JPH0650874Y2 - Magnetic tape cassette - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a magnetic tape cassette, and more particularly to a novel compact cassette having a size substantially equal to that of a so-called Philips type.

2. Description of the Related Art In recent years, cassette tape recorders have become smaller and lighter, and the magnetic tape cassettes used for them have also become smaller, and there is a strong demand for those that can adapt to high-quality recording and reproduction over a long period of time. Is coming to Japan.

However, conventionally, the compact cassette generally used for audio and the like records and reproduces by an analog signal, and when high density recording and reproducing are desired, the analog system naturally has a limit. Under such circumstances, the quality of the signal communication path and the recording medium is affected by using a digital method such as pulse code modulation (PCM) that converts the input signal into pulse and performs recording and reproduction. It is known that high-density recording / reproducing can be performed without any problem.

In addition, recent research and development has led to the development of a magnetic head capable of high-density recording / reproducing such as multi-track even on a narrow magnetic tape used for the Philips type. It has become possible to record and reproduce multi-track on a compact cassette of the same type.

When the multi-track recording by the fixed head system is performed on the compact cassette, for example, if the reciprocating 36 tracks are recorded, one track width is 100.
The track width is about .mu.m, and the width of each track is extremely narrower than that of the conventional four-track cassette with four tracks. Therefore, the effective sliding contact surface between the magnetic head recording tracks and each track is reduced, and the dust that adheres to the magnetic tape and enters between the sliding contact surfaces has a much greater effect on the recording and reproducing characteristics than before. growing.

On the other hand, as a magnetic tape cassette using high-density recording / reproducing, a video tape cassette using a rotary head system is widely used. Since this video tape cassette protects the magnetic tape and records and reproduces at a high density, a rotatable guard panel that can open and close the opening in front of the cassette is provided to prevent the influence of dust. In the case of this rotary head system, recording / reproduction can be performed only for one-way running of the magnetic tape except for a special type of cassette, and the cassette case is a so-called front / back symmetrical type which can be used for A side and B side. No need for structure. Further, in the rotary head system, normally, two magnetic heads slidably contact the magnetic tape while rotating while being inclined at a certain angle with respect to the tape running direction, so that the magnetic head has a function of sweeping out dust. The influence of dust on the recording / reproducing characteristics was less than that of the fixed head method.

However, the magnetic tape cassette to which the present invention is applied uses a fixed head system such as a flip type and has a large number of recording tracks, so that recording and reproduction use upper and lower halves of the magnetic tape.
It can be used for the side B and the side B (front and back of the cassette). Since the cassette uses a fixed head system, the recording and reproduction characteristics are more likely to be affected by dust than the rotating head system as described above, and a guard panel having a more reliable dustproof effect than the video tape cassette is required. Becomes

Also, the magnetic tape cassette as described above is
ABS resin and PS resin are often used. Therefore, when the guard panel is opened and closed, resin shavings are generated on the surface where the guard panel and the cassette case are in sliding contact with each other. In particular, since the guard panel opens and closes the opening, shavings are generated in the vicinity of the opening in front of the cassette, easily enter the cassette through the opening and easily adhere to the magnetic tape, which significantly deteriorates the recording / reproducing characteristics. It has a great impact.

The present invention has been made in view of the above problems, and can open and close the opening in front of the cassette, and suppress the generation of shavings in the sliding contact portion with the cassette case during the operation. Equipped with a guard panel,
It is an object of the present invention to provide a new magnetic tape cassette capable of multi-track recording and reproducing on both front and back sides (A side and B side).

Configuration of the Invention The object of the present invention is to have an opening for inserting a magnetic head on the front surface of a cassette case containing a pair of hubs around which magnetic tape is wound, and the opening is closed so that the horizontal cross section is substantially U-shaped. In a magnetic tape cassette equipped with a guard panel, the guard panel is provided with one rotation support shaft at each end piece, and the cassette case is provided with the rotation support shaft on each of the cassette front sides of the left and right cassette side walls. V that spreads toward the front of the cassette that receives slidably forward
The guard panel has a bearing portion having an inclined wall surface, the guard panel has a sleeve made of a wear-resistant material mounted on the rotation spindle, and the biasing means is disposed on at least one side of the cassette side wall. Can be achieved by a magnetic tape cassette characterized in that it is urged toward the rear of the cassette by the above, and the entire cassette is symmetrical with respect to the front and back.

