Abstract: A circuit for providing a control voltage to a switch includes a capacitor, a first pair of switches for coupling the capacitor to an input voltage source and a second pair of switches for coupling the capacitor to the switch. The first pair of switches is controlled by a control signal in response to the voltage across the capacitor in order to prevent overcharging the capacitor beyond a first predetermined level. The second pair of switches is controlled by a second control signal in response to the voltage across the switch in order to replenish the capacitor voltage when the capacitor voltage falls to a second predetermined level. The first and second pairs of switches are closed during non-overlapping time intervals in order to isolate the switch from the input voltage source, thereby preventing switching transients from affecting the input voltage source and permitting the circuit to be used to drive a variety of switch types arranged in a variety of configurations.

Abstract: A lapping monitor for monitoring the lapping of a lapping surface of a body having at least one transducer which has a height that has to be lapped. The lapping monitor has a lap unit for lapping the lapping surface, at least one lapping indicator mounted close to the transducer to indicate the height of the transducer and a control block in the body at a certain distance from the lapping indicator or indicators. It is also possible to use a property of the transducers themselves, e.g., their resistance, to indicate their height. The control block receives indication of the height of the transducers being lapped from the lapping indicators or from the transducers via an electrical connection. The control block is further equipped with test contacts for establishing an external connection.

Abstract: Flying height Adjustment for Air Bearing Sliders An air bearing slider for sliding over a medium surface of a recording medium and having an air bearing surface facing the disk surface, a back surface perpendicular to the air bearing surface and a head at the back surface. During operation the head is maintained at a flying height above the disk surface with the aid of a flying height adjustment mechanism consisting of one or more ducts, each having an inlet at the air bearing surface and an outlet at the back surface. A valve mechanism controls an air flow through the duct or ducts by opening and closing the valve or valves together or independently. Alternatively, a deformable surface feature located on the back surface of the slider is used to alter the air flow to thus control the flying height. The mechanism of the invention allows one to achieve accurate flying height control in a range between 5 and 50 nm and between 0 nm and 15 nm as required for near-field or contact disk drives.

Abstract: A rotary microactuator includes a stationary structure formed on a substrate, a movable structure, and at least a pair of wires connected to the movable structure that conduct a signal associated with the movable structure. Each wire of the pair of wires has a first end that is connected in a cantilever manner to the substrate and a second end that is connected to the movable structure. The wires each have a serpentine shape between the first end and the second end, a predetermined spring stiffness, and a predetermined electrical characteristic. The microactuator also includes a magnetic head slider that is attached to the movable structure, and at least another pair of wires conducting a signal associated with a magnetic head of the slider. Each of the another pair of wires has a first end that is connected in a cantilever manner to the substrate and a second end that is connected to the movable structure.

Abstract: A bistable micromechanical switch that includes a substrate, at least two anchor points formed on the substrate, and a beam structure that includes a two-material beam attached to at least two anchor points. The two-material beam has a first portion, a second portion and a center portion. The first portion of the two-material beam is formed from a first layer of a first material and a second layer of a second material such that the first layer of the first portion is proximate to the surface of the substrate and the second layer of the first portion is remote from the surface of the substrate. The first material has a first coefficient of thermal expansion and the second material has a second coefficient of thermal expansion such that the second coefficient of thermal expansion is greater than the first coefficient of thermal expansion.

Abstract: A apparatus and method of using the apparatus for removing a blockage in a subsea pipeline without retrieval of the pipeline to the surface. The apparatus components include a hot tap saddle, a drill assembly, a fluid blaster assembly and a support frame. The hot tap saddle component has a first portion and a second portion, with the first and second portions being configured to clampingly engage in a sealing relationship to the subsea pipeline. The first portion of the saddle includes a first and second opening with the first opening extending generally upwardly and configured for connecting to a drill assembly and the second opening being positioned generally at an angle to the first opening and configured for connecting to a fluid blaster assembly. The fluid blaster assembly including a nozzle, a hose and a high pressure pump with the fluid blaster assembly being contained within a pressure vessel. The fluid blaster assembly is configured for mounting to the second opening of the hot tap saddle component.

