Abstract:
An exemplary embodiment provides for a servo-actuated, head actuator design wherein a head carriage includes one or more positional sensor location features that precisely define placement. The sensor location features are configured such that a positional sensor can be mated into a specific sensor location feature. As the head carriage is typically manufactured with great accuracy, the inclusion and placement of the sensor location features will also be extremely accurate. As a result, the location of positional sensors can be pre-defined via the head carriage design such that they will be at a precise location with respect to a magnetic head attached to the head carriage, thereby reducing variation in the location of one or more positional sensors resulting from a tape drive assembly process.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/804,225 filed on Jun. 8, 2006, which is incorporated herein by reference. 
     
     BACKGROUND 
       [0002]    Modern tape drives involve multiple, tightly spaced tracks and use closed-loop servo systems to keep read/write elements, on a magnetic head, in alignment with the tracks. As part of that closed-loop servo system, tape drives utilize a variety of positional sensors to correctly the read/write elements at a selected track. Given the tight spacing of tracks, accuracy of the positional sensors is critical. 
         [0003]    One component of a positional sensor&#39;s accuracy is the positional sensor&#39;s physical location as it is typically used in conjunction with a corresponding reference magnet. As a result, misplacement of the positional sensor can lead to inaccurate positioning of a read/write element in relation to a track on a tape. The positional sensors are typically installed on an actuator assembly that includes the magnetic head and, in a manufacturing environment, it is not uncommon to have an actuator rejection rate of several percentage points due to misplacement of the positional sensors. Due to these circumstances, methods and systems for accurately installing positional sensors on an actuator receive considerable attention. 
         [0004]    One prior art technique for accurately installing positional sensors utilizes a sensor-locating jig. Generally speaking, a jig is a device used to maintain mechanically the correct positional relationship between a piece of work and the tool or between parts of work during assembly. Using the sensor-locating jig adds another step to what is typically a very complicated production process, however. Additionally, assembly variations of the other tape drive parts can contribute to misplacement of the positional sensors. Restated, the sensor-locating jig may accurately place a positional sensor on a particular part but that part may have not been properly positioned. As a result, use of a sensor locating jig to install positional sensors is not completely optimal. 
         [0005]    Another aspect of modern tape drives is that printed circuit board (“PCB”) is typically limited due to the tape drive&#39;s small form factor. Also, connections to the PCB from various tape drive parts typically take up a considerable amount of PCB real estate. As a result, methods and systems which address these two related issues are desirable. 
         [0006]    Yet another factor that complicates tape drive manufacturing is the soldering of various parts to an actuator assembly of a tape drive. In certain actuator assembly designs, a magnetic head needs to be installed before installation of other parts that require soldering. Due to this required assembly order, there is a potential that the magnetic head may be inadvertently damaged by the soldering gun. As the magnetic head is typically the most expensive single part of a tape drive, it would desirable to eliminate soldering from the manufacturing process in order to prevent the accidental head damage. Additionally, soldering produces dangerous fumes which necessitate proper ventilation systems which further add to the cost of the manufacturing process. 
         [0007]    Additionally, several original equipment manufacturers require certified soldering which involves certification of factory workers in the art of soldering. The certification process also typically requires occasional re-certification. As a result, certified soldering increases tape drive manufacturing costs due to the extra expense required to maintain certification of factory personnel. 
         [0008]    Yet another manufacturing issue involves soldering connections to head flex cables. Typically, head flex cables are used to connect a magnetic head to the PCB. However, some actuator assembly designs require additional connections, from other parts besides the magnetic head, to be soldered to the head flex cables. The soldered connections can be problematic during later testing of the magnetic head. If the magnetic head does not pass the testing, those soldered connections need to be undone so the magnetic head, along with the head flex cables, can be removed for repair or possible replacement. After the magnetic head is repaired or a new magnetic head is procured, the connections will then need to be re-soldered. As such, soldering can introduce numerous issues to the manufacturing process even. 
         [0009]    In view of the foregoing, a need exists in the art for tape drives that address the various aforementioned issues. 
