From 1790 to 1880, the U.S. patent application process required the submission of a working patent model to demonstrate the device being patented. These miniature machines, which could be no larger than a 12-inch cube, were working show pieces created by skilled craftsmen.
Patent models offer insight into the intense technological advancement of the Industrial Revolution. Thousands of these fascinating models have been collected by Alan Rothschild, proprietor of the Rothschild Petersen Patent Model Museum, and many were exhibited for the first time at the Smithsonian American Art Museum in 2011–2013. President Obama displays several patent models from the Smithsonian collection in the Oval Office.
I first encountered Rothschild and his patent models at the 2013 World Maker Faire in New York City. We were thrilled to accept a challenge from Maker Media’s Brian Jepson to create a 3D-printed working replica of one of the coolest models in the Rothschild collection. The Electro-Magnetic Engine, U.S. patent #122944, was patented in 1872 by Charles Gaume of Williamsburg, New York. The model uses a complex system of rotating brass wheels to pulse electromagnet coils and rotate an armature of iron bars, converting electrical energy into mechanical energy. The sequencing system rapidly turns the magnets on and off to keep the wheel spinning. Today, this ingenious mechanism is duplicated electronically in the brushless motors used in everything from PC fans to quadrotor drones.