JP2513201B2 - Molding method for cassette casing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a cassette casing, and more particularly to a method for molding a cassette casing in which a half forming the cassette casing is molded by a two-color molding method.

[Outline of Invention]

According to the present invention, two types of slide cores that are moved independently of each other are arranged in a molding die including a fixed side die and a movable side die, and the first opaque resin is movable with the fixed side die. After being injected into the cavity between the side molds, the first slide core is moved so as to form a cavity corresponding to a part of the main surface of the half of the cassette casing, and
A cavity that is continuous with this cavity and corresponds to a part of the side wall of the half of the cassette casing is formed by moving the second slide core, and a transparent second resin is injected into these mutually continuous cavities. As a result, the cassette half having the transparent portion extending from the main surface to the side wall is molded.

[Conventional technology]

Generally, in tape recorders and VTRs, tapes are made into cassettes to facilitate handling of magnetic tapes, and tape cassettes have been used. The tape cassette is one in which a magnetic tape is wound around a pair of reels and housed in a cassette casing. The cassette casing is usually constructed by combining a pair of upper and lower halves made of synthetic resin molding. By making part of such a tape cassette transparent, it is possible to check the internal state or the remaining amount of the magnetic tape.

[Problems to be solved by the invention]

In the case where a part of the cassette casing is made transparent, the method of mounting the transparent plate in which the transparent window portion is separately provided increases the number of assembling steps. Therefore, JP-A-58-212926 proposes molding a cassette casing by a two-color molding method. According to such a tape cassette, the slide core is moved after molding most of the half with the opaque resin,
By injecting a transparent resin into the resulting cavity, a cassette half having a transparent window can be obtained.

The transparent part of such a cassette casing cannot extend to the side wall part. This is because the thickness of the window portion and the height of the side wall are different, and the side wall can be obtained only by the window thickness determined by the stroke of a single slide core. That is, the conventional two-color molding method has a drawback that the shape of the molded member is limited.

The present invention has been made in view of the above problems, and provides a method for molding a cassette casing that allows a transparent portion of the main surface of the cassette casing to be extended to a side wall portion. That is the purpose.

[Means for solving problems]

The present invention relates to a cassette casing molding method for molding a half of a cassette casing by a two-color molding method, wherein the halves are moved independently of each other into a molding die composed of a stationary mold and a movable mold. A slide core of a kind is arranged, and an opaque first resin is injected into a cavity formed between the fixed-side mold and the movable-side mold, and then the first slide core is inserted into the cassette. The second slide core is moved so as to form a cavity corresponding to a part of the main surface of the casing half, and the cavity is continuous with the cavity and corresponds to a part of the side wall of the half of the cassette casing. And a transparent second resin is injected into the cavity formed by the movement of the first slide core and the second slide core. The present invention relates to a method for molding a cassette casing, which is characterized by the above.

[Action]

An opaque first resin is injected into a cavity formed between the fixed side mold and the movable side mold, and then the first slide core corresponds to a part of the main surface of the half of the cassette casing. The second slide core is moved to form a cavity that is continuous with the cavity and that corresponds to a part of the side wall of the half of the cassette casing. By injecting the transparent second resin into the cavity generated by the movement of the slide core, the half of the cassette casing whose transparent portion extends from the main surface to the side wall is molded.

〔Example〕

Hereinafter, the present invention will be described with reference to one embodiment shown in the drawings. FIG. 1A shows a mold for molding a casing of a tape cassette according to this embodiment, and the mold is a fixed-side mold.
It is composed of a movable die 10 and a movable die 11. A slide core 12 is combined with the central portion of the movable mold 11, and slide cores 13 that are moved in the axial direction are combined with the left and right lower parts. The fixed mold 10 has a gate 14 for injecting transparent resin.
Are formed.

When the casing of the tape cassette is molded by such a mold, the opaque cassette half 20 shown in FIG. 2 is made opaque by the fixed mold 10 and the movable mold 11 with the slide cores 12 and 13 closed. Mold the part. In this molding, the opaque resin 21 is passed through the gate 24 and a pair of molds 10,
It is achieved by injecting into the cavity formed between 11. And at this time slide core 12,
As shown in FIG. 2, the opaque resin 21 is cut off by 13 so as not to flow to the rear portion of the half 20.
This is the opaque resin in the first half of the half 20.
21 parts will be molded.

