Hearing-aid sound transducer

Claim 1

A MINIATURE, HIGH EFFICIENCY SOUND TRANSDUCER COMPRISING A BOX-LIKE CASING OF MAGNETIC MATERIAL CONTAINING A U-SHAPED ARMATURE HAVING ONE ARM ADJACENT THE BOTTOM OF SAID CASING AND THE OTHER ARM SOMEWHAT ABOVE AND PARALLEL THERETO, THE WEB END OF SAID ARMATURE BEING SUPPORTED BY SAID CASING, A COIL ENCIRCLING A PORTION OF THE FLUX PATH OF SAID ARMATURE NEAR ITS WEB END, A U-SHAPED POLE-PIECE HAVING ONE ARM AFFIXED TO THE LOWER ARM OF SAID ARMATURE AND ITS OTHER ARM ABOVE THE FREE END OF THE UPPER ARM OF SAID ARMATURE, A PAIR OF PERMANENT MAGNETS MOUNTED ON INNER PORTIONS OF SAID POLE PIECE ARMS RESPECTIVELY ABOVE AND BELOW THE FREE END OF SAID UPPER ARMATURE ARM, SAID MAGNETS HAVING RELATIVELY HIGH PERMEABILITY TO ALTERNATING SIGNAL MAGNETIC FLUX OF THE TRANSDUCER AND PROJECTING PERMANENT UNIDIRECTIONAL MAGNETIC FLUX DIRECTLY INTO SAID FREE ARMATURE END, A DRIVE PIN ATTACHED TO SAID UPPER ARM OF SAID ARMATURE NEAR ITS CENTER, AND A DIAPHRAGM EXTENDING ACROSS THE UPPER REGION OF SAID CASING, AND BEING ATTACHED NEAR ITS CENTER TO SAID DRIVE PIN.