JPH05298854A - Tape cassette and its production and molding die - Google Patents

Abstract

PURPOSE:To eliminate the problem of peeling and to widen the range for selection of resins by coating an intermediate resin layer having a low modulus of elasticity with resins on both sides, thereby forming cassette halves. CONSTITUTION:The first resin layer 4 is first formed by injecting an ABS resin and an elastomer is injected thereon to form the second resin layer 5 slightly smaller than the resin layer 4. Further, the ABS resin of the same quality as the quality of the resin layer 4 is injected to form the resin layer 6 slightly larger than the resin layer 5 to insert the resin layer 5 between the resin layers 4 and 6. The peripheral edge of the resin layer 6 is then welded to the resin layer 4, by which the cassette halves 2, 3 are formed in the form of coating the resin layer 5 with the resin layers 4, 6. The halves are then formed of at least the three resin layers 4, 5, 6 and the resin layer 5 is formed of the elastomer having the modulus of elasticity lower than the modulus of elasticity of the resin layers 4, 6 on both sides. The problem of the peeling of the resin layer 5 is then eliminated and the range for selecting the resins which can be used without the need for consideration of compatibility is widened. The tape cassette 1 having excellent vibration attenuation performance and rigidity is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette provided with rigidity and vibration damping by forming a cassette half with a multi-layered synthetic resin material, a method of manufacturing the same, and a molding die.

[0002]

2. Description of the Related Art In a magnetic recording tape cassette, for example, a compact tape cassette, the cassette half vibrates due to the vibration generated from the deck and the sound pressure generated from the speaker, which adversely affects the running of the magnetic tape and deteriorates the sound quality. ..

Therefore, as shown in FIG. 7, an inner layer 10 of a low elastic modulus synthetic resin is formed on the inner surface of an outer layer 101 of a high elastic modulus synthetic resin.
A tape cassette using a so-called two-layer cassette half 103 in which 2 is injection-molded and vibration is absorbed by the low elastic modulus synthetic resin inner layer 102 has also been developed.

[0004]

By the way, the above-mentioned conventional 2
The layered tape cassette has the following problems.

(1) In order to integrate the outer layer 101 and the inner layer 102 so that the outer layer 101 and the inner layer 102 are not easily separated from each other, the compatibility of the synthetic resins forming the outer layer 101 and the inner layer 102 must be taken into consideration. But for this,
The type of synthetic resin used for the outer and inner layers 101, 102 is limited.

(2) Due to the presence of the inner layer 102 of the low elastic modulus material, the mechanical strength, particularly the rigidity, of the cassette half is weakened.

The present invention has been made for the purpose of solving the above conventional problems.

[0008]

In the tape cassette of the present invention, at least three resin layers, that is, first, second and third resin layers, are provided, and the resin layer on both sides has an intermediate low elastic modulus resin. A cassette half was constructed of a resin material having a multi-layered structure covering the layers.

[0009]

[Function] Since the intermediate low-elastic-modulus resin layer is covered with the resin layers on both sides and the low-elastic-modulus resin layer is wrapped with the resin layers on both sides, the resin layers on both sides and the intermediate resin layer are compatible with each other. Even if it is not present, peeling of the intermediate resin layer can be prevented.

Further, since the surface of the intermediate low elastic modulus resin layer is covered with the elastic layer having a higher elastic modulus than this, the mechanical strength (rigidity) of the cassette half can be increased.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The tape cassette of the present invention, its manufacturing method, and a molding die used in the manufacturing method will be described below.

FIG. 1 is an exploded perspective view of a tape cassette 1 according to the present invention. The tape cassette 1 comprises upper and lower cassette halves 2 and 3.

The upper and lower cassette halves 2,
3 is formed of a resin material 7 having a three-layer structure including first, second and third resin layers 4, 5, 6.

The first and third resin layers 4 and 6 are made of ABS resin, and the second resin layer 5 is made of an elastomer having a lower elastic modulus than the first and third resin layers 4 and 6. ..

