Abstract:
A head slider of a suspension supports a read/write head for data transfer to and from a data storage disk. A mounting structure is conventionally used for holding the suspension. A positioning finger applies a force to the suspension for and thereby positions a head slider to a static height for simulating the “flying” action of the head slider in the data storage device. A measuring device measures the static height of the head slider and transmits the same to a controller which generates a control strategy for positioning the head slider of the suspension to the fly-height. An embodiment of the invention uses a common mounting assembly for receiving a plurality of suspensions. The use of a common positioning assembly for simultaneously positioning the head sliders of the plurality of suspensions substantially reduces time consumed and improves efficiency.

Description:
FIELD OF INVENTION  
         [0001]    The present invention relates generally to a fly-height positioning apparatus. In particular, the invention relates to a fly-height positioning apparatus for positioning a head slider of a suspension at a desired fly-height.  
         BACKGROUND  
         [0002]    Suspensions are well known and commonly used within dynamic magnetic and optical information storage devices or drives. A suspension is a component which positions a magnetic read/write head over a desired position on a storage medium, for example, a rigid disk. At a free end of the suspension is a head slider for supporting the read/write head. The suspension is normally combined with an actuator arm to which a mounting region of the suspension is mounted so as to position the suspension and thus the head slider and the read/write head.  
           [0003]    The aerodynamically designed head slider enables the head slider to “fly” on an air bearing (or air layer) generated by a spinning storage disk. The “flying” action positions the head slider at a desired fly-height. The suspension is resilient to allow movements along pitch and roll axes to accommodate surface variations in the spinning storage disk. The roll axis is the longitudinal axis of the suspension and the pitch axis is perpendicular to the roll axis and the surface of the suspension.  
           [0004]    Densely packed data on the spinning storage disk requires precision in positioning the read/write head on the storage disk. Therefore, the position or attitude of the head slider as it “flies” over the storage disk is an important performance factor.  
           [0005]    When the suspension is not actually flying over a spinning storage disk, for example during suspension testing or attitude adjustment, the flying of the suspension is simulated by applying a force to the suspension to position the head slider of the suspension at a desired fly-height. The attitude of the head slider under this simulated state is termed the static attitude. The static attitude can be measured with reference to the pitch and roll axes of the suspension. A pitch static attitude and a roll static attitude are obtained when measured with reference to the pitch and roll axes respectively. Deviations from the pitch and roll static attitudes can be quantified as pitch and roll errors. A static attitude adjustment apparatus is used to interact with the suspension to rectify pitch and roll errors.  
           [0006]    The suspension is conventionally held within a mounting device of the static attitude adjustment apparatus by a finger applying a force to the suspension. The applied force bends the suspension to position the head slider at a static height. A measuring device measures the static height of the head slider and transmits the static height to a controller, which generates a control strategy for positioning the head slider of the suspension at the desired fly-height.  
           [0007]    The fly-height positioning process is time-consuming and inefficient. When a production line involves a plurality of suspensions, the total time taken to position the multiple suspensions is substantial. The need to remove and replace the suspensions from the mounting structure after the static attitude of each suspension has been adjusted further adds to the time taken.  
           [0008]    There is hence a need for a fly-height positioning apparatus for efficiently positioning a suspension or a plurality of suspensions to a desired fly-height.  
         SUMMARY OF INVENTION  
         [0009]    Therefore, in accordance with a first aspect of the invention, there is disclosed a fly-height positioning apparatus comprising:  
           [0010]    a base structure;  
           [0011]    a mounting structure being movably coupled to the base structure for displacing along an indexing axis, the mounting structure for receiving a plurality of suspensions, each suspension being elongated and planar; and  
           [0012]    an indexing actuator cooperating with the base structure and the mounting structure for positioning the mounting structure along the indexing axis relative to the base structure and thereby positioning one of the plurality of suspensions at a processing position.  
