Brake drum 1 rotates about fixed axis A and has two wedge-shaped grooves a which are engaged by two wedged ridges b of lever 2. Lever 2 turns about fixed axis B and carries weight 3 which can be adjusted along guide d and clamped in the required position. Weight 3 presses ridges b of lever 2 into grooves a to brake drum 1.
$3390$SmF,Br$