JPH056729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cassette type degaussing device, which is capable of demagnetizing a magnetic head and erasing a magnetic tape.

Cassette-type demagnetizing devices are widely used as devices that can easily demagnetize the magnetic heads of recording and reproducing devices. This type of cassette type degaussing device is constructed by housing a degaussing head and a degaussing circuit in a main body case, and the magnetic head on the deck side is inserted into the case through the magnetic head insertion opening provided at the front of the main body case. The front surface thereof is brought into contact with the front surface of the demagnetizing head, and an alternating gradually decreasing magnetic field is generated in the demagnetizing head to perform demagnetization. The present invention has been made for the purpose of providing a cassette type degaussing device of this type, which is capable of degaussing the magnetic head as well as erasing signals recorded on the magnetic tape. In the cassette type demagnetizing device, an alternating gradual current oscillation circuit and an alternating continuous current oscillation circuit are arranged in the main body case, and both circuits are selectively installed in the demagnetizing head part. By providing a changeover switch section for connection to the magnetic tape, the degaussing head can be operated to demagnetize the magnetic head and erase signals recorded on the magnetic tape. This makes it easy to partially erase signals recorded on a magnetic tape. In addition, by detachably attaching the degaussing head to the attachment part formed on the front of the main body case, it is possible to easily degauss hard-to-reach places such as capstans, and it is also possible to erase magnetic tapes. When performing degaussing, at least the front part of the degaussing head is made to protrude outside the main case so that it can come into contact with the magnetic tape to be erased, and the magnetic tape is moved using a winder or other means to record on the magnetic tape. This allows the signal to be easily erased. Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a cassette-type degaussing device according to the present invention, in which 1 is a main case consisting of an upper case 2 and a lower case 3, and a demagnetizing head 4 is installed in the center of the front part. A mounting part 5 for removably mounting and storing is provided in a recessed manner, and by taking out the degaussing head part 4 from this mounting part 5, the front surface thereof can be freely projected from the front surface of the main body case 1. 6, 6 and 7, 7 are pinch roller insertion ports and capstan insertion ports formed on both sides of the mounting portion 5, and 38, 38 are tape path portions.
Reference numeral 8 denotes a wiring board disposed within the main body case 1, and an alternating continuous current oscillation circuit and an alternating gradual decreasing current oscillation circuit, which will be described later, are wired to the board 8. Reference numeral 9 is a power battery, and reference numerals 10 and 10 are hubs.

Reference numeral 11 denotes a long strip-shaped connection cord that connects the degaussing head section 4 to the alternating continuous current oscillation circuit and the alternating gradually decreasing current oscillation circuit, and conductive wires 12a and 12b are wired inside the cord (see Fig. 4). reference).
Reference numeral 14 denotes a storage groove for the connection cord 11, which is recessed around the main body case 1 and continuous with the mounting portion 5. The length of the connection cord 11 is equal to the length of the storage groove 14, and is wound and stored in the storage groove 14. Reference numeral 141 denotes a curved surface formed at a corner of the storage groove 14, and is formed to prevent the cord 11 from being bent and the conductive wire 12 from being disconnected when the connection cord 11 is wound. 14
2 and 142 are cut grooves formed in a tapered shape on both sides of the storage groove 14, and both ends of the connection cord 11 are fitted into the cut grooves 142 and 142 to be stored therein.
Reference numeral 15 denotes a locking rod that is installed upright on the storage groove 14 of the upper case 2, and 16 is a locking hole formed in the connection cord 11. When the connection cord 11 is wound and stored in the storage groove 14, The locking hole 16 is inserted into the locking rod 15. Numeral 17 is a substantially U-shaped locking body whose thickness is the same as that of the main case 1, and is pushed onto the connection cord 11 wound around the main case 1 so that the cord 11 is inserted into the storage groove 14. It is attached elastically so that it does not come off. 18 is a positioning recess formed in the inner surface of the upper plate of the locking body 17,
The locking body 17 is fitted onto the top of the locking rod 15 with the locking body 17 attached.

5 and 6 show details of the degaussing head section 4, in which numeral 41 indicates an upper box 42 and a lower box 4.
The degaussing head 44 is housed inside the box-shaped unit with its front part slightly protruding. 45 is a leaf spring, and the back surface of the demagnetizing head 44 is supported by the spring 45 so as to be able to move forward and backward. 46 is a rib that supports both ends of the leaf spring 45. 47 is a limit switch disposed behind the degaussing head 44, and its lever 48 is in contact with the back surface of the degaussing head 44.
When the degaussing head 44 retreats, the lever 48 is turned on. Reference numeral 49 denotes locking bodies protruding from both sides of the lower box 43, and the locking bodies 49 have elasticity.
It can be fitted and locked to a part of the object to be erased, and
Grooves 19, 1 formed on both side walls of the mounting portion 5
9, the demagnetizing head section 4 is removably mounted on the mounting section 5.

