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Letting autoworkers sit while they reach into a car's interiorcould help prevent shoulder and back strain - but another solutionmight be to tilt the entire car so that workers can stand up. That's the finding of two recent studies, which tested two ways toprotect autoworkers from injury. Sitting on a cantilevered chair reduced the stress on the workers' backs and shoulders for three common installationtasks. But a different strategy - tilting a car sideways on acarriage so that workers could access the interior while standing -reduced the stress for nine different tasks. The chair study appears in the July issue of the journal Applied Ergonomics and the carriage study appears in a previous issue. The car carriage appears to be a better overall option forpreventing injuries, explained William Marras, professor and HondaEndowed Chair in the Department of Integrated Systems Engineeringat Ohio State University. "Under these conditions, if you can tilt the car, the chair becomesunnecessary," said Marras, who directs Ohio State's Center forOccupational Health in Automotive Manufacturing (COHAM), where thetests took place. Honda Motor Co. asked the COHAM team to test the commerciallyavailable chair as well as the car carrier, both of which arealready used in some of its plants and by other manufacturersaround the country. To use the chair, workers sit on a padded seat at the end of anL-shaped steel beam that is locked into a track above. The "L"slides back and forth as workers use their legs to pull the chairacross the floor and into the car. The researchers tested 10 men and women, five of whom wereexperienced autoworkers. The other five were college studentvolunteers, intended to represent first-time, untrainedautoworkers. They rode the chair into and out of a car frame whilethey tightened bolts and installed seat belts, shoulder slides,roof consoles, and dome lights. Wired with sensors to monitormuscle strain, the subjects performed these tasks over a simulatedeight-hour workday. In only three situations - installing the roof console andinsulation and tightening bolts in the center of the car - didsitting in the chair reduce loads on the spine and shoulder stress. The chair didn't help much when workers had to reach the sides orback of the car, either. For installation tasks at the edge of thevehicle, sitting in the chair reduced spine load but did nothing toreduce shoulder stress. "We thought that sitting down inside the car would make installingthe seatbelt easier, but it turned out that you'd need two righthands," said Sue Ferguson, senior research engineer at COHAM andlead author of the study. Originally, the cantilever chair came with a bucket seat thatprevented workers from moving freely. The researchers replaced itwith a flat seat and simplified the cantilever system overall. Thenew design was more practical than the original, and much lessexpensive: it cost $4,000 to build compared to the original's$100,000. In the car carriage study, the researchers had 12 people installequipment in a car's interior, underbody, and engine room whilestanding. They measured stresses on the people's bodies when thecar was tilted at different angles. Of nine different installation tasks, seven became much lessstrenuous when the car was tilted on its side 45 degrees. The othertwo showed similar improvements when the car was tilted completelysideways at 90 degrees. Because of the modification that the researchers made to the seatin the chair study, they began to think about ways to improve seatsin general. They are now working with a seat manufacturer todiscover more features that make a seat comfortable and functional. Meanwhile, Honda is using the Ohio State team's discoveries toimprove the ergonomics of their factories. In 2007, the companyreported that it was able to reduce injuries by 70 percent overfive years by adopting these strategies. Additional References Citations. The e-commerce company in China offers quality products such as Body Slimming Massager Manufacturer , Tens Massager, and more. For more , please visit Tens Unit Stimulator today!
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