Patents Examined by James T. Wilson
  • Patent number: 5424884
    Abstract: A disk device with a cleaning device and a cleaning method according to the present invention include cleaning motor control means for rotating a disk oppositely to a direction of rotation of the disk in recording and regeneration, and seeking means for forcing a slider to seek the disk over a whole recording region during the opposite rotation of the disk to permit any dust to adhere to the slider, whereby a motor is started and stopped (contract-start-stop) after cleaning the recording region, so as to force the dust adhering to the slider to fall on a disk surface for cleaning the slider.
    Type: Grant
    Filed: September 30, 1993
    Date of Patent: June 13, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Takashi Nonaka
  • Patent number: 5420730
    Abstract: A method and apparatus are provided for recovering servo information in a disk drive for positioning a data transducer head relative to concentric data tracks wherein the head reads user data encoded in a predetermined data code and reads servo information within plural servo sectors embedded in each data track defined on a storage surface of a rotating disk. The data tracks are arranged in plural groups of concentric tracks within concentric zones wherein each zone has a user data transfer rate selected in relation to disk radius, the servo information being recorded in at least three patterns within each embedded servo sector: a servo sync pattern, a user data code violating pattern, and a servo data bit pattern.
    Type: Grant
    Filed: January 11, 1994
    Date of Patent: May 30, 1995
    Inventors: Ronald R. Moon, Daniel E. Barnard
  • Patent number: 5420729
    Abstract: Automatic head cleaning apparatus and method for checking insensitivity of a VCR video head and for performing a head cleaning operation for a predetermined period. When the insensitivity of the video head is not corrected even after the head cleaning operation for the predetermined period, the VCR tape is ejected. Simultaneously, an alarm notifying a failure of the VCR is activated. A VCR head cleaner is also provided that is in close contact with a VCR drum head due to a magnetic reluctance force during the head cleaning operation. The VCR head cleaner prevents the video head from being subjected to adverse impact and frictional force, and is easily installed requiring no additional space within the VCR. Furthermore, the cleaning operation is automatically completed.
    Type: Grant
    Filed: August 16, 1994
    Date of Patent: May 30, 1995
    Assignee: Gold Star Co., Ltd.
    Inventors: Byung H. Lee, Man S. Park, Jong H. Kim
  • Patent number: 5420724
    Abstract: A computer is connected to VTR units and a CRT monitor through lines. Each of the computer and the units to be controlled thereby is provided with a clock means for sharing the same time. The computer sends to the VTR unit a command for releasing record pause state and starting the record operation at time T1. After the VTR unit started the record operation, when the counter value became x, the VTR unit sends time Tx to the computer. The computer computes formulaD=Tx-T1-xso as to obtain delay time D. In determining the present tape position of the VTR, the computer obtains data of counter value Pc and time Tc from the VTR, and assigns the present tape position Pn of the VTR using the formulaPn=Pc+(Tn-Tc),where Tn is the time at which the controller receives the signal from the VTR.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: May 30, 1995
    Assignee: Sony Corporation
    Inventors: Harumi Kawamura, Hisato Shima, Naoki Nagano
  • Patent number: 5416648
    Abstract: A hard disk drive spindle synchronization method comprises the steps of: sending an index marker pulse generated within each disk drive to mark in time a beginning of each rotation of the disk spindle thereof to a party line to which all drives are connected, rotating the disk spindle at a slightly different rotational velocity than any other drive of the array, monitoring drive pulses present on the spindle reference party line from other disk drives of the plurality to locate a center of gravity of pulse clusters which is within approximately plus or minus one quarter revolution of the drive's own index marker pulse, upon detection of a said center of gravity, ceasing to rotate the disk spindle at a slightly different rotational velocity during a second phase, adjusting the rotational phase of each drive to converge toward the center of gravity until all drive pulses present on the spindle reference party line converge into a single composite marker pulse present on the spindle reference party line, and mai
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: May 16, 1995
    Assignee: Quantum Corporation
    Inventors: David B. Jeppson, Benjamin M. Miller
  • Patent number: 5410439
    Abstract: The invention produces and maintains clearance and glide test results for a disk file, stores these results, and monitors head clearance and disk asperities over the useful life of the file using native disk file electronics. The disk file includes a predictive failure analysis component which utilizes clearance and glide test results to predict impending failure of a disk in the disk file.