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

FIG. 1 is an exploded perspective view showing a magnetic tape cassette according to an embodiment of the present invention, and FIG. 2 is an enlarged exploded perspective view of a main part thereof. It should be noted that FIG. 1 is shown by appropriately cutting the guard panel for easier understanding of the present embodiment.

In FIG. 1, the magnetic tape cassette 1 is of the same size as the conventional Philips type. In the magnetic tape cassette 1, a rectangular opening 3 and a pair of holes 16 penetrating in the vertical direction of the cassette are formed on the front surface of a cassette case 2 composed of upper and lower halves, and a guard panel 4 for closing the opening 3 is formed. Is mounted so that it can swing vertically in the cassette. A recording / reproducing head of a recording / reproducing apparatus, an erasing head, and a pinch roller enter the opening 3.
The hole 16 is a portion into which the capstan enters.

A magnetic tape T, which is wound around a pair of hubs (not shown), is housed in the cassette case 2 so as to traverse the opening 3 left and right. The hub is arranged in the same manner as the conventional one, corresponding to the pair of shaft insertion holes 5 into which the drive shaft of the recording / reproducing device is inserted. Further, although not shown, the opening 3 is provided with a shield plate for shielding external noise during recording and reproduction, and a leaf spring provided with a pressure pad for ensuring sliding contact between the magnetic tape T and the magnetic head. May be provided.

The guard panel 4 is composed of a front wall 6 and left and right end pieces 7, and its horizontal cross section is substantially U-shaped. Each of the end pieces 7 has a rotation spindle 8 projecting in the cassette encasement at the center thereof. And is configured to cover the opening 3. or,
A sleeve 18 made of resin or metal such as POM or nylon, which has excellent wear resistance, is fixed to the rotary support shaft 8 so as not to come off. The guard panel 4 is attached to the cassette case 2 so as to be swingable in the vertical direction of the cassette by being biased rearward of the cassette by a tension spring 15 provided on one of the left and right cassette side walls 9.

The cassette case 2 is formed with a step portion 10 in which the left and right cassette side walls 9 fall toward the inside of the cassette at the front portion of the cassette, and a spring accommodating groove 13 which is connected to the step portion 10 and is depressed to the same depth. Is formed so as to extend rearward of the cassette at a position where the cassette side wall 9 is divided into upper and lower parts. Each of the step portions 10 is provided with a bearing portion 11 through which the rotary support shaft 8 having the sleeve 18 mounted thereon can slide in the cassette vertical direction.

That is, the bearing portion 11 is formed in a V shape having an inclined wall surface 12 that is symmetrical with respect to a line that divides the cassette side wall 9 into upper and lower parts, and that is inclined so as to spread toward the front of the cassette.

Further, notches 17 are formed at both front corners of the cassette case 2 along the thickness direction of the cassette.

In the guard panel 4, the tension spring 15 is connected to the rear end of the cassette of one of the end pieces 7 (right side in the drawing), and the other end of the tension spring 15 is located in the spring storage groove 13 toward the rear of the cassette. It is locked to the protrusion 14 provided on the. Therefore, the guard panel 4 is always biased to the rear of the cassette, and when the guard panel 4 is closed, the rotation support shaft 8 is in contact with the bent portion of the inclined wall surface 12.

The material of the cassette case 2 may be a plastic resin such as polyacetal or ABS resin which has been conventionally used,
It is not particularly limited.

Further, it is desirable that the material of the guard panel 4 is relatively inexpensive because it is easy to manufacture with a plastic resin such as polyacetal.

The magnetic tape T may be a ferromagnetic iron oxide or chromium dioxide type tape, but a metal tape or vapor deposition tape suitable for high density recording / reproduction is preferable.

