JPH11306717A - Magnetic tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the low-cost manufacturing of a slider spring for urging forwards a slider of a magnetic tape cassette as a coil spring, eliminate the need for the accurate positioning in a spring assembling step to make a sample and low-cost assembling head usable in the automated assembling and the assembling mechanism and assembling work easy. SOLUTION: A spring for urging a slide 14 of the magnetic tape cassette is a coil spring 26 having a coil 26a at the center and arm having a laterally symmetric length, and on the occasion of assembling, the center coil 26a is mounted in a recess of a coupling of an intermediate wall 12f provided at a lower half 12. A bend 26c parallel to the coil 26a is pref. provided at the top end of the arm of the twisted coil spring 26.

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, and more particularly to a magnetic tape cassette provided with a slider slidably provided on a lower half for protecting a magnetic tape housed in a cassette case.

[0002]

2. Description of the Related Art As is well known, a magnetic tape cassette is
Fix both ends of the long magnetic tape to a pair of winding hubs and wind the magnetic tape from both ends to each winding hub,
A pair of take-up hubs around which the magnetic tape is wound are rotatably housed in a cassette case, and the magnetic tape between the pair of take-up hubs is stretched through a predetermined path to form a tape deck or the like. A magnetic tape at a position corresponding to a magnetic head of a recording / reproducing apparatus (hereinafter, referred to as a recording / reproducing apparatus) is protruded, and only the magnetic tape at the protruding portion can be exposed to the outside.

[0003] In order to prevent the fingers from coming into contact with the magnetic layer surface of the magnetic tape and to prevent dust from adhering to the overhanging portion of the magnetic tape that can be exposed from the cassette case.
A front lid is provided in the upper half, which swings between a closed position for covering the magnetic tape and an open position for exposing the magnetic tape, and is spring-biased toward the closed position. Further, below the overhanging portion of the magnetic tape, an opening is provided for inserting a tape loading device of the recording / reproducing device when the magnetic tape cassette is loaded in the recording / reproducing device so that the magnetic tape abuts on the magnetic head. Is provided on the lower front side of the lower half, and a slider for closing this opening is provided on the bottom surface of the lower half so as to be slidable in the front-rear direction from the outside. The slider is provided on the bottom surface of the lower half. The provided reel shaft insertion hole can also be opened and closed at the same time, and the slider is always spring-biased in a direction (frontward) to close the cassette opening and the reel shaft insertion hole.

When such a magnetic tape cassette is loaded into the recording / reproducing apparatus, the slider slides backward and the front cover moves to the open position in conjunction with the operation of loading the magnetic tape cassette into the recording / reproducing apparatus. Then, the overhanging portion of the magnetic tape is brought into contact with the magnetic head by the tape loading device of the recording / reproducing device, and the magnetic tape is arranged at a position where recording or reproduction is possible. Then, the reel shaft of the recording / reproducing apparatus inserted into the take-up hub from the bottom rotates and takes up the magnetic tape on one take-up hub, so that the magnetic tape fed from the other take-up hub is applied to the magnetic head. It moves in contact with it and records information on a magnetic tape or reproduces information from the magnetic tape.

Hereinafter, a conventional magnetic tape cassette will be described with reference to FIG. FIG. 4 is an exploded perspective view showing a schematic configuration of an example of a conventional magnetic tape cassette. As shown in the figure, the magnetic tape cassette has a pair of winding hubs 116,
The magnetic tape 118 is wound around each of the winding hubs 116 and 116 from both ends while being fixed to the magnetic tape 118, and the pair of winding hubs 116 and 116 around which the magnetic tape 118 is wound are rotatably connected to the upper half 110 and the lower half 110. The magnetic tape 112 is housed in a cassette case connected in a lid-to-lid manner, and a magnetic tape 118 between the pair of winding hubs 116 is stretched through a predetermined path. Overhang portion 118a of the magnetic tape corresponding to the position
It is configured such that only the outside can be exposed.

In order to protect the magnetic layer surface of the magnetic tape 118a at the projecting portion that can be exposed from the cassette case, a front cover 124 supported by pins 124a is provided on the upper half 110 with the magnetic tape 11 at the projecting portion.
It is provided so as to swing between a closed position for covering 8a and an open position for exposing.

