JPH0423621B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to attachment cases, camera cases, musical instrument cases, etc., which are constructed by closing the opening edges of a pair of halves, such as a main body and a lid, so that they can be opened and closed. , a method of manufacturing plastic cases such as word processor cases and tool cases.

[Conventional technology]

BACKGROUND ART It has been known to manufacture the halves of attachment cases using thermoplastic plates such as ABS resin and by plate forming such as vacuum forming and pressure forming. Then, the opening edge of the half of the attachment case obtained by the manufacturing method described above is covered with a separate cap, and the base end of the cap is attached to the outer wall of the opening edge with screws to increase the strength of the opening edge. It is also known to improve (Japanese Unexamined Patent Publication No. 48-12179) Although the basic structure is different from the plastic case of the present invention, which is constructed by opening and closing the opening edges of a pair of halves such as a main body and a lid body, In a plastic container that can be stored in a container that can be put in and taken out freely, a frame-shaped reinforcing frame is installed along the opening periphery of a female-shaped recess formed with a predetermined shape for the purpose of reinforcing the opening edge of the container. A plastic sheet is supported so as to protrude into the opening of the recess, a plastic sheet is made to correspond to the female mold by covering the opening of the recess so as to cover the reinforcing frame, and the plastic sheet is attached to the reinforcing frame using a vacuum forming method. A method of manufacturing a plastic container is known, in which the reinforcing frame is largely covered and retained by the plastic sheet, by being deformed through the space enclosed by the plastic sheet to form a shape that matches the recess. (Japanese Patent Publication No. 58-37887) [Problems to be solved by the invention] As shown in JP-A-48-12179,
A plastic case such as an attachment case, in which the opening edges of a pair of halves, such as the main body and the lid, are covered with separate caps and attached with screws, is useful in terms of improving the strength of the opening, but each The work of attaching the base with screws to each half of the body is complicated,
In addition, the screw portion was exposed on the inner and outer walls, resulting in a poor aesthetic appearance.

Furthermore, even if you try to use so-called insert molding as shown in Japanese Patent Publication No. 58-37887, the separate reinforcing frame will be covered with the molded plastic sheet, and if you try to obtain a plastic case. The abutment surfaces of the opening edges of the pair of halves that can be freely opened and closed are located on the sides that do not contact the mold of the plastic sheet being molded, so the abutment surfaces cannot be accurately closed, and the main body It is unsuitable as a means for reinforcing the opening edges of a pair of halves, such as a lid and a lid, in terms of the consistency of the mating surfaces.

[Means for solving problems]

The present invention solves the above problems,
An object of the present invention is to provide an attachment case which has excellent consistency between the mating surfaces of a pair of halves such as a main body and a lid, which can reinforce the strength of the opening edges of the halves, and which has an excellent appearance. It is an object of the present invention to provide a manufacturing method that makes it possible to easily obtain such a plastic case.

That is, the present invention opens a split-type mold consisting of a half mold having a concave cavity formed on the inner surface, and a half mold having a convex cavity extending from the mating surface of the half mold into the concave cavity formed on the inner surface. The mating surface member of the case is temporarily fixed so as to surround the proximal end of the convex cavity, a parison made of thermoplastic plastic is placed between the split molds, the mold is closed, and the inside of the parison is The present invention relates to a method of manufacturing a plastic case, which involves blowing pressurized fluid into the plastic case to expand the parison, welding the parison to a mating surface member of the case, and molding the parison along the shape of the cavity.

[Effect]

In the process of manufacturing a plastic case that is constructed by closing the opening edges of a pair of halves, such as the main body and the lid, in an openable and closable manner, when the cases are closed together, the mating part located at the tip of the opening edge of the case that comes into contact with Since the surface member is temporarily fixed to the proximal end of the convex cavity, it is accurately placed within the mold. Further, the mating surface member is welded integrally with the parison in the mold, and the plastic half to be molded and the mating surface member are firmly joined.

