Patent Abstract:
Windage proximate to a spinning disk within a disk drive is directed through a plurality of apertures in a ramp situated near the outside diameter of the disk. A tab extending from a load beam that supports a slider rests on the ramp when the drive is not in use. When the drive is started the disk begins to spin and an actuator moves the load beam to bring the slider over the surface of the disk. As the load beam moves, the tab is guided along the ramp and cushioned by the air flow emerging from apertures in the ramp beneath it. When the drive is stopped the actuator brings the load beam back so that the tab engages the ramp. A cushion of air is again provided as the tab is moved along the ramp as the tab is returned to a parked position.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to magnetic disk data storage systems, and more particularly to the use of a ramp to facilitate the loading and unloading of sliders.  
           [0002]    Magnetic disk drives are used to store and retrieve data for digital electronic apparatuses such as computers. In FIGS. 1A and 1B, a magnetic disk data storage system  10  of the prior art includes a sealed enclosure or housing  12 , a spindle motor  14 , a magnetic medium or disk  16 , supported for rotation by a drive spindle S 1  of the spindle motor  14 , a voice-coil actuator  18  and a load beam  20  attached to an actuator spindle S 2  of voice-coil actuator  18 . A slider support system consists of a flexure  22  coupled at one end to the load beam  20 , and at its other end to a slider  24 . The slider  24 , also commonly referred to as a head or a read/write head, typically includes an inductive write element with a sensor read element.  
           [0003]    As the motor  14  rotates the magnetic disk  16 , as indicated by the arrow R, an air bearing is formed under the slider  24  allowing it to “fly” above the magnetic disk  16 . Discrete units of magnetic data, known as “bits,” are typically arranged sequentially in multiple concentric rings, or “tracks,” on the surface of the magnetic disk  16 . Data can be written to and/or read from essentially any portion of the magnetic disk  16  as the voice-coil actuator  18  causes the slider  24  to pivot in a short arc, as indicated by the arrows P, over the surface of the spinning magnetic disk  16 . The design and manufacture of magnetic disk data storage systems is well known to those skilled in the art.  
           [0004]    Reducing the distance between the slider  24  and the spinning disk  16 , commonly known as the “fly height,” is desirable in magnetic disk drive systems  10  as bringing the magnetic medium closer to the inductive write element and sensor read element improves signal strength and allows for increased areal densities. However, as the fly height is pushed to lower values, the effects of contamination at the head-disk interface become more pronounced. Specifically, debris may be collected over time on the air bearing surface of the slider  24  and which may ultimately cause the slider  24  to crash into the magnetic disk  16  causing the disk drive system  10  to fail. Consequently, reducing contamination within the sealed enclosure  12  is a continuing priority within the disk drive industry.  
           [0005]    One strategy that has been used to reduce the debris that collects on slider  24  is to focus on the tribology at the head-disk interface to reduce the amount of contact between the slider  24  and the disk  16  when the system  10  is started and stopped. Traditionally, when a system  10  was shut down the slider  24  was parked on a track at the inner diameter (ID) of the disk  16  commonly known as a landing zone. There the slider  24  would rest in contact with the surface of the disk  16  until the disk was spun again, at which point the air bearing would form and the slider  24  would lift back off of the surface. Unfortunately, the friction and wear that occurred in these systems at the head-disk interface, even with improved lubricants, created unacceptable amounts of debris on the slider  24  to allow for still lower fly heights. In order to reduce friction and wear at the head-disk interface so as to reduce debris accumulation, the landing zone was improved by making it textured, often with a pattern of bumps, in order to reduce the contact area between the slider  24  and the disk  16 , among other reasons.  
           [0006]    Textured landing zones proved effective to a point, however the need to fly the slider  24  still lower, with the inevitable need to reduce contamination further, lead to the development of techniques whereby the slider  24  is held off of the surface of the disk  16  when not in use. Such techniques seek to avoid any contact between the slider  24  and disk  16  at all. However, simply lifting the slider  24  higher off of the surface of the disk  16  is not sufficient because a system  10  in a portable computer system is subject to shock that can cause the slider  24  to slap into the disk  16 . Therefore, a technique used in the prior art to securely park the slider  24  away from the surface of the disk  16 , as shown in FIG. 2, is to employ a small ramp  30  placed proximate to the outer diameter (OD) of the disk  16  and a tab  32  attached to the slider  24 . As the voice-coil actuator  18  causes the slider  24  to move toward the extreme OD the tab  32  rides up on the ramp  30  and lifts the slider  24  away from the surface. The slider  24  is pushed still further along the ramp  30  past the OD of the disk  16  to be parked on a flat or slightly indented portion on the ramp  30 .  
