Lens generator and tool cutter

In a lens generator for forming a curved surface in a lens blank having an unfinished surface to produce an ophthalmic lens, first mounting means for mounting a lens blank with said unfinished surface exposed, first cutting means for cutting into the unfinished surface of the lens blank to form said curved surface, said first cutting means including a lens cutting bit rotating about a first bit rotating axis, said lens cutting bit having at least one knife edge and a distal end, oscillating means for oscillating said first bit about an oscillation axis normal to said first bit rotating axis whereby the distal end of said lens cutting bit moves in a circular path within a plane of oscillation containing said first bit rotating axis, means for moving the lens blank along a circular path in a plane transverse to said plane of oscillation, past said distal end of said lens cutting bit whereby said lens blank is cut by said cutting means, first adjustment means for adjusting the radial distance of the distal end of said lens cutting bit from said oscillation axis whereby the radius of curvature of the surface cut into said lens blank along said plane of oscillation can be varied, and second adjustment means for adjusting the distance between the distal end of said lens cutting bit and the center of curvature of the circular path of the lens blank whereby the radius of curvature of the surface cut into said lens blank transverse to said plane of oscillation can be varied independently of said first adjustment means to form a compound curved surface in the lens blank.

A lens generator for cutting a rough lens surface in a lens blank and simultaneously cutting a tool complementary to said rough lens surface for use in polishing said rough lens surface, said lens blank having a body with a first finished lens surface and a second unfinished surface and having an optical axis, said generator comprising:

• lens holder means for holding the lens blank with said unfinished surface exposed;
• lens moving means for moving said lens holder means and the lens blank in a planar circular path with the optical axis of the lens blank extending radially of said circular path;
• lens cutting means for cutting into the body of the lens blank to form said rough lens surface opposite said finished surface, said lens cutting means including a lens cutting motor and a lens cutting bit rotated by said lens cutting motor about a first bit axis of rotation, said lens cutting bit having a distal end projecting from said lens cutting motor;
• tool holder means for holding a tool having an unfinished surface with said unfinished surface exposed;
• tool moving means for moving said tool holder means and the tool in a planar circular path within the plane of the planar circular path of said lens blank;
• tool cutting means for cutting into the body of the tool to form said tool surface complementary to said rough surface of said lens blank, said tool cutting means including a tool cutting motor and a tool cutting bit rotated by said tool cutting motor about a second bit axis of rotation, said tool cutting bit having a distal end projecting from said tool cutting motor;
• mounting means for mounting said lens and tool cutting means;
• and
• oscillation means for oscillating said mounting means about an oscillation axis so that said distal end of said lens cutting bit oscillates along a circular path with the rotation axis of said lens cutting bit extending radially thereof, said rotating bit oscillating in a plane normal to the plane in which said lens blank optical axis travels as said lens blank is moved along its circular path, said lens holder means and said lens cutting means being relatively positioned so that the oscillating path of said lens cutting bit intersects the path of said lens blank whereby said lens cutting bit cuts into said lens blank body forming a curved lens surface;
• said oscillating means further oscillating said mounting means about said oscillation axis so that said distal end of said tool cutting bit travels along a circular path with the tool bit rotation axis extending radially thereof, said rotating tool bit oscillating in a plane normal to the plane in which said tool travels as said tool is moved along its circular path, said tool holder means and said tool cutting means being relatively positioned so that the oscillating path of said tool cutting bit intersects the path of said tool whereby said tool bit cuts into said tool body forming a curved tool surface;
• said mounting means mounting said lens and tool cutting motors and said bits so that one of said bits extends radially outwardly relative to said oscillation axis and the other of said bits extends radially inwardly relative to said oscillation axis whereby said tool cutting bit forms a curved surface in said tool complementary to the curved surface cut into said lens blank.

A method of cutting a concave curved surface into a lens blank having a finished convex surface and an unfinished surface and said lens blank having an optical axis, said concave surface to be cut into said unfinished surface of said lens blank, said method comprising:

• mounting said lens blank in a fixture with said unfinished surface exposed;
• moving said lens blank along a first circular arc with said optical axis extending radially of said first circular arc with said unfinished surface disposed radially inward of said finished surface;
• rotating a cutting bit having an elongated shaft and at least one knife edge about the axis of said shaft;
• oscillating said cutting bit back and forth in a second circular arc with said shaft axis extending radially of said second arc and with said shaft axis oscillating in a plane transverse to the plane of said optical axis as said lens blank moves along said first circular arc;
• and
• positioning said lens blank and said cutting bit relative to one another so that said cutting bit intersects with said lens blank and cuts into said lens blank unfinished surface as said lens blank moves in said first arc and said bit moves in said second arc.