This linkage system can be used to slowly pull back on a cable connected to a spring or other elastic device and then suddenly release tension on the cable. As the wheel rotates, the pin is able to capture the first linkage bar (green). Notice that the second linkage bar (red) is raised above the first linkage bar and will never be captured by the pin. Slowly drag the slider to the end and watch the quick release.
Contributed by: John Albers (Department of Mathematical Sciences, Ball State University)