The lower half 112 has a rectangular bottom surface 112a, and a pair of winding hubs 116, 116 around which a magnetic tape 118 is wound, is provided on the bottom surface 112a.
Is rotatably supported, and when a magnetic tape cassette is loaded into the recording / reproducing apparatus, a reel shaft (not shown) is inserted from the recording / reproducing apparatus into the take-up hub 116, and
16 for rotating and driving the reel 16
12b. Further, the bottom surface 112a has overhangs 112c, 112c extending forward from both left and right ends, and the left and right overhangs 112c, 112c are stretched between a pair of winding hubs 116, 116. Magnetic tape 11
The tape guides 112d, 112d, which guide the tape 8 through a predetermined path to the front of the cassette case, have bottom tapes 112d.
It stands upright from a. The left and right overhang portions 112
The space between c and 112c is a space without the bottom surface 112a of the lower half 112, and forms an opening of the cassette case. The opening of the cassette case is a space into which a tape loading device (not shown) provided in the recording / reproducing apparatus enters when a magnetic tape cassette is loaded in the recording / reproducing apparatus.

The slider 114 has a thin flat bottom surface 114a provided in contact with the bottom surface 112a of the lower half 112 from below.
12 for closing the opening of the cassette case and the reel shaft insertion holes 112b, 112b provided for preventing dust, and is guided by the side wall 112e of the lower half 112 to slide forward and backward and move forward. As a result, the opening of the cassette case and the reel shaft insertion hole 112b, 1
12b is closed and opened by moving backward. On the bottom surface 112a of the lower half 112, an intermediate wall 112g that is curved in a C shape along the magnetic tape 118 wound around the winding hub 116 is provided upright. , The torsion coil spring 12 fitted to the pin 112f erected from the bottom surface 112a
The slider spring 6 is urged forward (in the direction in which the slider 114 closes) by pressing a spring receiving rib 114c provided at the front center of the slider 114. Here, the coil portion 126 of the torsion coil spring 126
a is fitted to the pin 112f of the lower half 112, the short arm 126b is supported by the intermediate wall 112g, and the long arm 126c presses the spring receiving rib 114c of the slider 114.

Therefore, when the magnetic tape cassette is not used, the slider 114 is urged forward by the coil spring 126 functioning as a torsion coil spring, and the space between the left and right overhanging portions 112c of the lower half 112 (see FIG. 1). The opening) and the reel shaft insertion hole 112b are closed by the bottom surface 114a of the slider 114. When the magnetic tape cassette is loaded in the recording / reproducing apparatus, the slider 1
Reference numeral 14 denotes a slider 114 according to the operation of the recording / reproducing apparatus.
The ribs 114d, 114d provided on the front surface of the lower half 112 are automatically moved backward by being pressed, and the opening between the left and right overhanging portions 112c, 112c of the lower half 112 is opened, so that the tape loading of the recording / reproducing apparatus is performed. Device can be inserted,
The positions of the reel shaft insertion holes 112b, 112b of the lower half 112 and the reel shaft insertion holes 114b, 114b of the slider 114 match, so that the reel shaft of the recording / reproducing apparatus can be inserted.

In the conventional magnetic tape cassette, as shown in FIG. 4, a torsion coil spring 126 is used as a slider spring for urging the slider 114. This torsion coil spring 126 is provided on one side of the lower half 112. Slider 1
14 was sometimes unstable. Therefore, a slider spring using a leaf spring has been known.

FIG. 5 is an exploded perspective view of a lower half 130 and a slider 134 of a conventional magnetic tape cassette using a leaf spring. The lower half 130 has a C-shaped intermediate wall 130 provided vertically on a bottom surface 130a of the lower half 130 along a magnetic tape (not shown) wound around a take-up hub.
b. On the upper side of the intermediate wall 130b, a substantially triangular plate portion 130c is provided so as to cover from above, and a columnar rib 130d is provided downward from the triangular plate portion 130c. I have. Below the portion surrounded by the intermediate wall 130b and the triangular plate portion 130c, there is no bottom surface 130a of the lower half 130, which is open, and bends an elongated rectangular steel as shown in FIG. The leaf spring 132 can be mounted from below.

