JPS6040964Y2 - Spiral magnetic recording and playback device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a spiral magnetic recording and reproducing device.

A spiral magnetic recording/reproducing machine is a device in which a magnetic head moves in a spiral manner, scans the magnetic surface of a magnetic sheet placed on a turntable, and performs recording and reproduction.

Next, one example will be described. The external appearance of this spiral type magnetic recording/reproducing machine is shown in FIG.

A magnetic sheet 3 is provided on the top plate 2 of the outer box body 1 of this regenerator.
The magnetic sheet 3 is placed in the correct position on the top plate 2 by three relatively short ruler pins 4.

A transparent presser plate 5 is hinged on one side edge of the outer box body 1, and this presser plate 5 presses the magnetic sheet 3 onto the top plate 2.

A large circular hole 2a is bored in the top plate 2, and the circular hole 2a
A decorative plate 6 that is substantially integrated with a turntable, which will be described later, is provided inside.

A groove 7 is cut into the decorative board 6 in the radial direction.
From inside the groove 7, the turntable 17 (see Figure 2)
A magnetic head 8 attached to the top protrudes.

The magnetic head 8 rotates together with the turntable 17, and is gradually advanced toward the center of the turntable by a feed screw, which will be described later, during the rotation of the bracket.

Therefore, as the turntable 17 rotates, the magnetic head 8 moves toward the center of rotation while tracing a spiral trajectory.

Audio recording and reproduction are performed by bringing the magnetic head 8 into contact with the recording/reproducing surface of the magnetic sheet 3 and sliding it in a spiral manner.

During recording and reproduction, rotation of the turntable is started and paused by operating the playback button 9, fast-forwarding of the turntable 17 is carried out by operating the fast-forwarding button 11, and reversing of the turntable 17 is carried out by operating the reverse button 12.

Further, the recording operation is performed by operating both the recording button 13 and the playback button 9, and each of these buttons is operated.

Recording, playback, fast forwarding, and reversing operations are performed by mechanisms not shown.

Reference numeral 14 is a power switch, 15 is a volume control knob, and 16 is a power switch.
indicate counters that display the number of rotations of the turntable.

A turntable 17, to which the decorative plate 6 is integrally attached, is pivotally mounted on a shaft 18, as shown in FIG.

The base end of this shaft 18 is fixed to a main mounting plate (not shown).

The shaft 18 has a helical gear 21 that is substantially integral with the cylinder 19.
is fixed by a screw 22, and a helical gear 23 meshes with the gear 21.

The feed screw 24 to which the helical gear 23 is attached is supported parallel to the horizontal plane of the turntable 17 by having one end supported by a support member 26 fixed to the turntable 17 with a screw 25 and the other end supported by a support member 27. has been done.

The turntable 17 is rotated in the direction of arrow A by a drive source (not shown), and this rotational movement causes the helical gear 23 to rotate in the direction of arrow B.

Two guide rods 29a and 29b are attached between the upright portion 28a of the support member 28 fixed to the turntable 17 and the bent pieces 28b and 28c, respectively.

A movable table 31 is attached to the guide rods 29a and 29b, and an elevating plate 35 on which a magnetic head 8 is fixedly fitted is loosely fitted into two guide rods 32 and 33 set on the movable table 31. ing.

An extensible spring 34 is provided between the elevating plate 35 and the movable table 31, and the elasticity of this spring 34 causes the elevating plate to
5 is given a rising habit.

However, this rising of the elevating plate 35 is due to the fact that one end 35 of the elevating plate 35
This is prevented by abutting on an adjustment lever (not shown).

On the other hand, a base 36b of an engaging arm 36, which has an L-shaped plane and a knife edge 36a at its free end, is fixed to the movable table 31.

A knife edge 36a of this engaging arm 36 engages with the above-mentioned feed screw 24.

The feed screw 24 rotates in the direction of arrow B together with the helical gear 23 as the turntable 17 rotates in the direction of arrow A.

As a result, the knife edge 3 is rotated by the rotation of the feed screw 24.
The movable carriage 31 is gradually sent in the radial direction via 6a.

Therefore, in FIG. 2, as the turntable 17 rotates, the magnetic head 8 moves toward the center of the turntable 17 while drawing a spiral trajectory.

In this way, the magnetic head 8 moves in a spiral manner, thereby scanning the magnetic sheet 3 and performing recording or reproduction.

The above is an overview of the spiral magnetic recording and reproducing machine.

The width of the magnetic track spirally formed on the magnetic surface of the recording sheet by the magnetic head 8 is 0.8 mm, and the distance between the track widths is 0.45rrI! It is IL.

Therefore, one pitch has a width of 1.25 mm.

With this track width, the magnetic head scans the magnetic surface of the magnetic sheet while the turntable rotates about 30 times, ie, while the turntable rotates three (2) times.

Furthermore, since it takes about 8 seconds for one turn of the turntable, the magnetic sheet 3 can record or playback for about 4 minutes.

