July 2000 - Occupational Health and Safety

A War on Weight & Vibration
Workers appreciate the intervention that brought vibration-damping tools, tool balancers, and lift tables to their line.
by Jerry Laws

Sometimes the winning strategy in an ergonomics project is dirt-cheap and flat-simple, like stacking old phone books under a desktop monitor or raising a line on cinderblocks. Other times, the answer involves months of work to introduce new tools, re-engineer workstations, and retrain the workers to use them properly. A textbook example of this second kind of successful project has been accomplished by toolmaker Honsa Ergonomic Technologies Inc. in the past year.

Honsa, based in Moline, Illinois, makes vibration-reducing, air-powered industrial tools such as chipping hammers, riveters, and grinding tools. The U.S. Navy has been using Honsa chipping guns for 10 years to dismantle nuclear submarines at a base in Bremerton, Washington, and through the Department of Defense identical tools have been sold to Russia for its nuclear submarine destruction program. Thomas W. Honsa, the company's president and CEO, said its products are in use in plants owned by Caterpillar, General Motors, Ford, DaimlerChrysler, John Deere, J.I. Case, Alcoa Inc., and Northrop Grumman, and in many smaller foundries. The project success discussed in this article is taking place at a car foundry owned by a company Honsa would not identify.

CTS, Tendinitis, HAVS

He said it began with Honsa's evaluation of the facility, which was experiencing a high volume of injuries, declining productivity, and an aging workforce. The workers were wielding air hammers on a long assembly line of about 120 workstations, running multiple shifts.

Workers were suffering from carpal tunnel syndrome and tendinitis. Some showed symptoms of hand-arm vibration syndrome, or HAVS, primarily experiencing the numbing and tingling at home when getting up in the morning, Honsa said.

The foundry said it had to have the same level of power in the new percussive tools--the same weight, and the same number of hits per minute--as in the old ones. The same chisels had to be used. But Honsa, which performed the ergonomic assessment of the assembly line in partnership with material handling manufacturer Knight Industries & Associates Inc. of Auburn Hills, Michigan, found a way to reduce the vibration by 40 percent by incorporating an isolation system in the tools' handles. Zero-gravity tool balancers were added, as well as lift tables and an overhead air supply system to take away the weight of the air hoses, Honsa said.

The balancers gave the operators a 180-degree range of chipping while dramatically reducing the weight they were lifting day in, day out. In the end, only about 20 percent of the tools on the line will change.

The Workers' Reaction

From beginning to end, the evaluation of the tools these workers were using lasted about nine months, said Honsa. The project had involved a pre-production run by Honsa of a prototype tool to make sure the foundry was satisfied. And it was, he said. "They're lining up at the door to get 'em. That's what I was told a week ago by our local rep."

Honsa conducted three seminars on site to explain the tool to the workers. "We had some women weeping," he said, "asking us, 'Where were you 10 years ago?' "

"It's been very successful," Honsa continued. "We expect a good year from that. And there are a significant amount of companies that are coming out of this" looking for help because they have similar problems to overcome.

Honsa, who is not an ergonomist, said he himself worked at age 17 behind a chipping hammer that had to have been hitting 110 decibels. Sound-damping products "are a little out of our tool realm," he said, but the small company's list of projects has included cutting the noise level of a Toyota brake manufacturer's 125-dB melt deck, a conveyor that was five feet wide and 144 feet long, with walls three and a half feet tall. Honsa lined it with damping material, bolted steel on the floor below and put a cover over the conveyor, dropping the noise level below 100 dB.

The company has been in business only since 1989 after Honsa came up with his vibration-damping design in 1987. Its first order came from a J.I. Case foundry in Racine, Wisconsin, which bought chipping hammers in 1989.

"We have a long laundry list of companies and people that use our product that have better lives because of it," said Honsa, who recently has fielded more phone calls than usual about his products and believes interest is growing because of OSHA's ergonomic rulemaking efforts.

"I think more and more people are going to take this proactive approach," he explained. "Let me put it this way: If you could drive a rivet with less vibration, why wouldn't you?"

Jerry Laws is the editor of Workplace Ergonomics.

Sept. 1998 - Modern Casting

New Installation

Vibration-Reduced Chipping Hammers Increase Worker Safety for Steel Caster

For Sivyer Steel Corp., a 300- employee steel caster in Bettendorf, Iowa, ergonomics issues have become an important concern. By producing castings from 5-20,000 lb., the foundry ahs learned to focus on safety measures in all its processes.In May, this steel caster made another investment in safety and health with the addition of three more vibration-reduced Chipping Hammers from Honsa Ergonomic Technologies, Inc., Rock Island Illinois. Since 1990, the foundry has purchased 22 hammers for use on its large agricultural steel castings in the finishing and refractory areas.We still have a few of the old type of hammers around, but the men always choose the Honsa hammers," said Curtis Lewis, general foreman at Sivyer Steel. Its definitely easier on the guys to work with every day.The chipping hammer's vibration reduced system is based on isolating the operating barrel or motor from the hands and arms of the operator. By installing a polyurethane vibration damping polymer between the tool and the operator, an isolation system is established top protect the user.According to the manufacturer, in a comparison performed by a workers compensation group, an old style-chipping hammer generated 100 m/secè of vibration, while the vibration reduced hammer produced 9.7 m/secè.Sivyer Steel's goal was to reduce the cases of carpal tunnel syndrome, vibration white finger and hand arm syndrome that are prevalent with vibration intensive, manual labor. But the foundry also didn't want to sacrifice quality. In a study by Midwest Univ.'s Dept. of Bioengineering, it was determined that the vibration-reduced chipping hammers efficiency was virtually double non-vibration damped tools.