         [0010]    The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
       SUMMARY 
       [0011]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, apparatuses and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated. 
         [0012]    One embodiment by way of non-limiting example provides for a servo-actuated, head actuator design wherein a head carriage includes one or more positional sensor location features that precisely define placement. The sensor location features are configured such that a positional sensor can be mated into a specific sensor location feature. As the head carriage is typically manufactured with great accuracy, the inclusion and placement of the sensor location features will also be extremely accurate. As a result, the location of positional sensors can be pre-defined via the head carriage design such that they will be at a precise location with respect to a magnetic head attached to the head carriage, thereby reducing variation in the location of one or more positional sensors resulting from a tape drive assembly process. 
         [0013]    Other embodiments by way of non-limiting example provide for facilitating electrical interconnects between the PCB of a tape drive and one or more actuator components without the use of soldering for certain parts. In one implementation, the interconnects for the magnetic head, voice coil and a positional sensor are incorporated into a single flex circuit and corresponding connector on the PCB. In addition, the voice coil flex circuit, in one implementation, is designed to have its positive line and its negative line terminate to two pads. The two-voice coil lines from the head flex circuit also terminate to similar size pads. During assembly of the actuator, the pads of the voice coil are mated to the pads of the head flex circuit and are clamped together by a flexure clamp in one implementation or, in another implementation, clamped between a head carriage and a voice coil holder wherein the clamping force is achieve by screws holding the head carriage and voice coil motor firmly together. These implementations eliminate the need for soldering of these connections. As a result, assembly and disassembly of the assembly to and from the actuator assembly is facilitated. In addition, when the relevant fasteners are removed to disengage the head carriage from the actuator assembly, separate disassembly is not required for the hall sensors or the voice coil. Furthermore, cost reductions are realized by the elimination of multiple conductors for various interconnects between the various devices and the main PCB of the tape drive. Additionally, elimination of several connectors allows for reductions in PCB size or utilization of PCB space for other purposes. 
         [0014]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. 
           [0016]      FIG. 1  illustrates a typical LTO tape cartridge; 
           [0017]      FIG. 2  illustrates a typical LTO tape drive housing with the cartridge of  FIG. 1  inserted; 
           [0018]      FIG. 3  is a top-down view of the cartridge inserted into the tape drive and further illustrates various internal tape drive parts; 
           [0019]      FIG. 4  is a perspective view of an actuator assembly, in accordance with an exemplary embodiment; 
           [0020]      FIG. 5A  is a perspective view of a fine actuator, in accordance with an exemplary embodiment; 
           [0021]      FIG. 5B  is cut-through perspective view of the fine actuator of  FIG. 5A ; 
           [0022]      FIG. 6  is a perspective view of a backside of a head carriage which illustrates an embodiment for precisely locating positional sensors, in accordance with an exemplary embodiment; 
           [0023]      FIG. 7A  is a perspective view of a voice coil, a voice coil holder and the head carriage which illustrates an embodiment for clamping a voice coil flex circuit to a first head flex circuit, in accordance with an exemplary embodiment; and 
           [0024]      FIG. 7B . is a perspective view of the voice coil holder and the voice coil  414 , in accordance with an exemplary embodiment; 
           [0025]      FIGS. 8-12  are various perspective views illustrating an alternative embodiment for clamping the voice coil flex circuit to the first head flex circuit, in accordance with an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, apparatuses and methods which are meant to be exemplary and illustrative, not limiting in scope. 
         [0027]      FIG. 1  illustrates a typical LTO tape cartridge  10  and  FIG. 2  illustrates a typical LTO tape drive housing  200  with the cartridge  10  of  FIG. 1  inserted. Cartridge  10  is inserted into drive  200  in a direction specified by arrow  12 . Cartridge  10  also includes grip lines  14  for easy handling. Additionally, cartridge  10  includes various lock depressions  18  (also repeated on the opposite side) that mate with a male counterpart, in drive  200 , to ensure a snug fit after cartridge  10  is inserted into drive  200 . Drive  200  includes an eject button  202  and various indicators  204 . The drive  200  may be designed to fit into a half-high 5.25 inch form factor for installation into a bay of a desktop or server box. Of course, other implementations are possible. For example, the drive  200  may be a stand-alone unit, such as a desktop drive that is external from a host computing system. 