           [0007]    [0007]FIGS. 3 and 4 serve to better illustrate the relationships between the components of ramp systems of the prior art. FIG. 3 shows an elevational view, taken along the line  3 - 3  in FIG. 2, of a slider  24  of the prior art suspended beneath a load beam  20  by a flexure  22 . Attached to the end of the load beam  20  is a tab  32  intended to move in sliding contact with a ramp  30  for loading and unloading the slider  24 . Although shown as attached to the end of the load beam  20 , it should be noted that the tab  32  is typically formed as an integral part of the load beam  20 .  
           [0008]    [0008]FIG. 4 shows an elevational view, taken along the line  4 - 4  of FIG. 2, of the ramp  30  relative to the tab  32 , read slider  24 , and the disk  16 , when the slider  24  is flying and the tab  32  is disengaged from the ramp  30 . For clarity, the load beam  20  and the flexure  22  are not shown. The tab  32  has a rounded bottom surface to reduce the contact area with the ramp  30  when the two are in sliding contact. Arrows in FIG. 4 indicate the directions of motion of the load beam  20  for both loading and unloading.  
           [0009]    One problem with a ramp  30  of this design is that the tab  32  is in sliding contact with the ramp  30  each time the system  10  is started or stopped. The sliding contact produces wear contamination that can be transferred to the disk  16  to be picked up by the air bearing surface of the slider  24 . The wear may be reduced by shaping the tab  32  so that the surface that contacts the ramp  30  is convex and by employing a lubricant. Although the amount of wear debris formed in this way is less significant compared to that which is generated with textured landing zones, nevertheless it may interfere with the aerodynamics of the slider  24  at very low fly heights and lead to crashes.  
           [0010]    Another problem encountered with ramps  30  is that the slider  24  is not entirely parallel to the surface of the disk  16 . Rather, the leading edge of the slider  24 , the one facing into the direction of the rotation of the disk  16 , is higher than the trailing edge of the slider  24  to provide lift. Viewed another way, the pitch on the slider  24  causes the trailing edge to be closer to the surface. Similarly, since the air flow under the side of the slider  24  nearest the OD is always greater than under the side nearest the ID, the slider  24  may have some roll such that the ID edge of the slider is lower than the OD edge. Consequently, the corner of the slider  24  on the ID side of the trailing edge is commonly closest to the surface. As a slider  24  is loaded over a disk  16  the tab  32  slides down the ramp  30  until the lift experienced by the slider  24  is sufficient to cause the slider to fly.  
           [0011]    What is desired, therefore, is a way to park the slider  24  on a ramp  30  while minimizing as much as possible the wear between the tab  32  and the ramp  30 . It is further desired to provide a smoother transition during loading and unloading.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention provides for a ramp to assist the loading and unloading of a slider in a magnetic disk drive. The ramp comprises a body having a first surface and a second surface and a plurality of apertures extending between them, where each aperture has a first opening at the first surface and a second opening at the second surface. The first surface of the ramp further comprises a sloped segment and a straight segment, with the sloped segment being acutely angled with respect to the second surface. The ramp of the present invention directs a portion of a flow of air proximate to a spinning disk through the apertures in order to lift and cushion a tab attached to a load beam from which a slider is also suspended.  
           [0013]    In a preferred embodiment of the present invention the air flow emerging through the first openings is sufficient to suspend the tab above the surface of the ramp. By maintaining an air bearing between the tab and the ramp while the slider is loaded and unloaded, wear and contamination from sliding contact can be greatly reduced. Another advantage realized by the present invention is that an air bearing can smooth the transition both as the tab leaves the ramp during loading of the slider, and as the tab re-engages the ramp during unloading.  
           [0014]    In other embodiments the air flow emerging through the first openings is not sufficient to hold the tab completely off of the surface of the ramp. In still other embodiments the air flow emerging through the first openings is sufficient to hold the tab completely off of the surface of the ramp only over some length of the ramp such as the sloped segment. These embodiments still provide an advantage over the prior art in that any lift at all that is provided to the tab will tend to reduce the contact force between the ramp and the tab. Any reduction in the contact force will further tend to reduce wear and contamination from sliding contact. The lift provided to the tab in these embodiments, although not enough to suspend it completely off of the surface of the ramp, nevertheless can also smooth the transitions as the tab engages and disengages from the ramp.  
