CAMS and FOLLOWERS

V. Ryan © 2002 - 2017

 PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET Have you ever looked closely at a simple mechanical toy ? If you have the opportunity to study one closely you will see that it is made up of mechanisms, usually including CAMS. Can you name any mechanical devices that use cams as part of its movement? A CAM changes the input motion, which is usually rotary motion (a rotating motion), to a reciprocating motion of the follower. They are found in many machines and toys A CAM has two parts, the FOLLOWER and the CAM PROFILE. Diagrams one to six show a rotating cam pushing a follower up and then allowing it to slowly fall back down. In diagram 1 the cam is in a vertical position and it slow rotates in an anticlockwise direction. As it rotates the follow drops down. In diagram 4 the follower is in its lowest position. The cam continues to rotate and the follower begins to rise in diagrams 5 and 6 until it returns to its original position. KEY PHRASES ONE CYCLE One rotation/revolution of the cam. DWELL When the cam rotates but the follower does not rise or fall. THE RISE That part of the cam that causes the follower to rise. What do you think is the 'FALL' ? TYPES OF FOLLOWER There are different types of follower but they all slide or roll on the edge of the cam. Various types are shown below. The cam seen below is a 'pear shaped cam'. As the handle is turned the cam profile rotates. The model moves forwards and backwards as a result. The movement is gentle although the faster the handle is turned the faster the movement of the model becomes. CLICK HERE FOR MECHANISMS INDEX PAGE

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