Stepper motor control and step detector

Claim 1

A STEPPER MOTOR AND STEP DETECTOR COMPRISING, IN COMBINATION: MAGNETIC FIELD GENERATING COILS POSITIONED TO ESTABLISH A MAGNETIC FIELD IN GIVEN SELECTED DIRECTIONS DEPENDING UPON WHICH COILS ARE ENERGIZED; A ROTOR RESPONSIVE TO SAID MAGNETIC FIELD TO ALIGN ITSELF IN THE DIRECTION IN WHICH SAID MAGNETIC FIELD IS ESTABLISHED; A CONTROL MEANS HAVING OUTPUTS CONNECTED TO SAID COILS SUCH THAT SIGNALS ON SELECTED ONES OF SAID OUTPUTS ENERGIZE SELECTED ONES OF SAID COILS, SAID CONTROL MEANS HAVING A PULSE INPUT TERMINAL AND BEING RESPONSIVE TO SUCCESSIVE PULSES RECEIVED ON SAID TERMINAL TO STEP SAID MAGNETIC FIELD THROUGH DISCRETE ANGLES AND THEREBY SUCCESSIVE STEP SAID ROTOR THROUGH SAID DISCRETE ANGLES; A STEP DETECTOR INCLUDING MEANS COUPLED TO SAID ROTOR AND RESPONSIVE TO STEPPING OF SAID ROTOR FROM A GIVEN POSITION TO ITS NEXT SUCCESSIVE POSITION TO PROVIDE A SIGNAL; COINCIDENCE CIRCUIT MEANS CONNECTED TO PROVIDE A SIGNAL AND CONNECTED TO SAID OUTPUTS OF SAID CONTROL MEANS, SAID COINCIDENCE CIRCUIT MEANS BEING RESPONSIVE ONLY TO A COINCIDENCE OF SAID SIGNAL AND A SIGNAL ON ONE OF SAID OUTPUTS TO SAID COILS TO STEP SAID MAGNETIC FIELD TO SAID NEXT SUCCESSIVE POSITION TO PROVIDE A GIVEN SIGNAL; AND ENABLING MEANS CONNECTED TO RECEIVE SAID GIVEN SIGNAL AND ENABLE A NEXT SUCCESSIVE PULSE TO BE RECEIVED AT SAID PULSE INPUT OF SAID CONTROL MEANS, SAID ENABLING MEANS BLOCKING PULSES TO SAID INPUT IN THE ABSENCE OF SAID GIVEN SIGNAL, WHEREBY SAID MAGNETIC FIELD CANNOT BE STEPPED TO A NEXT SUCCESSIVE POSITION UNTIL SUCH TIME AS SAID ROTOR HAS BEEN STEPPED TO SAID POSITION IN ALIGNMENT THEREWITH.