Electromagnetic transducers

Claim 1

AN ELECTROMAGNETIC TRANSDUCER, INCLUDING A MASS, A SPRING SUSPENSION FOR SAID MASS, A PAIR OF ARMATURES CONNECTED TO SAID MASS, A PAIR OF COILS, ONE COIL POSITIONED ADJACENT EACH ARMATURE, A CORE FOR EACH COIL, SAID ARMATURES BEING SPACED FROM SAID CORE TO FORM AN AIR GAP BETWEEN EACH ARMATURE AND ITS ADJACENT CORE, SAID MASS BEING MAGNETICALLY PERMEABLE AND OF LOW COERCIVE FORCE, A PLURALITY OF RADIAL POLE RINGS MOUNTED ON SAID MASS IN LONGITUDINALLY SPACED POSITION, TO PROVIDE A PAIR OF END POLE MEMBERS AND AN INTERMEDIATE POLE MEMBER, A PLURALITY OF COMPLEMETARY RADIAL POLE RINGS POSITIONED ONE AT EACH OF SAID END POLE MEMBERS, AND A COMPLEMENTARY INTERMEDIATE POLE RING, SAID COMPLEMENTARY POLE RING MEMBERS BEING SPACED FROM SAID FIRSTMENTIONED POLE MEMBERS TO FORM A PAIR OF END GAPS AND AN INTERMEDIATE GAP, A PAIR OF SPACED COILS SURROUNDING SAID MASS AND MAGNETICALLY COUPLED WITH SAID MASS AND SAID GAPS AND POSITIONED BETWEEN SAID INTERMEDIATE GAP AND SAID END GAPS, WHEREBY ON ENERGIZING OF SAID COILS, A PAIR OF MAGNETIC FIELDS ARE FORMED WHICH ADD AT SAID SAID INTERMEDIATE GAP, AND MEANS TO SENSE THE DISPLACEMENT OF SAID MASS SAID LAST-NAMED MEANS INCLUDING SAID ARMATURES AND THE COILS POSITIONED ADJACENT TO SAID ARMATURES.