<p>Actuator assemblies witha casing having an elongated body defining an interior with a longitudinal axis and an open end providing access to the interior, a main piston having at least a portion slidably received within the interior through the open end for sliding axial movement relative to the longitudinal axis between a retracted position and an extended position and a lock segment mounted to a portion of the main piston such that sliding movement of the lock segment moves the lock segment radially, relative to the longitudinal axis, between a locked position and an unlocked position.</p>
