Abstract:
A printed circuit cable assembly for top down installation in a disc drive or the like in which a printed circuit cable supporting electrical conductor paths has a body portion, a flex portion and an insertion tab connecting the body portion and flex portion. A PCC support member having a support ramp extending into a slotted gap supports the printed circuit cable with the insertion tab extending into the slotted gap so that the flex portion is extended for attachment to a moveable article, such as the head stack assembly of a disc drive. Preferably, the PCC support member has an indexing bore, and the PCC support member with the supported printed circuit cable is mounted to a support member having an indexing post, the PCC support member positioned so that indexing bore is positioned over the indexing post.

Description:
RELATED APPLICATIONS 
       [0001]    The present application makes a claim of domestic priority to U.S. Provisional Patent Application No. 60/958,547 filed Jul. 6, 2007, which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Data storage devices store and retrieve large amounts of computerized data in a fast and efficient manner. Such devices may include one or more data storage discs that are rotated by a spindle motor at a constant high speed. Data transfers with tracks on the discs are carried out using a rotary actuator assembly (also referred to as a head stack assembly, or HSA). The HSA supports a corresponding number of data transducing heads that are controllably moved across the disc surfaces by an actuator motor (also referred to as a voice coil motor, or VCM). 
         [0003]    The spindle motor and the HSA are typically mounted to a base deck that cooperates with a top cover to provide a protected interior environment for the discs and heads. A printed circuit cable (PCC) provides the requisite electrical communication paths between the HSA and a disc drive printed circuit board (PCB) mounted to the exterior of the base deck. The disc drive PCB supports communication and control electronics for operation and control of the disc drive. 
         [0004]    The printed circuit cable (PCC) includes a flex cable that has a flexible, laminated member that electrically isolates and supports a number of embedded electrical conduction paths (conductors) along the length of the laminated member. One end of the flex cable is supported by a flex cable support (also referred to as a flex cable clamp) that is mounted on the base deck; the distal end of the flex cable is attached to the HSA. Typically, a bulkhead connector extends through the base deck to facilitate electrical connection from the flex cable support to the disc drive PCB. 
         [0005]    The intermediary portion of the flex cable between the flex cable support and the HSA is a dynamic slack loop that provides strain relief while the HSA moves the heads across the full radius of the disc surfaces. In practice, the flex cable loop acts as a spring that exerts undesired bias force on the HSA as the heads are moved to different radial positions with respect to the disc surfaces. This bias force tends to nominally urge the heads away from the desired position over a selected track, so this bias force must be within a range that is compensated by servo control circuitry of the drive to assure that the disc drive operates predictably. 
         [0006]    A disc drive design must provide printed circuit cable (PCC) configurations with controllable and repeatable flex cable dynamic loop characteristics over the desired range of HSA motion. Furthermore, there is a continuing trend to improve not only disc drive operational characteristics, but also to improve disc drive manufacturing processes. Top down assembly (unidirectional positioning and installation of components in the disc drive) has become the ultimate goal in creating low cost disc drives. It is to such improvements that the claimed invention is directed. 
       SUMMARY 
       [0007]    In accordance with preferred embodiments, a printed circuit cable assembly for top down installation in a disc drive or the like in which a printed circuit cable supporting electrical conductor paths has a body portion, a flex portion and an insertion tab connecting the body portion and flex portion. A PCC support member having a support ramp and a slotted gap supports the printed circuit cable with the insertion tab extending into the slotted gap so that the flex portion is extended for attachment to a moveable article, such as but not limited to the head stack assembly of a disc drive. 
         [0008]    Preferably, the PCC support member has an indexing bore and a support member, such as the base deck of a disc drive, has an indexing post. The PCC support member with the supported printed circuit cable is mounted to the support member such that the indexing bore is positioned over the indexing post. 
         [0009]    These and various other features and advantages which characterize the claimed invention will become apparent upon reading the following detailed description and upon reviewing the associated drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a plan view of a disc drive constructed in accordance with preferred embodiments of the present invention, the cover member being partially cutaway. 
           [0011]      FIG. 2  is a top plan view of a flex cable support of the disc drive of  FIG. 1 . 
           [0012]      FIG. 3  is a side elevational view of the flex cable support of  FIG. 2 .  FIG. 3A  is an enlarged view of a portion of the flex cable support of  FIG. 2 . 
           [0013]      FIG. 4  is a top plan view of the flex cable of the disc drive of  FIG. 1 . 
           [0014]      FIG. 5  is a flex cable connector that attaches the flex cable to the head stack assembly. 
           [0015]      FIG. 6  is a top corner perspective view of the flex cable support of  FIG. 2  with the flex cable supported thereon. 
           [0016]      FIG. 7  is a bottom corner perspective view to the flex cable support of  FIG. 2  with the bulkhead connector attached thereto. 
           [0017]      FIG. 8  is a top plan view of the flex cable support showing the area of adhesive application. 
           [0018]      FIG. 9  shows plan views of the stiffener members for the printed circuit cable. 
           [0019]      FIG. 10  is a diagram of the steps for the top down installation of the PCC cable assembly. 
