Theory of Mechanism and Machine I

A cam, with a minimum radius of 25 mm, rotating clockwise at a uniform speed is to be designed to give a roller follower, at the end of a valve rod, motion described below: to raise the valve through 50 mm during 120° rotation of the cam; to keep the valve fully raised through next 30°; to lower the valve during next 60°; to keep the valve closed during rest of the revolution i.e. 150°. The diameter of the roller is 20 mm and the diameter of the cam shaft is 25 mm. Draw the profile of the cam when the line of the stroke is offset 15 mm from the axis of the camshaft. The displacement of the valve, while being raised and lowered, is to take place with simple harmonic motion. Determine the maximum acceleration of the valve rod when the camshaft rotates at 100 rpm.