JPH0722962B2 - Film longitudinal stretching machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a longitudinal stretching machine that can be used for longitudinal stretching of plastic films, sheets, tapes and the like.

(Prior Art) FIG. 4 shows a conventional film longitudinal stretching machine, in which 50 is a low speed side frame, 51 is a high speed side frame, and the low speed side frame 50 has take-up rolls 53, 54 for drawing plastic film 52.
Further, a preheating roll 55 provided in a zigzag pattern and a low speed side stretching roll 56 following the preheating roll 55 are provided. On the other hand, the high-speed side frame 51 is provided with a high-speed side stretching roll 57 at a distance L from the low-speed side stretching roll 56, followed by a cooling roll 58 and take-up rolls 59, 60. A film breakage detector 61 is provided between the cooling roll 58 and the cooling roll 58. Further, wheels 62 are attached to the high-speed side frame 51, and the frames 62 can be separated from the low-speed side by rolling the wheels 62 on a rail 64 by the operation of an air cylinder 63 connected thereto. It is like this. The take-up roll 53 to the drawing roll 56 are driven by a low speed side drive motor (not shown),
The parts from 57 to the take-up roll 60 are driven by a high-speed drive motor (not shown).

The stretching plastic film 52 is a take-up roll 53,54.
And is heated by the preheating roll 55, reaches the stretching temperature on the stretching roll 56, is taken up by the high speed side stretching roll 57, and is stretched due to the difference in peripheral speed between the stretching rolls 56 and 57. Then, it is cooled by the cooling roll 58 and taken up by the take-up rolls 59 and 60.

If the film breaks during stretching, the film break detector 61 detects the break and immediately stops the low speed side drive motor according to the command. At the same time, the air cylinder 63 is actuated by a solenoid valve or the like (not shown) to automatically move the high speed side frame 51 on the rail 64 so as to separate it from the low speed side. At the same time, the low speed side take-up roll 54 may be automatically lowered to release the film nip with the take-up roll 53. Further, the moving portion on the high speed side may be only the high speed side drawing roll 57, or may be one part including the drawing roll 57.

(Problems to be Solved by the Invention) In roll stretching of a plastic film, it is widely known that so-called short-section stretching is advantageous, in which the distance between stretching rolls is made as short as possible in order to maintain the uniformity of stretching. .
However, in this case, in order to prevent the film from winding around the low speed side stretching roll at the time of film breakage and damaging the device,
In order to improve the operability of passing the film before the work, it is necessary to open and close the high-speed stretching roll as necessary.

Conventionally, as shown in FIG. 4, the presence or absence of a film between stretching rolls is directly detected by a breakage detector 61 such as a photoelectric tube, and the high speed stretching roll is mechanically opened and closed by an air cylinder or the like. However, with such a structure, the device becomes complicated, and the detection end or the like is provided in the passage of the film, which becomes an obstacle and greatly impairs the speeding of the film threading which is required as the processing speed increases. Furthermore, there is a risk of malfunction due to dirt on the detection end. Therefore, a more reliable and simple mechanism has been demanded.

The present invention aims to provide a film longitudinal stretching machine capable of solving the above-mentioned conventional problems by providing a simple, reliable, and easy-to-handle device.

(Means for Solving the Problems) Therefore, the present invention is a film composed of a low / high speed stretching roll or the like for stretching a belt-shaped material such as a film / sheet heated to a stretching temperature by using a roll peripheral speed difference.・ In a stretching machine for sheets, etc., the stretching force of the high-speed side stretching roll that slides according to the balance between the stretching force of the film / sheet and the self-weight of the movably mounted high-speed side stretching roll is provided, and the stretching force is automatically adjusted. The distance between the stretching rolls is narrowed during the interposition, and the distance between the stretching rolls is expanded when no stretching force is present. This is a means for solving the problem.

(Operation) The fed film or the like reaches the stretching temperature on the stretching rolls, is taken up by the high-speed side stretching rolls, and is stretched between the stretching rolls. At this time, the lever is rotated in the direction of arrow A by the stretching force of the film or the like, and the spacing L between the stretching rolls is maintained. If the film breaks during stretching, the stretching force of the film or the like disappears, so the lever rotates in the direction of arrow B, the stretching roll interval increases to L ₀ , and the low-speed drive motor is stopped.

(Embodiment) The present invention will be described below with reference to embodiments of the drawings, and Figs. 1 to 3 show embodiments of the present invention. First, in FIG. 1, 1 is a frame, and the frame 1 has take-up rolls 3, 4 for drawing plastic film (hereinafter referred to as film) 2
And a preheating roll 5 provided in a zigzag pattern and a low speed side stretching roll 6 following the preheating roll 5, and a high speed side stretching roll 7 is provided at a distance L from the low speed side stretching roll 6 and Subsequently, the cooling roll 8 and the take-up rolls 9 and 10 are provided.

