Question

A cup is provided in screw jack

(a) to reduce the friction

(b) to prevent rotation of load

(c) to increase load capacity

(d) to increase efficiency

This question was addressed to me during an interview for a job.

This interesting question is from Friction of a V-thread topic in chapter Friction of Machine Kinematics

Answer 1

Right answer is (b) to prevent rotation of load

For explanation: For the prevention of the rotation of load being lift, the load cup of a screw jack is made separate from the head of the spindle.