Dynamic magnetic information storage or retrieval – Head mounting – For moving head into/out of transducing position
Reexamination Certificate
1998-07-31
2001-01-09
Renner, Craig A. (Department: 2754)
Dynamic magnetic information storage or retrieval
Head mounting
For moving head into/out of transducing position
C360S254200
Reexamination Certificate
active
06172856
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head transferring device of a hard disk drive and, more particularly, to a magnetic head transferring device of a hard disk drive having an improved structure for unlocking a magnetic head locked in a parking area.
2. Description of the Related Art
As shown in
FIG. 1
, a hard disk drive is composed of a hard disk
20
rotatably installed on a base
10
for recording and reproducing information and a magnetic head transferring device for moving a magnetic head
50
to a desired track position on the hard disk
20
to record and read information. Here, the surface of the hard disk
20
is divided into a recording area
22
in which information is recorded and a parking area
21
provided at the inner portion of the hard disk
20
where the magnetic head
50
is placed when the rotation of the hard disk
20
stops.
The magnetic head transferring device has a rotor
30
installed to be capable of pivoting around a pivot shaft
34
provided on the base
10
and on which the magnetic head
50
is mounted, a stator
40
for actuating the rotor
30
to pivot by an electromagnetic force, and a locking means for locking the rotor
30
after the magnetic head
50
is placed in the parking area
21
. The rotor
30
is composed of a suspension portion
31
for supporting the magnetic head
50
, a swing arm
32
installed to be capable of pivoting around the pivot shaft
34
via pivot bearings
34
a
, and a bobbin
33
around which a coil
35
for generating an electromagnetic force is wound. The stator
40
has a magnet
41
and a yoke
42
for forming a magnetic field. Thus, as an electromagnetic force is generated due to interaction between the magnetic field generated by the magnet
41
, the yoke
42
, and the current flowing in the coil
35
, the rotor
30
is caused to pivot in a direction according to Fleming's left-hand rule.
The locking means is composed of a damper
60
coupled to a protrusion
36
provided at an end of the bobbin
33
of the rotor
30
, a first magnetic member
61
which is bonded at an end of the damper
60
, and a second magnetic member
43
installed on the stator
40
. When the magnetic head
50
installed at the suspension portion
31
enters the parking area
21
of the hard disk
20
as the rotor
30
is pivoted, the first and second magnetic members
61
and
43
are attracted and stick to each other by a magnetic force, as shown in FIG.
1
. Thus, the rotor
30
remains in a locked state in which the first and second magnetic members
61
and
43
are stuck to each other, unless an electromagnetic force for pivoting the rotor
30
operates again.
Magnets can be used as the first and second magnetic members
61
and
43
. A normal metal piece capable of being magnetized by a magnetic force can also be used for at least one of the first and second magnetic members
61
and
43
. The first and second magnetic members
61
and
43
can be magnetized by a magnetic field formed by the magnet
41
and the yoke
42
.
To prevent the rotor
30
from being unlocked when a strong external impact is applied, an increase in the magnetic force is required for attracting the first and second magnetic members
61
and
43
. However, when a strong magnetic force is used, the unlocking of the rotor
30
is difficult.
Typically, in order to pivot the locked rotor
30
again, an electromagnetic force stronger than that of the coupling force between the first and second magnetic members
61
and
43
is applied to separate them. When the first and second magnetic members
61
and
43
are stuck to each other with a strong magnetic force, a separation force greater than the strong magnetic force, is required. When the first and second magnetic members
61
and
43
are separated by a strong separation force, the rotor
30
abruptly rotates such that the magnetic head quickly travels toward the outside edge of the hard disk, as if the rotor had received an external impact. The strong electromagnetic force continues to act on the rotor during at least part of the rotor's rotation, causing excessive rotation of the rotor. Thus, because the magnetic head
50
is moved too far out of the recording area
22
of the disk
20
, extra time is required to return the magnetic head
50
to the desired position, and moreover, the magnetic head
50
may be damaged by bumping against other elements.
Therefore, a smooth unlocking of the magnetic head, in spite of the increased coupling force between the first and second magnetic members
61
and
43
, is required.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide a magnetic head transferring device of a hard disk drive having an improved structure so that the rotor does not pivot excessively when unlocked although a large coupling force is used to lock the rotor.
Accordingly, to achieve the above objective, there is provided a magnetic head transferring device of a hard disk drive comprising: a rotor rotatably mounted on a base and having a magnetic head for recording/reproducing information on/from the hard disk situated near one end thereof; a stator installed on the base for actuating the rotor to move across a parking area and a recording area formed on the hard disk; first and second magnetic members respectively installed at one end of the rotor and the stator and magnetically coupled to one another when the magnetic head is positioned in the parking area of the hard disk so that the rotor is locked to not move; and a pushing unit for gradually pushing the rotor by pressing the same in a direction that the first and second magnetic members are separated during unlocking thereof.
It is preferable in the present invention that the pushing unit comprises: an electric heating plate heated by current applied from a predetermined power supply source; a bimetal member reversibly deformed by the heat transmitted from the heating plate; and a rod member having one end contacting the bimetal member and the other end contacting the rotor, for gradually pushing the rotor as the bimetal member is deformed.
REFERENCES:
patent: 4047484 (1977-09-01), Cole
patent: 5003422 (1991-03-01), Sun et al.
patent: 5084793 (1992-01-01), Ishida et al.
patent: 5448435 (1995-09-01), Nakazawa et al.
patent: 5528437 (1996-06-01), Mastache
patent: 5568333 (1996-10-01), Bang
patent: 5729405 (1998-03-01), Isomura et al.
patent: 5742455 (1998-04-01), Boutaghou
patent: 31 08 838 (1982-09-01), None
patent: 55-078870 (1980-06-01), None
patent: 60-147981 (1985-08-01), None
patent: 7-031118 (1995-01-01), None
Japanese Patent Abstract of 08-212729 by Ishizaki et al., Aug. 20, 1996.
Patent Abstracts of Japan vol. 009, No. 323 (P-414), Dec. 18, 1985 & JP 60 147981 A (Mitsubishi Denki KK) Aug. 5. 1985 *Abstract.
Renner Craig A.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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