Reference numeral 11 denotes a lever that pivotally supports the high-speed-side stretching roll 7, and is attached to the frame 1 so as to be swingable about a pin 12 attached to the frame 1. And the related dimensions at this time are
During the stretching of the film 2, the rotational force in the direction of arrow A about the pin 12 generated by the stretching force of the film 2 is opposite to the direction of the arrow A about the pin 12 generated by the self-weight of the high speed side stretching roll 7. Is larger than the rotational force in the direction of arrow B, the lever 11 is rotated in the direction of arrow A until the stopper bolt 13 is hit and the gap L is maintained during the stretching of the film 2. The distance L can be adjusted by adjusting the stopper bolt 13 as shown. Also
Reference numeral 14 is a lock nut, and 17 is a bracket attached to the frame 1.

Here, when the stretching force of the film 2 is not interposed between the stretching rolls 6 and 7, the lever 11 rotates in the direction of arrow B until it hits the stopper 15 by its own weight of the high-speed side stretching roll 7,
Allow L ₀ to be held. The take-up roll 3 to the drawing roll 6 are driven by a low-speed drive motor (not shown), and the draw roll 7 to the take-up roll 10 are driven by a high-speed drive motor (not shown). . Further, 16 is a limit switch for detecting that the stretching roll interval has expanded to L ₀ .

Next, the operation will be described. The film 2 is fed by the take-up rolls 3 and 4, heated by the preheating roll 5, reaches the drawing temperature on the drawing roll 6, and is taken up by the drawing roll 7 on the high speed side. And 7 are stretched due to the difference in the peripheral speed of the roll. At this time, the lever 11 is rotated in the direction of the arrow A by the stretching force of the film 2, and the stretching roll interval L
Will be held. Then, it is cooled by the cooling roll 8 and taken by the take-up rolls 9 and 10.

If the film breaks during stretching, the stretching force of the film 2 disappears, the lever 11 rotates in the direction of arrow B, the stretching roll interval increases to L ₀ , and the limit switch 16 is activated to give a command. Stops the low speed side drive motor immediately. At the same time, the low-speed side take-up roll 4 may be automatically lowered to open the nip of the film 2. In addition, as in the case of passing a film, the stretching roll interval is set to L _0.
When the low speed side is driven while being enlarged, a device for canceling the signal of the limit switch 16 is provided as necessary.

In order to open and close the high speed side drawing roll 7 more reliably,
As shown in FIG. 2 and FIG. 3, springs 21 and 31 are mounted between the pins 20 and 30 attached to the frame 1 and the lever 11 to make the above-mentioned operation more reliable, and the pin 12 It is also possible to increase the degree of freedom of the position of. Also springs 21,3
It goes without saying that the force may be applied by another device instead of 1. As described above, the present stretching machine omits the film breakage detector in the vicinity of the film passage and maintains the short stretching interval L during the stretching of the film 2 and maintains the long interval L ₀ during the breaking of the film 2 or during the film passing. It can be held, and safety and operability can be secured with a simple mechanism.

(Effect of the Invention) The present invention is configured as described above in detail, and without placing a film breakage detector in the vicinity of the film passage,
Depending on the balance between the stretching force of the film and the self-weight of the high-speed stretching roll, the stretching roll interval is automatically opened and closed depending on the presence or absence of the stretching force of the film, which reduces the obstacles during the film passing and improves workability. The film can be threaded through. Also, the mechanism is simplified, the reliability of the device is increased, and more reliable operation is possible. Further, the maintenance and inspection of the device can be facilitated, and the device cost can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of a film longitudinal stretching machine showing an embodiment of the present invention, FIGS. 2 and 3 are side views of essential parts showing an embodiment different from FIG. 1, and FIG. It is a sectional side view of a film longitudinal stretching machine. Explanation of main parts of the figure 2 …… Film sheet 6 …… Low speed drawing roll 7 …… High speed drawing roll 11 …… Lever 12 …… Pin 13 …… Stopper bolt 15 …… Stopper 16 …… Limit switch L and L ₀ ...... Stretch roll spacing

Claims (1)

[Claims] 1. A stretching machine for films, sheets, etc. comprising low- and high-speed stretching rolls for stretching a belt-shaped material such as a film, sheet, etc. heated to a stretching temperature by using a roll peripheral speed difference. Equipped with a lever that supports the high-speed stretching roll that slides due to the balance between the stretching force of the sheet and the self-weight of the movably mounted high-speed stretching roll. A film longitudinal stretching machine characterized by expanding a stretching roll interval when no force is present.