Dynamic magnetic information storage or retrieval – Head – Head accessory
Reexamination Certificate
2002-03-26
2004-06-08
Cao, Allen (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head accessory
C360S254400
Reexamination Certificate
active
06747843
ABSTRACT:
TECHNICAL FIELD
This invention relates to ramps used to park read-write head sliders in disk drives.
BACKGROUND ART
Disk drives are an important data storage technology based on several crucial components including disk media surfaces and read-write heads. When in operation, the rotation of disk media surfaces, with respect to the read-write heads, causes each read-write head to float a small distance off the disk media surface it accesses.
When the disk media surface is not rotating with respect to the read-write head, mechanical vibrations acting upon the disk drive can cause the read-write head to collide with the disk media surface, unless they are separated.
This separation is often referred to as “parking” the read-write heads. Parking the read-write heads minimizes the possibility of damaging the disk media surfaces and/or the read-write heads due to these mechanical collisions. Often such parking mechanisms include a ramp, on which the head slider(s) are “parked”, and a latch mechanism.
When the disk media surfaces are rotating, the read-write head(s) are very close to the disk media and they often pickup traces of the lubricants used in the disk drive. These traces of lubricant degrade the ability of a read-write head to access the disk media surface.
FIG. 1A
illustrates a typical prior art high capacity disk drive
10
including actuator arm
30
with voice coil
32
, actuator axis
40
, suspension or head arms
50
-
58
with slider/head unit
60
placed among the disks.
FIG. 1B
illustrates a typical prior art high capacity disk drive
10
with magnet actuator
20
, actuator arm
30
with voice coil
32
, actuator axis
40
, head arms
50
-
54
and Head Suspension Assemblies (HSA's)
60
-
66
with the disks removed.
Since the 1980′s, high capacity disk drives
10
have used voice coil actuators
20
-
66
to position their read/write heads over specific tracks. The heads are mounted on head sliders at the far end of HSA's
60
-
66
from the voice coil
32
. The heads float a small distance off the disk drive surface
12
when in operation. Often there is one head slider for a given disk drive surface. There are usually multiple heads in a single disk drive, but for economic reasons, usually only one voice coil actuator.
Voice coil actuators are further composed of a fixed magnet actuator
20
interacting with a time varying electromagnetic field induced by voice coil
32
to provide a lever action via actuator axis
40
. The lever action acts to move head arms
50
-
54
positioning head slider units
60
-
66
over specific tracks with remarkable speed and accuracy. Actuator arms
30
are often considered to include voice coil
32
, actuator axis
40
, head arms
50
-
54
and HSA's
60
-
66
. Note that actuator arms
30
may have as few as a single head arm
50
. Note also that a single head arm
52
may connect with two HSAs
62
and
64
.
FIG. 2A
illustrates a Contact Start Stop (CSS) actuator arm
30
of the prior art.
A magnet is affixed to the tail end of the voice coil
32
region, which when near a second magnet located in either the top yoke or bottom yolk of the fixed magnet region
20
, will tend to attract actuator
30
to a parking site often inside the disk media. Magnetic latches are used with CSS designs.
The outside disk surface approach to parking read-write heads parks the read-write head or heads on a ramp outside the disk surface, removing and/or minimizing the possibility for contact when the disk is not in operation.
Read-write heads must be positioned very accurately over the track in the disk media surface they are to access. Errors in this activity are known as track positioning errors, triggering a Position Error Signal (PES).
For a CSS drive, the lubricant pickup by the read-write head(s) during the track seeking process results in a phenomena known as “flying stiction”. Flying stiction may lead to experiencing a high stiction force at the mechanical interface of the read-write head and the disk media surface. The high stiction force at the mechanical interface between the read-write head and the disk media surface may lead to track positioning errors.
FIG. 2B
illustrates an actuator arm
30
including head suspension assembly
60
with head slider
90
on ramp
100
for a parking mechanism outside the disk media surface
12
(not shown), as found in the prior art.
FIG. 3
illustrates a prior art loading ramp
100
engaging lifting tab
92
coupled with head slider
90
by a head suspension assembly
60
positioning the read-write head of head slider
90
in a parking zone with lifting tab
92
engaging loading ramp
100
in region
104
.
To park the read-write head, the head suspension assembly
60
moves from the left, with lifting tab
92
engaging the loading ramp at engagement region
102
and proceeding to region
104
. This places the read-write head
90
into its parking zone.
Block
106
acts to limit lifting tab
92
and, therefore, the read-write head of slider
90
, from moving upward, while region
104
acts to limit lifting tab
92
and the read-write head of slider
90
from moving downward. The rising sections on either side of region
104
further act to limit accidental movement of lifting tab
92
and the coupled head slider
90
in the horizontal directions.
Region
108
of loading ramp
100
is often used during the assembly of a disk drive in a fashion similar to engagement region
102
. Movement of lifting tab
92
is from the right engaging loading ramp
100
at
108
and proceeding to region
104
to park the read-write head.
For a ramp loading disk drive, the read-write head(s) do not rest on the media
12
during the start and stop operations of the disk drive. A central advantage to such disk drives is improved mechanical shock resistance. Improved shock resistance increases the durability and life expectancy of the disk drive.
However, ramp-loading disk drives also present some new problems. Any lubricant that is picked up by the read-write head is more likely to stay on the read-write head, rather than get smeared on the disk media.
Lubricants migrate due to disk rotation onto the disk media surface. After a time, some of the migrated lubricant enters the mechanical interface between the read-write head and the disk media surface, making contact, and sticking to the read-write head. When this occurs, the read-write head tends to stick to the disk media surface, which is known as lubricant stiction. Lubricant stiction is a known cause of track positioning errors. In extreme cases, lubricant stiction acts as a glue between the read-write head and the disk media surface, preventing the disk media surface from rotating at the proper speed. Sometimes the disk media surface cannot rotate at all.
Lubricant stiction is likely to become more pronounced as the flying height of the read-write heads over the disk media surface decreases. Therefore, track positioning errors from lubricant stiction are likely to increase as the flying height decreases.
To summarize, what is needed is a method and/or apparatus removing at least some of the lubricant picked up by a read-write head for a ramp loading disk drive.
SUMMARY OF THE INVENTION
The invention solves at least all the problems discussed for ramp loading disk drives.
The invention includes a method of wiping a read-write head on a ramp including the following. Loading the read-write head into a parking region based upon the lifting tab engaging the loading ramp. Wiping the read-write head on a wiping part of the loading ramp when the lifting tab engages the loading ramp and when the read-write head is outside in the parking region. Note that the wiping part is a convex finger crossing the read-write head path of motion with respect to the lifting tab engagably moving across the loading ramp.
The invention includes a loading ramp for a read-write head coupled to a lifting tab by a head suspension assembly. The loading ramp includes the following. A lifting tab path for engaging the lifting tab to create a motion path for the read-write head based upo
Chang Joseph
Lee Hyung Jai
Sharma Vinod
Aiello Jeffrey P.
Gregory Smith & Associates
Jennings Earle
Samsung Electronics Co. LTD
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