Magneto-electric transmitter of the proximity type

Claim 1

A MAGNETICALLY RESPONSIVE SIGNAL TRANSMITTER FOR RESPONDING TO THE PRESENCE OF A MAGNETIZABLE MATERIAL, COMPRISING A HALL-VOLTAGE GENERATOR HAVING A MAGNETIC FIELD STRUCTURE WITH A FIELD GAP AND HAVING A HALL PLATE IN SAID GAP, SAID STRUCTURE COMPRISING TWO POLE PIECES OF MAGNETIZABLE MATERIAL SPACED FROM EACH OTHER AT AREAS OF THE SAME POLARITY TO FORM SAID GAP BETWEEN SAID SAME POLARITY POLE PIECES AND HAVING TWO PERMANENT MAGNETS OF SUBSTANTIALLY THE SAME STRENGTH HAVING RESPECTIVE POLES OF THE SAME POLARITY MAGNETICALLY JOINED WITH SAID TWO POLE PIECES, A SOFT-MAGNETIC YOKE MAGNETICALLY INTERCONNECTING THE OTHER POLES OF SAID RESPECTIVE TWO MAGNETS AND FORMING A MAGNETIC CIRCUIT TOGETHER WITH SAID TWO MAGNETS NORSAID TWO POLE PIECES, SAID MAGNETIC CIRCUIT HAVING NORMALLY IN SAID GAP AND SAID HALL PLATE A RESULTANT FIELD STRENGTH SUBSTANTIALLY EQUAL TO THE ZERO VALUE SO THAT THE GENERATED HALL-VOLTAGE IS SUBSTANTIALLY ZERO, SAID HALL PLATE BEING POSITIONED IN THE GAP BETWEEN SAID POLE PIECES IN SAPCED RELATION WITH EACH OF SAID POLE PIECES IN A MANNER WHEREBY PROXIMITY OF A MAGNETIZABLE MATERIAL CREATES MAGNETIC DISTRUBANCE WHICH CAUSES A CHANGE IN GAP FIELD STRENGTH AND A CHANGE IN THE HALL-VOLTAGE GENERATED BY SAID SIGNAL TRANSMITTER.