Abstract:
A disc drive includes a base, at least one disc rotatably attached to the base, and an actuator assembly rotatably attached to base and supporting a slider and a transducer at a distal end thereof. The slider and transducer are positioned to be in transducing relation with respect to the disc. An air dam is positioned over the disc and near an arc through which the slider and transducer are rotated. The air dam is positioned so as to produce an area of high pressure substantially about an area including a portion of the arc through which the slider and transducer are rotated. Surfaces are aligned with and extend in a coplanar relationship with the disc to transfer an outwardly directed airflow away from the disc without impinging turbulent flow on or at the disc edge.

Description:
RELATED APPLICATIONS 
     This is a continuation-in-part application of the U.S. patent application Ser. No. 09/894,668 filed Jun. 27, 2001 which is based on the provisional application No. 60/220,722 filed Jul. 26, 2000, and is also a continuation-in-part of the U.S. patent application Ser. No. 09/901,318 filed Jul. 9, 2001 abandon which is based on the provisional application No. 60/235,613 filed Sep. 27, 2000 and the provisional application No. 60/277,782 filed Mar. 21, 2001. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the field of data storage devices. More particularly, but not by way of limitation, this invention relates to an apparatus and method for controlling the aerodynamic excitation imparted to disc drive components by airstreams generated by spinning discs in a disc drive. 
     BACKGROUND OF THE INVENTION 
     One key component of any computer system is a device to store data. Computer systems have many different places where data can be stored. One common place for storing massive amounts of data in a computer system is on a disc drive. The most basic parts of a disc drive are an information storage disc that is rotated, an actuator that moves a transducer to various locations over the disc, and electrical circuitry that is used to write and read data to and from the disc. The disc drive also includes circuitry for encoding data so that it can be successfully retrieved and written to the disc surface. A microprocessor controls most of the operations of the disc drive as well as passing the data back to the requesting computer and taking data from a requesting computer for storing to the disc. 
     The transducer is typically placed on a small ceramic block, also referred to as a slider, that is aerodynamically designed so that it flies over the disc. The slider is passed over the disc in a transducing relationship with the disc. Most sliders have an air-bearing surface (“ABS”) which includes rails and a cavity between the rails. When the disc rotates, air is dragged between the rails and the disc surface causing pressure, which forces the head away from the disc. At the same time, the air rushing past the cavity or depression in the air bearing surface produces a negative pressure area. The negative pressure or suction counteracts the pressure produced at the rails. The slider is also attached to a load spring which produces a force on the slider directed toward the disc surface. The various forces equilibrate so the slider flies over the surface of the disc at a particular desired fly height. The fly height is the distance between the disc surface and the transducing head, which is typically the thickness of the air lubrication film. This film eliminates the friction and resulting wear that would occur if the transducing head and disc were in mechanical contact during disc rotation. In some disc drives, the slider passes through a layer of lubricant rather than flying over the surface of the disc. 
     Information representative of data is stored on the surface of the storage disc. Disc drive systems read and write information stored on tracks on storage discs. Transducers, in the form of read/write heads attached to the sliders, located on both sides of the storage disc, read and write information on the storage discs when the transducers are accurately positioned over one of the designated tracks on the surface of the storage disc. The transducer is also said to be moved to a target track. As the storage disc spins and the read/write head is accurately positioned above a target track, the read/write head can store data onto a track by writing information representative of data onto the storage disc. Similarly, reading data on a storage disc is accomplished by positioning the read/write head above a target track and reading the stored material on the storage disc. To write on or read from different tracks, the read/write head is moved radially across the tracks to a selected target track. 
     The methods for positioning the transducers can generally be grouped into two categories. Disc drives with linear actuators move the transducer linearly generally along a radial line to position the transducers over the various tracks on the information storage disc. Disc drives also have rotary actuators which are mounted to the base of the disc drive for arcuate movement of the transducers across the tracks of the information storage disc. Rotary actuators position transducers by rotationally moving them to a specified location on an information recording disc. A rotary actuator positions the transducer quickly and precisely. 
