Wheels seem to be the source of the greatest number of complaints about shopping carts. This invention features magnetically levitated spherical wheels to achieve friction-less omni-directional movement of the shopping cart.
The body frame is an ordinary shopping cart. Each wheel is spherical in shape, and contains an array of very strong permanent magnets, such as supermalloy, embedded in rubber balls. The magnets are arranged so that the entire outer surface of the wheel ball has the same polarity (N, for example).
The wheel case also contains an array of very strong permanent magnets. They are arranged so that the entire inner surface of the wheel case has the same polarity (N, for example). Thus, the magnetic repulsion between the wheel ball and the wheel case produces an air gap.
The wheel case has a hole on top so that a vertical rod can be inserted as a brake. The handle on the cart connected to the braking rod causes the brake to be applied while nobody is using the shopping cart. To move the shopping cart, one has to pull the brake lever, much like turning on an electric lawn mower.
The diagram shows the cross section of the wheel mechanism.
