Abstract: Permanent magnets are employed to continually urge an rotatable element, such as an oscillating, motor-driven shaft toward a preselected position. When the torque from the motor becomes minimal or is removed, the shaft is returned to a pre-selected, or rest, position. A magnet is disposed on the rotatable shaft and two additional magnets, one disposed on each side of the first magnet, constantly repel it toward a location between the two additional magnets. Such constant repelling is useful in scanners, light-choppers and the like and helps to achieve a harmonic-like motion. In a laser scanner, when the shaft is returned to its preselected position, the radiation is undeflected from a preselected axis. The magnets take the place of springs and are superior to them in precision, length of life and in ease of installation and adjustment.