How can I create a wheelchair for a person with no arms?

In my engineering studies class I am required to design a wheelchair for a disabled person with a certain ailment, due to the fact that I am near the top of my class my disability is no arms! I just need ideas on how to create a steering system that has a turning circle of 75cm or less, as the driving and braking are easy.

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Madkins0077 years ago
Probably too late here, but I am a wheelchair tech. In the real world, a person who needs a wheelchair will have walking issues, so to assume full use of both legs is actually rather silly. In real life, a chair user with no arms gets a power chair with a head or breathing control system.

However, if I can assume full use of legs, I would use two pedals, working independently, to control the rear tires in the Irish Mail-type of linkage. You will get a good, but not tight, circle that way.

To make the circle tighter, rig a lever on each side that changes the direction the gears move the tires and position the lever so he can lean and activate it.

If you can use solenoids, etc., then rig the reversing up to a pneumatic control he breathes into
Tombini (author)  Madkins0077 years ago
Yep I have already made it with a direct drive to each of the wheels using pedals and straps to secure the feet.
It worked well and gave me an A for the asessment
Well, you didn't say no LEGS. In that case, build a unicycle and learn how to ride it (not as hard as it sounds). I was thinking, with a standard 4-wheeled chair it might be possible to steer using brakes. Attach a bicycle brake to each of the large wheels. Instead of standard levers to control these brakes, an easy-to-push pedal would be mounted on each side of the chair near the user's shoulders. That way they can lean on one pedal to brake one wheel or the other pedal to brake the other wheel. With one wheel stopped, the chair can then turn in a very small radius. If foot-pedal-power is permitted, that's easy to implement. If not, you have to think of something else that the user can do.
I ride unicycle, and I imagine its MUCH MUCH harder without arms.
True. More of an in-poor-taste joke... but hoping to start putting thinkers outside of boxes too.
Indeed - such as my other suggestion, take away the operator's guns. Tada, no arms.
ArcticChill7 years ago
A few concepts: 1: Have a pump type wheel-based-powered motion action (think a vacuum only it blows the wheels forward) and with body-motion-steering (moving body left and right; w/ free moving wheels) and finally when you lean back or stop "pedaling" the chair stops. 2: Like #1 it'll have pedals, just pedals. To turn you could have breaks on each wheel and two levers ( one on each or 1 side) and the could press on it to stop the chair (can also be used for #1). And lastly the breaks 2 concepts- Have a lever in the middle for both breaks or press down on both. Or- Make it so the pedals can only go forward (ie: stops when moved back) and makes the chair stop. (I've actually seen this on a few bikes. Additions: have reverse if pedals are moved backwards -emergency brake (no joke) -Help botton -Anything else you can think of Please comment back if you like my idea or have a question on how it could work (or if you'd like to make it an instructable)
Oh, or ask on my orangeboard and I'll answer on here.
frollard7 years ago
standard wheelchair - outfit with pulleys from 'where hands would go' on rear wheels to a set of independently rotating pedals that you strap your feet into - independent control of each wheel means you can drive in any direction and turn on a dime.
Electric wheelchair...steer with analog foot pedals...
Give the person a regular wheelchair - you dont need guns to use a wheelchair. "no arms"... hand that in, see what the prof thinks!
Tombini (author)  frollard7 years ago
Its not a concept, I have to actually construct and weld together a wheelchair and use it through a course! It cannot be electric powered, it must be manual and powered by a wheel (not by feet pushing along the ground) so the feet are used up in the pedalling and braking.
the pedal concept would work...as a real design.
gmxx7 years ago
tank drive... 1 wheel goes fwd, the other goes back. spins on a dime. you would need two swivel casters in addition to the drive wheels
Tombini (author)  gmxx7 years ago
but without it being electric how can I steer it?
gmxx Tombini7 years ago
Oh....hmmm... I would have each wheel controlled by a pedal by the foot. then put side mounted levers for brakes. With each wheel indepently controlled by the pedal sterring would be taken care of. the side mounted levers could be activated by the knees. Or you lock your legs out on the pedals so that your legs force the pedals not to move, which in turn locks out the wheels.
gmxx gmxx7 years ago
or you could use something like the http://en.wikipedia.org/wiki/Omni_wheel