Pivot Contact Behavior in Low-Inertia Snap-Action Rocker Switches

A study has been made of snap-action rocker switches to valuate some of the principal parameters contributing to the mechanics of operation. These are identified as the actuator and pivot radii and the distance of the actuator center of rotation above the rocking pivot. Equations are developed for the actuator/contact-blade angular velocity ratio as a function of blade angle. Graphs show that a knife edge pivot will produce a high velocity ratio for a low-mass blade. Further equations are resented showing the distribution of forces in the mechanism after the main contacts have met. The equations indicate that a make "up" configuration may have advantages in increasing pivot force and reducing pivot bounce in practical cases. This is borne out in tests on switches which show negligible bounce and reduced erosion for the make "up" arrange- ment.