WHOLE-BODY VIBRATION OF TRACTOR DRIVERS DURING HARROWING

The seat vibration of nine tractors was investigated while drivers har rowed fields in eastern Finland. The vibration acceleration of the tra ctor driver's seat was measured simultaneously along three mutually pe rpendicular axes. The triaxial seat-accelerometer was used for the mea surements. The vibration signals were amplified with charge amplifiers and recorded with an FM tape recorder. The samples were analyzed with a real-time analyzer. In all cases, the average vibration of the seat exceeded the 8-hour ''fatigue-decreased proficiency boundary'' specif ied in the international standard ISO 2631/1. The instantaneous accele rations of the most harmful one-third octave band of vibration were so metimes two- to threefold compared with the average.