Link 3 rotates together with disk 7 about fixed axis A. Link 2 is connected by turning pairs B and C to links 3 and 1. Link 1 has cam a of oval shape at its other end. When link 3 is turned counterclockwise with respect to disk 7, shoes 4 and 5 are spread by cam a in the slot between disks 7 and 6, thereby engaging the clutch so that disk 6 begins to rotate. When link 3 is turned in the opposite direction with respect to disk 7, the clutch is disengaged and disk 6 stops rotating. The mechanism is held in the disengaged position when pivot C bears against a pin which is not shown.
$1700$LC,C$