In both these models, a rotary motion is transmitted into a rectilinear motion. In the upper model, the two studs on the rotating disk strike the elbow shaped arm or bell crank (See No. 10) in rotation and it in turn works between the two studs on the horizontal bar, pushing it back and forth across a field. The rectilinear motion of the lower model is caused by the three projections revolving inside of the horizontal shaft. The motion in both also alternates back and forth.
[Virginia Downward & William M. Clark, 1930]

[Editor’s Note: These two models are examples of intermittent motion or dwell mechanisms. The lower mechanism is contained in the three-tooth clock escapement in the Cornell Kinematic Reuleaux Model Collection, Model X03. FCM]

Francis Moon 2005-00-00