Abstract
Unintentional injuries are a leading cause of death in the United States, and they are
largely preventable. This is a problem, and it is the duty of engineers to work to stop these
injuries from happening. My technical research approaches this problem by creating a
safety device to prevent a specific unintentional injury. My STS research approaches this
problem by focusing on the accessibility of safety device design and distribution. Safety
devices are used to prevent unintentional injuries, but they are not always accessible to
every person that needs them. From an engineering perspective, the technical aspects of
designing safety devices are already very difficult. When an engineer is asked to not only
design a device to work as it is intended, but also to work for as many people as possible, a
complex task becomes even more complicated. Together, my STS and technical research
help to understand the social and technical problems a safety device engineer may face
and strategies to overcome those roadblocks.
The problem my technical research investigated was a specific unintentional injury,
run-over lawnmower accidents. Run-over accidents are a common cause of injury among
children, which is why a new safety device to prevent run-over lawnmower injury is needed.
How can we prevent lawnmower run-over injuries? My teammates and I researched run-over lawnmower accident statistics, and we determined that most injuries occur when the
lawnmower is moving forward, and that due to the properties of the lawnmower blade and
its speed, a realistic solution would prevent users appendages from going underneath the
lawnmower, instead of utilizing a method which focuses more on instantly stopping the
blade movement. For our proof-of-concept design, we built a system in which a
rectangular polycarbonate guard, placed on the front of the lawnmower blade housing,
was launched downward when a person was detected, preventing any body parts from
touching the blade. For our design, we used a mmWave sensor to detect if a person was in
front of the lawnmower, a solenoid latch to release the guard from its starting position
when a person was detected, a ball screw and stepper motor to raise the guard back to its
starting position after release, and a linear rail system to ensure all vertical guard travel
was fast and aligned. In the end, we were able to design a system that launched a guard
down when a person was detected. However, this proof-of-concept design would need
many improvements to be implemented on a real lawnmower. This project used many
cheap materials, and on a real lawnmower, an ideal solution would be much more robust.
The problem my STS research investigated was that safety devices are not always
equally accessible to all groups. This problem matters because from an Ethics of Care
standpoint, all safety device engineers must ensure that their products are accessible to
anyone who needs them. How can we make safety devices more accessible? To research
this problem, I analyzed previous methods safety device engineers and distributors have
used to make their devices more accessible, and I compiled a list of those methods which
can be used during future safety device development. Through this research, I found that
safety devices can first be made more accessible during the design phase with the use of
design methods like frugal engineering and finite element analysis. Furthermore, I found
that safety device engineers and distributors can also increase accessibility by dedicating
resources to increasing awareness of their product and to educating the public on how
their devices work. Finally, I found that working alongside users through codesign studies
can ensure that safety device companies fully understand the possible roadblocks to the
accessibility of their products.
The STS research was successful because it did find general strategies safety
device companies can use when developing their products to ensure they are accessible
to anyone who needs it. However, because this topic is broad, the strategies I discuss may
not work for every safety device. Future researchers should try to develop strategies for
increasing accessibility for specific safety devices or groups of safety devices. My
technical research was successful because it did successfully launch a guard downward
to create a barrier between the user and the lawnmower blade, preventing unintentional
injury. However, it is only a proof-of-concept prototype. Future researchers should run
tests in real outdoor conditions on real lawnmowers to ensure the device works for all
conditions, not just in the classroom.
Notes
School of Engineering and Applied Science
Bachelor of Science in Mechanical Engineering
Technical Advisor: Jason Forman
STS Advisor: Caitlin Wylie
Technical Team Members: Averell Stith, Jimmy Sejas, Mia Bonutti, Cole Smith, David Cuyuch, Richard Townsley, Vincent Hu
