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Shield for Protecting Magnetic Head from Ambient AC and DC Magnetic Fields

IP.com Disclosure Number: IPCOM000084672D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Castrodale, DO: AUTHOR [+3]

Abstract

Shields 10 and 12 of low-reluctance material each extends partially around magnetic transducers 14 and 16 and are disposed opposite each other, so that together they provide nearly 360 degrees protection from ambient AC and DC magnetic fields for the transducers 14 and 16.

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Shield for Protecting Magnetic Head from Ambient AC and DC Magnetic Fields

Shields 10 and 12 of low-reluctance material each extends partially around magnetic transducers 14 and 16 and are disposed opposite each other, so that together they provide nearly 360 degrees protection from ambient AC and DC magnetic fields for the transducers 14 and 16.

Transducer 14 has erase core legs 14a and 14b, and an erase winding 14c is wound about core leg 14a. Transducer 14 has an open back at 14d and has a narrow gap 14e opposite the back 14d and positioned in close proximity to a magnetic disk 18. Without shielding, and due particularly to the open back 14d, an ambient magnetic field existing perpendicular to erase gap 14e shunts through the erase gap 14e in passing from core leg 14a to core leg 14b.

This field produces a magnetic fringe field m at gap 14e and causes data erasure during crossings of concentric tracks on rotatable magnetic disk 18 disposed in close proximity to gap 14e, as shown in Fig. 4. The magnetic fringe field m occurs particularly because the reluctance path through the gap 14e is shorter than that through the back gap 14d. The transducer 16 is similar to the transducer 14, and the same magnetic fringing occurs with respect to the transducer 16.

Transducers 14 and 16 are carried by swing arms 20 and 22 mounted on leaf springs 24 and 26. The shield 12 is horseshoe shaped and extends through slots 28 and 30 in swing arm 22. Ears 12a and 12b are formed on th...