Our robot on our cart at West Michigan, with our very tall elevator, at full height there can be a foot of clearance between the ball and the overpass … although we will probably never need to go that high.
do you have any close up pictures of your system to lower/elevate the elevator? Are you using box tubing that telescopes out? Do you have good luck with not tipping?
We use box tubing with our own linear bearings. Each stage slides along the side of the previous stage. Every instance where two faces of metal rub against each other there is Teflon tape (not the stuff used in pneumatics), this is what allows the elevator to slide very smoothly. The elevator is also powered in both directions, so that we don’t have to wait for gravity to pull it down. So far we have not tipped while our elevator has been extended, but it is always a concern for an arm design. We try to concentrate our weight in the back and drive carefully when the elevator is extended. The elevators best features are its speed (less than 3 seconds to fully extend), and the fact that it is self leveling as it extends, to prevent binding. Here are a few more pictures:
http://img134.imageshack.us/img134/7199/img0517ro5.jpg
too bad you cant see the “xx” now because of the gripper:ahh:
Nice lift, it reminded me of this from 2005