Monday, March 08, 2010

“I call it my little angel machine’’

As we search for ways of shrinking out collective "carbon footpring" a lot of attention is being focused on the transportation sector. And rightfully so. However, the emphasis on electric cars, scooters and foldable bicycles leaves out a segment of the population for whom these are not options.

When I was a civil engineering student at Tufts University many moons ago, I took a mechanical drawing class from a Professor Ernesto Blanco (he had the amazing ability to be able to draw a "perfect circle" freehand on the chalkboard). One of his inventions was a stair-climbing wheelchair. He was among the first designers that had the wheelchair occupant facing back towards the floor instead of having her/his back to the floor, in effect making the ascent a lot less scary. (GW)

MIT’s levered wheelchair extends freedom to Third World

By James F. Smith
Boston Globe
March 8, 2010

Some students go to MIT to plumb the mysteries of the atom, or of outer space, or to press the limits of computer science.

Amos Winter went another way: He’s trying to revolutionize the wheelchair. Specifically, he wants to make that most familiar aid to the disabled work in the Third World, where roads are bad, money tight, and the need immense.

A doctoral candidate in mechanical engineering, Winter calls his invention the Leveraged Freedom Chair - leveraged because it is powered by hand levers.

Abdullah Munish has another name for it. “I call it my little angel machine,’’ he said.

For years after he survived a car crash but lost the use of his legs, Munish struggled to move his wheelchair along the rutted, hilly roads of his hometown in Tanzania. Frustrated, he often just stayed indoors, and lost touch with friends and relatives.

Now, with the help of Winter’s invention, he has reclaimed his freedom and sense of connection. He can push himself up the hill to a neighborhood playing field where he can once again toss a ball around with friends. He can scoot along the gravel paths of Moshi to visit people again.

“We believers, we know that anything that changes your life in terms of mobility, that is something that comes from heaven,’’ said Munish. A 31-year-old wheelchair technician, he is one of six wheelchair users in Tanzania, Kenya, and Uganda who have been testing the prototype since August.

The genius of Winter’s wheelchair lies in the design of the long ratchet-like levers that power it. Hold them low, near the axle, and it goes fast. Hold them higher up, and it generates a lot of torque, making it possible to climb slowly but surely over rocks and up hills. In effect, you change gears by changing your body geometry.

That helps keep the wheelchair simple and inexpensive, and may make it affordable to some of the 20 million people who need wheelchairs in the developing world.

Winter said he hopes to get his lever-powered wheelchair patented and produced in substantial numbers - priced at about $200 each - within two years. He plans to test 30 more in Guatemala this summer, thanks to a $50,000 grant from the Inter-American Development Bank, and then conduct wider tests in India.

For Winter, a 30-year-old native of Chesterfield, N.H., wheelchairs are an accidental passion. After earning his master’s in mechanical engineering at MIT in 2005, he was foraging for a summer project that would let him be with his girlfriend in Tanzania. His MIT mentor, professor Amy Smith, suggested that he look into wheelchair needs there. He did, and came back obsessed with finding solutions to meet those needs.

In 2007, Winter founded an MIT laboratory - the M-Lab, for Mobility Lab - within Smith’s innovative laboratory, known for fostering simple, low-cost, and sustainable technology for the developing world. The M-Lab is a room crammed with welding gear and bins of cheap bicycle parts that Winter uses to make the lever-powered chair. His students are devising wheelchair innovations of their own. He also teaches an MIT course on wheelchair design for poorer countries and, like Smith, he is now dispatching protégés to developing countries.

Winter has riders test the wheelchair constantly to learn where it falls short, and then he tweaks the design. The feedback he got on his field visit in January is prompting two big changes: Winter is dropping the seat 4 inches, and making the chair 3 inches narrower so it can fit more easily through narrow doors in small homes.

He also works with wheelchair groups that have been active in the Third World for years, acknowledging that he freely borrows their ideas. And they are returning the compliment.

Ralf Hotchkiss, who founded and leads Whirlwind Wheelchair International, a pioneering global wheelchair design and advocacy group based in San Francisco, said of Winter: “He’s smart enough to trade ideas with all of us, to be basically open-source, and not just with us gringos, but with the many wheelchair inventors, traders, and vendors in developing countries.’’

Hotchkiss, who has been active in the field since the 1970s, noted that lever-powered wheelchairs have been around for more than 50 years, and a few companies market them now. But those often are very expensive - up to several thousand dollars - and use derailleurs or other gearing that is often ill-suited to tough conditions.

Designing the perfect wheelchair, he said, is a surprisingly complicated piece of human engineering.

“I used to work in aerospace,’’ Hotchkiss said. “That was simple. Wheelchair design is much more complicated.’’

Winter has been a quick study of those complexities. Each rider has unique needs in support, seating, and powering the device. Some chairs are better indoors, suitable for sitting on all day at work or at home. Others are good for longer-distance travel, such as hand-pedaled tricycles, but are too big for use in the home or office. He dreamed of a design that would suit all needs.

It was when he returned from his summer project in Tanzania that he had his epiphany. “The ‘a-ha moment’ was realizing that you can get a huge range of mechanical advantage by just grabbing the lever at different points. It’s so, so simple.’’

He demonstrated the chair in an alley outside the M-Lab in a bitter late-winter rain - speeding up by raising his hands on the levers as he pushed like a rower, and then braking by pulling the levers all the way back, like pedaling backward on a child’s bike. The levers connect to bike chains that turn the big wheels. For indoor use, the levers disconnect and stow in the chair.

Also essential to his design was that the chair could be easily manufactured, and even more easily repaired.

“If you can find a guy who can fix a bicycle, and they’re everywhere, he can fix this chair,’’ Winter said.

And as for building it: “Really, all you need is a hacksaw and a vise and a welder to make this thing.’’ He uses bike parts that can be purchased for as little as $1 per pound.

In Kenya, Peter Mbuguah, program manager for the Association for the Physically Disabled of Kenya, runs a workshop that assembles 500 wheelchairs a month, and said he has come to value the innovative and sensitive approach of Winter and his team. He underscored the critical importance of Winter’s work.

“When someone gets a wheelchair in Africa . . . you are giving a lease of life to someone, and you are entitling the whole family so they can concentrate on their own lives while the wheelchair user is able to generate some income on his own,’’ Mbuguah said.

In Kampala, the capital of Uganda, wheelchair user Fatuma Acan tested the Winter’s chair and found it very good for outdoor use, but she told him it was too big for indoors, and the seat was too high. Acan leads a nonprofit that produces the Roughrider wheelchair, a popular Third World design by Whirlwind, and is acting chairwoman of the Pan-African Wheelchair Association.

Acan said she found that by using the Leveraged Freedom Chair, “I can go longer distances than in my present chair, and I can go on rougher ground. I can visit my relatives in my village. I couldn’t do that in my own chair.’’

“This could change lives,’’ she said.


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