JPS5914919A - Method of cutting tube - Google Patents

Abstract

PURPOSE:To cut a tube without breaking or creating any wrinkle even if the tube is soft, by inserting a mandrel having a circumferential groove into the tube, holding the outside of the tube by chucks, and rotating a rotating edge so that the rotating edge goes into the groove. CONSTITUTION:The mandrel 1 is inserted into the tube (t) that has been continuously molded, and when an end of a cylinder 5 provided outside of the mandrel 1 comes in touch with an iron piece 6 to cause a contactless switch 7 to be actuated, the chucks 8, 9 are actuated to secure the tube (t) by holding near the opposite sides of the groove 2. Then the rotating cutting edge 3 is rotated once or more about the outer circumference of the tube (t) so that the cutting edge 3 goes into the groove 2. Thus the tube (t) is cut into a desired length. Thereafter when the cutting edge 3 is removed from the groove 2, the chucks 8, 9 are removed, and the mandrel 1 is withdrawn into the cylinder 5, the cut tube (t) is detached from the mandrel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an apparatus for cutting continuously formed tubes into desired lengths. This is a method of cutting tubes that has no cost.

Traditionally, a saw is used to cut PVC resin pipes and profile extrusion molded products, and while this method is suitable for hard molded products, it is not suitable for cutting soft, cheap parts. It is.

Therefore, two main methods have been used to cut relatively soft molded products such as tubes that are mainly made of plastic. In other words, one method is the guillotine cutting method, in which the blade is pressed against the molded product to cut it. In this cutting method, the molded product is crushed when the blade is pressed against it, and the cut end of the tube is cut. There is a problem in that two folds are generated in each case, and the cut surface near the folds becomes a convex surface, making it difficult to achieve perfect straightness and the cut surface is not flat. There are other problems such as difficulty in making the cut surface perpendicular to the tube flow direction. Another method is to roughly cut the cheese using a guillotine method, then insert the cut cheese into a mandrel and cut the cheese to a fixed length by rotating the blade or mandrel. The cutting speed is slow because it is not in-line, but is divided into two processes, and a cutting allowance is required, which is wasteful as the cutting allowance is wasted. In order to increase the processing speed of cutting, it is possible to use this method to cut several pieces of chives at the same time.
There was a problem in that the length of the tube was correspondingly longer and it was difficult to insert and eject it into the mandrel, which was often unreasonable in reality.

As mentioned above, there are problems with conventional cutting methods, but
Since polyethylene tubes have almost no creases, the guillotine method is the most commonly used cutting method. However, recently, in order to improve barrier properties and surface properties, there has been a tendency for extruded tubes to be constructed from a single structure to a multilayer structure, which has caused yet another problem. In other words, for example, when a tube with a two-layer structure using polyamide resin for the outer layer and polyethylene resin for the inner layer is cut using the conventional guillotine method, the tube is bent when the blade is pressed against it, and the polyamide resin of the outer layer is cut. However, since the inner layer of polyethylene resin does not stretch, only the outer layer of polyamide resin remains stretched at the bent part of the product after cutting, leaving wrinkles on the product. In particular, since the tube is continuously molded, if you try to force the tube to stop, fix it at the cutting position, and stabilize the cutting length, you will have to press down on the flexible tube and bend it. In many cases, wrinkles inevitably appeared. Additionally, if the structure contains metal layers such as aluminum foil or hard layers such as high-density polyethylene, not only will wrinkles occur, but also cracks will occur in these hard layers, leading to a decrease in gas barrier properties. This also causes problems.

In response to the above problems, the present inventor has invented a method for cutting a cheap material that does not require an extra cutting allowance and does not cause creases or the like. In other words, in the cutting method of cutting a continuously formed cheep to a desired length in-line, a cutter that is movable in the flow direction of the formed cheep and has grooves in the circumferential direction. By inserting a mandrel inside the tip of the tube being formed and sensing the position of the tip of the tube, the tube and mandrel are pressed and fixed from the outside before and after the two-layer mandrel, and rotated on the outside of the tube. The cut tube is inserted into the groove of the mandrel to cut the tube, the tube is unfixed, and the tip of the tube is pushed out to remove the tube from the mandrel, thereby discharging the cut tube from the line. This is the method for cutting the tube.

