Patent ID: 8100346

Claim:
An actuator comprising: a casing; a piezoelectric element positionable in said casing; a multi-function spring also positionable in said casing and configured to apply a preloading force to said piezoelectric element; said multi-function spring including a one-piece spring body having a cavity formed therein in which the piezoelectric element is disposed, the one-piece spring body including a first segment having a piston configured to translate a motion of said piezoelectric element during operation of said actuator, a second segment having at least one flexural element and a third segment having a first set of threads configured to engage with a second set of threads of said actuator to stretch said second segment to a state corresponding to said preloading force; and a sealing member contacting the one-piece spring body and the casing, and forming a fluid seal between the one-piece spring body and the casing.