Portable equipment for field measurement of the hand's absorption of vibration energy

Abstract

Risk assessments for hand-transmitted vibration, according to international Standard ISO 5349, are based solely on the acceleration level measured directly on the vibrating surface. An alternative method could be to measure the quantity of vibration transmitted to and absorbed by the operator. These types of measurements have until now only been possible to conduct in laboratory environments using specially-designed handles. The aim of the present project has therefore been to develop portable equipment for field measurements of the hand's absorption of vibration energy. The developed equipment consists of a hand-held adapter placed in the contact area between the hand and the vibrating surface. The adapter is equipped with transducers for measurement of vibration and dynamic forces. For the force measurements, four different technical solutions were tested. An adapter, equipped with a triaxial piezo-electric force transducer as well as piezo-electric accelerometers, was found to be the most suitable solution for field measurements. The adapter is small, has a low weight and can be used for measurement on tools with different handle designs. The adapter has been tested by laboratory measurements and reliable and accurate measurement results were obtained within the frequency range of 3 to 1900 Hz, for all the three orthogonal directions in accordance with ISO 5349.