Patents Represented by Attorney, Agent or Law Firm John C. Chen
  • Patent number: 5575355
    Abstract: A method, and associated apparatus, or applying fluid lubricant to hydrodynamic bearing. Clearance spaces of the bearing which are to be filled with the fluid lubricant are evacuated. The fluid lubricant is then applied to the clearance spaces. Once the fluid lubricant has been applied to the clearance spaces, or concurrent therewith, the clearance spaces are returned to ambient pressure levels. Any pockets of air, or other gas, trapped within the bearing are collapsed as the clearance spaces are returned to the ambient pressure levels. The method is amenable to a high volume, assembly line-like process wherein large numbers of bearings may be filled with the fluid lubricant in a short period of time. A conveyor conveys the bearings into a pool of fluid lubricant in a vacuum tank having a pressure level adjustable between an ambient pressure level and an evacuated pressure level, through the pool of fluid lubricant, beyond the pool, and out of the vacuum tank.
    Type: Grant
    Filed: April 3, 1996
    Date of Patent: November 19, 1996
    Assignee: Quantum Corporation
    Inventors: Carl D. Williams, Jackie Cordova, Richard E. Mills
  • Patent number: 5555211
    Abstract: A spindle shaft attachment technique for a disk drive includes a conical tip formed on, or added to, the top of the spindle shaft in order that it might be embedded in or contact a substantially planar, interior surface of the HDA cover at a location determined by the perpendicularity of the spindle as set by the baseplate without forcing the top of the spindle shaft to a predetermined screw hole or recessed cone location on the cover. The spindle shaft attachment technique disclosed allows for use of a relatively longer spindle shaft for a given height form factor drive and, therefore, allows a greater spacing between upper and lower spindle bearings resulting in greater stiffness and an increased rocking mode frequency.
    Type: Grant
    Filed: January 23, 1995
    Date of Patent: September 10, 1996
    Assignee: Quantum Corporation
    Inventor: Frank W. Bernett
  • Patent number: 5553086
    Abstract: Plural embedded servo sector sets are written as a single operation by a servo writer during manufacture of a hard disk drive. Later, the disk drive electronics performs a self scan and selects one good set of embedded servo sectors and erases all other sets, thereby decreasing the number of servo sector rewrites during manufacture and reducing manufacturing time and costs.
    Type: Grant
    Filed: January 28, 1994
    Date of Patent: September 3, 1996
    Assignee: Quantum Corporation
    Inventors: Mark A. Sompel, William W. Clawson, Jason Hong
  • Patent number: 5532884
    Abstract: A deflection mirror tower (DMT) of a multiple-disk array, optical storage system includes a plurality of prism members, each having an angular mirror surface, arranged along a vertical axis of the DMT and configured at a predetermined angular orientation to deflect a laser beam to a respective disk surface. The DMT is generally fabricated using a two-level partitioning process. Several prepared glass substrates, i.e., one for each mirror type, are initially sliced into bars having predetermined geometries. A bar from each substrate is sequentially aligned to a master reference and bonded to adjacent bars to form an intermediate bar stack. The stack is then segmented into a plurality of DMT components, each having a plurality of prism members.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: July 2, 1996
    Assignee: Quantum Corporation
    Inventors: Neville K. Lee, Amit Jain, Roy E. Martin
  • Patent number: 5523904
    Abstract: A method of adjusting the lateral position of writing on a magnetic tape. A magnetic tape recording is provided having a first track including alternate data and servo information wherein the data is written at a first azimuth angle and the servo information is written at a second azimuth angle, and having a second track including alternate data and servo information wherein the data is written at the second azimuth angle and the servo is written at the first azimuth angle. The first track is monitored during writing of the second track for the presence of servo blocks. Writing in the second track is interrupted upon the sensing of alternate servo blocks in the first track. Amplitudes of servo blocks received during writing are compared with amplitudes of alternate servo blocks received while writing is interrupted, and the lateral position of writing is adjusted in response.