The cassette halves 2 and 3 are formed by covering the second resin layer 5 with the first and second resin layers 4 and 6 so as to sandwich it.

Next, a method of manufacturing the cassette halves 2 and 3 will be described.

The manufacture of the cassette halves 2 and 3 is shown in FIGS.
This is performed in the next step using the molding die 11 as shown in FIG.

First, as a first step, the first resin layer 4 is formed by injecting an ABS resin as shown in FIG.

Next, as a second step, as shown in FIG. 4, by injecting an elastomer onto the first resin layer 4, a second resin layer 5 slightly smaller than the first resin layer 4 is formed. Form.

Further, as a third step, as shown in FIG. 5, by injecting the same ABS resin as the first resin layer 4, the third resin layer 6 slightly larger than the second resin layer 5 is injected. And the second resin layer 5 is sandwiched between the third resin layer 6 and the first resin layer 4, and the peripheral portion of the third resin layer 6 is welded to the first resin layer 4. The cassette halves 2 and 3 are manufactured by covering the second resin layer 5 with these first and third resin layers 4 and 6.

Next, the molding die 11 will be described. The molding die 11 is slidably attached to a fixed die 12, a movable die 13 and either one of the fixed die 12 and the movable die 13 (the fixed die 12 in the embodiment). And a slide member (core) 14.

Then, as shown in FIG. 3, the fixed mold 1
2, the movable mold 13 and the slide member 14 form a cavity (space) for forming the first resin layer, and the ABS resin is injected into the cavity from the first resin injection port 21 for forming the first resin layer. As a result, the first resin layer 4 is formed.

After forming the first resin layer 4,
The slide member 14 is slid with respect to the fixed mold 12 by the slide member operating mechanism 15 described below, and
As shown in FIG. 5, a second resin layer 5 is formed by forming a cavity for forming the second resin layer and injecting an elastomer into the cavity from the second resin injection port 22 for forming the second resin layer. It is supposed to do.

After the second resin layer 5 is formed,
The slide member 14 is further slid to form a cavity for forming the third resin layer as shown in FIG. 5, and the third resin injection port 23 for forming the third resin layer is used to insert the first resin into the cavity. The third resin layer 6 is formed by injecting the same ABS resin as the layer 4.

The first resin injection port 21 is provided in the movable mold 13.

The first resin injection port 21 is provided with a first resin supply pipe 31 provided in the fixed mold 12, and a first plate for supporting the resin supply pipe which supports the tip of the first resin supply pipe 31. A second plate 34 having a resin flow path 33 connected to the first resin supply pipe 31 and one end surface of the second plate 34. Resin channel 33 of plate 34
Is connected to the first and third resin supply cylinders (not shown) through a third plate 36 having a resin flow path 35 connected to each other.

The second resin injection port 22 is provided in the slide member 14.

The second resin injection port 22 is the slide member 1
4 is provided on one end side of the second resin supply pipe 41 attached to No. 4, and the other end side of the second resin supply pipe 41 is slidably inserted into a pipe insertion hole 42 provided on the first plate 32. There is.

The second resin supply pipe 41 includes the first plate 32, the second plate 34, and the third plate 36.
Via the resin flow paths 43, 44 and 45 respectively provided in
It is connected to a second resin supply cylinder (not shown).

The third resin injection port 23 is also provided in the slide member 14 like the second resin injection port 22.

The third resin injection port 23 is a slide member 1.
The third resin supply pipe 51 attached to No. 4 is provided on one end side, and the other end side is slidably inserted into a pipe insertion hole 52 provided on the first plate 32.

The third resin supply pipe 51 includes the first plate 32, the second plate 34, and the third plate 36.
Via the resin flow paths 53, 54, 55 respectively provided in
It is connected to a third resin supply cylinder (not shown).

