JPH045114Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a magnetic drum device in which a magnetic head is in sliding contact with the outer peripheral surface of the magnetic drum and records or reproduces audio information, etc. on a large number of tracks. This invention relates to an improvement in a magnetic drum cassette that is detachable from the apparatus main body, thereby making it possible to exchange recorded information in the field.

Recently, for example, 0K monitors for cars, vending machines,
Magnetic drum systems are used in announcement systems for various terminal devices. In a magnetic drum type audio output device, the recording medium layer on the surface of the magnetic drum is divided into a number of tracks, and information can be recorded and played back on each track via a magnetic head, so audio information can be directly processed. This is because it has the advantage of being able to access a large number of messages at random.

This type of magnetic drum device is small and lightweight;
It must also be highly durable. In order to make the magnetic drum more compact (reduced in diameter) for the same recording capacity, it is necessary to reduce its circumferential speed. Therefore, the required output level is secured by pressing the magnetic head against the surface of the magnetic drum, which causes wear and tear on the magnetic recording medium layer and the magnetic head, shortens its lifespan, reduces output, deteriorates sound quality, and furthermore causes high friction. In order to solve problems such as an increase in wow/flutter caused by resistance, a structure has been adopted in which oil is applied to the surface of the magnetic recording medium layer.

On the other hand, with the further miniaturization of magnetic drums, it is inevitable that the amount of recorded information will decrease to some extent. Even if there is no particular problem in normal use, depending on the time of use and purpose, there are many cases where it is necessary to distort, replace, or change the recorded information. Therefore, a magnetic drum cassette has been devised in which the magnetic drum is housed in a case and can be attached to and detached from the main body of the apparatus.

With such a configuration, there is a problem that the lubricating oil applied to prevent wear of the magnetic drum recording medium layer leaks from the magnetic drum to the inside and outside of the cassette during use. Various measures were taken to prevent this. One is a structure in which oil-absorbing rings for preventing oil leakage are fitted on both sides of the magnetic recording medium layer of the magnetic drum to absorb excess oil flowing down. When the cassettes are fitted together, a gasket is inserted into the gap between the cassettes and the cassette is fitted to prevent lubricating oil from leaking out of the cassette. However, according to the former, oil-absorbing rings are fitted to both ends of the magnetic recording medium layer, which increases the height of the magnetic drum accordingly, and also prevents the magnetic head from getting in the way. I had a problem. Furthermore, according to the latter method, when assembling the magnetic drum cassette, it is necessary to insert a gasket each time and screw the upper case part and the lower case part together, which requires a very time-consuming and troublesome work.

Furthermore, in this type of magnetic drum cassette, the cassette is removable, so when the magnetic drum cassette is replaced, the relative positional relationship with the magnetic head located on the main body of the device must always be accurate. There is. In other words, compatibility between magnetic drum cassettes is required. In particular, if the lower case part of the magnetic drum cassette is warped or otherwise deformed, the perpendicularity of the magnetic drum will be disrupted and the relative positional relationship with the magnetic head will be disrupted, making it difficult to read recorded information accurately. I become unable to do so. For this purpose, the thickness of the lower case portion must be made considerably thicker to prevent deformation such as warping, which also causes the problem that the magnetic drum cassette becomes heavier.

The purpose of the present invention is to eliminate these drawbacks of the conventional technology, to prevent the lubricating oil of the magnetic drum from leaking out of the cassette, to have an extremely simple structure, and to make the height of the magnetic drum unnecessarily high. To provide an improved magnetic drum cassette which does not increase the number of assembly steps, prevents deformation such as warping of the lower case part, and does not become heavy.

The present invention, which can achieve these objectives, has improved the structure of the lower case part of the magnetic drum cassette, and has a plurality of reinforcing beams integrally formed on the upper periphery and middle part. The recess formed thereby is used as an oil reservoir to prevent dripping lubricating oil from leaking outside.

Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an exploded perspective view showing one embodiment of the magnetic drum cassette according to the present invention. The magnetic drum cassette has a structure in which the magnetic drum 1 and its related parts are housed in a single case. The case consists of a lower case part 2 and an upper case part 3. The lower case part 2 has a substantially rectangular plate shape, and has a structure in which a bearing 4 is provided in the center, and positioning guide cylinders 5 are erected near the upper surface of three surrounding corners. This positioning guide tube 5 has a lid and no bottom, and has a function in which a guide pin provided on the magnetic drum device main body is fitted to set the magnetic drum cassette at a predetermined position, and also to uniquely determine the direction of the magnetic drum cassette. fulfill. A capstan insertion hole 7 is also formed in the lower case portion 2.

The magnetic drum 1 consists of a cylindrical drum body 10 mainly made of metal or synthetic resin, and a magnetic recording medium layer 11 attached to almost the entire outer peripheral surface. The magnetic recording medium layer 11 can be formed, for example, by kneading magnetic powder into rubber and fitting a magnetic rubber tube into a seamless tube shape onto the outer periphery of the drum body 10. Such a magnetic drum 1 is rotatably supported by inserting a drum rotating shaft 12 into a bearing 4 provided in the lower case portion 2. A circumferential groove 13 is provided on the lower end surface of the drum body 10, and a rubber tire 14, which is a friction ring, is fitted onto the inner wall of the groove 13, so that the outer circumference of the rubber tire 14 protrudes slightly within the groove. Then, the capstan (not shown in FIG. 1, see reference numeral 25 in FIG. 2) on the side of the magnetic drum device main body passes through the capstan insertion hole 7 and inserts the rubber tire 1.
It is designed so that it can be pressed against the outer peripheral surface of 4.

The upper case part 3 regulates the axial movement of the magnetic drum 1, and the lower case part 2
In combination, this constitutes a nearly closed case. In this embodiment, it is a rectangular prism with a lid and no bottom. In order to prevent the magnetic drum 1 from shaking inside the case, the gap between the upper end of the drum rotation shaft and the upper case part 3 should be minimized, or a leaf spring should be attached to the bottom surface of the lid to prevent the drum rotation shaft 12 from shaking. The structure should be such that it pushes downward. Further, a mechanism is provided on the inner wall of the upper case portion 3 to constantly apply oil to the surface of the magnetic recording medium layer 11 of the magnetic drum 1. In this embodiment, this oil application mechanism includes an oil pad 15 having a length approximately equal to the width of the magnetic recording medium layer 11.
is fixed to the end of the leaf spring 16, the other end of the leaf spring 16 is attached to the inner wall of the upper case part 3, and the elastic force of the leaf spring 16 causes the oil pad 15 to be attached to the magnetic recording medium layer 11. The magnetic recording medium layer 11 is configured to be pressed against it, so that as the magnetic drum rotates, oil is constantly and uniformly applied to almost the entire surface of the magnetic recording medium layer 11. In this way, the lower case part 2 and upper case part 3, which house the magnetic drum 1 and its related parts, are tightly fixed with screws or the like.

The present invention is significantly different from conventional devices of this type in the structure of the lower case portion. As is clear from FIG. 1, in the present invention, the lower case portion 2 has a partially thick structure in which a plurality of reinforcing beam portions 20 are integrally formed at the upper peripheral edge and the middle portion of the lower case portion 2. and the concave portion 21 created thereby
is an oil reservoir to prevent dripping lubricating oil from flowing out. Therefore, it is not necessary to fit an oil-absorbing ring onto the outer peripheral surface of the magnetic drum 1 used in this apparatus.

As mentioned above, in this type of magnetic drum cassette, the lower case part 2 needs to have good dimensional stability to prevent deformation such as warping, but according to the present invention, the middle part of the lower case part 2 beam part 2
Since the 0 is integrally formed, the mechanical strength is greatly improved and deformation such as warping can be prevented from occurring. Furthermore, since the recess is formed, the amount of material used is small and the weight does not increase significantly. Furthermore, the recess can be effectively used for other purposes, that is, as an oil reservoir to receive lubricating oil dripping from the magnetic drum. This is extremely effective in that there is no need to use a gasket or the like for prevention.

