JPH02226569A - Manufacture of tape cassette and its molding die - Google Patents

Abstract

PURPOSE:To easily perform the molding of a tape cassette corresponding to the presence/absence of an erroneous erasure lug with high accuracy without changing a main die by selecting the presence/absence of the molding of the erroneous erasure lug by frame switching. CONSTITUTION:The lower half of the tape cassette is molded by a fixed die 70 and a movable die 71. When an erroneous erasure prevention lug is molded, a switching frame 72 pierces through the space 81 of the die 71, and is inserted to the abutting planes 80 of the dice 70 and 71, and when no molding of the erroneous erasure prevention lug is performed, the frame 72 is switched by a corresponding switching frame by raising a die member 82 to house the head part 72a of the frame 72. By employing a method to select the presence/absence of the molding of the erroneous erasure lug by switching the switching frame without separating or switching the die, the molding and the generation of the tape cassette corresponding to the presence/absence of the erroneous erasure lug can be easily performed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for manufacturing a tape cassette and a mold thereof.

11 and 12, a conventional tape cassette, for example a tape cassette for a β-type video tape recorder, has a pair of left and right reel hubs 42 and 43 (tape reels) around which a magnetic tape 41 is wound. ), and the upper half 4 is joined to a leaf spring (not shown) that presses and holds each reel hub. In addition, in the figure, 9 is a transparent window. Also, 2
0 is an opening/closing lid on the front of the cassette.

On the back side of the lower half 5 of such a tape cassette, an erroneous erasure prevention claw 63 is integrally molded, as clearly shown in FIGS. 12 to 14. By breaking this claw 63, the recorded signal on the tape is prevented from being accidentally erased. This accidental erasure prevention claw 63 is provided in an opening 6 within an area surrounded by a wall portion 5a that is U-shaped in cross section and extends from the inner surface of the lower half 5 to the joint surface with the upper half. 8.

Recently, due to the demand for long-term or permanent storage of tape recorded signals, cassettes of the type that do not want to erase the tape recorded signals from the beginning are manufactured at the tape cassette manufacturing stage (in this case, the accidental erasure prevention claw is molded). (Unnecessary)
In this case, it is possible to retain the tape recording signal by breaking the accidental erasure prevention claw, but this will leave traces and deteriorate the appearance, so it is better not to provide the accidental erasure prevention claw from the beginning. This will solve the above trace problem. On the other hand, as an original requirement, it is also necessary to form an erroneous erasure prevention claw in order to arbitrarily record and erase tape recording signals or prevent erasure.

However, in order to manufacture these two types of tape cassettes, two types of corresponding molds may be used;
This is inappropriate because it increases the cost of manufacturing the mold.
It is also conceivable to disassemble the mold used for one type of tape cassette and reassemble it for the other type of tape cassette, but in this case, it takes time and effort to switch types.

C1 Object of the Invention The object of the present invention is to provide a method for manufacturing a tape cassette and a mold for the same, which can be easily and precisely molded according to the presence or absence of an erroneous erasure prevention claw without changing the main L-shape. It's about doing.

21 Structure of the Invention In other words, the present invention provides a method for forming a tape cassette main body using a fixed mold and a movable mold that is abutted against the fixed mold, which are replaced depending on the presence or absence of an accidental erasure prevention claw. Inserting the work piece through the tape cassette body molding space to the position of the abutment surface of the movable mold against the fixed mold;
The present invention relates to a method for manufacturing a tape cassette.

Further, the present invention has a fixed mold, a movable mold that abuts against the fixed mold, and a replacement piece that is replaced depending on the presence or absence of an accidental erasure prevention claw, and this replacement piece is used to mold the tape cassette body. The present invention also provides a mold for manufacturing a tape cassette, which is configured to be inserted through a space to a position where the movable mold abuts against the fixed mold.

E, Example The present invention will be explained in detail below.

FIG. 1 to FIG. 1θ show one embodiment of the present invention.

