Cam 1 rotates about fixed axis A. Follower 2 reciprocates in fixed guides B-B and carries knife-edge a which slides along contour b of cam 1. Rigidly attached to follower 2 is pointer 4 whose tip coincides with point A when follower 2 is in its extreme right-hand position. The contour (working surface) of cam 1 is designed so that the tip of pointer 4 describes a three- leafed rose when cam 1 rotates. Knife-edge a is held in contact with cam 1 by spring 3.
$3115$SmC,Ge$