Re: Automatic Wheelchair Turntable

["Burgerman" <burgerman@xxxxxxxxxxxx>]

"Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote in message
news:_rydnR8CpccKQ6beRVn-hw@xxxxxxxxxx
>I just got my Dad a wheelchair van with an electric ramp but we've hit a
> snag.

Does he drive it?
There isnt room for me to turn either, but I go in backwards, transfer to
the driving seat. And come out forwards.


There's not enough room to turn the wheelchair around inside the van.
> If he goes in forward, he has to come out backwards.
>
> I toyed with some automatic guidance systems to make sure the backup
> procedure didn't run him off the ramp, but I don't think that's a wise
> solution.

Do it the other way around, come out forwards?



> I decided that since there's almost a 4X4 foot flat area inside the van, I
> would take a 4x4 sheet of 3/4" plywood and make a turntable on the van
> floor.  When he transfers to the driver's seat, I want the turntable to
> automatically rotate 180 degrees to position the powerchair so that it
> will
> go down the ramp front first.
>
> I'm not sure how I would contstruct and power the turntable, however.
> It's
> got to be as thin as practical - there's very little extra headroom in
> these
> types of vans and it's got to have some sort of autodetection of exactly
> 180
> degrees - probably some sort of limit switch.

You will never make it thin enough as well as strong enough.  Its going to
be almost impossible to do.  A microswitch can turn it off at 180 degrees.


>
> Should I rout a channel in the outside of the circular-cut plywood panel
> to
> run a belt?  That why I could mount a motor in the corner and still have a
> pretty low overall height.  Sort of how some belt-driven record turntables
> are designed.  I could also cover the ends of the belt that are likely to
> drag loose seat belts into the works pretty thoroughly with a motor
> mounted
> in the corner.

You will need thicker plywood, anyway so use a smaller disk underneath, to
run the belt then the motor can go under the disk.

> Does anyone know if they make commerical turntables for this purpose?  As
> much research as we did on vans, lifts, ramps and options, it kind of
> floors
> me that we didn't realize there would be a "wrong way out" problem.  Just
> a
> reminder to always model things, even if they seem trivial.

Well I do this the other way around from a side door and its never been a
problem.

My van
http://www.powerchair-review.fsnet.co.uk/ricon-powerchair-wheelchair-van-lifts.htm


>
> Well, any suggestions, inputs, discussion or ideas where to post for good
> feedback will be appreciated!
>
> (posted to:  comp.home.automation & alt.support.wheelchairs)
>
> --
> Bobby G.
>
>
>