         [0028]      FIG. 3  is a top-down view of the cartridge  10  inserted into the tape drive  200  which includes a head actuator assembly that incorporates aspects of the claimed embodiments. A full description of the various components of drive  200  is intentionally not included in order to not unnecessarily obscure the claimed embodiments. However, some of the major components include a take-up hub  300 , various tape-threading roller guides ( 302 ,  306 ), magnetic head  304  and head flex circuits ( 310 ,  312 ). Drive  200  will also typically contain one or more processors, a memory and a controller. 
         [0029]    The following sections will now describe the claimed embodiments in detail beginning with  FIG. 4 , which is a perspective view of an actuator assembly  400 , and  FIG. 5A , which is a perspective view of a fine actuator  500 , in accordance with an exemplary embodiment. Actuator assembly  400  includes a base plate assembly  402  upon which the balance of the actuator assembly components are directly or indirectly coupled to. One of those components is the fine actuator  500  that includes a magnetic head  304 , a head carriage  404  to which the magnetic head  304  is coupled to, a reference hall sensor  418  (see  FIGS. 6-8 ) mated with the head carriage  404  and a linear hall sensor  420  (see  FIGS. 6 and 9 ) which is also mated with the head carriage  404 . The fine actuator further includes a voice coil motor which includes a voice coil holder  412  coupled to the head carriage  404  and a voice coil  414  coupled to the voice coil holder (refer to  FIGS. 7 and 8  to view the voice coil holder  412  and the voice coil  414 ). Head flex circuits ( 310 ,  312 ) are used in conjunction with the actuator assembly  400  and are attached to the head carriage  404 . The head flex circuits ( 310 ,  312 ) provide electrical connections to the magnetic head  304  and one of them ( 310 ,  312 ) or both can further provide electrical connections to the voice coil  414  and positional sensors ( 418 /refer to  FIG. 6 ). Note that the head carriage  404  is for the most part blocked in the view of  FIG. 4  by the head flex circuits ( 310 ,  312 ). 
         [0030]    A head carriage assembly refers to the combination of the magnetic head  304  and the head carriage  404 . Also, some embodiments utilize the phrase “magnetic head assembly” and that refers to the head carriage  404 , magnetic head  304 , head flex circuits ( 310 ,  312 ) and positional sensors ( 418 ,  420 ). 
         [0031]      FIG. 5B  depicts a cut-through perspective view of the fine actuator  500  of  FIG. 5A . One portion of the fine actuator  500  is its moving mass and that includes the magnetic head  304 , the head carriage  404 , the voice coil holder  412 , the voice coil  414 ; the head flex circuits ( 310 ,  312 ) and the sensors ( 418  and  420 ). This collection of parts is referred to as the moving mass because it moves via the force created by the voice coil  414  under servo-control electronics. The flexures  416   a  and  416   b  suspend the entire moving mass of the fine actuator  500 . One side of the flexures ( 416   a ,  416   b ) is secured to the moving mass by the clamps  417   a  and  417   b . The clamps ( 417   a ,  417   b ) and the relevant screws (not shown) are also part of the moving mass. The other side of the flexures ( 416   a ,  416   b ) is secured to the coarse base  406 , by the clamps  437   a  and  437   b  and screws (not shown). The voice coil  414  is inside a magnetic field of the voice coil motor  440  which is attached to the coarse actuator base  406 . 
         [0032]    The actuator assembly  400  further includes a coarse actuator which is not visible in the various views of the figures. The coarse actuator, which includes a stepper motor with a gear train, translates the fine actuator  500  up or down across the full width of a tape. The coarse base  406  is guided via the precision guide-pins  408 . There are biasing springs  410  to eliminate the backlash of the gears. The precision guide-pins  408  are secured to the actuator base plate  402  at the bottom and by the top-cap  413  at the top using screws (not shown). 