Abstract: A method and apparatus for controlling a multiple-stage actuator for a disk drive which does not require an additional sensor for measuring the relative position between adjacent actuator stages. In a two-stage actuator system, a position-type secondary actuator (SA) rides piggyback on a primary actuator (PA). The repeatable runout is measured and used as a feedforward signal to the PA. If the PA is a rotary actuator, the feedforward signal is preferably arc corrected for the arc that the head transverses from the inner radius to the outer radius of the disk. Added to the feedforward signal is the moving average of the drive signal applied to the SA. Because the SA is of the position-type having a neutral position, this moving average is proportional to the time cumulative drift present in the two-stage actuator system, and forces the PA in a direction that minimizes deviation of the SA from its neutral position.

Abstract: A method and apparatus for controlling a multiple-stage actuator for a disk drive which does not require an additional sensor for measuring the relative position between adjacent actuator stages. In a two-stage actuator system, a position-type secondary actuator (SA) rides piggyback on a primary actuator (PA). The repeatable runout is measured and used as a feedforward signal to the PA. If the PA is a rotary actuator, the feedforward signal is preferably arc corrected for the arc that the head transverses from the inner radius to the outer radius of the disk. Added to the feedforward signal is the moving average of the drive signal applied to the SA. Because the SA is of the position-type having a neutral position, this moving average is proportional to the time cumulative drift present in the two-stage actuator system, and forces the PA in a direction that minimizes deviation of the SA from its neutral position.

Abstract: A microfabricated wobble motor with a positioning arm attached to the wobble motor rotor acts as a fine positioner with bidirectional movement. The primary application is a rotary actuator for the read/write head in a very small magnetic recording disk drive. An integrated head-arm assembly is attached at one end to the rotor of the wobble motor. The other end of the head-arm assembly has a head carrier that is maintained in contact with the disk. Head position error information is read from the disk and used to provide control signals to each of the stator elements. The stator elements are sequentially addressed by applying a voltage from a driver circuit. This causes the rotor to be electrostatically attracted to the activated stators, so that the rotor is movable bidirectionally. The read/write head can thus be moved bidirectionally to any of the data tracks on the disk and maintained on a desired data track for reading or writing data.

Abstract: A magnetic recording disk drive with a magnetoresistive (MR) read sensor or head has a shock and vibration detection circuitry responsive to a thermoresistive signal contained in the signal from the head. The MR head is heated by an electrical bias current and is supported on the head carrier near the surface of the disk. External shock or vibration to the disk drive alters the spacing between the carrier and the disk, which causes fluctuations in the head temperature due to cooling of the heated head by the disk. These temperature fluctuations are reflected in the signal from the head as a thermoresistive signal comprising modulation of a baseline voltage level. The shock detection circuitry compares positive and negative excursions of this thermoresistive signal with a predetermined threshold voltage level. When the threshold is exceeded, indicating an external shock or vibration in excess of an allowable limit, writing of data is inhibited.

Abstract: A contact recording disk file uses an integrated head-suspension assembly having a head carrier with a dual-layer wear pad for contacting the disk during read and write operations. The outer wear layer of the pad is relatively soft and wear prone compared to a harder and more wear-resistant inner layer. The outer wear layer wears away at a relatively rapid rate during initial wear-in of the head carrier. In this manner the head pole pieces, which extend into the wear pad, are rapidly put into contact with the disk, thereby compensating for initial misalignment of the wear pad with the surface of the disk. The inner wear layer then provides wear resistance over the life of the disk file. In the preferred embodiment, both the outer and inner wear layers are formed of essentially amorphous carbon doped with different amounts of hydrogen.

Abstract: A cable ski binding comprised of a toe iron having a boot sole support and boot toe lateral movement side restraint surfaces, a toe bail for clamping the top surface of the toe end of the sole extending out from the toe end of the boot to the sole support plate, a cable for securing the boot between the said lateral side restraints and under the said toe bail, a dual purpose heel assembly having a heel lever for securing the cable to the heel of the boot and a rocker means with two opposing elongate members, one of which acts against a spring and the other having a near horizontal surface aspect and attached to the rear most end of the cable loop. Sufficient stress on the cable causes the rocker to rotate and thus allows for the effective lengthening of the cable relative to the length of the boot while being continuously opposed by an increasing torque applied to the rocker by the spring through the moment arm of the former elongate member.