ANNULAR GASKET FOR USE IN THE CASTING OF OPHTHALMIC OR OPTICAL LENSES OF ORGANIC MATERIAL, AND METHOD OF USING SUCH A GASKET

摘要

An annular gasket for use in the moulding of ophthalmic or optical lenses of organic material, comprises two axially spaced ridges on its inner periphery arranged to cooperate tightly with two mould shells. At least one of the annular ridges is formed at the end of an elastically deformable annular flange extending around the inner periphery at an angle to the axis of the gasket. The flange projects both from a corresponding transverse face of the gasket and from its internal peripheral face.