JPS59213019A - Auto tracking mechanism for magnetic recording and reproducing apparatus - Google Patents

Abstract

PURPOSE:To generate no variation in a projecting quantity of a magnetic head even at the time of tracking by constituting an approximate linear mechanism of a pair of levers placed in parallel roughly, bending the lever by a driving means, and moving linearly the magnetic head in the track width direction of a recording medium. CONSTITUTION:In case when a tracking controlling track 48 is shifted and runs due to generation of waving of a magnetic tape 42, one of output values from a reproducing error signal detecting amplifier becomes small, the other becomes large, and an output value of a differential amplifier is varied to a minus side. As a result, a locker arm 66 is rotated, a magnetic head 40 moves together with a moving base 28, and a signal track follows up by a shift quantity of the tracking controlling track 48. When the magnetic head 40 moves, the levers 16, 17 constitute an approximate linear mechanism, respectively, therefore, the middle part moves linearly in the longitudinal right angle direction of the levers 16, 17, and since this linear moving direction is in parallel to the surface of the magnetic tape 42, a space between the magnetic tape 42 and the magnetic head 40 is invariable, and no detecting error is generated.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is used in a magnetic recording/reproducing device using a magnetic tape or the like. This invention relates to an auto-docking mechanism for recording flf raw equipment.

[Background Art] In a cheap recorder using a magnetic tape, the magnetic tape moves in the longitudinal direction and moves relative to the magnetic head during recording and reproduction by the magnetic head.

When this magnetic tape is moved, a so-called waving phenomenon occurs in which the tape moves with slight fluctuations in the width direction of the tape relative to the magnetic head, so a guide or the like is provided to suppress this phenomenon.

However, in the multitrack or PCM recording system in which recording and playback are performed using digital signals, a large number of signal tracks are formed parallel to each other in the tape width direction, and a large number of divided heads are formed in the magnetic head corresponding to these trunks. has been done.

Therefore, tracking errors may occur due to minute waving of the magnetic tape, making it difficult to obtain accurate reproduced signal information.

For this reason, conventionally, a tiger-king mechanism has been proposed in which a magnetic head is attached to the tip of a cantilevered arm and the cantilevered arm is swung by the driving force of a motor.
82.2). However, in this tracking mechanism, since the head is attached to the tip of the cantilever arm, vibrations from the outside are easily transmitted. Also to magnetism.
By attaching the RAD to the tips of two parallel tracking mechanisms, the magnetic head can move parallel to the magnetic tape, but when the arm rotates, the magnetic head moves back and forth with respect to the track recording surface of the magnetic tape. This changes the amount of protrusion of the front and rear ends, making it impossible to obtain a stable reproduction signal.

[Object of the Invention] Taking the above-mentioned facts into account, the present invention aims to provide an auto-tracking mechanism for a magnetic recording/reproducing device in which no change occurs in the amount of protrusion of the magnetic head during tracking (even during tracking).

[Structure of the Invention] In the auto-tracking mechanism for magnetic recording and reproducing equipment according to the present invention, a pair of bases disposed substantially parallel to each other are connected at once by a connecting member, and the other end is attached to the base to form an approximate linear mechanism. The magnetic head attached to the connecting member is moved linearly in the track width direction of the recording medium by bending the lever by the driving means.

[Embodiment of the Invention] As shown in Fig. 1.2, a pair of blocks 12 are fixed to the base plate 10 at a predetermined distance apart with screws 14, and these blocks 12111fl are connected to each other. Approximately parallel levers 16, 17 are provided. The bases 16A and 16B and 17A and 17B, which are both ends of these levers 16 and 17, are substantially parallel in the free state,
One end of these bases is inserted into a slit 18 formed in the block 12 and then fixed to the block 12 by means such as a screw 20 passing through in the thickness direction.

Between the other ends of these lever bases 16A and 16B and 17
The other 5 parts of A and 17B are integrally connected by connecting members 16C and 17C, respectively.

