1) Your overall concept seems sound but you need to lay it all out to scale. 2x6 boards will not arrange themselves as you have shown.
2) You show a 4x4 block on the bottom corner. Is it stationary or does it move with the steps? Either way you will want a fixed stop at that point to absorb all the force. Do not plan on some kind of stop arrangement up near the hinge point. The closer the stop is to the hinge, the sooner it will fail.
3) Do not use a bolt as your hinge. You will want some kind of fixed pivot post with a bushing and a washer. Bolts and nuts make lousy pivots.