Cam mechanism for a lens barrel

Cam mechanism for a lens barrel (10), comprising: a about an optical axis (O) rotatable first ring element (12), a second ring element (17) which is rotationally fixedly linearly along the optical axis (O) is conducted, and holds an optical element, a plurality of cam grooves (C17), which are formed on one of the two ring elements (12, 17) and have the same reference curve diagrams, and a plurality of cam followers (17c) which are formed on the other of the two annular elements (12, 17) and their associated cam grab in which the cam grooves and the cam followers comprise a single groove / engagement member set with a cam groove (C17S) and an associated cam follower (17s) and at least one groove / engagement member group having a front groove / engagement member set (C17f1, 17cf1), and a back groove / engagement member set (C17r1, 17cr1) which offset in the direction of the optical axis are arranged to each other are arranged with the single groove / engagement member set and the groove / engagement member group offset in the circumferential direction to each other, the cam groove of the single groove / engagement member-set the cam grooves of the groove / engagement member group ...