Single block mounting system for surfacing and edging of a lens blank and method therefor

A system for shaping the rear surface of a lens blank, for polishing said rear surface and for edging a given shape into the blank for fitting into a selected frame opening of an eyeglass pair, said system comprising:

• a lens blank and block assembly, said lens blank of said assembly having a first finished surface facing the block and a second rear surface facing away from the block, the first surface being fixedly bonded with said block such that the centers of the block and the lens are coincident with one another and define a block center;
• cutting means for cutting a given shape in the rear surface of said lens blank by rotating said assembly about a cutting axis of rotation coincident with said block center to cause the lens blank to have the optical characteristics specified by prescription data;
• said cutting means including a rotatable holding means for releasably mounting said assembly to said machine such that said block center is located coincidentally with said cutting axis of rotation and is disposed at a given angular orientation coincident with a given radial reference axis;
• control means associated with said cutting means for creating a custom lap for off-axis finishing of the worked on second surface of said lens blank such that the custom lap is formed with a surface correspondingly shaped to fit the given shape cut in the rear surface of the lens and means for holding said custom lap in said cutting means at a given orientation with respect to said block center and said given radial reference axis in said cutting machine;
• means formed on said assembly for holding it in registry with means for finishing said second surface of said lens regardless of the surface contour formed thereon and for orienting said assembly with respect to said custom lap while said assembly is mounted in said finishing means such that the cut surfaces of said lap and said lens blank mate with each other;
• edging means for edging a given shape in said lens blank while fixed to said block assembly and rotated relative to an edging tool about an edging means central axis;
• and
• means provided on said block for mounting said assembly to said edging means for rotation about said edging means central axis such that the edging means central axis is located coincidentally with said block center and said block is angularly oriented on said edging means relative to said given radial reference axis whereby said edging of said block and lens blank assembly is accomplished without re-blocking after said lens second surface is cut and finished.