A double dwell cam mechanism has a motion function which follows a rise-dwell-fall-dwell motion function sequence that repeats.

Unlike the single dwell, the rise function position ends with the follower’s acceleration becoming zero, as it is stationary in the first dwell. Only after the first dwell does the acceleration become non-zero again during the fall function, returning the follower back to its original position and staying stationary again during the second dwell.