JPH01315089A - Molding method for tape cassette - Google Patents

Abstract

PURPOSE:To obtain a tape cassette having satisfactory strength without deteriorating external appearance by forming recessing/projecting parts at a part or the whole of an intermediate part formed vertically on the junction surface between transparent and opaque resin parts to match both parts with each other. CONSTITUTION:A matching projecting part 21 having the height of about 0.005-0.3mm, for example, is provided to a part of an intermediate part formed vertically on the junction layer between the transparent parts 5 of case half bodies 2 and 3 of a tape cassette 1. At the same time, a matching recess part 22 is added to the part 5 in response to the part 21. Thus the part 21 of the bodies 2 and 3 is coupled with the part 22 of the part 5 and then formed integrally by welding at the injection molding. Thus the satisfactory strength is obtained even with the combination of materials having the comparatively small thickness of the part 5 or different types of materials which are hard to join with each other. In such a way, a tape cassette having the satisfactory strength is obtained without deteriorating the external appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of forming a tape cassette into which magnetic tape is loaded.

[Summary of the invention]

The present invention relates to a method for molding a tape cassette into which a magnetic tape is loaded, and the present invention relates to a method for molding a tape cassette that is integrally formed by injection molding through a molding process using a colored opaque resin and a molding process using a second colored transparent resin. In the method, a convex portion is provided on the transparent resin or the opaque resin in part or all of the intermediate portion in the vertical direction of the bonding surface between the transparent resin and the opaque resin, and a convex portion is provided on the opaque resin or the transparent resin corresponding to the convex portion. The transparent part and the opaque part are integrally molded with sufficient bonding strength without spoiling the appearance by providing a recess that fits into the transparent part and the opaque part.

[Conventional technology]

Previously, a tape cassette as shown in FIG. 3 has been proposed in which one reel hub is provided with a transparent portion having a relatively large area so that the maximum amount of magnetic tape wound up can be easily viewed. That is, in FIG. 3, (1) indicates a tape cassette, and (1) of this tape cassette is constituted by a pair of half casings (2) and (3) joined together by screws. These housing halves (2) and (3) are each made of an opaque thermoplastic resin, such as styrene resin. (4) is a magnetic tape loaded into this tape cassette (1).

(5) Magnetic tape (4) wound around the beam hub (6)
) is a transparent part made of a transparent thermoplastic resin, such as styrene resin, which is provided over a range larger than the maximum winding diameter of the tape cassette (1) through this transparent part (5).
The magnetic tape (4) wound around the inner wheel hub (6) is easily visible. This transparent part (5
) is provided with a pair of reel shaft insertion holes (7a) and (7b) into which the reel hub (6) is loosely fitted for rotation. (8) is a central opening provided on the front side of the tape cassette (1), and the recording/playback head is inserted into the front side of the tape cassette (1) through this central opening (8) during recording or playback. It is done as if it were inserted. In addition, (9a) and (9b) are small windows arranged at symmetrical positions of the central opening (8), (10a) and (lot
l) are openings located on the outside of the small windows (9a) and (9b), respectively, at symmetrical positions with respect to the central opening (8);
(Ha), (llb) and (12a>, (12b)
are a capstan insertion hole and a positioning hole, respectively.

At present, such tape cassette tape cassettes (1)
When manufacturing by injection molding, as shown in FIG. ) into the first cavity (16) forming the casing half (2), (
After injection molding 3), the movable mold (1
5) to form a second cavity (18) forming the transparent part (5), and a transparent resin is injected into the second cavity (18) through the gate (19) to form the transparent part (5). Part (5) is injection molded, and the heat and injection pressure during injection molding of this transparent part (5) cause the casing halves (2) and (3
) and the transparent part (5) are formed into a negative body.

