Re: Automatic Wheelchair Turntable

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Thu, 29 Sep 2005 08:24:36 -0400, "Robert Green"
<ROBERT_GREEN1963@xxxxxxxxx> wrote in message
<_rydnR8CpccKQ6beRVn-hw@xxxxxxx>:

>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

A simple, compact approach would be a cable (or rope) and pulley/drum
system. Two cables each wrap 2/3 to 3/4 of circumference of the turntable.
One reversible or two uni-directional motors with drum -- or a hand pull --
turn the table. If friction/resistance of the table is made low enough, a
motor may be unnecessary.

Jist thots .. Marc
Marc_F_hult
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