Abstract: A phase comparator generates a reference pulse equal in duration to one bit cell, and a variable pulse having a duration representative of the duration and time displacement of the leading edge of a data pulse from the center of the bit cell. The phase comparator includes two D-type flip-flops arranged so that the variable pulse is initiated by the leading edge of the data pulse in the one bit cell, the reference pulse is initiated by the edge of the clock pulse at the end of the one bit cell, and both pulses are terminated by the edge of the clock pulse at the end of the next bit cell. Hence, only clock edges at the bounds of the bit cell affect the pulse durations and the apparatus is insensitive to clock asymmetry.

Abstract: A vent cap has a long, narrow air communication passage covering the vent outlet of a sealed disk drive. The passage reduces diffusion of water vapor into the disk drive.

Abstract: Apparatus for assembling a pair of high strength magnets and the common pole piece into a unit for use in a disk drive includes a bed with a channel in which the magnets can slide or translate, and a stop centrally located in the channel to prevent execessive impact between the magnets as they slide under the force of mutual attraction toward each other. A recess in the bottom of the channel below the stop is adapted to receive the pole piece, and the attractive force between the pole piece and the magnets firmly attaches the magnets to the pole piece in the desired location after they have been properly positioned with respect to the pole piece by interaction of the stop and channel walls with the magnets.

Abstract: A probe head for vertical recording includes a U-shaped member partially surrounding the probe and a coil supported by the U-shaped member. When the coil is energized, flux from the probe is focused to the region between the legs of the U-shaped member to greatly increase flux gradient during a write operation.

Abstract: In a disk cartridge having a housing containing a rotatable data storage disk and hub assembly, the hub having a centered circular plate portion accessible through a housing aperture, a disk cover collar having a flexible removable bottom cover supported by the housing to cover the housing aperture and having an annular ring portion which provides a confinement ring for centering the hub and data storage disk as the disk cover collar flexes during normal handling of disk cartridge.

Abstract: A method and article of manufacture allows great accuracy in machining the edge of a face on a prism to a predetermined position respective a feature carried on the face and formed by deposition of insulating material. The preferred application for this invention is in accurately machining the transducing surface of a disk memory transducer assembly so that the throat height of the thin-film head carried on an end face of the assembly has a precise value.

Abstract: A decoder for the 2,7 variable length code. A four-bit shift register sliding block decoder detects the presence of the code's four-bit ending sequence and provides decoded binary output. The decoder has only a three-bit binary error propagation.

Abstract: This invention provides a structure for damping longitudinal vibrations in an apparatus which moves longitudinally.It employs, in a longitudinally moveable body, a structural element, slotted in the longitudinal direction, so that said structural element has relatively rigid upper and lower portions and relatively flexible flextures at the slot ends. A layer of elastomeric material covers a side of said element and a stiffening plate covers said elastomeric layer.

Abstract: A circuit for phase locking a clock signal to a series of data pulses includes a wide band signal generator, a power supply, a flip-flop, a loop filter and a voltage controlled oscillator ("VCO"). The circuit adds current or subtracts current from the loop filter which controls the voltage across the VCO. The voltage across the VCO determines the frequency of the clock signal which it outputs. During the PLO sync zone, the circuit adds or subtracts increased amounts of current from the loop filter during every other pulse to cause greater amounts of correction in the frequency of the clock signal during every other pulse. The wide band signal generator, which includes a component which decays over time, operates only during the PLO sync zone. The circuit uses a flip-flop triggered by each data pulse to either send the current from the wide band signal generator to ground or add it to the constant current level produced by the power supply.

Abstract: This invention describes a means and method for moving an arm in precise angular increments to a degree of precision far beyond the capacity of a normal reduction gear assembly acting at the impetus of a stepper motor. At rest a set of paired and unequal high precision gear sets hold the member in place. To accomplish movement, they are decoupled and a normal reduction gear mechanism is employed to drive the member to the approximate location desired. The more precise location of the member is accomplished by the recoupling the high precision gear sets. Thus, without high precision movement a high precision location is attained.