     The actuator is rotatably attached to a shaft via a bearing cartridge which generally includes one or more sets of ball bearings. The shaft is attached to the base and may be attached to the top cover of the disc drive. A yoke is attached to the actuator and is positioned at one end of the actuator. The voice coil is attached to the yoke at one end of the rotary actuator. The voice coil is part of a voice coil motor which is used to rotate the actuator and the attached transducer or transducers. A set of permanent magnets is attached to the base and cover of the disc drive. The voice coil motor which drives the rotary actuator comprises the voice coil and the permanent magnet. The voice coil is attached to the rotary actuator and the permanent magnet is fixed on the base. A top plate and a bottom plate are generally used to attach the set of permanent magnets of the voice coil motor to the base. The top plate and the bottom plate also direct the flux of the set of permanent magnets. Since the voice coil sandwiched between the set of permanent magnets and top plate and bottom plate which produces a magnetic field, electricity can be applied to the voice coil to drive it so as to position the transducers at a target track. 
     One problem associated with disc drives is that the actuator assembly may resonate or vibrate at certain frequencies which in turn causes the transducer within the slider to move off-track. In other words, if there is even a slight vibration, the slider may move away from the center of a track during a track following operation. If the vibration is too large, the transducer continuously crosses the track to be followed and little if any information can be read. Writing can not be accomplished since there is a risk, at these times, that the transducer may be positioned over another adjacent track and attempting to write may result in overwriting other data that is necessary. The source of vibration may be the natural resonance of an actuator assembly or may be due to other influences. One of these influences is airflow generated by the rotating discs. The airflow generated by the rotating disc or discs (also referred to as windage) excites head suspensions which in turn cause the slider and transducers to vibrate. The vibration causes run-out which is off-track motion. Of course as the density of tracks is increased, run-out due to smaller vibrations becomes more critical. 
     What is needed is a disc drive that reduces vibration of the suspension and attached transducer and slider resulting from airflow between the spinning discs in a disc drive. What is also needed is a disc drive in which there is less off-track motion or run-out. There is a constant need for a disc drive which has additional capacity as well as increased reliability without an appreciable rise in the error rate. There is also a need for methods and apparatus to reduce vibrations in the suspension and attached slider and transducer. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention are directed to providing an air stream conditioning apparatus for a disc drive for damping the aerodynamic excitation of an air stream or fluid flow on disc drive components. The disc drive typically has an enclosure supporting a rotating disc and moveably supporting an actuator having a distal end moving a data transfer element in a data transfer relationship with a data storage surface of the data disc. In one aspect of the present invention the flow conditioning apparatus comprises one or more first extensions pivotable with respect to one or more second extensions. The flow conditioning apparatus is supportable downstream of the actuator with respect to the flow currents. The flow conditioning apparatus provides a second extension extending substantially radially from an outer edge of the disc to an inner edge of the disc, adjacent the disc surface. Embodiments of the present invention provides for the flow conditioning apparatus to be changeable between a compact configuration and an operational configuration. 
     In another aspect of the invention, the flow conditioning apparatus includes a shroud surface substantially transverse to the disc surface, at a far side of the first extension. The first extension may include flat surfaces substantially coextensive with the disc surfaces, or may integrate ramps for lifting the sliders away from the disc surfaces. 
     Embodiments of the present invention provide for a way to reduce the pressure difference across the actuator and decelerate the fluid flow impinging on the actuaton. In addition, high frequency fluid flow disturbances can be redistributed outside the servo bandwidth where the servo capability of the disc drive is better equipped to effectively deal with the disturbance. The present invention therefore provides the advantage of reducing windage induced non-repeatable run-out. 
     These and various other features as well as advantages which characterize the present invention will be apparent upon reading of the following detailed description and review of the associated drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a disc drive in which several discs have been removed to show an actuator and a flow conditioning apparatus according to one embodiment of the present invention. 
         FIG. 2  is an isometric view of the flow conditioning apparatus in an unfolded or operational configuration. 
         FIG. 3  is an isometric view of the flow conditioning apparatus in a folded or compact configuration. 
         FIG. 4  is a flow chart showing a process for assembling the flow conditioning apparatus in a disc drive. 
         FIG. 5  is a top view of the disc drive of  FIG. 1 . 
         FIG. 6  is a top view of a disc drive with a flow conditioning apparatus having a shroud. 
         FIG. 7  is a side view of a flow conditioning apparatus according to another embodiment of the present invention. 
