Influence of Forward Speed and Terrain Condition on Hand Transmitted Vibration of Power Tiller

摘要

The operator of a power tiller must endure various environments and stress. Vibration significantly accelerates fatigue and affects sensitivity and reaction rates of the operator. The hand transmitted vibration (HTV) of walking type (7.46 kW) and riding type (8.95 kW) power tiller was measured and analyzed with respect to exposure time as per the guidelines of International standards ISO 5349 (1986). The operations included rototilling in unfilled and tilled field conditions at 1.5, 1.8, 2.1 and 2.4 km h~(-1) forward speeds and transporting at 3.5, 4.0, 4.5 and 5.0 km h~(-1) forward speeds on farm roads and bitumen roads. The HTV during rototilling with the 7.46 kW power tiller in an untilled field varied from 3.43 to 5.26 m s~(-2) restricting the exposure time from 1/2-1 h to < 1/2 h. In the tilled field, the values were 2.66 to 4.55 m s~(-2) and 1 to 2 h to < 1/2 h, respectively. The terrain condition of the untilled field resulted in 15.60 to 28.94 percent increased HTV. For the 8.95 kW power tiller, HTV varied from 3.31 to 5.09 m s~(-2) with an exposure time of 1 to 2 h to < 1/2 h. In the tilled field the values were 2.66 to 4.55 m s~(-2) and 1 to 2 h to < 1/2 h. The terrain condition of the untilled field was more pronounced with 16.47 to 30.31 percent increase in HTV. Among the power tillers, walking type power tiller registered 3.62 to 4.11 percent higher values of vibration. The HTV and exposure time during transport with the 7.46 kW power tiller on farm roads varied from 2.21 to 3.61 m s~(-2) and 2 to 4 h to 1/2 tol h. In the bitumen road the values were 1.67 to 2.77 m s2 and 2 to 4 h to 1 to 2 h. During transport with the 8.95 kW power tiller on farm roads the HTV and exposure time varied from 2.72 to 3.66 m s~(-2) and 1 to 2 h to 1/2 tol h with the increase in forward speed. In bitumen roads the values were 2.02 to 2.95 m s~(-2) and 2 to 4 h to 1 to 2 h. The terrain induced vibration of the 8.95 kW power tiller was 1.38 to 23.07 percent more on farm roads and 20.96 to 6.49 percent more on bitumen roads as compared to the 7.46 kW power tiller.