Linkages Reverse Motion Linkages Bell Crank Parallel Motion Linkages Push Pull LinkagesPulleys and Gears Pulleys Gears Idler Gears Changing Direction of Motion Bevel Gears Worm Gears Rack and Pinion Gear Ratio Velocity Ratio Worked Example of Velocity Ratio Worked Example of Output SpeedLevers Class 1 Levers Class 2 Levers Class 3 Levers Mechanical Advantage Velocity Ratio EfficiencyCams Cranks and Followers Follower Pear Shaped Cam Heart Shaped Cam Eccentric Cam Rotary Motion Reciprocating Motion Examples of Everyday Cranks