Having been watching a lot of the Olympics, and in particular the most recent Paralympics, I naturally began to think about the problems facing wheelchair users in their daily navigation about a city.
Especially problematic is that old problem of stairs... which are everywhere of course; Train stations, Airports, Shopping malls, and a thousand other places besides.
But a line of thought occured to me which may present a possible range of solutions, and it came from the paralympic sports themselves... and an old black and white film.
I think it could be possible for a wheelchair to be rowed up stairs backward like a boat, with apparatus incorporated into the chair which would be a similar mechanism to a fitness rowing machine.
I am not knowledgable enough to be too specific about the engineering involved, but can describe the process I have in mind, and the general principles which some other enterprising student of engeneering and mechanics can have a go at building if they are so inclined...
To begin with, the chair is wheeled to the foot of the stairs in reverse, to adopt the same rowing attitude just as you would with a boat, and butt the wheels up to the first stair, which gives the mechanism and the force applied something to act against when completing each part of the process. Then, the "oars", or long metal levers (which may be the arms of the chair, with the capability to extend to give more leverage), are released from the locking mechanism, and locking the wheels from movement and pulled up to the start position in front of the chest as any rower would.
Now, the first movement in the sequence begins by pushing the oars away from the body, which firstly, causes the seat to slide back into the stairs to it's next position resting on the stair, and when this seat can go no further in the pushing motion transfers the force to pushin the seat back support (and therefore, the upper body of the occupant) back into the appropriate stair above the seat... this now means that there are two fixed points (under the backside, and another under the shoulder area of the occupant) for the occupant to work from when completing the last movement of this sequence... pulling the legs up the next stair through pulling back on the oars.
This means, that by having two of the three fixed points at any one time positioned on the stairs, only the weight of the one part of the body has to lifted by the force applied by the efforts of the rower, and not the whole body weight at once.
But now the sequence is in motion, the next set of movement s has to be different, as the first position of the first sequence is already placed on the step (the seat sliding action which set the sequences in motion) and cannot travel back, so it has to elevate the seat on this occasion by using the other two points to act against once thier next movements have taken place... so the sequence changes from:
seat, shoulders, legs,
shoulders, legs, seat,
or in positional terms from bottom to top:
...and so on, through the sequence till the top is reached, where I have not got a clue yet what happens then, or how to come back down!
But what I can say is that it is very similar to the action of a catapilar crawling, where it lifts it's middle section to shorten the distance between the front and back ends by dragging the back forward, then pushing the front off this newly seated back section, or how an able bodied person might go up the stairs backward by lifting the backside up the stairs as far as the propulsion off the feet would allow, then pulling up the legs from the backside, etc.
Also a problem I've not cracked yet is the encumberence of the wheels catching the stairs at the point where the riser meets the step top as you go... and haven't yet got any illustrations, but I hope I've described it sensibly enough to be understood.
But just like the film- Ice Cold In Alex- where they wind a huge truck up a sand dune using only a hand crank in the gear box.... if you apply time, and mechanical advantage, and suitable mechanisms (I think a ratchet system for each stroke of the movement both forward and back), you can in fact row a wheelchair up a flight of stairs!
But feel free to have a go and build one if you can, you might make someone's life, if not easier, at least a little more possible (power assisted version?).
...Oh, and of course, it depends on the disability of the user, and therefore their ability to use it.