An apparatus includes first and second sections supported for relative movement,
the first section having a plurality of first portions extending along respective
different axes, and the second section having approximately annular second portions
which each have a respective first portion extending movably therethrough to define
a pair. Each portion can generate a magnetic field, the magnetic field generated
by one of the portions of each pair being a function of an electrical signal. Interaction
of the magnetic fields generated by the portions of each pair urge movement of
the first portion relative to the second portion in a direction approximately along
the axis of the first portion.
