Chun M Li

US Patent:

8305177, Nov 6, 2012

Filed:

Jan 5, 2010

Appl. No.:

12/652621

Inventors:

Chun Li - Plainview NY, US
David Choit - Dix Hills NY, US

Assignee:

Dexter Magnetic Technologies, Inc. - Elk Grove Village IL

International Classification:

H01F 7/02

US Classification:

335306

Abstract:

A magnet assembly for decoupling a plurality of different types of magnetically operated security devices includes a center pole magnet having a magnetic orientation along a first direction. A plurality of magnets adjacent to and surrounding the center pole magnet define an opening above the center pole magnet. Each adjacent magnet has a magnetic orientation orthogonal to the first direction. An end pole magnet is disposed adjacent to one of the magnets adjacent to the center pole magnet. The end pole magnet has magnetic orientation opposed to the first direction.

US Patent:

8520333, Aug 27, 2013

Filed:

Apr 11, 2011

Appl. No.:

13/084012

Inventors:

Chun Li - Plainview NY, US

Assignee:

Dexter Magnetic Technologies, Inc. - Elk Grove Village IL

International Classification:

G11B 5/03
H01F 13/00

US Classification:

360 66, 361149

Abstract:

A structure for erasure of magnetic media in a hard drive includes a main field pole magnet polarized in a direction toward a drive spindle motor in the hard drive. At least two quadrature magnets are disposed adjacent the main field pole magnet and polarized in a direction toward the main field pole magnet. The main field pole magnet and the at least two quadrature magnets are shaped to provide a slot for insertion of the magnetic media. At least two inverse polarity magnets are disposed on portions of the main pole and quadrature magnets forming the slot. The inverse polarity magnets are polarized in a direction opposed to the direction of the main field pole magnet.