Image Number 4 for United States Patent #5742113.
A device for the tilt-free movement of one solid body with respect to a reference body is achieved by fixing first and second plates, illustratively with large central apertures, in spaced-apart parallel planes with cylindrical flexure tubes sandwich therebetween. Each of the flexure tubes includes an upstanding piezoelectric or electro-strictive cylinder therewithin. The flexure tubes are aligned radially from the common central axis of the plates and are conveniently at 120 degree angles with respect to one another to achieve symmetry. The piezoelectric cylinders are responsive to like voltage signals to expand or contract in a manner to expand or contract the diameter of the flexure tube to produce the desired tilt-free movement of one plate with respect to the other. The flexure tubes, although small, are very strong due to the cylindrical geometry and yet, are responsive to relatively low signal levels for producing the requisite expansion and contraction.