3339 BumbleB's Robot

Hi,
I heard from my team that many people were intrested how our climbing hooks are going up and down to pass the corner without any motor
http://www.youtube.com/watch?v=4oJm_2w1y94
So I will try to explain:
The hooks were connected on a pin to the conveyor so it could rotate up and down. We stretched a Latex Tubing that kept the hooks up. There was anther pin (just a long bolt) on the hooks that was connected to 2 spring on each side and when the hooks pushed down(by an mechanical stopper on the end of the conveyor) the pin entered a zone that locked it in place. To release the hooks in order to pass the corner we had U shaped parts that were in the right geometrical shape to push the pin from the locked zone in one direction but in the opposite direction of the conveyor the U shaped parts did nothing.
The U shaped parts can be seen in the video below (they are the lowest moving parts in the arm that can be seen in the video)
http://www.youtube.com/watch?v=Qc2aKDUUVe8

Yarden