Pencil sharpener is a kind of pencil sharpening tool. Pencil sharpener can be divided into ordinary pencil sharpener and electric pencil sharpener. Ordinary pencil sharpener is generally composed of three parts: blade, sheath and waste box, with low price. Electric pencil sharpener is more convenient to use, but the price is higher than ordinary pencil sharpener.

 

working principle

 

1. When turning the pen by hand, the friction force between the hand and the pen holder is used

 

2. There is friction when the pencil rotates on the inner wall of the rotary hole, because first of all, there is contact between them, strong interaction, and there is a certain rough surface - the friction coefficient is not zero, so we can effectively use the friction force

 

3. What really cuts off the wood on the pencil body is because of the powerful interaction between the pen and the blade. The blade is sharp and the pressure is high. The wood on the pencil body can be cut off because of the pressure, not the friction force.