Patent ID: 7298068

Claim:
An actuator comprising an inner sliding cylinder and an outer cylinder in which the said sliding cylinder is pre-stressed, with either the outer cylinder or the sliding cylinder being in a material with a negative or approximately zero thermal expansion coefficient, with the other cylinder having a positive thermal expansion coefficient or one that is approximately zero, where the actuator also includes a linear piston in an active material, with a multiplicity of sections capable of being controlled so as to be expanded in a manner that causes it to jam in the sliding cylinder and/or to be elongated within the sliding cylinder in such a manner that the piston moves by dry friction axially in the sliding cylinder, wherein the material of the cylinder with a negative or approximately zero thermal expansion coefficient is one of the following materials: γ-ZrMo 2 O 8 in cubic structure, Zr 2 WP 2 O 12, a silicious faujasite, Lu 2 (WO 4 ) 3 , ZrW 2 O 8 in cubic phase, that has nanograins whose size is approximately between 10 nm and 75 nm, or any possible combination of these materials.