Apparatus for photographically forming circular scales from linear strips

Claim 1

APPARATUS FOR FORMING CIRCULAR SCALES FROM A LINEAR STRIP BY PHOTOGRAPHY COMPRISING: AN APERTURED STRIP GUIDE; DIGITAL MEANS CONTINUOUSLY TRANSPORTING A LINEAR STRIP OVER THE GUIDE WHICH STRIP INCLUDES SPACED MARKINGS REPRESENTING AT LEAST PART OF THE SCALE TO BE PRODUCED; A ROTATABLE PLATE CARRIER HAVING MEANS FOR SUPPORTING A CIRCULAR PHOTOGRAPHIC PLATE; TOOTHED GEARING AND FINAL DRIVE MEANS COUPLING THE DIGITAL MEANS AND THE PLATE CARRIER AND CONTINUOUSLY ROTATING THE PLATE CARRIER AT A PREDETERMINED SPEED IN RELATION TO THE LINEAR SPEED OF THE STRIP; MEANS ILLUMINATING THE GUIDE APERTURE AND THE PART OF THE STRIP OVER THE GUIDE; AN OPTICAL SYSTEM POSITIONED TO CAST AN IMAGE OF THE APERTURE AND STRIP PART ON THE PHOTOGRAPHIC PLATE AT A REDUCTION RATIO OF AT LEAST 20:1, A CIRCULAR SCALE BEING THEREBY FORMED, THE OPTICAL SYSTEM INCLUDING A MOVABLE PROJECTION LENS AND MEANS FOR MOVING THE PROJECTION LENS RADIALLY RELATIVE TO THE PLATE CARRIER AND THE AXIS OF ROTATION OF THE CARRIER TO ENABLE FORMATION OF AT LEAST ONE OTHER CIRCULAR SCALE, THE WIDTH OF THE ILLUMINATED APERTURE BEING LIMITED SUCH THAT ANY POINT ON THE ILLUMINATED PART OF THE STRIP HAS SUBSTANTIALLY NO MOTION RELATIVE TO THE MOTION OF THE PLATE CARRIER.