The connecting members 16c, 17c are therefore arranged obliquely relative to their respective ends, and the levers 16, 17 constitute a Watt's approximate linear movement mechanism. Therefore, as shown in FIG. 3, when the levers 16, 17 change from the free state shown by the solid line to the deflected state shown by the imaginary line, the connecting member 16c
, 17C, the φ points 16D, 17D (*1) move approximately linearly in a direction perpendicular to the base of the lever.

The lever bases 16A, 16B, 17A, and 17B may be made of any flexible material such as metal or synthetic resin, and the connecting members 16c and 17c may be made of steel plates, but may be made of the same material as the lever base. .

Each of these connecting members 16c and 17c is provided with a pair of flanges 22, 24 bent at right angles from both ends in the width direction. A pin 26.27 passes through each of these flanges 22.24. The tip of the pin 26 further passes through a circular hole 29A of the mounting base 28, and an E-ring 26A is attached to the tip. In addition, the tip of the pin 27 passes through the long holes 2 and 9B of the mounting base 28, and the E-ring 27 is attached to the tip.
A is attached, and the longitudinal direction of this elongated hole 29B is perpendicular to the longitudinal direction of the lever 16.17.

Therefore, when the levers 16, 17 are bent, the movable table 28 moves linearly in a direction perpendicular to the longitudinal direction of the levers 16, 17 when they are at rest. In this case 1 hole 2
9B is the lever 16.17 when the lever 16.17 is bent.
17 interval changes are absorbed.

Guide V-grooves 30 are formed along the longitudinal direction at both widthwise ends of the movable table 28 . Projections 34 projecting from guide posts 32 and 33 fixed to the base plate IO are inserted into these V-grooves 30, and these projections 34 are preferably pressed into the V-grooves 30 by a biasing force. This moves the moving table 28 to the lever 16.17.
An auxiliary guide means is configured to move the guide straight in a direction perpendicular to the direction.

An upright plate 36 projects at right angles from one longitudinal end of the movable table 28 . Case 3 fixed to this standing plate 36
A magnetic helad 40 is housed within the 8. The top surface of this magnetic helad 40 is the magnetic tape 4 shown by the Soho line in FIG.
It corresponds to 2. Therefore, this magnetic head 40
When the levers 16 and 17 are bent by elastic deformation together with the movable stage 28, they move linearly in the direction perpendicular to the longitudinal direction of the magnetic tape 42.

In FIG. 4, a plurality of divided heads attached to the magnetic head 40 are shown corresponding to the magnetic tape 42. As shown in FIG. That is, a plurality of magnetic tracks are formed on the magnetic tape 42 along the longitudinal direction of the tape, and these tracks extend from the end in the width direction of the tape to the running control track 44.
, signal tracks 46a, 46b, e...46(n-2)
, 46(n-1'), 46n, and a tracking control track 48.

The travel control trunk 44 is formed by a split head 50 for recording side travel control signals, and is detected and output by a playback side travel control split head 52. Similarly, signal tracks 46A, 46B, 46 (n-2), 46
('n-1), 46n is a recording signal division head 54a
, 54b fist・e54 (n-2), 54 (n-1), 5
4ni, and the reproduction signal dividing head 56a
, 56b-・-56 ('n-2), 56 (n-1),
56n. Further, the trunking control track 48 is formed by the recording side trunking control dividing head 58, and the reproduction side tracking control dividing head 6o, 62 forms the track 48.
Detection is performed in increments of 1/2 of the width of .

The moving table 28 shown in FIG. 1.2 has a long hole 64 formed on the opposite side of the installation plate 36 in a direction perpendicular to the long hole 29B.
After the mounting pin 68 protruding from one end of the rocker arm 66 is inserted, the E-ring 68A is attached. The intermediate portion of this rocker arm 66 near the pin 68 is connected to the base plate 10 by a pin 72 and an E ring 72A.
A piezoelectric ceramic 4-tube bimorph 74 is mounted on the other end.
One end of is clamped. The other end of this piezoelectric ceramic bimorph 74 is crimped via a holder 8o to a block 78 fixed to the base plate 6. The rocker arms 6, 6 are formed so that the length from the intermediate pin 72 to the piezoelectric ceramic bimorph 74 is smaller than the length from the pin 68 to the piezoelectric ceramic bimorph 74, so that the displacement force of the piezoelectric ceramic 4a is increased and transmitted. It has become.