However, the spiral magnetic recording/reproducing machine configured in this way does not move the recording medium as in the case of records and magnetic tapes, but fixes the magnetic sheet 3, which is the recording medium, and moves the magnetic head 8. Since magnetic recording and reproduction are performed by moving the magnetic head in a spiral manner, the mechanism for moving the magnetic head becomes very complicated as described above.

For this reason, most conventional magnetic sheet recording/playback machines are not equipped with a degaussing device on the main body of the recording/playback machine, and when erasing the magnetic recording on the sheet, a separate degaussing device such as a bulk eraser is used. It had been erased.

Furthermore, if a degaussing device is added to the main body of the recording/playback device, it must be installed in front of the recording/playback head in the direction of travel, and it must also be able to move in an accurate spiral.

However, the mechanism for moving the two heads, the recording/playback head and the erase head in a spiral along the same locus and moving each of them toward the center of rotation, is not only extremely troublesome, but also requires electrical circuits for recording and erasing. An electric circuit dedicated to the erasing head, which is completely separate from the reproducing head, is required.

Therefore, a sliding device with 3 or 4 circuits is required.
Furthermore, this also involves complicated technical problems such as crosstalk between circuits.

However, a recording/playback machine without a degaussing device is very inconvenient, but if it is equipped with a degaussing device, it can perform the same functions as a tape recorder.

An object of the present invention is to provide a spiral type magnetic recording and reproducing device with a degaussing function and an additional feature using a simple mechanism.

That is, when recording once and reproducing it, the magnetic head must always be returned to its original position, in other words, to the starting position.

Furthermore, when returning, if the turntable on which the magnetic head is attached is rotated in the opposite direction, the magnetic head will move in the opposite direction along the trajectory traveled during recording.

Therefore, when returning, if an erasing current is applied to the previous recording/playback head, the recording on the recording band will be demagnetized.

This is the idea! When the magnetic head returns to its starting position after recording, it cleverly takes advantage of the fact that it can follow the same trajectory in reverse as it did during recording, and at this time an erasing current is applied to demagnetize unnecessary recordings. This is what I did.

In this way, the three functions of recording, playback, and erasing can be performed with only one hem lower device and sliding device, so it is very easy to add a degaussing function to a conventional spiral type magnetic recording/playback device. I can do it.

The present invention will be explained below with reference to figures.

FIG. 3 is a block diagram of the electric circuit during recording and erasing of the spiral type magnetic recording and reproducing apparatus of the present invention.

During recording, the output of the microphone M is amplified by an amplifier Am, and this output is further amplified by an amplifier Am2, and then sent to a trap circuit T.

The signal is applied to the recording/playback heads R, P, and H via.

An alternating current bias is applied to the recording/reproducing heads R, P, and H from an oscillator O3C via a transformer T.

On the secondary side of the transformer T is a switch S that changes the oscillation output.

is inserted, and this switch S is used when recording.

The contacts are also switched so that appropriate bias currents flow through the recording/playback heads R, P, and H.

Also this switch S.

Contact. When the switch is switched to the positive side, the output of the oscillator O3C is increased, and the bias current flowing through the recording/playback heads R, P, and H is increased until the recorded signal is erased.

Also this switch S.

is linked to the switch S inserted between the amplifiers Am1 and Am2.

During recording, the contact of switch S is switched to contact a, and the switch S is switched to contact a.

Contact. When the switch is switched to , the switch S is configured to switch along the contact point.

When the reverse rotation button 12 (see Fig. 1) is pressed, these switches S and So are pushed together with a switch (not shown) that rotates the motor in the reverse direction, and their contacts are brought into contact.
It is now possible to switch to bo.

Further, when only the recording button 13 (see FIG. 1) is pressed, the switches S and So are switched to the contact a and the contact point a.

There is also a trap circuit T formed by a capacitor C and a coil L.

This prevents the bias current from affecting the amplifier Am during recording.

Further, capacitor co is a coupling capacitor.

According to the present invention configured in this way, when the recording button 13 is pressed during recording, the contacts of the switches S and So are switched to a and brown, respectively, and the output of the microphone M is transmitted to the amplifiers Am□ and Am2. The bias current is applied to the recording/playback heads R, P, and H through which a bias current is flowing, and this is recorded on the magnetic sheet.

After the spiral recording has been made in this manner, if you want to erase this recording, you can press the reverse button 12 over the recording button 13.

When this is pushed in, the contacts of the switch S are switched from a to b, thereby short-circuiting the output of the amplifier Ar'r11, in other words, the output of the microphone M.

The contact point is , the bias current is increased until it erases the previously recorded signal.

In this state, the motor rotates in reverse, so the recording/reproducing heads R, P, and H function as erasing heads and return to the starting position by tracing the recorded track in reverse.

Therefore, the recording band is erased in this process.

Further, in the above example, the changeover switch S is set to the amplifiers Am and A.
m2, which is an amplifier AJ'r12 and a trap circuit T as shown by the chain line.

Of course, it may be inserted between.

Furthermore, in the above example, the recording/playback heads R, P.

The erase current flowing through H was applied to this by increasing the output of the oscillator O3C, but this also required a DC power source and a selector switch S.
.

