JPH0577876A - Case body for recording medium housing container - Google Patents

Abstract

PURPOSE:To obtain a case body for recording medium housing container which is prominent in design, good in molding with stress concentration reduced, and difficult to break if dropped down, and further in which a gate trace is made to be unremarkable by forming the gate trace on the surface of an upper plate part and at a position corresponding to a center of a hub hole of the recording medium housing container. CONSTITUTION:After a first case body 5 and a second case body 9 are coupled, a cassette is housed in the couple. In this instance, a gate trace 20 of the first case body 5 is positioned in the central part of a hub hole of the cassette. Therefore, when viewed from outward, the gate trace 20 looks doubled with a hub rotation preventing nail which is formed in a bottom plate part 6 of the second case body 9. Accordingly, the gate trace 20 is not remarkable. Further, a circular border line 21 of the first case body 5 coincides with an inner diameter of the hub hole of the cassette. Thus, when viewed from outward, the border line 21 looks doubled with the hub hole, so that it is not remarkable. Thus, design is much improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium container case for accommodating a recording medium container such as an audio tape (recording medium) cassette.

[0002]

2. Description of the Related Art Conventionally, as a cassette case for accommodating an audio tape cassette, as shown in FIG. A transparent resin first case body 5 in which a plate portion 3 is provided, and a rear side of a space formed by the lower plate portion 1, both side plate portions 2 and the upper plate portion 3 is covered by a rear plate portion 4; The side plate portion 7 and the front plate portion 8 are provided on both sides and the front side of the bottom plate portion 6.
It is known that a second case body 9 made of a transparent resin, which is provided with, is openably and closably connected to each other. The opening / closing mechanism of the first and second case bodies 5 and 9 has the second case body 9 in the concave portion (or convex portion) formed near the rear plate portion 4 of the side plate portion 2 of the first case body 5. It is configured by fitting a convex portion (or a concave portion) formed on the inner surface of the side plate portion 7.

[0003]

By the way, in the case of integrally molding the first case body 5 by an injection molding method, conventionally, the gate which is the resin injection port is, for example, the upper plate portion 3.
It was provided at a position corresponding to the side edge portion of, or the side plate portion 2 or the rear plate portion 4. This was done to make the traces of the gate formed on the product (first case body 5) inconspicuous as much as possible. However, since the gate position is lopsided, it can be moved into the cavity during injection molding. The filling property of the molten resin is not good, the moldability is not good especially when a large number of pieces are taken, the shrinkage rate of the molded product is uneven, and the molded product tends to be biased, and the stress concentration is low. There was a big problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to make gate traces inconspicuous, to have excellent designability, good moldability, and low stress concentration. (EN) It is an object to provide a case body for a recording medium container that is hard to be damaged even if dropped.

[0005]

In order to achieve the above object, the first aspect of the present invention is that the side plate portions are provided on both sides of the lower plate portion, and the upper plate portion is provided on these side plate portions. A case body for a recording medium container in which the rear side of the space consisting of the lower plate portion, both side plate portions and the upper plate portion is covered by the rear plate portion, and the recording medium is the surface of the upper plate portion. A gate mark is formed at a position corresponding to the center of the hub hole of the container.

According to a second aspect of the present invention, a circular boundary line is formed on the surface of the upper plate portion at a position corresponding to the inner diameter of the hub hole of the recording medium container.

[0007]

According to the first aspect of the present invention, the filling property of the molten resin into the cavity is caused by the trace of the gate formed on the surface of the upper plate portion at the position corresponding to the center of the hub hole of the recording medium container. And the gate mark is hidden by the hub rotation preventing tabs of the second case body mounted in the hub hole, and becomes inconspicuous.

Further, according to the second aspect of the present invention, the circular boundary line formed on the surface of the upper plate portion at a position corresponding to the inner diameter of the hub hole of the recording medium container is viewed from the outside. The designability of the case is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. Since the first case body of this embodiment has basically the same configuration as the first case body 5 of the conventional example,
The same reference numerals are given to the parts having the same configurations, and the description thereof will be omitted.

The difference between this embodiment and the conventional example is that the shape of the surface of the upper plate 3 is changed. That is, in the present embodiment, the center of one hub hole of the cassette (recording medium container) housed in the first case body 5 and the second case body 9 corresponds to the surface of the upper plate portion 3. A gate mark 20 is formed at a position corresponding to the circle, and a circular boundary line (circle line) 21 is also formed at a position corresponding to the inner diameter of the hub hole of the cassette. Also, at the position corresponding to the other hub hole of the cassette,
Dummy traces 22 and dummy lines 23 having the same shapes as the gate traces 20 and the boundary lines 21 are formed.

