Patent ID: 7400080

Claim:
An actuator comprising: a tubular portion extending in a longitudinal direction, the tubular portion comprising a body of an elastomeric material arranged between two electrodes, wherein any line of symmetry extending between two opposite points on a periphery in a cross-section perpendicular to the longitudinal direction has a length which is different from any other such line of symmetry, wherein the tubular portion is formed by rolling up a sheet comprising at least two elements each comprising a body of an elastomeric material and an electrode attached to a first surface thereof, wherein deformation of the body is restricted in a first direction and supported in a another, second, direction, wherein the sheet comprises includes: an element of a first type comprising a conductive terminal of a first type being in electrical contact with the electrode of the element an element of a second type comprising a conductive terminal of a second type being in electrical contact with the electrode of the element, and wherein the conductive terminal of the first type is electrically isolated from the conductive terminal of the second type when the elements are stacked.