           [0015]    Further embodiments of the ramp are directed at variations of the second surface. The second surface may be flat, but in some embodiments the second surface is non-planar and shaped to better urge a flow of air proximate to the surface of the disk into the plurality of apertures. For example, the second surface may be concave or may be provided with an aerodynamic shape. Shaping the second surface is advantageous to the present invention in that it provides a greater air flow into the plurality of apertures thus providing a greater lifting force against a tab situated above the first surface.  
           [0016]    Still other embodiments are directed towards the apertures themselves. Each aperture has a first and second opening and in some embodiments their cross-sectional areas are substantially equal. In other embodiments the cross-sectional area of the first opening is less than the cross-sectional area of the second opening. In further embodiments the apertures are substantially straight, while in others they take complex paths through the body of the ramp. For example, an aperture may have an S-shape. Yet other embodiments are directed towards apertures that intersect the second surface at an angle to a tangent of the second surface at the location of the aperture&#39;s second opening. Still more embodiments are directed to apertures that branch within the body of the ramp such that a second opening may connect to more than one first opening. Yet other embodiments are directed to apertures having nozzles formed at their first openings. Finally, some embodiments are directed to the cross-sectional shapes of the first and second openings and to the arrangements of the openings on the first and second surfaces.  
           [0017]    The embodiments directed at different aperture configurations are advantageous in that they allow an air flow to be collected in a first location, say over the OD of the disk, to be redirected to a second location that is not directly over the first location, such as the straight segment of the ramp. These embodiments also allow the air flow out of the apertures to be shaped and otherwise manipulated, for example by providing nozzles to increase the speed of the air flow. Such variations provide greater lift to a tab over some regions of the ramp than over other regions. A properly shaped aperture can reduce turbulence and thus reduce resistance to the flow of air.  
           [0018]    More embodiments are directed at ramp systems for loading and unloading at least two sliders. Such an embodiment comprises a body having a first portion and a second portion where each portion is a ramp as described above, and the first portion is proximate to a first surface of a disk and the second portion is proximate to a second surface of the disk. The two portions, taken together, provide the body of the ramp system. The ramp system can be positioned around the OD of the disk. This design is desirable as disk drives typically are configured to be able to utilize both surfaces of a magnetic disk by employing a separate slider for each.  
           [0019]    Further embodiments are directed to disk drives for storing and retrieving magnetic data comprising a housing containing a rotatable magnetic disk, an actuator configured to pivot a load beam proximate to a surface of the disk, a slider and a tab each attached to the load beam, the tab extending the load beam in a first direction, and a ramp as described above. The ramp is situated such that the tab engages a sloped segment of the ramp as the load beam is pivoted to an outside diameter of the surface of the disk. Additional embodiments of the disk drive are directed to variations of the tab, and specifically to the surface of the tab that faces the ramp. This surface may have a non-planar component, for example, it can be concave or have an aerodynamic shape to help it glide on the air bearing. Shaping the surface of the tab can be an advantage in that it allows the tab to experience a greater lifting force from the air flow provided by the apertures beneath it.  
           [0020]    Lastly, embodiments are directed to methods for loading and unloading a slider. Both methods include providing a rotatable magnetic disk disposed within a housing, providing an actuator disposed within the housing and configured to pivot a load beam proximate to a surface of the disk, providing a slider and a tab attached to the load beam wherein the tab extends the load beam in a first direction, and providing a ramp as described above. The method of loading the slider further includes rotating the magnetic disk to provide an air flow through the plurality of apertures, pivoting the load beam while the air flow through the apertures provides a lifting force to the tab as it moves with respect to the ramp from a straight segment to a sloped segment, and finally flying the slider such that the tab disengages from the ramp.  
           [0021]    The method of unloading the slider further includes flying the slider over the disk, pivoting the load beam such that the tab engages a sloped segment of the ramp as the load beam is pivoted to an outside diameter of the disk, moving the tab over the sloped segment and onto the straight segment of the ramp, and reducing the rotation of the disk to reduce the flow of air through the apertures to allow the tab to be supported on the straight segment of the ramp. Further embodiments of both methods include supporting the tab on an air bearing while it is moving relative to the ramp. Other embodiments of both methods are directed to providing an amount of lift to the tab that is not sufficient to raise the tab off of the ramp, but is sufficient to lower the contact force between the tab and the ramp.  
           [0022]    These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions of the invention and a study of the several figures of the drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements.  