On the other hand, the slider 134 has a bottom surface 134a.
A rib 134b is provided in a vertical direction, and a front surface of the spring receiving rib 134b faces a back surface of the magnetic tape at a portion stretched between a pair of winding hubs (not shown). The rear surface of the rib 134 b is
32a comes into contact. The cage rib 134b receives the urging force of the leaf spring 132, protects the magnetic tape, and has a continuous shape to prevent dust in the cassette. Further, the bottom surface 1 of the slider 134
When the slider 134 is mounted on the lower half 130, the leaf spring 13a incorporated into the lower half 130 from below is provided.
2 is held from below. In addition, this leaf spring 132
SUS631 precipitation hardened steel or the like is preferable as the material,
The Vickers hardness (Hv) is preferably 540 or more.

[0013]

However, like the conventional magnetic tape cassette shown in FIG.
In the case where the slider spring for urging the slider 4 is constituted by the torsion coil spring 126 and this torsion coil spring 126 is incorporated into the combined lower half 112 and slider 114,
Lower the coil portion 126a of the coil spring 126 into the lower half 11
It is necessary that the short arm 126b and the long arm 126c of the coil spring 126 be connected to the spring receiving rib 114c of the slider 114 and the intermediate wall 112 of the lower half 112, respectively.
In order to insert the gap between them, the gap needs to be incorporated in a state in which the gap is reduced against the urging force, and there is a problem that high accuracy is required for the assembling work. Further, when the torsion coil spring 126 is incorporated from above, it is necessary to cut off a part of the triangular plate portion 112h provided above the intermediate wall 112g in order to support the short arm 126b with the intermediate wall 112g.

Further, as in a magnetic tape cassette shown in FIG. 5, a leaf spring 132 is used as a slider spring for urging the slider.
When using the plate spring 132 for biasing the slider 134 into the lower half 130 from below,
Normally, the lower half 130 flows upward on the line by an automatic machine as shown in FIG.
In order to increase the number of processes for turning over the plate spring or to provide a unit for incorporating the leaf spring 132 from below, the assembling work becomes complicated, the mechanism used for assembling becomes extremely complicated, and the assembling cost increases. there were. Further, the leaf spring 132 used as the slider spring is more expensive than the above-mentioned torsion coil bob, and is made of stainless steel S in order to stably secure a sufficient stroke amount.
US631 is used, and a precipitation hardening heat treatment or the like is additionally performed.

The present applicant has filed a Japanese patent application No. Hei 10-9107.
In the specification, when a leaf spring is used as the slider spring,
There has been proposed a magnetic tape cassette in which a slider biasing leaf spring can be incorporated from above into a lower half assembled with a slider. In this magnetic tape cassette, the leaf spring can be incorporated from above the lower half, so that the assembling work and the assembling mechanism can be simplified as compared with the magnetic tape cassette shown in FIG. However,
Since the boss (rib) for holding the central portion of the leaf spring is provided upright from the bottom surface of the lower half in the center concave portion of the intermediate wall of the lower half, in the assembly process of the slider biasing leaf spring, Then, the leaf spring is deformed so as to expand the spring while holding it, and the center of this deformed leaf spring is inserted into the narrow gap between the center recess of the intermediate wall and the leaf spring mounting rib, and then the spring is returned to its original shape. When performing automatic assembly, a considerably large precision and expensive assembly head had to be used.

The present invention has been made in view of these problems of the prior art, and enables a slider spring for biasing a slider to be produced as a torsion coil spring at a low cost, and the coil portion of the torsion coil spring is lowered. Eliminates the need to fit the pins erected on the halves, eliminates the need for accurate positioning in the spring assembly process, and allows a simple and inexpensive assembly head to be used in automatic assembly. It is an object of the present invention to provide a magnetic tape cassette that can make the assembling work easier than when using a conventional torsion coil spring.

