Crosstalk shielding assembly for addition to one head of a dual magnetic head assembly

• US 4,636,902 A
• Filed: 07/09/1984
• Issued: 01/13/1987
• Est. Priority Date: 07/09/1984
• Status: Expired due to Fees

• Current Assignee: Microtek Storage Corporation
• Original Assignee: Microtek Storage Corporation
• Inventors: Johnston, James, Lee, John S., Flanigan, Charles, Dalziel, Warren L., Daniels, Donald V.
• Primary Examiner(s): Tupper, Robert S.
• Application Number:
  US06/629,122
• Time in Patent Office: 918 Days
• Field of Search: 360/128, 360/129, 360/122
• US Class Current: 360/128
• CPC Class Codes: G11B 5/11 Shielding of head against electric or magnetic fields
• CPC Class Codes: G11B 5/4893 relative to moving tape

Abstract

A dual magnetic head assembly is provided with asymmetrical crosstalk shielding. One of the heads includes a pair of mu-metal washers sandwiching a copper washer, the stacked washers surrounding the portion of the head including the read-write gap. The washers are enclosed within a copper plated mu-metal cap having a central opening through which the gap-containing portion of the head projects for cooperation with a magnetic medium. The other head is unshielded.

Claims

1. An apparatus for effecting data recording and reproducing in relation to a movable magnetic medium, the apparatus including:

a pair of identical, magnetic read/write head assemblies, each assembly including means defining a read/write gap;

means for supporting the head assemblies in spaced-apart relationship along the direction of motion of the magnetic medium; and

magnetic shielding mounted on one of the heads, said shielding circumscribing the gap-defining means and including a substantially non-magnetic, electrically conductive shield element sandwiched between a pair of high magnetic permeability elements;

the electrically conductive shield element being copper and the high magnetic permeability elements being made of mu-metal, the shield elements being stacked washers with their holes aligned and through which holes the gap-defining means projects for data transfer relationship with said magnetic medium.

2. An apparatus, as defined in claim 1, in which:

the head assembly is of generally cylindrical configuration having an apex portion including the gap-defining means and a generally annular relieved portion surrounding the apex, said washer shield elements being mounted in said annular relieved portion;

and which includes;

a generally cylindrical, copper plated, mu-metal cap housing said shield elements, said cap including a central aperture in alignment with the holes in the shield elements.

3. A shielded magnetic read/write head assembly for use with a magnetic medium, the assembly comprising:

a magnetic head having an outer, generally cylindrical surface, an apex including means defining a read/write gap, and a generally concave, annular surface receding from the apex and joining the apex and the outer surface;

a series of shield elements stacked within the confines of the concave surface, the elements including a pair of mu-metal washers sandwiching a copper washer; and

a copper plated mu-metal cap enclosing the shield elements, the cap having a front face defining a central opening in alignment with the openings in the washer shield elements, the apex of the head projecting through the central opening in the cap for cooperation with the magnetic medium.

4. Apparatus, as defined in claim 3, in which:

the head assembly includes a second magnetic head substantially identical to and disposed adjacent the first-mentioned magnetic head.

5. A crosstalk shielding assembly for addition to a read/write magnetic head comprising the combination of:

a stack of washers of like size and of different material composition;

a cap of generally cylindrical configuration and having an annular face at one side thereof, the stack of washers being generally concentrically disposed within and against the annular face of the cap; and

the stack of washers being comprised of a first washer of substantially non-magnetic, electrically conductive material sandwiched between second and third washers of high magnetic permeability material, and the cap being of relatively high magnetic permeability material.

6. Apparatus, as defined in claim 5, in which:

the first washer is made of copper, the second and third washers are made of mu-metal, and the cap is made of copper plated mu-metal.

7. An apparatus for effecting data recording and reproducing in relation to a moveable magnetic medium, the apparatus including:

a pair of substantially identical magnetic read/write head assemblies, each of the head assemblies having a read/write gap at an apex thereof;

means for supporting the head assemblies in spaced-apart relation along the direction of motion of the magnetic medium;

a crosstalk shielding assembly mounted on one of the head assemblies and including a stack of ring-shaped elements disposed against the head assembly so as to encircle the read/write gap in the region of the apex, and a cap member of generally cylindrical configuration mounted on the head assembly and containing the stack of ring-shaped elements therein; and

the stack of ring-shaped elements being comprised of a first washer of substantially non-magnetic, electrically conductive material sandwiched between second and third washers of high magnetic permeability material, and the cap member being of relatively high magnetic permeability material.

8. Apparatus, as defined in claim 7, in which:

the first washer is made of copper, the second and third washers are made of mu-metal, and the cap member is made of copper plated mu-metal.

9. Apparatus, as defined in claim 7, in which:

each of the pair of substantially identical magnetic read/write head assemblies is a floppy disk drive head assembly having a button-like apex.