To be of practical use, the safety sleeve described in the preceding problem must be free...

To be of practical use, the safety sleeve described in the preceding problem must be free to slide along the rail when pulled upward. Determine the largest allowable value of the coefficient of static friction between the flange of the rail and the pins at A and B if the sleeve is to be free to slide when pulled as shown in the figure, assuming la (a) θ= 60°, (b) θ = 50°, (c) θ= 40°.