JPH0963235A - Tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate a projecting pin for a fixed guide pin by improving the releasing property of the fixed guide pin at the time of taking out the low shell from a metallic mold after molded. SOLUTION: In this tape cassette, the fixed guide pin 18 is projectingly formed on the lower shell 3 integrally therewith. The fixed guide pin 18 is formed to the deformed columnar shape, the diameters of which are gradually made smaller as it goes from the base part having elliptic cross-sectional shape toward the tip part having complete round cross-sectional shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette used for recording and reproduction, and particularly to the shape of a fixed guide pin provided in a tape running path.

[0002]

2. Description of the Related Art First, an example of a conventional tape cassette will be described with reference to FIGS.

The tape cassette illustrated here is a so-called audio compact cassette, and in the figure, reference numeral 1 indicates the cassette housing, which is formed by a styrene resin material in a substantially symmetrical shape. The shell (cover half) 2 and the lower shell (base half) 3 are combined and fixed by screwing.

Hub drive shaft insertion holes 9 and 10 are formed in two positions on the left and right sides of both shells 2 and 3, and the inside of the cassette housing 1 is associated with the hub drive shaft insertion holes 9 and 10. A pair of left and right hubs 12 around which a tape (magnetic tape) 11 is wound are rotatably housed. Both ends of the tape 11 wound around the hub 12 are clampers 1 respectively.
It is fixed to the hub 12 by 2a.

A tape 11 is provided on the front surface of the cassette housing 1.
An opening 13 through which the tape 11 is exposed, that is, the tape 11 drawn out from the hub 12 on one side is
A tape running path is formed so that the tape running path can be wound around the hub 12 on the other side.

Inside the cassette housing 1, the lower shell 3
On the inner surface side of the above, shaft columns 16 are symmetrically provided upright on both left and right sides of the opening 13, and a rotation guide roller 17 is rotatably supported by the shaft columns 16. Further, on the inner surface side of the lower shell 3, a cylindrical fixed guide pin 18 located between the rotation guide roller 17 and the hub 12 is erected symmetrically, and the tape 11 drawn out from the hub 12 is By being guided by the fixed guide pin 18 and the rotation guide roller 17, the tape travels along a predetermined tape traveling path.

Further, in the inside of the cassette housing 1,
Between the upper shell 2 and the hub 12, and between the lower shell 3 and the hub 1.
For the purpose of stabilizing the running property of the tape and preventing winding disorder, liner sheets 21 and 22 made of a thin sliding sheet material such as PET are arranged so as to sandwich the hub 12 from above and below.

The central portion of the opening 13 through which the tape 11 is exposed serves as a head insertion portion 13a into which the magnetic head of the cassette tape recorder is inserted, and the inserted magnetic field is inserted in the back of the head insertion portion 13a. Leaf spring 24 having a pressure bonding pad 23 made of felt for pressure bonding the tape 11 to the head mounted in the center, and the hub 1
A metal shield plate 25 for magnetically isolating the tape 11 wound around the tape 2 from the magnetic head is incorporated.

In the tape cassette constructed as described above, when the fixed guide pin 18 is viewed, the fixed guide pin 18 is formed in a simple columnar shape as shown in FIG.

The fixed guide pin 18 is formed integrally with the lower shell 3 by injection molding. However, since it protrudes more than the main body of the lower shell 3, the fixed guide pin 18 has a deeply engraved molding space. I need.

FIG. 17 shows a sectional structure of a portion for molding a fixed guide pin in a lower shell molding die.
In the figure, 101 is a fixed side mold, and 102 is a movable side mold. By injection-filling a resin material into a molding space (cavity) formed between the fixed side mold 101 and the movable side mold 102, Fixed guide pin 18 integrally with the lower shell 3
Is molded.

[0012]

In this molding, the resin injected and filled in the mold is shrunk during the cooling and solidification process. In the case of the lower shell 3, contraction occurs such that the size of the lower shell 3 shrinks toward its center, and therefore a force acts in the direction in which the resin is fixed to the mold.

At this time, since the fixed guide pin 18 has a simple cylindrical shape, it has a large force to bite into the mold, and the releasability when the lower shell 3 is taken out from the mold is poor. For this reason,
In the mold, as shown in FIG. 17, it was necessary to provide a protruding pin 103 for protruding the fixed guide pin 18.

