Question

The load cup of a screw jack is made separate from the head of the spindle to

(a) enhance the load carrying capacity of the jack

(b) reduce the effort needed for lifting the working load

(c) reduce the value of frictional torque required to be countered for lifting the load

(d) prevent the rotation of load being lifted

This question was posed to me in final exam.

My query is from Friction in Journal Bearing- Friction Circle topic in chapter Friction of Machine Kinematics

Answer 1

The correct choice is (d) prevent the rotation of load being lifted

To elaborate: In screw jack, the load to be raised or lowered, is placed on the head of the square threaded rod which is rotated by the application of an effort at the end of the lever for lifting or lowering the load.