A Pulley

A pulley is like an iron pipe. Pulleys are put on each end of the bed. The pulleys are as wide as the "bed". Each pulley has a steel shaft through it.
The shaft turns on a bearing . . . and the pulley turns with the shaft.

What is a bearing?

When two pieces of steel touch each other; they cannot turn easily without bearings. Bearings use little steel balls to keep the pulley shaft and the conveyor bed from rubbing together. Now the shaft can turn easily.

Pulley "A" is the drive pulley. Pulley "B" is the tail pulley. The drive pulley is usually larger because it does the work.

How the drive pulley does the work

The drive pulley is turned (driven) by a motor. A sprocket is put on the drive pulley shaft.

A sprocket is put on the motor.

What is a Sprocket?

A sprocket is a metal "wheel" with "teeth" on the outside.