The green and orange cams have different Archimedean profiles (pitches p1 and p2, p1 = p2/2). The green one is input.

Two cams rotate in the same direction with different speeds, like in a belt drive of two different pulleys.

Transmission ratio = 2.

Pitch of the Archimedean profile must be big enough to prevent possible jam.

A spiral spring can be used instead of the weight.