         [0024]    [0024]FIG. 1A is a partial cross-sectional elevation view of a magnetic data storage system of the prior art;  
         [0025]    [0025]FIG. 1B is a top plan view of the magnetic data storage system taken along line  1 B- 1 B of FIG. 1A;  
         [0026]    [0026]FIG. 2 is a top plan view of a magnetic data storage system equipped with a ramp and a tab of the prior art;  
         [0027]    [0027]FIG. 3 is an elevational view taken along the line  3 - 3  of FIG. 2  
         [0028]    [0028]FIG. 4 is an elevational view taken along the line  4 - 4  of FIG. 2;  
         [0029]    [0029]FIG. 5 is a perspective view of a ramp of the present invention;  
         [0030]    [0030]FIG. 6A is a partially broken view of the ramp of FIG. 5;  
         [0031]    [0031]FIG. 6B is an elevational view of a cross-section of a portion of a ramp provided with an aperture;  
         [0032]    [0032]FIG. 7 is a cross-section of an alternative embodiment of a ramp showing a branching of apertures;  
         [0033]    [0033]FIG. 8A is a cross-section of a ramp system of the present invention for one disk;  
         [0034]    [0034]FIG. 8B is a cross-section of a ramp system of the present invention for a disk stack;  
         [0035]    [0035]FIG. 9 is a plan view of the ramp showing various first opening shapes and arrangements;  
         [0036]    [0036]FIG. 10A is a cross-section of an alternative embodiment of the ramp of the present invention;  
         [0037]    [0037]FIGS. 10B and 10C are side elevational views of alternative embodiments of the ramp of the present invention;  
         [0038]    [0038]FIG. 10D shows an elevational view of the ramp situated above the disk to show how the second surface may be shaped along the minor axis of the ramp;  
         [0039]    [0039]FIG. 11 shows a cross-section of the tab of the present invention disposed over the ramp;  
         [0040]    [0040]FIG. 12 shows a flow diagram for the method of loading the slider; and  
         [0041]    [0041]FIG. 13 shows a flow diagram of for the method of unloading the slider.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]    [0042]FIGS. 1A, 1B, and  2 - 4  were discussed above with reference to the prior art.  
         [0043]    [0043]FIG. 5 shows a perspective view of the ramp  40  of the present invention. The ramp  40  comprises a body  42  having a first surface  44  and a second surface  46  and a plurality of apertures  48  extending between the two. The body  42  is preferably formed of a plastic, such as Teflon, or plastic-like material selected for having very low levels of outgassing of volatile organic compounds and very low levels of particle shedding. The body  42  should also be formed of a material that is resistant to wear and that can be readily machined or otherwise formed. In some embodiments ceramic materials or metallic materials can be used to form the body  42 . Further embodiments include surface treatments, lubricants, and specially formed solid surface layers to provide additional wear resistance to first surface  44 .  
         [0044]    The first surface  44  is further divided into two sections, a straight segment  50  and a sloped segment  52 , the sloped segment  52  being acutely angled with respect to the second surface  46 . The straight segment  50  is a location where a tab  32  rests when a slider  24  is parked. Although shown as flat in FIG. 5, the straight segment  50  in other embodiments can be provided with a notch, a step, or a depression, for example, to more securely hold the tab  32  when the slider  24  is at rest. Such designs are well known in the art. The sloped segment  52  provides a transition region to guide the slider  24  towards the surface of the disk  16  during loading, and to gently bring the slider  24  away from the surface of the disk  16  when unloading. While the sloped segment  52  is shown in FIG. 5 as being a flat section acutely angled with respect to the second surface  46 , the sloped segment  52  take more complex forms in other embodiments. For example, the sloped segment  52  can be contoured so that towards one end it smoothly transitions into the straight segment  50  and on the other end it is flared to be more nearly parallel to the plane defined by the surface of the disk  16 .  
         [0045]    The ramp  40  is situated such that it partially overhangs the OD of the disk  16 . As the disk  16  rotates, a layer of air proximate to the surface of the disk  16  is swept along with it. This flow of air is commonly known as windage. The air flow near the OD of the disk  16  is complex and will be affected in the vicinity of the ramp  40  both by the ramp  40  itself and by the presence of the nearby slider  24  and load beam  20 . In general, however, the air flow near the OD has both radial and circumferential components, moving both towards the OD of the disk  16  and in the direction of the rotation of the disk  16 . The second surface  46  can be shaped in order to better capture some of the air flow underneath the ramp  40 . An advantageous shape of the second surface  46  can direct a greater portion of the air flow near the OD of the disk  16  into the plurality of apertures  48  so that more air will emerge through the first surface  44  as shown by the arrows in FIG. 5.  
         [0046]    [0046]FIG. 6A shows a partially broken view of the ramp  40  taken along the line  6 - 6  of FIG. 5 to illustrate various embodiments of apertures  48 . In one embodiment, an aperture  48 ′ has a first opening  54 ′ at the first surface  44  and a second opening  56 ′ at the second surface  46 . For this aperture  48 ′ the cross-sectional areas of the first opening  54 ′ and the second opening  56 ′ are substantially equal and the aperture  48 ′ between them is substantially straight and perpendicular to the second surface  46 . Aperture  48 ′ represents the simplest type of aperture  48  and should be the easiest to manufacture, for example, by laser drilling.  
         [0047]    Aperture  48 ″ shows a more complex aperture  48 . Aperture  48 ″ differs from aperture  48 ′ in four ways: the cross-sectional area of the first opening  54 ″ is less than the cross-sectional area of the second opening  56 ″, the aperture  48 ″ is neither straight nor perpendicular to the second surface  46 , and the first opening  54 ″ includes a nozzle region  55 . Of course, other embodiments may be more complex than aperture  48 ′ while less complex than aperture  48 ″. For example, one embodiment of aperture  48  might be straight with a cross-sectional area of the first opening  54  less than the cross-sectional area of the second opening  56  and not include a nozzle  55 .  
         [0048]    Non-linear apertures  48  can be used to bring an air flow from a second opening  56  situated over the surface of the disk  16  to a first opening  54  on the first surface  44  that is substantially distant from the OD of the disk  16 . In order to provide a flow of air to the straight segment  50 , for example, it may be necessary to direct the flow of air from second openings  56 , located proximate to the OD of the disk  16 , through a plurality of apertures  48  and to first openings  54  located on the straight segment  50 . Aperture  48 ″ in FIG. 6A illustrates this configuration. Aperture  48 ″ also illustrates a nozzle region  55  that is shaped to increase the speed of the air as it exits through the first opening  54 ″.  
         [0049]    [0049]FIG. 6B is an elevational view of a cross-section of a portion of a ramp provided with an aperture  48  that intersects the second surface  46  at an angle α to a tangent T of the second surface  46  at the location of the second opening  56 . In some embodiments it is desirable to angle the apertures  48  at the second surface  46  to take advantage of an air flow that impinges on the second surface  46  at or near the angle α to the tangent T of the second surface  46 .  
         [0050]    Other embodiments of apertures  48  involve branching. For example, the second opening  56  can connect to a plurality of first openings  54 . FIG. 7 illustrates two of many possible ways in which such branching can occur. In one embodiment, several apertures  48  lead away from one second opening  56 . In another embodiment, a single aperture  48  splits into two apertures  48 , one of which splits again into two more apertures  48 . In both illustrated embodiments three first openings  54  connect to one second opening  56 , however in other embodiments two first openings  54  connect to one second opening  56  and in still other embodiments more than three first openings  54  connect to one second opening  56 . Yet other embodiments are directed to a ramp  40  where the plurality of apertures  48  includes a selection from amongst the various types of apertures  48  described above. Computer modeling, such as by computational fluid mechanics and computational structural mechanics, can be employed to determine optimal numbers, arrangements, shapings and sizes of the apertures  48 , as will be appreciated by those skilled in the art.  
         [0051]    [0051]FIG. 8A shows a cross-section of a ramp system  70  of the present invention that allows for the simultaneous loading and unloading of two sliders  24  on one disk  16 . The ramp system  70  includes a body having a first portion  72  and a second portion  74 , each portion  72  and  74  including a first surface  44 , a second surface  46 , and a plurality of apertures  48  extending between them. The first portion  72  is proximate to a first surface  73  of the disk  16  and the second portion  74  is proximate to a second surface  75  of the disk  16 . Each portion  72  and  74  is essentially an independent ramp  40 . Since most disk drive systems  10  employ disks  16  having magnetic layers on both surfaces  73  and  75  they also include two sliders  24  attached to independent load beams  20  operated by a single actuator  18 . A ramp system  70  allows the sliders  24  on both sides of the disk  16  to be loaded and unloaded with all of the advantages of the present invention. In disk drive systems  10  having more than one disk  16 , frequently referred to as a disk stack, the ramp system  70  can be built to provide a ramp  40  for each surface  73  and  75  of each disk  16  as shown in FIG. 8B.  
         [0052]    A further benefit of a ramp system  70  is that second surface  46  can be contiguous with the two portions  72  and  74 . Since much of the windage moves in a radial direction as shown in FIG. 8A, the U-shaped portion of the second surface  46  will tend to block the flow of air and direct it instead into the plurality of apertures  48  in the first and second portions  72  and  74 . It should be noted that although shown as U-shaped, this portion can take other forms as well such as a squared-off shape or a V-shape.  
