Abstract: Disclosed herein are embodiments of motion limiting cover features that improve coil/VCM coupled resonance. The features are flexible in that their position and configuration can be customized to specifically target a certain type of undesirable motion, such as undesirable twisting (i.e., torsion) and/or bending.

Abstract: In a data handling system having a radially-dependent track incongruity between data surfaces, at least some tracks are logically mapped so that tracks on different data surfaces correspond with one another. The correspondence is defined by the mapping so as to shorten an average headswitch seek. For example, a logical track mapping of first and second non-coaxial track sets can be defined so as to optimize a headswitch seek within each of many intermediate logical cylinders identified in the mapping.

Abstract: Method and apparatus for identifying a resonance by changing a spindle speed, which has the effect of changing a corresponding sampling rate and Nyquist frequency. The invention discriminates (1) between plausible frequencies of true resonance and/or (2) aliased resonance from non-aliased resonances. This is accomplished by monitoring whether and/or how a resonance shifts during this speed change. Methods of the present invention monitor resonances by deriving a resonance indicator such as an apparent frequency (below the Nyquist frequency), a gain or error magnitude (compared to a derived threshold at a calculated frequency of interest), or similar criteria tested by values conventionally illustrated on a Bode plot. The present invention further includes steps or structural features for configuring a controller to attenuate or similarly limit an unwanted frequency component of an actuator control signal. In this way, resonances in the actuator can be reduced, and servo speed and accuracy thereby enhanced.

Abstract: An apparatus and method for minimizing damage to a disc drive assembly subjected to non-operational shock. The disc drive has rotatable discs upon which data can be written and read by read/write heads supported by and controllable by an actuator assembly having actuator arms moveable over the complete data containing surfaces of the discs. A disc snubber is supported in apertures in the actuator arms, the disc snubber having bumper arms radially extending to nest the outer perimeters of the discs when the disc drive assembly is in its non-operational mode. The disc snubber is in clearing relationship to the discs in the operational mode. The disc snubber is disposed to dampen disc deflection caused by non-operational shock, thereby avoiding deleterious actuator arm/disc contact.

Abstract: A disc drive having reduced mechanical vibration is disclosed. An annular viscoelastic damper is sandwiched beneath the head disc assembly cover against the bearing assembly of the actuator to dampen mechanical vibrations transmitted by the cover to the actuator assembly. The damper is an annular disc made of a composite of a layer of viscoelastic polymer and a backing stiffening layer.

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 shaft supported by a baseplate, the shaft supporting a plurality of vanes to rotate the shaft in response to airflow generated by disc rotation. A locking member is operably engaged with the shaft and moveable thereby to a latched position and to an unlatched position, the actuator being secured by the locking member in the latched position and the actuator being released to move freely in the unlatched position. The locking member is caused to be positioned in the unlatched position when airflow rotates the vanes and shaft, and a biasing member reverse rotates the shaft when the airflow ceases, thus returning the locking member to the latched position when the disc drive becomes non-operational.

Abstract: Apparatus and method for enhancing the convective cooling of a voice coil motor (VCM) of a disc drive. A portion of an air flow established by the rotation of a disc of the disc drive is diverted from the disc and is directed through a channel to the VCM. In one embodiment, an air foil is provided to support first and second magnetic paths of the VCM, the air foil having a shroud surface adjacent portions of the circumference of the disc and a diverter surface angularly extending from the shroud surface, the diverter surface diverting the air to the VCM. Alternatively, a base deck of the disc drive is provided with a shroud circumferentially adjacent portions of the disc and the channel extends through the shroud to direct the air from the disc to the VCM.

Abstract: Apparatus and method for measuring the maximum static friction force and the kinetic friction force between the heads of a disc drive and discs adjacent the heads. The disc drive is rotated by a computer controlled spin-up motor which provides constant angular acceleration of the disc drive. Voltages at the ends of the windings of a spindle motor of the disc drive are sampled to detect the angular acceleration at which disc rotation relative to the heads begins, from which the static friction force and the kinetic friction force are determined. The angular acceleration of the disc drive is monitored through the sampling of velocity commands used to control the angular acceleration of the disc drive, or through the use of an accelerometer mounted with respect to the disc drive.