Re: Automatic Wheelchair Turntable

[nobody@xxxxxxxxxxxx (Dave Houston)]

Or...

     http://www.manufacturingcenter.com/med/archives/0500/0500wlch.asp

nobody@xxxxxxxxxxxx (Dave Houston) wrote:

>I think your biggest problem will be to devise a thin turntable with a
>bearing that can handle the weight. A zillion (± a few slew) marbles
>sandwiched between two flat metal surfaces might work. For the drive,
>bicycle chain (industrial chain comes in a multitude of sizes) fastened to
>1/2 the circumference should be simple to work with.
>
>How is the chair secured when the van is in motion?
>
>"Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>
>>I just got my Dad a wheelchair van with an electric ramp but we've hit a
>>snag.  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.
>>
>>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.
>>
>>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.
>>
>>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, any suggestions, inputs, discussion or ideas where to post for good
>>feedback will be appreciated!
>>
>>(posted to:  comp.home.automation & alt.support.wheelchairs)