         FIG. 8  illustrates a side view of the flow conditioning apparatus with an alternative mounting feature. 
         FIG. 9  is an enlarged view showing features for positively positioning the flow conditioning apparatus of  FIG. 7  in the operational configuration. 
         FIG. 10  is an isometric view of a flow conditioning apparatus with an integrated ramp. 
         FIG. 11  is a top view showing the flow conditioning apparatus of  FIG. 10  assembled in a disc drive. 
         FIG. 12  is a flow chart illustrating a method of assembling the flow conditioning apparatus of  FIG. 10  to a disc drive. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  is an isometric view of a disc drive  100  according to one embodiment of the present invention. The disc drive  100  includes a base plate or base  102 , and a cover  104 . The base  102  and cover  104  form a disc drive enclosure. Mounted to the base  102  is a spindle motor  106  to which several discs  110  are secured. Each disc  110  is generally annular in shape, with an inner edge  112  and an outer edge  114  circumscribing two opposing disc surfaces  116  (of which only one is visible in the drawing) to which data can be stored for later retrieval. The base  102  provides a cavity or room for the discs  110  to be seated in a substantially coaxial arrangement, with an inner wall  118  of the base running around the outer edges  114  of the discs  110 , substantially transverse to the disc surfaces  116 . 
     In the drawing, several of the discs  110  have been removed to provide a clearer illustration of an actuator assembly  120  that is pivotably mounted to the base. On one side of the pivot  121 , the actuator assembly  120  includes a plurality of arms  122  to which are attached load beams or suspensions  124 . At the end of each suspension  124  is a slider  126  that carries the read/write devices (designated generally by  128 ). The present invention is equally applicable to sliders having different types of read/write devices, such as what is generally referred to as transducers, magneto resistive heads or giant magneto resistive heads. On another side of the pivot, the actuator assembly  120  extends to support a voice coil  130  next to one or more magnets  132  fixed relative to the base  102 . When energized, resultant electromagnetic forces on the voice coil  130  causes the actuator assembly  120  to rotate about the pivot  121 , thereby bringing the read/write devices into various radial locations relative to the disc surfaces  116 . It can be seen that, with the spindle motor  106  rotating the discs  110 , for example, in a direction indicated by arrow  140 , and the actuator assembly  120  moving the read/write heads  128  in an arcuate path, as indicated by arrow  142 , across the disc surfaces  116 , various locations on the disc surfaces  116  can be accessed by the read/write heads for data recordation or retrieval. 
     As the discs  110  are rotated, fluid or air adjacent to the disc surfaces  110  is also brought into motion, generating air streams or flow currents in the disc drive enclosure. A flow conditioning apparatus  300  is provided adjacent the discs  110  to modify or improve the flow behavior and characteristics of the flow currents, as well as to exploit the flow currents to improve the overall performance of the disc drive. The flow conditioning apparatus  300  includes a set of fins or first extensions  310  pivotable with respect to a set of vanes or second extensions  330 . 
     Referring to  FIG. 2 , one embodiment of the flow conditioning apparatus  300  will be described in more detail. The flow conditioning apparatus  300  includes a set of first extensions  310 , a pivot  320 , and a set of second extensions  330 . Each first extension  310  can be generally described as having a proximal end  312  and a distal end  314  relative to the pivot  320 . 
     From the proximal end  312  to the distal end  314 , the first extension  310  includes two opposing flat surfaces  316  (of which only one is visible in the drawing). The first extension  310  is configured such that, in assembly, the flat surfaces  316  are substantially parallel to the disc surfaces  116 , as shown in  FIG. 1 . The first extension  310  has a near side  318  running substantially from the proximal end  312  to the distal end  314 . In assembly, the near side  318  will be arranged next to the outer edge  114  of a disc  110 . In this embodiment, the near side  318  is slightly curved to follow the curvature of the outer edge  114  of the disc  110 . Optionally, as illustrated here, the flat surface  316  is of variable width along the length of the first extension  310 , with an intermediate portion  313  that is wider than either the proximal end  312  or the distal end  314 . The first extensions  310  are formed to be of fixed spatial relation to one another, and are unitary with a first joint portion  322 . The first extensions  310  may have the same thickness or substantially the same thickness as the discs  110 . The number of first extensions  310  in the flow conditioning apparatus  300  preferably equals the number of discs  110  in the disc drive  100 . For example, if the disc drive configuration calls for only one disc  110 , the flow conditioning apparatus  300  may be formed with only one first extension  310 . The first extensions  310  change the boundary conditions at the outer edges  114  of the discs  110  when assembled in close proximity to the discs, and essentially reduce turbulent flow conditions at or off the outer edges  114  of the discs. 