           [0013]    In accordance with a second aspect of the invention, there is disclosed a fly-height positioning method comprising the steps of:  
           [0014]    receiving a plurality of suspensions in a mounting structure, the mounting structure being movably coupled to a base structure for displacing along an indexing axis, each suspension being elongated and planar and having a mounting aperture, and the mounting structure interacting with each mounting aperture of the plurality of suspensions for gripping the suspension;  
           [0015]    providing an indexing actuator for cooperating with the base structure and the mounting structure to position the mounting structure along the indexing axis relative to the base structure; and  
           [0016]    positioning one of the plurality of suspensions at a processing position along the indexing axis by the indexing actuator communicating the base structure and the mounting structure, the suspension having a mounting region and a head slider constituting two distal ends thereof. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    Embodiments of the invention are described hereafter with reference to the following drawings, in which:  
         [0018]    [0018]FIG. 1 is a side view of a fly-height positioning apparatus according to an embodiment of the invention;  
         [0019]    [0019]FIG. 2 is a plan view of the fly-height positioning apparatus of FIG. 1;  
         [0020]    [0020]FIG. 3 is a partial side view of a mounting structure of the fly-height positioning apparatus of FIG. 1 with a first jaw and a second jaw in an open position;  
         [0021]    [0021]FIG. 4 is a partial reverse view of the fly-height positioning apparatus of FIG. 1 with a static attitude adjustment apparatus;  
         [0022]    [0022]FIG. 5 is a perspective view of the fly-height positioning apparatus of FIG. 1 with the static attitude adjustment apparatus of FIG. 4; and  
         [0023]    [0023]FIG. 6 is a partial perspective view of section “A” of FIG. 5 of the fly-height positioning apparatus of FIG. 1 with the static attitude adjustment apparatus of FIG. 4.  
     
    
     DETAILED DESCRIPTION  
       [0024]    A fly-height positioning apparatus for addressing the disadvantages of conventional fly-height positioning apparatuses is described in this section.  
         [0025]    An embodiment of the invention, a fly-height positioning apparatus  20  is described with reference to FIG. 1, which shows a side view of the fly-height positioning apparatus  20 , and FIG. 2, which shows a plan view of the fly-height positioning apparatus  20 .  
         [0026]    The fly-height positioning apparatus  20  includes a mounting structure  22  being movably coupled to a base structure  24  for displacing along an indexing axis (not shown). An indexing actuator  25  is mounted onto the base structure  24  and is for communicating with the base structure  24  to position the mounting structure  22  along the indexing axis. The indexing actuator  25  is preferably one of an electrical motor or a servomotor being coupled to the mounting structure  22  in a rack and pinion arrangement.  
         [0027]    With reference to FIG. 3, which shows a partial side view of the mounting structure  22 , the mounting structure  22  is for receiving one of a plurality of suspensions  26 . Each suspension  26  is typically elongated and planar and has a mounting region  28  and a head slider  30  constituting the two ends of the suspension  26 . The head slider  30  of the suspension  26  is for supporting a read/write head when used in a data storage medium, for example, a fixed disk drive (all not shown). The read/write head is positioned over a storage disk for data transfer to and from the storage disk.  
         [0028]    In the fixed disk drive example, the aerodynamically designed head slider  30  enables the head slider  30  to “fly” on an air bearing generated by a spinning storage disk. The “flying” action positions the head slider  30  at a fly-height. The suspension is resilient to allow movements along pitch and roll axes to accommodate surface variations in the spinning storage disk. The roll axis is a longitudinal axis of the suspension  26  and the pitch axis is perpendicular to the roll axis and the surface of the suspension  26 .  
         [0029]    The mounting structure  22  includes a first jaw  32  and a second jaw  34  arranged for displacing in opposing directions along a vertical axis (not shown) between an open and a close position (not shown). FIG. 3 shows the first jaw  32  and the second jaw  34  in an open position. Each of the first jaw  32  and the second jaw  34  has a clamping face  36 / 37 . The clamping face  36  of the first jaw  32  and the clamping face  37  of the second jaw  32  are inward-facing. The vertical axis is perpendicular to the indexing axis and the planar surface of the mounting region  28  of the suspension  26 .  
         [0030]    With reference to FIG. 1, FIG. 2 and FIG. 3, a plurality of datum pins  38  are positioned on the clamping face  36  of the first jaw  32  and extend perpendicularly from the clamping face  36  of the first jaw  32 . A protrusion  40  is formed at a free end of each datum pin  38 . Each protrusion  40  is inserted into and inlaid within a corresponding cavity (not shown) formed on the clamping face  37  of the second jaw  34  when the first jaw  32  and the second jaw  34  are engaged in the close position. Each suspension  26  has a mounting aperture (not shown) formed at the mounting region  28  which is shaped and sized to allow the protrusions  40  of the datum pins  38  to pass through. Both the protrusions  40  and the datum pins  38  are preferably cylindrical, with the datum pins  38  diametrically greater than the protrusions  40 . When the suspension  26  is mounted onto the protrusions  40  of the datum pins  38 , the first jaw  32  and the second jaw  34  are positioned in the close position for the datum pins  38  and the clamping face  37  of the second jaw  34  to correspondingly abut two outwardly facing surfaces (not shown) of the suspension  26  and thereby grip the suspension  26 .  