Resin flow paths 33, 5 of the third plate 36
4 are provided with first and second electromagnetic on-off valves 61 and 62, respectively. The first electromagnetic on-off valve 61 is opened, the second electromagnetic valve 62 is closed, and the first and third solenoids (not shown) are provided. If the molten resin is supplied from the resin supply cylinder, the molten resin will flow through the resin flow path 3
3, the first resin injection pipe 2 through the first resin supply pipe 31
1 is injected into the cavity.

Contrary to the above, the first electromagnetic on-off valve 6
1 is closed, the second solenoid on-off valve 62 is opened, and the first and second
When the molten resin is supplied from the resin supply cylinder, the molten resin passes through the resin flow path 54 and the third resin supply pipe 51 to form the third resin.
It is injected from the resin injection port 23 into the cavity.

Next, the slide member operating mechanism 15 will be described.

The slide member operating mechanism 15 is mounted on one side surface of the slide member 14 so as to face the first plate 32, and the spacer plate holding member 71 is attached.
And a spacer plate 72 slidably interposed between the spacer plate clasped body 71 and the first plate 32.

The spacer plate 72 is provided with three types of thick portions 73, a medium portion 74, and a thin portion 75. The thick portion 73, the medium portion 74, and the thin portion are provided. 75 are sandwiched between the spacer plate abutting portion 76 of the spacer plate sandwiching body 71 and the first plate 32, respectively.

When the thick portion 73 is sandwiched between the spacer plate abutting portion 76 of the spacer plate sandwiching body 71 and the first plate 32, the slide member as shown in FIG. 14, movable mold 13, fixed mold 1
2 forms a cavity for forming the first resin layer.

From the state of FIG. 3, the spacer plate 72 is located in the upper part of FIG.
When the inner wall portion 74 slides to the side of the spacer plate abutting portion 76 of the spacer plate holding body 71, the slide member 14 slides in the spacer plate. It moves between the spacer plate abutting portion 76 of the clasping body 71 and the first plate 32 until the medium thickness portion 74 is clasped to form a cavity for forming the second resin layer as shown in FIG. ..

From the state shown in FIG. 4, the spacer plate 72 is
4 further slides upward in FIG. 4, and the thin-walled portion 75 causes the spacer plate abutting portion 7 of the spacer plate holding body 71 to move.
When the slide member 14 is moved to the side of 6, the slide member 14 moves between the spacer plate abutting portion 76 of the spacer plate clasping body 71 and the first plate 32 until the thin portion 75 is clasped. As shown, a cavity for forming the third resin layer is formed.

Reference numeral 81 is a flow path volume adjusting mechanism provided in the second plate 34 for adjusting the volume of the resin flow path 43 of the first plate 32.
1 is a first block 8 which constitutes a part of the resin flow path 43.
2 and a second block 83 that restricts the movement of the second block 82.

Then, after the second resin layer 5 shown in FIG. 4 is injection-molded, when the slide member 14 moves and the residual molten resin is pushed back from the second resin supply pipe 41, the first resin The block 82 is slid to expand the volume of the resin flow path 43 so that the residual molten resin pushed back can be received.

All the driving operations of the resin molding die 11 such as the flow path volume adjusting mechanism 81 and the slide member driving mechanism 15 are automatically controlled by a controller (not shown).

The molding die 11 of the embodiment has the structure as described above, and in the state shown in FIG. 3, the first electromagnetic on-off valve 61 is open and the second electromagnetic on-off valve 62 is closed. The molten ABS resin of the first and third resin supply cylinders is injected into the cavity from the first resin injection port 21,
The resin layer 4 is formed.

When the first resin layer 4 is formed, the slide member operating mechanism 15 operates to move the slide member 14 to form a cavity for forming the second resin layer, and the elastomer of the second resin supply cylinder is The second resin layer 5 is formed by being injected into the cavity from the second resin injection port 22.

When the second resin layer 5 is formed, the second electromagnetic opening / closing valve 62 is opened, the first electromagnetic opening / closing valve 61 is closed,
The molten ABS resin of the first and third resin supply cylinders is injected into the cavity from the third resin injection port 23 to form the third resin layer 6.

