A machine vice has been designed as shown in the sketch below. The vice contains an ACME screw with an outer diameter of 12.6 mm and a root diameter of 11 mm. The collar diameter is 10 mm and the nut height/thickness is 16 mm. The coefficient of friction between the screw-nut is 0.15 (running) and the coefficient of friction between the screw and the collar is 0.15 (running).

1.Determine the torque applied to the screw if the operator can exert a maximum force of 168 N at the end of the handle.

2.What is the mean diameter of the screw?

3.What is the pitch of the screw?

4.Determine the clamping force developed by the vice while running.

5.Determine the efficiency of the vice while running.

6.Determine the shear stress on the threads for the given nut size

7.Determine the bearing stress on the screw threads.

8.What is the work done after 30 full rotations of the screw if the load remains constant.

 

12 100 16 Effective radius W 125 mm.