Below, a detailed explanation will be given with reference to the drawings.
The figure is a simplified process diagram of the cutting method of the present invention.
In the figure, (1) is a mandrel that is movable in the left-right direction in the drawing, (2) is a groove provided in the circumferential direction of the mandrel (1), and (3) is a mandrel (
1) is a cutting blade that rotates on the outside.

This cutting blade (3) is attached to a rotating ring (4),
Rotate the tube into the center of the mandrel (1) and enter the groove (2) during cutting to cut the tube to the desired length.
- Cut. Now, in the drawing, the cheep (tl) that is continuously formed from the left side pushes the end of the cylinder (5) provided on the outside of the mandrel (1) when the mandrel (1) is inserted. A structure is provided that senses when the tube (5) moves to a certain point, for example, a device that causes the proximity switch (7) to sense when the core comes into contact with one end of the iron piece (6) for position detection. The chucks (8) and (9) that are linked to the function operate to move the tube (tl) into the groove (
2) Press and secure near both sides. Subsequently, the cutting blade (3) approaches the tube country and enters the groove (2) of the mandrel (11) and makes one or more rotations on the circumference of the tube (t), thereby cutting the tube (tl). A tube ttr of desired length is obtained.

(Figure 2). The next step is to remove the cutting blade (3) from the groove (2), remove the chucks (8) and (9), and remove the mandrel (
1) into the tube (5), the cut end of the tube (5) can be removed from the mandrel (1), and the tube (5) itself can be separated from the cutting device. By moving the mandrel (1) and tube (5) to the left, a space is created between the cutting device and the mandrel (1) and tube (5). (Fig. 6).Here, the mandrel (1) is moved to the cylinder (10) by hydraulic pressure or air, and after the cutting and discharging process, the mandrel (1) is moved to the cylinder (10) by hydraulic pressure or air.
0) extends to the right and pushes the mandrel fil back to its original position, the cylinder (5) returns to its predetermined position by the spring (11), etc., and the position detection iron piece (6) also returns to its original position, as shown in Figure 1. will be in the same state.

The present invention has the above configuration, and provides a method for cutting inside a tube that does not require an extra cutting allowance and does not cause creases even in thin and flexible tubes. The mandrel, which is the core, is inserted into the tube and cut by fixing it in a rounded state to prevent double cuts.The cut end of the tube is flat and perpendicular to the length direction inside the tube, and no creases occur. And now it is possible to cut reliably. Also, attach the tube (5) to the mandrel (
By moving the tube along with 1) in the flow direction within the tube, the cut tube can be discharged and the cutting speed can be increased.

Here, in order to prevent the tube from bending between the take-off machine (not shown) and the cutting device, the cutting blade ( 3)
, a cutting device consisting of chucks (8), (9), etc., and a discharging device consisting of a mandrel (1), tube (5), cylinder (10), etc. are moved to follow the tube forming speed, and the tube is quickly discharged after being discharged. Additionally, by returning each device to its original position, the speed of cutting can be further increased. This is particularly effective when the forming speed is high, since the tolerance for temporary slack between the pulling machine and the cutting device is very small when the tube is a thin tube made of polyethylene or the like. Further, when discharging the cut ttl in the chive from the line, more stable cutting can be achieved by forcibly discharging it with air or the like.

[Brief explanation of the drawing]

The drawings show simplified process diagrams of the cutting method of the present invention, in which Fig. 1 shows the process before the tube is inserted into the mandrel, Fig. 2 shows the cutting process, and Fig. 6 shows the process before the tube is inserted into the mandrel. FIG. fl+...Mandrel +21...Groove (3)・
... Cutting blade (4) ... Rotating ring (5) ...
... Cylinder (6) ... Iron piece for position detection (
Sword... Proximity switch (8), (9)... Chat (101... Cylinder (11)...
・Spring (tl...Tube patent applicant Kazuo Suzuki, Representative of Toppan Printing Co., Ltd.

Claims (1)

[Claims] (1) In a method of cutting continuously formed tubes, a mandrel that is movable in the flow direction of the tube being formed and has grooves in the circumferential direction is placed inside the tip of the tube being formed. By inserting the tube and sensing the position of the tip of the tube, the tube and mandrel are pressed and fixed from the outside in front and behind the mandrel,
A method for cutting a cheep, characterized in that the tube is cut by inserting a cutting blade rotating outside the cheep into a groove in the mandrel.