The influence of the exploitation time on chain saws vibration level

The paper presents the results of research of the vibration levels changes on the motor chain saw handles during exploitation. The examination sample comprised randomly selected chain saw from 12 forestry offices of the State Enterprise Croatian Forests. Three types of motor chain saws were tested in two different working conditions: at idling and at full load. The vibration levels were measured in all three axes simultaneously. The WAS-values (weighted acceleration sum) were calculated for the front and rear handles. The aim of the measurements was to establish certain ergonomic characteristics of motor chain saws depending on the time of use. For 276 chain saws a detailed analysis of the dependence between the time of their use and vibration levels on their handles was conducted. The examination results showed that the vibration level did not depend on the working time, either on the front or on the rear handles.