The green and orange cams of Archimedean profile are identical. The green one is input.
Two cams rotate in the same direction with the same speed, like in a belt drive of two equal pulleys.
If the cams have different pitches of Archimedean profile (p1 and p2) then transmission ratio = p1/p2.
Pitch of the Archimedean profile must be big enough to prevent possible jam.
A spiral spring can be used instead of the weight.