Vibrations produced by electric shakers for olive harvesting

The paper reports the results of some experimental tests aimed at evaluating the effects of several manual electric shakers for olive harvesting on the vibrations transmitted to the hand-arm system. Three harvesting heads, different for number and arrangement of operating tools and oscillating system, each applied to three types of bars, different for material (carbon fibres and aluminium), diameter (35 and 40 mm) and length (2010 and 2210 mm), were considered. The vibrations were measured in two points, next to the hand positions on the bar in working conditions, at varying the bar inclinations (vertical, inclined at about 45 degrees, and horizontal). To smooth the influence of external factors, the machines were idle operated by the same person. The main results show that global accelerations are quite high (about 20 m/s2) and comparable with those measured when using mechanic or pneumatic machines, that the oscillating mechanism of the harvesting head affect the accelerations, that carbon fibre bar provide a significant reduction in accelerations with respect to the aluminium (16.3 vs. 21.2 m/s2), that the bar inclination does not affect the vibration level, and that the accelerations on the bar are greater than those on the handgrip (21 vs. 16 m/s2).