As shown in FIG. 5, the piezoelectric ceramic bimorph 74 has a cantilever shape with a wall thickness of t and an arm length, and when connected to a power source 82 and a voltage is applied, it deforms due to crystal strain and causes flexure. , the movable table 28 is driven via the rocker arm 66. Therefore, by adjusting this applied voltage, the amount of displacement of the movable table 28 can be adjusted, and by reversing the direction of the applied voltage, deflection occurs in the opposite direction.

As shown in FIG. 6, the applied voltage E port of the piezoelectric ceramic bimorph 74 and the displacement amount Xp in sentence length from the fixed end
There is a linear relationship between the applied voltage Eport and the driving force Fgf as shown in FIG. A similar linear relationship occurs between the applied voltage and the displacement of the magnetic head I''40 to which the displacement of the piezoelectric ceramic bimorph is transmitted.

FIG. 9 shows a circuit diagram for controlling a piezoelectric ceramic bimorph as an actuator. A split head 6o for reproduction side tracking control shown in FIG.
The detection signal from 62 is transmitted to reproduction error signal detection amplifiers 84 and 8.
5 to reproduction error signal calibrators 86 and 87;
The calibrators 86 and 87 include band pass filters 8 and 89 for reproduced error signals, rectifiers 9o and 91, a low pass filter 92,
93 and is amplified by a differential amplifier 94 before being supplied to the piezoelectric ceramic bimorph 74.

Therefore, in this control circuit, if the calibrators 86 and 87 are calibrated in advance so that equal outputs are output when equal detection signals are obtained from the reproduction side tracking control split heads 60 and 62, the tracking control track 48 is the fourth
When the detected values from the split hendron 0.62 for tracking control on the playback side differ from each other in the magnetic tape width direction from the state shown in the figure, an output value proportional to this is supplied to the piezoelectric ceramic/input immorph 74 to perform trunking. A voltage can be applied according to the deviation.

Next, the operation of this embodiment will be explained.

When the magnetic tape 42 is traveling straight without causing any waving, the detection signals from the split Hentro 0.62 for trunking control on the playback side are equal, so the piezoelectric ceramic bimorph 74 does not displace and the lever 16. 1
7 and its elasticity maintain it in the neutral position, that is, the state shown in FIG. As a result, the reproduction signal division 56A,
58B etc. are accurately placed 6 in the signal trunks 46A and 46B, respectively, to enable accurate signal reproduction.

Next, for example, if the trunking control track 48 runs deviated in the direction C in FIG. 4 due to waving in the magnetic tape 42, the output value from the reproduction error signal detection amplifier 84 in FIG. , the output value of the reproduction error signal detection amplifier 85 increases, and the output value of the differential amplifier 94 changes to the negative side. This output value is therefore applied to the terminals of the piezoelectric ceramic RI/haymorph 74, which deforms as shown in FIG. 5 and causes the rocker arm 66 to rotate. As a result, the magnetic head 40 moves together with the moving table 28, and the signal tracks 46a, 46b, . . . , 46 (n-2
), 46 (n-1), and 46n follow the amount of deviation of the trunk 48 for controlling the tiger and king. Lever 16.
When the applied voltage from the differential amplifier 94 is removed, the piezoelectric ceramic 4 17 returns to its neutral state with its elasticity as the deflection of the piezoelectric ceramic 4 74 is removed. Conversely, tracking control trunk 4
When moving in the 8th or 4th direction, the reproduced signal dividing heads 56A, 56B also move upward following the signal tracks 46a, 46b.

