Drawing board 1 slides along fixed guides a-a. Two identical pulleys 7 and 8 rotate about fixed axes B and A, and two identical pulleys 9 and 10 rotate about fixed axes D and C. Flexible link (cable) 4, attached to drawing board 1 at point F, runs over pulleys 8 and 7, and its other end M is attached to counter-balancing weight 3. Flexible link (cable) 2, attached to board 1 at point K, runs over pulleys 10 and 9, and its other end N is attached to counterbalancing weight 11. Flexible links (cables) 5 and 6, attached to board 1 at points E and L, run over pulleys 9 and 7, and their other ends, at points N and M, are attached to weights 11 and 3. Thus two flexible links 4 and 6 run over pulley 7, and two, 2 and 5, run over pulley 9. Weights 3 and 11 are selected so that drawing board 1 is in equilibrium in any position with respect to the base.
$3533$CFL,ML$