الخلاصة

Abstract This research was conducted to evaluate WBV that harvester driver was exposed to it at different working conditions during paddy crop harvesting .the research involved three different investigation, the first to investigate the operations that the combine must do to achieve a paddy crop harvesting, while the second was to investigate the vibration emitted by different units of combine harvester and the third was the effect of threshing cylinder speed with three levels (800, 1000, 1200) rpm. The effect of the vibration at three orthogonal axes (X,Y,Z) and total equivalent vibration Av were tested . The vibration measured and defined according to the European Union guide (2002/44/EC Directive) as well as the organization of ISO ( ISO 2631-1-1997) . The RBCD with three replications was used .Each investigation considered as a single experiment and carried out individually. the results indicated that the vibration which the harvester driver exposed to it during paddy crop harvesting higher than the rest operations tested such as driving the harvester on the agricultural roads ,or on the rice field or when operated while the harvester at parking position . However, the value of that vibration exceeded the levels of ELV and EAV . Another wise that vibration value recorded 1.97 m/ s² Av which was considered very uncomfortable vibration level .The Y axis was the highest in vibration followed by the X axis , while the least value noted at the Z axis . Changing the number of harvester operating units led to clear changes in vibration generated in the three orthogonal axes , as well as Av value . However , this changes associated with the effect of road surface conditions . Increasing the threshing cylinder speed during paddy harvesting caused increasing vibration significantly at the X axis only while the Z and Y axes remained close to the safe levels of EAV and ELV respectively. The Av value was increased with increasing threshing cylinder speed.