<p>A rotary-to-linear mechanism including an elongate linearly-moveable first member having a longitudinal first axis, and rotatably-moveable second and third members. The second member is rotatably disposed about the first member and defines a second axis about which it is rotatable. The third member encircles the first axis and is operatively engaged with the first member. The third member is disposed in a central cavity of the second member and has an axial surface superposing a second member interior surface, the superposed surfaces each defining one of a pair of corresponding grooves each encircling the first and second axes.</p>
