A screw jack mechanism is required to raise or lower 500 lbf (see Figure). A single square thread…

Need your ASSIGNMENT done? Use our paper writing service to score better and meet your deadline.


Order a Similar Paper Order a Different Paper

A screw jack mechanism is required to raise or lower 500 lbf (see Figure). A single square thread nut having 5 teeth per inch and a nominal diameter of 0.8 – inch isused and the nut rotates at 300 rpm. The coefficient of the running friction at the screw is 0.12 whereas the collar is designed to maintain zero friction.Determine:
(a)- the pitch:
(b)- the lead:
(c)- the lifting speed of the jack (inch/min.):
(d)- Complete the Table below:

Case Torque Required Power to Efficiency
Drive the Screw
Staring to Raise :
Running to Raise :

Starting to Lower :
Running to Lower :