analysis of daily exposure of operator to vibrations of a power tiller

vibration from the operation of industrial implements can be harmful to the human body. these implements, such as the power tiller or hand tractor often used to till rice in northern iran, can vibrate the entire body or one part, particularly the hands. in this research, the transmissibility and effects of vibration from a mitsubishi power tiller of 7.7 hp and 2400 rpm on the operator’s health was evaluated. the experiments were conducted in two positions (moving by hand and tilling), five speeds (1600, 1800, 2000, 2200, 2400 rpm), at three points (power tiller grip, operator’s arm, operator’s chest), and three modes (vertical, lateral, longitudinal). it was observed that with an increase in engine speed at the three points, the total acceleration value, ahv, increases. it was also observed that the dominant frequency of vibration at all points and modes corresponds to the piston strokes or revolutions per second of the motor. it was observed that the value of exposure to vibrations in an eight-hour work day, a(8), was 19.14 m/s2, which is more than the standard value of 2 m/s2 that is known to cause health disorders in the operator. it is predicted that use at this exposure will cause blanching of the fingers and vascular disorders of the hands for 10% of the machine operators within two years.