    Type: Grant
    Filed: June 24, 1994
    Date of Patent: June 4, 1996
    Assignee: Quantum Corporation
    Inventor: George A. Saliba
  • Patent number: 5499161
    Abstract: A flexible circuit assembly to provide communication to and from data transducer heads located on a load beam of a suspension assembly of a disk drive. Two discrete preamplifier integrated circuits, one of which has a pin-out that is a mirror image of the other, are mounted on a flexible circuit substrate such that the mirror image preamplifier integrated circuit mounted thereon folds underneath the first preamplifier integrated circuit. A head-arm access strip of the flexible circuit is installed in a distorted S-shaped bow in order to reduce the force on the suspension assembly.
    Type: Grant
    Filed: February 18, 1994
    Date of Patent: March 12, 1996
    Assignee: Quantum Corporation
    Inventors: Ali Hosseinzadeh, Maziar Amirkiai
  • Patent number: 5497113
    Abstract: A transmission line driver circuit has active pullup and pulldown N-type field-effect transistors (N-FETs). An input stage employs a group of N-FETs and a group of P-type field-effect transistors (P-FETs) both being dimensioned and configured to yield a variable-slope switching characteristic for both high-to-low and low-to-high signal transitions. In the N-FET group, one N-FET has the same threshold voltage as the pulldown N-FET, is diode-connected, and is also connected in parallel with a substantially smaller N-FET. In the P-FET group, one P-FET is connected in parallel with a substantially smaller P-FET, and receives a buffered version of the output signal. Both the larger N-FET and larger P-FET conduct for only part of the respective signal transition during which they are active, so that each edge has two distinct slopes. The driver circuit also includes a differential amplifier connected in feedback configuration with the pullup N-FET to limit the maximum transmission line voltage.
    Type: Grant
    Filed: May 16, 1994
    Date of Patent: March 5, 1996
    Assignee: Quantum Corporation
    Inventor: Richard Uber
  • Patent number: 5494473
    Abstract: The invention provides a new method and apparatus for electrically accessing a lapping sensor positioned along a row of slider sites on a wafer. The apparatus for accessing the lapping sensor may be positioned outside of the boundaries of the slider sites. The apparatus may also provide top conductors electrically connecting target pads to contact pads. The process for lapping rows of slider sites includes coupling a measurement device to a target pad, coupling a lapping sensor to the top conductor, and lapping the row until the measurement device detects a predetermined signal from the lapping sensor.
    Type: Grant
    Filed: July 7, 1993
    Date of Patent: February 27, 1996
    Assignee: Quantum Corporation
    Inventors: David J. Dupuis, David J. Kindler, Alan B. Smith
  • Patent number: 5486970
    Abstract: A cleaning apparatus for cleaning a read/write head of a data storage disk. The cleaning apparatus comprises a mounting base mounted adjacent to the disk. The base includes a rachet mechanism for rotating a cleaning pad. The ratchet mechanism is activated by an actuator arm for positioning the read/write head as the arm moves the read/write head across a cleaning surface of the pad. A loading ramp is used to vertically position the head relative to the cleaning pad, The ratchet mechanism can be used with either a rotary or linear actuator. The cleaning pad can have a brush with bristles, or a foamed backed cloth. The cleaning pad is particularly suited for read/write heads having a grooved air-bearing surface likely to collect dust.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: January 23, 1996
    Assignee: Quantum Corporation
    Inventors: Neville K. Lee, Hisashi Katao
  • Patent number: 5474253
    Abstract: The present invention is an apparatus for controlled, uniform stacking of tape thereon during read/write operations in tape drives to reduce lateral tape motion during read/write operations. The invention comprises a hub and two flanges that are located on opposite sides of the hub. The flanges have surfaces facing each other extending outwardly from the hub in diverging relationship with each other. The separation between the facing surfaces of the flanges increases from a minimum at a location adjacent to the hub to a maximum at the outer circumferential edge of the flanges in a radial direction extending outwardly from the axis of rotation. Further, the separation between the facing surfaces also increases from a minimum to a maximum along any path of equal distance around the axis of rotation, the location of minimum separation is generally opposite to the location of maximum separation.
    Type: Grant
    Filed: October 12, 1993
    Date of Patent: December 12, 1995
    Assignee: Quantum Corporation
    Inventors: Kumaraswamy Kasetty, George Saliba