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:
Nov. 04, 2003
Filed:
Mar. 10, 2000
Hidetoshi Kawachi, Nishitama-gun, JP;
Kabushiki Kaisha Toshiba, , JP;
Abstract
In a magnetic disk drive, in the case of unloading a head, a carriage receives a driving force of a voice coil motor as a controlled object so as to drive the head, and then, a speed &ohgr; of the carriage is detected from a back electromotive voltage generated in a coil of the voice coil motor. A ramp collision discriminator makes a decision that the head collides with the ramp on the basis of at least one of the speed &ohgr; and a controlled manipulated variable fed back to the voice coil motor as being a controlled object from a speed controller. In the case where a ramp collision is discriminated, a gain changeover switch is controlled so that a speed feedback gain of the speed controller is changed into a high gain side. Therefore, when the head collides with the ramp, it is possible to prevent a great reduction of the carriage moving speed and a temporary stop of a carriage moving operation, and thus, to realize a stable head unload operation.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile