JP2765197B2 - Audio cassette half - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio cassette half in which a case capable of accommodating a magnetic tape is integrally formed with a primary injection material and a secondary injection material.

[Prior Art] Generally, an audio tape cassette is known in which a window portion for forming a visible magnetic tape is formed. In this case, a method of simultaneously molding using two types of resins, that is, providing a window in a head corresponding portion is provided. A frame formed by a primary injection material together with a symbol forming portion representing the A surface or the B surface of the magnetic tape formed on the outer surface of the frame portion through the side gate, and a tape provided on the case body portion It has been adopted that the visible window is integrally formed with a secondary injection material. In the molding method, a core is slidably provided in the cavity, and the core is projected during molding of the frame portion and abuts against the other mold to partition the frame portion forming space portion and the window portion forming space portion. The primary injection material and the secondary injection material were sequentially filled to form a cassette half having a window.

[Problems to be Solved by the Invention] In the cassette half of the prior art described above, there is a gate mark at the time of molding in a head corresponding portion, and a finishing process for cutting off or shaving off the gate mark is required. In addition, there is a problem that the appearance is bad because it remains as a scar on the surface. In addition, when the tape cassette is stored in the cassette case, there is also a problem that the scar is worn away and chips are generated from the scar and the chips are attached to the tape.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an audio cassette half excellent in appearance without a gate trace at the time of molding at a head corresponding portion.

Means for Solving the Problems In order to achieve the above object, an audio cassette half of the present invention has a symbol forming portion formed in a frame portion for accommodating a magnetic tape, a mark portion of a direct gate for a primary injection material. It is formed by:

[Operation] In the audio cassette half of the present invention, the mark formation portion is provided by the trace path of the direct gate, so that the scar etc. in the head corresponding portion can be wiped out.

Embodiment An embodiment of the present invention will be specifically described below with reference to the drawings.

As shown in FIG. 1, an audio cassette capable of storing a magnetic tape (not shown) includes an upper audio cassette half (hereinafter, referred to as "cassette half") 1 and a lower audio cassette half (hereinafter, "cassette half"). The upper and lower cassette halves 1 and 2 each have a head corresponding portion 3 formed on one side thereof, and have a first triangular symbol representing the surface A of the magnetic tape formed on the outer surface. The portion 4 is formed by a trace of a first direct gate described later. A window 6 for visualizing the magnetic tape is formed substantially at the center of the frame 5, and a hub hole 7 is formed in the window 6. Similarly, the lower cassette half 2 has, on its outer surface, a round second symbol forming portion 8 representing the surface B of the magnetic tape formed in the frame portion 9.

2 to 5 show an example for forming the cassette halves 1 and 2. In these figures, reference numeral 10 denotes a female fixed mold plate. It is mounted on the fixed mounting plate 12 via the plates 11, 11A, 11B. In addition, a movable mold plate which is a male mold facing the fixed mold plate 10.
A movable plate 13 is mounted on a movable mounting plate 16 via movable receiving plates 14, 14A, 14B and a spacer block 15. Engraved surfaces for forming the outer and inner surfaces of the cassette halves 1 and 2 are formed on the opposing surfaces of the template plates 10 and 13, respectively, and cavities 17 are provided.

As shown in FIG. 5, a cavity 17 for molding the upper cassette half 1 is formed.
A and a pair of cavities 17B for molding the lower cassette half 2 are formed as a pair, and two sets are formed. Further, three groups are provided to form a total of twelve cavities 17A and 17B.

A core-back assembly 18 penetrates through the movable mold plate 13 and the movable receiving plate 14 and has a fixed mold plate 10
It is provided movably in the direction. The core bag assembly 18 is composed of a core type body 19 for forming the window 6 of the cassette half 1 and a receiver 20 supporting the core type body 19. It is connected to the piston rod 22 of the hydraulic cylinder 21 disposed inside the movable receiving plate 14B, and when the mold is closed, by advancing the piston rod 22 of the hydraulic cylinder 21, the distal end surface of the core mold 19 is By contacting the fixed mold plate 10 and retracting the piston rod 22, the tip surface of the core mold body 19 is configured to be substantially the same as the engraved surface of the movable mold plate 13.

The fixed mounting plate 12 has a pair of locating rings 23, 24.
Are mounted, and sprue bushes 25 and 26 are inserted through the fixed mounting plate 12. The manifold block 28 provided with the sprue bushes 25 and 26 and the manifold 27, the fixed receiving plate 11, and the two mold plates 10 and 13 respectively have a first passage 29 and a secondary passage for the primary injection material (opaque). A second passage 30 for the injection material (transparent) is formed. still,
The length of the manifold 27 can be supplied equally to the primary side and the secondary side from the branch point. Further, a first sprue 31 is connected to an end of the first passage 29, and the first sprue 31 is formed in a triangular shape corresponding to the first symbol forming part 4 to form a first direct gate 32. You. The first sprue 31 is provided with a first torpedo 34 having a triangular cross section for sealing the first gate 33, and the torpedo 34 is formed by air pressure from an air cylinder (not shown) during molding. At the time of injection, the gate rises and retreats to open the first gate 33, and simultaneously with the completion of injection, the first gate
33 is provided to close. The second passage 30
A second sprue 35 is connected to the tip of
The second gate 36 of the sprue 35 has a window frame forming space 38 formed in the frame forming space 37 as the core mold 19 is retracted.
And a second direct gate 39 is formed substantially at the center of the second direct gate 39. Further, the second sprue 35 is provided with a second torpedo 40 for sealing the second gate 36. The first direct gate 32 corresponding to the second symbol forming section 8
The first gate 33A and the first tope of A have a circular cross section.

Next, a method of molding the cassette halves 1 and 2 using the two-color molding die configured as described above will be described.

First, the leading end surface of the core mold 19 is brought into contact with the engraved surface of the fixed mold plate 10 simultaneously with the start of mold clamping. In this state, the first nozzle
32, the first gate 32A is opened by the first torpedo 34,
The primary injection material A that has passed through the passage 29 is
The portion corresponding to the symbol forming portion 4 on the outer surface of the frame portion 5 is filled into the frame portion forming space portion 37 of the cavity 17, whereby the frame portion 5 is formed. Thereafter, the first torpedo 34 closes the first gate 33, so that the first symbol forming section 4 becomes the first symbol.
It is formed by the trace of the gate 33.

Next, when the piston rod 22 of the hydraulic cylinder 21 is retracted, the core body 19 returns, and the front end surface of the core body 19 becomes substantially the same as the engraved surface of the movable mold plate 13, and the front end surface and the engraved surface A window forming space 38 is formed therebetween. In this state, the second gate 36 is opened by the second torpedo 40, and the secondary injection material B passing through the second passage 30 is moved from a portion corresponding to the outer surface of the window 6 of the cassette half 1 to the window forming space. After the portion 38 has been filled, the second gate 36
And the cassette half 1 is formed in two colors.

Even when the lower cassette half 2 is formed, the second symbol forming portion 8 is formed by the trace of the first gate 33A, similarly to the upper cassette half 1.

After the solidification, the mold opening is started and the cassette halves 1 and 2 are released.

According to the cassette half 1 described above, the first symbol forming portion 4 provided on the outer surface of the frame portion 5 is
With no trace of the gate in the head corresponding portion 3, the head corresponding portion 3 is excellent in appearance, and there is no possibility of generating chips or the like when the tape cassette is stored in the cassette case, and the quality can be improved. .

Note that the present invention is not limited to the above embodiment,
In the embodiment, the symbol forming portion formed by the first direct gate represents the side A or the side B of the tape. However, the symbol forming portion may be variously changed, for example, it may be a letter or numeral indicating a model or the like. is there.

[Effects of the Invention] As described in detail above, the present invention has excellent appearance and quality because the symbol forming portion is formed by the trace portion of the direct gate for the primary injection material so as to be provided on the outer surface of the case main body. Improvement can be achieved.

[Brief description of the drawings]

1 is a perspective view, FIG. 2 is a cross-sectional view of a mold, FIG. 3 is a cross-sectional view after performing primary molding, and FIG. 4 is a first direct view. FIG. 5 is a partially cutaway perspective view of a gate, and FIG. 5 is a plan view of a fixed mold plate. 4,8 ... symbol forming part 5,9 ... frame part 6 ... window part 33,33A ... first direct gate A ... primary injection material B ... secondary injection material

Claims (1)

(57) [Claims] A frame for accommodating a magnetic tape is provided on an outer surface of the frame.
In an audio cassette half molded with a primary injection material together with a symbol forming portion representing a surface and the like, and a tape-visible window provided in the frame portion is molded with a secondary injection material,
An audio cassette half, wherein the symbol forming portion is formed by a trace portion of the direct gate for the primary injection material.