As a mold for integrally molding the first case body 5 configured as described above by injection molding, for example, as shown in FIG. 3, a fixed mold for forming the surface of the upper plate portion 3 is used. 30, a movable die 31 that can be moved toward and away from the fixed die 30, and a slide die 32 that moves in a direction orthogonal to the die opening and closing direction to form the inner surface of the first cassette body 5. The one mainly composed of is used. The fixed mold 30 has a resin passage core 3 having a gate 34 for injecting resin into the cavity 33.
5, and a dummy core 36 provided at a position symmetrical to the center line of the first case body 5 so as to face the gate 34.

The first case body 5 is formed by using the above injection mold.
2 is integrally molded, in the mold closed state, molten resin is supplied into the cavity 33 through the resin passage core 35 and the gate 34, as shown in FIG. In this case, since the gate 34 is provided at a position corresponding to the surface of the upper plate portion 3, the molten resin smoothly flows from the upper plate portion 3 to the lower plate portion 1 via the side plate portion 2 and the rear plate portion 4. And the filling property becomes extremely good.

In the first case body 5 thus obtained, the cassette is housed inside after being connected to the second case body 9. In this case, since the gate mark 20 of the first case body 5 is located at the center of the hub hole of the cassette, the hub rotation prevention formed on the bottom plate portion 6 of the second case body 9 is seen from the outside. It appears to overlap the work tabs, and therefore the gate mark 20 is inconspicuous. In addition, the first case body 5
Since the circular boundary line 21 corresponds to the inner diameter of the hub hole of the cassette, when viewed from the outside, it looks as if it overlaps with the hub hole and is not conspicuous. Further, on the surface of the upper plate portion 3 of the first case body 5, a gate mark 20 and a dummy mark 22 are formed.
Since the boundary line 21 and the dummy line 23 are line-symmetrical with respect to the center line of the first case body 5, respectively, when the cassette is not housed inside or the first case body 5 is the second case. Even when it is open against the body 9,
Balanced left and right, excellent design. Furthermore, since the moldability is good, stress concentration is less likely to occur at the gate traces 20, the strength can be improved, and damage is unlikely to occur even if dropped or the like.

In the above embodiment, the gate 34
However, the resin passage core 35 may be used instead of the dummy core 36 to form a two-point gate system.

[0015]

As described above, according to the first aspect of the present invention.
Is provided with side plate parts on both sides of the lower plate part, upper plate parts are provided on these side plate parts, and the rear side of the space consisting of the lower plate part, both side plate parts and the upper plate part is rearward. In the case body of the recording medium container covered with the plate portion, the gate mark is formed on the surface of the upper plate portion at a position corresponding to the center of the hub hole of the recording medium container. , The trace of the gate formed on the surface of the upper plate portion at the position corresponding to the center of the hub hole of the recording medium container improves the filling property of the molten resin into the cavity,
The gate traces are hidden by the hub rotation preventing tabs of the second case body mounted in the hub holes to make them inconspicuous, so that a product having good moldability, high quality, and excellent designability can be smoothly obtained. Moreover, stress concentration is unlikely to occur, and damage is unlikely to occur even if dropped.

Further, according to the second aspect of the present invention, the circular boundary line formed at the position corresponding to the inner diameter of the hub hole of the recording medium container on the surface of the upper plate portion provides a view from the outside. In this case, the designability can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of an injection molding die for manufacturing an embodiment of the present invention.

FIG. 3 is a perspective view showing an example of a cassette case.

[Explanation of symbols]

 1 Lower plate part 2 Side plate part 3 Upper plate part 4 Rear plate part 5 First case body (case body for recording medium container) 20 Gate trace 21 Boundary line (circle line)

Claims (2)

[Claims] 1. A side plate portion is provided on both sides of a lower plate portion, an upper plate portion is provided on these side plate portions, and a space consisting of the lower plate portion, both side plate portions and the upper plate portion is formed. In a recording medium container case body whose rear side is covered by a rear plate part, a gate trace is formed on the surface of the upper plate part at a position corresponding to the center of the hub hole of the recording medium container. A case body for a recording medium container characterized by: 2. The recording medium housing according to claim 1, wherein a circular boundary line is formed on the surface of the upper plate portion at a position corresponding to the inner diameter of the hub hole of the recording medium housing. Case body for dexterity.