Electro-optical and electromagnetic determination of the position of scale divisions

Claim 1

A DEVICE FOR ELECTRICALLY DETERMINING THE POSITION OF A STRUCTURAL ELEMENT PROVIDED WITH A SCALE, COMPRISING, IN COMBINATION: (A) A MOVABLE STRUCTURAL ELEMENT PROVIDED WITH A SCALE COMPOSED OF MARKINGS AND WHICH MOVES THROUGH A MEASURING RANGE; (B) MEANS FOR INDICATING AT A PLURALITY OF STATIONS THE PRESENCE OF A MARKING OF SAID SCALE WITHIN SAID MEASURING RANGE; AND (C) ELECTRICAL POSITION DETERMINING MEANS INCLUDING (1) AT LEAST THREE TRANSDUCER HEADS AT SAID STATIONS SENSITIVE TO THE INDICATION OF SAID MARKING FOR CONTINUOUSLY SCANNING SAID SCALE, SAID HEADS BEING ARRANGED TO PRODUCE A MAXIMUM OUTPUT WHEN THE MARKING IS IN A PREDETERMINED CENTRAL POSITION AND ALSO WHEN IT IS DISPLACED BY A PREDERMENED DISTANCE FROM SAID POSITION OR BY AN INTEGER MULTIPLE OF SAID PREDETERMINED DISTANCE, AT LEAST THREE OF SAID TRANSDUCER HEADS, AT ANY MARKING DISPLACEMENT WITHIN THE MEASURING RANGE BETWEEN THE INTEGER MULTIPLES OF SAID DISTANCE, SENSING THE POSITION OF SUCH MARKING AND GENERATING OUTPUT SIGNALS OF APPRECIABLE MAGNITUDE, (2) STAGES OF PERIODICALLY INTERROGATING AND ADDIN THE OUTPUT SIGNALS OF SAID TRANSDUCER HEADS FOR A DEFINITE AND AT LEAST APPROXIMATELY CONSTANT TIME INTERVAL IN THE SAME ORDER IN EACH PERIOD FOR GENERATING AN ALTERNATING SUMMATION SIGNAL, AND (3) A COMPARATIVE SECTION RECEIVING THE SUMMATION SIGNAL WHICH IS DEPENDENT UPON THE HEAD SCANNING AND INTERROGATION, AND RECEIVING A SIGNAL SINGIFICANT OF THE INITIATION OF THE INTERROGATION PERIOD AND, BY COMPARATIVE PHASE MEASUREMENT, GIVING AN INDICATION OF THE POSION OF SAID MARKING.

Claim 2

A DEVICE FOR ELECTRICALLY DETERMINING THE POSITION OF A STRUCTURAL ELEMENT PROVIDED WITH A SCALE, COMPRISING, IN COMBINATION: (A) A MOVABLE STRUCTURAL ELEMENT PROVIDED WITH A SCALE COMPOSED OF MARKINGS AND WHICH MOVES THROUGH A MEASURING RANGE; (B) MEANS FOR INDICATING AT A PLURALITY OF STATIONS THE PRESENCE OF A MARKING OF SAID SCALE WITHIN SAID MEASURING RANGE; AND (C) ELECTRICAL POSITION DETERMINING MEANS INCLUDING (1) AT LEAST THREE TRANSDUCER HEADS AT SAID STATIONS SENSITIVE TO THE INDICATION OF SAID MARKING FOR CONTINUOUSLY SCANNING SAID SCALE, SAID HEADS BEING ARRANGED TO PRODUCE A MAXIMUM OUTPUT WHEN THE MARKING IS IN A PREDETERMINED CENTRAL POSITION AND ALSO WHEN IT IS DISPLACED BY A PREDERMENED DISTANCE FROM SAID POSITION OR BY AN INTEGER MULTIPLE OF SAID PREDETERMINED DISTANCE, AT LEAST THREE OF SAID TRANSDUCER HEADS, AT ANY MARKING DISPLACEMENT WITHIN THE MEASURING RANGE BETWEEN THE INTEGER MULTIPLES OF SAID DISTANCE, SENSING THE POSITION OF SUCH MARKING AND GENERATING OUTPUT SIGNALS OF APPRECIABLE MAGNITUDE, (2) STAGES OF PERIODICALLY INTERROGATING AND ADDIN THE OUTPUT SIGNALS OF SAID TRANSDUCER HEADS FOR A DEFINITE AND AT LEAST APPROXIMATELY CONSTANT TIME INTERVAL IN THE SAME ORDER IN EACH PERIOD FOR GENERATING AN ALTERNATING SUMMATION SIGNAL, AND (3) A COMPARATIVE SECTION RECEIVING THE SUMMATION SIGNAL WHICH IS DEPENDENT UPON THE HEAD SCANNING AND INTERROGATION, AND RECEIVING A SIGNAL SINGIFICANT OF THE INITIATION OF THE INTERROGATION PERIOD AND, BY COMPARATIVE PHASE MEASUREMENT, GIVING AN INDICATION OF THE POSION OF SAID MARKING.