When the magnetic tape cassette 1 constructed as described above is loaded into the recording / reproducing apparatus, the guard panel 4 is opened above the cassette by the opening means 20 provided in the cassette insertion portion. Hereinafter, the operation of the guard panel 4 by the opening means 20 will be described with reference to FIGS. 3 and 4.

The opening means 20 is a plate-like member that engages with either one of the left and right ends of the guard panel 4, and is provided at the inner corner of the cassette insertion portion.

Therefore, in the middle stage where the magnetic tape cassette 1 is inserted into the cassette insertion portion (direction of arrow C) and the magnetic tape cassette 1 moves downward (direction of arrow D), the lower edge of the front wall 6 is opened. It contacts the upper end of the means 20. This contact is performed at the position where the tip of the opening means 20 corresponds to the cutout portion 17. Thereafter, when the magnetic tape cassette 1 is further moved (D direction), the guard panel 4 is moved to the rotation support shaft 8 on which the sleeve 18 is mounted.
Rotates while moving upward while slidingly contacting the inclined wall surface 12 (direction of arrow E). Then, when the loading of the magnetic tape cassette 1 (movement in the direction of arrow D) is completed, the guard panel 4 is held in the upward open state by the opening means 20 and the opening 3 is opened.

In this way, the guard panel 4 is opened upward and the opening 3 is opened, so that recording / reproducing on the magnetic tape T becomes possible. Further, when the magnetic tape cassette 1 is taken out from the recording / reproducing apparatus, it moves in a stroke opposite to that at the time of loading, so that the engagement between the opening means 20 and the guard panel 4 is released. Therefore, the opening 3 is completely closed by the guard panel 4 being automatically closed by the force of the tension spring 15 (the direction opposite to the arrow E direction).

Further, since the magnetic tape cassette 1 is vertically symmetrical even when it is loaded upside down from the above case, the operation of the guard panel 4 is performed in the same manner. That is, the magnetic tape cassette 1 is capable of recording and reproducing the A side and the B side.

In the above-mentioned embodiment, the guard panel 4 is opened by moving the magnetic tape cassette 1 (in the direction of arrow D). However, in the magnetic tape cassette 1 of the present invention, the opening means 20 moves up and down. It may be used by being loaded in a recording / reproducing apparatus that operates so as to move.

Further, in the present invention, the entire shape of the bearing portion 11 is not limited to the V-shape as in the above embodiment, and a guide surface along the cassette front-rear direction that slidably receives the rotary support shaft in the front of the cassette is provided. It may have a shape. For example, as shown in FIG. 6, the bearing portion 11 is formed in an elongated hole having a guide surface 22 extending in the front-rear direction of the cassette, and the rotary support shaft 8 with the sleeve 18 attached thereto pulls the tension spring 15 from the tension spring 15. After being moved forward on the guide surface 22 against the force, the guard panel 4 can be opened and closed vertically in the cassette. In this case, a means for moving the guard panel 4 forward of the cassette is provided in the cassette insertion portion of the recording / reproducing apparatus.

Further, although the sleeve 18 is fixed to the rotary support shaft 8 in the above-described embodiment, the present invention is not limited to such an embodiment. For example, the sleeve 18 may be rotatably attached to the rotary support shaft 8. In this case,
After the sleeve 18 is loosely fitted to the rotary support shaft 8, the sleeve 18 is crushed so that the tip end portion of the rotary support shaft 8 has a large diameter.

Further, the bearing portion 11 in the present invention does not have to be a hole provided through the step portion 10 but may be a concave portion having the same shape as the V-shape shown in the above embodiment.

Further, the sleeve 18 in the present invention is not limited to the above-described aspect, and may have another shape. For example, as shown in FIG. 5, both ends of the sleeve 18a are formed into flanges having a diameter larger than the hole width of the bearing portion 11. The sleeve 18a is fixed to the rotary support shaft 8 or is rotatably mounted, as in the above-described embodiment.

When the sleeve 18a is used, the inner side surface of the end piece 7 and the step portion 10 do not come into direct contact with each other, so that the inner side surface and the step portion 10 are opened and closed when the guard panel 4 is opened and closed. It also prevents the generation of shavings due to friction with.