         [0033]    The following sections summarize the basic operation of the positional sensors ( 418 ,  420 ) which are utilized to place the magnetic head  304  at a correct vertical position in relation to a tape track. In combination with servo signals contained on a tape, the fine actuator  500  is moved responsive to signals transduced by servo read elements, located on the magnetic head  304 , which read servo bands on a magnetic tape. The movement of the fine actuator  500 , based on the transduced servo signals, keeps the magnetic head  304  in substantial alignment with a selected track on the tape. 
         [0034]    The trigger point of the reference hall sensor magnet assembly (located on the base plate assembly  402  but not shown) provides a known location for the magnetic head  304  with respect to tape. The linear hall sensor  420  along with a reference hall sensor magnet assembly  411  (located inside a slot of the coarse base  406  /refer to  FIG. 4 ) that provides the translation information of the fine actuator  500 . 
         [0035]    Regarding the reference hall sensor  418  and the reference hall sensor magnet assembly, during a read-write process of the tape drive  200 , the magnetic head  304  traverses across a tape to seek a relevant track. There are a number of incidents when the magnetic head  304  must be parked at a given known/reference location. Such events may include booting up the tape drive  200 , tape-loading sequence, etc. In order to send the magnetic head  304  to this reference location, the reference hall-sensor magnet assembly and reference hall sensor  418  are utilized. The reference hall magnet assembly is secured to the actuator base plate  402  and the reference hall sensor  418  is secured to the head flex circuit  310 . The actuator base plate  402  is stationary to the drive  200 . Thus, when the reference hall sensor  418  arrives in the vicinity of the reference hall magnet assembly, the reference hall sensor  418  is triggered. This information is utilized to locate the magnetic head  304  with respect to the tape. 
         [0036]    In reference to the linear hall sensor  420  and the reference hall sensor magnet assembly  411 , the fine actuator  500  is utilized to keep the head on a track under a servo control. Any movements in the tape or head carriage  404  can create a misalignment between the magnetic head  304  and the track on the tape. It should be noted that the linear hall sensor  420  is utilized for motion of the fine actuator  500 , only. The linear hall sensor  420  is attached to the head flex circuit  312 . The corresponding dual pole magnet is attached to the coarse actuator base  406 . The linear hall sensor  420  will move with respect to the dual pole magnet. The dual pole magnet has two poles—north and south. When the linear hall sensor  420  is aligned to a null line of the dual pole magnet, there is no signal. When the magnetic head  304  moves up, the linear hall sensor  420  produces the signal which is proportional to the head-translation. The same is true when the magnetic head  304  moves in the negative direction. As a result, the linear hall sensor  420  provides the signal which is proportional to the head translation. This information can be used in number of ways. Some examples include 1) damping of the servo loop and 2) when tape is at the end and it reverses the direction to move from forward to reverse, there is no servo information from the tape. The linear hall sensor  420  provides the head location information during this phase. 
         [0037]    As previously mentioned, accurate placement of the positional sensors (reference hall sensor  418  and linear hall sensor  420 ) in relation to the magnetic head  304  and associated reference magnets is critical. Due to deficiencies in the prior art, misplacement of the positional sensors typically result in a significant actuator rejection rate during assembly. The claimed embodiments advantageously improve upon this situation. How this is achieved can be seen via  FIG. 6  which is a perspective view of a backside of the head carriage  404  which illustrates an embodiment for precisely locating positional sensors ( 418 ,  420 ), in accordance with an exemplary embodiment. The positional sensors ( 418 ,  420 ) are attached at respective ends of the head flex circuits ( 310 ,  312 ) and fold over the top cap  413  (refer to  FIG. 4 ). The head flex circuits ( 310 ,  312 ) each also have bottom ends ( 421 ,  423 ). As shown in  FIG. 4 , the bottom ends ( 421 ,  423 ) are limited in width. This limited width facilitates installation of the sensors ( 418 ,  420 ) in accordance head flex circuit design guidelines. 
