RIDE VIBRATIONS ON A 7.5 KW ROTARY POWER TILLER

The power tiller has become a versatile power source for small and med ium size farms in India owing to development of a variety of matching equipment. In order to overcome the problem of drudgery involved in it s operation, an operator's seat has been designed and developed. Power tiller ride vibration levels have been measured at man-seat interface along three mutually perpendicular axes viz; longitudinal, lateral an d vertical on four different terrains during the transport mode (with rotavator) and on three terrains during rotatilling. Measurements were taken at five throttle settings to obtain a range of engine speeds an d corresponding forward speeds. It was observed that equivalent accele ration levels increased as forward speed of travel increased under all operating conditions. Acceleration levels in the lateral axis were in significant. There was no conclusive difference between measured accel eration levels on untilled and tilled fields during transport and rota tilling. The measured ride vibration levels under different operating conditions were compared with the values specified under ISO 2631/1 (1 985) in relation to working efficiency and health and safety of the po wer tiller operator. On the basis of this study, it is concluded that exposure time for the power tiller operator should not exceed 2.5 h du ring rotatilling and 4.0 h during rotapuddling. Increasing exposure ti me may cause severe discomfort, pain and injury. (C) 1997 Silsoe Resea rch Institute.