Amacam, Ada Berani...??

Tower Cranes Climbing...

How Much Weight Can They Lift?

by Marshall Brain

A typical tower crane has the following specifications:

• Maximum unsupported height - 265 feet (80 meters)
  The crane can have a total height much greater than 265 feet if it is tied into the building as the building rises around the crane.

• Maximum reach - 230 feet (70 meters)
• Maximum lifting power - 19.8 tons (18 metric tons), 300 tonne-meters (metric ton = tonne)
• Counterweights - 20 tons (16.3 metric tons)

The maximum load that the crane can lift is 18 metric tons (39,690 pounds), but the crane cannot lift that much weight if the load is positioned at the end of the jib. The closer the load is positioned to the mast, the more weight the crane can lift safely. The 300 tonne-meter rating tells you the relationship. For example, if the operator positions the load 30 meters (100 feet) from the mast, the crane can lift a maximum of 10.1 tonnes.

The crane uses two limit switches to make sure that the operator does not overload the crane:

• The maximum load switch monitors the pull on the cable and makes sure that the load does not exceed 18 tonnes.
• The load moment switch makes sure that the operator does not exceed the tonne-meter rating of the crane as the load moves out on the jib. A cat head assembly in the slewing unit can measure the amount of collapse in the jib and sense when an overload condition occurs.

Now, it would be a pretty big problem if one of these things fell over on a job site. Let's find out what keeps these massive structures standing upright.

How Tower Cranes Work...?

Parts of a Tower Crane

by : Marshall Brain

All tower cranes consist of the same basic parts:

• The base is bolted to a large concrete pad that supports the crane.
• The base connects to the mast (or tower), which gives the tower crane its height.
• Attached to the top of the mast is the slewing unit -- the gear and motor -- that allows the crane to rotate:

On top of the slewing unit are three parts:

• The long horizontal jib (or working arm), which is the portion of the crane that carries the load. A trolley runs along the jib to move the load in and out from the crane's center:

• The shorter horizontal machinery arm, which contains the crane's motors and electronics as well as the large concrete counter weights:

• The operator's cab:

The machinery arm contains the motor that lifts the load, along with the control electronics that drive it and the cable drum, as shown here:
The motors that drive the slewing unit are located above the unit's large gear:
Now let's find out how much weight this equipment can handle.

Imbasan Berita : 'Nyawa Orang Dulu Baru Nyawa Sendiri...'

Feb 24, 2008
NUS crane tragedy: One worker died a hero
Crane operator's actions moments before machine toppled may have saved lives of many workers, students
By Nur Dianah Suhaimi CRANE operator Mohamad Homsen Kassan died a hero last Friday. Seconds before his 72-tonne crane toppled, he shouted a warning to fellow workers at the worksite below his perch. It bought them precious moments to run helter-skelter for safety at the worksite in the National University of Singapore (NUS) campus. Then, even as the 60m-high tower crane tipped over, Mr Homsen, 46, swung the boom away from the nearest building, the NUS Business School. EYE-WITNESSES SAY crane operator Mohamad Homsen Kassan swung the boom away from a building as it toppled. The crane plunged to the ground. Trapped in his cabin, he died from multiple injuries to his body. His younger brother Rafie Kassan, 37, sketched Mr Homsen's final heroic moments to The Sunday Times yesterday, based on accounts given by eye-witnesses. 'If not for him, many other workers and students could have died,' he said. Witnesses said that as the crane fell, it hit a tree and very narrowly missed the bus stop near the NUS Business School. The crane toppled at about 2.15pm and the victims were pronounced dead by paramedics. Rescuers used power tools and airbags to extricate the bodies of Mr Homsen and Mr Thinatharan. The Chinese national was found lying on the ground beside the crane. Two other workers from China were also hurt. All five workers were employed by sub-contractors on the site. The firms were redeveloping the area around the three-storey NUS Society Kent Ridge Guild House. More than 50 family members, friends and colleagues turned up at the Choa Chu Kang Muslim Cemetery yesterday afternoon for Mr Homsen's burial. Many wondered how such an accident could have happened despite stringent safety rules at construction sites. Said Mr Zulgaffar Mohamad Yusuf, 41, a crane instructor and Mr Homsen's friend: 'I've been operating cranes for almost 20 years but never heard of a 60m tower crane collapsing. These things are usually very stable.' Mr Rafie, a taxi driver, said: 'There are so many tower cranes. This site has only one and it turned out faulty.' Separately, Mr V. Ravindran, 43, the elder brother of Mr Thinatharan, also voiced his disquiet. 'What if the crane had fallen onto the university bus stop?' he said. Another crane operator with more than 10 years' experience but who declined to be named, said: 'The boom is attached to the crane by pins and screws. If the pins or screws crack, the boom can get detached.' Industry insiders said that it is standard practice for all cranes to be checked first thing in the day. It is not known whether the crane belongs to the site's main contractor Kimly Construction or was leased from another firm. The company could not be reached for comment. Mr Homsen began operating cranes 16 years ago. His supervisor, Mr Abdul Rahim Rahmat, said: 'Homsen was very experienced and skilled at his job.' He was a divorcee and had no children. He leaves an 84-year- old father and 10 siblings. p/s : Al-Fatihah untuk arwah...amin.

