Safer Saws Help Save Fingers

23 Jul, 2007 By: Michelle Nicolson

An Oregon company invents a table saw that can tell the difference between wood and human hands.

It's an occupational hazard in the woodworking profession: saws that cut wood with ease can also slice though human flesh in a fraction of a second. The U.S. Consumer Product Safety Commission estimates that table saws are involved in more than 60,000 accidents every year -- averaging one accident every nine minutes. Those accidents result in nearly $2 billion of injury-related costs annually. Often these injuries result in serious injuries as well as amputations, mostly to fingers.

But a small Oregon company is working to make the industry's workers safer with its table saw that cuts only wood -- not fingers. Recognizing the need for a safer saw, lifelong woodworker Steve Gass applied his doctorate in physics to design a saw that runs with a small electrical current applied to the blade. To develop and market his idea, Gass formed SawStop . The company's goal is to see its safety technology incorporated into every type of woodworking equipment sold so that the number of debilitating injuries to woodworkers can be dramatically reduced. After all, as the company says, it's a question of when, not if, these injuries happen when you work with wood.

Stopped in the Nick of Time
When the SawStop blade touches a finger (or something else that conducts electrical current), the current drops and engages a brake. As the blade's teeth sink into the brake, the rotation of the blade stops in about three milliseconds, then the blade drops below the table in about 15-20 milliseconds (assuming the blade was running at the maximum height). The process is so quick that it is visually undetectable -- the blade simply disappears. In a woodworking shop, that safety mechanism makes the difference between a small nick treatable with a band-aid or an injury that costs an average of $45,608 in medical treatment, as estimated by OSHA.

"I think of it as a seat belt or air bag for table saws," Gass said.

The SawStop table saw in action.

Developing the technology was one hurdle, but finding the right CAD program was another challenge for the SawStop engineers. After a false start with another CAD program, the company settled on SolidWorks and implemented it in August 2003. They chose the program for compatibility because their manufacturer in Taiwan also used the software. The company worked with Shounco Design Studios , a SolidWorks reseller, to help train their employees to use the program.

"We're all inventors or engineers, but none of us really had any CAD experience," said Dave Fulmer, SawStop vice-president of engineering. "In just a couple of weeks learning SolidWorks, we were able to design complex components such as the brake mechanism, including the spring that sets the brake into the blade to stop the saw."

A profile of the SawStop table saw blade and brake mechanism in SolidWorks.

Once installed and trained though, SawStop engineers could see immediate improvements in their workflow. "We estimate that we have seen a 20% reduction in design time since converting to SolidWorks. The reduction is due to increased compatibility, increased stability, and increased features," Fulmer said.

Additionally, Fulmer and his team of engineers also used COSMOSXpress and COSMOSWorks Designer analysis software to ensure the table saws performed as expected and could stand up to constant use. The company credits SolidWorks' integration with these products as one factor that allowed SawStop to minimize prototyping costs and time and eliminate added manufacturing costs from overbuilding.

So far, the SawStop table saw has already prevented nearly 150 serious injuries, and the company knows that number will increase as sales continue to grow. Harder to calculate is the savings in workmen's compensation insurance to those employers, not to mention the physical and mental well-being of the employees and their coworkers who have SawStop to thank.

To see the SawStop table saw in action, download the video available on the company's Web site .

About the Author: Michelle Nicolson

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