         [0038]    The linear hall sensor  420  is electrically coupled to head flex circuit  312  (not shown) and the reference hall sensor  418  is electrically coupled to head flex circuit  310 . Head carriage  404  includes sensor location features  418   a  and  420   a  into which the positional sensors ( 418 ,  420 ) can be securely and accurately placed. Placement of the sensor location features ( 418   a ,  420   a ) on the head carriage  404  can be very accurately controlled due to advanced manufacturing processes used to produce the head carriage  404 . Some examples of advanced manufacturing processes used to fabricate the head carriage  404  include machining and die casting which is primarily used for aluminum parts. Therefore, the sensor location features ( 418   a ,  420   a ) determine the location of the positional sensors ( 418 ,  420 ) even though those positional sensors ( 418 ,  420 ) are electrically coupled/mounted on the head flex circuits ( 310 ,  312 ). As a result, the tolerances for the mounting locations of the positional sensors ( 418 ,  420 ) relative to the head flex circuits ( 310 ,  312 ) can be relatively large. Any misplacement of the positional sensors ( 418 ,  420 ) on the head flex circuits ( 310 ,  312 ) is corrected when the positional sensors ( 418 ,  420 ) are placed within their corresponding sensor location features ( 418   a ,  420   a ). 
         [0039]    In one implementation, the sensor location features ( 418   a ,  420   a ) are cut-through sections on the head carriage  404 . In another implementation, the sensor location features ( 418   a ,  420   a ) are indentations in the head carriage  404 . 
         [0040]    In yet another implementation, only one dimension of the sensor location features ( 418   a ,  420   a ) substantially corresponds to a corresponding dimension of the sensors ( 418 ,  420 ). For example, if a shape of the sensor ( 418  or  420 ) is generally rectangular or square, either the length or width could substantially correspond to a corresponding dimension of the sensor location features ( 418   a ,  420   a ). This particular implementation could be employed in a situation where a sensor ( 418  or  420 ) is required to be accurately located in a horizontal plane or a vertical plane but not both. For example, a sensor ( 418  or  420 ) could perhaps only need to be located anywhere on head carriage  404  at a specific y-axis horizontal point as defined by the axes  450  in  FIG. 6 . As a result, only a specific vertical dimension of the sensor location feature ( 418   a ,  420   a ) would need to defined, in head carriage  404 , with a midline at the required y-axis point. The horizontal dimension of the sensor location feature ( 418   a  or  420   a ) would only need to be large enough to accommodate the corresponding horizontal dimension of the sensor ( 418  or  420 ) but could be larger as the vertical x-axis location is not critical. In a similar manner, a sensor ( 418  or  420 ) could perhaps have an installation requirement to be located at a specific x-axis vertical location but have no required y-axis horizontal location requirement. As a result, a horizontal dimension of the sensor location feature ( 418   a  or  420   a ) would need to be defined on head carriage  404  with a midline at the specific x-axis vertical point. The vertical dimension of the sensor location feature ( 418   a  or  420   a ) would need to be wide enough to accommodate a corresponding vertical dimension of the sensor ( 418  or  420 ) but can be larger thus allowing a larger vertical x-axis installation window. 
         [0041]    It should also be noted that the sensor location features ( 418   a ,  420   a ) are an integral or integrally formed aspect of the head carriage  404 . 
         [0042]    Typically, the positional sensors ( 418 ,  420 ) are mated with the sensor location features ( 418   a ,  420   a ) utilizing a light press fit or a light clearance fit to ensure that the positional sensors ( 418 ,  420 ) remain fitted to location sensor features ( 418   a ,  420   a ). In one implementation, an adhesive is utilized to attach one side of the positional sensors ( 418 ,  420 ) to the head flex circuits ( 310 ,  312 ) and the other side of the positional sensors ( 418 ,  420 ) to the head carriage  404 . In another implementation, pressure sensitive tape is utilized which has an adhesive on both sides of the tape. Determining an appropriate size for the sensor location features ( 418   a ,  420   a ) is determined in relation to the size of the positional sensors ( 418 ,  420 ). Determining an optimal size for the sensor location features ( 418   a ,  420   a ) in order to ensure a proper fit for the positional sensors ( 418 ,  420 ) is well within the skill set of the average artisan and will therefore not be described so as to not unnecessarily obscure the claimed embodiments. 
