Method of generating a toric surface on a molding tool
AssigneeBausch & Lomb Incorporated
InventorsRichard J. Fleenor, Kenneth L. Opdyke
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Abstract
An improved method for generating a toric surface on a molding tool for forming contact lens molds comprises: (a) providing a tool which comprises an elongated body and a molding portion at one end of the tool, wherein the molding portion comprises a surface which is substantially spherical; (b) applying a force to the elongated body so as to distort the spherical surface of the molding portion; (c) machining a substantially spherical curve in the distorted surface while maintaining the applied force; and (d) releasing the applied force, wherein the spherically cut surface assumes a toric shape upon release of the applied force.
Claims9
An assembly comprising:
- (a) a tool which comprises an elongated body and a curved surface at an upper end of the tool, said elongated body comprising a cylindrical shell including a cavity extending transversely through said cylindrical shell such that application of diametrically opposed forces on the cylindrical shell distorts the shape of the curved surface;
- (b) a collet comprising:
- (i) a base;
- and
- (ii) a pair of diametrically opposed arms extending longitudinally from said base for receiving and supporting the cylindrical shell of said tool therebetween, wherein said arms are circumferentially separated from each other by a pair of longitudinally extending diametrically opposed spaces and comprise arcuate interior surfaces which define a central cavity in which the cylindrical shell of said tool is received and supported, and said arms comprising tapered portions at distal ends thereof such that a thickness of the tapered portions increases towards the distal ends;
- and
- (c) tightening means for forcing the distal ends of said arms towards each other, whereby the arms exert diametrically opposed forces on the cylindrical shell of a tool received and supported therein.
A tool comprising an elongated body and an optically smooth toric molding surface at an upper end of the tool, said elongated body comprising a cylindrical shell including a cavity extending transversely through said cylindrical shell.
Dependencies are inferred from the claim text.