    Type: Grant
    Filed: February 22, 1994
    Date of Patent: April 25, 1995
    Assignee: International Business Machines Corporation
    Inventors: Gary T. Egbert, Hal H. Ottesen, Gordon J. Smith
  • Patent number: 5404252
    Abstract: A movable head position controlling device for magnetic recording and reproducing apparatuses. The position of a magnetic head is detected. The magnetic head is driven by an actuator in accordance with a driving signal. The driving signal is corrected on the basis of the estimated speed of the magnetic head, the absolute height of the movable head, the displacement of the magnetic head, or the output of an equivalent coil. The speed of the magnetic head is estimated by a speed estimating observer. The absolute height is detected by a magnetic field detecting element. The displacement of the magnetic head is detected by non-contacting sensors attached to a member which moves together with the magnetic head and a member which does not move together with the magnetic head, respectively.
    Type: Grant
    Filed: April 14, 1993
    Date of Patent: April 4, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masato Nagasawa, Eiji Yokoyama
  • Patent number: 5404253
    Abstract: In a disk drive controller, a head position servo compensates for repetitive runout disturbances arising from displacement of the center of the concentric data storage tracks from the axis of rotation of the disk. An estimator model is provided which includes first and second runout parameters for emulating the sinusoidal runout disturbance at a period that is the same as the rotational period of the disk. The runout parameter values generated from the model are stored in a reference table and used during read/write operations to adjust compensator-generated command signals in order to compensate for repetitive runout. Alternatively, an estimator including the runout parameters is operated in real time to provide estimated state signals as feedback signals for the servo system.
    Type: Grant
    Filed: June 24, 1993
    Date of Patent: April 4, 1995
    Assignee: Fujitsu Limited
    Inventor: Christopher L. Painter
  • Patent number: 5404251
    Abstract: A system is provided which records reproduces signals on/from a magnetic tape in a cassette in longitudinal tracks in two track patterns in two adjacent tape zones which are inscribed/read in opposite directions. The cassettes are non-reversible and comprise one imperforate main wall. Without exception the associated apparatuses comprise, as a standard feature, recording/reproducing signals in the two opposite directions without reversal of the cassette. The system may be constructed as a two-standard system suitable for use with both reversible and non-reversible cassettes in conformity with non-compatible standards on two-standard apparatuses.
    Type: Grant
    Filed: September 2, 1993
    Date of Patent: April 4, 1995
    Assignees: U.S. Philips Corporation, Polygram International Holding B.V.
    Inventors: Jozef Duurland, Bernard H. Timmer, Norbert C. Vollmann
  • Patent number: 5402287
    Abstract: In the head positioning apparatus of a disk-shaped information recording medium using the sector-servo-method, track codes are recorded in advance so as to be repeated every 12 tracks in the servo sectors of the disk-shaped information recording medium, the track are reproduced with a head, and a distance between the current position of the head and a target track is detected from the reproduced signal of the track codes with a resolution of 1/2.sup.7 of track width, then the head is moved to the target track so as to decrease the distance, when the head reaches the range of the width of .+-.6 tracks of the target track, an expanded head position signal having the resolution of 1/2.sup.7 is generated, and the head is controlled on the basis of the expanded head position signal and is finally settled to the target track.
