Identical pulleys 4 and 5 rotate about axes E and F of platform 3 which is to be raised and lowered. Identical pulleys 8 and 9 rotate about fixed axes D and A. Rigidly attached pulleys 10 and 11, and 12 and 13 rotate about fixed axes C and H. Identical pulleys 6 and 7 rotate about axes K and B of counterbalancing weights 1 and 2. Endless flexible link 14 runs over all the pulleys in the following sequence: 5, 12, 7, 13, 8, 4, 10, 6, 11 and 9. Platform 3 is raised or lowered with translational motion along axis y-y by rotating pulley 10 or 12 about axis C or H.
$3561$CFL,MH$