     Continuing with  FIG. 2 , the flow conditioning apparatus includes a set of second extensions  330 , each of which are in fixed spatial relation to one another, and are unitary with a second joint portion  324 . In this particular embodiment, the first joint portion  322  is substantially annular in shape, and designed to be located co-axially with the second joint portion  324  which is also substantially annular in shape. A fastener  326  is threaded through the first joint portion  322  and the second joint portion  324  to provide the pivot  320 . The fastener  322  may serve an additional function of engaging an appropriate receiver at the base  102 , such as a threaded hole, and thereby be used for securing the flow conditioning apparatus  300  to the base  102 . Variations to the pivot  320  may be made to allow for free, stepped or controlled rotation of the second extensions  330  relative to the first extensions  310 . 
       FIG. 2  shows the flow conditioning apparatus  300  in an unfolded or operational configuration  302  where the second extensions  330  are angularly displaced from the first extensions  310 . In one application, such as that shown in  FIG. 1 , while the first extensions  310  are located alongside the outer edges  114  of the discs  110  in a generally circumferential orientation, the second extensions  330  are directed in a generally radial orientation such that the second extensions  330  extend from the outer edges  114  toward the inner edges  112  of the discs. Alternatively, the second extensions  330  may be oriented such that the second extensions  330  and the first extensions  310  define an obtuse angle of displacement. In the operational configuration  302 , the second extensions  330  may be positioned above the top-most disc  110  as well as between each of the discs  110 . The number of second extensions  330  is generally one more than the number of discs  110  in the disc drive  100 . Alternatively, the flow conditioning apparatus  300  may have only one second extension  330  that is adjacent the only disc surface  116  intended for data storage. The second extensions  330  are shaped to hinder flow currents that are generated by the spinning discs  110 . Each second extension  330  therefore presents a leading side  332  to the on-coming flow currents, and a trailing side  334  ( FIG. 2 ). Optionally, the leading side  332  may be a curved surface so that, in assembly, the slider  126  will be generally the same distance away from the leading side  332  for various radial positions of the slider  126 . Alternatively, the leading side  332  may be a substantially planar surface so that the slider  126  will be nearer the leading side  332  the nearer the slider is to the outer edges  114  of the discs  110 . 
       FIG. 3  shows the flow conditioning apparatus  300  in a folded or compact configuration  304  where the second extensions  330  and the first extensions  310  are rotated relative to each other until a compact shape for the flow conditioning apparatus is achieved. In the compact configuration  304 , the second extensions  330  and the first extensions  310  substantially overlap or are interleaved to form alternating layers of second extensions  330  and first extensions  310 . Abutment features  340 ,  342  may be provided to limit the extent of rotation of the second extensions  330  relative to the first extensions  310 . Features may be included to provide access to the second extensions  330  when the flow conditioning apparatus  300  is in the compact configuration  304  so as to facilitate the change from the compact configuration  304  to the operational configuration  302 . In this example, the first extensions  310  are shaped with notches or cavities  317  that expose the second extensions  330 . Alternatively, the top-most second extension  330  may be arranged above the top-most first extension  310 , and can thus be easily accessed and pushed out from the compact configuration  304  to the operational configuration  302 . 
     Without the made-for-manufacturing advantages provided by the present invention, it would have been more difficult to assemble a part or a sub-assembly that is intended to interleave the discs  110 . More room on the base  102  would have been required, and greater care would have been required to ensure that the discs  110  are not injured in the course of assembly. 