         [0053]    [0053]FIG. 9 shows a plan view of a ramp  40  to illustrate that first openings  54  may have various shapes. These shapes may reflect the cross-sectional shapes of the apertures  48  extending into the ramp  40 , or they may be formed only at the first surface  44 . Such shapes include, but are not limited to, circles, squares and diamonds, ovals or ellipses having different ratios of major to minor axes, commas, and hexagons. Hexagons, for example, are preferably arranged to form a honeycomb structure. The apertures  48  can be arranged in a lattice, such as illustrated by the hexagonal arrangement of the hexagons in FIG. 9, or they can be arranged in concentric circles as shown on the sloped segment  52 , or arranged such that the density of first openings  54  is greatest along the center line of the first surface  44 . Many other arrangements are also possible. Similarly, second openings  56  on the second surface  46  can also take any of these shapes or arrangements.  
         [0054]    FIGS.  10 A- 10 C show ramp embodiments  40  having second surfaces  46  that are specially shaped to direct air into second openings  56 . In FIGS. 10A and 10B the second surface  46  is essentially concave. In FIG. 10A the second surface is further made wavy, grooved, or corrugated so that second openings  56  can be angled to face into the air flow as shown. FIG. 10B shows a second surface  46  that curves below the level of the edge of the disk  16  to better collect the air flow coming off of the disk  16  and urge it into second openings  56 . FIG. 10C shows a more aerodynamically shaped second surface  46  that extends downward over the disk  16  to narrow the gap between the ramp  40  and the disk  16  to increase the speed of the air flow through this gap.  
         [0055]    [0055]FIG. 10D shows an elevational view of a ramp embodiment  40  as seen from a point located over the center of the disk  16 . This perspective shows that the second surface  46  can be shaped along a minor axis of the ramp  40  as well as along a major axis of the ramp  40  as shown in FIGS.  10 A- 10 C. In FIG. 10D the shaping of the second surface  46  along the minor axis of the ramp  40  is concave. However, in other embodiments the second surface  46  can be flat or convex along the minor axis. In still other embodiments the second surface has grooves or channels set along the minor axis, with such grooves or channels extending substantially in the direction of the major axis of the ramp  40 . Computer modeling, such as by computational fluid mechanics and computational structural mechanics, can be employed to design the shape of the second surface  46  for a given air flow around the disk  16 , as will be appreciated by those skilled in the art. Also shown in FIG. 10D is that the straight segment  50  and the sloped segment  52  can be made convex rather than flat to further reduce the contact area between the tab  32  and the ramp  40  if ever they should touch.  
         [0056]    [0056]FIG. 11 shows a cross-section of a tab  80  positioned over the straight segment  50  of a ramp  40 . Tab  80  varies from tab  32  of the prior art shown in FIG. 4 in that tab  80  has a shape designed to take advantage of the flow of air out of first openings  54  to generate lift. The shape of tab  80  in FIG. 11 is essentially concave on the surface  82  that faces the ramp  40 . Just as with the second surface  46  of the ramp  40 , the surface  82  of the tab  80  can be shaped along one or two axes. Hence, the concavity shown in FIG. 11 may represent either a section through a cylinder, a section through a hemispherical cap, or a section through a surface that is partially cylindrical and partially hemispherical. A cylindrical shape to the surface  82  would produce two lines of contact with the first surface  44  when the tab  80  is touching the ramp  40 . A hemispherical shape to the surface  82  would produce a circular line of contact with the first surface  44  when the tab  80  is touching the ramp  40 . Where the first surface  44  is convex, such as shown in FIG. 10D, either a cylindrical shape or a hemispherical shape to surface  82  would produce simply two points of contact with the first surface  44  when the tab  80  is touching the ramp  40 .  
         [0057]    Tab  80  is preferably formed of a plastic, such as Teflon, selected for having very low levels of outgassing of volatile organic compounds and very low levels of particle shedding. The tab  80  should also be formed of a material that is resistant to wear and that can be readily machined or otherwise formed. In some embodiments ceramic materials or metallic materials can be used to form the tab  80 . Further embodiments include surface treatments or specially formed solid surface layers to provide additional wear resistance to the surface  82 . Tab  80  can be made thin to minimize mass, as the air flow coming out of first openings  54  is intended to lift the tab  80  off of the first surface  44  of the ramp  40 . Minimizing mass to make lifting the tab  80  easier also suggests forming the tab  80  from a low-density material. Additionally, the tab  80  can be made wider in a direction parallel to the long axis of the ramp  40 , compared with tabs  32  of the prior art, in order to be situated over a greater number of first openings  54  at any given moment.  
