Abstract: A disk drive having an electromagnetically actuated latch mechanism for latching and unlatching the movable actuator of the disk drive. The electromagnetically actuated latch has a magnetic circuit structure including a two legged yoke which mounts a coil. A keeper forming part of a latch lever is pivotally mounted for rotation about an axis located beside the yoke structure. The keeper defines two air gaps with the yoke, a variable reluctance air gap with one leg and a substantially constant reluctance air gap with the other leg. A spring biases the latch lever to latched position. In the latched position of the latch lever, the torque couples acting on the latch lever due to flux coupling of the keeper at the variable reluctance gap and the substantially constant reluctance gap, produce torque couples acting in the same direction on the latch lever, minimizing the current requirement to move the latch lever from latched position to unlatch the actuator.

Abstract: In a disk drive, servo gain correction, in the presence of servo code signal variations, is achieved by utilizing the servo position signals to produce a servo gain scaling signal which is combined with the servo position signals to produce a corrected servo position signal for controlling the servo. The disk tracks comprise four phases of servo code, either dedicated or sampled servo code. The servo code is conventionally defined by four phases of recorded magnetic dibits, A, B, C, D. Normal, N, [N=(A-B)] and quadrature, Q, [Q=(C-D)], servo position signals are developed from the recorded dibits, either or both of the normal and quadrature signals may be used for controlling the servo. Absolute value signals N and Q are rectified values of the normal N, and quadrature, Q, signals.

Abstract: A disk pack is clamped between an external flange adjacent one end of a hub and a ring clamp adjacent the other end of the hub. The hub terminates in a tubular section at the location of the ring clamp. The tubular section has substantially cylindrical internal and external surfaces. The ring clamp has a central opening defined by a wall in the ring clamp. The wall of the central opening of the ring clamp is a sliding fit over the substantially cylindrical external surface of the tubular section of the hub. The periphery of a circular expander wedge has an interference fit engagement within the substantially cylindrical internal surface of the tubular hub section. When the circular expander wedge is in place in the tubular section of the hub the tubular section is expanded. The substantially cylindrical external surface of the tubular section is compressed against the wall of the central opening of the ring clamp.

Abstract: A hard disk pack assembly is attached to a motor powered rotatable member in a disk drive by a spring ring. A disk hub mounts one or more disks, functioning as an axial disk spacer when more than one disk is installed. The disk hub has a central circular opening fitted about a cylindrical body on the rotatable member and seats upon a shoulder on the cylindrical body. A spring ring snaps radially inwardly into a circumferential groove in the cylindrical body in a position wedged between surface of the circumferential groove and an upper circular edge of the circular opening in the disk hub to apply axial and radial components of spring force to the disk hub for the purpose of securely seating the disk hub on the shoulder of the cylindrical body and to center the disk hub with respect to the cylindrical body.

Abstract: For cooling a plurality of device modules mounted in an enclosure, a redundant air moving system is coupled to the air duct system of the enclosure. The redundant air moving system has two, three, or more air movers. If one air mover fails, the remaining air mover(s) still provide the required air volume rate for adequate cooling. To make the air movers redundant, they are coupled in parallel to a common air plenum in the air duct system from which ducting to all devices to be cooled is provided. In case of an air mover failure, a flapper door is built into the exhaust path of the air mover. The flapper door is pendulously pivoted in the exhaust path. It is held open by exhaust air flow and is closed by gravity upon cessation of exhaust air flow and held closed by reverse air pressure for the purpose of preventing reverse air flow in the exhaust path, which would disrupt the air pressure in the air plenum and consequently also in the air duct system.

Abstract: A disk drive crash stop/actuator latch combines a crash stop structure with a detent actuator latch which is engaged and latched in a selected radial limit position of the actuator and which is released by the simple expedient of pulsing the actuator motor. The detent actuator latch has a flexible cantilever latch arm secured at one end to the disk drive base. A crash stop face on the distal end of the cantilever latch arm is impacted by a surface on a catch member on the actuator in the radial limit. The cantilever latch arm is bowed between its ends to reduce long column stability to slightly yield to compression loads due to actuator impact. The crash stop face and the surface of the catch member on the actuator are in contact when the detent actuator latch is engaged. A pulse generator coupled to the actuator motor pulses the actuator motor in a sense to drive the actuator away from the crash stop face, overcoming the restraining force of the engaged detent actuator latch.