         [0043]    Head carriage  404  further includes various design-dependent features that are generally independent of the claimed embodiments. Restated, their inclusion and placement may, in some implementations, effect the claimed embodiments while in other implementations have no effect at all. Some of these design-dependent features include weight-reducing cutouts  452  and locating knobs  454  which can mate with a corresponding depression (not depicted in the figures) in the voice coil holder  412 . The locating knobs  454  facilitate installation of a new head carriage assembly. For example, if during the final test, it was discovered that the head carriage assembly is defective, it will be necessary to replace it. In this situation, a new head-carriage assembly would be positioned in substantially the same position as the defective head carriage assembly due to the locating knobs  454   
         [0044]    Head carriage  404  also includes various compartments  456  which are also repeated on the other side of the head carriage/refer to  FIG. 9 . Typically, only one of the compartments  456  will be utilized even though both will be on the head carriage  404 . A compartment  456   a  (refer to  FIGS. 7A-7B ) is utilized to clamp portion of flex circuits together and this will be further described in a subsequent section. The head carriage  404  also has a tab  458  used to secure the head carriage assembly to the voice coil holder  412  via an additional screw (not shown) that goes between the head carriage  404  and the top flexure clamp  417   a.    
         [0045]    The claimed embodiments also provide for a reduced number of separate connections to the tape drive PCB from various drive components. For example, the positional sensors ( 418 ,  420 ) are mounted on the head flex circuits ( 310 ,  312 ). As a result, separate PCB connectors are not required for the positional sensors ( 418 ,  420 ). In a similar manner, head flex circuit  310  can also be utilized to provide a connection between the voice coil motor and the PCB. More specifically, though, the claimed embodiments provide for the connection between the voice coil  414  and the head flex circuit  310  without the use of soldering and is described via  FIGS. 7A-7B . 
         [0046]      FIG. 7A  is a perspective view of the voice coil  414 , a voice coil holder  412  and the head carriage  404 .  FIG. 7B . is a perspective view of the voice coil holder  421 . Additionally,  FIGS. 7A and 7B  illustrate an embodiment for clamping a voice coil flex circuit  422  to a portion of the head flex circuit  310   a , in accordance with an exemplary embodiment. Referring to  FIG. 7B , a thin rectangular part  470 , made from a compliant material, is located in the compartment  456   a  and the thin rectangular part  470  is attached to a wall of the compartment  456   a  using pressure sensitive tape. An example of a compliant material to use for the thin rectangular part  470  is Buna-N rubber, or a similar material, with a thickness of about 0.50 mm, in one implementation, and a shore hardness of about 30 shore-A, in one implementation. The purpose of the thin rectangular part  470  is to ensure that there will be a clamping force between the relevant pads of the voice coil flex circuit  422  and the head flex circuit portion  310   a . Due to mechanical tolerance conditions of the voice coil flex circuit  422  and the head flex circuit portion  310   a , sufficient clamping force may not be ensured without the presence of the thin rectangular part  470 . It should be noted that while the thin rectangular part  470  is rectangular, the claimed embodiments are not meant to be limited in such a fashion as various other shapes can be utilized. The thin rectangular part  470  is rectangular since the compartment  456   a  is also rectangular. It should also be noted that  FIG. 7B  intentionally does not include the voice coil flex circuit  422  in order to be able to show the thin rectangular part  470 . 