       
    
    
     DESCRIPTION 
       [0020]    A detailed description of the various presently preferred embodiments of the present invention will commence with reference to  FIG. 1 . Shown therein is a data storage device  100  that includes a head-disc assembly (HDA)  102  and a printed circuit board (PCB). Although not viewable in  FIG. 1 , it will be understood that the PCB serves to control operation of the HDA  102 . 
         [0021]    A top cover  104 , partially cutaway in  FIG. 1 , mates with a base deck  106  to provide an environmentally controlled environment for the HDA  102 . A spindle motor  108  rotates one or more magnetic recording discs  110  at a constant, high speed. A rotary actuator assembly  112 , or head stack assembly (HSA), has a number of actuator arms  114  that support data transducing heads (not shown) in near proximity to the surfaces of the discs  110 . In  FIG. 1 , the HDA  102  is depicted with the actuator arms parked away from the discs  110  on a parking ramp  116 . 
         [0022]    The actuator arms  114  move the data transducing heads across the surfaces of the discs  110  through application of current to the coil of a voice coil motor (VCM)  118 . Flex on suspension (FOS) conductors  120  are routed from the heads  112  along the actuator arms  114  to accommodate data write and read signals to and from the data transducing heads. 
         [0023]    A printed circuit cable assembly  122 , also referred to herein as the PCC assembly  122 , facilitates electrical communication between the HSA  102  and the printed circuit board (PCB) on the underside of the base deck  106 . The PCB will be understood to be of a conventional configuration to support the requisite communication and control electronics for the disc drive  100 . 
         [0024]    The PCC assembly  122  includes a flexible, ribbon-like laminated flex PCC portion  124  that electrically isolates and supports a number of embedded electrical conductor paths along its length. A proximal end of the flex PCC portion  124  is attached to a PCC clamp  126  that is affixed to the HDA  112  for electrical communication therewith. 
         [0025]    The distal portion of the printed circuit cable (PCC)  122  is supported on and attached to a printed circuit cable support member  128 , or PCC support member, that is also shown in  FIGS. 2-5 . A bulkhead connector  130  (see  FIG. 3 ) extends under the PCC support member  128  to communicate through the base deck  106  and facilitate electrical connection with the underlying disc drive PCB in a conventional manner. 
         [0026]    The flex PCC portion  124  has a dynamic printed circuit loop  132  (also referred to as the PCC loop) that extends between the PCC clamp  126  (affixed to the HSA  112 ) and the portion of the PCC assembly  122  that is mounted on the PCC support  128 . The PCC loop  132  is a slack loop that allows the HSA  110  to rotate the actuator arms  114  to position the data transducing heads along their full radial path over the discs  110 . 
         [0027]    Turning to  FIG. 2 , the PCC support  128  has a generally planar shaped body portion  134  with a protrusion member  136  at one end and a hook member  138  along one edge. The protrusion member  136  has an indexing bore  140 , and the hook member  138  forms an indexing cavity  142 . Returning to  FIG. 1 , it will be noted that a pair of cylindrically shaped guide posts  144 A and  144 B are mounted to the base deck  106  by bolts extending through central bores in the guide posts  144 A,  144 B that attach to threaded bores in the base plate  106 . 
         [0028]    The outer diameter of the guide post  144 A is determined to be received in the indexing bore  140  of the protrusion member  136 ; and the outer diameter of the guide post  144 B is determined to be received in the indexing cavity  142  of the hook member  138 . The PCC support member  128  is mounted to the base deck  106  by positioning the PCC support member so that the indexing bore  140  of the protrusion member  136  and the indexing cavity  142  of the hook member  138  engage and receive the guide posts  144 A,  144 B, respectively. 
         [0029]    The PCC support  128  has a gap  146  between the end of the body portion  134  and the protrusion member  136 , and a ramp  148  extends downwardly from the body portion  134  into this gap. As shown in  FIG. 3 , the ramp  148  extends to partially fill the gap  146 , leaving the bottom of the gap  146  open, as may best be seen in the enlarged partial view of  FIG. 3A . A slide plate slot  149  extends along the protrusion member  136  and to communicate from the gap  146  to the back of the PCC support member  128 . 
         [0030]    Returning to  FIG. 2 , extending upward from the body portion  134  are a gripping member  150  and a pair of indexing posts  152 . The gripping member  150  serves as a handle for guiding and positioning the PCC support  128  onto the base plate  106 , and the indexing posts  152  serve to accept and retain the flex PCC portion  124  on the body  134 . 
         [0031]    The PCC assembly  122 , as shown in  FIG. 4 , is a flat, multi-layered member that is sufficiently flexible for wrap around assembly to the PCC support member  128 ; the construction of the PCC assembly  122  is generally conventional, having a cover layer, a layer of adhesive, a copper trace layer (the electrical conductors), another layer of adhesive, and a base layer. The copper trace layer forms a portion of the electronic circuitry of the disc drive  100 , the PCC cable  122  facilitating electrical communication between the PCB beneath the base deck  106  and the HSA  102 . A description of the circuitry of the PCC assembly  122  is not necessary for the present disclosure, other than to note that the PCC assembly  122 , as well as the PCB support the requisite communication and control electronics for the disc drive  100 . 