Further, as shown in FIG. 2, the magnetic drum used in the present invention is preferably provided with a mark 22 in advance at an appropriate position on the drum body 10 so as to indicate the recording start position. The mark 22 indicating the recording start position may be any arbitrary mark such as an arrow, a triangle mark, or a line. In addition, in the same figure, numeral 24 is a magnetic head, and numeral 25 is a magnetic head.
2 is a capstan for rotationally driving the magnetic drum 1, and 26 is a flyhole driven by a belt. In a magnetic drum for an audio output device, faithful reproduction of audio cannot be achieved unless the time required for one rotation of the magnetic drum is accurate. This is because if the rotation times differ for each audio output device, there will be differences in sound quality even if the recording source is common. In such a case, if the mark 22 is provided as described above, it will be extremely easy to adjust the rotation time. Also, since voice messages are recorded from a common fixed point (line) on the circumference of the magnetic drum for each track, in the standby state, the magnetic head is positioned on the magnetic drum at a fixed point near the recording start point of the voice message. There is a need. Therefore, as an item to check the operating state, it is necessary to confirm whether or not the magnetic head is at the above-mentioned fixed position during standby. Even if the static position of the magnetic drum deviates due to some kind of obstacle, if the above-mentioned mark 22 is attached, it can be easily seen visually, and such troubles can be easily discovered. Furthermore, when recording audio, the recording start position can be determined and the end position of one rotation can also be visually observed, so the recording can be performed without using a special recording device. Such marks 22 may be provided on any part of the magnetic drum 1. For example, in the case of a magnetic drum cassette as shown in FIG. 1, an opening 23 is provided for access by the magnetic head.
Since you can peek inside from the inside, it is necessary to attach it in a position where it can be seen from there. Note that this arrangement of marking the recording start position is not limited to the case of the magnetic drum cassette as described above, but can also be applied to an audio output device incorporating a magnetic drum.

Since the present invention is a magnetic drum cassette constructed as described above, the case can be made to have high mechanical strength, and the relative positional relationship with the external magnetic head can be adjusted to any type of cassette with less deformation such as warpage. This not only improves the reliability of the device, but also does not increase the weight unnecessarily and does not significantly increase the amount of material used. Since dripping lubricating oil can be reliably retained, there is no need for complex structures or cumbersome structures such as installing an oil-absorbing ring on the magnetic drum or assembling the upper and lower case parts with gaskets. No work is required, the structure of the magnetic drum cassette can be simplified, the lower case part can be integrally molded, making it easy to manufacture, and it can be assembled easily, among other excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of a magnetic drum cassette according to the present invention, and FIG. 2 is an explanatory view showing an example of a magnetic drum suitable for use therein. 1...Magnetic drum, 2...Lower case part, 3...
Upper case part, 11... Magnetic recording medium layer, 15...
Oil pad, 20... Beam portion, 21... Recessed portion.

Claims (1)

[Scope of utility model registration request] A lower case portion provided with a bearing in the center, a magnetic drum having a magnetic recording medium layer on the outer peripheral surface of a cylindrical drum body and rotatably supported by the bearing, and axial movement of the magnetic drum. an upper case part that controls the magnetic recording medium and forms a substantially closed case in combination with the lower case part; and an oil application mechanism that is attached to the inner wall of the case so that an oil pad comes into sliding contact with the surface of the magnetic recording medium layer. In the magnetic drum cassette, which is detachably attached to the magnetic drum apparatus main body, the lower case part has a structure in which a plurality of reinforcing beam parts are integrally formed on the periphery of the upper surface side and in the middle part. ,
A magnetic drum cassette characterized in that the resulting recess is used as an oil reservoir for preventing dripping lubricating oil from flowing out.