This model illustrates a method for reducing speed and obtaining an out of line or off center drive. The shaft carrying the three red arms revolves twice for one revolution of the green slotted disk.
[Virginia Downward & William M. Clark, 1930]

[Editor’s Note: This model was originally numbered #48 in the Newark Museum installation but is now numbered #111 at the Museum of Science in Boston. The title 'multiple gear' seems to be a misnomer. This mechanism is closer to a radial arm slider-crank in which the crank is grounded and the connecting link (one of the three rotating arms) is rotating. Clark designed this model after Figure 27 in the 1868 catalog of Henry T. Brown on mechanical movements. This model is similar to the Cornell Reuleaux Models Q-7, Q-8. In the Clark models each of the three arms engages the slot with a circular pin. In the Reuleaux models the engaging elements have specially shaped teeth called cycloids. FCM]

Francis Moon 2005-00-00