Drive mechanism for a domestic vibration apparatus

A drive mechanism for a domestic vibration apparatus which comprises a transmission path to a load having a vibration part, the drive mechanism including a rotor shaft of a single-phase synchronous motor which drives a cam-and-follower mechanism having a mirror-symmetrical cam which converts the rotary motion produced by the motor into a vibratory motion, the rotor of the motor having a magnetic detent torque and a main direction of magnetization, the stator comprising exciter coils capable of generating a current, the stator having a main field direction and the longitudinal axis of the mirror-symmetrical cam extending at an angle to the main direction of magnetization of the rotor, and in which cam follower rollers are mounted on a driven end of a pivotal arm which is pivotal about a central pivotpoint and a vibratory part to be driven between reversal points is aranged on a driving end of said pivotal arm, the cam-follower rollers being constantly in rolling contact with the cam profile, wherein at the end of the transmission path which exhibits backlash a compensation spring (38) acts on the vibratory part (39) to urge one of the cam-follower rollers (31, 31a) against the cam (21), causing the position of the cam (21) relative to the direction of a magnetization of the rotor to be changed in such a way that in the case of a parallel orientation of the direction (22) of magnetization of the rotor and the main stator-field direction (16), the rotor (17) is forced out of a parallel position by means of the spring (38), into a positive direction, said positive direction being the direction in which a torque exerted on the rotor (17) by the stator current becomes zero before the magnetic detent torque has become zero when the stator coils (11, 11a) are not energized whereby the rotor is rotated into a stable rest position, the vibratory part (39) being situated in the proximity of a reversal point in the case of said parallel orientation.