    Type: Grant
    Filed: July 18, 1991
    Date of Patent: March 28, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Ryosuke Shimizu, Tetsurou Takaoka, Tsukasa Yoshiura, Noriaki Wakabayashi
  • Patent number: 5396380
    Abstract: Track codes are recorded in advance so as to be repeated every 12 tracks, and burst signals .alpha. and .beta. are also recorded in advance so as to be repeated every 2 tracks, in the servo sectors of the disk-shaped information recording medium; the track codes and the burst signals .alpha. and .beta. are reproduced with a data head, and a distance between the current position of the data head and a target track is detected from the reproduced signal of the track codes with a resolution of 1/2.sup.2 of track width, then the data head is moved to the target track so as to decrease the distance; when the data head reaches the range of the width of .+-.6 tracks of the target track, an expanded data head position signal having the resolution of 1/2.sup.2 is generated; and thereby the data head is controlled.
    Type: Grant
    Filed: July 15, 1991
    Date of Patent: March 7, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Ryosuke Shimizu, Tetsurou Takaoka, Tsukasa Yoshiura, Noriaki Wakabayashi
  • Patent number: 5396379
    Abstract: A disk storage system having a mechanism for minimizing effects of slip/stick in a disk drive head assembly. A transducer is used to read data from and write data to a rotating disk. An actuator assembly holds the transducer. The actuator assembly is comprised of a load member onto which a flexure is attached. A slider is mounted onto the flexure. The transducer is mounted onto the slider. In this manner, the transducer can pitch and roll to maintain a constant height in reference to the disk's surface. A servo mechanism controls the acceleration and deceleration of the head according to a predetermined seek profile specifying how the transducer is to be moved for a particular seek. As the transducer approaches the destination track, the profile calls for a sudden deceleration surge in order to compensate for misalignments occurring during the seek due to the flexure slipping laterally in reference to the load member and sticking in that position because of friction.
    Type: Grant
    Filed: November 20, 1992
    Date of Patent: March 7, 1995
    Assignee: Maxtor Corporation
    Inventor: Mike J. Mayo
  • Patent number: 5377056
    Abstract: A digital tape reading device comprises an arrangement wherein when a buffer full signal is generated the tape continues to move until the end of a group of data. When buffer space becomes available, the device recovers the tail end of the group of data. Upon reaching the end of the group of data, the device repositions the tape to the beginning of the group to recover only the unread data, skipping the previously read data.
    Type: Grant
    Filed: March 6, 1992
    Date of Patent: December 27, 1994
    Assignee: Hewlett-Packard Company
    Inventor: Kevin L. Jones
  • Patent number: 5371939
    Abstract: In positioning a transducer head with respect to a supporting arm, the transducer head is subject to both a normal force and a moment force and has first and second air bearing surfaces. The apparatus includes a controller and first and second sensors for detecting the overturning moment and being adapted for providing data representative of the overturning moment to the controller. A first actuator varies the position of the load arm and a second actuator varies the position of the transducer head. The first and second actuators act in concert to negate the overturning moment. A third sensor detects the position of the first air bearing surface with respect to a known level reference and a third actuator positions the first air bearing surface of the transducer head. A fourth sensor detects the position of the second air bearing surface with respect to a known level reference and a fourth actuator positions the second air bearing surface of the transducer head.
    Type: Grant
    Filed: July 8, 1993
    Date of Patent: December 13, 1994
    Assignee: Martronics, Inc.
    Inventors: James J. Ressmeyer, Lloyd C. Goss
  • Patent number: 5363255
    Abstract: A diskette comprising a jacket, a liner material disposed within said jacket, a flat circular media having a magnetic coating on both sides disposed within said liner material, a hub attached at the center of said media, a plurality of optical positioning tracks on at least one of said sides of said media, and a media type code optically embossed on at least one of said sides of said media. The media type code contains information about the physical properties of the particular diskette that will allow a disk drive unit to auto-configure itself to allow optimum data communication and performance.
    Type: Grant
    Filed: March 16, 1993
    Date of Patent: November 8, 1994
    Assignee: Insite Peripherals, Inc.
    Inventors: Michael L. Ivers, Andrew M. Rose, Alton B. Otis, Jr.
  • Patent number: 5359473
    Abstract: A digital tracking device for use in a helical scan type magnetic recording and reproducing apparatus with an ATF system utilizing four-frequency pilot signals includes a sampling circuit which samples reproduced pilot signals with a frequency of a predetermined one of the four pilot signal frequencies, digital filter circuits for deriving aliasing signal components of the predetermined pilot signal produced by the sampling circuits, and a feedback circuit for feeding back a tracking error signal corresponding to signal levels of the aliasing signal components derived by the digital filter circuits to a magnetic tape drive system of the recording and reproducing apparatus.
    Type: Grant
    Filed: September 15, 1993
    Date of Patent: October 25, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kaniwa, Hideo Nishijima, Toshio Nakamoto, Koichi Ono
  • Patent number: 5359474
    Abstract: A system for the sub-micron positioning of a read/write transducer (28) of a disk drive whereby motion of the transducer, fixed to a transducer holder (30), is caused by a flexing beam (26) deflected by an input spring (32) in turn deflected by an input actuator (34). Motion of the transducer is significantly less than the deflection of the input spring, significantly increasing system resolution while decreasing positioning errors and inaccuracies. The geometry and materials of the flexing beam (26) are such as to promote bending only in a preferred plane parallel to the disk (14) and keep mechanical vibration resonant frequencies higher than the disk rotational frequency.
    Type: Grant
    Filed: September 18, 1992
    Date of Patent: October 25, 1994
    Inventor: Thomas P. Riederer
  • Patent number: 5345348
    Abstract: In an apparatus for controlling a moving speed of a magnetic head, servo data previously recorded on a recording medium is read out during the movement of the magnetic head. A moving speed value of the magnetic head is computed on the basis of position data (representing the current position of the magnetic head) produced from the read out servo data, and a target speed value corresponding to a distance between the current position of the magnetic head and target track position is computed. The moving speed value is subtracted from the target speed value to obtain a differential speed value. The speed of the magnetic head is thus controlled in accordance with whether the differential speed value is positive or negative. Further, a target speed value corresponding to the elapsed time from the start of the movement of the magnetic head is computed, and the moving speed value is subtracted from the target speed value to obtain a differential speed value.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: September 6, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hiroshi Suzuki
  • Patent number: 5343341
    Abstract: A method for seeking the center of a data track recorded on a magnetic tape using a read head, having an accuracy which is not limited by the stepper mechanism which positions the read head relative to the tape, makes use of the discovery that the fundamental component of tape wander is independent of the tape cartridge vendor and the tape length, and therefore the tape wander can be averaged over an integral number of tape wander periods. In the method, the average output from a read head over an integral number of tape wander periods is found at the lower and upper edges of a data track. The read head output from the center of the track is then measured, and is used to calculate an output change versus head position when the read head is partially in the track.
    Type: Grant
    Filed: October 15, 1992
    Date of Patent: August 30, 1994
    Assignee: Tandberg Data A/S
    Inventor: Rolf Jahren
  • Patent number: 5341255
    Abstract: A computer disc drive includes a disc with circumferentially arranged tracks, a number of sectors on each track, with each sector including positional and data fields. The disc drive also includes a servo system with a magnetic head, arm, motor, and servo signal processor. One track of the disc drive includes a number of sectors, with each of the sectors including a positional field. A second track of the disc drive includes a number of sectors, with each of the sectors including a positional field. The positional fields of the second track are in a phase variant relationship, or staggered configuration, with the positional fields of the first track. Thus, the magnetic head reading from the first track or the second track is assured of producing a coherent signal with positional information that is sufficient for the servo system to process, despite interfering magnetic patterns between the two tracks.
    Type: Grant
    Filed: October 12, 1993
    Date of Patent: August 23, 1994
    Assignee: Seagate Technology, Inc.
    Inventors: James A. Starr, Norman R. Sneddon