When pulley 1 turns clockwise, counterbalancing load 2 is lowered. This raises the right-hand end of lever 3 which turns about fixed axis A. The left-hand end with saw blade 4 is lowered to cut timber 5. Saw blade 4 is rotated about axis B through belt drive 6 which is powered by an electric motor mounted on the right-hand end of lever 3. When pulley 1 is turned counterclockwise, the saw blade is raised.
$2108$FL,FD$