JPH11147253A - Plastic case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flatness of a plastic case after it is assembled by a method wherein bending stresses can be dispersed and absorbed by three parallel lines so that the case can be easily bent and residual stresses are decreased and hence bending angles, when the case is assembled, can be precisely formed. SOLUTION: Lines 31, 32, each having a groove shape in cross section, are formed on one surface of a plastic sheet 2, while a line 33 having a groove shape in cross section is formed on the other surface of the sheet 2 so as to correspond to an intermediate line between both the lines 31, 32, whereby a plastic sheet having a bending line 1 comprising the lines 31, 32, 33 is provided. The plastic sheet is then bent along the line 1 so that the lines 31, 32 are positioned on the inner side of the sheet to constitute a plastic case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic case formed by bending a plastic sheet with a folding line.

[0002]

2. Description of the Related Art A plastic sheet is bent and processed.
When processing into plastic cases such as doll cases, packaging containers, etc., attach bending lines to the plastic sheets,
It is bent along this. As shown in FIGS. 3A, 3B and 3C, a plastic sheet with a folding line, which is a constituent material of a conventional plastic case, has a concave groove shape in which only one surface of the plastic sheet 2 is recessed in the thickness direction. One or a plurality of ruled lines 3 are provided, or a bent sheet formed by providing a pair of ruled lines 3 at corresponding positions on the front and back of the plastic sheet 2 is used.

[0003]

The above-mentioned plastic sheet with a fold line, which is a constituent material of the conventional plastic case, does not have sufficient foldability, so that it cannot be finished at a predetermined angle when it is bent, or after the processing. There is a problem that the plane is easily curved due to the residual stress, and when a pair of ruled lines 2 are provided on the front and back, it is difficult to adjust the depth of the ruled line, and there is a problem that the bending easiness is unstable. It was difficult to obtain a plastic case with an accurate bending angle and good flatness.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to improve the foldability of a plastic sheet with a fold line and to provide a plastic case having an accurate fold angle and good flatness. It will be described based on.

FIG. 1 is a perspective view of one portion showing an example of a plastic sheet with a fold line as a constituent material of the plastic case of the present invention. FIG. 2 is another example of a plastic sheet with a fold line and an apparatus with a fold line. FIG. 3 is a partial sectional view showing one example, and FIG. 3 is a partial sectional view showing one example of a conventional plastic sheet with a folding line.

According to the present invention, a plastic sheet is formed without curving the front and back surfaces of the bending line forming section and making the thickness of the bending line forming section smaller than the thickness of the plastic sheet 2 as shown in FIGS. 2, two concave grooved ruled lines 31 and 32 provided with one surface depressed, and the other surface of the plastic sheet 2 at a position corresponding to an intermediate position between these two grooved ruled lines 31 and 32 are concaved. A plastic sheet with a fold line provided with a fold line 1 consisting of a single groove grooved ruled line 33 provided so that the two grooved ruled lines 31 and 32 are located inside. The present invention relates to a plastic case characterized in that the bending line 1 is bent.

As the plastic sheet 2, a rigid sheet such as polyvinyl chloride or polypropylene can be used.

[0008] The bending line 1 is formed within the thickness of the plastic sheet 2 as described above, and is formed with two lines on one surface and one line on the other surface, both of which are recessed from each surface. It is composed of a total of three ruled lines, and the bending stress is dispersed by the three ruled lines. In addition,
The bending direction is effective in both cases,
It is easier to bend the book with the ruled lines 31, 32 inside.

Since each ruled line is formed so as to be depressed within the thickness of the plastic sheet 2, the folding line 1 is finished thinly, and the ruled lines on both sides are displaced from each other. Despite being formed, the narrow pressure is not concentrated at the time of forming the ruled line, and the thickness does not become too thin.

The ruled lines 31, 32, and 33 may be arranged so close that the bent lines do not become wide enough to adversely affect the appearance, and the depth is usually preferably 5 to 50% of the thickness of the plastic sheet 2.

The above-mentioned plastic sheet 2 with bending lines
For example, as shown in FIG. 2, a ruled line blade 4 having two cutting edges 41 and 42 corresponding to two ruled lines 31 and 32 and a position corresponding to an intermediate position between the cutting edges 41 and 42 are required. The plastic sheet 2 having the folding lines 1 with the ruled lines 31, 32, 33 provided by narrowing the pressure between the blade 5 and the receiving table 5 having the protruding edge 53 is obtained. The ruled line blade 4 and the cradle 5 are roll-shaped and the blade edges 41, 42, 53
May be provided.

[0012]

【The invention's effect】

As described above, the plastic case of the present invention corresponds to the two concave grooved ruled lines provided by recessing one surface of the plastic sheet, and the middle between these two concave grooved ruled lines. A plastic sheet with a folding line provided with a folding line composed of one grooved ruled line provided by recessing the other surface of the plastic sheet at the position is used, and the two grooved ruled lines are formed on the inner side. Since the bending line is bent in such a manner, the bending stress applied to both sides of the plastic sheet is dispersed and absorbed by the three ruled lines, so that it is easy to bend. Since the residual stress is small, a plastic case such as a doll case or a folding box is assembled. In this case, the bending angle becomes accurate, and the flatness after assembly is good. Also, since the ruled lines on both sides are displaced from each other, the narrow pressure is not concentrated when the ruled line is installed and the thickness is not too thin even when formed within the thickness of the plastic sheet. doing.

[Brief description of the drawings]

FIG. 1 is a perspective view of one portion showing an example of a plastic sheet with a folding line, which is a constituent material of a plastic case of the present invention.

FIG. 2 is a partial cross-sectional view showing another example of a plastic sheet with a folding line, which is a constituent material of the plastic case of the present invention, and an example of a folding line attaching device.

FIG. 3 shows a conventional plastic sheet with a folding line.
Partial sectional view showing an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bending line 2 Plastic sheet 3,31,32,33 Ruled line

Claims (1)

[Claims] 1. Two concave portions provided without curving the front and back surfaces of the folding line forming portion, making the thickness of the folding line forming portion smaller than the thickness of the plastic sheet, and recessing one surface of the plastic sheet. Grooved ruled lines and these two
A plastic sheet with a folding line provided with a folding line composed of one grooved ruled line provided by recessing the other surface of the plastic sheet at a position corresponding to the middle of the grooved ruled lines, A plastic case, wherein the bending line is bent so that the two grooved ruled lines are on the inside.