         [0032]    The PCC assembly  122  has a body portion  154  from which the flex PCC portion  124  extends. The body portion  154  has a pair of indexing holes  156  that are spatially positioned to be engaged over the indexing posts  152  on the PCC support member  128 . As shown, the body portion  154  has a number of other hole connectors and tab connectors that conventionally establish the required electrical communication. 
         [0033]    The proximal end of the flex PCC portion  124  is attached to the HSA  112  by means of the PCC clamp  126 , which is also shown in  FIG. 5 . The PCC clamp  26  has a base portion  158  that is adhered to the PCC portion  124  and an angled leg portion  160 . The base portion  158  has a number of connector tabs  162  to which electrical conductors of the flex PCC portion  124  are electrically secured, and the connector tabs  162  are electrically connected with solder land areas on the leg portion  160  that are soldered to appropriately disposed electrical connectors on the HSA  112 . 
         [0034]    For convenience of reference, the PCC body  154  has a top body portion  154 A, a bottom body portion  154 B and a hinge body portion  154 C extending between the top and bottom body portions  154 A,  154 B. Further, the PCC body  154  has an insertion tab  154 D that extends between the top bottom portion  154 A and the flex PCC portion  124 . As shown, the flex PCC portion  124  extends angularly from the insertion tab  154 D, preferably at about a ninety degree angle. The flex PCC portion  124  is bendable relative to the insertion tab  154 D along a bend line  154 E. 
         [0035]      FIGS. 6 and 7  show the printed circuit cable, or PCC,  122  assembled to the PCC support  128 , along with several typical electrical components  155 . The body portion  154  is folded at the hinge portion  154 C and the top body portion  154 A positioned on the top surface of the PCC support member  128  with the indexing holes  156  positioned over the indexing posts  152 . The bottom body portion  154 B is positioned on the bottom surface of the PCC support  128  with the connector  130  mounted thereon.  FIG. 8  shows the placement of PSA (pressure sensitive adhesive) tape on area  164 , and a similar area for the placement of PSA tape is provided on the opposing side of the PCC support member  128 . 
         [0036]      FIG. 9  shows a stiffener plate  166  and a stiffener plate  168  that are shaped to be adhered to the base layer of the PCC assembly  122  on the top and bottom body portions  154 A,  154 B, respectively, with an adhesive. Also shown is a stiffener plate  170  that is shaped to be adhered via adhesive to the base layer of the PCC assembly  122  at the intersection of the flex PCC portion  124  and the insertion tab  154 D. It will be noted that the stiffener plate  170  has a hook  172  that extends from the distal end of the flex PCC portion  122  at the intersection thereof with the insertion tab  154 D. 
         [0037]    The stiffener plate  166 , the stiffener plate  168  and the stiffener plate  170 , together with the PCC clamp  126 , are depicted in  FIG. 9  relative to the underlying portions of the PCC assembly  122  (in dashed line outline) when adhered to the base layer thereof, and showing the location of these stiffeners. 
         [0038]      FIG. 10  shows a flow chart for a routine  200  to show a preferred manner in which the printed circuit cable  122  is assembled. Initially, at step  202 , various components are preferably surface mounted to the PCC assembly  122 , including the connector  130 , the electrical components  155 , the stiffener plates  166 ,  168 ,  170  and the PCC clamp  126 . At step  204 , double sided PSA tape is preferably applied onto the area  164  on both sides of the PCC support member  128 . With the PSA tape in place, the completed PCC assembly  122  (with mounted components) is wrapped around the PCC support member  128 , as shown by step  206 . 
         [0039]    The PCC assembly  122  is dressed during step  208  so that the insertion tab  154 D follows the ramp  148  of the PCC support member  128 . At step  210 , the hook  172  is inserted into the slide plate slot  149  in the PCC support member  128 . Step  212  sets forth soldering the proximal end of the flex PCC portion  124  to the head stack assembly (HSA)  112  to the PCC clamp  126 . 
         [0040]    At this point, the HSA  112  will now be assembled to the base deck  106 , but it will be understood that the HSA  112  can be installed prior to the assembly  200  of the PCC assembly  122 . The final step  214  is the placement of the PCC support member  128 , with the PCC assembly  122  and components mounted thereon, on the base plate  106  with the indexing bore  140  over the guide post  144 A and the indexing cavity  142  engaging the guide post  144 B. 
         [0041]    While the various embodiments presented herein are generally provided in the context of a data storage device, it will be appreciated that this is merely for purposes of illustration and is not limiting. Rather, the exemplary printed circuit assembly as disclosed herein can be readily used in any number of other environments as desired. 
         [0042]    It will be clear that the various embodiments presented herein are well adapted to carry out the objects and attain the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes may be made that will readily suggest themselves to those skilled in the art and that are encompassed in the spirit of the invention disclosed and as defined in the appended claims.