[0017]

In order to solve these problems, according to the present invention, both ends of a long magnetic tape are wound and fixed on a pair of winding hubs, and the magnetic tape is wound. The pair of winding hubs are rotatably housed in a cassette case, the magnetic tape between the pair of winding hubs is stretched through a predetermined path, and the magnetic tape at a position corresponding to a magnetic head. Only a magnetic tape cassette configured to be exposed to the outside, comprising an upper half and a lower half, a cassette case for rotatably storing the pair of winding hubs, and a lower half of the cassette case. The lower half is slidably mounted in the front-rear direction along the bottom surface, and covers the front lower opening of the lower half and the reel shaft insertion hole on the bottom surface so as to be openable and closable from the outside of the bottom surface. Who close And a spring for urging the slider, wherein the spring for urging the slider is a torsion coil spring having a coil portion in the center and arms on both sides, The half faces the opening, and an intermediate wall having a concave portion that supports the coil surface of the coil portion of the torsion coil spring is provided upright from the bottom surface at the center, and the bottom surface is a bottom portion of the coil portion of the torsion coil spring. A spring receiving rib extending from the bottom of the torsion coil spring to support the distal ends of the two arm portions of the torsion coil spring. Provided is a magnetic tape cassette which is provided upright.

The two arms of the torsion coil spring have substantially the same length on both sides, and the distal end of the arm is connected to the coil portion which abuts the spring receiving rib of the slider. Preferably, a parallel bend is provided. Further, it is preferable that storage walls are provided on both sides of the concave portion at the center of the intermediate wall of the lower half on which the torsion coil spring is mounted, the storage walls being loosely engaged with the coil portion of the torsion coil spring.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic tape cassette of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings. FIG. 1 is an exploded perspective view showing a schematic configuration of an embodiment of a magnetic tape cassette according to the present invention, and FIG. 2 is a lower half showing details of an attached state of a torsion coil spring for urging a slider forward. FIG.
FIG. 3 is a perspective view showing another embodiment in which the torsion coil spring for urging the slider forward is attached to the lower half.

Hereinafter, the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a magnetic tape cassette according to the present invention is combined in a lid-like manner to form a housing, and an upper half 10 and a lower half 1 serving as a magnetic tape case (cassette case).
2. It mainly comprises a slider 14 provided in contact with the bottom surface of the lower half 12 from the outside and slidably mounted in the front-rear direction, and a magnetic tape 18 wound at both ends around a winding hub 16. ing. 4 except for a portion related to a slider spring 26 for urging the slider 14 forward.
This is basically the same as the conventional example shown in FIG.

In the magnetic tape cassette, both ends of a long magnetic tape 18 are fixed to a pair of winding hubs 16 and 16, and the magnetic tape 18 is wound from both ends to the respective winding hubs 16 and 1.
6 and a pair of take-up hubs 16, 16 on which the magnetic tape 18 is wound, are rotatable.
2 are housed in a cassette case in which lids are joined together, and the magnetic tape 1 between the pair of winding hubs 16
8 is stretched through a predetermined path so that only the overhanging portion 18a of the magnetic tape corresponding to the position of the magnetic head of the recording / reproducing apparatus (not shown) can be exposed to the outside.

In order to prevent a finger from contacting or dust adhering to the magnetic layer surface of the magnetic tape 18a in the overhanging portion that can be exposed from the cassette case, the upper half 1
At 0, a front cover 24 pivotally supported by a pin 24a is provided so as to swing between a closed position for covering the magnetic tape 18a of the overhang portion and an open position for exposing the magnetic tape 18a.

The cassette case is formed by connecting the upper half 10 and the lower half 12 each formed into a rectangular shape in a lid-like manner, and as described above, a pair of winding hubs 16 around which the magnetic tape 18 is wound. , 16 are rotatably housed, and various structures for holding the magnetic tape 18 and achieving predetermined functions are housed and held as described in detail below.

The take-up hub 16 is provided with a gear 16a integrally formed on the upper end surface thereof. This gear 16
a engages with the braking piece 20a of the brake member 20 incorporated in the upper half 10 to stop the rotation of the magnetic tape 18 in the loosening direction, and causes vibration in handling and transport of the magnetic tape cassette when not in use. This prevents the magnetic tape 18 from sagging due to shocks or impacts. A pair of brake pieces 20a engage with the corresponding gears 16a of the take-up hub 16, and a pin provided on the upper half 10 is provided. 10
The brake member 20 is spring-biased rearward toward the take-up hub 16 by a brake spring 22 formed of a torsion coil spring fitted to a.

