JP2002254505A - Creased sheet and creasing cutter for plastic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plastic sheet with crease of a novel shape not liable to damage likewise corresponding to an automatic packaging machine when the sheet is used as a packaging container. SOLUTION: The plastic sheet comprises bending crease of groove strips each having a pair of side face and a narrow bottom opposed each other at an oblique predetermined angle. The plastic sheet further comprises one or more lateral grooves each having a narrow bottom formed of two or more curved protrusions in a substantially perpendicular direction with respect to the longitudinal direction of the crease groove and formed in a shape for disposing the lateral grooves at a suitable interval in the longitudinal direction of the crease grooves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic sheet and a ruled blade provided with a grooved ruled line formed by a pair of side and bottom portions which are inclined at a predetermined angle and face each other.

[0002]

2. Description of the Related Art To manufacture a packaging container formed by bending a plastic sheet, a groove 1 for bending is formed on a sheet 1 punched into a shape for assembling the container as shown in FIG. It is bent along the groove 2 to form a packaging container as shown in FIG. The groove 2 is called a “folded ruled line” or simply “ruled line”. The ruled line is formed by pressing a member called “ruled line blade”.

[0003] A method of forming a ruled line and bending it using a ruled line blade is a technique conventionally used for forming a paper container. However, plastic sheets are different from paper in terms of resistance to bending and have high elasticity, so a simple folding ruled line as in the case of paper creates a packaging container with the right angle at the corner. It is difficult.

[0004] In order to solve such a point, various devices have been devised. One is to improve the folding performance by making the shape of the folding ruled line special. For example, Japanese Utility Model Publication No. 4-9345 describes a plastic sheet with a folding line in which irregularities are formed along the longitudinal direction at the bottom of a groove forming the folding line. Japanese Patent Application Laid-Open No. Sho 64-40317 describes a plastic sheet with a folding line in which an intermittent hole is formed at the bottom of a concave groove forming a folding line along the longitudinal direction thereof.

Japanese Patent Laid-Open Publication No. 2-98422 discloses a method of bending a plastic sheet. In folding a plastic sheet provided with a ruled line, after folding the sheet for each ruled line, the sheet is once folded back and then bent. A method is described.

Further, the structure of a ruled line blade for forming a ruled line on a plastic sheet has been devised. JP-A-1-
141720 (patent registration 2542552) has a ruled line blade for plastic sheets, which has a concave and convex shape whose blade edge is interrupted in the length direction, the length of the concave portion is 0.3 to 2 mm, and the length of the convex portion is 0.02 to 0.15 m
m, the width of the tip of the convex part is within 0.5 mm, and the blade angle is 30 ~
A ruled line blade for plastic sheets at 130 ° is described. FIG. 3 shows a perspective view of the ruled line blade. The convex portion 4 of the ruled line blade 3 is sharp, and the concave portion 5 is flat. However, the projection 4 does not necessarily need to have a sharp blade shape.

FIG. 4 shows how a ruled line is formed in a plastic sheet using the ruled line blade 3. The plastic sheet 6 is deformed by the pressing of the ruled line blade, and the ruled line 7 is formed. The groove 8 formed by the projections of the ruled-line blade has little residual material, whereas the groove 9 formed by the concave portion of the ruled-line blade leaves residual material.

[0008]

In the latest automatic packaging machine, a sheet is bent at a high speed to form a three-dimensional container, and the contents are loaded and sealed. Although it has become possible to make folded plastic sheets by creating ruled plastic sheets by various measures as described in the above-mentioned prior art,
It is not fully compatible with this automatic packaging machine. For example, there is a problem that a ruled line portion is torn or formation into a three-dimensional shape fails.

In general, by making the thickness (remaining wall thickness) of the bottom of the groove of the ruled line portion smaller than the thickness of the plastic sheet, the bending characteristics are improved. On the other hand, when the remaining thickness of the ruled line portion is reduced, a strong force is likely to be exerted partially at the time of bending, particularly at the time of assembly and molding by an automatic packaging machine, and there is a problem that the ruled line portion is torn. This problem is particularly likely to occur when the shape of the ruled line is partially provided with a hole in order to facilitate bending.

