Patent ID: 7307371

Claim:
An actuator comprising: a housing defining an interior volume; a primary driver comprising one of the group consisting of a piezoelectric element and a magnetostrictive element, said primary driver having first and second opposing ends and defining a longitudinal length between said first and second ends of said primary driver, said length of said primary driver being controllably variable; a reaction surface fixed relative to said housing, said reaction surface bearingly engaged with said first end of said primary driver; a bearing surface operably coupled to said second end of said primary driver, said bearing surface being longitudinally moveable relative to said housing together with said second end of said primary driver as said length of said primary driver is varied; a closed working chamber defined within said interior volume, a proximal portion of said working chamber being partially defined by said bearing surface wherein longitudinal movement of said bearing surface varies the volume of said working chamber, said working chamber defining a first cross sectional area oriented transverse to said longitudinal axis where said bearing surface is positionable in said proximal portion of said working chamber, said bearing surface having an effective cross sectional surface area substantially equal to said first cross sectional area; a fixed quantity of a substantially incompressible amplification medium, said amplification medium being disposed within said working chamber; an orifice defined by said housing, said orifice in communication with said working chamber and defining a second cross sectional area; and an actuating rod having a first end and an opposite second end and defining a rod axis therebetween, said rod extending through said orifice with said first end projecting outwardly of said housing and said second end being disposed within said working chamber in a distal portion of said working chamber, said distal portion of said working chamber defining a third cross sectional area transverse to said rod axis, said third cross sectional area being greater than second cross sectional area; and wherein said second cross sectional area is less than said first cross sectional area whereby the travel distance of said rod is amplified relative to the change in length of said primary driver; and wherein said second end of actuating rod disposed within said working chamber is surrounded by said incompressible amplification medium.