Cam 1 rotates about fixed axis A and has three profiled lobes a composed of tangent circular arcs. Follower 2 reciprocates in fixed guides B-B and carries two rollers 3 which contact lobes a of the cam. Positive motion is achieved because all diameters of the pitch, or theoretical, curve of the cam, passing through centre A, are equal to distance C͞D between the centres of rollers 3. In one cycle, follower 2 has three rises and three returns.
$2983$SmC,3L$