Rigidly attached lobe members 1 and 2 rotate about fixed axis A. Working surfaces a-a and b-b of members 2 and 1 are profiled a long the same curve. Follower 3 oscillates about fixed axis B and carries roller 4 which rolls a long the working surface of the lobe members. By angularly displacing members 1 and 2 with respect to each other and clamping them rigidly together again in the required position, the total working surface of the cam can be varied, thereby varying the phases of motion of follower 3.
$3143$SmC,LL$