http://www.valleytech.k12.ma.us/robo...1Robot2001.jpg
this has five stages half of the 1/8" cable is inside of the machine. This was a push pull system. 2 different cables. one to pull out and one to pull in. This is not hard to do at all. the hardest thing was to make the squares out of thin alum. we went 14' with this machine. we went 9' the year before.
we were only 17"when the machine was completely closed. this kept our center of gravity pretty low.