JPS6317101Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape cassette, and more particularly to a novel compact cassette of approximately the same size as a so-called Phillips type cassette.

In recent years, cassette tape recorders have become smaller and lighter, and the magnetic tape cassettes used in them have also become smaller, creating a strong desire for something that can handle long-term, high-quality, high-density recording and playback. I'm getting used to it.

However, conventional compact cassettes commonly used for audio and the like record and reproduce data using analog signals, and when high-density recording and reproduction is desired, this analog system naturally has its limits. Under these circumstances, by using a digital method such as pulse code modulation (PCM), which converts the input signal into pulses and performs recording and playback, it is possible to avoid being affected by the signal communication path and the quality of the recording medium. It is known that high-density recording and reproduction can be performed without any problems.

In addition, recent research and development has led to the development of a magnetic head that can perform high-density recording and playback such as multi-track even on narrow magnetic tapes used in Philips type tapes. It has become possible to record and play multi-tracks even on compact cassettes that are comparable to the cassette type.

When performing multi-track recording using the fixed head method on the compact cassette, for example, suppose 36 tracks are recorded in a round trip.
The width of one track is about 100 μm, which is extremely narrow compared to the four tracks in a conventional Philips type cassette. As a result, the effective sliding contact surface between the recording track of the magnetic head and each track is reduced, and the influence of dust that adheres to the magnetic tape and enters between the sliding surfaces on the recording and playback characteristics is much greater than in the past. growing.

On the other hand, among magnetic tape cassettes that use high-density recording and reproduction, video tape cassettes that use a rotating head system are generally popular. Since this video tape cassette protects the magnetic tape and performs high-density recording and reproduction, a rotatable guard panel is provided at the opening in front of the cassette to prevent the influence of dust. In the case of this rotating head system, except for special types of cassettes, recording and playback can only be performed on the magnetic tape running in one direction, and the cassette case has a so-called so-called cassette case in which side A and side B can be used. There was no need for a structure that could be used on both sides. Furthermore, in the rotating head method, two magnetic heads normally alternately slide against the magnetic tape while rotating at a fixed angle with respect to the tape running direction, so the magnetic heads have the effect of sweeping out dust. Compared to the fixed head method, the influence of dust on the recording and reproducing characteristics was less.

However, the magnetic tape cassette to which the present invention is directed uses a fixed head system, such as the Phillips type, and has a large number of recording tracks, and uses the upper and lower halves of the magnetic tape for recording and reproduction. , A side, and B side (front and back of the cassette) can be used. If the cassette is of a fixed head type, as mentioned above, the recording and playback characteristics are more likely to be affected by dust than if it is a rotating head type, so it is necessary to have a more reliable dust-proofing effect than the guard panel of the video tape cassette. A guard panel is required.

In view of the above problems, it is an object of the present invention to provide a new magnetic tape cassette which has a guard panel with a reliable dustproof effect, can be used on both sides, and is suitable for multi-track recording and reproduction.

The purpose of the present invention is to provide a cassette case with a built-in pair of hubs wrapped with magnetic tape.
In a magnetic tape cassette having an opening for inserting a magnetic head, a slide groove is formed behind the opening and on the upper and lower outer surfaces of the cassette case along the left-right direction of the cassette case, and the slide groove has a substantially U-shaped vertical cross section. a pair of slideable guard panels that are provided with a sliding portion that engages with the groove, and that have a concave portion and a convex portion of the same shape in vertically symmetrical positions on a side end surface near the center of the cassette, and that close the opening; This is achieved by a magnetic tape cassette comprising means for biasing the guard panel in the direction of closing the opening, and further characterized in that the entire cassette can be used both sides.

Hereinafter, the present invention will be described in detail based on embodiments illustrated in the drawings.

FIG. 1 is a perspective view showing one embodiment of the present invention.