     With the present invention, however, the compact configuration  304  allows the flow conditioning apparatus  300  to be more easily installed while demanding much less room for installation. In an exemplary assembly process  400  illustrated by the flow chart of  FIG. 4 , the spindle motor  106  and discs  110  are assembled with the base  102  of the disc drive  100  (step  402 ). The actuator assembly  120  is attached to the base  102  and merged with the discs  110 , that is, the sliders  126  are brought towards the inner edges  112  of the discs  110  and parked at a landing zone  134  (step  404 ). The flow conditioning apparatus  300  in its compact configuration  304  is then attached to a base  102  such that the first extensions  310  are in a desired orientation (step  406 ). Next, the second extensions  330  are pivoted with respect to the first extensions  310  until the flow conditioning apparatus  300  is in a desired operational configuration  302  (step  408 ). Having a compact configuration  304  and an operational configuration  302  allows the flow conditioning apparatus  300  to be placed within the disc drive  100  with minimal change from current manufacturing practices. In addition to other advantages, the present invention reduces the likelihood of accidental damage to the discs  110  since each second extension  330  approaches the discs  110  only after it is at an elevation (with respect to the base  102 ) that is between discs, or above or below a disc. The present invention also facilitates automated assembly, which can be an important factor in overall cost efficiency in manufacture. 
     When the discs  110  are spinning, the flow conditioning apparatus  300  produces a high pressure region  502  next to the leading side  332  of the second extension  330 , as schematically depicted in  FIG. 5 . On the trailing side  334  of the second extension  330 , a low pressure region  504  will be developed as the result of the flow conditioning apparatus  300 . The terms “high pressure” and “low pressure” are intended to be understood as being relative to the pressure in a similar system that does not use a flow conditioning apparatus  300  of the present invention. Further, the high pressure region  502  and the low pressure region  504  as drawn in  FIG. 5  are merely rough schematics and intended to aid understanding of the present invention, and may differ for different embodiments of the present invention and for different disc drive configurations in which the embodiment is implemented. 
     Alternatively described, the velocity of flow currents is reduced when the flow currents come up against the leading side  332  of the second extensions  330 . The second extensions  330  may be sized to substantially fill the space between adjacent discs  110 . In such a fashion, the slider  126  with its associated read/write devices  128  can be made to operate in a high pressure region  502  created by the flow conditioning apparatus  300 , and thus operate within a stable region that is less prone to vibration resulting from the flow currents. In addition, the velocity of flow currents within the disc drive  100  and away from the flow conditioning apparatus  300  may be reduced, thus stabilizing the slider  126  and the read/write devices  128 . Another way to consider the effect of the flow conditioning apparatus  300  would be that there is less energy in the flow currents and therefore less energy to impart vibrations on various components of the disc drive  100 . For example, torque disturbances on the actuator assembly  120  are reduced. Accordingly, the extent of vibration-induced run-out errors decreases, leading to an overall improved performance of the disc drive  100 . 
     The present invention may be further exploited to create an environment favorable for efficient application of a breather filter  510 . Air may sometimes enter a disc drive. Rather than have unfiltered air enter the disc drive  100  and contaminate its internal environment, a breather filter  510  is incorporated with the disc drive  100  so that any air that enters the disc drive  100  is first filtered. The present invention provides for known locations where low pressure regions  504  will develop, and thereby provide a desirable location for the breather filter such that any air that enters the disc drive  100  would tend to enter through the breather filter  510  instead of through other openings that may not provide for filtration. As shown  FIG. 5 , on the trailing sides  334  of the second extensions  330 , low pressure regions  504  develop when the discs  110  are spinning. A breather filter  510  may be located so that its internal opening  512  opens to a low pressure region  504  that develops at the trailing side  334  of the second extension  330 , as shown. Such a breather filter  510  may be located at the base  102  or at the cover  104  of the disc drive, and would include an external opening  514  with a filter  516  interposed between the internal opening  512  and the external opening  514 . Alternatively, the external opening  514  and the internal opening  512  may be the same hole, and the filter  516  may be located to cover the internal opening  512 , and thereby be in the position to filter any incoming air. Alternatively, the breather filter  510  may include an air channel  518  leading from the external opening  514  to the internal opening  512 . 
