Question

In a four bar linkage, s denotes the shortest link length, L is the longest link length, P and Q are the lengths of other two links. At least one of the three moving links will rotate by 360° if

(a) S + L < P + Q

(b) S + L > P + Q

(c) S + P < L + Q

(d) S + P > L + Q

This question was addressed to me during an interview.

This interesting question is from Inversion of Mechanism topic in portion Simple Mechanisms of Machine Kinematics

Answer 1

Correct choice is (a) S + L < P + Q

Explanation: According to Grashof’s law for four bar mechanism, the sum of shortest and longest link lengths should not be greater than the sum of remaining two link length.

i.e.  S + L < P + Q.