Master of Science

Abstract

thesisThe drywall trade is the 4th most hazardous in the construction industry, with a worker injury rate 4 times that of the industry average. On a daily basis, workers are exposed to slips, falls, and falling objects, in addition to the large and awkward loads they must carry. Drywall sheets can weigh more than 100 lb and be catastrophic to the health of the installer's shoulders and lower back. For this study, an unpowered lift assist device was developed to carry the load of a drywall sheet during the installation process. The device takes the form of a polar robot similar to a camera jib and allows the installer to move sheets effortlessly through the workspace. Initial calculations indicated a nearly 63% reduced weight in the user's hands. A testing regimen was developed to simulate a drywall installer's most hazardous lifting motions. These lifting motions were repeated both with and without the device for comparison. During these lifting motions, test subjects were fitted with electromyography (EMG) sensors on four lumbar muscles to measure muscle activation. Mean, peak, and effort data for the lifting exercises were extracted and compared to the unassisted lift. Test data revealed overall muscle activation across all four muscle groups on both lifting motions was reduced by 69%. These data support the effectiveness of the device and warrant future development of such a device