US 5,775,973 A · Method and apparatus for grinding the rim of a lens

Abstract

A method of processing the rim of a lens is provided which includes the step of grinding the rim of a lens (LE) with a grindstone (6) so as to fit the configuration of an eyeglass frame while rotating and moving the lens (LE) toward and away from the grindstone (6) at intervals of a rotational angle (n.DELTA..theta.) in accordance with lens processing data (.rho.n, n.DELTA..theta.) which have been measured by a configuration measuring portion (46). The method further includes the steps of, in accordance with the data (.rho.n, n.DELTA..theta.) and the radius of curvature of the grindstone (6), obtaining a displacement angle (d.theta.n) between an assumed processing point at a radius vector (.rho.n) of the rotational angle (n.DELTA..theta.)n=0, 1, 2, 3, . . . i! and a true processing point where the lens (LE) comes into contact with the grindstone (6) at the rotational angle (n.DELTA..theta.), and lowering a rotational angular speed of the lens (LE) at an angular interval (n) between (n-1.DELTA..theta.) and (n.DELTA..theta.) as the displacement angle (d.theta.n) at the rotational angle (n.DELTA..theta.) becomes larger so that the ground quantity of the rim of the lens (LE) becomes substantially constant.

Claims8

Dependent claims

A method of processing a rim of a lens, which comprises the step of grinding the rim of the lens to be processed with a grindstone so as to fit a configuration of an eyeglass while rotating and moving the lens toward and away from said grindstone at intervals of a rotational angle n.DELTA..theta., in accordance with data (.rho.n, n.DELTA..theta.) for processing the rim of the lens, said data having obtained by configuration measuring means;

wherein, from said data (.rho.n, n.DELTA..theta.) and a radius of curvature of said grindstone, a displacement angle d.theta.n is calculated between an assumed processing point at a radius vector .rho.n of the rotational angle n.DELTA..theta. n=0, 1, 2, 3, . . . i! and a true processing point where the lens comes into contact with said grindstone at the rotational angle n.DELTA..theta..

An apparatus for processing a rim of a lens, comprising:

a pair of lens rotating shafts which are coaxially disposed and hold the lens to be processed therebetween;
rotation driving means for rotating said lens rotating shafts;
a rotatable grindstone disposed below the lens;
up-down means for raising and lowering said lens rotating shafts in accordance with lens processing data (.rho.n, n.DELTA..theta.) measured by configuration measuring means for measuring a configuration of a lens frame;
and
an arithmetic control circuit for controlling said rotation driving means and said up-down means;
wherein according to said lens processing data (.rho.n, n.DELTA..theta.) and a radius R of curvature of said grindstone, said arithmetic control circuit calculates a displacement angle d.theta.n between an assumed processing point P at a radius vector .rho.n of a rotational angle n.DELTA..theta. n=0, 1, 2, 3, . . . i! and a true processing point P' where the lens comes into contact with said grindstone at the rotational angle n.DELTA..theta., and controls a rotational angular velocity of said lens rotating shafts in accordance with said displacement angle d.theta.n so that time during which said grindstone stays at said rotational angle n.DELTA..theta.becomes substantially constant.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for grinding the rim of a lens

Life of this patent

Method and apparatus for grinding the rim of a lens

Life of this patent

Abstract

Claims8