Machine Design I

A line shaft supporting two pulleys A and B is shown in Figure 1. Power is transmitted to the shaft by means of a vertical belt on the pulley A, which is then transmitted to the pulley B carrying a horizontal belt. The ratio of belt tension on tight and loose sides is 3:1. The limiting value of tension in the belts is 2.7 kN. The shaft is made of plain carbon steel 40C8 (\(S_{ut}=650\text{ N/mm}^2\) and \(S_{yt}=380\text{ N/mm}^2\)). The pulleys are keyed to the shaft. Determine the diameter of the shaft. Dimensions in the figure are in mm.