Automatic lens grinding machine

Claim 1

AN IMPROVEMENT IN A LENS GRINDING MACHINE OF A TYPE FOR ABRADING THE CONCAVE SIDE OF A LENS BLANK HAVING A KNOWN, MEANS CURVE ON THE CONVEX SIDE THEREOF, SAID BLANK HAVING A CENTER AXIS EXTENDING THROUGH THEREOF, APOGEE OF SAID CONVEX SURFACE, A BASE, A TAILSTOCK SUPPORTING ASSEMBLY MOUNTED ON SAID BASE, A CHUCK MOUNTED ON SAID ASSEMBLY FOR SUPPORTING SAI LENS BLAND AND HAVING A CHUCK FACE IN A PLANE TRANSVERSE TO SAID CENTER AXIS WHEN SAID LENS BLANK IS SUPPORTED BY SAID CHUCK, AN ABRADING TOOL HAVING AN ARCUATE GRINDING EDGE, A SUPPORT PIVOTALLY MOUNTED ON SAID BASE FOR SWINGING SAID GRINDING EDGE THROUGH AN ABRADING SWEEP WHICH INTERSECTS SAID AXIS, SAID IMPROVEMENT COMPRISING: AN ANNULAR SPACER OF KNOWN DIMENSIONS BETWEEN SAID CONVEX SURFACE AND SAID CHUCK FACE, SAID SPACER HAVING A FIRST END IN CONTACT WITH SAID CHUCK FACE AND A SECOND END CONTACTING SAID BLANK AT A PLURALITY OF POINTS ON SAID CONVEX SURFACE IN A SECOND PLANE PARALLEL TO SAID FIRST PLANE, SAID POINTS OF CONTACT BEING OF EQUAL AND KNOWN RADIAL DISTANCES FROM SAID CENTER AXIS SUCH THAT SAID APOGEE IS SUPPORTED A KNOWN DISTANCE FROM SAID FIRST PLANE AN AMOUNT EQUAL TO THE DISTANCE BETWEEN THE FIRST AND SECOND ENDS OF SAID SPACER MINUS THE DISTANCE DEFINED BY A NORMAL FROM SAID APOGEE TO SAID SECOND PLANE, A PIN SUPPORTED ALONG THE SAME VERTICAL AXIS AS SAID ABRADING EDGE, A POSITIONING YOKE SLIDABLY THE SAME VERTICAL AXIS AS SAID FOR HORIZONTAL MOVEMENT TOWARD AND AWAY FROM SAID PIN, POSITIONING MEANS FOR LOCATING SAID YOKE A FIXED DISTANCE FROM SAID FIRST PLANE WHEREBY WHEN SAID TAILSTOCK CARRIERS SAID YOKE INTO ENGAGEMENT WITH SAID PIN, SAID FIRST PLANE IS SAID FIXED DISTANCE FROM SAID POINT OF INTERSECTION, AND SECOND MEANS FOR VISUALLY REPRESENTING AND RETRACTING SAID FACE FROM SAID POINT AN AMOUNT EQUAL TO SAID DISTANCE DEFINED BY SAID NORMAL.