Apparatus for demonstrating magnetic force

Abstract

An apparatus for demonstrating magnetic force comprises a plurality of disc-shaped rotors angularly displaced from each other on a common shaft and a number of magnets equispaced along the rims of the rotors. Stationary field magnets encircle the rotors in close proximity to the rotor magnets with like-poles of the rotor magnets and the field magnets facing each other. A high permeance magnetic shield is located in the air gap between each field magnet and the rotor to block opposing magnetic fluxes. Magnetic attraction between the rotor magnets and field magnets tend to rotate the rotor. In one embodiment, the shield at each field magnet is mounted on a pivot and is moved out of the air gap by arms attached to the rotor. The rotor magnets are first attracted to the magnetic shield, and, as a corresponding rotor and field magnet approach each other during rotation of the rotor, one of the arms causes the shield to pivot out of the gap to expose the rotor magnet to the field magnet. This creates a magnetic repulsion "kick" tending to further rotate the rotor. A weighted portion of the shield below the pivot, and an additional set of arms rotating with the rotor, automatically reposition the shield during rotation of the rotor. In another embodiment, stationary magnetic shielding located in the air gap is shaped to block only a portion of each field magnet from the gap. As the rotor is rotated toward the shielding by magnetic attraction, a "flywheel effect" causes the rotor magnet to swing past the shielding into view of the partially exposed field magnet to create the additional kick.

Dependencies are inferred from the claim text.