JPH0722944B2 - Mold device for molding disk case - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a molding die for molding a disk case for accommodating a disk-shaped storage disk body such as a magnetic disk, an optical disk, or an optical-magnetic disk. Regarding the device.

[Conventional technology]

Conventionally, when molding this kind of disc case, gates (injection ports) are provided at positions corresponding to the four corners of the surface of the disc case, and molten resin is supplied from the four-point gate into the cavity to form the disc case. Since the case is molded, the molten resin injected from the four gates flows toward the central portion of the disk case.

[Problems to be Solved by the Invention]

By the way, in the case of molding by the four-point gate as described above, especially in the upper case where there is no through hole in the central portion,
There is a problem that the degassing in the central portion is likely to be insufficient, a wet surface is formed on the surface of the molded product, or the molded product is warped because pressure is not uniformly applied to the molded product.

Therefore, as a solution to the above problem, an injection molding gate mark is provided only near one side end of the drawing plate part, and the side end part on the side opposite to the gate mark is the resin filling end position, and A disk cartridge has been proposed in which a resistance portion which is a resistance against the flow of resin at the time of molding the case is provided at the side end opposite to the gate trace (Japanese Patent Laid-Open No. 1-21).
See 7780).

However, in the above-mentioned conventional disc cartridge, since the resistance portion is provided at the side end portion on the side opposite to the gate trace, the flow of resin during molding is obstructed, which adversely affects the molding of the disc cartridge. There is a problem.

The present invention has been made in view of the above circumstances, and an object thereof is to allow a resin to smoothly flow in a cavity and to smoothly perform degassing, and to allow a molded product to have a wet surface, a warp, and the like. It is an object of the present invention to provide a mold device for molding a disk case, which can prevent the above problems from occurring.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a molding die apparatus for forming a disk case for storing a disk-shaped storage disk body by supplying the molten resin to a cavity in the mold, The injection port to the cavity of the cavity is arranged at two points on the engraved surface of the mold which is a portion which is normally covered with the shutter and which corresponds to the outside of the storage portion of the storage disk body. A degassing portion is formed in the central portion, and the thickness of the portion of the cavity corresponding to the outside of the storage portion of the storage disk body is set to be larger than the thickness of the portion corresponding to the storage portion of the storage disk body. It was done.

[Action]

In the mold device for molding the disc case of the present invention,
The molten resin supplied into the cavity from two injection ports (gates) that are normally hidden by the shutter and that are located at two points on the engraving surface of the mold that corresponds to the outside of the storage portion of the storage disk body is used for storage. The portion corresponding to the outside of the storage portion of the storage disk body, which is set to be thicker than the thickness of the portion corresponding to the storage portion of the disk body, flows more smoothly, and is formed in the central portion of the cavity far from the inlet. Reaching the degassing portion, the filling of the resin into the entire space inside the cavity is completed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view showing a part of a mold device for molding an upper case 1 for a floppy disk as shown in FIGS. 2 and 3. The upper case 1 is formed in a substantially square thin-walled surface, and a surface 1a has a shutter area 1b for mounting the shutter 6 and a label area 1c for sticking a label. Each is formed to be slightly depressed from the other portions. Further, the upper case 1 is formed with a window portion 1d for introducing a magnetic head and a hole portion 1e for a light protector, respectively. further,
On the inner surface 1f side of the upper case 1, an outer frame portion 1g is formed over substantially the entire outer edge portion thereof, and an arc-shaped rib portion 1h is formed so as to be continuous with the outer frame portion 1g. The inner side of the rib portion 1h serves as a disc body storage portion 1i for storing a disc-shaped storage disc body, and the outer side of the rib portion 1h is the upper right portion of FIG. A spring storing portion 1j for storing a spring for urging the shutter 6 to the right. Furthermore, the thickness of the face plate portion outside the disc body storage portion 1i is set to be larger than the thickness of the disc body storage portion 1i. In particular, in FIG. 3, the thickness of the face plate portions at the lower left corner and the lower right corner is set to be larger than the thickness of the disc body storage portion 1i.

The mold for molding the upper case 1 configured as described above is
As shown in FIG. 1, a fixed template 2 having an engraved surface for forming the surface 1a of the upper case 1, and an inner surface 1f of the upper case 1.
And a movable mold plate 3 having an engraved surface for forming a mold, and an injection port (gate) 5 for injecting a molten resin into a cavity 4 formed between these mold plates 2 and 3 is shown in FIG. As shown in FIG. 3, the shutter area 1b of the upper case 1 is covered with the shutter 6 urged by the spring (shown as a gate mark 1k in FIG. 2) and shown in FIG. As shown in FIG. 3, outside the disc housing 1i of the upper case 1 and as close as possible to the center 7 of the upper case 1 and at a position symmetrical with respect to the center line 1 (in FIG. Is formed on the engraved surface of the corresponding fixed mold plate 2 (represented as a convex portion 1). Further, a plurality of gas venting inserts 8 are attached to the movable mold plate 3, and the gas venting inserts 8 sandwich a center 7 and are opposite to the window 1d as shown in FIG. It is located at the position corresponding to the side. In addition, in FIG.
The upper case 1 in the cavity 4 is shown by I-I in FIG.
A cross section along the line is shown, and in FIG. 3, a cross section along the line I'-I 'is shown.

