The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 21, 1992
Filed:
Sep. 15, 1989
Hitachi, Ltd., Tokyo, JP;
Abstract
A disk drive unit is disclosed, which comprises a recording medium having more than two disk-shaped recording faces disposed on each other with an interval; information tracks disposed along the periphery on the more than two recording faces and servo signal fields on the recording faces, in the peripheral direction for different recording faces; more than two heads reading out servo information from the servo signal fields on the more than two recording faces; head moving means for moving the heads in the radial direction of the recording faces, linked with each other; means for obtaining position signals on the recording faces at different points of time for different heads on the basis of the servo signals; means for obtaining information on the relative velocity of the heads to the recording faces from the position signals at different points of time for different recording faces, and control means for effecting the velocity control by means of the head moving means on the basis of the information on the relative velocity.