Characteristics of hand-transmitted vibration of a hand tractor used in three operational modes

Hand tractor is extensively used as a mechanical source of farm power for small and medium size farm. Vibration transmitted from the handles of the hand tractor to the operator causes discomfort, pain and early fatigue. This paper presents the results of hand-transmitted vibration in actual field conditions during transportation on tarmacadam road, rota-tilling in untilled field and rota-puddling in submerged field. Ten representative hand tractor operators were selected for the study. Hand-transmitted vibration was measured and analyzed as per the guidelines of ISO 5349-2 [2001. Mechanical Vibration – Guidelines for the Measurement and Assessment of Human Exposure to Hand-transmitted Vibration. Part – 2: Practical Guidance for Measurement at the Workplace. International Standard Organization, Geneva]. Data were collected at three levels of forward speed, i.e. 1.11, 1.71 and 2.31 m/s during transportation and 0.30, 0.45 and 0.63 m/s during rota-tilling and rota-puddling. The results indicate that root mean square (rms) vibration acceleration was highest in the Xh-axis followed by the Zh- and Yh-axes. The peak vibration acceleration was 5.52, 8.07 and 5.27 m/s2 at the frequency of 31.5 Hz during transportation, rota-tilling and rota-puddling, respectively. Vibration total values (ahv) were highest during transportation followed by rota-tilling and rota-puddling operations. Analysis of variance (ANOVA) indicated significant effect (p < 0.01) of forward speed of the hand tractor on hand-transmitted vibration during all the three modes of operation.Relevance to industryThis study emphasizes the need to provide intervention to reduce hand-transmitted vibration of the hand tractor for increasing comfort and safety of the operators and to reduce early fatigue, which may ultimately increase the adoption of hand tractor by more farmers.