In FIG. 1, a magnetic tape cassette 1 is a compact cassette having a size comparable to that of a conventional Phillips type. The magnetic tape cassette 1 is provided with a rectangular opening 3 at the center of the front surface of the cassette case body 2, which is recessed toward the rear of the cassette. It is installed so that it slides open in the left and right directions. The opening 3 is a portion into which a recording/reproducing head, an erasing head, a pinch roller, and a capstan of a recording/reproducing apparatus are inserted.

A magnetic tape T wound around a pair of hubs (not shown) is housed in the cassette case body 2 so as to be able to run across the opening 3 from side to side. The hub has a pair of shaft insertion holes 5 into which the drive shaft of the recording/reproducing device is inserted.
They are arranged in the same manner as before. Although not shown, the front opening 3 includes a shield plate for blocking external noise during recording and reproduction, and a plate having a pressure pad for ensuring sliding contact between the magnetic tape T and the magnetic head. A spring may be provided.

As shown in FIG. 2, the guard panel 4 is composed of a front wall 6 and upper and lower end pieces 7, and has a substantially U-shaped vertical cross section and is configured to cover the opening 3. In the figure, the guard panel 4 on the left side when viewed from the front of the cassette moves to the left (direction B), and the guard panel 4 on the right side moves to the right (direction C).
direction) so as to be slidable in each direction.

Two slide grooves 11 are provided in the upper and lower outer surfaces of the cassette case slightly behind the opening 3, which are formed in series along the lateral direction of the cassette case. Furthermore, sliding portions 8 are formed at the tip ends of the upper and lower end pieces 7 of the guard panel 4, respectively, so as to protrude along the left-right direction of the guard panel 4 so as to face each other. The guard panel 4 is attached so that the slide portion 8 engages with the slide groove 11.

Furthermore, a recess 9 is vertically symmetrically formed in the center of the upper and lower edges 16 of the front wall 6 of the guard panel 4. The recess 9 is an engagement portion through which opening means provided in the cassette insertion section slides the guard panel 4 in the left and right directions when the magnetic tape cassette 1 is loaded into a recording/reproducing apparatus.

A spring storage groove 13 is formed in the front side wall 12 of the cassette case main body 2, and the spring storage groove 13 divides the front side wall 12 into upper and lower halves, and a compression spring 14 is provided in each of the spring storage grooves 13. There is.
Further, in the guard panel 4, a protrusion 10 formed inside the front wall 6 is inserted into the spring storage groove 13, and the compression spring 14 is inserted into the protrusion 10.
Due to this contact, the guard panel 4 on the right side is always urged leftward, and the guard panel 4 on the left side is always urged rightward.

The guard panel 4 on the right side is regulated to a position where it closes the opening 3 by the end of the slide section 8 closer to the center of the cassette coming into contact with the left end of the slide groove 11 on the right side. The closed position of the guard panel 4 is similarly regulated. Further, a notch 15 is formed in a portion of the slide portion 8 that is closer to the center of the cassette, so that the side end surfaces 20 (see FIG. 3) of both the guard panels 4 are surely brought together. in this way,
By configuring the slide groove 11 and the slide portion 8, the guard panel 4 can reliably close the opening 3 even if the compression forces of the compression springs 14 disposed on the left and right sides are different.

Note that the spring storage groove 13 accommodates the compression spring 1.
The cross-sectional shape is configured to widen toward the rear of the cassette so that the cassette 4 does not protrude toward the front of the cassette.

FIG. 3 shows an enlarged perspective view of the side end surface 20.

In FIG. 3, the U-shaped side end surface 20 located near the center of the cassette has a trapezoidal recess 17.
Similarly, a trapezoidal convex portion 18 is formed.
The concave portion 17 and the convex portion 18 have exactly the same shape, and are formed at symmetrical positions with respect to the vertical direction of the guard panel 4.

That is, both guard panels 4 have exactly the same shape. Therefore, both the guard panels 4
When the respective recesses 17 and protrusions 18 are closed,
are fitted into each other, and the side end surfaces 20 are in close contact with each other.

