Dynamic magnetic information storage or retrieval – Head mounting – For moving head into/out of transducing position
Reexamination Certificate
2000-03-13
2002-09-03
Heinz, A. J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
For moving head into/out of transducing position
Reexamination Certificate
active
06445548
ABSTRACT:
The present invention generally relates to an actuator arm adapted to drive a head in a disk apparatus, and more particularly, to a latch mechanism adapted to hold the actuator arm in a predetermined position during non-operation of the disk apparatus.
BACKGROUND OF THE INVENTION
A disk apparatus for recording and reproducing information to or from a disk medium must to avoid wear which results from contact between the head slider and the disk surface. Therefore, a contact-start-stop (CSS) system is employed in which, during non-operation of the disk apparatus, the head is in contact with the disk surface, and during operation of the disk apparatus, namely, during recording or reproducing operations, the head floats above the rotating disk surface.
In a disk apparatus employing the CSS system, the head slider includes a head element to record or reproduce information to or from a disk which floats away from the rotating disk surface during operation of the disk drive by receiving air flow generated by rotation of the disk. When information is recorded or reproduced, the head slider moves while floating above the rotating disk surface and is then placed over a predetermined track of the disk. When the disk apparatus is in the non-operating condition, the head slider is placed within the CSS zone provided on the disk surface. Moreover, when the disk apparatus is in the non-operating condition, since the disk is not rotating, air flow for floating the head slider is not generated and the head slider is in contact with the CSS zone.
If the disk apparatus receives a shock when the head slider is in contact with the CSS zone, the head slider may move to the data zone and cause damage, namely, a destruction of data or a disabling of the data reading or writing operation. In recent years, with reduction of size, such a disk apparatus has been used in portable devices such as note-sized personal computers. Such a disk apparatus is often placed in a condition where it may easily receive an external shock. Therefore, high durability against shock is one of the performance characteristics required for a disk apparatus.
Therefore, a latch mechanism has been provided so that the actuator is fixed in the stop position when the disk apparatus is in the non-operating condition. By providing the latch mechanism, if the disk apparatus receives a certain degree of shock, the head slider does not move to the data zone and thereby the disk and data can be protected.
FIGS.
1
(
a
) and
1
(
b
) illustrate a structure of the latch mechanism of the related art. A voice coil
51
is mounted at the rear end surface of an actuator
22
which supports a head slider
4
,. The voice coil
51
is placed within magnetic fields generated by an upper permanent magnet
54
provided at the lower surface of an upper yoke
52
, and a lower permanent magnet
55
provided at the upper surface of lower yoke
53
. A voice coil motor (VCM)
23
which rotates the actuator
22
includes the voice coil
51
, upper and lower yokes
52
,
53
and permanent magnets
54
,
55
or the like.
A latch magnet
11
is provided in the area outside the magnetic field of the rear end surface of the actuator
22
. Moreover, opposing dowels
12
are provided which sandwich the plane of motion of the latch magnet
11
. The dowels are located at the lower surface of upper yoke
52
and at the upper surface of the lower yoke
53
. The dowels
12
are generally formed by pressing the yokes
52
,
53
.
According to this structure, when the head slider
4
stops in a CSS zone
31
of a disk
1
, the latch magnet
11
is proximal to the dowels
12
and magnetic force attracts the latch magnet
11
toward the dowels
12
. As a result, a counterclockwise torque is generated in the actuator
22
and thereby the actuator
22
is energized or biased in the counterclockwise direction. Therefore, when the head slider
4
receives a shock when it is in contact with the CSS zone
31
, it is prevented from moving to data zone
32
.
In order to realize a highly reliable latch mechanism, the actuator
22
must be energized or biased toward the CSS zone
31
by an intensive torque. In the latch mechanism illustrated in
FIG. 1
, the magnetic force of latch magnet
11
must be intensified to attain a strong latch force. However, when the magnetic force of the latch magnet
11
is raised, a significant attracting force is generated between the dowels
12
and the latch magnet
11
even during seek operations, resulting in an influence on the seek control. As a result, the seek control becomes difficult and the processing speed is decreased. Moreover, when an intensified magnetic force of the latch magnet
11
is required, it also requires enlargement of the latch magnet
11
. Since the latch magnet
11
illustrated in
FIG. 1
is provided at the far end of the rotating shaft of the actuator
22
, enlargement of latch magnet
11
requires a large rotating inertia of the actuator
22
to release the latch. Thereby, the load on VCM
23
becomes large and power consumption also becomes large.
As a solution to the problems explained above, a latch mechanism utilizing a solenoid and a mechanical latch mechanism utilizing air pressure generated by rotation of the disk medium have been proposed, but these mechanisms require the addition of expensive parts, thereby increasing cost.
It is therefore a first object of the present invention to improve the shock resistance of a disk apparatus.
It is a second object of the present invention to provide a disk apparatus which assures high speed operation.
It is a third object of the present invention to provide a low cost disk apparatus.
It is a fourth object of the present invention to provide a latch mechanism having a simplified structure.
It is a fifth object of the present invention to provide a latch mechanism having a large latching force.
SUMMARY OF THE INVENTION
In a latch mechanism used for a disk apparatus of the present invention, a latch force is obtained from a latch magnet attached to an actuator. The latch magnet passes through a magnetic field generated by two permanent magnets of a voice coil motor (VCM), with a rotating or swinging shaft of the actuator defining a center of rotation. According to this structure, a magnetic force in the rotating direction of the actuator can be generated between the latch magnet and the permanent magnets of the VCM when the actuator is in certain locations. The magnetic force working on the permanent magnets is higher than the magnetic force working between the metal piece and magnet of the related art. Therefore, an intensive latch force can be obtained from this magnetic force to improve the shock resistance of the disk apparatus. In addition, the latch mechanism has a simplified structure which does not require additional parts and therefore a low cost disk apparatus can be realized. Moreover, the latch magnet can be located proximal to the rotating shaft of the actuator, thereby decreasing the rotational inertia of the actuator. Accordingly, the load required for the VCM drive the actuator is alleviated to realize reduction of power consumption and high speed seeking.
Moreover, when the direction of the magnetic flux of the latch magnet is parallel to the direction of the magnetic flux generated by the permanent magnets of the VCM, and the head slider is resting on the CSS zone, it is preferable that the latch magnet be placed at least partially outside of the magnetic field of the permanent magnets. According to this structure, when the disk is in the non-operating condition and a latching of the actuator is required, a magnetic force in the direction of rotation of the actuator is generated between the latch magnet and the permanent magnets, and an intensive latch force can be obtained from this lateral magnetic force.
Moreover, when the head slider is located at a position furthest from the CSS zone in the movable range of the actuator, it is preferable for the latch magnet to be placed in the magnetic field of the permanent magnets. According to this structure, a ma
Oikawa Satoshi
Otsuka Toshiaki
Sasaki Tsutomu
Greer, Burns & Crain LTD
Heinz A. J.
LandOfFree
Disk apparatus having a latch mechanism for holding the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Disk apparatus having a latch mechanism for holding the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disk apparatus having a latch mechanism for holding the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2895566