JP2001277342A - Plastic molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plastic molded object having a hinge part which is bent lightly, generates no excessive strain load even partially by the repetition of bending and has excellent durability. SOLUTION: The main body 2 and lid member 3 of a container being two constitutional parts are connected by the thin-walled hinge part 4 integrated with both of them. A large number of grooves 6 are formed to the hinge part 4, which is molded by compressing a part of a parison in the compression part of a mold to reduce the wall thickness thereof, in the direction crossing the bending direction of the hinge part at a right angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molded body, such as a container body and a lid, or a rear parcel shelf of an automobile, wherein two components are connected to each other by a thin hinge part formed integrally therewith. .

[0002]

2. Description of the Related Art A plastic container which is a plastic molded article of this kind can be manufactured by blow molding as described in, for example, Japanese Patent Application Laid-Open No. 62-158637 or Japanese Patent Application Laid-Open No. 62-85924. A split mold consisting of one half mold and the other half mold is used as the blow molding mold, but the two components of the plastic container, the main body and the lid, are integrated with them. In order to blow-mold a product formed by connecting thin hinge portions, a compression portion forming a hinge portion is provided between a cavity for molding the main body and a cavity for molding the lid.

[0003]

SUMMARY OF THE INVENTION The above-mentioned JP-A-62-1
As described in Japanese Patent No. 58637 or JP-A-62-85924, a compression portion for forming a hinge portion is provided between a cavity for molding a main body and a cavity for molding a lid, and the mold is closed at the time of mold clamping. The part that becomes the hinge part of the parison is compressed and thinned.However, even if the pressure at the time of mold clamping is set sufficiently large for the whole mold, the compression pressure applied to the compression part that forms the hinge part increases as the compact to be molded becomes larger. It is not uniform, a part of the hinge part does not become an appropriate thickness as a hinge, and a phenomenon that a resin swells partially is known from the past, and from this, bending failure occurs in the hinge part, It has also been pointed out that a problem such as a deterioration in durability is caused.

Incidentally, in a plastic molded body such as the plastic container, it is preferable that the thickness of the hinge portion is approximately 0.3 to 0.6 mm. Such a thickness of the hinge portion varies depending on the type of the resin, but in general, if the thickness of the hinge portion is less than 0.3 mm, the required strength as a hinge cannot be maintained, and the thickness differs slightly depending on the type of the resin. If it exceeds 0.6 mm, the bending of the hinge may fail, especially if the component part connected to the hinge part is as small as a small lid, even if it is closed, it is flipped back in the opening direction and opened carelessly. There is a disadvantage that it will. In addition, it is known that when the interval between the compression parts at the time of mold clamping of the mold is set to 0.2 mm, the hinge part has an appropriate thickness of 0.35 to 0.55 mm.
As described above, when the size of the molded body becomes large, the thickness of the hinge portion exceeds 0.6 mm, and the function of the hinge is impaired.

[0005] Therefore, the present invention provides a method for compressing a parison in a compression part of a mold, even if a plastic molded body in which two components are connected by a thin hinge part integral with them is large. By forming a large number of grooves in a direction perpendicular to the bending direction on the hinge part formed by compressing and thinning the part, the hinge part can be bent easily by the plurality of grooves, and It is an object of the present invention to obtain a plastic molded body having a hinge part excellent in durability, in which a part is not subjected to an excessive strain load due to repeated bending.

[0006]

In order to achieve the above object, an invention according to claim 1 is a plastic molded article comprising two components connected by a thin hinge portion which is integral with them. The present invention relates to a plastic molded article characterized in that a number of grooves are formed in a direction perpendicular to a bending direction as a hinge.

According to a second aspect of the present invention, in the plastic molded body according to the first aspect, the plastic molded body formed by connecting the two constituent parts with a thin hinge portion integral with the plastic molded body is blow molded. It is characterized by being.

[0008] The invention described in claim 3 is claim 1 or 2.
In the plastic molded article described above, the concave groove formed in the hinge portion is continuous in a direction orthogonal to the bending direction as the hinge, and has a triangular cross-sectional shape.

According to a fourth aspect of the present invention, in the plastic molded body according to the first, second or third aspect, the hinge portion has a groove formed on one surface thereof.

According to a fifth aspect of the present invention, in the plastic molded body according to the first, second, or third aspect, the hinge portion is formed with concave grooves on both surfaces thereof.

According to a sixth aspect of the present invention, in the plastic molded body according to the fourth aspect, the hinge portion has a thickness of 0.4 to 0.4.
0.8 mm, and the depth of the concave groove is 0.1 to 0.4 mm.

According to a seventh aspect of the present invention, in the plastic molded body according to the fifth aspect, the thickness of the hinge portion is 0.45.
~ 1.0mm, the depth of the groove is 0.1 ~ 0.4mm
It is characterized by being.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention. FIG. 1 is an overall perspective view of a plastic container which is an example of a plastic molded article according to the present invention, FIG. 2 is a detailed plan view of a portion surrounded by a dashed circle A in FIG. 1, and FIG. FIG. 4 is a perspective view of a rear parcel shelf of an automobile as another example of the plastic molded article according to the present invention.

1 to 3, reference numeral 1 denotes a plastic container. The plastic container 1 is composed of a container body 2 and a lid 3 which form two components, and the body 2 and the lid 3 are connected by a thin hinge part 4 which is integral with them. On the other hand, the lid 3 can be opened and closed freely. Reference numeral 5 denotes a handle. The plastic container 1 is made of blow molded thermoplastic resin and has a main body 2.
The cover 3 has a hollow double-walled structure, and the hinge 4 is formed integrally with the main body 2 and the cover 3 by compressing and thinning a part of the parison when the mold is clamped by a mold.