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

In FIG. 1, 1 is a plastic case manufactured by the manufacturing method of the present invention, and the case 1 is composed of a hollow double-walled main body 2 and a lid 3, and 2a and 3a are inner walls, respectively. 2b and 3b are respective outer walls. The main body 2 and the lid 3 are connected so as to be openable and closable by a hinge 4 formed by compression thinning, and the main body 2, the lid 3 and the hinge 4 are made of a single plastic material, such as polyethylene,
It is constructed by integrally blow molding thermoplastic plastics such as polypropylene, polyamide, ABS resin, etc. as described below. 5 and 6 are case mating surface members welded to the opening edges of the main body 2 and lid body 3 during blow molding, and the case mating surface members 5 and 6 have a stepped portion 8 formed on their mating surfaces 7 to close the case. Case mating surface members 5 and 6 when mating
are configured to mate. Further, 9 is a handle of the case attached to the case mating surface member 5, and 10 is a storage part of the case.

The case mating surface members 5 and 6 are preferably made of aluminum, which is more rigid and has superior mechanical strength than the main body 2 and the lid 3, or a hard plastic material.

Hereinafter, the manufacturing method according to the present invention will be explained based on FIGS. 2 and 3.

In the figure, numerals 11 and 12 are a pair of halves constituting a split-type mold, and numeral 13 is a parison that is extruded into a cylindrical shape from an extrusion head 14. Above half mold 11
The inner wall 2 of the main body 2 and lid body 3 to be manufactured is
Convex cavities 15a, 16 for forming a, 3a
A compression portion 17a is formed between the convex cavities 15a and 16a to clamp the parison 13.

Further, temporary fixing parts 18 and 19 for temporarily fixing the case mating surface members 5 and 6 are formed in the shape of a groove so as to surround the entire circumference of the proximal ends of the convex cavities 15a and 16a. On the inner surface of the other half mold 12 are concave cavities 15b, 16b for forming the outer walls 2b, 3b of the main body 2 and the lid 3, and the concave cavities 15b,
Compression part 17 that compresses parison 13 between 16b
b is formed. When the mold is closed, the convex cavities 15a and 16a are configured to extend into the concave cavities 15b and 16b from the mold mating surface 20 of the other half mold 12, respectively.

In the present invention, when manufacturing the plastic case 1, first, as shown in FIG. The mating face members 5 and 6 of the separate pre-formed case are temporarily fixed to the groove-shaped temporary fixing parts 18 and 19, and the half mold 1 is assembled.
A cylindrical parison 13 made of thermoplastic plastic is inserted between extrusion head 1 and 12.
4. Extrude and arrange. Next, Parison 13
The concave cavities 15b, 16 are closed by closing the lower ends with the pinch member 21, and pre-blowing by blowing fluid from the mandrel of the extrusion head 14, etc.
The parison 13 is pre-inflated and inserted into the interior of the mold half 1 up to the vicinity of the case mating face members 5 and 6 which are temporarily fixed to the proximal ends of the convex cavities 15a and 16a.
1 and 12 are closed. Next, as shown in FIG. 3, the blowing nozzle 22 is pierced into the parison 13, and pressurized fluid is blown into the parison 13 from the blowing nozzle 22 to expand the parison 13, thereby forming the convex cavity 15a and the concave cavity 15b. The main body 2 with a hollow double wall structure is formed in the space surrounded by the hollow double wall structure, and the lid body 3 with a hollow double wall structure is formed in the space surrounded by the convex cavity 16a and the concave cavity 16b.At the same time, the case mating surface is formed. The members 5 and 6 are welded together with the expanded parison 13 by the melting heat of the parison 13. In addition, half molds 11 and 12
By closing the middle parison 13, the compression parts 17a and 17b compress and compress the hinge 4, which is compressed and thinned. Then, after cooling, half mold 1
1 and 12 are opened, excess burrs on the molded product are removed, and a handle 9 is attached to obtain a plastic case 1 as shown in FIG.

