WELL SWEEPS OF JAFFNA (துலா in Tamil language)
The guy walks back & forth on the Well sweep (Please note the fence in not shown in this picture)
The Jaffna is situated in Northern part of Sri-Lanka. It is famous for wells. Almost every house in Jaffna has at least one well. The wells are the main source of water in these areas.
In ancient times there were no motors to pump out waters so Well sweeps were used to get water from the wells.
Normally Palmyra tree or Coconut tree is used to make Well sweeps. A long iron rod is passed through the longitudinal middle of Well sweep. The Well sweep is based on two concrete walls via the iron rod. The Well sweep can swing up & down around the iron rod.
If you take a tree the upper side is thinner than the lower side. The upper side is faced towards the well. The bucket with rope is tied to the uppermost part of the Well sweep. In the lower part of the Well sweep heavy stones or heavy iron bars are hung to keep the Well sweep almost near to vertical position.
The rope should be in particular length that it must reach the well when the upper part of the Well sweep is pulled down & same time it must reach the upper level of the well when the Well sweep is in normal position.
The bucket is immersed whenever you pull the Well sweep down. Once you leave your hand without much effort the bucket filled with water comes out of the well.
If you are speaking scientifically it is the lever mechanism. A counter-weighted first-class lever used to easily raise buckets of water from a well.
In very olden days to water their field people used large bucket like structures made from Coconut or Palmyra leaves. Thus more energy is required to pull out these heavy structures a person used to walk back & forth on the Well sweep. In this case a special wooden fence is made around the Well sweep. Since you can hold this fence like structure you can avoid accidental slips.