Answer to Question #336068 in Mechanical Engineering for veer

Question

A screw jack is to lift a load of 80 kN through a height of 400 mm. The elastic strength of screw material in tension and compression is 200 MPa and in shear 120 MPa. The material for nut is phosphor-bronze for which the elastic limit may be taken as 100 MPa in tension, 90 MPa in compression and 80 MPa in shear. The bearing pressure between the nut and the screw is not to exceed 18 N/mm2 . Consider factor of safety equal to 2 and coefficient of friction between screw and nut (µ)= 0.14. Design the screw and nut only. Refer the table shown as below for standard dimensions of screw.