JP2000276870A - Magnetic tape cassette and metallic mold for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good magnetic tape cassette having no mounting failure and a metallic mold for the same. SOLUTION: This magnetic tape cassette is constructed in such a manner that the upper screw boss 21 of an upper cassette half 20 is fitted in the boss housing hole 13 of a lower screw boss integrally provided in the side wall 11 of a lower cassette half 10, and by engaging a screw 30 inserted into the screw inserting hole 14 of the lower screw boss 12 with the upper screw boss 21 of the upper cassette half 200. The upper and lower cassette halves 10 and 20 are fixed to each other. The height of the lower screw boss 12 of the lower cassette half 10 is set equal to/higher than that of the side wall 11 of the lower cassette half 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette such as a digital video cassette (DVC) in which a pair of tape reels around which a magnetic tape is wound are rotatably housed in a cassette case composed of upper and lower cassette halves. More specifically, the present invention relates to a magnetic tape cassette having a screw boss for fixing upper and lower cassette halves with screws, and a mold for the magnetic tape cassette.

[0002]

2. Description of the Related Art In general, in audio equipment, video equipment and the like, a magnetic tape cassette for recording / reproducing a magnetic tape wound around a pair of tape reels so as to be able to run in a cassette case is often used. .

FIG. 3 shows a magnetic tape cassette 50 used for a conventional DVC. The cassette case 51 of the magnetic tape cassette 50 includes an upper cassette half 52 and a lower cassette half 53. An opening 54 is formed in the center of the lower cassette half 53 on the near side in FIG. 3, and tape guides 55 are provided on both sides of the opening 54. The upper cassette half 52 includes an outer lid 56 and an inner lid 5.
7 and a top lid 58 are attached to be openable and closable, respectively.

[0004] The magnetic tape 59 comprises a pair of tape reels 6.
0 and is rotatably loaded in the lower cassette half 53. The magnetic tape 59 is guided by the tape guide 55 and is stretched at the opening 54. Then, the lower cassette half 53 is covered with the upper cassette half 52, and the magnetic tape 59 exposed at the opening 54 of the lower cassette half 53 is attached to the outer lid 56 and the inner lid 57.
4, and the upper cassette half 52 is integrated by screws 61 inserted from screw insertion holes 53a of the lower cassette half 53, as shown in FIG.

[0005]

The cassette case 51 of the conventional magnetic tape cassette 50 described above.
As shown in FIG. 5, a boss 62 formed on the upper cassette half 52 is replaced with a boss 63 formed on the lower cassette half 53.
Of the upper cassette half 5 is inserted into the screw insertion hole 53a of the lower cassette half 53.
The upper and lower cassette halves 52 and 53 are connected to each other by being screwed into a hole 62a of the second boss 62.

In the cassette case 51, a boss 63 is provided integrally with a side wall 64 of the lower cassette half, and its height is lower than the side wall 64, as shown in FIG. Is formed. The cassette case 51 is injection-molded by a split mold 70 including an upper mold 71 and a lower mold 72 as shown in FIG.
In particular, in the cavity 71a of the upper die 71 forming the portion B of the boss 63, the air staying there is compressed without being able to escape quickly when the molten resin flows, resulting in poor filling (short shot). There is a fear that if the resin is continuously molded in this state, the carbides adhere to the mold surface due to the gas at the time of the resin flowing, and the defective filling is further increased.

To solve such a problem, FIG.
As shown in (1), it is conceivable to use the insert 73, but the C portion of the upper mold 71 becomes thinner, and the durability of the mold is reduced, which is difficult to realize.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to provide a good magnetic tape cassette free from defective filling and a mold for the magnetic tape cassette.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to dispose an upper screw boss having a screw screw hole at the center thereof in the upper cassette half, and to integrally form the lower cassette half with an upright wall of the lower cassette half. And a lower screw boss having a boss receiving hole for fitting the upper screw boss in the center is provided,
A pair of tape reels around which a magnetic tape is wound are rotatably accommodated in a cassette case composed of the upper and lower cassette halves, and the upper boss boss of the lower cassette half is accommodated in the upper boss of the upper cassette half. A magnetic tape cassette for fixing the upper and lower cassette halves to each other by screwing a screw inserted into the lower screw boss into the screw screw-in hole of the upper screw boss of the upper cassette half; The height of the lower screw boss of the half is made equal to or higher than the height of the upright wall of the lower cassette half.

