Moving Dolly for stairs

Imagine a large dolly, capable of holding a refridgerator or vending machine. It has two wheels on either side of its base. The wheels are about 16" (small car rims) in diameter (perhaps replacable with different diameters to accomodate different stairs). The center few inches of the wheel are made up of the axle and hub assembly, it must be large to support the weight. The wheels consist of four or five reinforced (sturdy) metal spokes. As the wheels move forward, they lock, preventing backwards movement, but allowing forward, similar to a rachet. This ratchet feature should be able to be reversed, so you could pull something up and have somebody pushing from below. On the end of each spoke is a rubber, pivoting foot.The idea is that while one spoke's foot is in contact with a step on a stairway, force can be applied parellel to the stairway to move the next spoke to the next step. The next spoke's foot should be facing downward because they are weighted and freely pivoting. Depending on the number of spokes and the slope of the stairway, the spoke itself may get in the way of the step, or even over-reach it. The wheels would have to be easily removeable, maybe you just slip it on the axel and put in a pin. Different diameter wheels are available. I think that covers it, the frame would have to be light, but the locking mechanism, and wheels would have to be strong. Perhaps to make it mobile, (it wouldnt work as well on flat ground) the frame should be aluminum, or a similar light-weight metal. Later I realized you could just put ratcheted wheels on a normal dolly for the same effect... but this dolly would look much cooler.