Of course, direct current erasure may also be performed by connecting a switch S□, which replaces the switch S□, between both terminals of the recording/playback heads R, P, and H as shown by the chain line.

As described above, by reversing the moving direction of the magnetic head relative to the magnetic sheet during recording and erasing, and using the magnetic head as an erasing head, it is possible to erase a completely recorded recording band.

Also, in the example above, when the record button and reverse button are pushed in, the magnetic head changes from the recording/playback head to the erase head, and the motor is reversed. In this case, it goes without saying that an erasing current may be applied to the magnetic head to reverse the motor.

Furthermore, it is generally known that in order to completely trace and demagnetize a magnetic recording medium, the width of the erasing head is made wider than the width of the magnetic head.

To satisfy this requirement, the magnetic head may be configured as shown in FIG.

FIG. 4 is a plan view of the magnetic head device viewed from directly above, with the widths of the left and right cores being changed from the gap.

That is, as shown in FIG. 5, the core 40 has a gap 40a as a boundary, the core 40b on the left is thin enough to correspond to the width of the recording/playback track, and the core 400 on the right is thin enough to correspond to the width of the erase track. Form thick.

This may be housed in the head housing 41.

It is generally known that the track width of a magnetic track varies depending on the width of the core that slides in advance.

Therefore, the magnetic head formed in this manner may be moved in the direction of arrow E during recording and reproduction, and may be moved in the direction of arrow E during erasing.

Alternatively, it may be configured as shown in FIGS. 6 and 7.

That is, the head housing 41 is shaped like a short cylinder and is rotatably supported by a support shaft 42 passing through the center.
Inside this cylindrical housing 41, wide erasing heads E and H are provided.
and Sayama's recording/playback heads R, P, and H, respectively.

The coils wound around the heads E, H and R, P, H are drawn out to contacts 43, 44, respectively.

One side of these contacts 43 and 44 is always the sliding brush 45.
．． 46.

That is, when the recording and reproducing heads R, P, and H are in contact with the magnetic surface of the magnetic sheet 3, the contactor 43 is in contact with the sliding brush 45.
When the erasing heads E and H are in contact with the magnetic surface of the magnetic sheet, the contactor 44 contacts the sliding brush 46 and supplies an erasing current to the coil. supply.

By configuring the magnetic head device as described above, when the magnetic head device moves in the direction of the arrow, the cylindrical housing 41 that is in contact with the magnetic surface of the magnetic sheet 3 moves counterclockwise around the support shaft 42. Since rotation is applied, the erasing head EH is brought to a position where it comes into contact with the magnetic surface, and the pin 47 fixed to the cylindrical housing 41 abuts against the stopper pin 49, thereby erasing data on the magnetic surface. Heads E and H are arranged opposite each other, and an erasing current is supplied to perform demagnetization.

Next, when the magnetic head device moves in the direction of arrow E to perform recording or playback, the cylindrical housing 41 in contact with the magnetic surface of the magnetic sheet 3 rotates clockwise around the support shaft 42 due to friction. As a result, the recording/playback heads R, P, and H are brought to a position where they come into contact with the magnetic surface, and the pin 47 abuts against the stopper pin 48, causing the recording/playback heads R, P, H is placed opposite the magnetic surface.

A recording current is then supplied to perform the recording operation.

Even in this case, the head width can be made different during recording and playback and when erasing.

As described above, the present invention skillfully utilizes the fact that when the magnetic head device returns to the starting position after recording, it traces the same trajectory in reverse as it did during recording, and at this time, the erase current is applied. Since it is designed to demagnetize unnecessary recordings by flowing the magnetic head, one magnetic head device can perform the three functions of recording, erasing, and reproducing.

Moreover, a degaussing function can be added very easily.

Note that even if you press the reverse button during playback, the recording circuit is not working, so the degaussing function will not work, and you will still be able to repeat as before.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a spiral magnetic recording/playback device, FIG. 2 is a perspective view showing a mechanism in which a magnetic head device moves in a spiral shape, and FIG. 3 is a perspective view of a spiral magnetic recording/playback device of the present invention. Block diagram showing an example of an electric circuit during recording and erasing, No. 4
The figure is a plan view showing an example of a magnetic head device, and FIG.
FIG. 6 is a sectional view showing another example of the magnetic head device, and FIG. 7 is a plan view of FIG. 6.

Claims (1)

[Claims for Utility Model Registration] A spiral magnetic recording/playback machine that performs magnetic recording and playback by spirally scanning a magnetic surface of a fixed magnetic sheet with a magnetic head, comprising: a recording/playback head and the head of said head; a head support member having an erasing head having a head width wider than the width of the erasing head so as to be switchable in accordance with the scanning direction; means for rotating the head support member in a recording/playback direction; and a means for rotating the head support member in the direction. and a means for supplying an erasing current to the erasing head during an erasing operation, wherein the magnetic head and the magnetic A spiral magnetic recording and reproducing device comprising an erasing device that erases data by switching to the erasing head by friction with a sheet.