Dynamic magnetic information storage or retrieval – Head mounting – For moving head into/out of transducing position
Reexamination Certificate
2000-12-01
2002-10-29
Korzuch, William (Department: 2653)
Dynamic magnetic information storage or retrieval
Head mounting
For moving head into/out of transducing position
Reexamination Certificate
active
06473269
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to data storage disk drives and in particular to latching a read/write arm that moves a read/write head over the surface of a magnetic data storage disk.
BACKGROUND OF THE INVENTION
Magnetic disk drives for data storage are an integral part of almost all computers. A conventional magnetic disk drive comprises at least one magnetic data disk on which data bits can be recorded by changing the state of magnetic domains on the surface of the disk. The disk drive also comprises a read/write head, hereinafter referred to as a “data head” for each of the at least one disk for “writing” or “reading” the domains on the disk surface. The data head for a disk is located at one end of a read/write arm, hereinafter referred to as a “drive arm”. A drive arm motor moves the drive arm so as to accurately position the data head over different regions of the surface of the disk used for data storage in order to read or write data to these regions. The disk drive comprises a drive frame to which the at least one data disk, drive arm and other parts of the disk drive are mounted.
When in use, the disk is rotated at high speed by a spindle motor. The rotation causes a cushion of air to form between the data head and the disk surface that keeps the data head a small (generally less than a micron), substantially constant, distance from the disk surface. The air cushion thereby prevents direct and possibly damaging contact between the data head and the surface of the disk while the data head moves over the surface of the disk. In effect, the data head glides “frictionless” over the surface of the disk on an air bearing.
When not in use the disk is stationary and the drive arm is rotated into a parking position so that the data head is positioned away from regions of the surface of the disk that are used for data storage. The drive arm is secured in the parking position by a latching device. The latching device prevents an external shock or blow delivered to the disk drive from dislodging the drive arm from the parking position and causing the data head to come into contact with the disk surface while the disk is stationary.
Among prior art latching devices, hereafter referred to as “latches”, used to secure a drive arm in a parking position are solenoid latches, magnetic capture latches, inertial latches and vane latches.
Solenoid latches use a solenoid or coil to produce a magnetic field that moves a locking pin or locking arm so as to engage and immobilize a drive arm in a parking position. Solenoid latches are often complicated, large and heavy, and their solenoids or coils must generally be shielded or distanced from the drive arm to prevent the magnetic fields of the solenoids or coils from affecting the operation of the drive arm motor.
Magnetic capture latches use a small permanent magnet and a strike plate formed from a ferromagnetic material to secure a drive arm in a parking position. Either one of the magnet or strike plate, is mounted on the drive arm and the other is mounted to the drive frame. When the drive arm enters the parking position the permanent magnet and strike plate come into contact and held together by the force of magnetic attraction between them. The drive arm is released from the parking position when the motor that moves the drive arm exerts sufficient force to pull the magnet and strike plate apart. Magnetic capture latches are often unreliable and release when the disk drive is subjected to a shock or blow that results in a force to the latch greater than the magnetic force binding the magnet and latch plate. Furthermore, the magnet must often be shielded to prevent its magnetic field from interfering with the motion of the drive arm. Also, the drive arm motor must be able to pull the magnet and strike plate apart in order to release the drive arm from the parking position. As a result, disk drives using magnetic capture latches often require drive arm motors that are stronger and heavier than drive arm motors used in disk drives operated with other types of latching devices.
An inertial latch uses the inertia of a drive arm and a locking element of the inertial latch to prevent the drive arm from dislodging from a parking position. When a shock or blow is delivered to a disk drive fitted with an inertial latch, the inertia of the locking element and drive arm cause the locking element and drive arm to move relative to each other in such a way that the locking element engages the drive arm and prevents the drive arm from leaving the parking position. Many inertial latches are unreliable and suffer from the fact that for certain directions of a shock or blow delivered to the disk drive, the inertial latch does not move so as to engage the drive arm.
With a vane latch, a drive arm is secured in a parking position by an air vane. The air vane is a thin generally rectangular sheet of material having two large planar surfaces. It is mounted in a disk drive close to and over a data disk of the disk drive with the large planar surfaces parallel to the plane of the data disk. When the drive arm is in the parking position a hole in the air vane engages a protuberance on the drive arm, thereby locking the drive arm in the parking position. When the disk rotates, air between the air vane and the disk is accelerated causing a Bernoulli effect to draw the air vane towards the disk and displace the hole in the air vane from the protuberance on the drive arm. The drive arm is thereby released from the parking position. Air vanes used in air vane latches are often large and air vane latches used in disk drives having multiple disks generally require more space between the disks than would be required using other types of latches. As a result, a disk drive using a vane latch must often be made larger and heavier than disk drives using other types of latches.
It would be desirable to have an improved latch for a disk drive, that is light weight and small that reliably secures a drive arm in a parking position and prevents it from being dislodged from the parking position when the disk drive is subjected to a shock or blow.
SUMMARY OF THE INVENTION
It is an object of one aspect of some preferred embodiments of the present invention to provide an improved latch for locking a drive arm of a disk drive in a parking position that is small and light weight.
It is an object of another aspect of some preferred embodiments of the present invention to provide a latch that has a locking action that is substantially unaffected by a blow or shock delivered to a disk drive in which the latch is installed.
According to another aspect of some preferred embodiments of the present invention, the latch has a locking action that is substantially unaffected by the direction of a blow or shock delivered to the disk drive.
According to another aspect of some preferred embodiments of the present invention the latch does not require a drive arm motor of the drive arm to provide force in order to release the locking action of the latch.
An object of yet another aspect of some preferred embodiments of the present invention is to provide a latch that does not produce a magnetic field that interferes with the operation of a disk drive in which the latch is installed.
Another aspect of some preferred embodiments of the present invention provides a latch, for locking a drive arm in a parking position, that has low power consumption and consumes power only when the drive arm is released from the locking position.
It is an object of yet another aspect of some preferred embodiments of the present invention to provide a latch operated by a piezoelectric micromotor.
A latch for locking a drive arm of a disk drive in a parking position, in accordance with a preferred embodiment of the present invention, comprises a latch stop and a latch hook.
The latch stop comprises a baffle that is moveable between an open and closed position. The latch hook is preferably mounted to the drive arm near or at the end of the drive arm distant from the data head. The latch hook moves with the d
Avital Alon
Ganor Ze′ev
Rafaeli Izhak
Beacham Christopher R.
Fenster & Company Patent Attorneys Ltd.
Korzuch William
Nanomotion Ltd.
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