Cam 1 rotates about fixed axis A and has profile a-a along a logarithmic spiral. Follower 2 reciprocates in fixed guide b and has flat surface f which is tangent to profile a-a of cam 1. Pressure angle α, between normal n-n to the cam surface and axis Ay of follower motion, is constant for the given profile. When cam 1 rotates continuously counterclockwise, follower 2 has a period of free fall in each revolution. The mechanism is stopped when cam 1 begins to rotate clockwise and face c of the cam runs up against follower 2.
$2989$SmC,3L$