Patent US3863395A successfully refreshed from Google Patents.
US3863395A
Expired / Lapsed
US
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Apparatus for polishing a spherical surface on a magnetic recording transducer
Assignee: Shugart Associates Inc
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Filing: 1974-02-19
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Granted: 1975-02-04
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Expires: 1994-02-19
Abstract
Abstract Apparatus for polishing a spherical work surface comprising a resilient polishing pad formed on a flat rotatable base and including at least one layer of resilient material sandwiched between a flexible abrasive sheet and the base, a workpiece holder for urging a workpiece against the polishing pad with a uniform pressure while simultaneously rotating the workpiece at a uniform rotational speed, an oscillatory motion generator for causing the holder to move randomly over the surface of the polishing pad, the holder and the oscillatory motion generator. The durometer of the resilient layer, the flexibility of the abrasive sheet and the size of the spherical work surface are all matched so that the abrasive surface uniformly conforms to the shape of the work surface to achieve a substantially uniform polishing thereof.
Inventors
- 👤 David A Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:44
CPC Classifications
B; B24; B24B; B24B11/00
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
152 words
Apparatus for polishing a substantially spherical work surface of a workpiece comprising: means forming a polishing pad including a rotatable base having a flat upper surface, at least one layer of resilient material disposed on said flat surface, and a flexible abrasive sheet overlaying the upper surface of said one layer and forming a resilient abrasive surface; a workpiece holder disposed above said polishing pad for rotating said workpiece while urging said work surface against said abrasive surface with a substantially uniform contact pressure; an oscillatory motion generator for causing said holder to move in random fashion across said abrasive surface; and drive means for supplying driving energy to said polishing pad, said holder and said oscillatory motion generator, whereby polishing of said work surface is accomplished by the conforming engagement of said abrasive surface thereto as said workpiece is rotated and randomly moved across the upper surface of said polishing pad.
Claim 2
Dependent Claim
152 words
Apparatus for polishing a substantially spherical work surface of a workpiece comprising: means forming a polishing pad including a rotatable base having a flat upper surface, at least one layer of resilient material disposed on said flat surface, and a flexible abrasive sheet overlaying the upper surface of said one layer and forming a resilient abrasive surface; a workpiece holder disposed above said polishing pad for rotating said workpiece while urging said work surface against said abrasive surface with a substantially uniform contact pressure; an oscillatory motion generator for causing said holder to move in random fashion across said abrasive surface; and drive means for supplying driving energy to said polishing pad, said holder and said oscillatory motion generator, whereby polishing of said work surface is accomplished by the conforming engagement of said abrasive surface thereto as said workpiece is rotated and randomly moved across the upper surface of said polishing pad.
Claim 3
Dependent Claim
104 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 1 wherein said spherical surface is comprised of materials that have different hardness characteristics, said at least one layer including first and second layers of resilient material, said second layer overlying said first layer and being comprised of a material that is harder than the material comprising said first layer so as to stiffen said at least one layer and reduce the conforming engagement of said abrasive surface with said work surface, thereby to reduce the tendency of said abrasive surface to erode softer portions of said work surface.
Claim 4
Dependent Claim
39 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 2 wherein said first and second layers have substantially constant thicknesses, the thickness of said first layer being substantially thicker than said second layer.
Claim 5
Dependent Claim
51 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 2 wherein said workpiece is a magnetic recording head and wherein said spherical surface includes stainless steel and mu metal materials, said first layer being a material having a hardness characteristic of at least 60 Durometer.
Claim 6
Dependent Claim
32 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 2 wherein said first layer is comprised of urethane, and said second layer is comprised of polyvinylchloride.
Claim 7
Dependent Claim
33 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 5 wherein said urethane is about 0.25 inches thick and wherein said polyvinylchloride is about 0.015 inches thick.
Claim 8
Dependent Claim
37 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 5 and including loading means coupled to said holder for urging said work surface against said abrasive surface with a preselected load.
Claim 9
Dependent Claim
29 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 7 wherein said preselected load is in the range between 1 and 8 pounds.
Claim 10
Dependent Claim
33 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 1 wherein said abrasive sheet is comprised of aluminum oxide having a thickness of at least 3 mils.
Claim 11
Dependent Claim
45 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 1 wherein said one layer comprises a plurality of laminations, the lamination juxtaposed subjacent said abrasive sheet being characterized by a greater hardness characteristic than a lamination disposed farther therefrom.
Claim 12
Dependent Claim
45 words
Apparatus for polishing a substantially spherical work surface of a workpiece as recited in claim 1 wherein said one layer is comprised of a material characterized as having a variable density, the density of said layer decreasing as its separation from said abrasive sheet increases.
Claim 13
Dependent Claim
153 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head, the apparatus including a rotatable base having a flat upper surface, a polishing pad disposed on said flat surface and forming an abrasive upper surface, a workpiece holder disposed above said polishing pad for rotating said workpiece while urging said work surface against said abrasive surface with a substantially uniform contact pressure, an oscillatory motion generator drivingly connected to said holder for moving same randomly across said pad, the improvement comprising: polishing pad means including a first layer of resilient material disposed on said flat surface, and a flexible abrasive sheet overlaying the upper surface of said first layer and forming a resilient abrasive surface, whereby polishing of said spherical surface is accomplished by the conforming engagement of said abrasive surface thereto as said magnetic recording head is rotated and randomly moved across the upper surface of said polishing pad.
Claim 14
Dependent Claim
153 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head, the apparatus including a rotatable base having a flat upper surface, a polishing pad disposed on said flat surface and forming an abrasive upper surface, a workpiece holder disposed above said polishing pad for rotating said workpiece while urging said work surface against said abrasive surface with a substantially uniform contact pressure, an oscillatory motion generator drivingly connected to said holder for moving same randomly across said pad, the improvement comprising: polishing pad means including a first layer of resilient material disposed on said flat surface, and a flexible abrasive sheet overlaying the upper surface of said first layer and forming a resilient abrasive surface, whereby polishing of said spherical surface is accomplished by the conforming engagement of said abrasive surface thereto as said magnetic recording head is rotated and randomly moved across the upper surface of said polishing pad.
Claim 15
Dependent Claim
106 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 12 wherein said spherical surface is comprised of materials that have different hardness characteristics, said polishing pad including a second layer of resilient material overlaying said first layer and being comprised of a material that is harder than the material comprising said first layer, the upper surface of said second layer providing a stiffened interface with said abrasive sheet and reducing the conforming engagement of said abrasive surface with said spherical surface, thereby to reduce the tendency of said abrasive surface to erode softer portions of said spherical surface.
Claim 16
Dependent Claim
44 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 13 wherein said spherical surface includes stainless steel and mu metal materials, said first layer being a material having a hardness characteristic of at least 60 Durometer.
Claim 17
Dependent Claim
34 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 13 wherein said first layer is comprised of urethane, and said second layer is comprised of polyvinylchloride.
Claim 18
Dependent Claim
39 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 15 and including loading means coupled to said holder for urging said spherical surface against said abrasive surface with a preselected load.
Claim 19
Dependent Claim
31 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 16 wherein said preselected load is in the range between 1 and 8 pounds.
Claim 20
Dependent Claim
47 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 13 wherein said first layer comprises a plurality of laminations, a lamination disposed subjacent said abrasive sheet being characterized by a greater hardness characteristic than a lamination disposed farther therefrom.
Claim 21
Dependent Claim
47 words
In apparatus for polishing a substantially spherical surface of a magnetic recording head as recited in claim 13 wherein said first layer is comprised of a material characterized as having a variable density, the density of said material decreasing as its separation from said abrasive sheet increases.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |