JP2000021123A - Magnetic tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the accuracy of spring force, and to maintain proper energizing force over the entire range of the spring opening angle of a slider spring. SOLUTION: A magnetic tape cassette is provided with upper and lower halves 12 that compose a cassette case for accommodating a pair of winding hubs where a magnetic tape is wound and is connected in a lid-matching shape so that merely the magnetic tape of a part being extended between a pair of winding hubs is exposed, a slider that can slide between opening and closing positions for opening and blocking a guide insertion part at the front side of the cassette case and a reel shaft insertion hole 12a on the bottom surface of the lower half 12 and is fitted onto an lower surface outside the lower half 12, and a U-shaped leaf spring that is provided between a wall-shaped member being provided on the bottom surface of the lower half in a mountain shape and the slider and energizes the slider to the closing position. In this case, in the magnetic tape cassette, a rib being brought into contact with the leaf spring should be provided outside the wall-shaped member when the slider is set to the opening position.

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 using a U-shaped leaf spring as urging means for a slider mounted on a lower half.

[0002]

2. Description of the Related Art As is well known, a magnetic tape cassette such as a DDS or a DAT has a pair of take-up hubs or a pair of winding hubs each having a long magnetic tape fixed at each end and wound around the magnetic tape. The take-up reel is housed in a cassette case (cassette body composed of an upper half and a lower half joined in a lid-like manner) exposing only a portion of the magnetic tape stretched between the two hubs. Is done.
Since high-density recording is performed on the magnetic tape, it is necessary to improve the hermeticity of the case, especially in order to prevent the fingers from contacting the magnetic tape and the attachment of dust. Therefore, a slider is provided on the outer lower surface of the lower half so that the guide insertion portion on the front side of the cassette case and the reel shaft insertion hole on the bottom surface of the lower half can be opened and closed.

Further, the slider is provided with a wall-shaped rib along the back side of the magnetic tape at a portion stretched between a pair of take-up hubs to prevent dust from entering the cassette case. are doing. The slider is biased to the closed position (front side of the cassette case) by a substantially U-shaped leaf spring (slider spring).

FIG. 6 is a plan view showing an example of a lower half of a conventional magnetic tape cassette and a slider. Lower half 9
The bottom surface 90a of the "0" is provided with reel shaft insertion holes 90b, 90b. Although not shown, a winding hub around which a magnetic tape is wound is arranged. On the front side (upper side in the figure) of the lower half 90, two split tube-shaped ribs are continuously formed, and a C-shaped wall shape is formed along the outermost periphery of the magnetic tape wound on the winding hub. Is provided. A slider 94 is mounted on the lower side of the lower half 90 (back side in the figure) so as to be slidable in the front-rear direction (vertical direction in the figure) of the cassette. The slider 94 is provided with a wall-shaped rib (slider sliding wall) 94a in front of the slider 94 (upper side in the figure) along the back side of the magnetic tape exposed when the cassette is used. And
A U-shaped leaf spring (slider spring) 96 is provided between the U-shaped wall member 92 and the slider sliding wall 94a.
The tip 96a of the slider spring 96 contacts the slider sliding wall 94a to urge the slider 94 forward (upward in the figure).

The slider spring 96 has a U-shaped bottom 96
a comes into contact with the wall-shaped member 92 at two positions, and the contact point is used as a fulcrum of the load, and the tip end portion 96a is moved to the slider sliding wall 94a.
Energize. The slider spring 96 is required to be largely bent and deformed in accordance with the sliding back and forth of the slider 94 in order to obtain a stable operation of the sliding back and sliding of the slider 94. It is required that a predetermined urging force be stably exerted in a large stroke range in which the object slides.

[0006]

However, a slider spring having a conventional shape has the following problems. That is, as shown in FIG. 7, when the slider 94 is at the open position where the slider 94 slides backward (downward in the figure), the slider spring 96 is largely open. As a result, as shown by reference numeral A in the figure, the slider spring 96 and the U-shaped wall-shaped member 92 come and go. As described above, when the contact area between the slider spring 96 and the U-shaped wall-shaped member 92 is increased, there is a problem that the distal end portion 96a of the slider spring 96 cannot properly bias the slider sliding wall 94a. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. Even when the slider is in the open position, the slider spring and the wall-shaped member do not come into contact with each other, or come into contact with each other.
It is an object of the present invention to provide a magnetic tape cassette capable of improving the accuracy of a spring force over the entire range of a spring opening angle of a slider spring, maintaining an appropriate biasing force, and ensuring stable sliding of a slider.