         [0047]    The voice coil  414  includes two wires (not shown) which are soldered to the voice coil flex circuit  422  at their respective ends. The voice coil flex circuit  422  is attached to the voice coil  414  using an adhesive between the voice coil  414  and the voice coil flex circuit  422 . The voice coil flex circuit  422  is designed to have two lines that form an electrical continuity between the voice coil wires and the two pads at its other end where the voice coil flex circuit  422  is clamped to the head flex circuit portion  310   a . The end of the voice coil flex circuit that is clamped to the head flex circuit portion  310   a  has two exposed pads—a positive pad and a negative pad. The voice coil flex circuit  422  is routed from the voice coil  414 , as shown in  FIG. 7A , and terminates at the compartment  456 . The end of the voice coil flex circuit  422 , where the two pads rests on the thin rectangular part  456 , is secured to the thin rectangular part  456  using pressure sensitive tape. The exposed pads are facing out meaning they can be seen when the head carriage  404  is not assembled. In a similar fashion, head flex circuit portion  310   a  wraps around to the backside of head carriage  404  and has two corresponding positive and negative pads. Electrical connectivity between the pads is accomplished when the voice coil motor  412  is securely clamped with the head carriage  404 . The positive and the negative pads are substantially mated because both of the flex circuits ( 310   a ,  422 ) along with the thin rectangular part  470  are placed in the compartment  456 . The force necessary to mate these pads comes by a screw, which is placed on the head carriage  404  and is threaded into the threaded-hole  426   a  of the voice coil holder  412 . This particular screw is also used to attach the head carriage assembly to the voice coil holder  412 . Furthermore, there are additional screws used to attach the head carriage to the voice coil holder are fastened at the threaded holes  424   a ,  428   a  and  430   a.    
         [0048]    Since the embodiment of  FIGS. 7A-7B  does not utilize soldering to connect the voice coil flex circuit  422  to head flex circuit portion  310   a , the various disadvantages associated with soldering that were described in the background section are eliminated for this particular connection. Additionally, the embodiment of  FIGS. 7A-7B  further allows for the head carriage  404  to be directly removed from the actuator assembly  400  as there are only screws holding the head carriage  404  to the voice coil holder  412  and no soldered connections to undo. This aspect is particularly advantageous as the head carriage can be easily/directly removed from the actuator assembly in case the magnetic head needs to be repaired or replaced. 
         [0049]    The claimed embodiments also envision an alternate clamping embodiment to connect a voice coil flex circuit to a head flex circuit and this embodiment is depicted via  FIGS. 8-12 . Instead of clamping a voice coil flex circuit with a head flex circuit between the head carriage  404  and the voice coil holder  412 , the embodiment of  FIGS. 8-12  instead clamps a voice coil flex circuit  432  and a portion of the head flex circuit  310   b  between the voice coil holder  412  and the top flexure clamp  417   a . In another implementation, a portion of head flex circuit  312  is utilized to be clamped with voice coil holder  412 . It should be noted that only  FIG. 12  shows top flexure clamp  417   a.    
         [0050]    Similar to the previous embodiment, voice coil flex circuit  432  has positive and negative pads ( 434   a ,  436   a /see  FIG. 11 ) that match up with corresponding positive and negative pads ( 434   b ,  436   b /see  FIG. 10 ). The clamping and resultant electrical connection is accomplished by inserting screws into the top flexure clamp at holes  438  and  440  ( FIG. 12 ) which in turn go through holes  441  and  442  ( FIG. 11 ) of voice coil flex circuit  432 , hole  444  ( FIG. 10 ) of head flex circuit portion  310   b  and holes  446  and  448  ( FIG. 9 ) of the voice coil holder  412 . 
         [0051]    This embodiment also eliminates the need to solder the voice coil flex circuit  432  to the head flex circuit portion  310   b . However, in order to remove the head carriage  404  from the actuator assembly  400 , the top flexure clamp  417   a  will need to be removed as well as the screws holding the voice coil holder  412  to the head carriage  404 . 
         [0052]    Advantageously, the claimed embodiments provide for numerous advantages over the prior art. These advantages include precise placement of positional sensors, integration of connections without soldering and improved removal processes for detaching a magnetic head assembly from an actuator assembly. 
         [0053]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.