In this embodiment, in the β-type tape cassette described above, a mold is used that can realize the presence or absence of an erroneous erasure prevention claw without replacing or disassembling the main mold. That is, according to this mold, as shown in FIGS. 1 to 6, the main mold for molding the cassette half (lower half 5 in this case) is butted against the fixed mold 70. Movable type 7
1, and the movable type 71 further includes a replacement piece 72.
is inserted. That is, when molding the accidental erasure prevention claw 63, a replacement piece 72 as shown in the figure is assembled on the abutment surface (divided surface) 80 between the fixed mold 70 and the movable mold 71. It is inserted through the lower half molding space 81 to the position of the abutting surface 80 . Replacement piece 7
2 is inserted along the moving direction 90 of the movable mold 71.

In addition, 82 in the figure is a mold member on the movable side, and it is configured such that the head 72a of the replacement piece 72 is accommodated in a recess 83 provided therein, and in this state, the piece 72 is on the movable side. 71 with bolts (not shown; the same applies hereafter).

In particular, as shown in FIG. 9(A), the replacement piece 72 is
The tip surface 72b is an abutment surface for the fixed mold,
The inner side thereof is a molding recess 84 corresponding to an erroneous erasure prevention claw. A notch 85 that communicates this recess 84 with the lower half molding space 81 described above is provided at the position of the connecting portion 7.8 (see FIGS. 12 to 14). In addition, each of the abutment surfaces 80.72 described above
In b, it is desirable that each mold 70, 71 and the piece 72 be finished with a mirror finish in order to prevent leakage or intrusion of the injected resin.

As described above, by attaching the replacement piece 72 and injecting the resin into the molding space 81, the resin is transferred to the piece 72.
It can be introduced into the frame recess 84 through the notch 85 . After the resin has solidified, the piece 72 is pulled out together with the movable mold 71 in the same direction to separate it from the fixed mold 70, and the product (lower half) is further separated from the movable mold using an ejector (not shown).

As a result, as shown in FIG. 9(B), a connecting portion 7. is formed at the position of the notch 85 corresponding to the shape of the piece 72.
An erroneous erasure prevention claw 63 is formed integrally with the lower half 5 at the position of the concave portion 84 through the hole 8 .

On the other hand, when manufacturing a type of cassette without the accidental erasure prevention claw 63, the frame 72 is removed from the movable mold 71,
Another piece 72' as shown in FIG. 7 is inserted and fixed in the same position in the same manner as described above. The piece 72' replaced in this way is different from the piece 72 described above, and is different from the piece 72 described above.
), the recess 84 is entirely surrounded by walls. That is, there is no notch 85, and resin is not injected into the recess 84. Therefore, Fig. 10 (B
) can easily manufacture the type of lower half 5 that does not have a claw to prevent accidental erasure.

As mentioned above, replace the replacement pieces 72 and 72' with the movable
1 and replace only the piece as necessary (however, there is no need to disassemble the movable mold 71 itself), it is possible to select whether or not to mold the accidental erasure prevention claw.
To perform molding work without disassembling or replacing the main mold and with the main mold attached to the molding machine. Therefore, it is possible to very quickly switch operations depending on the presence or absence of the erroneous erasure prevention claw, and it is also possible to greatly reduce the cost required for molds and the like. A tape cassette without the accidental erasure prevention claw 63 has a good appearance because there is no trace of the broken claw as described above.

Since the pieces 72 and 72' used in molding are fixed to the movable mold 71 between the fixed mold 70 and the movable mold 71, they can be easily attached and removed.

Since the pieces 72 and 72' can be manufactured separately, the accuracy of forming the erroneous erasure prevention claw 63 can also be improved.

Furthermore, since the joining surfaces of each of the above-mentioned types are mirror-finished, resin does not leak from the joining surfaces, and the occurrence of paris can be minimized.

