[MrForbes]

We were having trouble with air consumption, so we thought about how to set up the cylinders so that they only need air applied on one end, the other end is open and gravity or some other part of the robot pushes it back to starting position.

On the jaw hinge...that looks like a tough problem, and it's hard to see enough detail of what you have now to help figure out different ways to do it. Maybe some close up pictures would help.