Abstract: An enclosure for cooling device modules has metered air passages in an air duct system. The device modules which are of the form of air ducts are inserted into the air duct system of the enclosure and have exhaust air passages which are coupled to metered air passages in the air duct system of the enclosure. A source of reduced air pressure which is coupled to the air duct system of the enclosure draws air through the device module into the air duct system of the enclosure via the exhaust air passage of the device module and the metered air passage of the air duct system.

Abstract: A method and apparatus in electrophotographic printing for fusing a toner image onto or into a print medium. A high energy laser beam is projected onto a toner image on a print medium for softening or fusing the toner. Pressure is then applied to the toner against the print medium to permanently fix the toner image onto or into the print medium as a printed image. The high energy laser beam for softening or fusing the toner is synchronized in scan frequency, either at the scan frequency or a whole multiple of the scan frequency, with the low energy image modulated laser beam which scans to photoconductive drum, being reflected from selected facets of a common scanner, or from a selected facet of each of a pair of relatively angularly displaced interconnected scanners.

Abstract: In an elastic coaxial coupler, a cylindrical body of a first member is fitted through an opening in a second member seating said second member upon a flange on the first member. A circumferential groove in the cylindrical body has a conical groove surface confronting a surface of the second member adjacent the opening in the second member. An O-ring in tension around the cylindrical body at the circumferential groove, is drawn into the circumferential groove by the radial force component of the O-ring tension force and is compressed between the conical groove surface and the surface of the second member adjacent the opening in the second member, to securely frictionally engage the second member to the flange of the first member. In an application of this elastic coaxial coupler to a hard disk drive, the first member is the hub of a disk assembly and the second member is the hard disk.

Abstract: An electromagnetic actuator has a U-shaped yoke with substantially parallel legs and a keeper which is pivotally mounted for angular movement about an axis located outside of the yoke to move between two angular positions bridging the yoke legs. The proximal end of the keeper adjacent the pivot has a side face which confronts the end of one pole leg forming a variable length gap called the proximal gap, and, the distal end of the keeper has an end face which confronts a side pole face of the other leg of the yoke forming a gap, called a distal gap, the length of which changes very little between and in the two angular positions of the keeper. The torque constant over the displacement range between the two angular positions of the keeper only slightly changes. The design permits keeper movement through a large angle while minimizing operational current requirements.

Abstract: A test system for a piezoelectric element per se or a piezoelectric element in a physical system, which is subject to forces which deform the piezoelectric element, couples an electrical pulse to the piezoelectric element sufficient to stress the element and induce mechanical ringing upon pulse removal. The ringing electrical signal developed by the piezoelectric element characterizes the functionality of the piezoelectric element. A response circuit which is responsive to the ringing electrical signal provides an electrical signal indicative of the functional condition of the piezoelectric element. The electrical signal is peak detected. The peak detected voltage is compared with a reference voltage to provide an indication of the functionality of the piezoelectric element.

Abstract: To minimize unwanted motion in a hard disk assembly in a hard disk drive, an elastomeric support is employed to mount a hard disk pack for rotation by a motor rotor of a disk spindle motor. The hard disk pack includes a hard disk support ring which has opposite annular axial faces upon which the hard disks are securely mounted and axially spaced thereby. An elastomeric connection between the hard disk support ring and a cylindrical body of the motor rotor of the disk spindle motor, provides a soft, or compliant, support for the hard disk pack.

Abstract: A low insertion force, low profile electrical connector employs the folded end of a planar flexible circuit as the electrical connector plug which is plugged into an electrical connector receptacle having a printed circuit board and printed circuit traces as a part of the electrical connector receptacle. Contact pads connected with flexible circuit traces on the electrical connector plug engage contacts connected to the printed circuit traces in the electrical connector receptacle.

