JP3003125B2 - Mold device for molding half case for mini disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for forming a half-case for a mini-disc containing an optical disc-shaped record carrier.

[0002]

2. Description of the Related Art Recently, an information storage device for audio called a mini disk (MD) is being put to practical use. As shown in FIG. 4, the mini disc 1 has an optical disc-shaped record carrier 2 housed in a rectangular thin case 3 and has the same structure as a micro floppy disc. The case 3 is formed by connecting an upper case 4 and a lower case 5 as a pair of half cases. The upper case 4 has a recessed shutter assembly 6 formed on one side thereof in a thin-walled shape. The shutter assembly 6 has a window hole 7 opened toward the disk-shaped record carrier 2. A shutter 8 for opening and closing the window hole 7 is slidably incorporated. The shutter 8 is usually provided so as to cover the window hole 7 by an elastic machine (not shown) provided in the case 3. A circular opening 9 is formed in the center of the upper case 4 so that a drive shaft (not shown) for rotating and driving the disk-shaped record carrier 2 is inserted through the opening 9. Has become. The size of the mini-disc 1 is about 70 mm in each of the vertical and horizontal directions, and is relatively small.

When the upper case 4 is molded, injection ports (gates) 10 are provided at positions corresponding to two opposing corners of the surface of the upper case 4, and molten resin is injected into the cavity from the two-point gate 10. Is supplied to form the upper case 4. Therefore, the molten resin injected from the two gates 10 flows toward the center of the upper case 4.

[0004]

When the molding is performed by the two-point gate 10 as in the prior art, two gates are required.
Since the molten resin injected from 10 flows toward the center of the upper case 4, two traces of the gate remain and the appearance is inferior, and the molding of the shutter assembly part 6 and the opening part 9 is defective. Is concerned. Further, the gas release in the central portion is likely to be insufficient, and a slim surface may be formed on the surface of the molded product, or the molded product may be warped because pressure is not uniformly applied in the molded product. .

The present invention is intended to solve such a problem. In addition to improving the aesthetic appearance of the half case by using a single gate, the molten resin flows smoothly in the cavity and gas is released. An object of the present invention is to provide a mold apparatus for molding a half-case for a mini-disc, which can be performed smoothly and can prevent defects such as a wetting surface and warpage from occurring in a molded product.

[0006]

According to the present invention, in order to achieve the above object, a molten resin is supplied to a cavity in a mold to form a shutter-integrated portion having a window hole on one side in a concave shape. In a molding die apparatus for forming a mini-disc half case for accommodating a disc-shaped record carrier by forming an opening separated from the window at the center, a portion which is not covered by a normal shutter in the shutter built-in portion. In addition, an injection port of the molten resin into the cavity is provided on the engraved surface of the mold corresponding to the vicinity of the window and the opening.

[0007]

In the mold apparatus for molding a half-case for a mini-disc of the present invention, molten resin is first supplied to a portion of a cavity corresponding to a thin shutter mounting portion, and further a window hole and an opening of a shutter mounting portion are formed. The molten resin is supplied around the periphery. At that time, since the injection port is located near the window hole and the opening that are separated from each other, the resin injected from the injection port has a portion forming the window hole and a portion forming the opening in the cavity. Is reliably supplied to both sides of the window hole and the opening through the passage formed between them.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view showing a part of a mold apparatus for molding an upper case 11 as a half case for a mini disk as shown in FIGS. Case on this
Numeral 11 is formed in a substantially square thin-walled surface.
On one side of 12, a shutter assembly 14 for mounting a shutter 13 is formed, and on the other side a label (not shown)
A label mounting surface 15 for attaching the shutter mounting portion 14 and the label mounting surface 15 are formed to be slightly concave and thinner than other portions. The thickness of the shutter assembly 14 is smaller than the thickness of the label mounting surface 15. Further, the shutter built-in section 13
Is formed with a window hole 17 opening toward the disc-shaped record carrier 16. The inner surface 18 of the upper case 11
On the side, an outer frame portion 19 is formed over substantially the entire area of the outer edge portion, and an arc-shaped rib portion 20 is formed so as to be continuous with the outer frame portion 19. An inner side of the rib portion 20 is a record carrier accommodating portion 21 for accommodating the disc-shaped record carrier 16. An elastic storage portion 22 for storing an elastic device (not shown) for urging the shutter 13 to always close the window hole 17 is located outside the rib portion 20, and the shutter mounting portion 14 Is formed in the vicinity. Further, a circular opening 23 is formed at the center of the upper case 11. This opening
Reference numeral 23 is separated from the window hole 17.