Reference numeral 20 indicates a sliding switch button slidably disposed on the upper surface of the upper box 42, and 21 indicates the button 2.
It is a slider disposed in the lower box 43 below 0,
The upper end of the stand rod 22 erected on the upper surface of the slider 21 is connected to a locking portion 23 provided on the lower surface of the button 20.
It is locked in the locking hole 24 of. 25 is a fitting opening into which the button 20 is slidably fitted. Variable contacts 26a and 26b are provided at both ends of the slider 21, and when the button 20 is slid with a fingertip, the slider 21
slides together with this, and the variable contacts 26a, 26
b is displaced (see the chain line a in Figure 7). Fixed contacts 27 and 28 are arranged in contact with one side of the slider 21, and when the button 20 is slid backward, the variable contact 26a comes into contact with the fixed contacts 27 and 28. The contacts 27 and 28 are electrically connected to the conductive wire 12a leading to the wiring board 8, and the degaussing circuit is closed as will be described in detail later.
4 can produce an alternating tapering magnetic field. Furthermore, when the button 20 is slid forward, the variable contact 26b contacts the fixed contacts 27 and 28 and is electrically connected to the conductive wire 12b leading to the wiring board 8, and the erasing circuit is closed, causing the degaussing head 44 to receive a continuous alternating magnetic field. occurs. That is, the button 20, the slider 21, and each contact 26 to 28
etc. constitute a changeover switch section 29 for selectively connecting the degaussing circuit and the erasing circuit to the degaussing head section 4.

FIG. 9 is a circuit block diagram of this embodiment.
DC booster circuit section 30, switching circuit section 31,
A well-known degaussing circuit 34 consisting of a capacitor C and an oscillation circuit section 32 is configured, and the oscillation circuit section 32
Inside, a circuit section capable of oscillating a high frequency that can satisfactorily erase a recorded tape and a circuit section that can oscillate a frequency suitable for satisfactorily demagnetizing a magnetic head are selectively provided. Further, the oscillation frequency of the oscillation circuit section 32 can be selectively varied by switching the slide button 20, and when the slide button 20 is moved in the direction of the arrow a, the circuit 33 is closed, creating a high-frequency alternation that enables good erasure of the recorded tape. A continuous current is supplied to the degaussing head 44, and when it is moved in the direction of arrow b, an alternating and gradually decreasing current can be supplied to the degaussing head 44, which can effectively demagnetize the magnetized head. Reference numeral 48 denotes a lever of a limit switch 47 that is linked to the protrusion of the degaussing head 44, and is turned on when the degaussing head 44 retreats.

FIG. 8a shows how the magnetic tape 36 stored in the cassette case 35 is being erased. case 35
It is attached to. 37, 37 are hubs provided in the case 5. Of course, the elastic locking body 49 may not be used and it may be supported by hand as shown in FIG. 8b. This device has the above-mentioned configuration, and its handling operation will be explained next.

When demagnetizing the magnetic head H of the recording/playback device, attach the demagnetizing head section 4 to the mounting section 5, slide the switch button 20 backward, that is, move it in the direction of the arrow b in Fig. 9, and start the alternating gradually decreasing current oscillation. Configure the circuit. Next, remove the main case 1 (not shown)
Attach it to the cassette mounting part of the deck and operate the play button on the deck side. Then, the magnetic head H moves forward and comes into contact with the front surface of the demagnetizing head 44.
is pushed back by this and the limit switch 47
The lever 48 is turned to the on side. Then, the terminal voltage of the battery 9 is boosted by the booster circuit 30 and the capacitor C is charged. When the capacitor C is charged to a predetermined voltage, the switching circuit 31 is activated and the oscillation circuit section 32 is activated by the discharge current of the capacitor C.
oscillates, producing an alternating gradually decreasing magnetic field in the demagnetizing head 44, thereby demagnetizing the magnetic head H.