[Problem to be solved by the invention]

By the way, as mentioned above, the transparent part (5) of this tape cassette is formed by the casing halves (2) and (3) due to the heat and injection pressure of the molten transparent resin when injection molding the transparent B (5).
However, if the border between the transparent part (5) and the case halves (2) and (3) is made flat as shown in Figure 6, the transparent part (5) In cases where the transparent part (5) and the case halves (2) and (3) are made of a combination of different materials that are difficult to bond, the transparent part (5) and the case halves (2) and (3) may not be thick enough. (2) and (3) are insufficiently bonded, and when in use, the transparent part (5) is attached to the case half (2),
There was an inconvenience that it fell outside of (3).

For this reason, as shown in Fig. 7, the transparent part (5) and the case half (2
) and (3) are made in a step-like manner to increase the bonding area and thereby obtain sufficient bonding strength. In this case, as shown in Figure 8 (movable mold (15
) An annular step-forming convex portion (15a) is provided at a predetermined interval from the end around the upper surface of the case half (2), (
When the movable mold (15) is moved to close the second cavity (18) to injection mold 3), the annular step-forming convex 1s (15a) is inserted into the upper fixed mold (13).
The boundary between the first cavity (16) and the movable mold (15) is shaped like a step so that the half body (2) formed in the first cavity (16), ( 3
) by making the boundary surface with the transparent part (5) step-like, so that the transparent part (5) and the casing half (2) are formed subsequently,
The boundary with (3) is stepped.

By the way, in the tape cassette injection-molded in this way, an unnatural annular groove is formed on the inner surface of the transparent part (5) as a trace of the step-forming convex part (15a), as shown by the dotted line in FIG. (20), and this annular groove (20) impairs the appearance of the tape cassette.

The present invention has been made in view of the above, and its purpose is to provide a method for molding a tape cassette that can integrally mold a transparent part and a casing half with sufficient bonding strength without impairing the appearance. This is what I did.

[Means to solve the problem]

An example of the method for molding the tape cassette of the present invention is shown in FIG. 1, in which injection molding is performed using a first color opaque resin and a second color transparent resin. Tape cassette made like this (1)
In the molding method, a convex portion (21) is provided on the transparent resin or the opaque resin in part or all of the vertically intermediate portion of the joint surface of the transparent resin and the opaque resin, and the convex portion (21) is provided on the transparent resin or the opaque resin.
Corresponding to 21), a convex portion (21) is formed on the opaque resin or transparent resin.
) is provided with a recess (22) that fits into the hole.

[Effect]

According to the method for molding a tape cassette of the present invention, a convex portion is provided in the vertically intermediate portion of the joint surface with the transparent resin or the opaque resin, and the convex portion is fitted into the convex portion of the opaque resin or the transparent resin in correspondence with the convex portion. According to the method for molding the tape cassette of the present invention, the transparent resin window and the half-casing can be integrally molded with sufficient bonding strength without impairing the appearance. You can get what you can.

〔Example〕

Hereinafter, one embodiment of the tape cassette of the present invention will be described with reference to FIGS. 1 and 2.

In FIGS. 1 and 2, parts corresponding to those in FIGS. 3 to 5 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, the case half (2) is shown in FIG.

A fitting protrusion (21) with a height of, for example, about 0.005 to 0.3n++n is provided in a part of the vertically intermediate portion of the joining surface with the transparent part (5) of (3), and this fitting protrusion Part (21)
A fitting port II that fits into this fitting convex portion (21) corresponding to
(22) is provided on the transparent part (5). The rest of the structure is the same as that of the tape cassette (1) shown in FIGS. 3 to 5 above.

According to such a tape cassette (1), a movable mold (15
) is provided with a fitting protrusion forming recess (23) at a predetermined position on the surface forming the first cavity (16), that is, at a position corresponding to the fitting protrusion (21), and as shown in FIG. Type (15
) with the second cavity (18) closed, the molten opaque resin is injected into the first cavity (16) through the gage) (17) to form a housing having a fitting convex portion (21). The transparent parts (5) are obtained by moving the movable mold (15) as shown in FIGS. 5 and 2.
), and a transparent resin was injected into the second cavity (18) through the gate (19) to fit into the fitting convex part (21). The transparent part (5) having the fitting recess (22) is the case half (2)
, (3) - formed into a body. In this way, half boxes (2) and (3) are obtained, and these half boxes (2),
(3) by assembling the tape cassette (1).
) is obtained.