In this way 1. Even when the magnetic tape 42 is waving in any direction, the reproduction signal dividing layer is always placed on the signal track, making it possible to detect a suitable signal.

When the magnetic head 40 is moved like this, the levers 16 and 17
Since each constitutes an approximate linear mechanism, the intermediate portion moves linearly in the direction perpendicular to the length of the levers 16 and 17, and since this linear movement direction is parallel to the surface of the magnetic tape 42, the magnetic tape 42 The distance between the magnetic head 40 and the magnetic head 40 remains unchanged, and no detection error occurs.

Particularly in this embodiment, since the movable table 28 is guided by the protrusion 34 of the guide boss 132 so as to move straight, the operation is stable. However, if the movement range of the magnetic head 40 is narrow, the guide posts 32 and 33 may be omitted and the magnetic head 40
It is also possible to support the magnetic head 40 only by the levers 16 and 17, and in some cases, the magnetic head 40 can be moved straight by using only one lever 16 and 17. Further, in the above embodiment, the lever bases 16A and 16B and 17A and 17B are each of equal length, but they may have different lengths, and furthermore, the lever bases 16A and 16B and 17A and 17B may have different lengths. It may be located at any position on the members 16c, 17C.

Note that in this embodiment, the magnetic head 40 and the lever 16
, 17, and the damping constant C of the V-groove guide, in order to suppress the resonant frequency fO and the resonance strength Q in the frequency-amplitude characteristic curve. A suitable structure is one in which a viscoelastic material such as the above is applied and dumped.

Although the second embodiment shows a structure in which the present invention is applied to a magnetic recording and reproducing device that uses a magnetic tape as a recording medium, the present invention can also be applied to a magnetic recording and reproducing device that uses other magnetic recording and reproducing media such as a floppy disk. is also applicable.

In the above embodiment, a piezoelectric ceramic bimorph is used as the drive means, so it is small and there is no dead zone when using a motor, etc. However, if necessary, a drive means such as a rotary motor or a linear motor can also be used. Applicable.

[Effects of the Invention] As described above, in the auto-tracking mechanism for magnetic recording and reproducing equipment according to the present invention, an approximate linear mechanism is configured by a pair of levers that are mutually arranged in approximately W rows, and the driving means drives the levers. Since the magnetic head is moved by bending the magnetic head, the magnetic head can be moved linearly in the track width direction of the recording medium, which has an excellent effect of achieving uniform signal detection with no change in the amount of magnetic protrusion 71' for DI performance. has.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the auto-tracking mechanism for magnetic recording and reproducing equipment according to the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 is a plan view showing the moving state of the lever. Figure 4 is an enlarged view showing the correspondence between the magnetic tape and the divided hent.
Fig. 5 is an explanatory diagram showing the deformation state of the piezoelectric ceramic bimorph, Fig. 614 is a diagram showing the relationship between the applied voltage of the piezoelectric ceramic bimorph and the amount of displacement, and Fig. 7 is a diagram showing the relationship between the applied voltage and the driving force of the piezoelectric ceramic bimorph. Line 1Δ showing the relationship:
FIG. 58 is a diagram showing the relationship between the applied voltage of the piezoelectric ceramic bimorph and the amount of displacement of the magnetic head in this example, and FIG. 9 is a control circuit diagram of the piezoelectric ceramic bimorph. 1o---Base plate, 16.17... Lever, 16A, 16B, 17A, 17B... Base. 16C117C...Connecting member. 40--Magnetic head, 42-Magnetic tape. 60... Split gear for playback tracking control 62.
... Split head for playback side dragging control Patent applicant Trio Co., Ltd.

Claims (1)

[Claims] (1) a lever comprising a pair of bases disposed substantially parallel to 'M and a connecting member connecting one ends of these bases, the other ends of the pair of bases being respectively attached to the base;
a magnetic head attached to the coupling member of the lever;
An automatic tracking mechanism for a magnetic recording rereading device, comprising: a drive means for bending the lever to move the magnetic hent in the track width direction of a magnetic recording medium.