The main body 2 and lid 3, which are molded from the parison 13 as shown in FIGS. 2 and 3, shrink when cooled after molding. Therefore, when the case mating surface members 5 and 6 are temporarily fixed to the inner surface of the half mold 11, they are preheated in advance according to the coefficient of thermal expansion of the material of the case mating surface members 5 and 6 themselves, and the shrinkage difference after molding is adjusted. It is preferable to prevent the plastic case 1 from being deformed. In addition, as shown in Fig. 4, half mold 1
Convex cavity 15 formed on the inner surface of 1 and 12
a, 16a and the portion 23' forming the opening edge of the concave cavities 15b, 16b are molded to be slightly curved outward as shown by solid lines, and the plastic case 1 is shaped into the desired rectangular shape by shrinkage after molding. The opening edge 23 may also be configured.

Furthermore, the method for manufacturing a plastic case according to the present invention is suitable for obtaining a plastic case with excellent airtightness because the mating surfaces of the cases are excellent in consistency, and as shown in FIG. A concave groove 35b is formed on the outer surface of the case mating surface member 35 made of a hard material such as polypropylene, which is embedded in the main body 32 by a bulge 35a, and a groove 35b is embedded in the lid 33 by a bulge 36a. A projecting strip 36b is formed at the tip of the case mating surface member 36 made of an elastic material such as rubber, and when the case is closed,
By pressing the groove 35b and the protruding strip 36b and slightly deforming the protruding strip 36b, a plastic case with excellent sealing performance can be obtained.

Further, in the above embodiment, the hinge 4 is integrally formed with the main body 2 and the lid 3 using the same material, but the present invention is not limited to the above embodiment. The main body 2 and the lid 3 can be molded separately from the lid 3.

FIG. 6 shows another embodiment of a plastic case manufactured by the manufacturing method of the present invention, in which a bearing portion 45 constituting a hinge is provided at the opening edge of the main body 42.
A and a shaft 45b are integrated into a case mating surface portion 45 that is welded together when the main body 42 is molded.
A bearing portion 4 constituting a hinge is provided at the opening edge of the lid body 43.
6a and the shaft 46b are integrally welded together when the lid body 43 is molded, and the bearing portion 45a and the shaft 46b as well as the bearing portion 46a are integrally welded together.
By engaging the shaft 45b and the shaft 45b, a plastic case that can be opened and closed can be obtained. In addition, as shown in FIG. 6, the case mating surface member 45
and 46 have the same shape, the case mating surface member of the main body 42 and the lid body 43 can be shared by one type of case mating surface member, and a plastic case can be obtained without using a separate hinge member. be able to.

〔Effect of the invention〕

According to the present invention, there is provided an attachment case that has excellent consistency between the mating surfaces of integral halves such as the lid of the main body, can reinforce the strength of the opening edges of the halves, and has an excellent appearance. You can easily get a plastic case like this.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway side view of a plastic case manufactured by the manufacturing method of the present invention, Figs. 2 and 3 are schematic cross-sectional views of a mold showing the manufacturing process of the present invention, and Fig. 4 is a mold. FIGS. 5 and 6 are side sectional views of main parts showing other embodiments of the plastic case manufactured by the manufacturing method of the present invention. and an exploded perspective view. 1: Plastic case, 2: Main body, 3: Lid, 5, 6: Case mating surface member, 11, 12:
Half mold, 15a, 16a: convex cavity, 15
b, 16b: concave cavity.

Claims (1)

[Claims] 1 Open and arrange a split-type mold consisting of a half mold with a concave cavity formed on the inner surface and a half mold with a convex cavity formed on the inner surface from the mold mating surface of the half mold and a convex cavity formed on the inner surface, The mating surface members of the case are temporarily attached so as to surround the base end of the shaped cavity, a parison made of thermoplastic plastic is placed between the split molds, the mold is then closed, and pressurized fluid is introduced into the parison. A method for manufacturing a plastic case, which comprises expanding a blown parison, welding the parison to a mating surface member of the case, and molding the parison along the shape of a cavity.