According to this structure, even if the boss receiving hole for inserting the screw boss of the upper cassette half of the lower die is formed by nesting, a thin portion does not occur in the upper die, so that the durability of the die is improved. It is possible to obtain a high-quality lower cassette half free from poor filling and the like without lowering the performance.

It is another object of the present invention to dispose an upper screw boss having a screw screw hole at the center thereof in the upper cassette half, and to integrally form the lower cassette half with the upright wall of the lower cassette half. A lower screw boss having a boss receiving hole into which the upper screw boss is fitted, and a pair of tape reels wound with a magnetic tape are rotatably stored in a cassette case composed of the upper and lower cassette halves. The upper screw boss of the cassette half is fitted with the boss receiving hole of the lower screw boss of the lower cassette half,
A mold for molding the lower half case of the magnetic tape cassette for fixing the upper and lower cassette halves to each other by screwing a screw inserted into the lower screw boss into the screw screw hole of the upper screw boss of the upper cassette half; The height of the lower screw boss of the lower cassette half is equal to or greater than the height of the upright wall of the lower cassette half, and the mold for forming the boss receiving hole of the lower screw boss is a nested type. This is achieved by a characteristic magnetic tape cassette mold.

According to this structure, the boss receiving hole of the lower screw boss is formed by nesting, so that the air staying in the cavity of the upper mold escapes quickly when the molten resin flows from the gap around the nest. As a result, a good quality lower cassette half can be obtained without causing defective filling. The upright wall in the present invention is a side wall that defines the lower half case, a rib that stands inside the lower half case, or the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a main part of a magnetic tape cassette according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a mold for molding the main part of the magnetic tape cassette of FIG.

FIG. 1 shows a portion corresponding to the portion A in FIG. In the magnetic tape cassette according to the present invention,
The cassette case is constituted by a lower cassette half 10 and an upper cassette case 20, and a lower screw boss 12 is integrally provided on a side wall 11 of the lower cassette half 10. The height of the screw boss 12 is flush with the side wall 11, and a boss accommodation hole 13 for accommodating the upper screw boss 21 of the upper cassette half 20 is formed at the center thereof. Has a screw insertion hole 14 formed therein. On the other hand, screw boss 2 of upper cassette half 20
A screw screw insertion hole 22 for screwing a screw 30 is formed in 1.

The cassette case of the magnetic tape cassette is mounted on the screw boss 21 of the upper cassette half 20 with the lower cassette half 10 facing upward.
The screw 30 inserted through the screw insertion hole 14 of the lower cassette half 10 is screwed into the screw screw hole 22 of the screw boss 21 of the upper cassette half 20.
, The lower cassette half 10 and the upper cassette half 20 are connected.

A mold 40 for molding the lower cassette half 10
As shown in FIG. 2, the upper mold 41 includes an upper mold 41 and a lower mold 42, and a nest 43 is attached to the upper mold 41.
The upper die 41 forms the side wall 11 of the lower cassette half 10 and the outer periphery of the screw boss 12, and the nest 43 forms the boss receiving hole 13 and the screw insertion hole 14 of the screw boss 12.
Is formed. The outer surface of the lower cassette half 10 is formed by the lower mold 42.

According to such a mold 40, the screw boss 1
The air stagnating in the cavity defining the upper end D of the mold 2 is quickly escaped through the gap between the nest 43 and the upper mold 41 when the molten resin flows, so that poor quality can be obtained without causing poor filling. Lower cassette half 10 can be obtained.

