I have had problems in the past finding royalty free clip art that clearly depicted the different types of simple machines I teach in my 6th grade science class. So instead of searching, I created my own to use in SMARTboard activities, handouts, and PowerPoint presentations.
The 58 pieces of clip art included in this compressed folder include 15 different examples of simple machines, both labeled and unlabeled. An example of each of the three classes of levers is included, along with 3 different pulley systems and inclined planes. A screw and a wedge are also depicted. All of the images are presented on a white background in a .png file format for easy inclusion into documents and activities. Each has a black and white version, as well as the color version.