Question

When the elements of the pair are kept in contact by the action of external forces, the pair is said to be a

(a) lower pair

(b) higher pair

(c) self closed pair

(d) force closed pair

This question was addressed to me by my school teacher while I was bunking the class.

Question is taken from Simple Mechanisms in section Simple Mechanisms of Machine Kinematics

Answer 1

The correct choice is (d) force closed pair

The explanation: When the two elements of a pair are not connected mechanically but are kept in contact by the action of external forces, the pair is said to be a force-closed pair. The cam and follower is an example of force closed pair, as it is kept in contact by the forces exerted by spring and gravity.