Friction wheel mechanisms transmit motion from one wheel to another through rolling. In order to transmit a tangential force or torque across the wheels, a normal or radial force is usually required. In this model the normal force is created by a weight acting through a lever. The two iron surfaces produce a small contact area due to elastic deformation called "Hertz contact" named after the mathematical engineer who studied the stresses between solids in contact. Reuleaux called these "force closed" mechanisms.

In W-1, a small force on the crank or small wheel axel can lift a larger weight on the larger wheel axel. This model was designed to be used with a pedestal and weights (Model W-7: missing in the Collection) with which one can measure the maximum load that the friction wheel can carry without slipping.

Francis Moon 2003-07-01