Design a bushed pin type flexible coupling for connecting a motor shaft to a pump shaft for the following service conditions. Power to be transmitted $=40$ kW$,$ speed of the motor shaft $=1000$ rpm$.$ The material properties are : i$)$ The allowable shear and crushing stress for shaft and key material is $40$ MPa and $80$ MPa respectively, ii$)$ allowable shear stress for cast iron is $15$ MPa, iii$)$ Allowable bearing pressure for rubber brush is $0\mathrm{.}8$ N$/$mm$2$ and iv$)$ the material of the pin is same as that of shaft and key. Draw neat sketch of the coupling