Dynamic magnetic information storage or retrieval – Head mounting – For moving head into/out of transducing position
Reexamination Certificate
1994-06-29
2001-03-06
Letscher, George J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
For moving head into/out of transducing position
C360S256200, C360S075000
Reexamination Certificate
active
06198604
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an actuator unlocking apparatus and a method of releasing an actuator from magnetic attraction during power-on operation, in a disk storage apparatus. An actuator for moving a transducer head on a disk storage medium is locked by a magnetic locking apparatus to prevent the actuator and the disk storage medium from being damaged by unintentional movement of them when the disk storage apparatus is not powered. This invention relates to an improved method of and apparatus for releasing an actuator from magnetic locking apparatus at power-on operation.
2. Description of the Prior Art
In a disk storage apparatus, it is necessary to prevent an actuator (a voice coil motor (VCM), etc.) for moving a transducer head on a recording medium from moving due to external force and from damaging data on a recording surface and the actuator itself, by locking the actuator when the disk storage apparatus is not powered. In a small disk storage apparatus, the magnetic attraction of a permanent magnet is used to lock the actuator.
In this prior art configuration, owing to the magnetic attraction of -the permanent magnet, power is not consumed except when locking is released during a power-on operation. Further, in this configuration, the dimensions of the disk storage apparatus can be reduced because there is mechanically no movable part. Since the power of the actuator is used to unlock, a dedicated electric circuit for unlocking is not needed. Still further, in the configuration, component parts are merely the permanent magnet and its attaching members. Therefore, the configuration is generally adopted because of the advantage that the number of parts is small and a cost can be reduced. The present invention relates to an unlocking apparatus and method of a disk storage apparatus which unlocks an actuator from the permanent magnet.
In prior art, in order to release the actuator from the permanent magnet, positional information (servo information) written between a zone where the actuator is locked (parking zone) and a zone where data is recorded (data zone) on a disk recording medium is used and a seek operation is used for releasing. That is, during a releasing operation, a position of the actuator is detected by reading the positional information and the current which is supplied to the actuator is controlled. The actuator is surely released from the permanent magnet and moved to the data zone. The situation in which the releasing cannot be completed because of insufficient movement or in which the actuator collides with a crash stop due to the excess movement of the actuator is avoided by reading positional information on the disk.
However, the servo information written between the parking zone and the data zone on the disk medium may disappear due to the friction between the transducer head and the disk medium if the actuator is locked and released many times, because the parking zone is a zone on which the transducer head attached to the actuator slides when the rotational rate of the disk is below a predetermined value (contact start and stop). Once the servo information is lost, releasing cannot be completed because the positional information for the releasing cannot be obtained any more. In the prior art, there is therefore a problem in terms of reliability.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve a problem of a conventional unlocking apparatus of a disk storage apparatus, in which positional information is lost by the contacting start and stop of a transducer head and therefore it becomes impossible any more to release the locking of the actuator locked by a magnet.
According to the present invention, a disk storage apparatus is previously given acceleration current and acceleration time which should be supplied to an actuator so as to release the actuator from the permanent magnet against the attraction of the magnetic force, and deceleration current and deceleration time which should be supplied to the actuator so as to stop the actuator at a data zone on the disk. When the actuator is unlocked, the actuator is driven according to the previously stored acceleration current, acceleration time, deceleration current, and deceleration time. Therefore, according to the present invention, it is unnecessary to write positional information of the actuator between a parking zone and the data zone on a disk to release the actuator. In consequence, an unlocking apparatus or method according to the present invention can gain in reliability. The present invention is hereinafter described in accordance with a preferred embodiment in conjunction with drawings.
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Patent Abstracts of Japan, vol. 7, No. 70 (P-185), Mar. 23, 1982, JP-A-57 212 668 (Richoh), “Floppy Disk Driving Device”.
Patent Abstract of Japan, vol. 7, No. 75 (P-187), Mar. 29, 1983, JP-A-58 006 560 (Fujitsu), “Magnetic Disk Device”.
Fukushima Yukio
Kimura Jun-ichi
Billion Richard E.
Gamon Owen J.
International Business Machines - Corporation
Letscher George J.
Truelson Roy W.
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