       FIG. 6  is a top view of an alternative embodiment of the present invention, showing the flow conditioning apparatus having at least one shroud surface  640 . As in the embodiment described above, the flow conditioning apparatus  600  includes one or more first extensions  610  pivotably connected to one or more second extensions  630 . In an operational configuration  602 , the second extensions  630  are angularly displaced from the first extensions  610 . In a disc drive  100 , the second extensions  630  are directed generally radially with respect to the discs while the first extensions are disposed to one side of the discs  110 . The near side  618  of each first extension  610  is located next to the outer edges  114  of the discs  110 . Stretching along the far side  619  of each first extensions is a shroud surface  640  that is disposed substantially transverse to the disc surfaces  116 . The shroud surface  640  extends substantially from a proximal end  612  of the first extension  610  to a distal end  614  of the first extension  610 . Between the near side  618  and the shroud surface  640 , the first extension provides two opposing and substantially flat surfaces  616  that, optionally, gradually increases in width. In other words, the shroud surface  640  leads away from the near side  618  as it extends away the proximal end  612  towards the distal end  614 . By closely fitting the shroud surface  640  to the outer edge  114  of the disc  110  at the proximal end  612 , the flow currents are prevented from leaving the discs  110 . By increasingly widening the width of the flat surfaces  616 , the shroud  640  channels the flow currents away from the slider  126  and the read/write devices  128  before they are allowed to be expelled from the discs  110  in the direction indicated by arrow  642 . The provision of the shroud  640  encourages laminar flow currents and reduces aerodynamic excitation from turbulent flow currents. Shrouding also minimizes the effects of shedding vortices at the outer edges  114  of the discs  110  that may produce axial forces on the discs  110 . At the same time, shrouding reduces resistive drag on the spinning discs  110 , and thus reduces the power required to maintain the discs  100  at a desired rotational speed. 
     The present invention may be implemented in a disc drive  100  where it is desired to provide as extensive a shroud as practicable around the discs  110 . The flow conditioning apparatus  600  with the shroud  640  may therefore be used to reduce the opening in the main shroud (provided by the inner wall  118  of the base  102 ) so that the break in the overall shroud is just wide enough to provide minimal clearance for movement of the actuator assembly  120 . 
     In an alternative embodiment of the present invention, as shown in the elevation view of  FIG. 7 , the flow conditioning apparatus  700  includes second extensions  730  pivotally joined to first extensions  710 , where the first extensions are supported by a frame  770 . The frame  770  is formed at the far sides  719  of the first extensions  730  with one wall of the frame providing a shroud surface  740  along the far sides  719 . The frame further provides a cavity within which a filter cartridge  772  may be received. Optionally, the frame may be provided with one or more locating tabs  774  for alignment with corresponding apertures in the base  102 . A spring  776  cantilevered from the frame  770  has an enlarged portion  778  for pressingly engaging the cover  104  when the cover  104  is attached to the base  102 . In such a manner, the flow conditioning apparatus  700  may be assembled in the disc drive  100  without the need for threaded fasteners, thereby improving the efficiency of the manufacturing process. 
       FIG. 8  illustrates a side view of the flow conditioning apparatus  700  with an alternative mounting feature. The pivot  720  that provide for rotation of the second extensions  730  relative to the first extensions  710  includes a shaft  780 . The shaft  780  can be provided with a longitudinal opening that receives a boss  782  supported by or formed as part of the base  102 . A tool feature  784  can be provided for releasably engaging an assembly tool for rotating the shaft  780  so that the flow conditioning apparatus  700 , while assembled in its compact configuration, may be easily set into its operational configuration. 
     A number of design-for-manufacturability features can be provided, for example, features that generally positively position the flow conditioning apparatus  700  in the compact configuration or in the operational configuration.  FIG. 9  is an enlarged view of a flow conditioning apparatus  700  according to one embodiment of the present invention. The first extensions  710  and the second extensions  730  engage at a pivot  720 . The second extensions  730  include an extending portion  750  that engages a selected portion  752  of the base  102  to prevent further rotation after the flow conditioning apparatus  700  has reached its operational configuration. 
     Another design-for-manufacturability feature provides for positively retaining the flow conditioning apparatus  700  in the operational configuration. In  FIG. 9 , for example, the flow conditioning apparatus  700  further includes an extending spring member  760 . The spring member  760  is formed with a detent  761 . The second extension  730  includes a tab  766  that is received within the detent  761  at the proximal end  712  of the first extension  710 . Rotation of the second extensions  730  towards the operational configuration causes the tab  766  to engage and deflect the spring member  760 . In the operational configuration, tab  766  is retained within the detent  761  as the spring member  760  returns to pressingly engage against the tab  766 . 
