Reducing vibration in handheld power tools
30 March 2015
A new anti-vibration system almost entirely eliminates those uncomfortable sensations experienced when using handheld power tools.
The new Fein MultiMaster oscillator was developed by Fraunhofer researchers in collaboration with C. & E. Fein GmbH and it will be demonstrated at the forthcoming Hannover Messe (Hall 2, Booth C22) from April 13 to 17, 2015.
Researchers from the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt teamed up with their colleagues at C. & E. Fein GmbH to develop the technology for oscillating power tools – tools that do not have a rotating action, but rather one that moves back and forth - some as much as 19,500 times a minute. These and similar tools can do more than saw and sand; they are just as adept at rasping, polishing, shaving, cutting, severing, sharpening and filing.
“Elastomer elements are used to decouple the housing from the motor and act like a form of mechanical suspension and insulation,” says Heiko Atzrodt, group manager at Fraunhofer LBF. "Thus only a tiny portion of motor vibrations are transferred to the housing and so to the user."
However, too much isolation and the user would be unable to feel how hard they were working the tool, so the researchers had to strike a balance between reducing vibration and allowing users to retain a feel for what the toolwas doing.
This was achieved by adjusting the stiffness of the elastomer elements. First, the researchers used a simulation to determine the ideal stiffness range before integrating various suspension and insulation devices into a test system. This, in turn, allowed them to set the basic development parameters.
“By applying the anti-vibration system, Fein was able to reduce vibrations by up to 70 percent compared with previous models,” says Atzrodt. “For almost all applications, the oscillator now belongs squarely in the zero vibration class.” This means workers can use these tools for longer without having to take breaks. The tool is also easier on the ears: thanks to the new insulation, the acoustic output is reduced by 50 percent.
This low-vibration oscillator is now marketed under the name Fein MultiMaster FMM 350 Q. At Hannover Messe, the Fraunhofer LBF researchers will be offering visitors the chance to feel the difference for themselves by demonstrating the new oscillator next to its predecessor.