JPS585229A - Manufacture of plastic case - Google Patents

Abstract

PURPOSE:To produce a case having hinges with suitable rigidity, by blow molding a hinge which is integrally connecting a main body and a lid body, and cutting out part of the hinge to form a plurality of hinges. CONSTITUTION:A pressurized fluid such as pressurized air is blown via a blowing needle 8 into a parison 6 so that the parison 6 in mold 7 is blown into the main body 2 and the lid body 3, having a hollow double structure. In this case, after cooling, the mold 7 is opened, the molded plastic case is taken out, and part of the hinge 4 is cut out to form hinges 4a, 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a plastic case with good hinge properties.

Previously, special public show Q9-/&? As shown in the QG publication, it consists of a main body, a lid, and a hinge that connects them, and the hinge is specially compressed and formed thinly, and the main body,
A blow-molded plastic case in which at least one of the lids has a hollow double-wall structure is used as a multipurpose case because of its excellent cushioning properties.

However, small plastic cases have a disadvantage in that the hinges are so rigid that even if the lid is closed, unless it is locked, the lid will open automatically, making it very inconvenient to use. In addition, the rigidity of the hinge of thin-walled plastic cases is too strong, and when the lid is closed, the main body and lid around the plastic hinge are deformed, reducing the product value.

The present invention overcomes the above-mentioned drawbacks and provides a method for manufacturing a plastic case with good hinge properties.

An embodiment of the present invention will be described below with reference to the drawings, and the manufacturing method according to the present invention is based on the technical content disclosed in Japanese Patent Publication No. 4/99-7g7q.

FIG. 1 shows a plastic case manufactured by the manufacturing method of the present invention, where the case is a main body, a lid 3, and a main body 2. It consists of a hinge q that connects the lid 3, and is integrally formed by a blow molding method that will be described later. The main body and the lid 3 each have a hollow double-walled structure, and the 2 person/3A storage section is formed into an arbitrary shape. During blow molding, the hinge q is compressed in a compression section within the mold cavity and is formed into a thin wall. In addition, the hinge q is partially removed after molding to form a plurality of hinges IIa.
-1 lb.

Next, to explain the method for manufacturing the plastic case according to the present invention, in FIG. 2, thermoplastic plastics such as polyethylene and polypropylene are melt-kneaded in an extruder (not shown), Extrude as parison 6. Next, after closing the split-type mold 7, pressurized fluid such as compressed air is blown into the burr thread 6 through the blowing needle g, and the parison 6 in the mold 7 is blown, thereby creating a hollow double-walled structure. The main body and the lid 3 are formed. At this time, the parison 6 is held and compressed by the compression part of the mold 7, thereby forming a thin hinge. After cooling, the mold 7 is opened, the molded plastic case is taken out, and excess paris is removed. Next, as shown in FIG. 3, the hinges are partially removed by punching or cutting to form a plurality of hinges fa and llb. Further, it is preferable in terms of hinge characteristics that the length L of one hinge IIa is formed to be 7 to 5 times, more preferably 7 to 3 times, the width W of the hinge. That is, the length L
If it is less than 7 times the width W, the hinge is likely to crack when used as a plastic case and cannot withstand long-term bending. In addition, if the length L is more than 5 times the width W, the rigidity of the hinge will be too strong, and even if the lid is closed, it will open automatically unless it is locked, and the main body and lid near the hinge will be deformed. , the purpose of the present invention cannot be achieved. At this time, the number of hinges is not limited to two, but can be formed to any desired number, and the shape is not limited at all.

It is also possible to integrally form the handle, latch, etc. during the blow molding shown in FIG.

As described above, the present invention involves integrally molding the main body, the lid, and the hinge connecting them by blow molding, and then partially removing the hinge to form a plurality of hinges, thereby increasing the rigidity of the entire hinge. The present invention relates to a method for manufacturing a plastic case, which is characterized in that the case has good hinge characteristics, and the hinge is so rigid that the lid may open naturally or the lid may There is no fear that the main body or lid near the hinge will deform when closed.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a plastic case obtained by the manufacturing method of the present invention, Figure 2 is a schematic diagram of a mold showing the blow molding process, and Figure 3 is a plastic case showing the state before the hinge is partially removed. FIG. 3 is a top view of main parts of the case. /: Blasti, Case 2 = Body 3: Lid I: Hinge Patent Applicant's Drawings Figure 1 A Figure 2 ゛ Figure 3 Procedures Amendment Written by Kazuo Wakasugi, Commissioner of the Japan Patent Office, July 76, 1939 Indication of the Tono l case Patent application 3 filed on June 77, 1960, relationship with the amended case Patent applicant 7, Ryumae-cho sqg, Karasuma-dori, Kamigyo-ku, Kyoto-shi, Kyoto Prefecture jDate of amendment order Application subject to spontaneous 5 amendments and details of the amendment As attached (no change in content)

Claims (1)

[Claims] A plastic case characterized in that a main body, a lid, and a hinge connecting them are integrally molded by blow molding, and then the hinge is partially removed to form a plurality of hinges, and the rigidity of the entire hinge is adjusted. manufacturing method.