When the magnetic tape cassette is not in use, the braking member 20a is engaged with the gear 16a by the urging force of the brake spring 22 so that the winding hub 16
The front cover 24 is rotated by the recording / reproducing device so that the front cover 24 is elongated from the left and right ends of the brake member 20 and is engaged with the front cover 24 when the recording / reproducing device is loaded. The brake arm 20b is pulled forward, and the brake piece 20a separates from the gear 16a, and moves to a release position where the winding hub 16 can rotate.

The lower half 12 has a bottom surface 12a having a rectangular shape.
6 is rotatably supported, and when a magnetic tape cassette is loaded into the recording / reproducing apparatus, a reel shaft (not shown) is inserted into the take-up hub 16 from the recording / reproducing apparatus.
Shaft insertion holes 12b, 12b for rotationally driving the reel 6
have. Further, the bottom surface 12a of the lower half 12
It has overhang portions 12c, 12c extending forward from both left and right ends, and a magnetic tape 18 stretched between a pair of winding hubs 16, 16 is provided on the left and right overhang portions 12c, 12c by a predetermined amount. Cylindrical tape guides 12d, 12d for guiding to the front of the cassette case through the path are provided upright from the bottom surface 12a. The left and right overhang portions 12c, 12c
The space between them is a space without the bottom surface 12a of the lower half 12, and forms an opening of the cassette case. The opening of the cassette case is a space into which a tape loading device (not shown) provided in the recording / reproducing apparatus enters when a magnetic tape cassette is loaded in the recording / reproducing apparatus.

The slider 14 is mounted on the bottom surface 12 of the lower half 12.
a thin flat bottom surface 14a provided in contact with a from below
And a pair of reel shaft insertion holes 14b, 14b provided on the bottom surface 14a.
2e, it is slidable in the front-rear direction. Then, it functions as a slider spring and is moved forward by being urged by the torsion coil spring 26 which is a feature of the present invention, thereby opening the cassette case and the reel shaft insertion hole provided in the lower half 12 on the bottom surface 14a. 12b, 12
b is closed to prevent dust and is moved rearward to open the opening of the cassette case, and is provided in the reel shaft insertion holes 12b, 12b provided in the bottom surface 12a of the lower half 12 and the bottom surface 14a of the slider 14. Reel shaft insertion hole 1
4b and 14b, the tape loading device and the reel shaft of the recording / reproducing device can be inserted.

On the bottom surface 12a of the lower half 12, there is provided an intermediate wall 12f curved in an arc shape along the magnetic tape 18 wound on the winding hub 16. This intermediate wall 12f
This protects the magnetic tape 18 by blocking the opening of the lower half 12 from the magnetic tape 18, and at the same time, forms the ribs of the lower half 12 to prevent the lower half 12 from being deformed. The two intermediate walls 12f are connected to each other at a central portion to form a connecting portion 12g, and a substantially triangular bottom surface 12h is provided in front of the connecting portion 12g with the opening. As shown in FIG. 2, the coil portion 26a of the torsion coil spring 26 for urging the slider is placed on the bottom surface 12h, and the spring receiving rib 14 provided in front of the slider 14 is provided.
By pressing c, it is urged forward (in the direction in which the slider 14 closes).

When the magnetic tape cassette is loaded in the recording / reproducing apparatus, the ribs 14d provided on the front surface of the slider 14 are pressed in conjunction with the operation of loading the magnetic tape cassette in the recording / reproducing apparatus. Automatically move rearward, and the left and right overhanging portions 12c, 12c of the lower half 12
Are opened, and the tape loading device of the recording / reproducing device can be inserted. The positions of the reel shaft insertion holes 12b, 12b of the lower half 12 and the reel shaft insertion holes 14b, 14b of the slider 14 match. Thus, the reel shaft of the recording / reproducing apparatus can be inserted.

