Apparatus for transmitting motion to a moveable body comprising: a first bar having ends; two articulated arms, each comprising first and second arms connected at a joint having an axis about which the first and second arms rotate, wherein the first arms are of equal length, the second arms are of equal length and the second arm of each articulated arm is connected to a different end of the bar at a joint having an axis about which second arm and bar rotate; a mount connected to the first arm of each articulated arm at a joint having an axis about which first arm rotates; a second bar coupledto each articulated arm at a joint having an axis about which the second bar rotates; and a piezoelectric motor coupled to the first bar controllable to apply a force selectively in either direction along the bar's length; wherein, the joints are configured so that all the axes are substantially parallel and the first arms are parallel and the second arms are parallel for all rotations about the axes.