Effect of the Invention As described above, the magnetic tape cassette 1 of the present invention is used.
Is equipped with the guard panel 4 that can be easily opened on either the top or the bottom, so it is a magnetic tape cassette that is suitable for recording / reproducing multi-tracks that can be used on the front and back (sides A and B) of the fixed head system. Is. The guard panel 4 is provided with one rotation support shaft 8 on each of the both end pieces 7, and the cassette side wall 9 receives the rotation support shaft 8 slidably toward the front of the cassette. Since the bearing portion 11 having the inclined wall surface 12 is provided, the guard panel can be rotated in two directions, that is, the vertical direction, with an extremely simple structure. Moreover, since the rotation structure of the guard panel 4 is simple, the magnetic tape cassette 1 can be easily manufactured. Further, according to the present invention, when the magnetic tape cassette 1 is taken out from the recording / reproducing apparatus, the guard panel is rotated to the opening closed position by the action of the biasing means, and at the same time, the guard panel 4 completely closes the opening 3. Since the magnetic tape T is closed, the magnetic tape T located in the opening 3 can be protected and dust-proofed, and the magnetic tape T can be prevented from being damaged and the recording / reproducing characteristics can be prevented from being deteriorated.

According to the present invention, the rotary support shaft 8 has the sleeve 18 and
Since it is covered with a material with excellent wear resistance such as 18a,
When the guard panel 4 is opened and closed, the bearing portion 11
It is possible to suppress the generation of resin shavings in the sliding contact portion with and to suppress the deterioration of the recording / reproducing characteristics due to the shavings.
Further, the sleeves 18 and 18a allow the rotary support shaft 8
Since the wear deterioration of the guard panel 4 is suppressed, the operation of the guard panel 4 can be favorably maintained over a long period of time.

Further, according to the present invention, since the guard panel 4 can be opened with a very simple structure such as the opening means 20, the recording / reproducing apparatus is not complicated.

Although the present invention has been described above as being applied to a magnetic tape cassette having a size similar to that of a conventional compact cassette, the present invention is not limited to this, and can be applied to various other magnetic tape cassettes. .

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged exploded perspective view showing an essential part of the guard panel shown in FIG. 1, and FIGS. 3 and 4 are shown in FIG. FIG. 6 is an enlarged perspective view and a schematic side view showing the operation of the guard panel, FIG. 5 is an enlarged perspective view showing a modification of the sleeve of the present invention, and FIG.
The figure is an exploded perspective view of a main part showing a modified example of the bearing part in the present invention. 1 ... Magnetic tape cassette, 2 ... Cassette case, 3
…… Aperture, 4 …… Guard panel, 5 …… Shaft insertion hole, 6 …… Front wall, 7 …… End piece, 8 …… Rotary support shaft, 9 ・ ・ ・
… Cassette side wall, 10 …… Step, 11 …… Bearing, 12 ……
Inclined wall surface, 13 …… Spring storage groove, 14 …… Protrusion, 15 …… Tension spring, 17 …… Notched portion, 18, 18a …… Sleeve, 20 ……
Opening means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-51-70624 (JP, A) JP-A-60-55573 (JP, A) Practical application Sho-59-118184 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cassette case 2 containing a pair of hubs wound with a magnetic tape, has an opening 3 for inserting a magnetic head on the front surface, and the opening 3 is closed so that the horizontal cross section is substantially U-shaped. In the magnetic tape cassette provided with a guard panel 4, the guard panel 4 is provided with one rotation support shaft 8 on each end piece 7, and the cassette case 2 is rotated on each of the left and right cassette side walls 9 on the front side of the cassette. A bearing portion 11 having a V-shaped inclined wall surface 12 that spreads toward the front of the cassette and slidably receives the support shaft 8 in the front of the cassette;
Further, in the guard panel 4, sleeves 18 and 18a made of a wear-resistant material are attached to the rotary support shaft 8 and urging means arranged on at least one side of the cassette side wall 9.
The magnetic tape cassette is characterized in that it is urged to the rear of the cassette by 15, and the entire cassette is symmetrical on the front and back sides.