As shown in FIG. 1, a mold for molding the upper case 11 configured as described above includes a fixed mold plate 24 having an engraved surface 24A for forming the surface 12 of the upper case 11, A movable mold plate 25 having an engraved surface 25A for forming the inner surface 18 of the case 11; and an injection port (gate) for injecting molten resin into a cavity 26 formed between these mold plates 24, 25. ) 27 is provided on the side of the engraving surface 24A, and the injection port 27 is a part which is not covered by the normal shutter in the shutter built-in part 14, that is, a shutter indicated by a dashed line.
13 and the window hole 17 and the opening
2 is provided on the fixed mold plate 24 corresponding to the vicinity of 23, and FIG.
At the gate mark 28. FIG.
2 shows a cross section along the line AA in FIG. 2 of the upper case 11 in the cavity 26, and FIG.
The cross section along the line is shown.

When the upper case 11 is formed by using the mold apparatus configured as described above, the space between the fixed mold plate 24 and the movable mold plate 25 is closed as in the conventional case, and both mold plates 24 are closed. , 25, a molten resin such as polycarbonate is supplied from the injection port 27. At this time, the molten resin supplied from the injection port 27 first flows through a portion of the cavity 26 corresponding to the shutter assembly portion 14 including the window hole 17, and is thereafter supplied to other portions of the cavity 26. In particular, at the portion of the cavity 26 corresponding to the opening 23, the injection port
Since 27 is located in the vicinity, the molten resin is quickly supplied and supplied. Furthermore, since the injection port 27 is located near the window hole 17 and the opening 23 which are separated from each other, the resin is located between the portion forming the window 17 and the portion forming the opening 23 in the cavity 26. It is reliably supplied to both sides of the window 17 and the opening 23 through the formed passage.

As described above, since the molten resin injection port 27 is provided at one location, the gate trace 28 can be provided at one location in the upper case 11, which is a molded product, and the appearance can be improved. Further, since the injection port 27 is provided corresponding to the shutter mounting portion 14, the molten resin can be reliably supplied to the portion of the cavity 26 corresponding to the thin shutter mounting portion 14. In addition, since the inlet 27 is located near the window 17 and the opening 23, the molten resin can be reliably supplied to the cavity 26 corresponding to the periphery of the window 17 and the opening 23. it can. In addition, since the window 17 and the opening 23 are separated from each other, the resin passes through the passage formed between the portion forming the window 17 and the portion forming the opening 23 in the cavity 26. And is reliably supplied to both sides of the opening. In addition, degassing around the opening 23 becomes sufficient, and it is possible to eliminate the risk that a slim surface is formed on the surface of the molded product, or that the molded product is warped due to non-uniform pressure applied within the molded product.

The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, only the upper case 11 of the pair of cases is provided with the shutter mounting portion 14 and the opening 23 so that the disc-shaped record carrier 17 is provided. Although only one surface of the disk-shaped record carrier can be read, various modifications are possible, such as that the upper case may be paired so that both surfaces of the disk-shaped record carrier can be read.

[0013]

According to the present invention, a portion which is not covered by a normal shutter in a shutter built-in portion having a window hole, and is melted corresponding to the vicinity of the window hole and an opening separated from the window hole. By providing the injection port of the resin into the cavity on the engraved surface of the mold, the appearance of the half case can be improved with one gate mark, and further, the shutter built-in part, the window hole, and the cavity corresponding to the opening part can be improved. Molten resin flows smoothly into the area of the window, and in particular, the resin surely flows to both sides of the window hole and the opening through the passage formed between the part forming the window and the part forming the opening in the cavity. It is possible to smoothly supply and degas the gas, and to prevent the molded product from having defects such as a wetting surface and warpage.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mold showing one embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention as viewed from the front side of an upper case.

FIG. 3 is a plan view showing an embodiment of the present invention as viewed from an inner surface side of an upper case.

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

[Explanation of symbols]

 14 Shutter assembly part 17 Window hole 23 Opening 24 Fixed mold plate (Mold) 25 Movable mold plate (Mold) 25A Engraved surface 26 Cavity 27 Inlet

Claims (1)

(57) [Claims] 1. A molten resin is supplied to a cavity in a mold to form a shutter installation portion having a window hole in a concave shape on one side, and an opening portion separated from the window hole is formed in the center. In a molding die apparatus for molding a half-case for a mini-disc containing a shape-recording carrier, a part that is not covered by a normal shutter in the shutter built-in part and corresponds to the vicinity of the window and the opening. A mold device for molding a half case for a mini-disc, wherein an injection port of a molten resin into a cavity is provided on an engraved surface of the mold.