Method of manufacturing a multitrack magnetic head

• US 3,909,932 A
• Filed: 07/22/1974
• Issued: 10/07/1975
• Est. Priority Date: 10/23/1973
• Status: Expired due to Term

• Current Assignee: William L. Kroon
• Original Assignee: William L. Kroon
• Inventors: Kroon, William L.
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US05/490,309
• Time in Patent Office: 442 Days
• Field of Search: 29/603 346/74ML 360/121,127
• US Class Current: 29/603.21
• CPC Class Codes: G11B 5/29 Structure or manufacture of unitary devices formed of plural heads for more than one track G11B5/33, G11B5/49 and subgroups take precedence; in thin film structure G11B5/31
• CPC Class Codes: G11B 5/295 Manufacture
• CPC Class Codes: Y10T 29/49057 Using glass bonding material
• CPC Class Codes: Y10T 29/49059 with work positioning means

Abstract

A multitrack magnetic head asembly is described in which magnetic ferrite pole tips are held in place at the transducing face of the assembly by a ceramic material to which the ferrite pole pieces are glass bonded. This face part is in turn secured to a core housing carrying a plurality of core members and coil means disposed to complete the magnetic circuit through the ferrite pole pieces. As magnetic ferrite materials have many characteristics similar to the ceramic material, the face part composed of these two substances becomes a structure of high physical integrity capable of lasting under the abusive conditions of high magnetic tape speeds. Also, a method of constructing this head assembly is provided in which the ceramic face part is comprised of two half portions each carrying a set of ferrite pole pieces glass bonded therein such that the ceramic half portions can be assembled with a layer of nonmagnetic material disposed therebetween to form the transducing gaps between each associated pair of ferrite pole pieces. Once the face part portions are assembled and secured, this sub-assembly is mounted on the core housing, also of ceramic material, in such a way that the core members are arranged in the core housing to engage the ferrite pole pieces.

Claims

1. A METHOD OF CONSTRUCTING A MAGNETIC HEAD ASSEMBLY COMPRSING THE STEPS OF, FORMING A PLURALITY OF SLOTS IN A BLOCK OF CERAMIC MATERIAL, GLASS BONDING A PLURALITY OF PIECES OF MAGNETIC FERRITE MATERIAL IN SAID SLOTS, CUTTING SAID BLOCK ALONG A PLANE INTERCEPTING SAID FERRITE PIECES TO FORM AT LEAST TWO SEVERED BLOCK PORTIONS EACH CARRYING PORTIONS OF SAID FERRITE PIECES, SECURING SAID BLOCK PORTIONS TOGETHER TO FORM A FACE PART FOR SAID HEAD ASSEMBLY WITH RESPECTIVE ONES OF SAID FERRITE PIECES OF EACH BLOCK PORTION ALIGNED AND A LAYER OF NONMAGNETIC GAP FORMING MATERIAL DISPOSED THEREBETWEEN SUCH THAT A FACE PART HAVING APLURALITY OF SPACED MAGNETIC HEA POLE TIPS IS FORMED, AND MOUNTING SAID FACE PART ONTO A CORE HOUSING CARRYING A PLURALITY OF CORE MEMBERS AND COIL MEANS WITH SAID CORE MEMBERS EACH ARRANGED TO ENGAGE ASSOCIATED FERRITE PIECES OF SAID FACE PART TO COMPLETE MAGNETIC CIRCUITS TRAVERSING THE NONMAGNETIC GAPS THEREBETWEEN.

2. The method of claim 1 wherein said block is generally rectangular and said slots are parallel across one of the planar faces thereof and said cutting plane extends normal to said planar face and normal to said slots, the further steps comprising, forming a bevel along one edge of each of said block portions together with said planar faces, said bevelled edges defining a V-shaped groove, the face part formed by said secured block portions being mounted with said V-shaped groove confronting said core housing and said core members having spaced apart pole portions engaging said ferrite pieces on opposite sides of said groove.

3. The method defined in claim 2 further comprising the steps of, disposing a wedge shaped ceramic member in mated engagement and recessed within the V-shaped groove of said face part, bonding said wedge member to said ceramic block portions and ferrite pieces prior to mounting on said core housing, and securing said block portions to said core housing by applying epoxy adhesive in a window space formed between said recessed V-shaped groove and said core housing.

4. The method as defined in claim 2 further comprising the steps of, forming a tie-bar slot at each end of said block parallel to said ferrite pieces prior to cutting said block into said severed portions, and with said block portions arranged in assembled relation disposing and bonding a tie-bar of ceramic or ferrite material in each said tie-bar slot to bridge and secure said block portions together as said face part.

5. The method of claim 1 further defined by selecting said ceramic material and ferrite material and the material for forming said glass bond to have coefficients of thermal expansion within the same range.

6. The method of claim 1 further defined by said nonmagnetic material layer provided by a particle sputtering process.

7. The method of claim 1, further defined by said core housing being formed of a ceramic material and said core members being formed of a magnetic ferrite material and comprising the further steps of, mounting said core members in said ceramic core housing, epoxying said core members in place and curing, lapping the surface of said core housing and exposed pole portions of said core members for receiving said face part, and lapping the mating surface of said face part before mounting onto said core housing.

8. The method of claim 7, further comprising the steps of mounting a plurality of shield parts in said face part by forming a shield part slot between each pair of adjacent ferrite pieces bonded in said block and mounting and bonding a shield part of magnetic ferrite material in each set of registering shield part slots when said block portions are in assembled relation, mounting a plurality of intercore magnetic shields along with and in between said core members in said housing, said shield parts carried by said face part arranged to engage corresponding shields carried by said core housing when said face part is mounted on and secured to the core housing.

9. A method of constructing a magnetic head assembly comprising the steps of, forming at least two block portions of ceramic material each having a plurality of slots carrying a coRresponding plurality of pieces of magnetic ferrite material glass bonded therein, forming a planar surface on each block portion with portions of said ferrite pieces flush therewith, securing said block portions together to form a face part for said head assembly with said planar surface portions confronting and respective ones of said ferrite pieces of each block portion aligned and with a gap forming nonmagnetic material therebetween such that a face part having a plurality of spaced magnetic head pole tips is formed, mounting said face part onto a core housing carrying a plurality of core members and coil means with each core member arranged to engage associated ferrite pieces to complete a magnetic circuit traversing the nonmagnetic gap therebetween, contouring said face part such that said ferrite pieces and nonmagnetic gaps therebetween are exposed for transducing with respect to a magnetic storage medium.