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US3922776A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for making narrow track ferrite core flying pads

Assignee: Vrc California Inc
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Filing: 1974-05-13
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Granted: 1975-12-02
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Expires: 1994-05-13
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Abstract

Abstract A high yield method for manufacturing a narrow precisely defined track width ferrite core flying pad in which a core is bonded to a support piece after which a portion of the core adjacent an air bearing surface of the support piece is removed, thereby narrowing the core width. The ferrite core having a glass filling narrowing to an apex toward the air bearing surface is lapped proximate to the apex to define an efficient gap depth. Grooving the air bearing surface adjacent the core provides a lapping tool approach region. The frontal portion of the core is lapped perpendicular to the frontal surface and within the groove providing a narrowed track width. Bonding a glass bead against a ridge formed by narrowing of the core provides protective support therefor. The groove is reground to define air bearing characteristics. Precision contouring provides a magnetic medium protective surface.

Inventors

  • 👤 James A Alger
  • 👤 John J Miyata

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 06:55
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B5/127; G11B5/1272; G11B5/187; G11B5/1871; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49027; Y10T29/4903; Y10T29/49032; Y10T29/49036; Y10T29/49041; Y10T29/49048

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 173 words
A HIGH YIELD METHOD FOR MANUFACTURING A NARROW TRACK WIDTH FLYING PAD OF THE TYPE COMPRISING A FERRITE CORE HAVING A FRONTAL PORTION OF SMALLER WIDTH THEN A REAWARD PORTION, THE CORE BEING CERAMICALLY BONDED TO A SUPPORT PIECE, AND THE COMBINED CORE AND SUPPORT PIECE HAVING A FINISHED SURFACE FOR PROTECTIVELY APPROACHING A MOVING MAGNETIC RECORD SURFACE, COMPRISING THE STEPS OF: FORMING A GROOVE ADJACENT TO A CORE RECEIVING OPENING IN A SUPPORT PIECE OF RPROVIDING A MACHINING TOOL APPROACH REGION BONDING A GENERALLY PLANAR FERRITE CORE SUBSTANTIALLY PERPENDICULAR TO A FRONTAL SURFACE OF THE SUPPORT PIECE; REMOVING A PORTION OF THE FERRITE GENERALLY PARALLEL TO THE PLANE OF THE CORE AND AT AN END OF THE CORE ADJACENT THE FRONTAL SURFACE TO FOEM AN EFFECTIVELY NARROW TRACK POLE PIECE; LAPPING THE CORE GENERALLY PARALLEL TO THE FRONTAL SURFACE TO DEFINE A DESIRED GAS DEPTH; FINISHING THE GROOVE TO DEFIN AN AIR-BEARING FLOAT LEVEL; AND, CONTOURING THE FRONTAL SURFACE OF THE SUPPORT PIECE TO PROVIDE A MAGNETIC MEDIUM PROTECTIVE AIR BEARING SURFACE.
Claim 2
Dependent Claim 173 words
A HIGH YIELD METHOD FOR MANUFACTURING A NARROW TRACK WIDTH FLYING PAD OF THE TYPE COMPRISING A FERRITE CORE HAVING A FRONTAL PORTION OF SMALLER WIDTH THEN A REAWARD PORTION, THE CORE BEING CERAMICALLY BONDED TO A SUPPORT PIECE, AND THE COMBINED CORE AND SUPPORT PIECE HAVING A FINISHED SURFACE FOR PROTECTIVELY APPROACHING A MOVING MAGNETIC RECORD SURFACE, COMPRISING THE STEPS OF: FORMING A GROOVE ADJACENT TO A CORE RECEIVING OPENING IN A SUPPORT PIECE OF RPROVIDING A MACHINING TOOL APPROACH REGION BONDING A GENERALLY PLANAR FERRITE CORE SUBSTANTIALLY PERPENDICULAR TO A FRONTAL SURFACE OF THE SUPPORT PIECE; REMOVING A PORTION OF THE FERRITE GENERALLY PARALLEL TO THE PLANE OF THE CORE AND AT AN END OF THE CORE ADJACENT THE FRONTAL SURFACE TO FOEM AN EFFECTIVELY NARROW TRACK POLE PIECE; LAPPING THE CORE GENERALLY PARALLEL TO THE FRONTAL SURFACE TO DEFINE A DESIRED GAS DEPTH; FINISHING THE GROOVE TO DEFIN AN AIR-BEARING FLOAT LEVEL; AND, CONTOURING THE FRONTAL SURFACE OF THE SUPPORT PIECE TO PROVIDE A MAGNETIC MEDIUM PROTECTIVE AIR BEARING SURFACE.
Claim 3
Dependent Claim 56 words
The invention as set forth in claim 1, and further comprising the steps of: bonding a bead along a ridge, formed by the removing step of narrowing the core, for supporting the narrowed frontal portion; and, lapping the bead supported frontal portion to make the beaded core flush with the frontal surface of the support piece.
Claim 4
Dependent Claim 75 words
The invention as set forth in claim 2, and in which the step of making a groove comprises the steps of grinding an initial groove in the support piece prior to the step of bonding the core to the support piece and grinding glass in the groove prior to the removing step of narrowing the core to remove excess material in the groove resulting from the step of bonding the core to the support piece.
Claim 5
Dependent Claim 110 words
The invention as set forth in claim 3, and in which the support piece comprises a shoe element glass bonded to a shield and the flying pad is formed by bonding the core to the support piece, comprising the steps of disposing at least one glass element on the frontal surface of the support piece along the core, the glass element having a melting temperature less than a melting temperature of a glass bond between the shoe and the shield and heating the assembly thereby obtained beyond the melting temperature of the glass element and less than the melting temperature of the glass bond between the shoe and the shield.
Claim 6
Dependent Claim 237 words
A high yield method for manufacturing a flying pad having a track width on the order of 0.001 inch, of the type comprising a ferrite core having a frontal portion of smaller width than a rearward portion and a combined core and support piece having a finished surface for protectively approaching a moving magnetic record surface, comprising the steps of: grooving a support piece to a depth on the order of 0.005 inches to providing a cutting tool access region; fixturing a ferrite core within an elongated opening of the support piece; thermally bonding with glass the ferrite core to the support piece; lapping the core parallel to a frontal surface of the support piece to a control gap depth; grinding the groove to remove glass; narrowing the frontal portion of the core to a final track width of the order 0.001 inch subsequent to the thermal bonding step to define a narrow track width; positioning a glass rod on an exposed ridge of the narrowed core; bonding the rod to the ridge to provide support for the narrowed core; grinding the groove to a final dimension and removing excess glass from the groove resulting from the last mentioned bonding step; lapping the support piece to remove glass and to define a final gap depth; and, contour lapping the support piece to a radius on the order of 270 inches to provide a magnetic surface protective finish.
Claim 7
Dependent Claim 237 words
A high yield method for manufacturing a flying pad having a track width on the order of 0.001 inch, of the type comprising a ferrite core having a frontal portion of smaller width than a rearward portion and a combined core and support piece having a finished surface for protectively approaching a moving magnetic record surface, comprising the steps of: grooving a support piece to a depth on the order of 0.005 inches to providing a cutting tool access region; fixturing a ferrite core within an elongated opening of the support piece; thermally bonding with glass the ferrite core to the support piece; lapping the core parallel to a frontal surface of the support piece to a control gap depth; grinding the groove to remove glass; narrowing the frontal portion of the core to a final track width of the order 0.001 inch subsequent to the thermal bonding step to define a narrow track width; positioning a glass rod on an exposed ridge of the narrowed core; bonding the rod to the ridge to provide support for the narrowed core; grinding the groove to a final dimension and removing excess glass from the groove resulting from the last mentioned bonding step; lapping the support piece to remove glass and to define a final gap depth; and, contour lapping the support piece to a radius on the order of 270 inches to provide a magnetic surface protective finish.
Claim 8
Dependent Claim 106 words
The invention as set forth in claim 5 and in which the step of fixturing the core comprises the steps of disposing the core in the elongated opening of the support piece generally perpendicular to a frontal surface of the support piece, allowing clearance between the core and walls defining the elongated opening so that glass may flow between the surfaces of the cores and the walls, and disposing on the frontal surface of the support piece a pair of glass rods on the order of 0.025 inch diameter and on the order of twice the core width along and adjacent opposite widths of the core.
Claim 9
Dependent Claim 32 words
The invention as set forth in claim 5 and which the steps of narrowing the frontal portion of the core comprises the step of disposing a diamond cutting tool within the groove.
Claim 10
Dependent Claim 77 words
The invention as set forth in claim 5 in which the ferrite core has dimensions of the order of 0.12 inch length by 0.06 inch width by 0.004 inch thickness and in which the step of narrowing the core comprises the step of removing a thickness adjacent the frontal portioN of the core on the order of 0.003 inch to provide a core thickness adjacent to the frontal portion of about 0.001 inch along the core width.

References Cited (Backward Citations)

US3384954A Cited
US3577634A Cited
US3735052A Cited
US3789505A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-12-01 1979-06-02 1979-12-02 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-12-01 1983-06-02 1983-12-02 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-12-01 1987-06-02 1987-12-02 $7700.00 Window Closed / Lapsed

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