1. A C-clamp uses a TR203 trapezoidal thread screw. At the end of the screw there is a 24 mm diameter collar, rigidly attached to the screw. The friction coefficient between the collar and part is 0.2 while that in the screw-nut is 0.15. What force has to be applied at the end of the handle to generate a 300 N clamping force? What is the maximum direct stress in section A-A of the clamp? What is the maximum shear stress at a point in that section? Dimensions in mm. 140 A 12 0 A 3 150 Hints: a) use the relationship between torque and axial force in a motion screw. Make sure that you include the friction in the collar. b) Section A-A of the clamp is subjected to tension by the clamping force (W) and by bending because this force is applied eccentric (bending moment M=Wx0.14). The direct stress due to tension has the same direction as the bending stress. On one side of the axis of symmetry they add and on the other they subtract. The direct stress is just force divided by area and the bending stress is given by bending formula. c) the maximum direct stress calculated at the previous point is the maximum principal stress. The other principal stress (horizontal direction is zero); it follows that the maximum shears tress is half the maximum direct stress calculated previously.