A can opener is a kitchen utensil used to open canned goods. A manual can opener has four parts: the handles, the crank, the traction gear, and the cutting wheel. These parts are found only on a manual can opener. Handles
The body of a manual can opener consists of two handles connected with a single bolt, allowing them to be pulled apart and pushed together. Higher-quality can openers have rubber grips on the handles, making them easier and more comfortable to grip. Traction Gear
The traction gear is a small, round metal wheel with notches in it to increase its grip on the lip of the can. When it and the cutting wheel are pressed tightly against opposite sides of the lip of the can, the pressure against the surface of the traction gear causes it to grip the surface of the metal can when you turn the crank. Crank
A crank that can be turned by hand is attached to one of the handles. The axle of the crank goes through the handle and has the traction gear attached to the other side. When you use the can opener to open a can, you separate the handles of the opener, place the traction gear beneath the lip of the can and the cutting wheel above it, then bring the handles together, holding the lip of the can between the traction gear and the cutting wheel. Then you can turn the crank to turn the traction gear and propel the cutting wheel around the rim of the can. Cutting Wheel
The cutting wheel has a sharp edge around its edge. When you force the cutting wheel against the metal of the can by pushing the handles of the opener together, its sharp edge cuts through the metal. When you turn the traction gear by rotating the gear, the cutting wheel rotates as well, cutting through the metal as it moves around the lip of the can.