7.1.1 : What is a lever

• A lever is a board or bar that rests on a turning point. It has three components 

• Fulcrum - the turning point of the lever

• Load - the object moved by the lever (or the force applied by the lever)

• Effort - the person pushing the lever (or the force applied by the lever)

First class lever

Second class lever

Third class lever

7.1.6 : What is a reverse-motion linkage

• A reverse-motion linkage is a linkage that reverses the direction of motion. When the top bar is pushed to the left , the bottom bar moves to the right. The bars move in opposite directions , with the fixed pivot point as the centre of rotation.

7.1.7 : What is a parallel-motion linkage 

• A parallel-motion linkage is a linkage that creates identical parallel motion.

7.1.8 : What is a crank?

• A crank is a mechanism that converts rotary motion into either reciprocating or oscillating motion using linkages , and vice versa.

7.1.9 : What is a quick-return crank?

• A quick-return crank is a mechanism that also converts rotary motion into reciprocating motion. When the drive wheel rotates , the arm moves forward and backward. However, the forward and return strokes have different speeds.

7.1.10 : What is a bell crank?

• A bell crank is a linkage that converts horizontal movement into vertical movement , and vice versa.

7.1.11 : What is a crank-and-slider linkage?

• A crank-and-slider linkage is a mechanism that converts rotary motion into linear motion, and vice versa. 

7.1.12 : What is a cam ?

• A cam is a mechanism that converts rotary motion into reciprocating motion. It is made up of two parts : the cam and the cam follower.

Pear cam

Circle cam

Heart cam

Snail cam