Providing the ejection pin dedicated to the fixed guide pin in the die in this way not only complicates the die structure by that much, but the ejection pin slides in the die to make this sliding movement. There was a problem that burrs were generated on the fixed guide pin at the time of molding because the mold was worn at the part. The present invention has been made in view of such problems.

[0015]

SUMMARY OF THE INVENTION In order to solve the above problems, according to the present invention, a pair of hubs around which tapes are wound are rotatably housed in a cassette housing, and a tape between the pair of hubs is rotatably provided. In a tape cassette having a fixed guide pin for guiding the tape in the running path, the fixed guide pin has a shape in which the diameter gradually decreases from the base of the elliptical cross-sectional shape toward the tip of the true circular cross-sectional shape. It is formed by. By forming the fixed guide pin in such a shape, the mold releasability at the time of taking out from the mold is improved, and it is not necessary to provide the mold with a protrusion pin dedicated to the fixed guide pin.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The tape cassette illustrated here is a so-called compact cassette for audio, similar to the above-mentioned conventional example. In the figure, reference numeral 1 shows the cassette housing of the tape cassette of this embodiment, and this cassette housing 1 is styrene. An upper shell (cover half) 2 and a lower shell (base half) 3 which are molded in a substantially symmetrical shape with a resin material are combined and fixed by ultrasonic welding.

As shown in FIG. 4A, concave holes 4 are provided at the four corners on the inner surface side of the upper shell 2, and correspondingly, at the four corners on the inner surface side of the lower shell 3, as shown in FIG. 4B. A convex pillar 5 is provided. A concave hole 7 is also provided in the central portion on the inner surface side of the upper shell 2, and correspondingly, a convex column 8 is also provided in the central portion on the inner surface side of the lower shell 3.

When the upper shell 2 and the lower shell 3 are assembled, the convex columns 5 and 8 are inserted and fitted into the concave holes 4 and 7 so that the shells 2 and 3 are aligned with each other and the fitting is performed. At the joint, both shells 2 and 3 are heat-welded by ultrasonic waves.

Hub drive shaft insertion holes 9 and 10 are formed in two positions on the left and right sides of both shells 2 and 3, and the inside of the cassette housing 1 corresponds to the hub drive shaft insertion holes 9 and 10. A pair of left and right hubs 12 around which a tape (magnetic tape) 11 is wound are rotatably housed. Both ends of the tape 11 wound around the hub 12 are clampers 1 respectively.
It is fixed to the hub 12 by 2a.

A tape 11 is provided on the front surface of the cassette housing 1.
Is provided, that is, the tape running path is formed so that the tape 11 drawn from the hub 12 on one side is wound around the hub 12 on the other side through the opening 13. .

The front portion of the cassette housing 1 which constitutes the opening 13 is formed as trapezoidal bulging portions 14 and 15 in which parts of both shells 2 and 3 are bulged in the cassette thickness direction. The inner surface sides of the shells 2 and 3 corresponding to the bulging portions 14 and 15 are concave portions 14a and 15a that are recessed following the bulging shapes of the bulging portions 14 and 15, respectively.

Inside the cassette housing 1, the lower shell 3
On the inner surface side of the above, shaft columns 16 are symmetrically provided upright on both left and right sides of the opening 13, and a rotation guide roller 17 is rotatably supported by the shaft columns 16. Further, on the inner surface side of the lower shell 3, a cylindrical fixed guide pin 18 located between the rotation guide roller 17 and the hub 12 is erected symmetrically, and the tape 11 drawn out from the hub 12 is By being guided by the fixed guide pin 18 and the rotation guide roller 17, the tape travels along a predetermined tape traveling path.

Here, as shown in FIG. 3, the fixed guide pin 18 is defined by the maximum practical winding diameter of the tape 11 wound around the hub 12 (regulation of hub diameter according to IEC standard (diameter 21 mm or more), etc. and MIAJ standard). The practical maximum tape winding diameter required in consideration of the thickness and length of the tape and the space inside the cassette housing, diameter about 53 mm) 1
1A and the inner surface (tape guide surface) of the rotation guide roller 17 inside the cassette with respect to the common outer tangent line a that contacts the
Further, it is provided at a position in contact with this common outer tangent line a.
As a result, in the tape cassette of this example, the winding angle of the tape 11 with respect to the fixed guide pin 18 is minimized,
The tape 11 is designed to run with less sliding resistance.