         [0031]    Each datum pin  38  is movably mounted to the first jaw  32  and is supported by a spring (not shown) within the first jaw  32 . The spring resiliently biases the free ends of the datum pins  38  away from the clamping face  36  of the first jaw  32 , allowing the mounting structure  22  to accommodate suspensions  26  of various thickness.  
         [0032]    The mounting structure  22  includes a cartridge  50  with a plurality of recesses (not shown) spaced apart on a surface of the cartridge  50 . The recesses (not shown) are shaped and sized to receive the mounting region  28  of the suspension  26 . Each recess (not shown) has a conduit (not shown) with a central axis in the cartridge  50 . The conduits coincide with the center of the mounting aperture of the suspension  26  to allow the corresponding datum pins  38  to pass through. The cartridge  50  allows a plurality of suspensions  26  to be arranged in a row before the cartridge  50  is mounted onto the mounting structure  22 , so that the suspensions  26  can be readily gripped by the corresponding datum pins  38 . The cartridge  50  can be easily mounted and dismounted from the mounting structure  22  by using locating elements. The first jaw  32  further displaces away from the second jaw  34  along a forward axis (not shown) to allow easy access when a user mounts or dismounts the cartridge  22 . A retraction actuator  54  interacts with the first jaw  32  for displacing the first jaw  32  along the forward axis. The retraction actuator  54  is preferably a cylinder-type pneumatic actuator.  
         [0033]    The fly-height positioning apparatus  20  also includes an alignment assembly  60  and a lifting assembly  62 . The alignment assembly  60  comprises a plurality of pins  64  spaced along and extending from the alignment assembly  60 . Each pin  64  corresponds to one of the suspensions  26  and is for insertion into an alignment aperture  66  on the suspension  26 . The alignment aperture  66  is located on the suspension  26  between the mounting aperture and the head slider  30 . When inserted into the alignment aperture  66 , the pin  64  immobilizes the suspension and thereby substantially prevents movement of the suspension  26  about the central axis of the mounting aperture.  
         [0034]    The lifting assembly  62  comprises a plurality of stubs  68  spaced apart, with each stub  68  corresponding to one of the suspensions  26 . The lifting assembly  62  displaces along the vertical axis for abutting a free end of the stub  68  onto a flexure portion (not shown) of the suspension  26  thereby bending the suspension  26 . The flexure portion of the suspension  26  is proximate to the head slider  30 . The lifting assembly  62  is for lifting the head slider  30  of each of the suspensions  26  to a static height (not shown) relative to the mounting region  28  of the suspension  26 .  
         [0035]    The first jaw  32 , the second jaw  34 , the alignment assembly  60 , and the lifting assembly  62  displaces relative to each other along the vertical axis. A plurality of cams  69 , each with a different cam profile, interact with, and position the first jaw  32  and the second jaw  34  in the open or close positions, the alignment assembly  60  along the vertical axis and the lifting assembly  62  along the vertical axis. A cam  69  is mounted onto a positioning actuator  70  for controlling the rotational displacement of the cam  69 . The positioning actuator  70  is preferably a servomotor.  
         [0036]    The indexing actuator  25 , the retraction actuator  54  and the positioning actuator  70  are electrically connected to a controller (not shown). The controller controls the indexing actuator  25  to position the mounting structure  22  along the indexing axis, which in turn positions the suspension  26  at a processing position (not shown). The fly-height positioning apparatus  20  further includes a measuring device (not shown) for measuring the static height of the head slider  30  of the suspension  26  positioned at the processing position.  
