Piezoelectric accelerometer

Claim 1

THE COMBINATION COMPRISING A PLATE OSCILLATABLE AT A VARIABLE FREQUENCY, SAID PLATE INCLUDING A FIRST ELECTRICAL CONDUCTOR, SECOND AND THIRD ELECTRICAL CONDUCTORS ARRANGED IN SPACED RELATION AND AT OPPOSITE SIDES OF THE FIRST ELECTRICAL CONDUCTOR, A FIRST LAYER OF PIEZOELECTRIC CERAMIC MATERIAL OPERATIVELY CONNECTED BETWEEN THE FIRST AND SECOND CONDUCTORS, A SECOND LAYER OF A PIEZOELECTRIC CERAMIC MATERIAL OPERATIVELY CONNECTED BETWEEN THE FIRST AND THIRD CONDUCTORS, MEANS FOR APPLYING A FIRST VOLTAGE ACROSS THE FIRST AND SECOND ELECTRICAL CONDUCTORS TO CAUSE THE FIRST LAYER OF PIEZOELECTRIC CERAMIC MATERIAL TO EXPAND LENGTHWISE CAUSING THE FIRST CONDUCTOR TO BEND IN A FIRST SENSE TO AS TO CAUSE THE SECOND LAYER OF PIEZOELECTRIC CERAMIC MATERIAL TO CONTACT SO AS TO GENERATE A SECOND VOLTAGE BETWEEN THE FIRST AND THIRD CONDUCTORS, AND ELECTRICAL FEEDBACK CIRCUIT CONTROLLED BY SAID SECOND VOLTAGE FOR APPLYING A VOLTAGE ACROSS THE FIRST AND SECOND CONDUCTORS TO CAUSE AN EFFECTIVE OSCILLATION OF THE PLATE IN SAID FIRST SENSE, MEANS FOR SUPPORTING THE PLATE AT ONE EDGE THEREOF, AND A MASS MOUNTED AT AN OPPOSITE EDGE OF THE PLATE AND RESPONSIVE TO ACCELERATIONAL FORCES ACTING TRANSVERSE SAID OPPOSITE EDGE OF THE PLATE TO EXERT A MOMENT ON THE PLATE IN A SECOND SENSE FOR MODULATING THE FREQUENCY OF OSCILLATION OF THE PLATE.