Although separate molds may be used to manufacture the above-mentioned pieces 72 and 72', the pieces 72' having the shape shown in FIG. The piece 72 may be partially cut according to the above-described notch 85. In this case, it is easier to form the pieces, and both pieces 7
2.72' can be easily manufactured.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, various shapes and combinations of the fixed type and movable type, methods of moving or sliding the movable type, etc. can be adopted. Also,
The shape and method of assembling the above-mentioned replacement piece can be changed in various ways, and for example, the structure may be such that it is clamped and fixed between the molds 70 and 71 without using the above-mentioned bolts. At least the abutting side of the replacement piece? 2b or at least the abutment surface of the movable mold 71 is desirably made into a mirror surface. in this case,
It is preferable to make the surface of the fixed mold 70 mirror-finished, but even if the surface is moderately roughened, the surface of the molded lower half can be used as a roughened design.

However, it is better to have a mirror surface in areas other than the molding space.

Due to the roughening described above, some resin may enter the portion of the accidental erasure prevention claw (specifically, the area of the opening 6), but this can be easily removed because it is very thin.
Regarding the above-mentioned piece 72', the recess 84 does not necessarily need to be provided, and the entire tip surface may be solid (flat). A frame? The insertion or separation direction of 2.72' is preferably perpendicular to the abutment surface 80 as described above, but this may be varied depending on the shape of the cassette.

9. Effects of the Invention As described above, the present invention selects whether or not to form the accidental erasure prevention claw by exchanging the pieces, so there is no need to disassemble or replace the main mold, and the main mold can be installed in the molding machine. Molding work can be performed with the mold attached, and therefore the work can be changed very quickly depending on the presence or absence of the accidental erasure prevention claw, and the cost required for the mold etc. can be greatly reduced.

Furthermore, since the pieces used during the production process can be attached and removed separately from the movable mold, the precision of forming the accidental erasure prevention claws is improved, and the pieces are easy to attach and remove, making it easy to attach and remove other parts. Does not affect molding.

[Brief explanation of the drawing]

1 to 10 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view of the main part of the mold, FIG. 2 is a cross-sectional view taken along line nn in FIG. 1, and FIG. The figure is a cross-sectional view taken along line mm in Figure 1, Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2, Figure 5 is a cross-sectional view taken along line V-V in Figure 2, and Figure 6 is a cross-sectional view taken along line V-V in Figure 2. (corresponding to the molded product in Fig. 14), Fig. 7 is a sectional view similar to Fig. 1 of the mold with the piece replaced, Fig. 8 is the line ■-■ of Fig. 7. 9 (A) and 10 (A) are perspective views of the replacement pieces, and Figures 9 (B) and 10 (B) are the bottom molded using each replacement piece. FIG. 3 is a sectional view of each main part of the half. 11 to 14 show conventional examples, and the first
Figure 1 is a plan view of a tape cassette for a video tape recorder, Figure 12 is a rear view of a part of the cassette, Figure 13 is an internal view of the main parts of the lower half, and Figure 14 is a diagram showing XIV-XIV of Figure 13. FIG. In addition, in the symbols shown in the drawings, 4...--... Upper half 5...-- Lower half 41...・Magnetic tape 63...
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fixed type 71 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Movable type 72.72 '・ ・ ・ ・ ・2b , 80・−・−・−・Abutment surface 81・−
. . . Molding space 84 --- Recessed portion 85 --- Notch.

Claims (1)

[Claims] 1. When molding a tape cassette body using a fixed mold and a movable mold that is abutted against the fixed mold, a replacement piece is replaced depending on the presence or absence of an accidental erasure prevention claw. A method of manufacturing a tape cassette, the tape cassette being inserted through a molding space of a tape cassette body to a position where the movable mold abuts against the fixed part. 2. A fixed mold, a movable mold that abuts against this fixed mold,
and a replacement piece that is replaced depending on the presence or absence of the accidental erasure prevention claw, and this replacement piece is inserted through the tape cassette body molding space to the position of the abutment surface of the movable mold against the fixed mold. A mold for manufacturing tape cassettes configured as follows.