Program control system to regulate tool speed

Claim 1

IN AN ARRANGEMENT FOR CONTROLLING THE POSITION WHICH TWO PARTS OCCUPY RELATIVE TO EACH OTHER, A SYSTEM FOR CONTROLLING THE SPEED AT WHICH ONE OF THE PARTS MOVES RELATIVE TO THE OTHER, SAID SYSTEM COMPRISING, IN COMBINATION: (A) MEANS FOR SUPPLYING DATA REPRESENTING THE NOMINAL SPEED OF SAID ONE PART; (B) MEANS FOR DERIVING THE ACTUAL SPEED OF SAID ONE PART, SAID LAST-MENTIONED MEANS INCLUDING A SCALE HAVING A SUBDIVIDED TRACK EXTENDING IN THE DIRECTION OF MOVEMENT AND MEANS FOR SCANNING SAID TRACK, SAID SCALE AND SCANNING MEANS BEING CARRIED BY SAID PARTS, RESPECTIVELY, SAID SPEED DERIVING MEANS COMPRISING MEANS FOR COUNTING THE NUMBER OF SUBDIVISIONS SCANNED BY SAID SCANNING MEANS, MEANS FOR PERIODICALLY RESETTING SAID COUNTING MEANS, AND STORAGE MEANS CONNECTED TO THE OUTPUT OF SAID COUNTING MEANS FOR STORING THE NUMBER OF SUBDIVISIONS COUNTED BY SAID COUNTING MEANS DURING EACH PERIOD;