When the second resin layer 5 is molded and then the third resin layer 6 is molded, the flow path volume adjusting mechanism 81 is used.
Operates to receive the elastomer pushed back from the second resin supply pipe 41 into the expanded resin flow path 43.

Then, the ABS formed as described above
The vibration damping property and rigidity of the three-layer cassette half consisting of resin / elastomer / ABS resin are compared with the conventional ABS resin single-layer cassette half and the ABS resin / elastomer two-layer cassette half. 6
The results as shown in (4) were obtained, and it was demonstrated that the cassette half having a two-layer structure is superior in both vibration damping property and rigidity.

In the embodiment shown in the drawing, the ABS resin is used for the first and third resin layers 4 and 6, and the elastomer is used for the second resin layer 5. GP-PS (general-purpose polystyrene), AS, and P are used for the layers 4 and 6.
A thermoplastic resin such as C is used, and HI- is used for the second resin layer 5.
You may use thermoplastics, such as PS, ABS, PP.

[0050]

The present invention has the following effects.

(1) In the tape cassette of the present invention, since the intermediate resin layer is covered with the resin layers on both sides (upper and lower) so that the intermediate resin layer is so-called wrapped, the problem of peeling is eliminated, and the resin layer mutual Since it is no longer necessary to consider the compatibility of the above, it is possible to widen the selection range of the resin that can be used, and it is possible to provide a tape cassette having more excellent vibration damping performance and rigidity.

(2) In the method of manufacturing the tape cassette of the present invention, the first resin layer is injection-molded, the second resin layer is then injection-molded on the first resin layer, and the third resin layer is further formed thereon. Since a cassette half having a multilayer structure is formed by repeating injection molding such as injection molding, a cassette half having a 4-layer or 5-layer structure can be easily formed as well as a 3-layer structure.

(3) In the molding die of the present invention, since the slide member is provided with the second and third resin injection ports, the slide member is slid into the cavity from the second and third resin injection ports. By injecting a molten resin, the second and third resin layers can be formed easily and easily.

[Brief description of drawings]

FIG. 1 is a partially cutaway exploded perspective view of a tape cassette of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is a sectional view showing a formation state of a first resin layer.

FIG. 4 is a cross-sectional view showing a formation state of a second resin layer.

FIG. 5 is a cross-sectional view showing a formation state of a third resin layer.

FIG. 6 is a characteristic diagram.

FIG. 7 is a perspective view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tape cassette 2, 3 ... Cassette half 4 ... 1st resin layer 5 ... 2nd resin layer 6 ... 3rd resin layer 7 ... 3 layer structure resin material 11 ... Molding die 12 ... Fixed die 13 ... Movable metal Mold 14 ... Sliding member 21 ... First resin injection port 22 ... Second resin injection port 23 ... Third resin injection port

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Claims (3)

[Claims] 1. At least three of the first, second and third resin layers
A tape cassette comprising two resin layers, wherein a cassette half is formed of a resin material having a multi-layer structure in which resin layers on both sides are coated with an intermediate resin layer having a low elastic modulus. 2. The first resin layer is injection-molded and then the first resin layer is formed.
A second resin layer is injection-molded on the resin layer, a third resin layer is further injection-molded on the second resin layer, and the second resin layer is covered with the first resin layer and the third resin layer. A method for manufacturing a tape cassette, comprising: 3. A fixed mold, a movable mold, and a slide member provided on one of the fixed mold and the movable mold, the slide being carried out after injection molding a first resin layer. A molding die in which a member is slid to injection-mold a second resin layer, the second resin layer is injection-molded, and then the slide member is slid to injection-mold a third resin layer. The slide member is provided with a resin injection port for forming a second resin layer for injection molding the second resin layer and a resin injection port for forming a third resin layer for injection molding the third resin layer. Molding die characterized by that.