The material of the cassette case body 2 may be a conventionally used plastic resin such as polyacetal or ABS resin, and is not particularly limited. Further, it is desirable that it has appropriate elasticity so that it can be easily attached to the cassette case body 2.

The magnetic tape T may be a ferromagnetic iron oxide or chromium dioxide tape, but is preferably a metal tape or a vapor-deposited tape suitable for high-density recording and reproduction.

When the magnetic tape cassette 1 is loaded into a recording and reproducing apparatus, the guard panel 4 is opened by an opening means provided in the cassette insertion section, and recording and reproduction on the magnetic tape T becomes possible. or,
When the magnetic tape cassette 1 is taken out of the recording/reproducing apparatus again, the guard panel 4 is automatically closed by the force of the compression spring 14, and the opening 3 is completely closed.

The guard panel 4 has the recesses 9 formed vertically symmetrically as described above, so that the magnetic tape cassette 1 can be placed between the front and back (side A or side B).
It can be loaded in either direction and opened.

The magnetic tape cassette 1 constructed as described above
Since the guard panel 4 completely closes the opening 3 during storage, it protects the magnetic tape T located in the opening 3 and prevents dust from entering the cassette. This prevents damage to the magnetic tape T and deterioration of recording and reproducing characteristics.

Further, according to the present invention, since each of the guard panels 4 slides symmetrically to open the opening 3, the magnetic tape cassette 1 can be used on both sides, allowing multi-track recording using a fixed head system. Suitable for playback.

Further, the recessed portion 17 and the convex portion 18 are formed on the side end surface 20 of the guard panel 4, and when the opening 3 is closed, the uneven portion 1 of both guard panels 4 is formed.
7 and 18 are fitted into each other, so that the side end surface 20
They are firmly attached to each other without shifting.

Furthermore, since both the guard panels 4 attached to the magnetic tape cassette 1 have exactly the same shape, they can be manufactured using one mold, which is highly economical. It is.

In the embodiment described above, the recess 17 and the protrusion 18 are formed into a trapezoidal shape and are provided adjacent to each other, but they are not necessarily limited to such a shape and do not necessarily need to be provided adjacent to each other.

Although it was mentioned earlier that the present invention is applied to magnetic tape cassettes that are about the same size as conventional compact cassettes, it is not necessarily limited to this, and can also be applied to various other magnetic tape cassettes. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is a perspective view showing the inside of the guard panel of this embodiment, and Fig. 3 is an enlarged perspective view showing the side end surface of the guard panel of this embodiment. It is. 1... Magnetic tape cassette, 2... Cassette case body, 3... Opening, 4... Guard panel,
5... Shaft insertion hole, 6... Front wall, 7... Upper and lower end pieces, 8... Slide portion, 9... Dent, 10
... Protrusion, 11 ... Slide groove, 12 ... Front side wall, 13 ... Spring storage groove, 14 ... Compression spring, 1
5... Notch, 16... Upper and lower edges, 17... Recessed part,
18... Convex portion, 20... Side end surface.

Claims (1)

[Scope of utility model registration request] In a magnetic tape cassette that has an opening for inserting a magnetic head in the front of the cassette case in which a pair of hubs wrapped with magnetic tape are built-in, a magnetic tape cassette is provided at the rear of the opening and on the upper and lower outer surfaces of the cassette case in the left-right direction of the cassette case. A slide groove is formed along the cassette, and a slide portion having a substantially U-shaped vertical cross section and engaging with the slide groove is provided, and a concave portion and a convex portion of the same shape are provided at vertically symmetrical positions on the side end surface near the center of the cassette. The cassette is comprised of a pair of slideable guard panels of the same shape that close the opening, and a means for biasing both guard panels in the direction of closing the opening, and furthermore, the entire cassette can be used front and back. A magnetic tape cassette characterized by: