Plastic lens contour cutting machine

Claim 1

An improved machine for cutting, edging, contouring, and beveling the periphery of a plastic lens, said machine being of the type having a head mounted on a base and carrying a lens pattern and a plastic lens which is to be cut and has a base curvature, means for rotating said pattern and said lens about a common axis, wherein the machine includes a carriage mounted on said base and having a pattern follower in bearing contact with said pattern and having a rotatable cutter with a cutting edge capable of engaging said periphery of said lens, said cutting edge forming a beveling means, means for moving said carriage substantially perpendicular toward and away from said axis, said movement effecting an engagement of said cutter with said periphery of said lens, the improvement comprising: said cutter having a cutter edge of a metal of a high hardness and rotatable at high speed, said cutter having a cutting face and a radial plane of rotation, said cutting face forming a clearance angle with said radial plane, said face operative to direct particles along said face away from said radial plane of rotation; and bevel aligning means including base curve cam means connected to said head and cam tracing means connected to said carriage, said cam means having a surface forming the same base curvature as said lens, said tracing means being in bearing contact with said surface for effecting a movement of said head with said lens in a first direction to a position that aligns the center of said lens with said beveling means, said aligning means including biasing means connected to said head and said base and effecting a movement of said head in a second direction resulting in bearing contact of said surface of said cam means against said tracing means, said surface of said base curve cam means including a plurality of discrete sectors, each of said sectors having a different base curvature surface, said cam means rotatable to effect bearing alignment between the surface of any selected sector and said tracing means, whereby when said selected sector has a surface forming the same base curvature as the base curvature of said lens, said tracing means effects a movement of said head with said lens in said first direction to a position that aligns the center of said lens with said beveling means, whereby when said lens and said lens pattern are rotated and said cutter is rotated at high speed, said carriage moves toward said axis effecting an engagement of said cutter with said lens periphery to cut and edge said plastic lens and simultaneously form a bevel at the center of said periphery.