     In yet another embodiment of the present invention, the flow conditioning apparatus  800  includes an integrated ramp  880 , as shown in  FIG. 10 . The first extensions  810  include near sides  818  that are sloped away from the discs so as to facilitate the lifting of the slider  126  or of an extension from the suspension  124  or slider  126 . The process  900  of assembling the flow conditioning apparatus  800  to the disc drive  100  such as that shown in  FIG. 11  may be described with reference to the flow chart of  FIG. 12 . The flow conditioning apparatus  800  is mounted to the base  102 , after which the spindle motor  106  and the discs  110  are assembled to the base  102  (steps  902 ,  904 ). The flow conditioning apparatus  800  is assembled in its compact configuration where the first extensions  810  and the second extensions  830  are substantially interleaved. The second extensions are rotated with respect to the base  102  such that they now interleave the discs  110  (step  906 ). The actuator assembly  120  is then mounted to the base  102  and merged with the ramp  880  (step  908 ). Alternatively, the order of assembling the flow conditioning apparatus  800 , the spindle motor  106  with the discs  110  and the actuator assembly  120  may be rearranged. This flexibility is another advantage particularly beneficial to the design of manufacturing assembly lines provided by the present invention. 
     Referring again to  FIG. 10 , the flow conditioning apparatus  800  may alternatively include a post  882 , a lower end of which is adapted to fit an opening in the base  102 . The engagement between the post  882  and the base  102  may be such that the flow conditioning apparatus  800  is pivotable relative to the base  102 . At the pivot  820  between the first extensions  810  and the second extensions  830 , there may be provided an opening  884  for receiving a fastener  886 . The fastener  886  engages the base  102  after passing through the opening  884 , thereby securing the orientation of the first extensions  810  with respect to the base  102 . 
     Alternatively described, one embodiment of the present invention provides a flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) for use in a disc drive (such as  100 ). The flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) has a first extension (such as  310 ,  610 ,  710 ,  810 ) defining a first plane and a second extension (such as  330 ,  630 ,  730 ,  830 ) pivotably connected to the first extension. The second extension (such as  330 ,  630 ,  730 ,  830 ) is rotatable about an axis (such as  320 ,  620 ,  720 ,  820 ), in a second plane that is substantially parallel to the first plane. 
     According to one embodiment, the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) may have a plurality of the first extensions (such as  310 ,  610 ,  710 ,  810 ) interleaved with a plurality of the second extensions (such as  330 ,  630 ,  730 ,  830 ) along the axis. The second extensions (such as  330 ,  630 ,  730 ,  830 ) may fit between the respective first extensions (such as  310 ,  610 ,  710 ,  810 ) when the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is in a folded configuration, and be positioned away from the first extensions (such as  310 ,  610 ,  710 ,  810 ) when the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is in an operational configuration (such as  302 ). There may be a lock to bias the second extensions (such as  330 ,  630 ,  730 ,  830 ) against the first extensions such that the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is retained in the operational configuration (such as  302 ). Optionally, the second extension may have an arcuate edge (such as  332 ). 
     In another embodiment, the flow conditioning apparatus (such as  600 ) may include a shroud (such as  640 ) that defines a plane substantially transverse to the first plane, with the shroud (such as  640 ) running substantially from a proximal end (such as  612 ) of the first extension (such as  610 ) to a distal end (such as  614 ) of the first extension (such as  610 ). Optionally, the first extension (such as  610 ) is wider at the distal end ( 614 ) than at the proximal end (such as  612 ). 
     In yet another embodiment, the flow conditioning apparatus (such as  800 ) may further incorporate a ramp (such as  880 ). 
     According to one embodiment of the present invention, there is provided a disc drive (such as  100 ) having a disc (such as  110 ) configured for rotation such that fluid flow is generated by the disc (such as  110 ) when in rotation, an actuator (such as  120 ) adjacent the disc (such as  110 ), and a flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) located adjacent the disc (such as  110 ). The flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) may be described as having a first extension (such as  310 ,  610 ,  710 ,  810 ) defining a first plane and a second extension (such as  330 ,  630 ,  730 ,  830 ) that is pivotably connected to the first extension (such as  310 ,  610 ,  710 ,  810 ) for rotational movement about an axis (such as  320 ,  620 ,  720 ,  820 ). The second extension (such as  330 ,  630 ,  730 ,  830 ) is configured to be rotatable in a second plane that is substantially parallel to the first plane. In the disc drive (such as  100 ), the second extension (such as  330 ,  630 ,  730 ,  830 ) may be located downstream of the actuator (such as  120 ) with respect to the fluid flow. 
