JPS589264A - Method for manufacturing magnetic tape cassettes - Google Patents

Abstract

PURPOSE:To add a function to make enlarged indication of remaining quantity of the tape without increasing process in manufacturing by forming the body and window part of a cassette half continuously in a body. CONSTITUTION:A die is made up of a cavity 4, a core 5, and a sliding core 6. Colored molten resin 8 is poured from the gate 7 of a nozzle 9. The sliding core 6 is moved in the direction A to form a space for forming a window part. An window part 14 is formed by pouring transparent molten resin 11 into the space from a gate 10. The body 13 and window part 14 of a cassette half are bonded by heat of melting. Since a recessed part 15 for forming a magnifying lens is provided on the sliding core 6, a magnifying lens 16 is formed on the window part 14. Thereafter, the core 5 and sliding core 6 are moved in the direction B and the die is opened, and a cassette half is taken out.

Description

[Detailed description of the invention] 2.

The present invention relates to a method of manufacturing a magnetic tape cassette, and more particularly to a method of manufacturing a magnetic tape cassette in which a window with a magnifying lens for displaying the remaining amount of tape in an enlarged manner is continuously formed integrally with a cassette half body.

The cassette half (upper case) of a conventional magnetic tape cassette has a cassette half main body 1, as shown in FIG.
Windows 2 and 3 for checking the remaining amount of magnetic tape are attached by welding their respective edges 2a and 3a. Note that 2b and ab are scales indicating the remaining amount of magnetic tape.

In such a conventional manufacturing method, the cassette tape body 1 and the windows 2 and 3 are formed separately, and the number of parts required to assemble them is large, and the windows 2 and 3 are difficult to handle. It was difficult to handle because it got dirty during assembly, and it got scratched during assembly, which caused manufacturing problems.

An object of the present invention is to provide a method for manufacturing a magnetic tape cassette that can solve these manufacturing problems and add a function to enlarge and display the remaining amount of tape without adding any manufacturing steps. Seven is a7, purpose.

In order to achieve this object, the method for manufacturing a magnetic tape cassette of the present invention includes a slide core in which a recessed portion for forming a magnifying lens is provided in a portion facing the gate of a second nozzle into which a transparent second resin is injected. and the cavity, and in this state, the first resin is injected from the gate of the first nozzle into the space formed by the core and the cavity, and the cassette...
- After molding the cassette half, a transparent second resin is injected into the space created by moving the slide core through the gate of the 26th nozzle to enlarge it and integrate it with the cassette half body. A window portion with a lens is molded.

Examples of the method of the present invention will be described below with reference to FIGS. 2, 3, and 4.

Figures 2 and 3 are step diagrams for explaining one embodiment of the method of the present invention, and Figure 2 shows the process of forming the cassette half body, #! Figure 3 shows the window forming process. In the figure, 4. The molds j and 6 are a cavity, a core, and a slide core, respectively. 7 is a gate of a nozzle 9 through which colored molten resin 8 is injected, and 10 is a gate of a nozzle 12 through which colorless molten resin 11 is injected.

First, as shown in FIG. 2, the cavity 4. Core 6° Colored resin 8 forming the slide core 6 and melted from the gate 7
is injected to form the male set half main body part 13.

Next, the slide core 6 is moved in the direction A to create a space for forming the window portion 14 as shown in FIG. Transparent resin 11 is injected into this space through gate 1o to form window portion 14. The cassette half body portion 13 and the window portion 14 are bonded together by melting heat.

Since the slide core 6 is provided with a concave portion 16 for forming a magnifying lens, the magnifying lens 16 is formed in the window portion 14.

Thereafter, the core 6 and the slide core 6 move in the direction B, the mold is opened, and the cassette half is ejected.

In this case, since the cassette half is pulled and cut in game) 7.10, the resin remains attached to the tip. The rest of this resin protrudes from Ge) 7.10, so if core 6 and slide core 6
If the mold structure is such that the resin comes into contact with the gates 7 and 10, the remaining resin will become a layer that will damage the core 6 and the slide core 6. However, as is clear from the above description, the gate 7 is connected to the cassette half main body 13.
Since there is a space for molding, the gate 10 does not come into contact with the core 6, and the gate 10 should also come into contact with the slide core 6 during the molding of the cassette half body 13, but the gate 10 is expanded to the slide core 6. Since the concave portion 15 for forming the lens is provided, it does not come into contact with the slide core 6, so that neither the core 6 nor the slide core 6 are combined into one. Further, since the recess 16 for avoiding contact between the gate 10 and the slide core 6 is enlarged and used for forming the /s 16, there is no fear that an unnatural shape will remain in the completed cassette half.

FIGS. 4A and 4B are a top view and a front sectional view of a main part of a magnetic tape cassette using a cassette half formed by the above-mentioned method.

6.

As described above, the magnetic tape cassette manufacturing method of the present invention is easier to manufacture than conventional manufacturing methods because the cassette half body and the window are continuously integrally molded, and the magnifying lens is attached to the slide core. Since a recess is provided for formation, it is possible to add the function of enlarging and displaying the remaining amount of tape without adding any additional steps, and what is more, this recess allows the remaining resin attached to the gate and the slide core to be added. Since it prevents contact with the slide core, there is no risk of damage to the slide core, and its industrial value is high.

[Brief explanation of the drawings] Fig. 1 is a diagram for explaining the conventional method for manufacturing a force-stuck cutter, and Figs. 2 and 3 are process diagrams for explaining and inserting an embodiment of the method of the present invention. , 4) and 4(b) are a top view and a front sectional view of the main parts of a magnetic tape cassette using a cassette half manufactured according to the same embodiment. 4＠・−・−9 Capitie, 6・+1 battle −1・Core, 6
o...Slide core, 7,10...River/gate, 8.1
171, 7... Resin, 9.12... Nozzle, 13
...Cassette half body, 14...
Window, 16...Concave, 16...Magnifying lens O Name of agent Patent attorney Toshi Nakao tl
Figure 1 Figure 2 Figure 1--Me ■Chiang Genji, Zof, J/4

Claims (1)

[Claims] In a magnetic tape cassette integral molding method in which a cassette half consisting of a cassette half body and a window is continuously integrally molded using a mold consisting of a cavity, a core, and a slide core, a transparent second resin is injected. The slide core, which has a recess for forming a magnifying lens in the part facing the gate of the second nozzle, is brought into close contact with the cavity, and in this state, the gate of the first nozzle is inserted into the space formed by the core and the cavity. A first resin is injected to form a cassette half body, and then a transparent second resin is injected into the space created by moving the slide core through the gate of the second nozzle. A method of manufacturing a magnetic tape cassette, comprising molding a window portion with a magnifying lens that is integrated with the cassette half body portion.