When the upper case 1 for a floppy disk is molded using the mold apparatus configured as described above, the fixed mold plate 2 and the movable mold plate 3 are closed as in the conventional case, and both mold plates are closed. 2,
Molten resin is supplied from a pair of injection ports 5 into the cavity 4 formed by 3. At this time, two injection ports 5 are arranged at positions symmetrical with respect to the center line l, and the upper case 1
It is formed at a position covered by the shutter 6 in the shutter area portion 1b outside the disc body storage portion 1i at a position corresponding to the center 7 of the case 1 as much as possible, and
The thickness of the portion of the cavity 4 corresponding to the face plate portion on the outer side of the disc body containing portion 1i is set to be larger than the thickness of the portion corresponding to the disc body containing portion 1i, and the central portion on the side far from the inlet 5 is set. Since the degassing insert 8 is attached to the movable mold plate 3, the resin injected from the injection port 5 into the cavity 4 flows from one end side to the other end side (gas removing insert 8 side) and is thick. The thin portion (disc body storing portion 1i) is filled from the meat portion (outer side of the disc body storing portion 1i) and finally reaches the degassing insert 8. As a result, the molten resin is sufficiently supplied to the thin portion, the flow of the molten resin is smoothly adjusted, and the resin is surely spread to each portion, and degassing is easily performed. Therefore, a product of good quality can be obtained without causing defects such as a wetting surface and warpage in the molded product.

Although the molding of the upper case 1 has been described in the above embodiment, as shown in FIGS.
The same can be applied to the molding of.

〔The invention's effect〕

As described above, the present invention relates to a molding die device for forming a disk case for storing a disk-shaped storage disk body by supplying the molten resin to the cavity in the mold, wherein the cavity of the molten resin is Two inlets are provided on the engraved surface of the mold corresponding to the outside of the storage portion of the storage disk body, which is usually covered by the shutter, and the central portion of the cavity on the side far from the inlet. A gas vent is formed in the cavity, and the thickness of the portion of the cavity corresponding to the outside of the storage portion of the storage disk body is set larger than the thickness of the portion of the cavity corresponding to the storage portion of the storage disk body. Therefore, from the injection port (gate), which is normally arranged to be covered by the shutter and which is arranged at two points on the engraving surface of the mold corresponding to the outside of the storage portion of the storage disk body, the inside of the cavity The molten resin supplied to the storage medium smoothly flows through the portion corresponding to the outside of the storage portion of the storage disk body, which is set to have a thickness larger than the thickness of the portion corresponding to the storage portion of the storage disk body, and By reaching the degassing part formed in the central part on the side far from the inlet and completing the filling of the resin into the entire space in the cavity,
It is possible to surely fill the resin in each part in the cavity and to smoothly perform degassing, and it is possible to prevent defects such as a wetting surface and warpage in the molded product.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 and FIG.
The figure shows an example of an upper case molded by using the mold device of the present invention. Fig. 2 is a plan view seen from the surface side of the upper case, Fig. 3 is a bottom view seen from the inner surface side of the upper case, 4 and 5 show an example of a lower case molded by using the mold apparatus of the present invention. FIG. 4 is a plan view of the lower case seen from the front side, and FIG. 5 is an inner surface of the lower case. It is a bottom view seen from the side. 1 ... Upper case for floppy disk, 2 ... Fixed mold plate, 3 ... Movable mold plate, 4 ... Cavity, 5 ... Filling port (gate), 8 ... Gas venting inlet (gas venting part), 9 ...
… Lower case, 1i …… Disk body storage.

Claims (1)

[Claims] 1. A molding die apparatus for forming a disk case for accommodating a disk-shaped storage disk body by supplying molten resin to a cavity in the mold, wherein an injection port of the molten resin into the cavity is provided. Normally, two points are arranged on the engraving surface of the mold which is a portion covered by the shutter and outside the storage portion of the storage disk body, and a gas vent portion is provided in the central portion of the cavity far from the injection port. And the thickness of the portion of the cavity corresponding to the outside of the storage portion of the storage disk body is set larger than the thickness of the portion of the cavity corresponding to the storage portion of the storage disk body. Mold device for molding disk case.