     The disc drive (such as  100 ) may include a flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) where the second extension (such as  330 ,  630 ,  730 ,  830 ) extends substantially radially from an outer radial portion (such as  114 ) of the disc (such as  110 ) to an inner radial portion (such as  112 ) of the disc (such as  110 ). Optionally, the second extension (such as  330 ,  630 ,  730 ,  830 ) is disposed substantially transverse to a distal end (such as  126 ) of the actuator (such as  120 ). Optionally, the second extension (such as  330 ,  630 ,  730 ,  830 ) has an arcuate leading edge (such as  332 ) disposed in proximity to a distal end (such as  126 ) of the actuator (such as  120 ). 
     In another embodiment, the disc drive (such as  100 ) is such that the first extension (such as  310 ,  610 ,  710 ,  810 ) extends along an outer edge (such as  114 ) of the disc (such as  110 ) in proximity to the outer edge (such as  114 ). 
     Optionally, the first extension (such as  310 ,  610 ,  710 ,  810 ) is substantially coplanar with the disc (such as  110 ). The disc (such as  110 ) may be described as including opposing disc surfaces (such as  116 ), and the first extension (such as  310 ,  610 ) may have opposing extension surfaces (such as  316 ,  616 ) substantially coextensive with respective disc surfaces (such as  116 ). 
     In yet another embodiment, the disc drive (such as  100 ) includes a plurality of the disc (such as  110 ) and a plurality of the second extension (such as  330 ,  630 ,  730 ,  830 ). In an operational configuration (such as  302 ), the second extensions (such as  330 ,  630 ,  730 ,  830 ) interleave the discs (such as  110 ). In a compact configuration (such as  304 ), the second extensions (such as  330 ,  630 ,  730 ,  830 ) may interleave the first extensions (such as  310 ,  610 ,  710 ,  810 ). Optionally, the second extensions (such as  330 ,  630 ,  730 ,  830 ) fit between the respective first extensions (such as  310 ,  610 ,  710 ,  810 ) when the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is in a compact configuration (such as  304 ), and are positioned away from the first extensions (such as  310 ,  610 ,  710 ,  810 ) when the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is in an operational configuration (such as  302 ). The disc drive (such as  100 ) may further include a lock (such as  750 ,  752 ,  760 ,  761 ,  766 ,  884 ,  886 ) to bias the second extensions (such as  330 ,  630 ,  730 ,  830 ) against the first extensions (such as  310 ,  610 ,  710 ,  810 ) such that the flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) is retained in the operational configuration (such as  302 ). 
     The disc drive (such as  100 ) may include a flow conditioning apparatus (such as  300 ,  600 ,  700 ,  800 ) that further has a shroud (such as  640 ) defining a plane substantially transverse to the first plane, with the shroud (such as  640 ) running substantially from a proximal end (such as  612 ) of the first extension (such as  610 ) to a distal end (such as  614 ) of the first extension (such as  610 ). The shroud (such as  640 ) may be nearer the disc (such as  110 ) at the proximal end (such as  612 ) than at the distal end (such as  614 ). 
     Optionally, the disc drive (such as  100 ) includes a flow conditioning apparatus (such as  800 ) of which the first extension (such as  810 ) further incorporates a ramp (such as  880 ) adapted to receive a distal end (such as  126 ) of the actuator (such as  120 ). 
     In yet another embodiment, the disc drive (such as  100 ) may include a flow conditioning apparatus (such as  700 ) that further has a filter housing (such as  770 ) connected to the first extension (such as  710 ). 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the size and placement of the flow conditioning apparatus may vary while maintaining substantially the same functionality without departing from the scope and spirit of the present invention. In addition, although the embodiments described herein are directed to an apparatus for use in a disc drive, it will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems, like data storage test or certification systems, servo track writers, or optical data storage systems, without departing from the scope and spirit of the present invention.