At the lower end of the winding hub 16, a reel shaft connecting hole (not shown) for inserting and connecting a reel shaft provided in the recording / reproducing apparatus and rotating and driving each winding hub 16 is provided. . As described above, this reel shaft is inserted into the reel shaft connection hole of the winding hub 16 through the reel shaft insertion holes 14b and 12b provided in the slider 14 and the lower half 12, and is connected to the winding hub 16. The magnetic tape 18 taken out from the other take-up hub is wound on one take-up hub, and the magnetic tape 18 is fed to the magnetic head of the recording / reproducing apparatus at the overhanging portion 18a of the magnetic tape. It moves in contact with it and records information on or reproduces information from the magnetic tape.

Next, the details of the torsion coil spring 26 functioning as a slider spring will be described. As shown in FIG. 1, the slider springs 26 are preferably of substantially the same length on both sides from the central coil portion 26a, more preferably,
A torsion coil spring in which two arms 26b having symmetrical lengths protrude, and the tip of the arm 26b is configured such that the upper arm is positioned downward and the lower arm is positioned upward.
The arm 26b is bent substantially in parallel with a, and further bent rearward to form a substantially square bent portion 26c at the distal end of the arm 26b. When the torsion coil spring 26 is disposed between the lower half 12 and the slider 14 so as to bias the slider 14 forward, the connecting portion 12g of the intermediate wall 12f of the lower half 12 that is curved in an arc shape is used.
The coil portion 26a of the torsion coil spring 26 is placed on the substantially triangular bottom surface 12h formed in the above, and the bent portion 26c of the torsion coil spring 26 is arranged so as to abut a spring receiving rib 14c provided in front of the slider 14. So
The coil portion 26a of the torsion coil spring 26 has a connecting portion 12g.
The arm 26b of the torsion coil spring 26 is stably mounted by abutting the end of the substantially rectangular arm 26b against the spring receiving rib 14c.

That is, the coil portion 26a of the torsion coil spring 26 is formed by the arcuately curved intermediate wall 1 of the lower half 12.
Since it is arranged in the triangular recess formed in the connecting portion 12g of 2f, even if the position is slightly shifted at the time of assembly, it is naturally moved to the triangular recess by the biasing force of the spring itself and stabilized. Usually, it is not necessary to provide a boss or a pin for inserting a coil part required for assembling the torsion coil spring. Therefore, in the present invention, since there is no boss or pin for inserting the coil portion of the torsion coil spring, even if the position is slightly shifted at the time of assembling, there is no problem at all, and the assembling becomes very easy.

The arm 26 of the torsion coil spring 26
a bent portion 26b formed in a substantially square shape at the tip of
When the spring comes into contact with the spring receiving rib 14c, the spring comes into contact with a substantially rectangular surface, so that the spring moves to a naturally stable position and is stabilized by the biasing force of the spring itself. In the present embodiment, the bent portion 26b is configured to have a substantially quadrangular surface. However, even if the bent portion that bends backward as only the bent portion parallel to the coil portion 26a is omitted, It becomes a substantially triangular surface and has substantially the same effect.

FIG. 3 shows another embodiment of the mounting portion of the torsion coil spring 26. The housing wall 12 which fits with the coil portion 26a is provided around the coil portion 26a of the torsion coil spring 26.
i is provided. The storage wall 12 i is
6a so as to have a sufficient gap, and as in the embodiment of FIG. 2, there is no problem even if the position of the coil portion is slightly shifted during assembly. Is configured. The storage wall 12i on the side where the arm protrudes from the upper part of the coil part 26a of the torsion coil spring 26 (left side in the figure) is formed lower than the height of the arm so as not to interfere with the arm. The storage wall 12i on the side where the arm protrudes from the right side (shown on the right side) does not interfere with the arm, and is provided at a position from the position where the arm is bent most rearward to the rear.

The storage wall 12i is provided with the torsion coil spring 2
Between the time when the lower half 12 is moved and the position where the torsion coil spring 26 is moved between the time when the lower half 12 is positioned and the position where the torsion coil spring 26 is moved by being biased by the torsion coil spring 26, the torsion coil spring 26 comes off. In particular, a station for disposing the torsion coil spring 26 is different from a station for biasing the torsion coil spring 26 between the lower half 12 and the slider 14 in an automatic assembling machine. This is effective when assembling a magnetic tape cassette.

Although the magnetic tape cassette of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various improvements and changes can be made without departing from the gist of the present invention. Of course, you may.