         [0037]    When the suspension  26  is not actually flying over a spinning disk as described in the aforementioned fixed disk drive example, the fly-height of the head slider  30  is simulated by applying a force to the suspension  26 . The simulation is achieved by the lifting assembly  62  interacting with the suspension  26  to position the suspension  26  at the fly-height. The attitude of the head slider in this simulated state at the fly-height is termed the static attitude. The static attitude can be measured with reference to pitch and roll axes of the suspension  26 . A pitch static attitude and a roll static attitude is obtained when measured with reference to the pitch and roll axes respectively.  
         [0038]    Deviations from the pitch and roll static attitudes are caused by manufacturing variations in the suspension  26 , handling of the suspension  26  and other factors arising during or after manufacturing. With reference to FIG. 4, FIG. 5 and FIG. 6, a static attitude adjustment apparatus  74  is positioned and aligned for adjusting the static attitude of the suspension  26  positioned at the processing position. FIG. 4 and FIG. 5 show a partial reverse view and a perspective view respectively of the fly-height positioning apparatus  20  with the static attitude adjustment apparatus  74 , and FIG. 6 shows a partial perspective view of section “A” of FIG. 5 of the fly-height positioning apparatus  20 . Both the measuring device (not shown) and the static attitude adjustment apparatus  74  are electrically connected to the controller.  
         [0039]    The controller ascertains if there is any height difference between the measured static height received from the measuring device (not shown) and a fly-height predetermined by a user. The controller then generates a control strategy based on the height difference to control the positioning actuator  70  and the rotational displacement of the cam  69 , thereby positioning the head slider  30  at the fly-height.  
         [0040]    The iterative nature of using an algorithm, such as a binary search algorithm, to generate the control strategy is time-consuming. Obtaining the static height using the measuring device (not shown) as a parameter for the control strategy, and the execution, of the control strategy by the lifting assembly  62  further adds to the time taken to position the head slider  30  at the fly-height.  
         [0041]    This greatly reduces efficiency when positioning the fly-height for a plurality of suspensions  26  along, for example, a production line. The fly-height positioning apparatus  20  however concurrently positions the head sliders  30  of a plurality of suspensions  26  along the vertical axis.  
         [0042]    As an example of a fly-height positioning method, three suspensions  26  are received within the mounting structure  22 . Initially, the first suspension  26  is positioned at the processing position. When the lifting assembly  62  positions the head slider  30  of the first suspension  26  at the fly-height based on the static height measured by the measuring device (not shown), the head sliders  30  of the second and third suspensions  26  are consequently positioned at a static height proximate to the required fly-height. After the static attitude of the first suspension  26  is adjusted by the static attitude adjustment apparatus  74 , the indexing actuator  26  positions the mounting apparatus  28  along the indexing axis for removing the first suspension  26  from and consequently positioning the second suspension  26  at the processing position. The head slider  30  of the second suspension  26  is already positioned at the fly-height when the second suspension  26  is positioned at the processing position. This reduces the need for further reiterative positioning of the head slider  30  of the second suspension  26  using the algorithm-based control strategy.  
         [0043]    Alternatively, the static attitude of the head slider  30  of the second suspension is measured by the measuring device (not shown) when the second suspension  26  is positioned at the processing position. However, the previous positioning of the head slider  30  of the first suspension  26  greatly reduces the height difference between the static height of the head slider  30  of the second suspension  26  and the fly-height. This greatly reduces the time required for positioning the head slider  30  of the second suspension at the fly-height by reducing the number of iterations required for generating the control strategy.  
         [0044]    When the third suspension  26  is subsequently positioned at the processing position, the time  25  required for positioning the head slider  30  of the third suspension  26  at the fly-height is further reduced. Furthermore, the cartridge  50  used in the mounting structure  22  eliminates the need to remove and replace a suspension  26  from the mounting structure after each static attitude adjustment process for each suspension  26 . The ability to pre-load and pre-align a plurality of suspensions  26  onto the cartridge  50  further eliminates redundant in-situ processes along a production line. Therefore, the fly-height positioning apparatus  20  clearly improves the efficiency of not only the fly-height positioning process for a plurality of suspensions  26 , but also the static attitude adjustment process for the plurality of suspensions  26 .  
         [0045]    The fly-height positioning apparatus  20  described in this section utilizes an embodiment of the invention to illustrate how the disadvantages of conventional fly-height positioning apparatus and methods are addressed. Although only one embodiment of the invention is disclosed, numerous modifications can be made to the embodiment without departing from the scope and spirit of the invention.