Claims
- 1. The method of forming a convex front surface portion of variable curvature for use in the formation of spectacle lenses for correction of presbyopia and aphakia which surface is characterized by having a pair of orthogonal principal planes which intersect said front surface normally at all points, the first of said principal planes, generally horizontal, intersecting said front surface in a great arc, and the second of said principal planes, generally vertical, intersecting said front surface in a principal curve; comprising mounting a workpiece in a holder, causing an abrading tool to cut said workpiece symmetrically on opposite sides of said principal curve while following a path in a plane at right angles to said principal curve and to said second principal plane, and causing the abrading point of said tool to follow a conic pattern of eccentricity zero and greater than zero, after each cut causing movement of said workpiece with respect to said tool by a small increment along a predetermined substantially elliptical portion of said principal curve and keeping said principal curve in said second plane, repeating said cuts while causing said movement through successive increments to follow said predetermined elliptical curve in said second plane while varying the eccentricity and apical radius of curvature of said conic pattern progressively and regularly for successive cuts, said increments being so closely spaced that said workpiece has an almost smooth contour.
- 2. The method as defined in claim 1, wherein said conic pattern is derived from at least a portion of a cone.
Parent Case Info
This is a division of application Ser. No. 322,488, filed Jan. 10, 1973, now abandoned.
US Referenced Citations (4)
Divisions (1)
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Number |
Date |
Country |
Parent |
322488 |
Jan 1973 |
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