[0037]

As described above, according to the present invention, the slider springs are provided on both sides from the center coil portion, preferably of approximately the same length, more preferably of symmetric length.
The torsion coil spring, which is a spring for biasing the slider, is constituted by a torsion coil spring having a protruding arm and a coil portion mounted on a concave portion of the connection portion of the intermediate wall curved in an arc shape of the lower half. Is stabilized by being pressed against the triangular concave portion of the connecting portion by the biasing force of the torsion coil spring itself, and there is no need to provide a boss or pin for inserting the coil portion necessary for assembling the torsion coil spring. Also, since there is no boss or pin for inserting the coil part, there is no problem even if the position is slightly shifted during assembly, and the assembly is very easy. In this case, a simple and inexpensive assembly head can be used.

Further, when the tip of the arm of the torsion coil spring is bent downward, the upper arm is bent downward and the lower arm is bent upward in parallel with the coil portion, the tip of the arm of the torsion coil spring is substantially bent. The spring is abutted against the spring receiver of the torsion coil by the bent portion constituting the surface, and is attached to a position that is naturally stabilized by the biasing force of the spring itself. In addition, by providing a storage wall around the coil portion of the torsion coil spring that has a sufficient clearance with the coil portion, the lower half can be biased until the torsion coil spring is biased and positioned. Is moved, the position of the torsion coil spring does not move largely and does not come off. in addition,
No expensive spring parts are required, and the assemblability is good.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a schematic configuration of an embodiment of a magnetic tape cassette according to the present invention.

FIG. 2 is a perspective view of a lower half showing details of an embodiment of a mounted state of a torsion coil spring for urging a slider of the magnetic tape cassette of the present invention forward.

FIG. 3 is a perspective view showing another embodiment of a mounted state of a torsion coil spring for urging a slider of the magnetic tape cassette of the invention forward.

FIG. 4 is an exploded perspective view showing a schematic configuration of an example of a conventional magnetic tape cassette.

FIG. 5 is an exploded perspective view showing a schematic configuration of another example of a conventional magnetic tape cassette.

FIG. 6 is a perspective view showing a slider urging leaf spring used in the magnetic tape cassette shown in FIG. 5;

[Explanation of symbols]

 10 upper half 10a pin 12 lower half 12a (upper half) bottom surface 12b (upper half) reel shaft insertion hole 12c overhang 12d tape guide 12e side wall 12f intermediate wall 12g connecting portion 12h (triangular) bottom surface 12i storage wall 14 Slider 14a (Slider) bottom surface 14b (Slider) reel shaft insertion hole 14c Spring receiving rib 14d Rib 16 Take-up hub 16a Gear 18 Magnetic tape 18a Overhanging portion 20 Brake member 20a Brake piece 20b Brake arm 22 Brake spring 22 Front cover 24a Pin 26 Torsion coil spring 26a Coil part 26b Arm 26c Bent part

Claims (1)

[Claims] An end of a long magnetic tape is wound around a pair of winding hubs and fixed, and the pair of winding hubs wound with the magnetic tape are rotatably stored in a cassette case.
A magnetic tape cassette in which the magnetic tape between the pair of winding hubs is stretched through a predetermined path, and only the magnetic tape at a position corresponding to a magnetic head is configured to be exposed to the outside, A cassette case comprising an upper half and a lower half, which rotatably accommodates the pair of winding hubs; and a lower case that is slidably mounted in a front-rear direction along a bottom surface of the lower half of the cassette case. And a slider urged in a direction to close the opening and the reel shaft insertion hole so as to open and close the opening at the front lower side and the reel shaft insertion hole at the bottom surface from the outside of the bottom surface, and urge the slider. A spring for biasing the slider, a torsion coil spring having a coil portion at the center and arms on both sides, the lower half facing the opening, and An intermediate wall having a concave portion for supporting the coil surface of the coil portion of the torsion coil spring is erected from the bottom surface, and the bottom surface is provided with a concave portion of the intermediate wall so as to support a bottom portion of the coil portion of the torsion coil spring. A magnetic tape, further extending to the opening side, wherein a spring receiving rib for supporting the distal ends of the two arms of the torsion coil spring is provided upright from the bottom surface for insulating the slider. cassette.