Abstract: A multiple pole, multiple phase, sensorless DC disk spindle motor in a disk drive is powered by direct current which is commutated among the motor phases from a DC power supply to start the motor and to rotate the disks at constant speed in a predetermined direction whenever the disk drive is in use. When the motor is prevented from rotating by the stiction bond of one or more transducers which have adhered to the disks, the direct current is reversibly commutated among the motor phases near the resonant frequency, a predetermined number of times, to produce substantially sinusoidal, bi-polar motor torques to achieve torque amplification to break the stiction bonds. Following the last of the predetermined number of reversible commutations of direct current, direct current commutation is initiated among the motor phases to rotate the motor and the disks in the desired direction at constant speed.

Abstract: A disk drive in which the disk spindle motor for a rotatable recording/reproducing media has a printed circuit stator winding on a printed circuit board within the disk drive housing, fitted between axially spaced circular flanges of a bobbin-shaped motor rotor. Alternately poled, equally circumferential spaced, axial permanent magnet fields between the axially spaced circular flanges link radially disposed printed circuit winding sections. Electronic elements on the printed circuit board are linked internally of the housing with the magnetic head and the actuator motor winding which powers the actuator for moving the magnetic head to different radial locations on the rotatable media. Bi-polar energization of the stator winding of the disk spindle motor is under the control of a commutating circuit controlled by a Hall sensor linked by the axial permanent magnet fields.

Abstract: A heated film die for the fabrication of plastic containers such as bags, envelopes, balloons, bladders, etc.. The die is an integrated sectionalized structure having independent, adjacent, electrically heated, temperature regulated, die sections which are maintained at different temperatures, for performing, simultaneously, two or more of operations such as, cutting, staking and forming, in plastic container fabrication. A lower temperature heat sink between adjacent die sections provides thermal isolation between the die sections.

Abstract: A hard disk drive having an actuator assembly in which only flexible integral load beams are used in the armstack structure. The load beams are assembled in a stack on a tubular actuator member along with the movable coil member of the actuator motor, or other actuator drive mechanism, and after alignment are secured to the tubular member to from a separate actuator assembly. This actuator assembly is applicable to both rotary and linear actuators in disk drives. In the rotary actuator assembly structure, the tubular member or hub is secured to a bearing housing journaled in the base of the drive for rotation about the axis of the tubular member. In the linear actuator structure, the tubular member, is fastened to the moving part of the linear drive mechanism and linearly moves with that mechanism.

Abstract: A hard disk drive, having a removable hard disk stack or assembly in which one or more hard disks are bonded by a compliant bonding agent to a circular hub. Bonding of the hard disk(s) to the hub is the sole support of the hard disks. The circular hub has a center section which is secured by screw threaded attachment to a rotatable member of a motor for rotation at constant speed. The hub center section is of sufficient strength not to deflect in the presence of securing forces. The integrated hard disk(s) and hub provide a hard disk assembly or hard disk stack which, when the hub is attached to the rotatable member, functions as a fixed hard disk assembly providing a fixed, hard disk drive function, while affording ease of removal of the integrated, hard disk assembly for replacement or repair. The hard disk assembly is ideally suited for application in small form factor hard disk drives, less than the 31/2 inch form factor, for example, in the one to two inch form factor range.

Abstract: A thin film magnetic head having a yoke structure comprising a pair of legs, a low reluctance back gap and a high reluctance front gap. The front gap is defined by the pole faces of pole tips which each have a cross-sectional area, in a plane paralleling the pole faces, for limiting magnetic saturation in the yoke structure to regions in the pole tip at and/or adjacent to the front gap. The pole tips define a short throat at the front gap to increase flux density at the gap and each yoke end face or pole tip has a thickness measured in the direction across the front gap which is greater than the thickness of either leg.

Abstract: A rotary actuator disk drive in which the rotary actuator is driven by a motor comprising a movable coil and a stationary permanent magnet structure producing a magnetic field which links the coil. The rotary actuator comprises a load beam arm stack and a voice coil arm of electrical insulating material such as a light weight plastic, all of which are axially stacked and swaged to a rotary actuator bearing hub which is rotatably mounted in the disk drive. The coil arm of electrical insulating material has a bobbin section on which the coil is directly wound. The coil arm is molded together with the coil arm mounting bushing, a latch pin of magnetic material and an actuator arm balance weight insert molded therein. The latch pin is linked by the permanent magnet field of the motor permanent magnet structure and functions with that structure to define mechanical limits of angular actuator movement and to magnetically latch the actuator in one angular limit when the disk drive is not in use.