Specification :

Typical cam-driven index drives have two basic elements: a cam attached to the input shaft (camshaft) and a follower wheel attached to the output shaft. As the cam rotates, followers on the follower wheel are guided through a path dictated by the shape of the cam.

During part of the input rotation, the cam confines the followers (and therefore, the output) to a rigid, stationary position called dwell. During the remainder of the camshaft rotation, the cam geometry caused the followers to move and the output to rotate. This movement is called an index. As the camshaft is rotated at a constant velocity, the output stops and starts (dwells and indexes) in a repeating pattern.