All Terrain Wheelchair

[leroy157]

I started this project because I wanted to be more mobile now that my back and legs don’t work like they used to, and I have a shoestring budget.
My objectives are:
(1) Build a machine that will allow me to go places I can’t easily get to now.
(2) Top end speed of about 25 MPH.
(3) Travel on sand and grassy areas with minimal terrain damage.
(4) Easy to use, and get replacement parts for.
(5) Minimal maintenance and cost.
(6) Economical.
(7) Turn signals and lights with a strobe on top.
(8) Use in the winter.
Material used:
(1) ¾ inch steel pipe.
(2) Tecumseh 195 cc gasoline engine.
(3) Comet torque converter.
(4) 16 gauge steel.
(5) Differential rear drive assembly as seen in picture below.
(6) Tires 3 – 18 X 9.50 X 8.
As I progress on construction of my wheelchair I will upload new images. I also have some questions like does the rear end that I am using have a place to grease or lubricate it ?

Below is a drawing of my design. then a image of the drive assembly, and last my project. the frame today.
I welcome any comments you may have as this is my first project of this kind.

 

[fowler]

u could look at an axle from a ride on mower

it will make steering easy and be much kinda to your lawn as it wont cut it up like a live axle

 

[theo]

Have you thought about getting a old electric 3 wheel scooter? They are free or close to it. I took one of these and converted it to a 4 wheeler, with go kart spindles, Worked great but I lost the real tight turning radius the 3 wheel had. Last year the electrics packed in so I'm going to stuff in a clone.

 

[leroy157]

Thank you fowler and theo for your post on my project:
I did not realize a live axel would tear up turf on turns. I thought they were like a car rear end where the tire with the least traction would be the drive tire.
I looked for electric wheel scooters in this area on Craig’s list, I could find none. Originally I was going to go with an electric drive but, a gas driven machine will give me more power without sacrificing speed.

 

[wingnut]

Judging by the shape of the frame and your drawings, it looks to me like you're going for a tricycle design with a fairly high seating position. I think that would be prone to rolling over at 30mph. For a budget oriented build, I'd go with a used riding mower as a base. Used riding mowers are fairly cheap and (just as important) common. The only trick is how to do the clutch. I'm guessing that a spring loaded v-belt tensioner would not work for you. Perhaps you can mate the drive pulley on the motor to a centrifugal clutch...

 

[redsox985]

If budget wasn't an issue...

http://dsc.discovery.com/videos/howe-and-howe-tech-crazy-rip-chair-test.html

 

[fowler]

is there any reason u cant mount a tc horozontal under a mower

 

[redsox985]

Fowler, I don't think so... But I also don't think it's been done. Maybe Blaz will know. There may be an issue with the driver weight pack. I just don't know.

 

[theo]

I kind of like your design, I would go with 4 wheels and make it as wide as possible. Also the front end has to be beefed up somewhat.

 

[Doc Sprocket]

I'm going to be watching this build like a hawk!

I have some random thoughts, comments, questions, and answers. In nor particular order-

With the right tires and pressures, a "live" axle won't be too hard on the grass- however- I believe it will steer horribly! Only one front wheel will have a very difficult time resisting the two rear tires' desire to keep going straight. You seem to have a differential anyways. What's it from, and how wide is it? Yes, it will need lubrication in the centersection.

I agree with the others' thoughts that you really want to keep the speed reasonable. To that effect, you have the choice between gearing quite low and always staying that slow, or employing a multi-speed transmission, like from a riding mower. This would allow you reverse, as well as the ability to mechanically limit your speed in rough situations and avoid accidentally "flooring it".

You really have two options with the mower tranny. If you source a simple transmission, you can use your existing axle- but you might have to buy a vertical shaft engine. If you get a transaxle, you will be eliminating your existing axle, you'll probably still have to get a vertical shaft engine, but it will make for a narrower axle without mods, probably lighter, mower wheels will fit with no mods, etc. Often, cube for cube, vertical engines tend to be cheaper ('round here, anyway).

Some notes on definitions, to be clear- In our go kart community, we define "live axle" as- one axleshaft turning both wheels, with no differentiation. In the automotive world, "live axle" has nothing to do with differentiation, it refers to the actual axle beam- a straight axle that articulates as one unit (this includes non-driven axles, too- is a live axle. As opposed to independant suspension- so, if you have A-arms and coil springs, it is NOT a live axle, period.

It's too bad you're not closer. I have a Craftsman lawn tractor that would make the perfect donor for you that I would freely donate to you, just to see this project happen.

Your 3/4" steel pipe- do you mean "pipe" or tubing- there's a difference. Pipe has a thick wall and is heavier (typically) than tube, but is a pretty low-grade material in comparison to some tube.

 

[leroy157]

wheel chair more info

Thank you wingnut, redsox985, fowler, theo, and toystory 4wd:
Wingnut in response to your post: I can use my legs, and lift stuff as long as I don’t stand for more than 3 or 4 minutes at a time. The 30 MPH speed was wish full and I agree with you that 15 or 20 would be tops.
Redsox985: I went to the discovery site and believe me when I started my project I had some wild plans until I checked my budget, then reality grabbed me by the seat of my pants and I came up with my current plan.
Theo: I am going to beef up the front and also add suspension to the front wheel. The 4 wheel design is a good idea and I might have went with it but in researching my project on the internet all the stuff I seen was three wheel, and I read an article about the advantages and disadvantages of both.
toystory 4wd: The differential is from an old go kart, The frame is approx 32 inches and the axle is 42 ½ inches hub to hub. The large sprocket is 54 teeth and the small one is 12 teeth. I have not calculated the speed derived from this configuration, but will be doing so soon. You are right about low speed; I would rather have the extra power and a top speed of perhaps 7 MPH which would be fast for a wheelchair. I am currently looking to find a small transmission, or a garden tractor transmission or Trans axle. The ¾ inch tubing I am using came from the go kart frames, it is not thin wall and I noticed that as I weld it I have very little trouble with blowouts. Below is an image of the original cart.

 

[leroy157]

Origional frame

hopefully here is an image of old frame

 

[leroy157]

progress on my Wheelchair

I have just painted my wheelchair after extending the frame 12 inches under the seat brackets in order to make room for the seat and seat adjusters. I built my chair with brakes and throttle under floor board. In two days after paint is dry I will start assembling it. Length is 6 feet and width at back axel is 42 inches. Here are some pictures of it now. I work slow so it is taking longer than planed.

 

[lemegacool]

nice man keep up the good work!

 

[landuse]

It is looking good. Don't worry about how long it takes you to complete. The slower you go, the less problems you come up with.

 

[Doc Sprocket]

Frame looks awesome! Haste makes waste, so there's certainly nothing wrong with working at a slow-but-sure pace.