Further, guide ribs 19 and 20 for regulating the width direction of the tape are provided on the inner surfaces of the upper shell 2 and the lower shell 3 so as to vertically oppose each other. These guide ribs 19 and 2
0 is symmetrically provided so as to be located between the fixed guide pin 18 and the rotating guide roller 17 and in the vicinity of the fixed guide pin 18, and as shown in FIG. By restricting the upper and lower edge portions of the tape 11, the tape 11 is suppressed from fluctuation (blurring) in the width direction and wound around the hub 12 in a uniform winding shape.

Furthermore, inside the cassette housing 1,
As shown in FIG. 2, between the upper shell 2 and the hub 12, and between the lower shell 3 and the hub 12, for the purpose of stabilizing the running property of the tape and preventing winding disorder, thin lubricity such as PET is used. The liner sheets 21 and 22 made of sheet material are the hub
Are arranged so as to be sandwiched from above and below (the liner sheets 21 and 22 are not shown in FIG. 1).

The central portion of the opening 13 through which the tape 11 is exposed serves as a head insertion portion 13a into which the magnetic head of the cassette tape recorder is inserted, and the inserted magnetic field is inserted in the back of the head insertion portion 13a. A leaf spring 24 in which a felt pressure pad 23 for pressure-bonding the tape 11 to the head is attached to the central portion, and the hub 1
A metal shield plate 25 for magnetically isolating the tape 11 wound around the tape 2 from the magnetic head is incorporated.

In the tape cassette of the present example constructed as described above, the concave hole 7 and the convex column 8 in the central portion of the cassette housing 1 are provided.
The structure of the fitting portion will be described in more detail.

As shown in FIG. 5, a cylindrical receiving portion 6 is provided on the inner surface side of the upper shell 2, and correspondingly, a concave hole of the receiving portion 6 is provided on the inner surface side of the lower shell 3. A convex column 8 having an outer diameter dimension substantially equal to the inner diameter of 7 is provided. still,
The receiving portion 6 and the convex column 8 are formed by the upper shell 2 and the lower shell 3, respectively.
Are provided in the concave portions 14a and 15a on the inner surface side.

When the upper shell 2 and the lower shell 3 are combined, as shown in FIG. 7, the convex column 8 on the lower shell 3 side is inserted into the concave hole 7 of the receiving portion 6 on the upper shell 2 side in a close-fitting manner. By fitting, both shells 2 and 3 are correctly combined.

To assemble the tape cassette, first, the tape 11 and other parts are all assembled in the lower shell 3,
After that, the upper shell 2 is put on the lower shell 3 to be assembled, but in the tape cassette of this example, the tape 11 is sandwiched between the receiving portion 6 of the upper shell 2 and the lower shell 3 during this assembly. A plurality of pinch prevention projections 27 are provided around the convex column 8 to prevent them from being caught.

In the present embodiment, the pinch prevention projections 27 are formed continuously on the peripheral surface of the convex column 8, and there are one location corresponding to the central portion of the cassette housing and two locations corresponding to the left and right hubs 12, respectively. Are provided at three locations. The distance between the three pinch prevention projections 27 is preferably about 30 ° to 75 °. In this example, as shown in FIG. 6, the three pinch prevention projections 27 are provided at intervals of 60 °.

Further, as shown in FIG. 7, the entrapment preventing projection 27 does not interfere with the receiving portion 6 when the upper shell 2 and the lower shell 3 are combined, and the concave portion 15 is formed.
It is necessary to form the height dimension such that the protruding amount b from the inner surface of the lower shell 3 excluding a is at least 1 mm or more.

Further, the convex column 8 of the pinch prevention projection 27
It is necessary that the amount of protrusion from the outer diameter of the receiving portion 6 is equal to or larger than the outer diameter of the receiving portion 6. In this example, as shown in FIG. The pinch prevention protrusion 27 is formed by.

As described above, in the tape cassette of this embodiment, since the pinch prevention projections 27 are provided around the convex column 8, the upper shell 2 is assembled in the tape cassette assembling process.
Even if the tape 11 wound around the hub 12 is loosened before the lower shell 3 is covered with the lower shell 3, the loosened tape does not project to the convex column 8 because of the pinch prevention projection 27.

Therefore, when the upper shell 2 is put on the lower shell 3 to be assembled, the tape 11 is not caught between the receiving portion 6 of the upper shell 2 and the lower shell 3.

Although the pinch prevention projection 27 is formed continuously with the convex column 8 in this example, it may have a pin shape or a wall shape independent of the convex column 8. Further, the entrapment prevention protrusions 27 are not limited to three places, and may be provided in two places or four places or more.

