Abstract:
The invention includes a method of wiping a read-write head on a ramp and the loading ramp apparatus, as well as a disk drive using the method and/or containing the loading ramps.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to ramps used to park read-write head sliders in disk drives.  
         BACKGROUND ART  
         [0002]    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.  
           [0003]    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.  
           [0004]    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.  
           [0005]    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.  
           [0006]    [0006]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.  
           [0007]    [0007]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&#39;s)  60 - 66  with the disks removed.  
           [0008]    Since the 1980&#39;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&#39;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.  
           [0009]    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&#39;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 .  
           [0010]    [0010]FIG. 2A illustrates a Contact Start Stop (CSS) actuator arm  30  of the prior art.  
           [0011]    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.  
           [0012]    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.  
           [0013]    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).  
           [0014]    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.  
           [0015]    [0015]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.  
           [0016]    [0016]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 .  
           [0017]    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.  
           [0018]    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.  
           [0019]    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.  
           [0020]    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.  
           [0021]    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.  
           [0022]    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.  
           [0023]    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.  
           [0024]    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  
         [0025]    The invention solves at least all the problems discussed for ramp loading disk drives.  
           [0026]    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.  
           [0027]    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 upon the lifting tab engagably moving along the lifting tab path. A convex finger contacting the motion path of the read-write head provides a wiping of the read-write head. Note that the motion path for the read-write head includes a parking region and the convex finger contacts the motion path outside the parking region.  
           [0028]    When the read-write head is at least partially covered with a lubricant drop providing a lubricant drop surface, the convex finger contacting the motion path of the read-write head comes within a distance of the read-write head motion path. The convex finger, by approaching close to the read-write head motion path, breaks the lubricant drop surface, providing the wiping of the read-write head.  
           [0029]    The invention also includes disk drives containing the loading ramp and the head suspension assembly.  
           [0030]    Note that the loading ramp  2002  may be located outside the disk media surface or inside the disk media surface. When a disk drive contains more than one disk media surface, the loading ramp is preferably located outside the disk media surface. However, when the disk drive contains one disk media surface, it may be preferable to locate the loading ramp inside the disk media surface.  
           [0031]    Locating the loading ramp inside the disk media surface refers to positioning the loading ramp over the disk media surface. This alternative to CSS disk drive parking has the advantage of greater mechanical shock resistance without the problem of lubricant buildup.  
           [0032]    Note that the convex fingers are approximately convex. The convex fingers may approximate an elliptical cylinder, ellipsoid, paraboloid, cylinder, or hemisphere in different embodiments of the invention.  
           [0033]    These and other advantages of the present invention will become apparent upon reading the following detailed descriptions and studying the various figures of the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]    [0034]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;  
         [0035]    [0035]FIG. 1B illustrates a typical prior art high capacity disk drive  10  with actuator  20 , actuator arm  30  with voice coil  32 , actuator axis  40 , head arms  50 - 56  and Head Suspension Assemblies (HSA&#39;s)  60 - 66  with the disks removed;  
         [0036]    [0036]FIG. 2A illustrates a Contact Start Stop (CSS) actuator arm  30  of the prior art;  
         [0037]    [0037]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;  
         [0038]    [0038]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 under block  104 ;  
         [0039]    [0039]FIG. 4 illustrates a loading ramp  2002  including convex fingers  200  and  202  position outside and to the left of the parking zone of the read-write head of slider  90 , in accordance with the invention; and  
         [0040]    [0040]FIG. 5 illustrates a loading ramp  2002  including convex fingers  200  and  202  position outside and to the right of the parking zone of the read-write head of slider  90 , in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]    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 upon the lifting tab engagably moving along the lifting tab path. A convex finger contacts the motion path of the read-write head to provide a wiping of the read-write head. Note that the motion path for the read-write head includes a parking region and the convex finger contacts the motion path outside the parking region.  
         [0042]    When the read-write head is at least partially covered with a lubricant drop providing a lubricant drop surface, the convex finger contacting the motion path of the read-write head comes within a distance of the read-write head motion path. The convex finger, by approaching close to the read-write head motion path, breaks the lubricant drop surface, providing the wiping of the read-write head.  
         [0043]    [0043]FIG. 4 illustrates a loading ramp  2002  including convex fingers  200  and  202  positioned outside and to the left of the parking zone of the read-write head of slider  90 , in accordance with the invention.  
         [0044]    [0044]FIG. 5 illustrates a loading ramp  2002  including convex fingers  200  and  202  positioned outside and to the right of the parking zone of the read-write head of slider  90 , in accordance with the invention.  
         [0045]    Note that in both FIGS. 4 and 5, the lifting tab path from  102  to  104 , engaging lifting tab  92 , creates a motion path for the read-write head in slider  90  based upon engaged lifting tab  92  moving along lifting tab path.  
         [0046]    Note that in both FIGS. 4 and 5, convex finger  200  contacts the read-write head motion path, wiping the read-write head.  
         [0047]    In FIG. 4, convex fingers  200  and  202  contact the read-write head every time the read-write head is parked.  
         [0048]    In FIG. 5, parking the read-write head does not bring the read-write head into contact with convex fingers  200  and  202 . FIG. 5 illustrates a loading ramp  2002  wherein the actuator occasionally directs lifting tab  92  further than required for parking to bring convex finger into contact with the motion path of the read-write head of the head slider  90  coupled to lifting tab  92 .  
         [0049]    In FIGS. 3, 4 and  5 , loading ramp  2002  engages 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 .  
         [0050]    In FIGS. 3, 4 and  5 , 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 of slider  90  into its parking zone.  
         [0051]    In FIGS. 3, 4 and  5 , 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.  
         [0052]    In FIGS. 3, 4 and  5 , 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.  
         [0053]    The invention includes a method of wiping a read-write head on a loading ramp  2002  including the following. Loading the read-write head into a parking region based upon the lifting tab  90  engaging the loading ramp  2002  from  102  through  104 . And wiping the read-write head on a wiping part  200  of the loading ramp  2002  when the lifting tab  92  engages the loading ramp and when the read-write head is outside in the parking region.  
         [0054]    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. Also note that different head suspension assemblies  60  will tend to differ in the motion paths of the read-write heads on the slider  90  coupled to lifting tab  92 .  
         [0055]    Therefore, the inventive loading ramp  2002  will be preferably designed with specifically parameterized head suspension assemblies  60  constraining the motion path of the read-write head with respect to the motion of lifting tab  92  engaging the loading ramp.  
         [0056]    [0056]FIGS. 4 and 5 show loading ramps  2002  which can accommodate up to four head suspension assemblies  60 - 66 , even though only one head suspension assembly  60  has been illustrated. These Figures portray a preferred embodiment economically wiping the read-write heads of an actuator including up to four head suspension assemblies as illustrated in FIGS. 1A and 1B.  
         [0057]    Note that other preferred loading ramps may service as few as one head suspension assembly. Note that other preferred loading ramps may service more than four head suspension assemblies.  
         [0058]    The preceding embodiments have been provided by way of example and are not meant to constrain the scope of the following claims.