Monday, July 10, 2006
Tower cranes
Good morning,
Is the tower crane the national bird of Singapore ?
It has been said that the national bird of Singapore is the tower crane. This crane is all over Singapore. So, is the statement apt ?
Well, if it is, then this crane also belongs to other developing countries, ha ha ha !
Anyway, the tower crane is not a real bird. It is a large machinery use in moving heavy things at construction sites, upwards and in any other direction.
We all see them, yet has any body ever wonder how these cranes grow taller. They sit on a tower and lift things; so, do they lift themselves ? If they do, how ? If not what lifts them ? Otherwise, what ... ?
The tower crane arrives at the construction site on tractor-trailer rigs. The crew uses a mobile crane to assemble the jib, the horizontal arm, and the slewing unit, the machinery section, and places these members on a mast (may be 6 metres sections). The mast is a large, triangulated lattice structure (may be 3.2 meters square). The triangulated structure gives the mast the strength to remain upright. The mobile crane then adds the counterweights, and the crane is ready for operation.
To rise to a new height, the crane grows itself one mast section at a time! The crew uses a top climber or climbing frame that fits outside the mast, and that climbs up to the top of the mast and to the slewing unit .
Then the following process takes place:
1. The crew first hang a weight on the jib to balance the counterweight.
2. Then they fasten the climber to the slewing unit and detach that from the mast.
3. Then they use large hydraulic rams in the top climber to raise the jib and the slewing unit up a section height (6 metres).
4. The crane operator then uses the crane to lift another mast section (6 metres) into the gap opened by the climbing frame.
5. After that they bolt everything back in place.
And with that the crane is (6 metres) taller ! How clever !
Once the building is finished and it is time for the crane to come down, the process is reversed. The crane disassembles its own mast, section by section, and then smaller cranes disassemble the rest.
Any doubt why man is the king of creation.
Have a nice day
Ronald
Is the tower crane the national bird of Singapore ?
It has been said that the national bird of Singapore is the tower crane. This crane is all over Singapore. So, is the statement apt ?
Well, if it is, then this crane also belongs to other developing countries, ha ha ha !
Anyway, the tower crane is not a real bird. It is a large machinery use in moving heavy things at construction sites, upwards and in any other direction.
We all see them, yet has any body ever wonder how these cranes grow taller. They sit on a tower and lift things; so, do they lift themselves ? If they do, how ? If not what lifts them ? Otherwise, what ... ?
The tower crane arrives at the construction site on tractor-trailer rigs. The crew uses a mobile crane to assemble the jib, the horizontal arm, and the slewing unit, the machinery section, and places these members on a mast (may be 6 metres sections). The mast is a large, triangulated lattice structure (may be 3.2 meters square). The triangulated structure gives the mast the strength to remain upright. The mobile crane then adds the counterweights, and the crane is ready for operation.
To rise to a new height, the crane grows itself one mast section at a time! The crew uses a top climber or climbing frame that fits outside the mast, and that climbs up to the top of the mast and to the slewing unit .
Then the following process takes place:
1. The crew first hang a weight on the jib to balance the counterweight.
2. Then they fasten the climber to the slewing unit and detach that from the mast.
3. Then they use large hydraulic rams in the top climber to raise the jib and the slewing unit up a section height (6 metres).
4. The crane operator then uses the crane to lift another mast section (6 metres) into the gap opened by the climbing frame.
5. After that they bolt everything back in place.
And with that the crane is (6 metres) taller ! How clever !
Once the building is finished and it is time for the crane to come down, the process is reversed. The crane disassembles its own mast, section by section, and then smaller cranes disassemble the rest.
Any doubt why man is the king of creation.
Have a nice day
Ronald
# posted by chunmu @ 8:06 PM 
