Vibration Transmission to the Hand-Arm System by Means of Portable Olive Beater: the Effect of Body Mass

Abstract

Olive is one of the oldest cultivated fruit in Mediterranean basin countries. Currently, full mechanic harvesting is getting more and more spread in super high density orchards for oil production, nevertheless in small sized farms (as well as in those producing table olives) hand harvesting by means of olive beaters is still the most used method. When operating hand held olive harvesters, workers undergo high levels of hand-arm vibrations (HAV). The prolonged exposure to these types of stresses could cause the so called hand-arm vibration syndrome (HAVS).
To determine which factors significantly affect operators’ exposure, five operators having different body mass indexes were monitored. They were requested to operate a battery powered olive beater both in idling and simulated working conditions and the vibrations transmitted to their hand-arm system were acquired by means of daily calibrated ICP triaxial accelerometers. Rough data were processed in compliance with the UNI EN ISO 5349-1:2004 and 5349-2:2015 standards to calculate the vibration total value (a_v) the hand-arm system as the square root of the sum of the squares of the frequency-weighted accelerations along the axes (a_wx, a_wy and a_wz). Further processing foresaw statistical comparison tests and multivariate processing by means of Principal Components Analysis (PCA).
According to results, a_v values at the rear handle resulted lower than those at the front one in all the conditions and for all the operators. Multivariate analysis pointed out that, besides the axis of the vibration, operators’ bodies can influence the recorded acceleration values.