Researchers Develop System to Assess Vibration Exposure during Power Tool Use
A research team from IRSST, a nonprofit scientific research organization in Quebec, Canada, has developed an inexpensive system intended to help assess the risk of injury associated with the use of various types of power tools. The “hand-handle coupling-force measurement system” uses thin, flexible, resistive sensors to measure the forces exerted between a user’s hand and the handle of a vibrating portable power tool. 
According to the research report, the assessment of hand-transmitted vibration exposure and of potential injuries to workers’ hands and arms from the use of hand-held power tools is currently based on guidelines in ISO 5349-1, Mechanical vibration — Measurement and evaluation of human exposure to hand-transmitted vibration. However, those guidelines do not account for the effects of the coupling forces exerted at the hand-handle interface, which is “partly attributed to the lack of practical methods for measuring hand-tool interface forces in field applications and in part to the lack of sufficient data relating injury risks to the applied forces,” the report reads.
Researchers found that the sensors can measure the forces exerted by workers’ palms and fingers as long as each one is calibrated to the subject before measurements are taken.
“Regardless of the size of the hand and the handle, [these] sensors have shown good linearity with push and grip forces and provide reproducible results on both flat and curved surfaces,” said Subhash Rakheja, coauthor and professor at Concordia University in Montreal.
The report is available on IRSST’s website.