Browse Prior Art Database

Head Positions by Proximity Detection of Disk Edge

IP.com Disclosure Number: IPCOM000079838D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Baldwin, JM: AUTHOR [+3]

Abstract

Head position detection can be made insensitive to head-to-track misalignment caused by disk expansion due to temperature changes, and track mislocation due to spindle and disk pack eccentricity, tilt, runout, wear, and low-frequency vibration by this system.

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Head Positions by Proximity Detection of Disk Edge

Head position detection can be made insensitive to head-to-track misalignment caused by disk expansion due to temperature changes, and track mislocation due to spindle and disk pack eccentricity, tilt, runout, wear, and low- frequency vibration by this system.

A head 3 and a proximity detection device 5 is mounted on a movable mechanism 2 carrying a servo actuator 1. The proximitor 5 is positioned so as to monitor the position of the outer edge of the disk 4. The head 3 is positioned over the recording media.

Data track position is defined by a signal level of the proximitor 5, which corresponds to a dimension between the outer edge of the disk 4 and the proximitor 5. Any one of several data tracks can be selected by comparing the signal output from the proximitor to that of a reference signal, which corresponds to the desired track location. When the reference and proximitor signal levels are different, an error signal is generated and fed into the servo actuator 1 which moves the head 3 and proximitor 5 until the error is zero. The zero-error condition corresponds to an "on track" condition.

Dimensional changes can occur between the head read/write element 3 and the data track on the disk 4, due to thermal expansion of the disk or eccentricity, tilt, runout, wear or vibration of the spindle or disk pack. Because the data tracks are concentric to the outer edge of the disk 4, any change in the track location is ...