David C Harper

US Patent:

6934108, Aug 23, 2005

Filed:

Jan 22, 2003

Appl. No.:

10/349307

Inventors:

David H. Harper - San Jose CA, US
Mark A. Taylor - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B015/18

US Classification:

360 71

Abstract:

A system and method of controlling tape tension during operation of a tape drive by making use of pre-existing timing based servo patterns formatted on the media. Changes in servo pattern timing are read at regular intervals and used to calculate changes in tension, with the torque of the tape reel motors being adjusted accordingly.

US Patent:

7092196, Aug 15, 2006

Filed:

Jun 23, 2004

Appl. No.:

10/876197

Inventors:

James H. Eaton - Morgan Hill CA, US
Darrell G. Follett - San Jose CA, US
David H. Harper - San Jose CA, US
Wayne I. Imaino - San Jose CA, US
Leif S. Kirschenbaum - San Francisco CA, US
Andrew J. McKee - San Jose CA, US
Luis H. Palacios - Mountain View CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/02
G11B 9/00
G01B 7/00
G11B 21/04

US Classification:

360 75, 32420716

Abstract:

A system and method for analyzing a coil actuator of a type having a coil and a magnet. A current source selectively applies a first current to a coil of a coil actuator for setting a moveable part of the coil actuator to a first position. A recording system captures data corresponding to a back electromotive force voltage produced by oscillation of the coil actuator upon movement of the moveable part of the coil actuator to a second position. A processor applies a curve fit to the back electromotive force data for calculating a frequency characteristic and damping response of the coil actuator.

US Patent:

7414812, Aug 19, 2008

Filed:

Sep 2, 2005

Appl. No.:

11/218793

Inventors:

David Harper - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/55

US Classification:

3602611

Abstract:

An actuator assembly includes a first housing portion and a second housing portion coupled to the first housing portion, which together define a housing having an interior. A beam, preferably of one-piece construction, extends from the interior of the housing to the exterior of the housing. A coil, pole piece, and magnet are positioned in the interior of the housing. Energizing the coil causes movement of the beam relative to the housing. The housing portions may be identical. The housing portions may be symmetrical about their edges of coupling.

US Patent:

7538980, May 26, 2009

Filed:

Sep 14, 2005

Appl. No.:

11/227350

Inventors:

David Harper - San Jose CA, US
Wayne I. Imaino - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/55

US Classification:

3602611

Abstract:

An actuator assembly according to one embodiment includes an inner effective annular magnet polarized radially, an outer effective annular magnet polarized radially, and a coil positioned between the inner and outer magnet structures. The magnet structures may be continuous magnets or constructed of multiple magnets. The coil may be a dual wound monofilament coil, where sections of the filament are wound in opposite directions.

US Patent:

7660076, Feb 9, 2010

Filed:

Sep 2, 2005

Appl. No.:

11/218704

Inventors:

David Harper - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/55

US Classification:

3602613, 74 89

Abstract:

An actuator includes a leadscrew and a helical gear engaging the leadscrew, the helical gear having journals extending from opposite ends thereof. A carriage operatively engages the journals. A relative rotation between the leadscrew and the helical gear creates a relative movement between the carriage and the leadscrew in a direction parallel to an axis of the leadscrew.

US Patent:

7845067, Dec 7, 2010

Filed:

Jul 8, 2008

Appl. No.:

12/169426

Inventors:

David Harper - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/127
H04R 31/00

US Classification:

2960303, 2960304, 2960306, 2960307, 3602355, 3602445, 3602358

Abstract:

A method for assembling an actuator assembly includes providing a first housing portion and a second housing portion; providing a coil, a pole piece, a magnet, and a completed beam; positioning the coil, pole piece, magnet, and completed beam between the housing portions; and coupling the housing portions together.

US Patent:

20030128476, Jul 10, 2003

Filed:

Jan 7, 2002

Appl. No.:

10/041864

Inventors:

William Dyer - San Jose CA, US
James Eaton - Morgan Hill CA, US
David Harper - San Jose CA, US

International Classification:

G11B005/55

US Classification:

360/261100

Abstract:

A mechanical linkage, including a worm gear and a worm gear support bracket, for joining a drive motor to a helical gear; it is particularly adapted for controlling a tape drive head. The worm gear head is threadably engaged with the helical gear. The shaft of the worm gear is engaged with the motor and is sufficiently flexible to operably correct misalignments between the worm gear shaft and the motor shaft. The support bracket includes a flat leaf spring which provides lateral spring force against the worm gear shaft to maintain a driving engagement between the worm gear and the helical gear, while the leaf spring is stiff in the in-plane directions of movement. The support bracket also includes a bushing, such as a C-shaped bushing or a cylindrical bushing, which provides support for the worm gear shaft against the helical gear.

US Patent:

20060096399, May 11, 2006

Filed:

Nov 10, 2004

Appl. No.:

10/985436

Inventors:

David Harper - San Jose CA, US
Luis Borja - Mountain View CA, US

International Classification:

F16H 1/24

US Classification:

074424710

Abstract:

An actuator according includes a threaded shaft and a carriage having a shaft engaging portion coupled to the threaded shaft. The carriage is moveable in a direction parallel to an axis of the threaded shaft upon a relative rotation between the threaded shaft and the shaft engaging portion. A ceramic bushing is coupled to the shaft engaging portion of the carriage, the bushing surrounding the threaded shaft. The ceramic bushing is much harder than heretofore used materials and results in greatly reduced particulate formation. The carriage or portion thereof can be formed around the bushing, e.g., by injection molding.