Model: S17 Inversion of Hypocycloid Gear Train Ellipse and Straight-line Mechanism
This is an inversion of the hypocycloid mechanism of Model S-16. These two mechanisms are from a class of gear trains called 'planetary gear pairs' in which a usually smaller 'planet' gear rotates around a larger 'sun' gear. (See models in Series G.) In both models however the planet gear rotates on the inside surface of a ring gear. In Model S-16 however, the ring gear is fixed. In Model S-17 the smaller planet gear rotates with a crank and the ring gear moves up and down in the vertical direction producing an exact straight-line motion. The term 'hypocycloid' refers to the curves that are generated by points on the perimeter of the planet gear when it rotates on the inside of a ring gear.
Francis Moon 2003-07-01