[davidgbevan]

my name is david bevan, for my final year at university i decided to redesign the wheelchair. i have included four images showing the design. this design is for the urban enviroment for everyday use. simple as for the working environment or popping down to the corner shop for some food.

i have done finite element analysis testing onto the frame to see how 200pounds would affect the frame. slight deformation to the frame but nothing serious. the method for how the frame will be stuck together is Mig Welding. the welding material is stronger than the frame should hold in theory. i'm in the process of building an ergonomic rig. this rig will ensure in pratice the frame is strong enough to hold someone.

i have angled the wheels in slightly to improve the frame strength by spreading the weight load across the rear 24" wheels.

making the wheelchair a rigid frame instead of a folding frame is so i can work more towards the ergonomics of the disabled vehicle.

but if you could have a look at the pictures i have posted with this thread and tell me what you think. they are medium test renders. i have still got some slightly detailing left to do on the design but otherwise its pretty much finished for my major project. any comments would be helpful towards my final year design report.

thank you for reading.

David

This post has been edited by davidgbevan: 27 March 2008 - 01:25 PM

[KarenFerguson]

The design is very cool looking, however, practicality wise it's a bit off. For me, I'd totally hit my hand on those arm rests - they seem to be in the way of the wheels. Also, the fact that there isn't a cushion isn't great for pressure sores or for that matter comfort in general.

These are just my initial impressions of the chair. Your design is very innovative. What program did you use to create the chair? 3d max perhaps? I haven't used that program in a few years, but I had such a fun time with it!

[Doppleganger]

Hi David,

What is your target market for this design of chair? as a chair to be pushed (like in hospitals) or for the independent user.

Whilst its a very fine and open design (good for getting in the car with quick-release wheels) it would not be suitable for many independent user due to:

1) The size of the front wheels is little large as when they turn they could hit the back of the users heel.
2) The fix arms of the chair would prevent a side transfer and get in the way when pushing.
3) Non-adjustment of the sitting position would also produce an uncomfortable ride, unless the seat was molded to the user profile (like in an F1 car)
4) lack of any comfort - seat & back cushions.
5) Brakes, although not very stylish they come in useful at times.

Hope these tips help.

This post has been edited by Doppleganger: 21 March 2008 - 03:46 PM

[davidgbevan]

hey karen ferguson

thanks for your input.

as you said about the cushion, ive been working on the design for padding for awhile. i have posted my pictures on acouple of wheelchair forums, and that tends to be the main factor to address.

i used an ergonomic 95th and 95 percentile male and female to ensure that the user could sit in the seat and reach the wheels without any problems. i had to write a simulation and analysis paper on my wheelchair, i have done quite alot of adjustments. if you give me your e-mail i can send you some pictures with ergonomic men within the image so you can see.


the software i use is

autodesk studiotools 2008
autodesk image stuudio 3.0
Ideas Nx 12
Solidworks 2007

thanks

[davidgbevan]

hi Doppleganger

this wheelchair has been design for the independent user. but comes with a handle so if help is required it can be. based in a city environment.

talking about the points you addressed early today. thanks btw. very helpful and good questions to answer.

1) the size of the 6" castor wheels have the right amount of distance to not hit the heel.
2) the simulation and analysis testing enabled me to find out how much space and what entrapment areas i would come across when working out the armrest. i think i spent quite alot of time working out the shape of the armrest. if your interested in seeing more pictures of it, that would be cool. i can post alot more if you wish. hopefully start of next month i am going to be building an ergonomic test rigid so i can find out if i have worked it out. fingers crossed really.

3) with the seat. i'm just modelling the padding for the back of the seat. i have been looking into breathable polymer mesh material. which has the same affect as an f1 car seat. i did have a crazy idea orginally for the wheelchair seat but i dont have enough time to research it and model it. i think after i have finished my design for the deadline. i'm going to put in alot of extra works and get a more ergonomicly designed seat. i would like to have a chat with anyone who wants to know about the modular system i have created.


4) i kinda tired that point into three.

5)72% of wheelchair users use there index finger and thumb to stop the wheelchair. they dont even use the break. the whole point of my wheelchair is to come up with a wheelchair do reduce parts, reduce cost and be a fresh radical design. at the moment alot of wheelchairs do look bulky, heavy and industrial.. i dont know what your view is on the current design influence of the wheelchairs on the market. They havent developmented at all

i think the cad renders havent quite given you a really good idea how the size and how easy it is. i have worked it all out on screen. i think i'll post some images with ergonomic man within the wheelchair so you can get a better idea and help me develop the concept.

i'm disabled, i'm born missing my right lower hand. so i find it difficult to use a manual wheelchair. ive got one at uni.. its quite hard to push so i get my fellow designers to push it around so i can get a good idea how it works.

thank you.

[silone74]

Hi the design looks cool but as said how would i get into it if the arm rests are fixed into that position?? I cant stand and sit from the front i need to transfer from the side of the chair and looking at your design the arm rests are fixed and go too far forward to not allow any one to get in the chair from the side, as for brakes on a chair they are not used to stop you but to lock the wheels while getting in and ont of it so the chair does not move away from you they are wheel locks not brakes. Looks nice but i dont think it would be a practical every day chair that could handle the abuse that a chair gets each day just going down to the shops,does it have side way strength so as not to buckle when turning i dont see any rigid support to stop this. Making a light chair is great but not at the cost of usability my chair is titanium very light strong and is minimum in the ammount of tubing with no arm rests but side guards to stop cloths rubing on the tyres these are removable to gain access to transfer on and off of the chair with ease.



Silone74

[edlee]

First, let me say that it is a beautiful piece of work.

Now the bad stuff,,,,As stated above, the arm rests will make it impossible for most users to transfer onto the chair. That alone would keep me out of it.

The foot rest needs to have some way of keeping the feet on it . A wider flat spot and possibly a strap of some kind.

Most of us who use these chairs lack feeling, circulation, and/or the ability to heal quickly, so the use of specialized seating pad/cushions is mandatory. Shaping the seat to fit the " average" butt won't work as all our butts are different.

I don't know if any of this is of help, but at least you will have heard the obvious (to us) problems stated before you have to defend them to your professors.
ed

[MAMA]

It looks absolutely artistic.....but a few questions or I guess just general input...

~ My husband drives himself in his own truck so how would this be for someone who has to put a wheelchair into a pickup without assistance?

~ How heavy is the chair going to be in final product....

~ Seating..yes you've already heard about it lol

~ Foot rest....most people in chairs require a strap or a wider rest for their feet as they have no control over keeping them on a foot rest

~ How is it for maneuvering? My husband gets around very well, doing wheelies to turn and get through doors etc....how easy would this be in this chair?

Great work and it looks beautiful!

[macthefox]

Hi David - as you are finding out it is not possible to construct a single chair that is ideal or in fact in some cases even usable by all. To me this illustrates two things – you are trying to design and construct it and are asking the people who will use it for their input and those of us that are users are being supportive and constructive in our feedback – that should mean that the end product will surely be greatly improved as a result and as in the commercial world variations will be included for alternative groups. What a change from manufacturing it first, then marketing it, then finding that you got it wrong – how often do we say – why not ask consult the users first.
Look at all the comments, prioritise, look at your options and go for it, you will never keep everybody happy-you just do your best
Good luck
Mac

[maxsound]

hey i would love to see the pics it sound good by the response youve got

you all see them? i dont. how do i see the pics?

[Yong]

maxsound, on Apr 21 2008, 08:06 AM, said:

hey i would love to see the pics it sound good by the response youve got

you all see them? i dont. how do i see the pics?

Same here. I see no pictures.

[silone74]

Looks like he removed the pic from the original post? it was there to start with.


Silone74