Chainsaws are widely used for timber harvesting operations. Vibration transmitted into the operator’s hand and arm system
by the chainsaw’s handle can cause vascular and neurological disorders. This article presents the results of operator
vibration exposure to three different chainsaws, equipped once with conventional and once with Kesper safety bar.
Measurements were done simultaneously on saws’ front and rear handle, both for sharpened and blunt chain, as well as for
three operational modes being cutting, limbing, and idling. Measurement and analysis of vibration were carried out
according to the guidelines of ISO 5349-1 and ISO 5349-2. The results show that root mean square (rms) vibration
acceleration was highest in the x-axis for front (in the vertical direction relative to the chainsaw up though the hand) and in
the z-axis for rear handle (perpendicular to the grip, up through the hand into the arm), respectively. For all measurements,
vibration at the rear handle exceeded that of the front handle. Differences in vibration between saws equipped either with
Kesper safety bar or with a conventional bar were not statistically significant. Frequency-weighted vibration (values for
sharpened chain) for cutting was between 4.39 and 4.96 m/s2. During delimbing values between 4.93 and 5.04 m/s2 were
recorded. Vibration for idling saw ranged from 5.87 to 6.15 m/s2