It is an object of the present invention to obtain a new shape of a ruled line which is not easily damaged when used as a packaging container when a plastic sheet is used as a packaging container.

[0011]

In order to solve the above-mentioned problems, the present invention comprises a folding ruled line of a groove formed by a pair of side surfaces inclined at a predetermined angle and facing each other and a narrow bottom surface. In a plastic sheet, one or more transverse grooves having at least one narrow bottom surface formed by two or more curved protrusions in a direction substantially perpendicular to the longitudinal direction of the ruled line groove are arranged at appropriate intervals in the longitudinal direction of the ruled line groove. Form.

Further, in order to form such a ruled line, the ruled line blade is inclined with respect to a normal ruled line blade (vertical blade) which is inclined at a predetermined angle and has a pair of side surfaces facing each other and a narrow top surface. It is assumed that two or more curved concave portions are provided close to each other in a direction perpendicular to the cutting edge portion, and a boundary portion between the curved concave portions forms a horizontal blade.

A plastic sheet has a higher elastic force than paper, and a ruled line formed on paper may return to its original state even if it is bent, even if it is bent.
Therefore, when a shape such as a container is formed, the shape may be lost. Therefore, how to insert the ruled line is an important factor in forming a container that does not lose its shape, and it is important to design a folded ruled line according to the material of the plastic sheet.

In the ruled line according to the present invention, the residual wall formed by the horizontal blade and the curved concave portion functions to suppress this elastic force. further,
The combination of the number of curved concave portions and the vertical blade has an advantage that a ruled line blade can be designed for any material.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is an explanatory view showing a state in which the ruled plastic sheet of the present invention is viewed obliquely from the upper front side. A ruled line 11 is provided on the plastic sheet 10. The lateral groove is a bottom portion 1 extending in the longitudinal direction of the ruled line groove.
2, a shallow and short bottom surface portion 13 is provided at substantially equal intervals in a direction substantially perpendicular to the direction. The width of the bottom is determined by the size and material of the plastic sheet.

As the material of the plastic sheet, a single or composite sheet of polyethylene terephthalate, polyvinyl chloride, polypropylene or the like is used. Usually, those having a thickness of about 0.1 mm to 1.0 mm are used. A tool for folding the plastic sheet to form a ruled line is a ruled line blade. Depending on the material and thickness of the plastic sheet, the strength of the ruled line portion can be changed depending on the combination of the vertical blade, the horizontal blade, and the curved concave portion of the ruled line blade and the depth of each combination.

FIG. 6 is a perspective view of a ruled line blade for forming the ruled line groove shown in the above example. The ruled line blade in the figure is a combination of a vertical blade 14, a curved concave surface 16, and a horizontal blade 15.
The vertical blade 14 is a blade provided in the direction of a ruled line blade (a cutting edge direction), and the horizontal blade 15 is a blade provided in a direction substantially orthogonal to the direction of the ruled line blade. Since the horizontal blade 15 is present at a position deeper than the vertical blade 14, the ruled line carved by the horizontal blade 15 has thicker residual material than the vertical blade 14 remaining on the plastic sheet.

FIG. 7 shows an example of a ruled line blade according to another embodiment of the present invention. In this example, two horizontal blades 15 are arranged continuously. Adjust the number and position of the horizontal blades according to the material and thickness of the plastic sheet.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment shown in FIGS. 8 and 9 of a ruled line blade for cutting a bending line of a plastic sheet will be described. In addition,
This figure is not drawn to scale in proportion to actual conditions. As shown in FIG. 8, the ruled line blade has a blade height of 0.6 mm and a blade thickness of 1.0 mm. FIG. 9 is a view of the blade viewed from the side. The pitch of the horizontal blade is 1.1 mm, and the interval between the deepest parts of the curved concave
0.25mm.

