Comparing Simple Crank/Slider and Scotch Yoke Mechanisms

The simple crank/slider and the Scotch yoke (called the Donkey Crosshead in Great Britain) are two mechanisms for transforming between rotary and linear motion. This Demonstration compares the sliding joint kinematics—the displacements, velocities, and accelerations—produced by the two mechanisms as functions of the common input crank angle. The mechanism schematic shows the shared crank in black, the connecting rod of the simple crank mechanism in blue, and the Scotch yoke superposed in red. The kinematics for the sliding joint are plotted for a complete cycle in corresponding colors on the strip chart. To animate the Demonstration, click on the "+" to the right of the "crank angle" slider to open playback controls.