Abstract: An apparatus and method are disclosed for recovering from a header error condition in a disc drive of the type having a rotatable disc having a plurality of concentric tracks with data fields for the storage and retrieval of data and header fields providing logical address information for the data fields. The header fields include read and write header fields which are used during read and write operations, respectively, to align read and write elements of the head with the data fields. When the disc drive unsuccessfully decodes the logical address information from a selected header field associated with a selected data block, an alternate header error recovery routine is performed wherein attempts are made to decode the logical address information from the alternate header field associated with the selected data block. Radial offsets can further be applied to the head to enhance the decoding of the logical address information from the alternate header field.

Abstract: An apparatus and method are disclosed for optimizing write performance of a disc drive through the use of write thresholds that are adaptive by head and by disc location. The disc drive has a head which is controllably positionable adjacent each of a plurality of nominally concentric tracks defined on a rotatable disc, which selectively magnetizes the tracks to write data to the tracks. A servo circuit of the disc drive controls the position of the head and prevents the head from writing data to the tracks until the head is positioned within write thresholds which are separately defined for each of the tracks. The write thresholds for each of the tracks are stored in memory and accessed by a digital signal processor of the servo circuit at the commencement of each write operation by the disc drive.

Abstract: A bobbin for providing a heat sink for an actuator coil of a voice coil motor, the actuator coil having a plurality of windings arranged about a central aperture, the bobbin having a body member supported within the central aperture of the actuator coil. The body member has a plurality of fins which increase the surface area within the actuator coil to provide enhanced heat dissipation. The bobbin is formed from a thermally conductive, dielectric material to facilitate the dissipation of heat generated in response to the application of current to the actuator coil to reduce the operational temperature thereof while preventing detrimental eddy currents, thereby allowing an increased current flow to effectuate a decrease in seek time.

Abstract: An apparatus and method are disclosed for generating a low ripple negative voltage suitable for use in a disc drive. A negative voltage supply comprises a pulse generator circuit which generates first and second driver signals in relation to a load of the negative voltage supply. The first driver signal comprises a series of periodically occurring first pulses and the second driver signal comprises a series of periodically occurring second pulses. The first and second pulses are mutually exclusive in time so that at least a minimum delay of selected, nonzero length is provided between transitions of subsequently occurring first and second pulses. The negative voltage supply further comprises a regulator circuit, operably coupled to the pulse generator circuit, which generates the negative voltage in response to the first and second driver signals utilizing a pair of storage capacitors which alternately accumulate and transfer charge to an output capacitor in response to the first and second driver signals.

Abstract: Apparatus and method for providing static and dynamic balance in a disc drive having three recording discs. A spindle motor hub includes an outer surface which circumferentially extends about a central axis at an outer radius less than a disc inner radius. A groove is formed in the hub to provide a groove inner surface having a groove radius less than the hub outer radius. The groove radius is selected to be twice the hub outer radius minus the disc inner radius. First and third discs are loaded onto the hub and shifted to bring respective disc inner surfaces into abutment with the hub outer surface at a first angular location. The second, intermediate disc is loaded onto the hub and shifted to bring the disc inner surface into abutment with the groove inner surface at a second angular location opposite the first angular location.

Abstract: A method is disclosed for optimizing write performance of a disc drive through the selection of optimum write thresholds. The disc drive has a controllably positionable head adjacent tracks defined on a recording surface of a rotatable disc. A narrow head detection test is first applied whereby data are written to a selected track while maintaining the head at a first off-track center distance. The data are read while maintaining the head at a position nominally over the center of the selected track and measuring resulting read error performance. These steps are then repeated using a second off-track center distance.

Abstract: Apparatus and method for reducing the generation of acoustic noise in a disc drive. A seek is carried out to move a head from an initial track to a destination track on a corresponding disc surface using a servo circuit which outputs a series of current command values indicative of successive magnitudes of current to be applied to an actuator motor. A velocity profile provides a sequence of demand velocities indicative of the desired velocity as the head is decelerated to the destination track. During the seek, open loop current is applied to the actuator motor to accelerate the head away from the initial track, the current command values defining a rising portion wherein the current is successively increased to a first level and a subsequent falling portion wherein the current is successively decreased to a second level, the rising and falling portions each preferably characterized as a one quarter sine wave at a selected frequency.

Abstract: A damper for dampening resonance created by a voice coil motor of a disc drive and transmitted to a supporting enclosure, the resonance capable of creating noise signals to the disc drive servo control system. The damper has a dampening member and a liner, the liner being a magnetically permeable member that is magnetically attracted to the voice coil motor and thereby pressingly engaging a magnet housing of the voice coil motor. In a preferred embodiment the dampening member is an acrylic polymer. In an alternative embodiment the dampening member is a fluoroelastomer. The magnet housing has characteristic features that increase the magnetic flux to the liner.

Abstract: Apparatus for protecting a disc drive from damage due to non-operational mechanical shocks, the disc drive comprising a rotatable disc having an inner radius and an outer radius and a controllably rotatable actuator adjacent the disc. A snubber is provided adjacent the disc, the snubber having a body portion rigidly affixed with respect to the disc and snubber arms connected to the body portion. The snubber arms extend from the body portion towards the disc and above and below the elevation of the disc, with each snubber arm having a distal end located at a position adjacent the disc between the inner and the outer radii of the disc and towards the outer radius of the disc. The height of each snubber arm limits deflection of the disc at the outer radius of the disc as a result of mechanical shock forced supplied to the disc drive assembly.

Abstract: The present invention provides a double grooved spacer for reducing coning of discs. A double grooved spacer includes a body portion with a plurality of spring flanges radially extending therefrom to form an inner radial groove and an outer radial groove. The body portion in conjunction with the plurality of spring flanges form a generally I-shaped cross-section. The double grooved spacer further includes circumferentially extending contact nodes disposed on the spring flanges so that the clamping force is localized at selected positions on the discs and the double grooved spacers to provide uniform distribution of the clamping force within the disc stack.

Abstract: A flex circuit support and apparatus (148) for a disc drive (100) comprising a flex circuit (150) with a conductor portion (154), a rigid dielectric support bracket (156), and a compressible, deformable resilient dielectric gasket seal (174), and extends through a connector aperture (162) of a basedeck (104). The support bracket (156) has a base portion (158) and a connector portion (160) vertically extending bi-directionally from the base portion (158). The gasket seal (174) is secured between the basedeck 104 and the support bracket (156). The connector portion 160 supports the conductor portion (154) of the flex circuit (150) and extends through the connector aperture (162). The support bracket (156) and the attached flex circuit (150) is secured to the basedeck (104) in a conventional manner through the use of fasteners (161).

Abstract: Apparatus and method for improved disc drive data storage capacity and seek performance. The disc drive includes a rotatable disc with a recording surface on which a plurality of tracks are defined and an actuator which supports a head adjacent the tracks. A servo circuit uses a velocity profile to position the head adjacent a destination track, with the servo circuit adaptively selecting the velocity profile in relation to the physical location of the destination track. The servo circuit preferably uses a reduced maximum velocity and a decreased deceleration rate when the deceleration track is adjacent an innermost or outermost diameter of the disc, thereby reducing the risk of damage as a result of contact between the actuator and a limit stop used to limit radial excursion of the head.

Abstract: An apparatus and method are disclosed for minimizing settling time in a disc drive servo system. The disc drive includes a head adjacent a rotatable disc on which a plurality of tracks are defined and a motor which controllably positions the head in response to current applied to the motor. A servo circuit is provided to settle the head onto a destination track at the conclusion of a seek operation by determining velocity of the head at a selected distance from the destination track, comparing the velocity to a desired velocity of the head at the selected distance from the destination track, adding a settling gain to a current command signal to generate a modified current command signal in relation to a difference between the velocity and the desired velocity, and using the modified current command signal to settle the head onto the destination track.

Abstract: An improved pivot mechanism for a disc drive actuator assembly, the actuator assembly having an E-block which supports an array of read/write heads in reading and writing data relationship to a plurality of data discs, the actuator assembly having a bearing cartridge that rotatably supports the E-block and is receivingly disposed within a bore of the E-block and fixed therein by a tolerance ring interposed in the bore between the bearing cartridge and the E-block. The bearing cartridge has a hollow sleeve that supports the tolerance ring on an outer diameter thereof, and furthermore supports a damping member on the inner diameter thereof. The damping member is attached to the sleeve by a selected damping material.

