Posted: Feb 2, 2014 11:14 AM
Updated: Feb 2, 2014 11:15 AM
AMARILLO, Texas (AP) Four West Texas A&M University students armed with bungee cords, fishing line and a 3-D printer have helped design an affordable mechanical hand that could help thousands of children with a limb disorder.
In an engineering design class last semester, the team helped to improve the functionality of a hand prosthesis for the Texas Scottish Rite Hospital for Children in Dallas.
"It was a really humbling experience," said Alex Parra, who graduated in December and was one of the mechanical engineering majors who worked on the project.
"It helped us realize that we're blessed by having everything that we have," Parra told the Amarillo Globe-News (http://bit.ly/1jLD7M0).
The engineering team worked with 10-year-old Aly Hunt to modify a hand prosthesis to better meet her needs. Dwight Putnam, a prosthetist at the Scottish Rite Hospital, directed the students toward the initial design, which was designed by a South African prosthetist and placed online to download for free, he said.
Aly has a congenital defect in her left hand, but it hasn't slowed her down. With other prosthetic hands specifically geared to certain activities, she plays golf, tennis and the violin.
Some hand prosthetics the hospital makes are geared toward one activity, while others are multipurpose, Putnam said. The West Texas students' prosthetic is designed to pick up objects, such as a water bottle.
Aly said the West Texas students' prosthetic hand would look better in pink, but that was her only complaint.
"I like that when I use it, I can just pick things up very easily," Aly said.
Aly is the daughter of Emily Hunt, West Texas professor and head of the School of Engineering and Computer Sciences, who initially approached the Scottish Rite Hospital in search of potential prosthetics projects her students could develop.
The hospital works on about 400 prostheses each year, Putnam said, with about a quarter of them for upper extremities. The students' final design will eventually be shared with the hospital's research department for possible use in the future on a case by case basis, he said.
"It looks like we're well on our way for the hospital to have something in our library to help kids in the future," Putnam said.
West Texas senior Rikki Boelens said the design process was dynamic and involved a series of adjustments to create the final product.
"It was a really good way to see the cycle of having to continually redesign whatever you're doing," she said. "It was also a really good demonstration of how engineering is not just for stuff, but it can be used to help people."
The prosthetic hand is inexpensive in part because it has no electrical components. Instead, it relies on muscle movement. For example, when Aly bends her wrist, cables in the device tighten, causing the fingers to close, and when she straitens her wrist, the tension in the bungee cords is released and the fingers open, Boelens said.
"So, it's powered by her wrist motion, and it'll close and she'll be able to pick things up with it when she bends her wrist," she said.
The hand costs about $15, and it can be produced anywhere with a 3-D printer, said Emily Hunt.
"When (the Texas Scottish Rite Hospital) looks at helping thousands of kids with hand differences, being able to provide a tool like this for less than $15 a kid, that's really good for them, too," Hunt said.
The group adjusted the size of the fingers and the orientation of the thumb on the prosthesis to better resemble a typical hand, Boelens said, and the students also worked to make it more wearable.
"(Their design) was pretty bulky, heavy and hot, and so one of the things Aly mentioned was that she wanted something that didn't cover her arm completely, so we really had to work on finding a way to attach it with the least amount of material," Boelens said.
Parra was surprised by the amount of trial and error design and redesign necessary with the project.
"It was really crazy," he said. "Everything looked good on paper, but then when we actually put it together, it was hard to actually see it and for it to work, so we had to do a lot of changes and keep working on it."
Para learned that it's OK to ask for help while working on the project.
"Some people say that engineers act like they know it all, and we don't, so we have to ask different people for help and work in groups, because we can't do anything by ourselves," he said.
Information from: Amarillo Globe-News, http://www.amarillo.com,
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