Device and method for centrifugally casting articles
AssigneeInternational Hydron Corporation
InventorDavid L. Rawlings
Life of this patent
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Abstract
A device and method for spin casting articles, such as lenses, employing a rotatable polymerization column in conjunction with a plurality of molds such that the column is adapted to accommodate a plurality of gravity fed molds in a loose mating engagement that insures rotation of the molds to be synchronized to the speed of rotation of the column to produce quality spun cast articles.
Claims11
A device for casting contact lenses comprising a rotatable polymerization column having an inlet end and an outlet end, said polymerization column adapted for rotation about a vertical axis and adapted for receiving a plurality of gravity fed free falling molds containing a polymerizable or curable composition;
- cooperative mating means associated with said polymerization column and said molds for aligning said plurality of said molds in vertical series within said polymerization column, said cooperative mating means adapted for maintaining the rotation of said molds in synchronization with the same speed of rotation of said polymerization column;
- and gas feed means associated with the inner surface of said polymerization column and the outer wall of said molds to accommodate the flow of a gaseous medium through said polymerization column.
A method for centrifugally casting of shaped contact lenses comprising the steps:
- (a) providing an elongated tubular polymerization zone within a polymerization column, said column being adapted for receiving a plurality of gravity fed, free falling molds, and said polymerization column and said molds having cooperative mating means for aligning said molds within said polymerization column;
- (b) gravity feeding into one end of said polymerization column a series of said molds each containing a polymerizable or curable composition;
- (c) rotating said polymerization column such that the cooperative mating means associated with said polymerization column and said molds maintains the rotation of said molds in synchronization with the same speed of rotation of said polymerization column, said rotation speed being sufficient to cause the polymerizable or curable composition to flow radially outward by centrifugal force in the cavity of each of said molds thereby said composition assuming a predetermined shaped contact lenses;
- and
- (d) stopping the rotation of the polymerization column and withdrawing said gravity fed molds from the opposite end of said polymerization column after at least said polymerizable or curable composition is formed into a predetermined shaped contact lenses in said polymerization zone.
Dependencies are inferred from the claim text.