I am moderately disabled. I can walk but after about 10 minutes, I get fairly uncomfortable.
Grocery shopping is one of my most challenging tasks. Hoiking my mobility scooter out of my car's boot caused so much back pain for me that the scooter gets left behind and I just break up the shopping into a few small trips per week instead of once. The moby gets used for things like trips to museums, parks and other events where ambling about over a long period is required.
Most mobility scooters are far too capable for their own good. They are designed to safely transport a person on uneven footpath terrain between the shopper's house and the shops. Once in the shops though, big rubber tyres, heavy batteries, traction motors, staunch frame and a wide stance are largely unnecessary.
If the mobility scooter were pared down to the bare essentials necessary to move the shopper from car to where the trolleys are stored as well as push a loaded trolley around the shops, much smaller wheels, batteries and traction motors can be used.
A superlight folding mobility scooter which could fit in a duffel bag could be based around the steering components and 100mm urethane wheels used on a Razor type scooter. 200-350W of drive power, geared for a ~5km/h top speed on smooth, level surfaces would be sufficient. Running time would be limited to 2 hours at intermittent shop browsing and dawdling speeds. Should require only about 4-6 AH of batteries. Along with a tubular aluminum frame, This would keep total weight down to under 8kg.
The moby would have an adjustable clamp on its handlebars or steering tube to grip on to the push bar of any shopping trolley.
It must have a wide, comfortable seat with a small backrest which either folds or is detachable.
Because Australian shopping trolleys have 4-wheel steering, this moby will require 3 wheels (2 front, 1 rear) and possibly 4 to have a sufficient traction to create a fulcrum against which to force a fully laden (100kg) trolley go around corners. Aussie shoppers know how difficult 4 wheel steering is!
A version of this scooter for US type shopping carts, which steer only with the front wheels, could employ just two rear wheels (one driven) and be supported in the front by clamping on to the push bar of the shopping cart via a clamp fixed to a handlebar which is articulated via a steering head from the rest of the scooter frame to permit steering. This would sacrifice operation independent of a shopping trolley but would further reduce weight.
This idea is slightly more than half-baked. I’m very likely going to build a copy of this one. I have several junked Razor scooters and can buy a cordless electric drill for under $30 which will provide all of the drive and speed control for a working prototype.-- weezil, Dec 26 2004 Shopping trolley scooter http://www.esla.fi/eng/cpmain.htmlThis is without a motor, has a basket and seat for resting [Pellepeloton, Oct 25 2006] What about a unicycle? With a motor in the hub, the device ,ight be the size of an electronic keyboard; with a smaller wheel and overhead motor, maybe the size of a mailing tube. You could carry some clamps to lock the alignment of rear wheels on an australian cart.
Also, how do you fare with a bicycle? If, while seated, some gentle pedaling doesn't bother you, you can spare yourself the effort of lifting batteries out of the trunk.-- tiromancer, Dec 26 2004 Half, I've seen and ridden the motorized Razors. They are geared for too much speed and not enough torque to push a trolley. It's hard to adjust the drive ratio much as the 100mm wheels don't permit a larger wheel sprocket than standard to be fitted. Worse, the electric Razors are about $AUD350-400 around here (Sydney, Australia).
Tiromancer, I have considered clamps to lock the rear wheels in place on an Aussie trolley independent of this idea. Logged it on halfbakery today. Such would be a great help for those who have had knee problems.
You're quite right that clamping the rear wheels of an Aus/UK style trolley would obviate the need for front wheels on this moby and permit a unicycle design. A hub motor would be ideal in this application.
Can't pedal much, I'm afraid, but thanks for the suggestion. :)-- weezil, Dec 26 2004 half: Probably put a sprocket on it! Not terribly hard. There's a wheel in the garage with a sprocket on it already, in fact, from this project I did back in 2000: http://tinyurl.com/3tm83
*addendum*
Direct drive would probably be better. The cordless drill motor will already have a gear reduction unit. Will eliminate an adjustable motor mount and chain noise.
I'll run the axle in a pillow block and make up a flange hub to which I'll fix the wheel with 5x M5x30mm bolts.-- weezil, Dec 27 2004 //Once in the shops though, big rubber tyres, heavy batteries, traction motors, staunch frame and a wide stance are largely unnecessary.// I think for a person who can walk short distances, the scooter on my link is a good idea as it has no motor or batteries. I actually had one of those imported from Finland a while ago here in NZ after I had an accident and could not walk that well.
I had many people telling me that I should put a motor on it but I could not see why spoil an effective human powered vehicle design with ineffective or hevy motor?-- Pellepeloton, Oct 25 2006 random, halfbakery