8 to 10 show the shape of the fixed guide pin 18 in the tape cassette of this example.

The fixed guide pin 18 is formed integrally with the lower shell 3 in a projecting manner. The shape of the fixed guide pin 18 is, as shown in the enlarged view of FIG. It is formed in a cylindrical shape.

FIG. 9A shows the sectional shape of the base of the fixed guide pin 18, and FIG. 9B shows the sectional shape of the tip end.
As is clear from this, the fixed guide pin 18 has a columnar shape in which the diameter gradually decreases from the base of the elliptical (oval) cross-sectional shape to the tip of the true circular cross-section.

In this case, the fixed guide pin 18 is formed so that the tape-sliding surface 18a is perpendicular to the lower shell 3, that is, the tape-sliding surface 18a is not inclined so that the tape travels. It has a shape that does not impair the running performance.

FIG. 10 shows a sectional structure of a portion for molding the fixed guide pin in the lower shell molding die.
In the figure, 101 is a fixed side mold, and 102 is a movable side mold. By injection-filling a resin material into a molding space (cavity) formed between the fixed side mold 101 and the movable side mold 102, Fixed guide pin 18 integrally with the lower shell 3
Is molded.

In this molding, the resin injected and filled into the mold is shrunk during the cooling and solidification process, and in the case of this example, the lower shell 3 is shrunk so that its size is reduced toward the center thereof. Therefore, a force acts in the direction in which the resin is fixed to the mold.

Most of the fixed guide pins 18 except the sliding surface 18a of the tape are inclined with respect to the direction of the force for fixing the tape to the mold. It acts as a so-called draft of time.

Therefore, when the molded lower shell 3 is taken out from the mold, the mold releasability is good. Therefore, the lower shell 3 can be easily removed without providing a protruding pin for a fixed guide pin in the mold. It can be removed from the mold.

11 to 13 show the structure of the vicinity of the fixed guide pin 18 in the tape cassette of this example.

That is, in the tape cassette of this embodiment, the tape wound around the hub is prevented from entering between the side wall 1a of the cassette housing 1 and the fixed guide pin 18 and being wound therein. The prevention wall 28 is provided near the fixed guide pin 18 and outside the tape running path.

The entanglement prevention wall 28 is formed so as to extend from the side wall on the inner surface side of the shell on the side where the fixed guide pin 18 is not provided, that is, the upper shell 2 in the present embodiment, and to project from the upper shell 2 and the lower shell 2. With the shell 3 combined,
The fixed guide pin 18 is structured so as to be spaced from the fixed guide pin 18 so as not to interfere with normal tape running.

In this embodiment, the formation position of the roll-up prevention wall 28 coincides with the position of the guide rib 19 for regulating the width direction of the tape, that is, the roll-up prevention wall 28 is formed so as to be continuous with the guide rib 19. .

The wrap-up prevention wall 28 needs to be formed to have a height dimension that covers at least one-half or more of the width of the tape 11, and in this example, covers substantially the entire width of the tape 11 and has an upper shell. The height dimension is such that a slight gap remains between the guide rib 20 of the lower shell 3 in a state where the lower shell 3 and the lower shell 3 are combined.

At the tip of the entanglement prevention wall 28, a chamfered inclined surface 28 is formed at the inner corner corresponding to the tape 11.
a is formed. This is to prevent the tape 11 from being damaged when the upper shell 2 is covered with the lower shell 3, and the inclination angle thereof is about 30 ° with respect to the tape facing surface of the entanglement prevention wall 28.

Further, at the tip of the entanglement prevention wall 28,
A chamfered inclined surface 28b is also formed at the outer corner portion. This inclined surface is a surface that serves as a guide when the upper shell 2 is put on the lower shell 3.

As described above, in the tape cassette of this example,
By providing the winding prevention wall 28 between the side wall 1a of the cassette housing 1 and the fixed guide pin 18, when the tape is loosened as shown in FIG. 13, the winding prevention wall 28 regulates the tape 11. Therefore, the tape 11a that is wound around the hub and is slack is attached to the side wall 1 of the cassette housing 1.
It does not enter between the a and the fixed guide pin 18 and get caught.