In the above embodiment, the upper surface of the screw boss 12 is flush with the side wall 11, but the upper surface of the screw boss 12 may be higher than the height of the side wall 11. The positions of the screw bosses 12 may be not only the corners of the lower cassette half 10 but also other places. In other words, the screw bosses 12 are provided integrally with the side walls 11 and the ribs provided on the bottom surface.
If it is, the present invention can be applied, and its position does not matter.

[0019]

As described above, in the magnetic tape cassette according to the present invention, the height of the lower screw boss of the lower cassette half is equal to or higher than the height of the standing wall of the lower cassette half. According to this magnetic tape cassette, even if the boss receiving hole for inserting the screw boss of the upper cassette half in the lower die is formed by nesting, a thin portion does not occur in the upper die. It is possible to obtain a high quality lower cassette half without lowering and without defective filling.

Further, in the magnetic tape cassette mold of the present invention, the height of the lower screw boss of the lower cassette half is formed to be equal to or higher than the height of the standing wall of the lower cassette half, and the boss receiving hole of the lower screw boss is nested. It is formed. According to this magnetic tape cassette mold, the boss housing hole of the lower screw boss is formed by nesting, so that the air stagnating in the cavity of the upper mold is released from the gap around the nest when the molten resin flows. Since it can escape quickly, it is possible to obtain a high quality lower cassette half without causing defective filling.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of a magnetic tape cassette according to the present invention.

FIG. 2 is a cross-sectional view showing a mold for molding a main part of one embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a conventional magnetic tape cassette to which the present invention is applied.

FIG. 4 is a perspective view showing an assembled state of a conventional magnetic tape cassette to which the present invention is applied.

FIG. 5 is an enlarged perspective view showing a portion A in FIG. 3;

FIG. 6 is a sectional view showing a mold for molding the portion shown in FIG. 5;

FIG. 7 is a sectional view showing a case where a nest is used as a mold for molding the portion shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lower cassette half 11 Side wall 12 Screw boss 13 Boss accommodation hole 14 Screw insertion hole 20 Upper cassette half 21 Screw boss 22 Screw screw hole 30 Screw 40 Die 41 Upper die 42 Lower die 43 Nesting

Claims (2)

[Claims] 1. An upper screw boss having a screw screw hole at the center thereof is provided in the upper cassette half, and the upper screw boss is fitted into the lower cassette half integrally with the upright wall of the lower cassette half and at the center. A lower screw boss having a boss receiving hole is provided, and a pair of tape reels around which a magnetic tape is wound are rotatably housed in a cassette case composed of the upper and lower cassette halves. The boss receiving hole of the lower screw boss of the lower cassette half is fitted, and a screw inserted into the lower screw boss is screwed into the screw screw hole of the upper screw boss of the upper cassette half. A height of the lower screw boss of the lower cassette half, and a height of the vertical wall of the lower cassette half. Magnetic tape cassettes, characterized in that it has the same or higher To be. 2. An upper screw boss having a screw screw hole at the center thereof is disposed in the upper cassette half, and the upper screw boss is fitted into the lower cassette half integrally with the upright wall of the lower cassette half and at the center. A lower screw boss having a boss receiving hole is provided, and a pair of tape reels around which a magnetic tape is wound are rotatably housed in a cassette case composed of the upper and lower cassette halves. The upper and lower cassette halves are engaged by fitting the boss receiving holes of the lower screw bosses of the lower cassette half and screwing the screws inserted into the lower screw bosses into the screw screw holes of the upper screw bosses of the upper cassette half. A mold for molding the lower half case of the magnetic tape cassette to be fixed to each other, wherein the height of the lower screw boss of the lower cassette half is The formed above the same as the height of the upright wall of the lower cassette half,
A mold for forming the boss receiving hole of the lower screw boss is a nested type, and a mold for a magnetic tape cassette.