Question

Find the ratio of the time of cutting to the time of return stroke from the following information: A crank and slotted lever mechanism used in a shaper has a centre distance of 0.300 m between the centre of oscillation of the slotted lever and the centre of rotation of the crank. The radius of the crank is 0.120 m.

(a) 1.72

(b) 1.65

(c) 1.81

(d) 1.79

I have been asked this question during a job interview.

My question is from Single Slider Crank Chain and its Inversions in division Simple Mechanisms of Machine Kinematics

Answer 1

Correct choice is (a) 1.72

Explanation: We know that time of cutting stroke to the time of return stroke is given by

360-α/ α

Using trigonometric ratios we find that α =132.8°

therefore, Ratio = 1.72.