The First Tower Cranes Blog in Malaysia...?

Alkisah seperti diriwayatkan berikut merupakan reaksi pertama salah seorang daripada sahabat karib ayahteh apabila dimaklumkan tentang kewujudan laman blog towercrane.com...in Malaysia ini, katanya spontan...

"...aku rasa ko jadi blogger pertama di Malaysia yang buat blog kren macam ni..."

Mmm...mungkin kot. Tapi apa la yang ada pada perkataan 'pertama' tu? Belum tentu orang ambik port benda-benda macam tu...! Tak heran punn...

Personally bagi ayahteh blog ini tidaklah seberapa, cuma berbentuk informasi semata-mata berkenaan kerjaya Operator Kren Menara ni, itu saja.

Zaman sekarang zaman teknologi maklumat, jadi mahu tak mahu kenalah kita mengikut peredaran semasa tu agar sentiasa dapat bersaing dengan bangsa-bangsa lain...tidaklah kita terus dikata ketinggalan zaman.

Hari ini internet digunakan sebagai medium utama untuk mendapatkan pelbagai maklumat dan panduan...pendek kata, di Internet ni macam-macam ada & tiada sempadan!

Jadi tidaklah menjadi satu kejanggalan rasanya jika towercrane.com...in Malaysia ini diwujudkan bagi memacamkan lagi keadaan yang dah sedia macam-macam tu...hehe.

Jika zaman ayahteh dulu, untuk mendapatkan maklumat lanjut berkenaan sesuatu kerjaya itu memang bukan main seksa lagi...terpaksa 'mengemis' buat muka tempe ke hulu ke hilir untuk mendapatkan kerja...

Nak cari kerja kena guna modal juga, dalam pada masa yang sama juga nak cari modal pun kena ada kerja dulu...! Jadi pening gitu je...huhu.
Last-last mak bapak juga jadi mangsa!

Bagi ayahteh, kita perlu mengetahui sedikit sebanyak berkenaan sesuatu kerjaya itu untuk mempersiapkan diri sebelum membuat sebarang keputusan. Apabila kita dah yakin baru kita boleh bertindak untuk 'terjun' ke dalamnya...takdelah kita jadi 'bidan terjun' pulak.






p/s : Terima kasih kepada sahabat-sahabat yang banyak membantu dari segi teknikal & idea sehingga wujudnya laman blog towercrane.com...in Malaysia ini.
To blogger afeazd...thanx a lots bro!

All Nice Picture Collection...!