The purpose of master thesis was to investigate the impact of characteristics of skid trails on exposure of a skidder driver by whole-body vibration. Measurements of the intensity of whole-body vibration were carried out on and under the seat of an Ecotrac 120V skidder on 50-meter sections of a forest road and a skid trail at rest and during the movement of the skidder. In case of driving empty, the measurements were performed at 1000, 1500 and 2000 rpm of the skidder motor and, in case of driving full, at 1500 rpm. Roughness index (HRI) was obtained by means of terrestrial laser scanning of both routes. We established that the exposure of whole-body vibration increases with increasing roughness of the basis. We measured the highest exposure to vibration (up to 1.6 m/s2) in axial direction. In general, it is evident that the intensity of vibration increases in all directions (X, Y, Z) and their vector magnitude (RMS VTV). Measurements showed that according to the RMS VTV indicator the vibration intensity when driving empty is 7.4 to 28.1 times higher than at rest. We also found out that the intensity of whole-body vibration when driving empty on a skid trail is 1.5 to 2.4 times higher than when driving empty on road, according to the RMS VTV indicator. Seat reduces the exposure at standstill, at higher skidder speeds when driving empty and mostly when driving full on a skid trail and increases them when driving on a road or a basis with low roughness and when driving empty at low speeds. Assuming that the intensities of vibration add up by individual factors, we evaluated the contribution of each factor to the final intensity of vibration. Thus, we can conclude that speed is the most important factor which affects the intensity of whole-body vibration, followed by the roughness of the basis. Measures for reducing the exposure to vibration are: adjustment of the driving speed to the roughness of the basis, operation of a forestry machine with tire pressure as low as conditions for safe work allow, maintenance of the skid trail foundation, selecting a properly cushioned and fixed seat and organizational measures that reduce the exposure time of a worker to the exposure to vibration.
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