[coreyjon]

We had a scissor lift mechanism for "stack attack", and boy what a pain in the butt that was. Everything has to be kept in close in tolerance. We probably made the thing 3 times because of problems we had during manufacturing (student where just trying to get away with using the drill press - I was probably hogging the mill). We probably reassembled the thing a million times too, but it did work, and work well it did - until we smoked the fishy motors. we used a lead screw, and follower to actuate the mechanism, and there was so much torque at one point it bent the lead screw, and while it still worked, it went downhill from there. It's cool, if it doesn't have to go up very high, but its a heavy solution. Darn things weight a ton. Good Luck with your design. You could make he spans large, keeping the weight down, but then you would allow for a lot of flexing, and that could lead to disaster, with a lot of weight up high, it could shift easily, and cause the robot to tip on to its side.