pulley

A pulley is a wheel with a rope, wire, or chain around it which is used for changing the direction of force.


Pulley
Source
Pulley
http://etc.usf.edu/clipart/25700/25757/fixed_pulley_25757_md.gif

Simple Machine

A simple machine is a simple device for altering the size or direction of a force.


Simple Machines
Source
Simple Machines
https://mmelundy.files.wordpress.com/2014/04/six-simple-machines-graphic-english.jpg