• Amos Winter, right, a PhD candidate in mechanical engineering, spent three weeks in January testing the Leveraged Freedom Chair in East Africa.

    Amos Winter, right, a PhD candidate in mechanical engineering, spent three weeks in January testing the Leveraged Freedom Chair in East Africa.

    Photo: Joseph Kisyoky

    Full Screen
  • Harrison O'Hanley ‘11 helps construct a prototype of the LFC.

    Harrison O'Hanley ‘11 helps construct a prototype of the LFC.

    Photo: Mario Bollini

    Full Screen
  • Winter interviews one of the six trial participants.

    Winter interviews one of the six trial participants.

    Photo: Joseph Kisyoky

    Full Screen
  • The Leveraged Freedom Chair

    The Leveraged Freedom Chair

    Photo courtesy of Amos Winter

    Full Screen

New wheelchair gets its first real-world test

Amos Winter, right, a PhD candidate in mechanical engineering, spent three weeks in January testing the Leveraged Freedom Chair in East Africa.

Grad student’s device aims to meet the needs of millions of people in the developing world.

The U.N. Development Programme estimates that less than 1 percent of the need for wheelchairs in developing countries is met by local production, partly because small workshops can’t exploit economies of scale to be profitable. Moreover, the wheelchairs that are available aren’t designed for people who must push themselves over rough roads and muddy walking paths often encountered in the Third World. As a result, millions of people must rely on others to carry them or be stranded inside their homes.

What is needed is an affordable device that can carry users comfortably and efficiently off-road, but is also small and maneuverable enough to use indoors. Amos Winter, a PhD candidate in mechanical engineering, along with a team of undergraduates and international design collaborators, has designed such a device, which he describes as performing like a combination of a desk chair and a mountain bike — "something you can comfortably sit in all day and maneuver around the office, but also use to efficiently commute to and from work.” Constructed from widely available, cheap bicycle parts, the Leveraged Freedom Chair (LFC) features two large levers attached to a bicycle drivetrain that helps the chair power through mud and over rocky paths.

Winter recently returned from East Africa, where he spent three weeks in January surveying six disabled people who had tested prototypes of the LFC. Using feedback from the four-month trial, as well as a $50,000 grant he recently received from the Inter-American Development Bank (IADB), Winter is currently tweaking the LFC design in anticipation of advancing it to large-scale production, which would provide local manufacturers with the tools to produce 500 to 1,000 units per month.

According to the U.S. Agency for International Development, 20 million people in developing countries require wheelchairs; Winter estimates that 70 percent of those people live in rural areas where regular wheelchairs simply don’t work. He has been studying the problem of wheelchair production in Third World countries since the summer of 2005, when he traveled to Tanzania on a public-service fellowship and saw firsthand how wheelchairs that rely on hand-rim propulsion are too difficult to use on rough terrain and for long-distance travel. He also learned that hand-powered tricycles are too big to use indoors and usually have only one gear. His solution “for people who grew up in a village where they were literally dragging themselves to school” is the LFC.

By pushing two levers located on each side of the LFC, a user can change mechanical advantage by simply moving hand position in order to go fast on flat ground or to produce enough torque to travel over sand or through mud. The removable levers hook into a bicycle drivetrain that has been converted to work on a wheelchair and is made entirely of bicycle parts that can be found throughout the developing world. This means that the LFC can be made and repaired anywhere one has access to a hacksaw, welder, drill and vice.

Freedom to move around

Winter has been developing the design ever since the concept won the MIT IDEAS Competition in 2008, partly in conjunction with a wheelchair design class he teaches at MIT’s Mobility Lab. Winter founded this lab in 2007 so MIT students could collaborate with local manufacturers and experts from the developed world to produce mobility aid technologies.

One of those experts is Matt McCambridge, a designer for Whirlwind Wheelchair International, a San Francisco-based nonprofit that produces durable, low-cost wheelchairs in developing countries.

McCambridge likes the simplicity of the LFC design, but says he has been most impressed with the intentionally slow, methodical implementation of the LFC. He praised Winter for conducting user testing early, “rather than inventing something in the lab, then using donor money to make thousands of them and forcing them on disabled people who really have no option but to smile and say, ‘thank you.’ ” McCambridge believes that Winter’s process should produce solid results that grow slowly.

The implementation began last summer, when Winter launched his first trial in East Africa with collaboration from the Association for the Physically Disabled of Kenya. He and Mario Bollini ‘09, Danielle DeLatte ‘11, Benjamin Judge ‘11 and Harrison O’Hanley ‘11, spent a month in Kenya building eight prototypes of the LFC. Each chair cost slightly less than $200 to make, which Winter said is roughly the price of a regular wheelchair in Kenya. Weighing about 65 pounds, or five to 10 pounds more than a regular wheelchair, the LFC was customized for the trial participants, who range in age and live near varied terrain in Kenya, Tanzania and Uganda. Winter returned to Africa with MIT senior Tish Scolnik four months later to interview the participants and test the efficiency of the LFC for each user.

What they learned from the “phenomenal feedback” is that although the LFC is more efficient than a regular wheelchair for plowing through mud and over big stones, it is still too wide and heavy. Winter will make the chair lighter by lowering the seat four inches and shifting the wheels back two inches, which will eliminate the need for the bulky mounting brackets that are currently used to attach the rear wheels to the chair.

