Roller 8 rotates about an axis rigidly attached to link 2 and rolls and slides along the groove of cylinder cam 1. The square shank of cam 1 slides in a guide of base 5 so that cam 1 can only reciprocate without rotation. Driven link 4 can rotate with respect to cam 1. When driving worm 3 rotates, link 2 also rotates, since its worm gear meshes with worm 3, and cam 1 and link 4 reciprocate along axis A-A. When supplementary drive 7 is switched on, its pinion, meshing with the internal gear of link 4, transmits rotation as well to this link. Screw 6 serves to adjust the position of roller 8 and cam 1 with respect to link 2.
$3312$GrC,ML$