IP Library Granted Patent US 8,520,333
Granted Patent B2
US 8,520,333 · App. 13/084,012 · Granted Aug 27, 2013

Magnetic structure for erasing disk or disks within hard disk drives

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Quick Facts
Patent No.
US 8,520,333
App. No.
13/084,012
Granted
Aug 27, 2013
Kind
B2
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.

Claims (14)

1. A structure for erasure of magnetic media in a hard drive, comprising:

a main field pole magnet polarized in a direction toward a drive spindle motor in the hard drive;

at least two quadrature magnets disposed adjacent the main field pole magnet and polarized in a direction toward the main field pole magnet, the main pole magnet and the at least two quadrature magnets shaped to provide a slot for insertion of the magnetic media; and

at least two inverse polarity magnets disposed on portions of the main field pole and quadrature magnets forming the slot, the inverse polarity magnets polarized in a direction opposed to the direction of the main field pole magnet.

2. The structure of claim 1 further comprising a pole piece disposed on a surface of each inverse magnet directed toward the hard drive.

3. The structure of claim 2 wherein the pole pieces comprise soft iron.

4. The structure of claim 2 further comprising two bucking magnets polarized in the direction of main field pole magnet and positioned in front of the pole pieces.

5. A structure for erasure of magnetic media in a hard drive, comprising:

a main field pole magnet polarized in a direction toward a drive spindle motor in the hard drive;

at least two quadrature magnets disposed adjacent the main field pole magnet and polarized in a direction toward the main field pole magnet, the main pole magnet and the at least two quadrature magnets shaped to provide a slot for insertion of the magnetic media;

at least two inverse polarity magnets disposed on portions of the main field pole and quadrature magnets forming the slot, the inverse polarity magnets polarized in a direction opposed to the direction of the main field pole magnet;

a pole piece disposed on a surface of each inverse magnet directed toward the hard drive; and

two bucking magnets polarized in the direction of main field pole magnet and positioned in front of the pole pieces.

6. The structure of claim 5 wherein the pole pieces comprise soft iron.

Assignments (5)
RELEASE OF SECURITY INTEREST Recorded Jul 29, 2022
From: CITIZENS BANK, N.A.
To: GROTH CORPORATION, LLC (F/K/A GROTH CORPORATION); DEXTER MAGNETIC TECHNOLOGIES, INC.; CONTINENTAL DISC CORPORATION, LLC (F/K/A CONTINENTAL DISC CORPORATION)
Reel/Frame 060668/0268 →
SECURITY INTEREST Recorded Jul 29, 2022
From: DEXTER MAGNETIC TECHNOLOGIES, LLC
To: CITIZENS BANK, N.A.
Reel/Frame 060676/0289 →
SECURITY INTEREST Recorded Jan 8, 2021
From: ADVANTEK, LLC; CONTINENTAL DISC, LLC; DEXTER MAGNETIC TECHNOLOGIES, INC.; GROTH, LLC
To: CITIZENS BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 054861/0118 →
SECURITY INTEREST Recorded Mar 6, 2015
From: DEXTER MAGNETIC TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 035100/0912 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 11, 2011
From: LI, CHUN
To: DEXTER MAGNETIC TECHNOLOGIES, INC.
Reel/Frame 026105/0656 →