Browse Prior Art Database

Thermally Activated Micropositioner

IP.com Disclosure Number: IPCOM000042053D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Cooper, ES: AUTHOR

Abstract

In magnetic disk files, a magnetic transducer-positioning system functions to position the read/write magnetic transducers over the center of a data track. Generally, such systems employ a closed-loop servo system that includes a servo transducer cooperating with prerecorded servo tracks on one disk surface. The positioning system includes a carriage assembly which moves the servo transducer and one or more data transducers conjointly. When the servo transducer is caused to follow a servo track, the read/write transducers follow their corresponding data tracks on other surfaces. As track densities increase above the range of 1500 to 2000 tracks per inch, temperature changes within the file tend to cause the servo transducer to be offset from the read/write transducers.

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Thermally Activated Micropositioner

In magnetic disk files, a magnetic transducer-positioning system functions to position the read/write magnetic transducers over the center of a data track. Generally, such systems employ a closed-loop servo system that includes a servo transducer cooperating with prerecorded servo tracks on one disk surface. The positioning system includes a carriage assembly which moves the servo transducer and one or more data transducers conjointly. When the servo transducer is caused to follow a servo track, the read/write transducers follow their corresponding data tracks on other surfaces. As track densities increase above the range of 1500 to 2000 tracks per inch, temperature changes within the file tend to cause the servo transducer to be offset from the read/write transducers. As a result, the data track that was written at one temperature may not be read accurately at a different temperature. The arrangement shown in the figure provides each head-arm member 10 of the head-arm assembly with a thermal micropositioner 11. As shown in the figure, the micropositioner includes a heating element 12 firmly attached to the head-arm member 10 which is fixed at end 10A. Element 12 is provided with a pair of conductors 13 and 14 which supply current to element 12 to raise the temperature of the member 10 and cause member 10 to increase in length a known amount. By suitably controlling the current supplied to each micropositioner, the relative pos...