Next, when erasing the signals recorded on the magnetic tape 6 housed in the cassette case 35, remove the degaussing head section 4 from the mounting section 5, and while stretching the connection cord 11, insert the front side of the degaussing head section 4 into the main body case. 1 and slide the switch button 20 forward, that is, move it in the direction of arrow a in FIG. Then, the oscillation circuit section 32 that oscillates high frequency is directly connected to the power supply battery 9 without going through the booster circuit 30 or the switching circuit 31, and the oscillation circuit section 32 oscillates to generate an alternating continuous magnetic field in the demagnetized head 44. Therefore, the front side of the degaussing head 44 is inserted into the cassette case 35, and the magnetic tape 36 is inserted into the cassette case 35.
The locking body 49 is engaged with the tape path portion 38 of the magnetic tape 36, the degaussing head 44 is brought into contact with the magnetic tape 36, and the tape 36 is fed by rotating the hub 37 with a suitable means such as a tape winder. 3
The signals recorded on the magnetic tape 6 are erased as the magnetic tape 36 is fed (see FIG. 8). Such erasing of the magnetic tape 36 is advantageous when it is desired to partially erase the signals recorded on the magnetic tape 36 or when it is desired to erase quickly using a tape winder or the like. Further, according to the present device, the magnetic head H can be demagnetized with the demagnetizing head section 4 taken out from the mounting section 5. In other words, in this case, slide the switch button 20 backwards to close the variable contact 2.
6a against the fixed contacts 27 and 28, hold the demagnetizing head part 4 in your hand and press it against the front surface of the magnetic head H to be demagnetized, and turn the lever 48 to the on side to demagnetize in the same way as above. An alternating gradually decreasing magnetic field is generated in the head 44, and the magnetic head H is demagnetized. According to such a degaussing method, it is possible to demagnetize the magnetic head of a deck where the main body case 1 cannot be cassetted, and demagnetize the capstan and the like.

10 to 14 show another embodiment of the present invention, in which 51 is a main case having the same size and shape as a Phillips-type compact cassette consisting of an upper case 52 and a lower case 53; 51
A demagnetizing head section 55, which includes the demagnetizing head 44 and the like, is housed in a mounting section 54 provided at the center of the front portion so as to be detachable by means described later. 56 is a magnetic head insertion port, 57, 57 is a pinch roller insertion port,
Reference numerals 58 and 58 are capstan insertion openings, and 59 is a wire spring that resiliently supports the degaussing head portion 55 so as to be able to move forward and backward. Reference numeral 60 denotes a rod-shaped protrusion that projects horizontally toward the rear on the back surface of the degaussing head section 55;
A variable mounting portion 61 made of a conductive film is provided at the center of the holder. 62, 62 and 63, 63 are fixed contacts arranged so as to come into contact with the protrusion 60, and a wiring board 7 on which a degaussing circuit and an erasing circuit are wired.
Connected to 0. Reference numeral 64 denotes an operator erected on the degaussing head 55, the top of which slightly protrudes from an elongated hole 65 vertically formed in the center of the front part of the upper case 52. The variable contact 61 is normally in the solid line position in FIG. 13, and the fixed contacts 62, 62 and 63, 63 are open, but when the demagnetizing head 44 is pushed back by the magnetic head H, The fixed contacts 62, 62 come into contact with the variable contact 61, and both contacts 62, 62 are electrically connected to generate an alternating gradually decreasing magnetic field in the degaussing head 44 (13th
(See the dashed line in the figure). Furthermore, when the top of the operator 64 is operated with a fingertip to slide the degaussing head 55 forward, the front surface of the degaussing head 55 is attached to the main body case 51.
The variable contact 61 protrudes slightly from the front of the
is in contact with the fixed contacts 63, 63, and both contacts 6
3 and 63 are electrically connected to generate an alternating magnetic field in the demagnetizing head 44 (see the chain line in FIG. 13). In this state, the front portion of the degaussing head 44 slightly protrudes from the magnetic head insertion opening 56. If the front part of the degaussing head 44 is made to protrude from the insertion opening 56 and enter the cassette case 35 in this way, the front part can be brought into contact with the magnetic tape 36 (see the chain line in FIGS. 13 and 14). reference). That is, the protrusion 60, the operating element 64, and the contacts 61 to 63 constitute a changeover switch section 69 for selectively connecting the degaussing circuit and the erasing circuit to the degaussing head section 55. 66,
66 is a small positioning projection for holding the operator 64 in the forward position; 67 is a tape guiding roller disposed inside the cassette case 35; and 68, 68 are ribs for guiding the degaussing head 55 forward and backward. . FIG. 15 shows an electric circuit, which is different from the electric circuit of the first embodiment in that the limit switch 47 is not configured and that the changeover switch section 2 is not provided with the limit switch 47.
The difference is that a changeover switch section 69 is provided instead of the switch section 9.

