Vibration generating device employing dynamically unbalanced electric motors

Claim 1

A VIBRATION GENERATOR COMPRISING, IN COMBINATION, A HOUSING INCLUDING A PLURALITY OF HOUSING SECTIONS CONGRUENTLY SUPERPOSED AT SEPARATION PLANES, THERE BEING A PAIR OF END SECTIONS AND AT LEAST ONE INTERMEDIATE SECTION; FASTENING MEANS ARRANGED TO DISENGAGEABLY CONNECT SAID END SECTIONS AND AT LEAST ONE INTERMEDIATE SECTION IN SUPERPOSED RELATION; THE ADJOINING EDGE SURFACES OF SAID HOUSING SECTIONS BEING FORMED WITH MATING SHAFT SEATING SURFACES ARRANGED TO RECEIVE AT LEAST ONE PAIR OF PARALLEL SHAFTS AT EACH SEPARATION PLANE; SHAFTS FIXEDLY SEATED IN EACH OF SEATING SURFACES; A PLURALITY OF STATOR CORES EACH FIXEDLY MOUNTED ON A RESPECTIVE SHAFT AND EACH HAVING A STATOR WINDING THEREON ARRANGED FOR CONNECTION TO A SOURCE OF A.C. ELECTRIC POTENTIAL; A PLURALITY OF ECCENTRIC ROTOR SHELLS EACH ROTATABLY MOUNTED ON A RESPECTIVE SHAFT AND EACH HAVING A ROTOR WINDING ON AN INNER SURFACE WHICH IS CONCENTRIC WITH THE ASSOCIATED STATOR, FOR ROTATION OF SAID SHELLS UPON ENERGIZATION OF THE ASSOCIATED STATOR WINDING; THE ECCENTRIC MASSES OF THE SHELLS OF EACH PAIR BEING ARRANGED IN DYNAMICALLY BALANCED OPPOSITION ALONG THE PLANE INCLUDING THE RESPECTIVE SHAFTS; AND GEARING INTERCONNECTING SAID SHELLS FOR CONJOINT SYNCHRONOUS ROTATION, WITH THE TWO SHELLS OF EACH PAIR ROTATING IN OPPOSITE DIRECTIONS; THE ANNULAR POSITIONS OF THE MAXIMUM ECCENTRICITIES OF ONE PAIR OF SHELLS BEING ANGULARLY OFFSET RELATIVE TO THE ANGULAR POSITIONS OF THE MAXIMUM ECCENTRICITIES OF AN ADJACENT PAIR OF SHELLS TO COMPENSATE FOR A CHANGE IN FREQUENCY OF THE SOURCE OF ELECTRIC POTENTIAL.