Question

What is the purpose of double hooke’s joint?

(a) Have constant linear velocity ratio of driver and driven shafts

(b) Have constant acceleration ratio of driver and driven shafts

(c) Have constant angular velocity ratio of driver and driven shafts

(d) Have constant angular acceleration ratio of driver and driven shafts

I have been asked this question in exam.

The question is from Double Hooke’s Joint topic in section Friction of Machine Kinematics

Answer 1

The correct option is (c) Have constant angular velocity ratio of driver and driven shafts

To elaborate: The velocity of the driven shaft is not constant, but varies from maximum to minimum values. In order to have a constant velocity ratio of the driving and driven shafts, an intermediate shaft with a Hooke’s joint at each end is used.