Further, in this example, the fixed guide pin 18
Since the wrap-around prevention wall 28 is provided on the shell on the side where the tape 11 is not provided, that is, on the upper shell 2 side, the workability when the tape 11 is incorporated is not adversely affected. That is,
When assembling a normal tape cassette, the tape 11
Is attached to the lower shell 3 provided with the fixed guide pin 18, so that the entanglement prevention wall 28 is provided on the upper shell 2 side.
The inclusion prevention wall 28
The tape 11 can be incorporated into the lower shell 3 without disturbing.

In this example, the entrainment prevention wall 28 is continuous with the guide rib 19 provided on the inner surface side of the upper shell 2.
Therefore, the moldability is good. That is,
Since the entanglement prevention wall 28 is a structure that protrudes more than the main body portion of the upper shell 2, it is difficult to release the mold from the mold after molding, and it is difficult to sufficiently fill the resin during molding. However, since the entanglement prevention wall 28 of the present example is formed continuously with the guide rib 19, the shape thereof is a stepwise protruding shape, so that the above adverse effect on the formability is unlikely to occur. Good moldability can be obtained.

Further, since the chamfered inclined surface 28a is formed at the tip corner portion of the entanglement prevention wall 28,
In assembling the tape cassette, the tape 11 is not damaged when the upper shell 2 is covered with the lower shell 3. That is, even when the tape 11 is slightly loosened when the upper shell 2 is covered with the lower shell 3, the tape 11 can be escaped by the inclined surface 28a, so that the tape 11 can be removed between the entanglement prevention wall 28 and the lower shell 3. It will not be pinched, and therefore will not damage the tape 11.

In this example, the roll-in prevention wall 28 is shown as the roll-in prevention part, but it may be replaced with a pin-shaped projection.

In the above-described embodiments, the audio compact cassette has been described, but it goes without saying that the present invention is not limited to this audio compact cassette.

[0059]

According to the present invention, since it is not necessary to provide the protruding pin for the fixed guide pin in the mold, the structure of the mold can be simplified and the reliability of the mold can be improved. . Further, since the protruding pin for the fixed guide pin in the mold is eliminated, it is possible to prevent the fixed guide pin from being burred.

[Brief description of drawings]

FIG. 1 is a plan view showing an upper shell of a tape cassette of an embodiment by cutting it.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is an explanatory diagram of positions of fixed guide pins.

FIG. 4A is a plan view seen from the inner surface side of the upper shell, and FIG. 4B is a plan view seen from the inner surface side of the lower shell.

5A is a perspective view showing a receiving portion on the upper shell side, and FIG. 5B is a perspective view showing a convex column portion on the lower shell side.

FIG. 6 is an explanatory diagram of a pinch prevention protrusion.

FIG. 7 is a cross-sectional view of a fitting portion of a concave hole on the upper shell side and a convex column on the lower shell side, (A) shows a state before the upper shell and the lower shell are combined, and (B) shows a combined state. It is in a state.

FIG. 8 is an enlarged perspective view showing a portion of a fixed guide pin of the lower shell.

FIG. 9 is a view showing a cross-sectional shape of a fixed guide pin, (A)
Is a base, and (B) is a cross section of the tip.

FIG. 10 is a cross-sectional view of a lower shell molding die.

FIG. 11 is an enlarged perspective view showing a portion of a roll-up prevention wall of the upper shell.

FIG. 12 is a cross-sectional view of a portion of a roll-in prevention wall.

FIG. 13 is an explanatory diagram of an effect of the entanglement prevention wall.

FIG. 14 is a perspective view showing an upper shell of a conventional tape cassette by cutting it.

FIG. 15 is an exploded perspective view of the same.

FIG. 16 is an enlarged perspective view showing a portion of a fixed guide pin of the lower shell.

FIG. 17 is a cross-sectional view of a lower shell molding die.

[Explanation of symbols]

 1 Cassette Housing 2 Upper Shell 3 Lower Shell 11 Tape 12 Hub 18 Fixed Guide Pin 18a Tape Sliding Surface

Claims (2)

[Claims] 1. A pair of hubs around which a tape is wound are rotatably housed inside a cassette housing, and a fixed guide pin for guiding the tape is provided in a tape running path between the pair of hubs. In the tape cassette, the fixed guide pin is formed in a shape in which the diameter gradually decreases from the base of the elliptical cross-sectional shape toward the tip of the true circular cross-section. 2. The tape cassette according to claim 1, wherein the fixed guide pin is formed such that a surface of the fixed guide pin which comes into sliding contact with the tape is perpendicular to the cassette housing.