Object is a pair of cam-operated switches. Each switch has a spring-loaded normally-open contact. A small roller on a swing-arm operates a push-rod to close the contact. When installed in a machine the arm bears on a cam on a shaft, and closes the contact for precise amounts of the rotation of the shaft. Switches of this kind are used in quantity in many IBM card-handling machines such as the 1401 and the 188 Collator in which these were found.