As shown in detail in FIGS. 2 and 3, the hinge portion 4 is formed by forming a large number of grooves 6 in a direction perpendicular to the bending direction as a hinge. The concave groove 6 to be formed is continuous in a direction orthogonal to the bending direction as a hinge, that is, in a direction along a side connected to the hinge portion 3 of the main body 2 and the lid 3, and has a triangular cross-sectional shape. I have. The groove 6 is not necessarily continuous, but may be formed intermittently.

In the embodiment shown in FIGS. 1 to 3, a concave groove 6 is provided on one side of the hinge portion 4, that is, on the inside of the bent portion.
However, a concave portion may be formed on both sides of the hinge portion (not shown). In the case where the concave groove 6 is formed on one surface of the hinge 4, the thickness of the hinge 4 is set to be equal to or less than 0.1.
4 to 0.8 mm, and the depth H of the concave groove 6 is 0.1 to 0.1 mm.
4 mm. In the case of forming a concave groove on both sides of the hinge, the thickness of the hinge is 0.45 to 1.0 mm, and the depth of the concave is 0.1 to 0.4 mm.

As another example of the plastic molded article according to the present invention, a rear parcel shelf 7 of an automobile shown in FIG.
The one panel part 8 and the other panel part 9 are connected to the hinge part 1.
Reference numerals 11 and 11 denote shafts fixed to the vehicle body, and 12 denotes a handle. Also in this rear parcel shelf 7, the hinge portion 10 has the same configuration as the hinge portion 4 of the plastic container 1, and can adopt the same embodiment. The rear parcel shelf 7 is also blow-molded, and one panel 8 and the other panel 9 have a hollow double wall structure.

The plastic container 1 which is a plastic molded product according to the present invention or the rear parcel shelf 7 of an automobile is made of a blow moldable resin such as ABS resin, modified polyphenylene oxide resin, polycarbonate resin, polyamide resin, polypropylene resin or polyethylene resin. It is composed of a plastic resin.

In the plastic container 1 constructed as described above, the main body 2 and the lid 3 are connected to each other by the thin hinge portion 4 which is integral with them, and in the rear parcel shelf 7 of an automobile, One panel 8 and the other panel 9
Are connected by a thin hinge portion 10 integral with them, even if the plastic container 1 or the rear parcel shelf 7 is large, a part of the parison is compressed and thinned by the compression portion of the mold. Since the hinge portions 4 and 10 formed into a plurality of sections are formed with a large number of grooves 6 in a direction perpendicular to the bending direction, the hinge sections 4 and 10 are easily bent by the multiple grooves 6. The bending of the hinge portions 6 and 10 does not cause an excessive strain even in part, and the plastic container 1 or the rear parcel shelf 7 of the automobile is excellent in durability.

According to the experiment of the inventor, the hinge portions 4
In the case of forming the concave groove 6 on one surface of the hinge 10, the hinge portion 4,
It is most preferable from the viewpoint of the function of the hinge that the thickness of the groove 10 is 0.4 to 0.8 mm and the depth H of the concave groove 6 is 0.1 to 0.4 mm. Further, in the case where concave grooves are formed on both surfaces of the hinge portions 4 and 10, the thickness of the hinge portions 4 and 10 is 0.45.
~ 1.0mm, the depth of the groove is 0.1 ~ 0.4mm
Is equally preferred.

[0021]

According to the present invention, even if a plastic molded body formed by connecting two components with a thin hinge portion integral with them is large, the parison can be formed by the compression portion of the mold. By forming a plurality of grooves in a direction orthogonal to the bending direction in a hinge part formed by compressing and thinning a part of the hinge part, the hinge part is bent easily by the plurality of grooves. In addition, an excessive strain load is not generated in the hinge part even by repeated bending, and a plastic molded body having a hinge part excellent in durability can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a plastic container as an example of a plastic molded product according to the present invention.

FIG. 2 is a detailed plan view of a portion surrounded by a dashed circle A in FIG. 1;

FIG. 3 is a detailed sectional view showing a part corresponding to FIG. 2;

FIG. 4 is a perspective view of a rear parcel shelf of an automobile, which is another example of the plastic molded article according to the present invention.

DESCRIPTION OF SYMBOLS 1 Plastic container 2 Main body 3 Lid 4 Hinge part 5 Handle part 6 Concave groove 7 Rear parcel shelf 8 One panel part 9 The other panel part 10 Hinge part 11, 11 Fixing shaft to vehicle body 12 Handle part

Claims (7)

[Claims] 1. A plastic molded body in which two components are connected by a thin hinge part integrally formed with the two parts, wherein a plurality of concave grooves are formed in the hinge part in a direction orthogonal to a bending direction as a hinge. A plastic molded article characterized by being formed. 2. The plastic molded body according to claim 1, wherein the plastic molded body formed by connecting the two components with a thin hinge part integrally formed with the two components is blow molded. 3. A groove formed in a hinge portion is continuous in a direction orthogonal to a bending direction as a hinge, and has a triangular cross-sectional shape.
Or the plastic molded article according to 2. 4. The plastic molded body according to claim 1, wherein a concave groove is formed on one surface of the hinge portion. 5. The plastic molded body according to claim 1, wherein the hinge portion has concave grooves formed on both surfaces thereof. 6. The plastic molded product according to claim 4, wherein the thickness of the hinge portion is 0.4 to 0.8 mm, and the depth of the concave groove is 0.1 to 0.4 mm. 7. The hinge part has a thickness of 0.45 to 1.0 mm.
The plastic molded body according to claim 5, wherein the depth of the concave groove is 0.1 to 0.4 mm.