Without my wife's asking me to watch how a crane grows taller, I would never have experienced it in my life.The construction of the extension block of the Prince of Wales Hospital has been in full swing over the past year and throughout this year. There are three tower cranes of different heights located at different corners of the building site.
Yesterday and today I witnessed how these self-assembling tower cranes, called “Kangaroo cranes”, could grow themselves. Let us first see how the farthest and the tallest crane grew.
(1) A “jack” (積) (the red coloured ones in all the photos but the yellow one in the second last photo) first crawled up the tower on rails powered by a motor on a platform to reach the turn-table from where the white cabin (inside which the crane operator was sitting) was hanging.
(2) Then the jack shouldered the whole crane at the turn-table and the top of the tower is detached from the turn-table.
(3) The jack went on moving up so that it left an empty room for a new section of the tower to be inserted.
(4) Meanwhile, another new section from the ground was lifted.
(5) Two brave men climbed onto the overhanging section and hooked this section onto a horizontal bar as a temporary support. Then they released the wire that was tied to the section and let go the “Hook” of the crane.
(6) Altogether four men pulled the section into the hole and fixed them in place by hammering in the necessary screws and fastened them with nuts.(7) The process was repeated until three such sections had been fixed to the tower.
It is interesting indeed to see such a “growing” technique and I have learned a lesson on mechanical engineering.
Do you know why these cranes are called "Kangaroo" cranes? Think!
1 comment:
They are called "Kangaroo cranes" because as the buildings keep going up, the cranes are able to "jump" upward to always remain above the top level.
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