, so there is no problem even if the short links are aligned in a straight line in the above condition.

Guide rails are provided in the rotating portion of the sprocket to prevent the link device from flying out from the teeth of the sprocket due to centrifugal force during high speed rotation. Further, at the outlet of the sprocket, guide rails 4, 5, and 6 are provided whose spacing gradually becomes wider in the direction of travel, thereby reducing the grip pitch.

Next, the operation and function of this device will be explained.

According to the stretching device to which the present invention is applied, the intersection angle of the short links is determined by ψ=2×COS ⁻¹ (l×R).

On the other hand, when the pin connecting the short links of the link device is caught in the sprocket as in the prior art, the crossing angle is determined by ψ=2×COS ^-1 (l/2R).
If the same link device is used, the short link length l is naturally the same, and the maximum crossing angle required to reduce the gripper pitch is also the same, so the method according to the present invention is twice as effective as the conventional method. This means that a sprocket with a radius of .

The above description shows one embodiment of the present invention, and the present invention is not limited to the link device shown in FIG. It can also be applied to a conventional stretching device.

The sprocket 7 is preferably provided at the starting point of pitch reduction from the longest gripper pitch, but may be provided in other pitch reduction sections. Furthermore, as shown in FIG. 5, one sprocket 7 is provided at the center of the connecting pin 16b, but a plurality of sprockets 7 may be provided at the same position in the vertical direction. Furthermore, a stretching device to which the above link device is applied can be used not only as a biaxial stretching device but also as a longitudinal or lateral stretching device. Furthermore, the invention can also be applied to a link device in which a roller 25 is attached to a pin connecting short links, as shown in FIG. 6, in order to ensure smooth engagement with a sprocket.

Since the present invention has the above-described configuration, it has the following excellent effects.

That is, if the linkage is the same, the present invention can use a sprocket with twice the radius of the conventional one to obtain the same crossing angle, so that even at high speeds the movement of the rotating parts is reduced. This makes maintenance easier because there is less wear on the weight bearing of the link device. Furthermore, the grip pitch of a high-speed sheet stretching device can be easily reduced.

[Brief explanation of drawings]

Figure 1 is an enlarged plan view of a pantograph-like link device using two types of long and short links;
The figure is a plan view showing the entire stretching device, and FIG.
Figure 4 is an enlarged plan view of the sprocket when all the pins connecting the short links of the link device are caught in the sprocket. FIG. 5, an enlarged plan view of the sprocket according to the invention, is a cross-sectional view taken along the line AA in FIG. 4. 6th
The figure is a sectional view showing another embodiment according to the present invention. Explanation of symbols in the drawings: 1: Film, 2: Link device main body, 3: Grip, 4, 5, 6: Guide rail, 7, 8, 9: Sprocket, 10, 1
1: Grip guide, 12, 13, 14, 1
5: Long link, 16a, 16b: Short link connecting member, 17, 18: Guide roller, 19a, 19
b: Short link, 20: Extension link, 21: Spring,
22: Weight bearing, 23: Link connection pin, 24:
Notch part, 25: roller.

Claims (1)

[Claims] 1 Consisting of an endless chain link in which a plurality of links are arranged in a pantograph shape so that they can be bent and extended with each other, and connected in an annular manner, the lengths of the link members on the four sides constituting the pantograph member unit are two types, long and short, and the lengths are the same. It is equipped with a stretching mechanism in which links are arranged adjacent to each other and grips are provided on the pantograph link member unit, a plurality of sprockets for driving the mechanism, and a pair of left and right guide rails for guiding the mechanism. A sheet-like material stretching apparatus, characterized in that a sprocket is provided in a pitch reduction section following the longest gripper pitch section, into which every other short link connecting member of the pantograph link is engaged.