‘My little angel machine’

In addition to reducing the width and weight, Winter will focus on improving the LFC for indoor use so that it functions just as well as a normal wheelchair when the levers are removed. He uses the desk chair/mountain bike analogy to describe how the LFC is intended to be used all day. Although someone might spend many hours each day sitting in a desk chair, it would be horrible to use that chair to commute to work, especially if the commute involved dirt roads. Similarly, while the mountain bike would be great for the commute, it would be awkward and uncomfortable to sit on all day at the office. “What we have now is an LFC that is great off-road and is comfortable to sit on, but is still too big to comfortably use indoors,” Winter said.

With the trial results, guidance from manufacturing collaborators and help from a group from his design class, Winter will use the IADB grant to design a new prototype and produce about 30 chairs for another trial that will begin in August in Guatemala. One crucial goal of the trip is to develop the manufacturing equipment that will be used to build the chairs for large-scale production, which Winter hopes will begin in 2011.

Until then, he continues to review the feedback from the East African users, including Abdullah Munish, a Tanzanian spinal injury survivor who lives in a hilly town with rough roads and who has tested various wheelchairs over the past decade. Munish said that in terms of capability and functionality, the LFC is “number one” compared to other wheelchairs.

“It is strong and stable in African terrain, and you can travel long distances and uphill without using too much energy,” he told Winter. “I would say that we have [a] life saver … I just call it my little angel machine.”

Topics: In the world, Innovation and Entrepreneurship (I&E), Global, Mechanical engineering, Students, Volunteering, outreach, public service, Wheelchair technology


I think this wheelchair is really appreciable & amazing Invention for handicap students who actually want to see world but they can't.

Ok, this looks like a great idea, how about releasing the design to us functionally poor wheelchair users a little closer to home who life in adverse rural conditions, but can't get afford an off road chair. Like... me.... in the snow in Northern Ontario province, in Canada. I have a welder, a hacksaw, a vise, and 200 dollars. I'm absolutely positive that there are rural Americans under similar difficulties. Perhaps the design will be licensed for profit in the first world, to pay for prototypes on the other side of the world. Yay for Africans, not so good for the rest of us. (Why does charity have to start so far from home)?

It is gratifying to see the results of good product design work that aims to improve the quality of life for wheelchair users in developing countries. In our product design course (as part of our BASC Design and Manufacturing programme at the University of Trinidad and Tobago), students recently came up with a low cost wheelchair modification using handles for propulsion after working with users who had reduced arm function

The benefits of a user-centred design process cannot be overstated.

I am a quad living in kenya but broke my neck whilst in the US so have a quickie chair which I can use to get about practically everywhere. The cost of the chairs is what holds back a lot of people who are trying against very big odds to get on with life after a SCI in Kenya. Wanted to know if APDK (Association of People with Disabilities in Kenya) would have a prototype or whether the 6 that were tried are still in Tanzania?

Hello, I write on behalf of my husband. We own a farm in eastern Montana. My husband lambs 80 ewes each spring from a wheelchair. We are constantly trying new ways to cope with the mud and manuevering in and out of small stahls to take care of the animals. We recently purchased a Renegade Wheelchair and quickly found it would not work in his application. We have been working with a mechanical engineer to adapt the technology to make his struggle easier. If you ever need someone to test your design in our setting please contact us. We would accomodate any way we can. Thank you for what you are doing.

I would like to touch base with those that have given comments thus far, I will be continuing work on the chairs U.S. development while some of the group is working in Guatemala. Input is very welcome to provide direction for the chair in the coming weeks. Please email benj_19 at mit dot edu

People with low arm strength would benefit from lever chair. Some people now drag themselves with their feet. Others must be pushed. An indoor/outdoor chair that is lighter and more compact, and could be put in a car, would be very useful here in senior developments and private homes.

We live in a senior community in Atlanta, GA, where a number of people could use the leveraged freedom chair right now. How do we get one here to try out?

Larry Schnee

I agree with Bobby ironsights

how bout closer to home as well. I live in Alaska and am researching all terrain wheel chairs for a rural treatment strategies class at University of Alaska. Mobility for individuals in wheel chairs in rural Alaska is a huge problem. Most people in rural Alaska live in poverty and maintaining a traditional subsistence lifestyle or even just getting around town can be next to impossible most of the year by wheel chair. I came across the Renegade wheel chair which would be awesome for this purpose. I am having a difficult time finding funding for such a large purpose, it is around 5000. There is assistance available for veterans but, that seems to be about it. There is a great need in rural Alaska for affordable all terrain wheel chairs and adaptive equipment. So often third world problems on our own continent are overlooked especially when it is in indigenous communities.

I agree with you. This a definite problem in rural Alaska. The technology exists but, the funding to provide this type of mobility to the poorest poor in the U.S. does not.

I live in the United states and, I am disabled and can see how this chair could change life for someone like me. I live alone and can transfer myself in and out of a chair. I think one of the things I see here that makes me excited is that this chair would be easier to transport then an electric chair and still allow the user to mobile himself without bring pushed in all terrain. I know this could benefit my life. I can not see where funding would be a problem when medicaid and medicare can pay 13000.00 dollars for an electric. I would rather have a chair like this that is more portable. I know I have a issue with my shoulder but if used when needed, this could help with traveling and working to have a chair like this. I am poor but even I can save $200.00 dollars with time for something like this that would change my life in the future. I commend you from the bottom of my heart for making such a wonderful wheel chair. I just have one thing I need to know is when are they going to be available to buy? Where can I buy one?

Back to the top