Electronic force balancing device

Claim 1

A FORCE BALANCING DEVICE INCLUDING FIELD COIL MEANS; ARMATURE COIL MEANS; SAID ARMATURE COIL MEANS BEING DISPLACEABLE WITH RESPECT TO SAID FIELD COIL MEANS BY APPLICATION OF AN EXTERNALLY DEVELOPED FORCE; SAID FIELD COIL MEANS AND SAID ARMATURE COIL MEANS BEING INDUCTIVELY COUPLED WITH EACH OTHER SOLELY BY AN AIR PATH; FIRST CIRCUIT MEANS FOR SUPPLYING ONE OF SAID COIL MEANS WITH A STEADY DIRECT CURRENT; SECOND CIRCUIT MEANS FOR SUPPLYING THE OTHER OF SAID COIL MEANS WITH A VARIABLE DIRECT CURRENT; SAID FIRST CIRCUIT MEANS AND SAID SECOND CIRCUIT MEANS COOPERATING TO PRODUCE A VARIABLE MAGNETIC FIELD BETWEEN SAID FIELD COIL MEANS AND SAID ARMATURE COIL MEANS, SAID VARIABLE MAGNETIC FIELD HAVING A FORCE OPPOSING AXIAL DISPLACEMENT OF SAID ARMATURE COIL MEANS WITH RESPECT TO SAID FIELD COIL MEANS AS DEVELOPED BY SAID EXTERNAL FORCE; ELECTRONIC VALVE MEANS FOR ADJUSTING THE AMOUNT OF CURRENT SUPPLIED TO THE SAID OTHER OF SAID COIL MEANS BY SAID SECOND CIRCUIT MEANS; MEASURING MEANS INDICATING THE AMOUNT OF DIRECT CURRENT SUPPLIED TO THE SAID OTHER OF SAID COIL MEANS; MEANS FOR SUPPLYING AN ALTERNATING CURRENT TO ONE OF SAID COIL MEANS AND SERVING TO INDUCE AN ALTERNATING CURRENT IN THE OTHER OF SAID COIL MEANS; MEANS FOR SENSING THE ALTERNATING CURRENT INDUCED IN THE OTHER OF SAID COIL MEANS AND FOR PRODUCING A SIGNAL INDICATIVE OF THE DISPLACEMENT OF SAID ARMATURE COIL MEANS WITH RESPECT TO SAID FIELD COIL MEANS AS DEVELOPED BY SAID