Students Revamp Tractor for Use by Workers with Disabilities

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Students Revamp Tractor for Use by Workers with Disabilities

17 Jun 2005 Medical News Today

By installing a seat-lifting device and hand-operated driving

controls, undergraduate engineers at s Hopkins have transformed a

tractor to allow people with disabilities to help maintain the

grounds of a southern land state park.

The project resulted from a request from Donnie Hammett, ranger and

manager of the 596-acre Greenwell State Park in St. s County. In

keeping with the wishes of the Greenwell family, which donated part

of the property, the park has a special emphasis on outdoor

recreation for people with disabilities. When some of these users

offered to help with trail maintenance, hay rides and other chores,

Hammett obtained a federal grant to purchase a tractor, then adapt it

for use by people with disabilities.

After buying the tractor more than a year ago, Hammett could not find

a business willing to make the alterations, so he sought help from

the Baltimore-based Volunteers for Medical Engineering. Because of

successful collaborations with s Hopkins in the past, the VME

referred the tractor challenge to students in the two-semester

Engineering Design Project course offered by the Department of

Mechanical Engineering. A team of four undergraduates was assigned to

confer with the VME and people with disabilities in devising and

constructing modifications for the tractor.

The students needed to adapt the tractor so that people who are

paraplegic and others who use wheelchairs could access and operate

it. To address the first challenge, they installed a folding chair

and hydraulic lift system, powered by the tractor's diesel engine,

onto the side of the tractor. The user can start the engine with a

remote control, transfer to the lift and raise the seat via a hand

control. At cab level, the operator can fold down a ramp, grab onto

handholds and slide into the driver's seat. To enable a person who is

paraplegic to operate the tractor, the students modified an

electronic video game controller to serve as a hand-controlled

throttle. They also built a mechanical device that allows the driver

to depress the brake pedal with a hand. In addition, the controls

were set up so that a person without disabilities can disengage or by-

pass the hand controls and drive the tractor in a conventional

manner.

The student inventors, all seniors majoring in mechanical

engineering, were Forman, 22, of Denver, Colo.; Jon Haslanger,

22, of Chapel Hill, N.C.; Nalven, 21, of Potomac, Md.; and

Wolcott, 22, of Harding, Pa. Their modifications cost about

$10,000.

A few days before their graduation, the students gave the customized

tractor to Hammett, the park ranger who commissioned the

project. " This is going to offer some unique opportunities for people

in wheelchairs to work as interns, volunteers or even employees on

the park's trails, " he said. " You don't know what an esteem-builder

it's going to be. "

Hammett added, " We couldn't find anyone in the commercial sector to

take on this tractor project. I think it was a great learning

experience for the students. "

The project is not completely finished. The ranger said he plans to

replace the hydraulic system that powers the lift with an electric

motor that will not require the tractor's engine to be started before

the lift can be activated. He also wants to install sturdier, more

permanent grips in place of the rope handholds placed by the

students. Overall, he was pleased with their work. " I think it's 85

percent of the way there, " Hammett said. " I'm going to have someone

with disabilities riding on that tractor before the end of the

summer. "

The students enjoyed applying their engineering education to a real-

world project. " It was rewarding because you could see everything

you'd studied and worked on coming together, " Haslanger said.

Added Forman, " A project like this makes everything else worthwhile.

You get to apply everything you've learned and find out if this is

what you really want to do. It's a great exercise. "

Forman, Haslanger and Nalven plan to continue their studies in

graduate school. Wolcott has lined up a job with a private consulting

firm.

The modified tractor was one of nine s Hopkins projects completed

this year by undergraduates in the engineering design course. The

class is taught by F. Conn, a s Hopkins graduate with more

than 30 years of experience in public and private research and

development. Each team of three or four students, working within

budgets of up to $10,000, had to design a device, purchase or

fabricate the parts, and assemble the final product. Corporations,

government agencies and nonprofit groups provided the assignments and

funding. The course is traditionally a well-received, hands-on

engineering experience for s Hopkins undergraduates.

Color images and video of the researchers and their project

available; contact Phil Sneiderman.

s Hopkins University news releases can be found on the World Wide

Web at http://www.jhu.edu/news_info/news