Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
1999-11-18
2001-10-09
Ometz, David L. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
C360S254800
Reexamination Certificate
active
06301073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates in general to computer hard disk drives and in particular to an apparatus and method for reducing and/or preventing mechanical shock-induced damage between an actuator arm and a disk file in a computer hard disk drive.
2. Description of the Related Art
Generally, a digital data storage system consists of one or more storage devices that store data on storage media such as magnetic or optical data storage disks. In magnetic disk storage systems, a storage device is called a hard disk drive (HDD), which includes one or more disks and an HDD controller to manage local operations concerning the disks. Hard disks are platters, typically made of aluminum alloy, plastic substrates, or a mixture of glass and ceramic, covered with a magnetic coating. Typically, two or three platters are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
The only other moving part within a typical HDD is the head assembly. Within most drives, one read/write head is associated with each side of each platter and flies just above or in contact with the platter's surface. Each read/write head is connected to a semi-rigid arm apparatus which supports the entire head flying unit. More than one of such arms may be utilized together to form a single armature unit.
Each read/write head scans the hard disk platter surface during a “read” or “write” operation. The head/arm assembly is moved utilizing an actuator which is often a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which is mounted a spindle supporting the disks. The base casting is in turn mounted to a frame via a compliant suspension. When current is fed to the motor, the VCM develops force or torque which is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head nears the desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop directly over the desired track.
If a hard disk drive sustains severe vibration or mechanical shock during operation, the arms of the actuator can contact the disks and may damage them. Although some hard disk drives have restraint mechanisms for withstanding high G-force impacts, they are typically limited to a single non-operational application. For example, a common prior art solution employs a stationary ramp located adjacent to the radial outer edge of the disk pack. When the heads on the arms of the actuator are rotated beyond the outer edges of the disks, the heads or arms are parked on the ramp and are unable to contact the disks. Unfortunately, this design is capable of protecting the drive only when the heads are radially outside of the disks.
In U.S. Pat. No. 5,668,682, a detachable disk drive having a head lift mechanism is disclosed. The mechanism moves the actuator arm and, thus, the head away from the disk when the drive is removed from a slot in a laptop computer. When the drive is inserted into the slot in the laptop computer, the actuator arm is automatically released so that the head may contact the disk for normal read/write operations. Unfortunately, the mechanism is limited to preventing contact between the actuator arm and the disk when the drive is removed from the laptop computer. Thus, if the laptop undergoes shock when the drive is installed, the actuator arm will not be prevented from striking the disk, regardless of the operational status of the drive of the radial position of the actuator arm. Therefore, an improved disk drive for preventing shock-induced contact between the actuator arm and disk is needed.
SUMMARY OF THE INVENTION
A hard disk drive for a computer has a base containing a stack of rotatable disks and an actuator with a set of arms that is pivotable relative to the disks. At least one magnetic head is mounted to each arm for reading information from or writing information to a respective disk. The drive also has a stationary shock support member or comb located adjacent to the outer edges of the disks and the actuator. The teeth of the comb are interposed with the disks and arms throughout the range of pivotal motion of the arms. The teeth prevent incidental contact between the disks and arms in the event of mechanical shock to the hard disk drive.
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M. Hashimoto, H. Kajitani and N. Tagawa; Development of a New Sub-Sub Micron Flying Ramp-Loading Head with Emphasis on Slider Roll Control Capability; IEE Transactions on Magnetics, vol. 28, No. 5, Sep., 1992, pp. 2536-2538; Manuscript received Feb. 17, 1992.
Gillis Donald
Suk Mike
Altman, III Franklin D.
Bracewell & Patterson L.L.P.
International Business Machines - Corporation
Martin Robert B.
Ometz David L.
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