Patent ID: 7554237

Claim:
A device ( 10 ) for generating forces that are variable and controllable in frequency and in amplitude, the device comprising: two unbalanced rotors ( 18 , 20 , 35 to 38 ) mounted coaxially in a casing ( 11 ), electromagnetic drive means for driving a first of the two rotors in rotation from the second of the two rotors such that the rotors rotate in opposite directions, brake means ( 43 to 45 ) for braking the second rotor ( 20 , 36 , 38 ) relative to the casing, means for controlling the speed of the rotors in order to maintain their absolute speeds substantially identical, and unbalance weights or flyweights ( 37 , 38 ) fitted to the rotors having the same static moment relative to the common axis of rotation and situated in or close to a common plane ( 39 ) that is orthogonal to one or both of the common axes of rotation ( 17 ) of the rotors.