تأثیر جرم راننده بر سلامتی و آسایش او و مدت زمان مجاز رانندگی در سه نوع تراکتور متداول در ایران

Occupational safety and health of agricultural workers have not yet received their due attention in developing countries. This is particularly true in the case of tractor drivers who operate tractors in unfavorable conditions and in a high level of seat and tractor vibrations. Therefore, an investigation of vibration sources and finding the methods for decreasing them are of considerable importance. In this research, vibrations that the tractor operators of different weights are exposed to while operating any of the three commonly used tractors in Iran during plowing with moldboard plows, disk harrows or routine road travel at two forward speeds were examined. Acceleration data of tractor body and its driver, while riding the tractor, were measured and recorded. Later, Fast Fourier Analysis, and root mean square of weighted accelerations for the cases of driver health and comfort were analyzed and evaluated. Results revealed that the level of forward speed did not have any significant effect on vibrations introduced to drivers body, however, the average of acceleration vectors on different tractors and their drivers’ bodies revealed a significant influence (P<0.01). Moreover, with increasing a driver’s mass, the average of acceleration vectors on his body decreased. For example, a driver of 55 kg mass, bore a maximum acceleration vector of 9.8 m/sec2, while a driver with 100 kg mass, had a minimum acceleration vector of 3.3 m/sec2. In a comparison of permissible riding hours/day, JD3140 and U651 tractors recorded maximum and minimum, respectively. Also acceleration vectors for different tractor operators compared with international standards showed that the comfort level for these tractors was extremely low.