I have changed the design slightly. There is no pulleys or cross beam. You didn't raise any question on the wooden stage. So, i assume it is correct.
Will it work out if we use two parallel PI shaped iron pillars and steal cylinders instead of pulleys as shown in the picture periya_koil_saaram_3rd_try.gif? Please see the top view given in the left bottom corner of the picture for more details.
It is neither rope nor chain but a kind of MURUKKU KAMBI.