Device for the measurement of vibration displacement

Claim 1

A DEVICE FOR OBTAINING A D.C. VOLTAGE CORRESPONDING TO THE AMPLITUDE OF MOVEMENT OF A MEMBER HAVING A PERIODIC RECURRENT MOTION RELATIVELY TO A BASE, WHICH COMPRISES MEANS RESPONSIVE TO SAID MOTION FOR CREATING A PRIMARY VARIABLE VOLTAGE CURRENT WITH A FREQUENCY AND AMPLITUDE SIMILAR TO THE FREQUENCY AND AMPLITUDE OF SAID RELATIVE MOTION OF SAID MEMBER, A CIRCUIT, HAVING THEREIN MEANS RESPONSIVE TO SAID CREATED CURRENT FOR PRODUCING IN SAID CIRCUIT AN A.C. VOLTAGE, A LATERALLY INFLEXIBLE ELEMENT ARTICULATELY CONNECTED TO SAID MEMBER FOR MOVEMENT SYNCHRONOUSLY THEREWITH AND HAVING INERTIA MEANS SERVING BY ITS INERTIA AS A RELATIVELY FIXED CENTER ABOUT WHICH SAID ELEMENT MOVES IN SYNCHRONISM WITH SAID MEMBER, SWITCH MEANS IN SAID CIRCUIT AND OPERATED BY SAID ELEMENT FOR CREATING FROM SAID A.C. VOLTAGE A PULSATING D.C. VOLTAGE OF THE SAME AMPLITUDE AS SAID CREATED CURRENT, AND MEANS FOR FILTERING SAID PULSATING D.C. VOLTAGE TO MINIMIZE VOLTAGE FLUCTUATIONS THEREIN, WHEREBY SAID D.C. VOLTAGE CORRESPONDS TO THE AMPLITUDE OF MOVEMENT OF SAID MEMBER AND FURTHER MAY BE EMPLOYED FOR CONTROL OF THE MOVEMENT OF SAID MEMBER.