JPS6325528Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement of a demagnetizer for demagnetizing each part of a cassette tape recorder, particularly the magnetic head.

Normally, when a tape recorder is used for a long period of time, the magnetic field generated by the tape recorder tends to magnetize various parts including the magnetic head, capstan, etc. and deteriorate the recording and playback characteristics, so it is necessary to demagnetize the tape recorder at regular intervals. be. Conventionally, in order to facilitate degaussing of magnetic heads in cassette tape recorders,
As shown in FIG. 4, a degaussing signal generating circuit 42 is built into a case 41 of the same standard as a Philips type compact cassette, and a magnetic head insertion window 43 is built into the case 41.
The degaussing head 44 is slidably disposed corresponding to the degaussing head 44, and the head 44
switch 45 that operates on and off in conjunction with the reversal of the
A demagnetizer equipped with this has been proposed.

If a demagnetizer having such a configuration is continued to be used, the connecting wire 46 between the demagnetizing head 44 and the signal generating circuit 42 will suffer from bending fatigue, and the connecting wire 46 will easily break, and the magnetic head 44 itself will move back and forth. Because it can be housed in a cassette-like case so that it can be moved forward and backward, it has a small shape, and because of this, when it is pushed backwards by the magnetic head on the tape recorder side, smooth backward guidance may not be performed and it may tilt. However, the facing condition with the other head is unstable and non-uniform, and a sufficient demagnetizing effect cannot be obtained over the entire area.

The present invention was developed with attention to the above problem, and instead of moving the degaussing head, the entire main body case is movable, thereby ensuring reliable forward and backward guidance and cutting the connecting wire of the degaussing head. The purpose is to provide a demagnetizer that does not cause accidents.

The present invention will be specifically described below based on embodiments shown in the drawings.

The demagnetizer 1 according to the present invention is shown in FIGS. 1 and 2.
As shown in the figure, a degaussing signal generating section 3 that generates an attenuated alternating magnetic field and a switch section 4 that regulates the timing of operation of the signal generating section 3 are installed in a main body case 2 that has almost the same specifications as a Phillips-type compact cassette. It will be deployed.

The main body case 2 is made up of upper and lower cases 2a and 2b made of a synthetic resin material and are arranged in a lid-like manner, and has cutouts 7 and 7 is provided, and as shown in FIGS.
can be freely inserted and removed from the front 11 side of the main body case 2, and penetrates through the upper and lower cases 2a and 2b,
Elongated holes 13, 13 into which rotating shafts 12, 12 of the tape recorder 8 are inserted are provided. The long hole 13,1
3 extends from the rotary shaft insertion hole forming position in a normal compact cassette toward the front side of the case 11. Therefore, when the main body case 2 is set in the tape recorder 8, it extends toward the rear side 14 side. It can be slid forward and backward by the 15 minute gap that exists.

The switch part 4 includes a guide part 16 which is provided upright on the inner surface side of the upper and lower cases 2a and 2b surrounding the elongated hole 13;
a switch plate 17 that is guided by the guide portion 16 and slides on the elongated hole 13 in the front-rear direction;
Limit switch 18 that turns on and off by pressing
It consists of The guide part 16 includes a stop wall 19 parallel to the front side 11 of the main case on the rear end 13a side of the elongated hole 13, and guide walls 21, 21 extending from both ends of the stop wall 19 into the elongated hole parallel to the side surface 20 of the main case. It extends toward the front end 13b side. The switch plate 17 has a horizontally elongated shape that fits between the left and right guide walls 21, 21, and is biased toward the stop wall 19 by a spring body 22. By providing the arc-shaped notches 23, 23, the front half of the elongated hole 13 is usually covered with the switch plate 17, and the circular rotating shaft insertion holes 24, 24 passing through the upper and lower cases 2a, 2b are opened. ing. Further, a limit switch 18 is provided close to the front of the reciprocating range of the switch plate 17, and as the switch plate 17 moves back and forth, the switch 1 is activated at the front edge 17b.
The degaussing signal generator 3
Regulates the timing of operation.

As shown in the block diagram of FIG. 3, the degaussing signal generator 3 boosts the voltage _V1 of the battery 25 by applying it to the DC-DC converter 26 via the limit switch 18, and then applies this output voltage _V2 to the switching circuit. 27. The switching circuit 27 is a transistor switch that is preset to turn on when the input voltage V ₂ reaches a set voltage V' ₂ of, for example, about 16V. Transfer voltage V′ ₂ . At the same time, by sending a signal from the input side of the switching circuit 27 to the control circuit 29 via the light emitting diode 30, the switching circuit 27 is opened and the DC/DC converter 26 and the capacitor 28 are completely separated, and the DC・DC
The output voltage V ₂ of the converter 26 is dropped to a voltage low enough to cause the light emitting diode 30 to emit light to indicate that the battery 25 is normal. Further, a self-excited oscillation circuit 31 that generates an alternating voltage having a peak value approximately proportional to the input voltage value is connected to both ends of the capacitor 28, like a push-pull circuit.
The oscillation circuit 31 starts oscillating at the same time as the voltage V' ₂ is transferred to the capacitor 28, but at this moment the current supply to the capacitor 28 is cut off, so the capacitor 28 continues to discharge and the voltage between its terminals drops, and the oscillation circuit 31 starts to oscillate. circuit 31
gives a damped alternating voltage V _{3 whose} peak value drops with a certain time constant. This voltage V ₃ is applied to the degaussing head 32 and converted into a damped alternating magnetic field. The degaussing head 32 has a coil 34 wound around the leg of a substantially U-shaped sintered ferrite or laminated iron core 33, and the tip thereof is covered with a protective piece 35 made of soft synthetic resin or the like. The protective piece 35 is fixedly disposed within the magnetic head insertion hole 37, with the tip 36 of the protective piece 35 aligned with the case front surface 11.

