Reproducing apparatus

Claim 1

IN APPARATUS FOR REPRODUCING A CONTOUR OF A PATTERN ON A WORKPIECE, THE COMBINATION OF TOOL AND WORKPIECE SUPPORTS SO ARRANGED AS TO HAVE RELATIVE MOVEMENT IN TWO MUTUALLY TRANSVERSE PATHS, DRIVE MEANS FOR PRODUCING THE RELATIVE MOVEMENT OF THE SUPPORTS ALONG THE TWO PATHS, AND A TRACER MECHANISM ARRANGED TO HAVE MOVEMENT CORRESPONDING TO THE RELATIVE MOVEMENT BETWEEN THE TOOL AND WORKPIECE SUPPORTS, THE TRACER MECHANISM COMPRISING A PHOTOCELL MOUNTING MEMBER REVOLVABLY POSITIONED ON THE TOOL SUPPORT, A SERIES OF PHOTOCELLS ARRANGED ON THE MOUNTING MEMBER INCLUDING STEERING PHOTOCELLS ADAPTED TO SENSE PARALLEL MISALIGNMENT THEREOF RELATIVE TO THE CONTOUR AND TO DEVELOP CORRESPONDING STEERING ERROR SIGNALS AND ON-COURSE PHOTOCELLS ADAPTED TO SENSE OFF-COURSE DEVIATIONS THEREOF FROM THE CONTOUR AND TO DEVELOP A CORRESPONDING OFF-COURSE ERROR SIGNAL, A POSITIONING MOTOR REVOLVING THE PHOTOCELL MOUNTING MEMBER IN ACCORDANCE WITH THE STEERING ERROR SIGNALS SO AS TO CAUSE THE STEERING PHOTOCELLS TO IN PARALLEL ALIGNMENT WITH THE CONTOUR, FIRST MEANS MANEUVERABLE BY THE POSITIONING MOTOR SO AS TO DEVELOP A STEERING CONTROL SIGNAL REPRESENTING THE DIRECTION THE MOUNTING MEMBER IS REQUIRED TO BE REVOLVED BY THE POSITIONING MOTOR SO AS TO CORRECT FOR STEERING ERRORS, SECOND MEANS COMMUNICATING WITH THE ON-COURSE PHOTOCELLS AND MANEUVERABLE BY THE POSITIONING MOTOR SO AS TO DEVELOP AN OFF-COURSE CONTROL SIGNAL CORRESPONDING IN MAGNITUDE AND POLARITY TO THE OFFCOURSE ERROE SIGNAL, AND A SUMMING CIRCUIT COMMUNICATING WITH THE FIRST AND SECOND MEANS AND ARRANGED SO AS TO PRODUCE AN EQUIVALENT REGULATING SIGNAL FROM THE CONTROL SIGNALS FOR CONTROLLING THE OPERATION OF THE DRIVE MEANS SO THAT RELATIVE MOVEMENT OF THE SUPPORTS PRODUCED BY THE DRIVE MEANS WILL CAUSE THE CONTOUR OF THE PATTERN TO BE REPRODUCED ON THE WORKPIECE.