Abstract: An actuator latch for latching an actuator of a disc drive having a rotating disc that induces airflow when the disc drive is operational, the actuator latch having a horizontally disposed shaft supported by a pair of bearing clips for sliding and rotational movement of the shaft, the shaft supporting a plurality of propeller blades to rotate the shaft in response to airflow generated by rotation of the disc. A torsion return spring is attached to the shaft at a proximal end and to the disc drive at a proximal end, so that rotation of the shaft winds up the torsion return spring and urges the shaft longitudinally in a direction toward the torsion spring distal end. In the absence of airflow the torsion spring unwinds and urges the shaft in a direction away from the distal end thereof.

Abstract: Apparatus and method for increasing sweep angle of a rotary actuator in a disc drive. The actuator supports a head adjacent a surface of a disc and an actuator coil adjacent a permanent magnet assembly. The actuator coil has first and second active lengths which magnetically interact with adjacent first and second magnet portions of the permanent magnet assembly, with the permanent magnet assembly generating a magnetic flux reversal at a transition zone between the first and second magnet portions. The head is moved by applying current in a first direction to move the actuator coil in a selected coil direction, thereby causing a selected one of the first and second active lengths to cross the transition zone. The polarity of the current is then reversed so that the current is applied in a second direction opposite the first direction, which causes the actuator coil to continue to move in the selected coil direction.

Abstract: A convertible roll forming apparatus for forming flanges on a strip of material in which a roller assembly is supported on a support stand and disposed to move the strip material in a material feed direction. A pivotal support assembly supports a knuckle member for pressing against an edge portion of the strip material, the knuckle member cooperating with the support assemblies to progressively form the edge portion into a flange. The support assembly can be selectively disposed to form the edge portion in a first direction or in an opposing second direction. The strip material can be passed through serial passes of support assemblies and knuckle members to progressively form the flange. The roller assembly is supported for lateral expansion to accommodate various widths of strip material as required, and a lip forming section is provided to form a lip on the outer edge of the formed flange. Flange straightener assemblies are also provided to control the overbend.

Abstract: An apparatus and method are disclosed for minimizing damage to a disc drive during head switching operations. The disc drive comprises a plurality of magnetic recording surfaces to and from which data are transferred using read/write heads, each head utilizing the application of a bias current during operation. To switch from a presently selected head to a target head, the disc drive determines a first value indicative of the magnitude of a bias current for the presently selected head and a target bias current to be applied to the target head. When the second value is greater than the first value, the disc drive switches from the presently selected head to the target head and then applies the target bias current; conversely, when the first value is greater than the second value, the target bias current is applied to the presently selected head and then the disc drive switches from the presently selected head to the target head.

Abstract: A low inductance electrical compression connector for a disc drive interconnecting conductors of a flex circuit to conductive traces on a PCB, the electrical compression connector having a dielectric housing with a plurality of spaced apart insulator portions and conductive compression contacts disposed between the insulator portions. The insulator portions, the dielectric housing and the conductive compression contacts form open ended deflection cavities disposable above the PCB. First ends of the conductive compression contacts and solderable to conductive traces on the PCB, while second ends of the conductive compression contacts are pre-load spring contacts disposable above respective deflection cavities. Inserting the conductors of the flex circuit beneath the pre-load spring contacts into the deflection cavities causes the pre-load spring contacts to engage the conductors of the flex circuit to secure the flex circuit against the printed circuit while providing electrical contact.

Abstract: A latch for a disc drive, wherein the disc drive has an actuator that is pivotally supported for moving an array of read/write heads radially across a data storage disc between a parked location and a data storage location, the parked location providing a landing surface for the read/write heads when the disc drive is non-operational, the latch limiting the actuator from pivoting so that the read/write heads remain in the parked location while the disc drive is non-operational. The latch has a base member enabling attachment to the disc drive, the base supporting an inner stop and an outer stop which limit the actuator rotation, the base further supporting a cantilevered latch arm which biases a latch finger to a position whereat the latch finger and the inner stop form a latching groove and the latch finger and the outer stop form an unlatching groove, the actuator being confined by the latching groove in the latched mode and being confined by the unlatching groove in the unlatched mode.