Cast aluminum and wood (painted) on a vertical panel.
For educational use only. All rights reserved by the contributor(s) and publisher(s).
pulley, belt drive
Step type. The top pulley is the driver. The rate of speed depends upon the diameter of the pulleys. The lower shaft revolves the slower because the belt is on the small pulley of driver and large pulley of the lower or driven shaft; The speed [ratio] is reversed when belt is on large pulley at top and small pulley below.
Variable speed type. The upper cone pulley is the driver and has a constant speed. The position of the belt regulates the speed of the lower cone, making it variable. When the belt is on the left, the [lower shaft] speed is minimum and, as it travels along the cone to the right, it increases proportionally as the diameter of the lower cone.
[Virginia Downward & William M. Clark, 1930]
[Editorís Note: The relative speed of the two shafts is inversely proportional to the ratio of diameters of the driven and driving pulley wheels. Reuleaux called these mechanisms, 'tension organs' since the connecting belts have to be in tension in order to create the friction between the belt and the cylinder. Several Reuleaux-Voigt models illustrate similar transformations of motion using belt mechanisms in the 'V' series; the step pulley drive is model V-12. Continuous speed ratio mechanisms have been used in some automotive applications. FCM]