In such a tape cassette (1), the case half (2
), the fitting convex part 21 of (3) and the fitting recess (22) of the transparent part (5) are in a fitted state, and the case half (2),
(3) and the transparent part (5) are integrally formed by welding during injection molding and fitting of the fitting convex part (21) and the fitting recess (22), and the thickness of the transparent part (5) Even for items that are relatively thin or that combine dissimilar materials that are difficult to join,
Sufficient bonding strength can be obtained.

As described above, according to the molding method (1) of the tape force set in this example, for example, the opaque resin has a convex portion (
21) and a concave part (22) that fits into the convex part (21) in the transparent resin, for example, corresponding to the convex part (21), so that an unnatural groove (20) is formed in the transparent resin part. The transparent part (5) and the opaque casing half (2) are bonded with sufficient bonding strength without causing any damage to the appearance.
3) can be molded into one piece.

Further, in the above embodiment, the case where the fitting protrusion I (21) and the fitting recess (22) are provided in a part of the middle part of the joint surface is described, but it is also possible to provide them in the entire middle part of the joint surface. It is easy to understand that the same effects as in the above-mentioned embodiments can be obtained.

Furthermore, in the above embodiment, the fitting protrusions (21) are provided on the case halves (2) and (3), and the fitting opening 1 is provided on the transparent part (5) side.
Although we have described the case in which the casing halves (2) and (3) are provided with a fitting concave portion, and a fitting convex portion is provided on the transparent portion (5) side, conversely It is easy to understand that even if .

It goes without saying that the present invention is not limited to the above-described embodiments, and can take various other configurations without departing from the gist of the present invention.

〔Effect of the invention〕

According to the tape cassette molding method of the present invention, the tape cassette includes a transparent part and an opaque part, and the transparent part and the opaque part are integrally molded.
Providing a convex part on the transparent part or the opaque part in part or all of the intermediate part in the vertical direction of the joining surface of the transparent part and the opaque part, and fitting the convex part on the opaque part or the transparent part in correspondence with this convex part. Since the concave portion is provided, there is an advantage that the transparent portion and the opaque portion can be integrally molded with sufficient bonding strength without impairing the appearance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the main part of the tape cassette of the present invention, Fig. 2 is a sectional view explaining the manufacturing process of Fig. 1, and Fig. 3 is a sectional view showing a conventional relatively large transparent part. FIGS. 4 and 5 are route diagrams for explaining the manufacturing process of FIG. 3, and FIGS. 6 and 7 are examples of main parts of a conventional tape cassette, respectively. 8 is a sectional view for explaining the manufacturing process of FIG. 7,
FIG. 9 is a plan view showing the tape cassette manufactured according to FIG. 8. (1) is a tape cassette, (2) and (3) are half boxes each serving as an opaque part, (4) is a magnetic tape, (5) is a transparent part, (13), (14) and <15) are an upper fixed mold, a lower fixed mold, and a movable mold, respectively, (21) is a fitting protrusion, and (22) is a fitting recess. Agent Hide Matsukuma MoritaFigure 1Figure 2Figure 3Figure 5

Claims (1)

[Claims] In a method for molding a tape cassette which is integrally molded by injection molding through a molding process using a first color opaque resin and a molding process using a second color transparent resin, the transparent resin and the opaque resin are joined together. A convex portion is provided in the transparent resin or the opaque resin in part or all of the intermediate portion in the vertical direction of the surface, and a concave portion that fits in the convex portion is provided in the opaque resin or the transparent resin corresponding to the convex portion. A method for forming a tape cassette, characterized in that a tape cassette is provided.