Machine Design

CHAPTER 16

Power Screws

Chapter Objectives

1. Determine the type of the thread and type of pitch series to be used in each application.

2. Calculate the amount of effort required to lift a load or to exert a thrust in each application.

3. Calculate amount of torque required to overcome friction in collar.

4. Calculate amount of torque required to overcome friction between screw and nut.

5. Calculate amount of total torque required to lift a load or to lower a load in each application.

6. Calculate the maximum principal stress and maximum shear stress developed in screw and nut due to applied load.

7. Determine the dimensions of screw and nut on the basis of allowable shear stress and allowable direct stress in screw and nut.

8. Determine the efficiency of each ...