         [0058]    [0058]FIG. 12 shows a flow chart illustrating the process  100  for loading a slider  24  according to the present invention. The process  100  includes the act or operation  102  of providing a magnetic disk  16  within a housing  12 , the act or operation  104  of providing an actuator  18  and a load beam  20 , where the actuator  18  is configured to pivot the load beam  20  proximate to the surface of the disk  16 , the act or operation  106  of providing a slider  24  attached to the load beam  20 , the act or operation  108  of providing a tab  80  attached to the load beam that extends the load beam in a first direction, and the act or operation  110  of providing a ramp of the present invention. The process  100  further includes the act or operation  112  of rotating the disk  16 , the act or operation  114  of pivoting the load beam  20 , and the act or operation  116  of flying the slider  24 .  
         [0059]    Acts or operations  102 ,  104 , and  106  are all well known in the prior art. Act or operation  108  involves providing a tab  80  attached to the load beam  20 . While a tab  80  of the present invention is preferable, it should be noted that a tab  32  of the prior art can also be used. It should also be pointed out that in preferred embodiments the tab  80  or  32  will be integral to the load beam  20  rather than a separate piece that has been joined to the load beam  20 . The tab  80  is intended to extend the load beam  20  in a first direction, where the first direction is defined as the long axis of the load beam  20 . Extending the load beam  20  in a first direction with a tab  32  that is integral to the load beam  20  is also well known in the prior art and is shown in FIGS. 2 and 3. It should also be noted that although the tab  32  in FIG. 3 is shown as projecting out from the top surface of the load beam  20 , the tab  32  or a tab  80  can also be extended from the end of the load beam  20 , or extended from the flexure  22 . The tab  80  needs to extend sufficiently beyond the end of the load beam  20  so that when the tab  80  engages the ramp  40  neither the flexure  22  nor the slider  24  contacts the ramp  40 .  
         [0060]    In act or operation  110  a ramp  40  of the present invention is provided. The ramp  40  should be positioned such that as the actuator  18  pivots the load beam  20  towards the OD of the disk  16  the tab  80  engages the ramp  40 . The ramp  40  should be rigidly attached to the housing  12 , or to another component within the system  10  that itself is rigidly attached to the housing  12 , so that the ramp  40  can be securely positioned proximate to a surface of the disk  16  at the OD. The ramp  40  should be proximate to the surface of the disk  16 , but not so close that a sudden jolt or shock could cause the ramp  40  to contact the disk  16 . In act or operation  110  the ramp should be further positioned so that the tab  80  is in contact with the straight segment  50  of the first surface  44 .  
         [0061]    Act or operation  112  involves rotating the disk  16  in order to provide a flow of air through the plurality of apertures  48 . Since the amount of air flowing through the plurality of apertures  48  is proportional to the speed of the disk  16 , and the lifting force felt by the tab  80  is proportional to the amount of air flowing through the apertures  48 , it is therefore desirable to spin the disk  16  to its operating rotational rate, or nearly so, in act or operation  112 . At a minimum, however, the disk  16  should be spinning at least as fast as is required to fly the slider  24 . Preferably, the air flow through the plurality of apertures  48  in act or operation  112  is sufficient to lift the tab  80  completely off of the straight segment  50  of the ramp  40 . However, even if the air flow is not sufficient to lift the tab  80  completely off of the straight segment  50 , any air flow at all will provide some benefit by reducing the contact force between the tab  80  and the ramp  40 , thus reducing the rate with which contamination is generated through wear.  
         [0062]    Act or operation  114  involves pivoting the load beam  20 , including the tab  80  and the slider  24  attached thereto, so that the tab  80  moves from a straight segment  50  of the ramp  40  to a sloped segment  52  of the ramp  40 . Ideally, the tab  80  should be supported on an air bearing provided by the air flow through the plurality of apertures  48  as the load beam  20  is pivoted by the actuator  18 . In some embodiments, however, the air flow is only sufficient to lift the tab  80  off of the ramp  40  over a limited portion of the range of motion in act or operation  114 , and in still other embodiments the tab remains in sliding contact through the entire act or operation.  
         [0063]    Act or operation  116  involves flying the slider  24  over the surface of the disk  16  so that the tab  80  disengages from the ramp  40 . More specifically, as actuator  18  pivots the load beam  20  in the direction of the ID of the disk  16 , the tab  80  follows the contour of the ramp  40  as it moves along the sloped segment  52 . As the tab  80  nears the end of the sloped segment  52  the slider  24  comes ever closer to the surface of the disk  16  and encounters an ever increasing flow of air proximate to the surface of the disk  16 . This flow of air provides lift to the slider  24 . The lift felt by the slider  24  is transferred to the flexure  22 , the load beam  20 , and ultimately to the tab  80 .  
