A single start square thread screw clamp is to be designed for a compressive load of 20 kN. The pad offers a friction torque of 30 Nm Calculate
(i) the pitch and diameter of the screw:
(ii) height of the nut and
(iii) dimensions of the tommy bar operating the screw Assume
Maximum force at the end of the tommy bar = 250 N
Safe compressive stress for the screw = 100 MPa
Safe bearing pressure for the screw and nut = 8 MPa
Safe bending stress in the handle = 95 MPa
Coefficient of screw thread friction= 0.15