[0008]

According to the present invention, there is provided a cassette case for accommodating a pair of winding hubs each having a magnetic tape wound thereon, the cassette case being provided between the pair of winding hubs. The upper half and the lower half which are joined together so as to expose only the magnetic tape of the stretched portion, and the guide insertion portion on the front side of the cassette case and the reel shaft insertion hole on the bottom surface of the lower half are opened. An open position and a slider mounted on the outer lower surface of the lower half so as to be slidable between a closed position and a closed position, and between the pair of winding hubs when the slider is in the closed position. A wall-shaped rib provided perpendicularly to the bottom surface of the slider along the back side of the magnetic tape in the stretched portion; Two split-tube type ribs in a row, Along the magnetic tape wound around the take-up hub, a C-shaped wall-shaped member, a C-shaped wall-shaped member provided on the bottom surface of the lower half, and the slider A U-shaped leaf spring that is provided between the provided wall-shaped ribs and abuts both ends opened in a substantially U-shape with the wall-shaped rib to bias the slider to a closed position; A magnetic tape cassette provided with ribs provided on the outside of the wall-shaped member so as to come into contact with the leaf spring when the slider is at the open position. I do.

[0009]

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 a magnetic tape cassette according to the present invention. The upper half 10 and the lower half 1 of the magnetic tape cassette are combined in a lid-like manner to form a housing that becomes a cassette case (cassette body).
2 and a slider 14 mounted on the lower outside of the lower half 12 so as to be slidable in the front-rear direction.

In a cassette case composed of an upper half 10 and a lower half 12, a magnetic tape wound and stretched around a pair of winding hubs (not shown) is accommodated. When the cassette is not used, the upper half 10 has a brake member 1 so that the take-up hub rotates and the magnetic tape does not slack.
6 are provided. The brake member 16 has two braking pieces 16a, 16a. The braking piece 16a engages with a gear provided on the winding hub, thereby inhibiting rotation of the winding hub. When the cassette is not used, the brake member 16 is biased by a brake spring 18 using a torsion coil spring so that the braking piece 16a is engaged with the gear.

[0012] Since high-density recording is performed on the magnetic tape, it is necessary to prevent the fingers and the dust from adhering to the magnetic tape. for that reason,
The upper half 10 is provided with a front lid (lid) 20 on the front surface of the upper half 10 to protect the portion of the magnetic tape stretched between the pair of winding hubs when the cassette is not used.

The lower half 12 has a rectangular bottom surface 12a.
And a reel shaft insertion hole 12b for inserting the reel shaft into the cassette case when the cassette is used, and a projecting portion 12 extending forward from both left and right ends of the bottom surface 12a.
c, 12c. Left and right overhang 1
2c and 12c have cylindrical tape guides 12d and 12d for guiding the magnetic tape of the portion stretched between the pair of winding hubs to the front surface of the case.
It protrudes perpendicularly to a. The left and right overhangs 12c,
The space between 12c is a space into which a so-called tape loading device provided on the deck side where the magnetic tape cassette is loaded enters.

The slider 14 is mounted on the bottom surface 12 of the lower half 12.
a, and slides in the front-rear direction of the cassette, but when in the closed position located in front of the cassette, the space between the left and right overhanging portions 12c, 12c of the lower half 12 and the reel shaft insertion hole. 12b, 12b is the bottom surface of the slider 14
By 4a, it blocks for dust prevention. Also,
When the slider 14 is at the open position located at the rear of the cassette, the space between the left and right overhanging portions 12c, 12c is opened, and two holes 14b, 14b provided on the bottom surface 14a of the slider 14 are formed as described above. Reel shaft insertion hole 12
b, 12b.

When the cassette is mounted on the deck, the slider 14 automatically comes to the open position by the action of the device in the deck. Further, when the cassette is not used, the slider 14 is mounted on the lower half 12
The slider is urged by a slider spring 22 composed of a U-shaped leaf spring and slides forward to be in a closed position.

Two split-tube-shaped ribs are formed continuously on the bottom surface 12a of the lower half 12 perpendicularly to the side facing the space between the left and right overhangs 12c, 12c (the side where the magnetic tape is exposed). A wall-shaped member 12e having a U-shape is provided. The C-shaped curved portion of the wall-shaped member 12e has a shape along the outermost periphery of the wound magnetic tape when the wound magnetic tape is placed on the winding hub. I have. A column-shaped rib 24 is provided substantially at the center of a bottom portion 12f divided into a triangular shape by a wall-shaped member 12e, and a slider spring 22 is mounted here.

When the cassette is not used, the slider 14 is urged by the slider spring 22 so as to be fixed at the front closed position. A wall-shaped rib (slider sliding wall) 26 perpendicular to the bottom surface 14a is provided.

The present invention is intended to appropriately maintain the biasing force of the slider spring 22 over the entire range of the spring opening angle. FIG. 2 is a plan view showing the lower half 12 of FIG. As shown in the figure, two semi-cylindrical members are provided outside the wall-shaped member 12e erected on the lower half bottom surface 12a and slightly inside (toward the center) from the position where the member 12e is curved outward. Are provided.

FIG. 3 is a front view seen from the direction of arrow III in FIG. As shown in FIG. 3, the semi-cylindrical rib 12g is provided at a height slightly lower than the wall-shaped member 12e near the center of a wall-shaped member 12e provided on the bottom surface 12a of the lower half 12. Have been. Also, FIG.
4 shows a cross-sectional view along the line IV-IV. The height of the rib 12g is not particularly limited, and will be described later in detail.
Is moved to the open position by sliding backward, and when the slider spring 22 is largely opened, the slider spring 22
It is sufficient that the height is equivalent to g.

