JPS60179237A - Manufacture of container made of synthetic resin in thin surfacelike state - Google Patents

Abstract

PURPOSE:To obtain a container to be used for a floppy disc which is superior in shape retention, strong, thin, favorable in accuracy and light in weight, by joining unitarily half cases molded by injection molding by two kinds of molds to be obtained by arranging gates on almost the central part of a molding cavity with each other. CONSTITUTION:A cavity 26 is formed by combining a stationary side engraved part 23a and a movable side engraved part 24a with each other. As for the cavity 26, hereupon, two kinds of cavities whose shapes are different from each other are prepared for molding two kinds of half cases A, B. Then molten resin is poured into the cavity 26 through a gate 39 arranged on the centeral part of the cavity 26, and when the resin is cooled and solidified, a movable side template 24 is moved and a mold is broken. As for the half cases A, B molded like this, after they have contained a floppy disc, protrusions 1, 2, 4, 12, 14 are fitted in protrusions 11, 10, 13, 5, 3, which are jointed with each other through adhesion, welding and fusing and a product is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a 70-tube disc, a compact disc,
Alternatively, the present invention relates to a method of manufacturing a thin-walled synthetic resin container for accommodating video discs and the like.

In general, containers for storing 1-frame, 4-piece disks, etc. are thin, not bulky, strong, have a high protection function for the stored items, have good accuracy, do not warp or bend, and have good shape retention. ,
In addition, it is desired that the container be lightweight, so in the past, paper containers were usually used as containers for floppy disks, but there were complaints that they were weak in strength and lacked protection. For this reason, a thin-walled container made of synthetic resin has been proposed in which two half cases are molded by injection molding of synthetic resin and these half cases are joined together. This may cause deformation and deformation, which is not desirable for use as a container for high-precision floppy disks, etc.

The proponent of the present invention believes that the causes of the above-mentioned warping and bending are due to various conditions such as temperature, pressure, etc. when synthetic resin is injected into the molding cavity through multiple gates drilled in each part of the molding cavity. It was discovered that there is a slight change in each gate, which causes internal stress when the molten resin solidifies, and the present invention was made based on this new knowledge.

That is, the present invention involves injection molding two half cases using two types of molds in which a busy gate is provided approximately in the center of the molding cavity, and integrally joining the two half cases. Provides a method for manufacturing thin-walled synthetic resin containers that are free from warping or bending, have excellent shape retention, are strong, thin, have good precision, and are lightweight. The purpose is to

The present invention will be specifically explained below with reference to the drawings. Figures 1 to 5 show an example of a half case of a floppy disk manufactured by the method of the present invention. A, I3 are two approximately rectangular half cases. At the four corners of the inner surface of the half case, ring-shaped projections 1, 2, 3.4 and two parallel linear projections 5 are formed, and at the center of the inner surface,
A gate mark 6 is formed. Also, two ring-shaped protrusions 7 and 8 are formed concentrically around this gate mark 6.
A rectangular hole 9 for data writing and reading is provided. Furthermore, each of the four inner corners of half case B,
Ring-shaped protrusions 10, 11, 12, 13, and 14 are formed, and in FIGS. 4 and 5, circular holes and rectangular holes for data writing and reading are formed at the center and lower center of the inner surface, respectively. 15°16 are drilled. Then, a donut-shaped floppy disk (not shown) is stored in the half cases A and R, centering on the gate mark 6, and the protrusions 1, 2, 4, 12.
After fitting into the case 0, 13, 5.3, the two types of half cases A and B are joined by adhesion, welding, fusion, etc.

1 Regarding the molding equipment for injection molding the two types of half cases A and B configured as described above using a hot runner.
．． This will be explained with reference to FIG.

20 in the figure is a fixed side mounting plate, and this fixed side mounting plate 2
0 to the bank plate 2 via the spacer block 21.
2 is installed. This back plate 22 has
A fixed side template 23 having a fixed side engraving portion 23 & is attached. Further, 24 is a movable side template having a movable side engraving portion 24a, and this movable side template 24 is attached to a movable side mounting plate 25. Then, the mating surface between the fixed side template 23 and the movable side template 24 is a parting plane (parting line) PL, and the fixed side engraving part 23IL and the movable side engraving part 24a are combined to form the no-fuss case A.
Alternatively, a cavity 26 for half case B is formed.

A locate ring 27 is attached to the fixed side mounting plate 20, and a manifold 29 is fixed via a sprue bush 28. This manifold 29 is supported by the back plate 22 via a support member 30, and is connected to the fixed side template 23 from the manifold 29.
A cylindrical runner bush 31 is provided throughout. And the above sprue bush 28, manifold 29
A molten resin flow path 32 is formed passing through the inside of the runner bush 31 and the fixed side mounting plate 23a of the fixed side mold plate 23, respectively. 33
is inserted.