When demagnetizing the magnetic head H in the above configuration, by setting the case 51 on the deck and operating the play button, the demagnetizing head section 55 is pushed by the magnetic head H and resists the spring force of the wire spring 59. The variable contact 61 comes into contact with the fixed contacts 62, 62, and the demagnetizing circuit 34 is closed. An alternating gradually decreasing magnetic field is generated in the demagnetizing head 44, and the magnetic head H is demagnetized. When erasing signals recorded on the magnetic tape 36 housed in the cassette case 35, the operator 64 is slid forward to cause the front part of the degaussing head 44 to protrude from the insertion slot 56. In this state, the variable contact 61 is connected to the fixed contacts 63, 63.
The oscillation circuit section 32 as an erasing circuit oscillates to generate an alternating gradually decreasing magnetic field in the demagnetizing head 44.
Then, insert the front part of the degaussing head 44 into the cassette case 3.
5 and come into contact with the magnetic tape 36,
If the hub 37 is rotated by an appropriate means to feed the tape 36, the signals recorded on the tape 36 will be erased. As described above, only the front portion of the degaussing head 44 may be made to protrude outside the main body case 51.

FIG. 16 shows yet another embodiment of the present invention, in which a multi-stage switching section 72 as a switching section is provided on the main surface of a main body case 71. As shown in FIG. 17, the multi-stage switching section 72 is capable of converting the oscillation frequency from several hundred Hz to several MHz, and when set to a scale section with a relatively low frequency, it forms an alternating gradually decreasing current circuit, and the high frequency scale When set in the section, an alternating continuous current circuit is formed. By providing the multi-stage switching section 72 in this manner, it is possible to select a frequency that matches the degree of magnetization of the object to be demagnetized, for example, a magnetic head, and not only can better demagnetization be performed, but also when erasing the recording on the tape. It is possible to appropriately select the optimum frequency that matches the winding speed of the wander, etc., and the erasing effect is improved.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and that, for example, the structure of the degaussing head section and the changeover switch section, the means for attaching and detaching the demagnetizing head section to the attachment section, etc., can be considered in various ways other than the above-mentioned embodiments. stomach. Furthermore, the main body case can also be applied to those having various shapes and structures, such as a Phillips-type compact cassette or a micro cassette.

As explained above, according to the cassette type degaussing device according to the present invention, by operating the changeover switch section 29, the degaussing head section 4 can demagnetize the magnetic head H by using a part of the well-known degaussing circuit. Signals recorded on the magnetic tape 36 can be erased. Furthermore, since the degaussing head section 4 is detachably attached to the mounting section 5 of the main body case 1, the front part of the demagnetizing head 44 can be projected from the main body case 1 and entered into the cassette case 35, and the magnetic field stored therein can be removed. The tape 36 can be easily erased, and in particular, there is an advantage that partial erasure of signals recorded on the magnetic tape 36 can be easily and accurately performed.

[Brief explanation of the drawing]

The figure shows an embodiment of the present invention.
The figure is a perspective view of the cassette type degaussing device, Figure 2 is a plan view, Figure 3 is a side view, Figure 4 is a partial sectional view, and Figure 5
The figure is an exploded perspective view of the degaussing head, Figure 6 is a plan view, Figures 7a and b are partial sectional views, Figure 8 is a plan view during handling, Figure 9 is an electrical circuit diagram, and Figure 10. 11 is a plan view, FIG. 12 is a partially exploded perspective view, FIG. 13 is a partial plan view, FIG. 14 is a partial sectional view, and FIG. 15 is an electric circuit. 16 and 17 are perspective views and plan views of still other embodiments. 1, 51... Main body case, 4, 55... Demagnetizing head section, 5, 54... Mounting section, 29, 69, 72
...changeover switch section.

Claims (1)

[Scope of Claims] 1. A degaussing head section 4 is housed in the front part of the main body case 1 so that its front surface can freely protrude from the front surface of the main body case 1, and an alternating gradually decreasing current oscillation circuit 34 and an alternating current oscillation circuit 34 are connected in the main body case 1. A changeover switch section 2 is provided with a current oscillation circuit 32 and selectively connects both circuits 34 and 32 to the degaussing head section 4.
A cassette type degaussing device comprising: 9. 2. The cassette-type demagnetizing device according to claim 1, wherein the demagnetizing head section 4 is detachably mounted on a mounting section 5 formed in the front part of the main body case 1.