US Patent 9763013 Moving magnet motors

An apparatus includes a load, a lever that is coupled to the load, and an electric motor that is coupled to the lever for driving the lever in oscillatory, rotary motion about a pivot axis. The electric motor includes an armature and a stator. The armature is coupled to the lever and includes a permanent magnet. The stator defines an air gap within which the armature is disposed. The stator is configured for creating magnetic flux across the air gap for the permanent magnet to interact with, thereby to drive motion of the load. The electric motor is configured such that substantially no detent forces (a/k/a cogging forces) are generated between the stator and the permanent magnet as the lever is driven by the motor.