Cam 1 rotates about fixed axis A and has groove c profiled along an Archimedian spiral. Follower 2 turns about fixed axis B and carries roller b which slides and rolls along groove c. The polar equation of the theoretical, or pitch, curve of the spiral groove is ρ=aφ where a is a small value. Consequently, the groove has about ten turns, and a cycle of rise and return of follower 2 corresponds to about twenty revolutions of cam 1, ten in each direction.
$3013$SmC,3L$