JPH1149131A - Plastic case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic case wherein pains are not felt even when a user touches both end corners of a square-cylindrical body part. SOLUTION: This plastic case is constituted of a square-cylindrical body part 10 being formed by bending a synthetic resin sheet which is formed of polyethylene terephthalate and has a certain degree of stiffness, and a lid flap 20 and a bottom flap which are respectively connected to the open end of the body part 10, in order to close the opening. For the lid flap 20, an insertion piece is connected to the tip end, and by inserting the insertion piece into the body part 10, a closed state of the lid flap 20 is kept. Both end corners A of a bent part 11 of the body part 10 are beveled by pressing with a heating jig which is heated to a thermal deformation temperature or higher of the synthetic resin sheet forming this plastic case, and at the tip end parts, a triangular flat surface Sf is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic case in which a body is formed into a rectangular cylindrical shape by bending a plastic sheet.

[0002]

2. Description of the Related Art As shown in FIG. 4, this kind of plastic case is obtained by cutting a plastic sheet having a certain degree of stiffness formed of polyethylene terephthalate or the like into a predetermined shape, and cutting the same. By sequentially bending, a rectangular tubular body 51 is formed, and at both ends of the rectangular tubular body 51,
Usually, a lid flap 52, a bottom flap, and the like for closing the openings at both ends are continuously provided.

As described above, since such a plastic case is formed by bending a plastic sheet having a certain degree of stiffness, the bent portion 51a is rigid, and is shown in FIG. like,
Since the corner portions X at both ends of the bent portion 51a are sharp, a person who handles this plastic case accidentally touches the corner portions X at both ends and feels pain, or has stored a heavy object. Inadvertent handling such as dropping the plastic case onto the foot may cause injury, and the sharp corners at both ends X may damage other articles.

[0004] Further, in a plastic case formed by forming a bent ruled line on a plastic sheet and bending the plastic sheet by the bent ruled line, the corners at both ends of the bent portion become considerably sharp, which is a particular problem. There was a fear.

[0005] Therefore, an object of the present invention is to prevent pain from being felt even when contacting the corners at both ends of the rectangular cylindrical body.
An object of the present invention is to provide a plastic case that does not damage other articles at the corners at both ends.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a plastic case in which a body is formed in a rectangular cylindrical shape by bending a plastic sheet. The corners at both ends of the portion were chamfered by heating and pressing.

[0007] The term "heating and pressing" as used herein means that the corners at both ends are pressed by a heating jig heated to a temperature higher than the heat deformation temperature, or the corners at both ends are previously heated to a temperature higher than the heat deformation temperature by hot air or the like. This is a broad concept including not only pressing with a jig having a predetermined shape in the state, but also blowing the hot air to soften the corners at both ends and pressing the both ends by the wind pressure of the blown hot air.

[0008]

Embodiments will be described below with reference to the drawings. As shown in FIG. 1, this plastic case 1 is made of polyethylene terephthalate and has a somewhat stiff thickness of 0.1 mm to 1.0 mm.
After forming a grooved ruled line at a predetermined position on the synthetic resin sheet, a grooved ruled line having irregularities at the bottom, or a grooved ruled line having an intermittent hole at the bottom, this bent ruled line is formed. And a square cylindrical body 10 formed by bending the synthetic resin sheet, and a lid flap 20 and a bottom flap (sequentially provided at the open end of the body 10 for closing the opening). (Not shown)).

As shown in FIG. 1, the lid flap 20 is provided with an insertion piece 21 at the end thereof.
The lid 1 is inserted into the body 10 to keep the lid flap 20 closed.

As shown in FIG. 2, the corners A and B at both ends of the bent portion 11 of the body 10 are heated to a temperature higher than the thermal deformation temperature of the synthetic resin sheet forming the plastic case 1. By pressing with a jig, the top is deformed and chamfered to form a triangular flat surface Sf at the tip.

As described above, this plastic case 1
Since the ends of the corners A and B are not sharp, a person who handles the plastic case 1 does not feel pain even if the end touches the corners A and B by mistake. A and B do not damage other articles.

At the corner B on the insertion piece 21 side of the lid flap 20, the lid flap 20 is melted or deformed together with the trunk 10, so that the lid flap 20 is
Since it is locally fixed at 0, it cannot be easily opened, and the packaged contents are maintained.

Further, once the plastic case 1 is opened, the original state, that is, the lid flap 20 is
Cannot be returned to the state in which the case is locally fixed, so that there is an effect that it becomes a mark for determining whether or not the case has been opened.

In this embodiment, both end corners A and B
The flat surface Sf is formed at the front end of the base plate. For example, as shown in FIG. You can say that.

In the above-described embodiment, the corners A and B at both ends are chamfered by pressing with a heating jig heated above the thermal deformation temperature of the plastic sheet used. The corners A and B at both ends can be chamfered by pressing with a jig having a predetermined shape in a state where the corners A and B are heated to a temperature equal to or higher than the heat deformation temperature in advance.

Further, when the corners A and B are softened by blowing hot air, the corners A and B can be deformed by the wind pressure of the blown hot air to form the flat surface Sf and the curved surface Sr. Need not press the corner portions A and B with a jig or the like.

Further, this type of plastic case may be formed of a sheet of polyvinyl chloride, polystyrene, polypropylene, polyethylene or the like in addition to the polyester sheet of polyethylene terephthalate as described above. It is effective for plastic cases made of strong polyethylene terephthalate.

Further, as described above, the shape of the plastic case is not limited to a rectangular cylinder having a trunk portion, but may be a rectangular cylinder having a sharp end at both ends. Needless to say, the present invention can be applied to any shape.

[0019]

As described above, in the plastic case of the present invention, the corners at both ends of the bent portion formed in the body are chamfered by heating and pressing. Even if it accidentally contacts the corners at both ends, no pain is felt, and no damage is caused to other articles by the corners at both ends.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment according to the present invention.

FIG. 2 is a partially enlarged perspective view showing a corner portion of the same.

FIG. 3 is a partially enlarged perspective view showing a corner portion according to another embodiment.

FIG. 4 is a perspective view showing a conventional example.

FIG. 5 is a partially enlarged perspective view showing a corner part of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic case 10 Trunk part 11 Bent part 20 Lid flap 21 Insert piece A, B Both ends corner part Sf Flat surface Sr Curved surface

Claims (1)

[Claims] In a plastic case in which a body is formed into a rectangular cylindrical shape by bending a plastic sheet, chamfering is performed by heating and pressing corners at both ends of a bent portion formed in the body. Characterized plastic case.