After this, the slide cores 12 and 13 are moved with respect to the movable mold 11. That is, as shown in FIG. 1B, the central slide core 12 is moved upward, and the left and right slide cores 13 are respectively moved laterally. This creates a new cavity between the molds 10 and 11 and in the middle.
15 will be formed. The transparent resin 22 is injected into the cavity 15 through the gate 14. As shown in FIG. 3, the resin 22 joins the transparent resin 22 molded body so as to be continuous with the opaque resin 21 molded body.
20 will be assembled. After this, as shown in FIG. 1C, the molds 10 and 11 are opened, whereby the cassette half 20 is taken out.

According to such a molding method, especially the second moving left and right
Side wall 23 of cassette half 20 by slide core 13 of
It is also possible to form the part of the transparent resin 22 as well, and the transparent window part of the cassette half 20 is expanded to the side wall part 23. That is, the central slide core 12 moves only a distance corresponding to the thickness of the main surface of the cassette half 20, while the slide core 13 has side walls.
This will form a cavity of the dimensions necessary to form 23, which allows the sidewall portion 23 to be transparent.

According to such a molding method, a core-back system enables a molded body having a shape that could be conventionally manufactured only by rotary molding. Generally, according to the rotary type molding, there are drawbacks that the molding cycle is long, it is unsuitable for mass production, and the cost is high. However, the above method can eliminate such drawbacks. Become. In addition, a multi-functional core back type two-color molding is achieved.

Next, the method of the modified example will be described with reference to FIG. According to the mold of the above-mentioned embodiment, the left and right second slide cores 13 are moved in different directions from the first slide core 12, but according to this modification, the left and right slide cores 13 are moved. 13 is designed to be moved in the same direction as the central slide core 12. Then, by increasing the strokes of the left and right slide cores 13, the stroke required to form the side wall 23 is obtained.

Therefore, according to this modification, the central core 12 is moved upward, and at the same time, the left and right cores 13 are moved by a stroke corresponding to the height of the side wall 23.
The cassette half 20 is molded by moving to a position where it comes into contact with the step 16 and then injecting the transparent resin 22 into the cavity 15. Therefore, according to this modification as well, it is possible to obtain the same effects as the above-described embodiment.

〔The invention's effect〕

As described above, according to the present invention, two types of slide cores that are moved independently of each other are arranged in a molding die including a fixed side die and a movable side die, and the fixed side die and the movable side die are arranged. Injecting an opaque first resin into the cavity formed between and, after that, moving the first slide core to form a cavity corresponding to a part of the main surface of the half of the cassette casing, and A cavity that is continuous with the cavity and corresponds to a part of the side wall of the half of the cassette casing is formed by moving the second slide core.
The transparent second resin is injected into the cavity generated by the movement of the slide core and the second slide core.

Therefore, according to the present invention, it is possible to form the transparent portion of the half forming the cassette casing so as to extend from the main surface to the side wall, and thereby the side wall can be made transparent.

Further, in such a molding method, since two types of slide cores, which are independently moved after the first resin is injected, are moved, it is possible to perform molding by a core back method. In addition to shortening the molding cycle, it is suitable for mass production and enables low-cost molding.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold showing a method of molding a cassette half according to an embodiment of the present invention, FIG. 2 is a plan view of a cassette half showing a state of molding an opaque portion, and FIG. 3 is a transparent portion. FIG. 4 is a plan view of the cassette half showing the molding state of FIG. 4, and FIG. In the reference numerals used in the drawings, 10: fixed mold 11: movable mold 12: slide core (center) 13: slide core (left and right) 14: gate 15: cavity 20: cassette Half 21 …… Opaque resin 22 …… Transparent resin.

Claims (1)

(57) [Claims] 1. Two halves constituting a cassette casing.
In a method of molding a cassette casing that is molded by a color molding method, two types of slide cores that are moved independently of each other are arranged in a molding die including a fixed side die and a movable side die, The opaque first resin is injected into the cavity formed between the mold and the movable mold, and then the first slide core is made to correspond to a part of the main surface of the half of the cassette casing. And a cavity that is continuous with the cavity and corresponds to a part of the side wall of the half of the cassette casing is formed by moving the second slide core. And a transparent second resin is injected into the cavity generated by the movement of the second slide core. Shape method.