drive device whose theoretical structure is shown in fig1 and 2 comprises a drive shaft 10 that is mounted to rotate about an axis 12 in the direction indicated by arrow f and in the opposite direction the drive shaft is intended to impart oscillating motion about an axis 16 orthogonal to the axis 12 to a driven member 14 the drive member 14 is separated from the shaft 10 by a thin wall 18 of non magnetic material to do this the drive shaft 10 carries a magnet 20 which in the embodiment shown is in the form of an axially magnetized peg offset from the axis pointing towards the driven member and fixed to a turntable 22 which is secured to the shaft 10 the magnet 20 has circular motion imparted thereto when the shaft 10 rotates and it is advantageously placed in such a manner that its axis intersects the axis of rotation 12 at the point where it intersects the oscillation axis of rotation 16 or in the vicinity of said point of intersection the driven member shown comprises a body 24 fitted with two stub axles 26 that rotate in bearings not shown that define the oscillation axis 16 the body 24 carries a magnet 28 designed to move following the magnet 20 in such a manner as to maintain a minimum gap between them to do this the midplane of the magnet 28 which must remain substantially in alignment with the midplane of the magnet 20 has a shape that is circular or nearly circular in the example shown in fig2 the magnet 28 is in the.