Combining Simple Machines for Work and Fun

For hundreds of years, engineers and designers have been coming up with ways to convert rotary motion into useful work. A water wheel in a river can run a grain crusher, and the rotary motion from an electric motor can be used to drive the linear motion of a press. This happens through systems of cams and followers, cranks, and linkages. All complicated machines, mechanisms, and robots, are made up of a combination of simple machines. They help us convert rotary motion – the most common input motion – into linear, or up and down, output motion.

Automatons and mechanical toys have become favorite topics of many students in my class. Mechanical toys have been around for hundreds of years, and are some of the earliest examples of kinetic design. Often, a person would crank a handle, which wound a spring, then the stored energy would go about powering the toy. These toys were sometimes incredibly complex combinations of cams, linkages, springs, and components that often came in the form of dolls. These dolls could write poems or play the flute, based all on the interactions of mechanical parts with no electronics, sensors, or feedback at all. There are also some modern examples, from the work of Arthur Ganson to the toys made by Cabaret Mechanical Theatre and the paper machines from Flying Pig.

Project 8-1: Drawing Machine

Project 8-2: The Agreeable (Party) Sheep