Ride vibration on a 7.5 kW rotary power tiller

Abstract

The power tiller has become a versatile power source for small and medium size farms in India owing to development of a variety of matching equipment. In order to overcome the problem of drudgery involved in its 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 and vertical on four different terrains during the transport mode (with rotavator) and on three terrains during rotatilling operations. Measurements were taken at five throttle settings to obtain a range of engine speeds and corresponding forward speeds. It was observed that equivalent acceleration levels increased as forward speed of travel increased under most of the operating conditions. Acceleration levels in the lateral axis were insignificant. There was no conclusive difference in measured acceleration levels on untilled and tilled fields during transport and rotatilling operations. The measured ride vibration levels under different operating conditions were compared with the values specified under ISO 2631/1 (1985) in relation to working efficiency and health and safety of the power 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 during rotatilling and 4.0 h during rotapuddling operation. Increasing exposure time may cause severe discomfort,pain and injury.