Digital force transducer

Claim 1

APPARATUS FOR MEASURING THE MAGNITUDE OF A FORCE APPLIED THERETO COMPRISING A LOAD RING, MEANS FOR APPLYING A RADIALLY DIRECTED FORCE TO THE LOAD RING FOR DEFORMING THE LOAD RING IN ACCORDANCE WITH THE MAGNITUDE OF THE FORCE APPLIED THERETO, A CONDENSER INCLUDING A SINGLE PLATE MOVABLE BETWEEN A PAIR OF PARALLEL PLATES, INSULATING MEANS CONNECTING THE CONDENSER TO THE LOAD RING BETWEEN THE POINTS OF APPLICATION OF THE FORCE THERETO FOR PRODUCING RELATIVE MOVEMENT BETWEEN THE PLATES ON DEFLECTION OF THE LOAD RING, A VARIABLE FREQUENCY OSCILLATOR HAVING A TANK CIRCUIT MEANS OF THE VARIABLE FREQUENCY OSCILLATOR WHEREBY THE FREQUENCY OF THE OSCILLATOR VARIES IN ACCORDANCE WITH THE MOVEMENT OF THE PLATES OF THE CAPACITOR DUE TO THE DEFORMATION OF THE LOAD RING, A STABLE OSCILLATOR FOR PRODUCING A FIXED FREQUENCY ELECTRICAL SIGNAL, A MIXER CONNECTED TO RECEIVE THE OUTPUT SIGNALS OF THE OSCILLATORS FOR MIXING THE ELECTRICAL SIGNALS FROM THE STABLE OSCILLATOR AND FROM THE VARIABLE FREQUENCY OSCILLATOR TO PROVIDE A DIFFERENCE FREQUENCY OUTPUT SIGNAL THE FREQUENCY OF WHICH IS DEPENDENT ON THE FORCE APPLIED TO THE LOAD RING, A BAND PAST FILTER TUNED TO PASS THE DIFFERENCE FREQUENCY OUTPUT OF THE MIXER, CONNECTED TO RECEIVE THE MIXER OUTPUT, A ZERO CROSS-OVER DETECTOR INCLUDING A GROUNDED DIODE FOR PROVIDING A UNIDIRECTIONAL ELECTRICAL SIGNAL AT A FREQUENCY EQUAL TO THE DIFFERENCE FREQUENCY CONNECTED TO RECEIVE THE OUTPUT OF THE FILTER, A GROUNDED EMITTER TRIGGER PULSE TRANSISTOR THE BASE OF WHICH IS CONNECTED TO RECEIVE THE UNIDIRECTIONAL ELECTRICAL SIGNAL THROUGH A RESISTOR, A SOURCE OF ELECTRICAL ENERGY CONNECTED TO THE COLLECTOR OF THE TRAN-