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:
Apr. 12, 1994
Filed:
Mar. 10, 1992
Michael R Hatch, Palo Alto, CA (US);
Ronald R Moon, Los Gatos, CA (US);
Robert P Cloutier, Campbell, CA (US);
NEC Corporation, Tokyo, JP;
Abstract
When a rotary-actuator voice coil type disk drive is powered down the actuator arm is moved to a parking position against an I.D. stop by a disk spindle motor back EMF, resulting from the spinning down of the spindle motor. Current is applied by the back EMF through a delay circuit to a latch arm voice coil on one end of a latch arm and forming part of a magnetic circuit including a drive permanent magnet on a ferrous base plate and a ferrous upper plate. Resultant movement of the latch arm overcomes a spring bias of a torsion spring extending between the base plate and pivoted latch arm normally keeping the latch arm in an unlatched position. A latch permanent magnet extends from the other end of the latch arm and is brought into spaced proximity, but not contact, with a ferrous member extending from the actuator arm so that the magnetic force therebetween holds the actuator arm against the I.D. stop in latched position to withstand high shock loadings. Powering the rotary actuator voice coil motor up overcomes the magnetic force and allows the biased torsion spring to move the latch arm to the unlatched position without resultant loss of data storage area.