FIG. 5 shows the lower half 12 and the slider 1 of FIG.
4 shows a plan view in which the slider spring 4 and the slider spring 22 are combined. In FIG. 5, the slider 14 is in the closed position (below the figure), and the slider spring 22 is largely open.
As shown in the figure, the slider spring 22 has a central bent portion 22.
a, in addition to contacting the wall-shaped member 12e at two places on the left and right
The left and right arms 22b, 22b are in contact with a rib 12g provided on the outside of the wall-shaped member 12e, and furthermore, both left and right tip portions 22c,
22c is in contact with the slider sliding wall 26 so as to urge it.

As described above, in this embodiment, since the arm 22b of the slider spring 22 is in contact with the rib 12g, the arm 22b comes into contact with the wall-like member 12e as in the prior art shown in FIG. Never, this rib 12g
The contact point with the contact point becomes a new load fulcrum, a more accurate spring force can be maintained, and the tip end portion 22c can properly bias the slider sliding wall 26.

The position of the rib 12g is such that the outside of the portion where the U-shaped wall-shaped member 12e is curved outwardly is
Since the contact point between the slider spring 22 and the arm 22b is close to the tip 22c, the slider spring 22 cannot properly function as a load fulcrum, and is meaningless. Near the center of 12e, the tip of the arm portion 22b is not preferable because it may still hit or hit the wall-shaped member 12e. After all, the rib 12g is preferably provided slightly inside the portion where the wall-shaped member 12e is curved outwardly. For example, in the present embodiment, 21 ° is exemplified as an angle indicated by θ in the drawing. The shape of the rib 12g is not particularly limited. However, since the slider spring 22 abuts and slides, if the rib has an angle, the slider spring 22 is damaged. Therefore, the rib 12g is preferably rounded. For example, in the present embodiment, a semi-cylinder having a curvature radius of 0.35 mm is exemplified.

In this embodiment, two ribs 12g are provided on the left and right of the U-shaped wall member 12e. However, the number of ribs is not limited to two. Many may be provided. In this case, in order for each to serve as a load fulcrum, it is necessary that the arm portion 22b hits in order from the one provided inside.

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

[0025]

As described above, according to the present invention, when the slider is in the open position, the slider spring comes into contact with the rib provided on the outside of the wall-shaped member. The contact point with the rib acts as a new load fulcrum, maintains a high-precision spring force, and the slider spring can properly bias the slider, so that the slider slides stably. Is done.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a lower half of FIG. 1;

FIG. 3 is a front view of the lower half of FIG. 2 as viewed from a direction III.

4 is a cross-sectional view of the lower half of FIG. 2 taken along the line IV-IV.

FIG. 5 is a plan view showing a state where the lower half of FIG. 1 is combined with a slider and a slider spring.

FIG. 6 is a plan view showing a state where a lower half of a conventional magnetic tape cassette, a slider and a slider spring are combined.

FIG. 7 is a plan view showing a state in which the slider is at a closed position in FIG. 6;

[Explanation of symbols]

 Reference Signs List 10 upper half 12 lower half 12a (lower half) bottom surface 12b reel shaft insertion hole 12c (lower half) overhang 12d tape guide 12e C-shaped wall-shaped member 12g rib 14 slider 16 brake member 18 brake spring Reference Signs List 20 front lid 22 slider spring (U-shaped leaf spring) 22a central bent portion (of slider spring) 22b arm portion (of slider spring) 22c tip portion of (slider spring) 26 slider sliding wall (wall-shaped rib)

Claims (1)

[Claims] 1. A cassette case accommodating a pair of winding hubs around which a magnetic tape is wound, and a lid-like shape so as to expose only a portion of the magnetic tape stretched between the pair of winding hubs. Upper and lower halves, which are slidable between an open position for opening a reel insertion hole on a bottom surface of the guide insertion portion and a bottom surface of the lower half of the cassette case, and a closed position for closing. A slider mounted on the outer lower surface of the lower half; and, when the slider is in the closed position, along a back surface of the magnetic tape in a portion stretched between the pair of winding hubs. A wall-shaped rib provided perpendicular to the bottom surface of the slider, and two split-tube-shaped ribs are formed continuously on the winding hub in a manner perpendicular to the bottom surface of the lower half where the magnetic tape is exposed. A letter C along the wound magnetic tape And the wall-shaped member provided on, provided between the wall-shaped rib provided on the wall-like member and the slider provided in the form of a slanted roof in the lower half bottom surface,
Both ends opened in a substantially U-shape are brought into contact with the wall-shaped ribs,
A U-shaped leaf spring for urging the slider to a closed position, wherein the U-shaped leaf spring contacts the leaf spring outside the wall-shaped member when the slider is in an open position. A magnetic tape cassette provided with ribs that are in contact with each other.