[SonoranWraith]

Originally Posted by pugs

Or the tube holds the nut on the blind end of the "rod" and you spin the screw inside of it all

http://www.ultramotion.com/products/bug.php

This is the method I have seen on some german models. When it is really small and there are 2 cylinders (1 per side) the motor is in one and the limit switching is in the other. Never saw great pics on it but it was in the translated description.