Furthermore, between the stepped portion 21a of the spacer block 21 and the back plate 22, there are two ejector plates.
34.3B are provided movably, and the ejector pins 36 whose base ends are attached to these ejector plates 34.35 are connected to the back plate 22 and the fixed side template 2.
It is provided so as to penetrate through the fixed side engraving portion 23a of No. 3.

Furthermore, the ejector return pin 37 whose base end is attached to the ejector plate 34, 35 is attached to the back plate 2.
2 and fixed side mold plate 23, and around this ejector return pin 37, an ejector plate 34, 35 is attached to the stepped part 2 of the spacer block 21.
A spring 38 is attached to push it back toward 1a.

Note that the gate 3 for injecting molten resin into the cavity 26 of the half case A or the half case B formed by the fixed side engraving part 23& and the movable side engraving part 24a
9 is installed at a position corresponding to the center of the inner surface of half case A or near the periphery of hole 1'5 on the inner surface of half case B. Further, a plurality of gates 39 for injecting molten resin into the cavities 26 for the half cases A and B may be provided in the central portion of the cavities 26.

Next, synthetic resin is produced using the molding equipment configured as described above. J! ! A method for manufacturing a thin-walled container will be explained.

First, tighten the mold, and
A and the movable-side engraving portion 24a of the movable-side template 24 are combined to form a cavity 26. Here, this cavity 26
is the above two types of A-7. In order to mold cases A and B, two types of cases with different shapes are prepared. Next, when the molten resin is injected from an injection molding machine (not shown), the molten resin passes through the sprue bush 28, passes through the manifold 29 for keeping the resin in a molten state, and the hot tip 33, and is placed in the center of the cavity 26. It is injected into the cavity 26 through the gate 39 that has been opened. When the injected resin is cooled and solidified, as shown in FIG. 6, the movable mold plate 24 moves to the left to open the mold, and the ejector plates 34 and 35 move to the left. Therefore, half case A or half case B, which has been pressure molded inside cavity 26, is ejected by ejector bin 36 and taken out. The ejector bin 36 is returned by the force of a spring 38 inserted into the ejector return bin 37.

Half case A was formed in this way.

B stores a donut-shaped 70-tupee disk inside, and then combines each half case A and B to form protrusion 1,
2. Insert 4.12.14 into projection 11.10°13.5.3. The two types of half cases A and B are then joined together using adhesive, welding, fusion, etc. buttons to complete the product.

In addition, when molding the above half cases A and B,
The molding device shown in FIG. 7 may be used, and this molding device has ejector plates 42 and 43 movably left and right in the space formed by the fixed side mounting plate 20, the spacer block 40, and the support plate 41. A manifold 45 is provided in the space formed by the support plate 41, the spacer block 44, and the back plate 22. After closing the mold (after forming a cavity by combining the fixed side engraving part 23a of the fixed side template 23 and the movable side engraving part 24a'i of the movable side template 24), the molten resin fills the inside of the sprue bush 46. It passes through the inside of the manifold 45 and the outer periphery of the hot tip 47, and is injected into the cavity from the gate 48 disposed in the center of the cavity.

When the resin cools and solidifies in the cavity, the mold is opened and the ejector plates 42, 43 move to the left, causing the ejector pins 49 to eject the molded product (half case A or B).

As explained above, one aspect of the present invention is to injection mold two half cases using two types of molds in which a gate is arranged approximately in the center of the molding cavity, and to mutually attach the two half cases to each other. Since it is made by joining together to produce a thin-walled container made of synthetic resin, it has excellent shape retention without warping or bending, is strong, thin, has good precision, and is lightweight. You can make containers. Therefore, it has an excellent effect in that the quality of the plate-like object such as a floppy disk housed inside can be maintained well for a long period of time.

[Brief explanation of the drawing]

FIGS. 1 to 5 show a half-piece manufactured according to the present invention.
Fig. 1 is a perspective view, Fig. 2 is a diagram showing the inside of half case A, and Fig. 3 is a diagram showing the inside of half case A.
-A cross-sectional view taken along the N line, Figure 4 is a view showing the inside of half case B, Figure 5 is a cross-sectional view taken along the v-v line in Figure 4, and Figure 6 is the molding process for forming the half case. FIG. 7 is a sectional view showing another embodiment of the molding apparatus for molding a half case. A, B... Half case, 26... Cavity, 39... Gate, 48... Gate. Figure 1 Shin 2 Figure 3M Figure 6

Claims (1)

[Claims] Using two types of molds each having a gate approximately in the center of the molding cavity, and injecting synthetic resin into the molding cavity of the mold through the gate, two different half cases were injection molded. A method for manufacturing a thin-walled synthetic resin container, comprising manufacturing a synthetic resin thin-walled container by integrally joining 7-7 cases.