Vibration Exposure in Forwarder Work: Effects of Work Element and Grapple Type

Abstract

Exposure to whole body vibration (WBV) is a major concern in mechanized forestry work because its adverse effects may become exacerbated by repetitive hand and arm movements, and nonneutral body postures. Moreover, shock-type vibrations have recently been suggested as a possible agent behind pains in the neck and shoulders of forest machine operators. Shocks have been identified in forwarders during loading, but the effects of crane work in forwarders have, to the best of our knowledge, not been studied. Thus, the aim of this study was to assess contributions of crane work elements, and potential effects of the use of three grapple and brake-link combinations, to vibration exposure levels in a small forwarder. Repeated measurements of cabin WBV were acquired, and work elements timed, as a single experienced operator forwarded wood piles on a standardized track in northern Sweden, using the same forwarder and work procedures with each grapple and brake-link combination. The studied crane equipment was found to have little or no effect on the daily WBV exposure. Furthermore, exposure to shock-type vibrations while loading appears to be due to driving rather than crane work. However, there were fewer collisions with remaining trees while using the tilt grapple with brake link, suggesting its use provides a more relaxed and comfortable work environment for forwarder operators and financial benefits for the forest owner by reducing damage in the remaining stand.