Model: Y10 Variable Speed Friction Wheel Transmission of Sellers
The transmission of rotary motion between one axel and another can be made through toothed wheels, belt and pulley systems or by the use of friction wheels as shown in Model Y-10. The basic principle of the friction wheel is contact of one wheel with another, thereby constraining the two surfaces to have the same velocity. This requires contact pressure between the surfaces in order to generate friction forces between the two wheels. The continuous contact and smooth motion has advantages over toothed or geared wheels in that there is no engaging and disengaging of gear teeth, hence less noise and wear. The friction wheel has the disadvantage of limited torque to avoid slipping between the wheels. Reuleaux designed a half dozen models with friction wheels [See the W model series.] In model (Y-10), the friction wheels are part of a variable speed drive attributed to Sellers.

Francis Moon 2002-00-00