GB249094A - Apparatus for grinding lenses - Google Patents

Abstract

249,094. Optical Development Corporation, (Assignees of Fink, E. J.). March 10, 1925, [Convention date]. Lenses, grinding.-A machine for grinding a number of lenses simultaneously consists of a number of grinding-wheels 14 carried by a spindle 15, the wheels operating upon lens blanks mounted upon elements 18, which are carried by a slowly rotating drum 10 beneath the grinding-wheels. The elements 18 are curved and occupy about one fifth of the periphery of the drum, being located between pins 20 and several, sets of elements, which are shorter than the drum fitting at their ends between flanges 19 on the drum; the radius of curvature of the underside 18<a> of the elements is slightly less than that of the surface 10<a> of the drum, so that the elements rest at their edges only upon the drum, thus giving accurate seating on the drum, whereby the lenses are all at the same distance from the axis of the drum. The elements carrying the lenses are placed in stacks in guides 22a, 22<b>, 22<c> and are fed on to the drum by members 23 pressed by springs 24; rotation of the drum carries the elements beneath the grinding-wheels, after which the elements fall from the drum and down guide-rails 24a, 24<b>, 24<c>. Whilst upon the drum, the elements are held down thereon by rubber belts 26, mounted on rollers 27 in casings 28, the lower runs of the belts engaging recesses 18<c> in the elements. The elements have therein recesses 37, Fig. 2, in which the moulded lens blanks 41 are mounted by means of pitch, outlets allowing tho excess pitch to escape. The drums map be polygonal or of other shape instead of cylindrical. The several sets of elements may be in staggered relationship on the drum, so that the stage of grinding is different in each set. Water is supplied to the grinding-wheels during grinding.