         [0064]    In the prior art, the lift transferred to the tab  32  had to be sufficient to overcome attractive forces tending to hold the tab  32  against the surface of the ramp  30  before the tab  32  would disengage from the ramp  30 . However, in act or operation  116  of the present invention the tab  80  is supported off of the first surface  44  by a cushion of air so that the attractive forces between the ramp  40  and the tab  80  are minimized or eliminated. Consequently, unlike the prior art, in a preferred embodiment of process  100  there is not a sharp transition at the moment when the tab  80  separates from the ramp  40 . Instead, in act or operation  116  the transition as the tab  80  disengages the ramp  40  is smooth and gradual as the slider  24  gains the necessary lift to fly over the surface of the disk  16 . In embodiments of act or operation  114  in which the tab  80  is in sliding contact with the ramp  40  at the time act or operation  116  begins, the transition in act or operation  116  may be abrupt as in the prior art. However, the lift provided to the tab  80 , even if insufficient to raise the tab  80  off of the ramp  40  prior to the end of act or operation  114 , can still reduce the magnitude of the jolt experienced by the slider  24  as the tab  80  disengages in act or operation  116 .  
         [0065]    [0065]FIG. 13 shows a flow chart illustrating the process  120  for unloading a slider  24  according to the present invention. The process  120  includes the act or operation  122  of providing a spinning magnetic disk  16  within a housing  12 , the act or operation  124  of providing an actuator  18  and a load beam  20 , where the actuator  18  is configured to pivot the load beam  20  proximate to the surface of the disk  16 , the act or operation  126  of providing a slider  24  attached to the load beam  20  that is flying over the surface of the disk  16 , the act or operation  128  of providing a tab  80  attached to the load beam that extends the load beam in a first direction, and the act or operation  130  of providing a ramp of the present invention such that the rotating disk  16  provides a flow of air through the plurality of apertures  48 . The process  100  further includes the act or operation  132  of pivoting the load beam  20  to engage tab  80  with ramp  40 , the act or operation  134  of moving the tab  80  along the ramp  40 , and the act or operation  136  of reducing the rotation rate of the disk  16 .  
         [0066]    Acts or operations  122 ,  124 , and  126  are all well known in the prior art. Act or operation  128  involves providing a tab  80  attached to the load beam  20  and is essentially the same as act or operation  108  described above. In act or operation  130  a ramp  40  of the present invention is provided, where the rotating disk  16  provides a flow of air through the plurality of apertures. The ramp  40  should be positioned as described in act or operation  110  except that the tab  80  will not be engaged with it.  
         [0067]    Act or operation  132  involves pivoting the load beam  20 , including the tab  80  and the slider  24  attached thereto, such that the tab  80  engages a sloped segment  52  of the ramp  40  as the load beam  20  is brought to the OD of the disk  16 . The flow of air through the apertures  48  can serve to cushion the engagement, gently guiding the tab  80  onto the sloped segment  52 , in contrast to the prior art in which the tab  32  simply collided with the ramp  30 . It will be appreciated by one skilled in the art that gently guiding the tab  80  onto the sloped segment  52  will tend to preserve the surface of the ramp  40  and reduce the amount of wear and contamination generated by engaging the tab  80  with the ramp  40 .  
         [0068]    Act or operation  134  is directed to moving the tab  80  over the sloped segment  52  and then onto the straight segment  50  of the ramp  40 . Ideally, the flow of air through the plurality of apertures  48  provides a lifting force to the tab  80  that is sufficient to keep the tab  80  separated from the ramp  40  by an air bearing as the tab  80  moves across sloped segment  52  and onto straight segment  50 . However, even if the lift provided to the tab  80  is insufficient to maintain a separation between the tab  80  and the ramp  40  during act or operation  134 , it can still reduce the magnitude of the contact force between them and thereby reduce wear and contamination.  
         [0069]    Act or operation  136  involves reducing the rotation rate of the disk  16 , thereby reducing the flow of air through the plurality of apertures  48  so that the lifting force experienced by the tab  80  is reduced. As the lifting force diminishes the tab  80  gently sets down on the straight segment  50  of the ramp  40 . Once the disk  16  slows sufficiently and the air flow through the plurality of apertures  48  has stopped the slider  24  is said to be parked.  
         [0070]    Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Technology Classification (CPC): 6