Abstract: A coiled tubing injector for inserting and withdrawing a continuous length of tubing from a well, the coiled tubing injector having a tubing insertion and withdrawal assembly with a tubing conveyor assembly moving the tubing upward for withdrawal from the well and downward for insertion into the well. The tubing conveyor assembly has a fixed conveyor and an opposing floating conveyor each with a plurality of gripper blocks that engage the tubing. Each gripper block has a groove having a radius of curvature substantially that of the tubing to provide a close mating relationship of the gripper blocks and the tubing. The floating conveyor is moveable away from the fixed conveyor to create a gap therebetween, and the frame is provided an opening aligned with the gap between the fixed and floating conveyors so that a medial portion of the tubing can pass through the opening into the gap.

Abstract: Apparatus and method for detecting servo defects in a disc drive, the servo defects providing false indications of the position of a disc drive head with respect to a selected track. During use of a position error signal (PES) to position the head with respect to the selected track, the PES comprising a sequence of PES samples, the disc drive determines a first difference term as a selected combination of a first set of PES samples. A second, subsequent difference term is also generated as a selected combination of a second set of PES samples, the second set of PES samples including at least one PES sample which does not appear in the first set of PES samples. The magnitudes of the first and second difference terms are compared to a predetermined threshold, and a servo defect is detected at such time that both the first and second difference terms exceed the predetermined threshold and the first difference term exceeds the second difference term.

Abstract: A support assembly for supporting a magnetic circuit of a disc drive voice coil motor, the support assembly suppressing the excitation of mechanical resonances in the drive. The disc drive includes a disc and an actuator assembly adjacent the disc, the actuator assembly having a coil of a voice coil motor to which current is applied in order to position a head of the actuator assembly relative to the surface of the disc. The voice coil motor further includes a magnetic circuit comprising a pair of permanent magnets and corresponding magnetically permeable pole pieces disposed above and below the coil. The support assembly suspends the magnetic circuit between a base deck and a top cover of the disc drive and allows cantilevered movement of the magnetic circuit in response to the acceleration of the coil as a result of current being applied to the coil.

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 evaluating the presence of a track tear servo defect in a disc drive, characterized as a stepwise radial discontinuity so that the track ends at a different radius than it begins is disclosed for a disc drive. A first defect log is generated for a selected track, the first defect log providing an indication of detected defects for each servo frame associated with the selected track. At such time that a selected servo frame is identified as having a defect, a second defect log is generated for the selected track while the position information provided by the selected servo frame is ignored. The second defect log is then evaluated to determine whether any defects are detected for the remaining servo frames. At such time that a defect appears in the second defect log for a servo frame immediately following the selected servo frame, a track tear condition is declared.

Abstract: Apparatus and method for detecting defective servo frames in a disc drive, the defective servo frames including anomalous position field patterns which generate burst signals of insufficient relative magnitude to facilitate proper servo control. Burst signals are generated from the position field patterns of a selected servo frame and a combination term is determined as a selected combination of the magnitudes of the burst signals. The combination term is compared to a predetermined threshold and the servo frame is identified as being defective when the combination term falls below the predetermined threshold. The combination term is preferably generated from the magnitudes of burst signals generated from three burst patterns: a first burst pattern extending from a first track boundary to a second, adjacent track boundary, a second burst pattern extending from a track centerline to the first track boundary and a third burst pattern extending from the track centerline to the second track boundary.

Abstract: A corrugated roof support apparatus supportable by underlying support structure is disclosed. A corrugated support substantially aligns with a structural corrugation in a roof panel overlaying the corrugated support. The corrugated support comprises corrugations from a preexisting roof or a new corrugation support secured to underlying support structure, such as a purlin or a spacer member. The roof panel is secured to the corrugated support by way of fastener means, such as self-drilling, self-tapping screws or other through fasteners. The corrugated supports, for new construction, may be secured to the underlying support surface by way of attachment means, such as through fasteners or a locking tab placed in an accommodating slot. Additionally, the roof panel corrugations may be at corrugated panel endlaps, or the panels may comprise a standing seam roof assembly with corrugations in medial portions of the panel.

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.

Abstract: Improved self-synchronization in a sampled magnetic recording channel employing time-domain equalization. The channel includes a time-domain equalizer which filters an input, readback signal to an approximation of a selected target waveform. The equalizer includes a plurality of serially connected analog filter sections having associated tap locations, analog multipliers which multiply the tap signals present at the tap locations by tap weight signals to generate product signals and a summer which sums the product signals to generate an equalized output signal. A self-synchronization circuit, responsive to the main tap of the equalizer, synchronizes the data recovery process used by the channel with the rate of the readback signals provided to the channel.

Abstract: Apparatus and method for improved positional control in a disc drive servo loop, wherein the actual velocity of rotary actuator is sensed from the motion-induced back-emf generated by movement of a coil of the actuator through the magnetic field of a voice coil motor. A current sense resistor is used in conjunction with the coil to provide closed loop control of the current applied to the coil. Signals indicative of the voltages across the serial combination of the coil and current sense resistor are provided to a velocity sense circuit, which determines the velocity of the coil by generating and subtracting out values for the dc voltage drops across the coil and the current sense resistor and the ac voltage drop across the coil. A compensation routine is provided to compensate for variations in temperature of the coil during operation.

Abstract: A method for compensating for position and component induced variations in the acceleration and deceleration capabilities of a voice coil actuator in a disc drive, comprising the steps of dividing the discs radially into a plurality of zones, testing the acceleration and deceleration capability of the disc drive in each zone by performing specially controlled seeks in both inward and outward directions in each zone, comparing the result of these specially controlled seeks with a calculated nominal or desired result, and calculating a compensation factor for each zone which is applied by the servo system to all subsequent seek and track following operations.