Abstract: A high velocity seek deceleration technique is disclosed for seek operations of disk drives wherein measured time per track is compared to a predetermined time per track in a memory as indexed by number of tracks to end of seek determines an error value which adjusts a deceleration amplifier. The gain of digital output to the amplifier is adjusted depending on the number of tracks to end of seek, the higher the number, the higher the gain. Further, a variable bandwidth filter is employed to increase bandwidth as velocity decreases.

Abstract: A gas laser optical recording apparatus having a write beam deflected from the optical path taken by the read beams by an acoustic optical modulator. In one embodiment the write beam is time-shared between the read optical path and the write optical path. In this embodiment an attenuator is placed in the read optical path to reduce the power of the laser beam from write power to read power. In a second embodiment 5 percent of the power is allowed to remain in the read optical path and the write beam is deflected between a beam stop and the write optical path as required.

Abstract: Apparatus is shown for mixing an epoxy adhesive. An epoxy resin and its associated curing agent are simultaneously loaded from separate cartridges into a length of flexible PVC tubing, part of which is contained between a rotor and a stator. Bearings, mounted rotatably about the rotor, engage and travel along the tubing as the rotor is revolved, each bearing compressing the tubing at its point of engagement. The tubing, repeatedly compressed and released by each bearing in succession, kneads the epoxy resin and curing agent into a homogeneous mixture.

Abstract: A vertical recording head includes a W-shaped core, a substrate carrying a thin film probe supported in one slot of the core, and a shield coil wound in the slots to hold the substrate and assemblage together. A non-magnetic cap forms the surface of the head over the cap, with the arrangement being such that the probe extends through the cap so the magnetic gap is as small as possible.

Abstract: A fan is disclosed that contains cut-outs that reduce the noise levels. The fan is used to cool circuit boards.

Abstract: A construction for actuator assemblies is disclosed using a material of low permeance as a structural element, included normal to the axis of coil movement to lower coil inductance by reducing reactance flux in support structures and providing a channel for eddy currents set up in response to coil reactance. The net result is enhanced coil responsiveness to energization.

Abstract: An improved rotary read/write head assembly is particularly suitable for use with a vertical format magnetic recording medium such as tape in a magnetic recording system. A rotary element of the assembly carries a plurality of main poles whose tips are at an edge of the rotary element and kept in substantially contacting relationship with the medium. Rotation of the element causes the pole tips to successively sweep across the medium and sequentially function as the main pole of a probe head.

Abstract: A disk cartridge assembly includes a rotatable magnetic disk enclosed within a rectangular cartridge. Attached to the top and bottom covers of the cartridge are a plurality of leaf springs which urge the top and bottom sections toward and against one another. Resilient cloth liners are mounted to the inside surfaces of the top and bottom covers. As the leaf springs urge these sections toward one another, the liners engage the disk surface to prevent the disk from moving freely within the cartridge. The leaf springs are flexible in the axial direction but rigid in the radial direction, thus to maintain the top and bottom sections in alignment with one another.

Abstract: A process for chemically bonding a lubricant to a magnetic disk by applying a functionalized polymeric lubricant to the disk, heating it until a significant portion bonds to the disk via the functional terminal group, and then reacting the unbonded residue with a chemical moiety, the residue then forming a mobile lubricant highly resistant to spin-off due to the presence of the bonded lubricant.

Abstract: An improved rotary read/write head assembly is particularly suitable for use with a vertical format magnetic recording medium such as tape in a magnetic recording system. A rotary element of the assembly carries a plurality of main poles whose tips are at an edge of the rotary element and kept in substantially contacting relationship with the medium. Rotation of the element causes the pole tips to successively sweep across the medium and sequentially function as the main pole of a probe head.