However, when demagnetizing the magnetic head 38 of the tape recorder 8 using the demagnetizer 1 according to the present invention,
As shown in FIG. 2a, the rotation shaft insertion holes 24, 2 are opened on the left and right sides of the upper surface of the main body case 2 for the rotation shafts 12, 12.
Set according to 4. When the playback switch of the tape recorder is pressed here, the magnetic head 38 comes out toward the degaussing head 32, presses the protective piece 35 at the tip of the degaussing head, and causes the entire main body case 2 to retreat. At this time, the switch plate 17 moves forward relative to the main body case 2 while compressing the spring body 22 as shown in FIG. 2b, and closes the contact 18a of the limit switch 18 with the front edge 17b. Then, the demagnetizing signal generator 3 operates to generate a demagnetizing signal to the demagnetizing head 32, thereby demagnetizing the magnetic head 38 that is in contact with the demagnetizing head 32.

When the magnetic head 38 is moved back after degaussing, the switch plate 17 is moved to the rotation axis 1 by the spring body 22.
2 is pressed and the main body case 2 is returned to the normal position shown in FIG.

The configurations of the switch section 4 and the degaussing signal generating section 3 are not limited to those described above, and can be modified as appropriate as long as they can generate a demagnetizing signal in conjunction with the back and forth movement of the main body case 2. For example, the positioning pin 9 of the tape recorder 8 and the capstan 1
0 can also be demagnetized by adding a demagnetizing head 32. In this case, since the distance between the capstan 10 and the demagnetizing head 32 increases with the demagnetizing operation, the demagnetizing signal generating section 3 does not need to generate an attenuation signal, and the circuit configuration is simplified.

As explained above, the present invention provides a demagnetizer that is set on the rotating shaft 12 in the cassette tape recorder 8.
The whole body is configured to be freely deflectable, and the degaussing head 32 is fixed to the magnetic head insertion window 37 of the main body case 2, and as the magnetic head 38 on the tape recorder 8 side enters, the degaussing head 32 and the main body are moved. When you push and move case 2, main case 2
A switch plate 17 provided therein is pressed against the rotary shaft 12 on the tape recorder 8 side, and the degaussing signal generator 3 is automatically operated via this switch plate 17. Therefore, unlike the conventional configuration in which the degaussing head moves backward within the main body case when pushed by the magnetic head, in the present invention, the degaussing signal generating section 3, specifically its signal generating circuit board 39, and the degaussing head 32 are Since both are fixed, it is possible to reliably prevent an accident of disconnection of the connecting wire 40 connecting these two 39 and 32.
It has the advantage of being durable for long-term use.
Further, since the demagnetizing head 32 is fixed to the main body case 2, even if the demagnetizing head 32 is pushed by the magnetic head 38 on the tape recorder 8 side, it will not tilt, and the demagnetizing head 32 and the magnetic head 38 will always be in contact with each other. Correct contact also allows the magnetic head 38 to be effectively demagnetized.

[Brief explanation of drawings]

1 to 3 show an example of the demagnetizer according to the present invention, FIG. 1 is an exploded perspective view showing the overall structure, FIGS. 2 a and b are explanatory views showing the operating situation,
FIG. 3 is a block diagram of the degaussing signal generator. FIG. 4 is a plan view of the conventional example with the upper case removed. 2... Main body case, 3... Degaussing signal generator, 4
... Switch part, 7 ... Notch, 12 ... Rotating shaft, 16 ... Guide part, 17 ... Switch plate, 18
...Limit switch, 22...Spring body, 13...
...Long hole, 32...Demagnetizing head.

Claims (1)

[Scope of utility model registration request] This demagnetizer is provided with a demagnetizing signal generating section 3 having a demagnetizing head 32 that generates an alternating magnetic field in the main body case 2, and is set on a rotating shaft 12 in a cassette type tape recorder 8 to demagnetize at least the magnetic head 38. , the rotation shaft insertion hole 24, and the positioning pin 9 on the lower wall side of the main body case 2 and the capstan 1.
0 is to be inserted at least in the extending direction of the magnetic head 38, so that the entire main body case 2 can be freely deflected in the tape recorder, and the magnetic head insertion window 3
The demagnetizing head 32 is fixed to the magnetic head 7, and as the magnetic head 38 enters, the main body case 2 is displaced from the normal position together with the demagnetizing head 32, and the switch plate 17 provided inside the main body case 2 rotates as described above. A demagnetizer characterized in that a demagnetizing signal generating section 3 is activated when pressed by a shaft 12.