Patent ID: 6832946
Filing Date: 2004-12-21
Classification: B24B

Abstract:
A lens grinding apparatus comprising:a lens rotation shaft for sandwiching and rotating a spectacle lens; drive means for driving the lens rotation shaft; a grindstone for grinding a spectacle lens; shaft-to-shaft distance adjusting means for controlling a distance between a lens rotation shaft and a grindstone; and calculation control means for controlling a rotation speed of the lens rotation shaft, wherein the calculation control means operates in such a manner that a predetermined angle for the rotation reference position when the spectacle frame lens shape is expressed in spherical coordinates is referred to as a rotation angle while an angle for the rotation reference position when the lens shape in contact with the grindstone is expressed in spherical coordinates is referred to as a contact angle and calculation is performed to obtain a rotation angle change of the lens rotation shaft holding the spectacle lens per a predetermined time as a rotation angular speed and a contact angle change per a predetermined time as a contact angular speed, so that the rotation speed of the lens rotation shaft can change with an arbitrary combination ratio of the speed component in which the rotation angle rotates at a constant speed and the speed component in which the contact angle rotates at a constant speed.