TORSION 



117 



shaft is 5 in. Find the shear on each bolt when the maximum shearing stress in 

 the shaft is 9000 lb./in. 2 



213. A crank shaft revolves in bearings at A and B, as indicated in Fig. 91. 

 The cranks are in the same plane, and the crank-pin pressures P and Q are assumed 

 to act at right angles to the cranks. If P = 2500 lb., find Q and the reactions of 

 the bearings at A and B. Find also the maximum stress in the crank pin C and 

 draw the bending moment and shear diagrams. 



214. A crank shaft revolves in bearings at B and F (Fig. 92) and carries 

 two cranks C and E in the same plane. The shaft transmits a pure torque at 

 the left end, and the crank-pin pressures are assumed to act perpendicular to the 

 plane of the cranks. Find the stresses in the cranks C and E, and in the shaft at 

 B and D, and draw the bending moment and shear diagrams. 



215. A crank shaft revolves in bearings at B and D (Fig. 93), the planes of 

 the two cranks being 90 apart. Taking the dimensions given in the figure, 

 assume P = 3000 lb. and find Q, the reactions of the bearings, and the stress in the 

 crank pin C. 



