The Impact Of Contact Force On The Accuracy Of Hand-Arm Vibration Measurement
Head of Marketing - Svantek Sp. z o.o.
Central Institute for Labour Protection – National Research Institute; Department of Vibroacustic Hazards, Warsaw, Poland
Measurement of hand-arm vibration with the use of a hand mounted sensor ensures achieving the most representative measurements, taken at the point of contact of hand with a vibrating tool. When measuring vibration on a hand, simultaneous measurement of contact force verifies whether the force magnitude is sufficiently rigid. The contact force also provides information on operator’s work schedule and may help to instruct operators if they are using excessive or too little force when working with hand-held tools. Additionally, by knowing both the coupling force value and the vibration acceleration, it is possible to calculate actual vibration energy dose that has been transferred to a hand.
The accuracy of vibration measurements using hand-arm adapters has been tested in 240 measurements in total, performed at the Polish National Research Institute at the Central Institute for Labour Protection. The impact of coupling force on vibration magnitudes has been assessed with Svantek’s SV106 human vibration meters and SV105AF hand-arm adapters (push force thresholds in tests were: 0 N, 20 N, 50 N, 100 N).
The results proved that measurements taken with hand-arm adapters provide correct vibration results regardless of contact force changes and type of vibration signal. The study has also indicated that it is necessary to define a minimum force threshold in order to mitigate the uncertainty related to the contact between hand and a vibrating tool.