The height of the blades, the pitch of the horizontal blades, the number of horizontal blades, and the like can be changed depending on the thickness and material of the sheet. Therefore, it is clear that the present invention is not limited to the data of this embodiment.

[0021]

A feature of the present invention is that the folding ruled blade according to the present invention can easily be designed with a ruled line blade corresponding to the material of the plastic depending on how to form the curved concave portion. Further, since the vertical blade and the horizontal blade can be automatically formed only by forming the curved concave portion, it is easy to manufacture the ruled line blade.

The plastic sheet had elasticity. Depending on how the folding ruled line is inserted, the elastic force may return to the original state even when bent. Therefore, when a shape such as a container is formed, the shape may be lost. Therefore, how to form the ruled line is an important factor in forming a container that does not lose its shape. For that purpose, it is important to design the folding ruled line according to the material of the plastic sheet. In the ruled-line blade of the present invention, the residual wall formed by the horizontal blade and the curved concave portion functions to suppress this elastic force. Further, there is an advantage that a ruled line blade that can be used for any material can be designed by a combination of the number of curved concave portions and the vertical blade.

With the ruled line blade of the present invention, it is easy to design a ruled line blade suitable for various plastic sheet materials. The ruled-lined plastic sheet of the present invention has an effect that partial damage is less likely to spread because the bottom portions of the ruled line grooves, which are the center of folding, are not simply arranged in one line. As a result, the effect of reducing the incidence of breakage accidents was obtained even in automatic packaging equipment in which relatively strong bending force works.

Since the curved concave side surface is a curved surface, sharp corners in the ruled line grooves formed in a plastic sheet shape are reduced, so that light scattering is small and folds are less noticeable.
A transparent container excellent in appearance can be formed.

Further, the shape of the fold becomes complicated, the ruled line portion does not return due to the elastic force of the plastic sheet, there is little losing of the shape at the time of processing, and the range of adjustment by the material is changed, such as changing the number of horizontal blades. There are effects such as wide.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which a plastic sheet for a packaging container with a folding ruled line is developed.

FIG. 2 is an explanatory view of assembling a plastic sheet with folded ruled lines for packaging.

FIG. 3 is an explanatory view showing a structure of a conventional folding ruled line blade.

FIG. 4 is an explanatory view showing a folding ruled line put in a plastic sheet by the conventional ruled line blade shown in FIG. 3;

FIG. 5 is a front oblique view of an example of a ruled plastic sheet according to the present invention.

FIG. 6 is a perspective view of an example of a ruled line blade of the present invention.

FIG. 7 is a perspective view of an example of a ruled line blade of the present invention.

FIG. 8 is a sectional view of a ruled line blade according to the embodiment of the present invention.

FIG. 9 is a side view of the ruled line blade according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic sheet 2 Groove 3 Ruled line blade 4 Convex part 5 Concave part 6 Plastic sheet 7 Ruled line 8 Groove part 9 Groove part 10 Plastic sheet 11 Ruled line 12 Bottom part extended in the longitudinal direction of ruled line 13 Bottom part of shallow short groove 14 Vertical blade 15 Horizontal blade 16 Curved concave surface

Claims (2)

[Claims] 1. A plastic sheet provided with a groove ruled line formed by a pair of side surfaces and a narrow bottom surface that are inclined at a predetermined angle and face each other, wherein the plastic sheet is formed in a direction substantially perpendicular to the longitudinal direction of the groove. A folded crease-filled plastic sheet wherein at least one lateral groove having a narrow bottom surface formed by the above-mentioned curved convex portion is formed at an appropriate interval in the longitudinal direction of the crease groove. 2. A conventional ruled-line blade (vertical blade) having a pair of side surfaces inclined at a predetermined angle and facing each other and a narrow top surface, is provided with two or more curved concave portions in a direction perpendicular to the cutting edge. A ruled line blade for a plastic sheet, wherein the ruled line blade is provided in close proximity, and a boundary portion of the curved concave portion forms a horizontal blade.