Thread: Never walk uinder a load

expensive...Like this one that happened in Qld

[ame=http://www.youtube.com/watch?v=KwDAXgmqBfc]YouTube - Crane Failure on dragline boon[/ame]

dad's mates at tafe send him that video and he showed me about a week ago. 28 seconds look for the peice of black material that shoots across the screen

Originally Posted by the fabricator

pretty self explainitory

Bit hard to read the name plate that is displayed towards the end, but it looks like that were over the safe workload by 15tonne so I'm not surprised that they had a failure if that is the case

imagine if they were planning to lift that housing with rotor out with the same crane

i feel sorry for the guy that scraped those bearing surfaces, must of taken ages

Back in the 70's I worked as a dogman for a month on a 24 story hotel building site. You learn pretty quickly to stand well out of the way of the rising load even if you put the chains and cables on the load yourself!

Originally Posted by the fabricator

imagine if they were planning to lift that housing with rotor out with the same crane

The bottom half of the turbine cylinder would only come out when the unit is being scrapped but they would have used that crane during construction. They could have even used 2 overhead cranes with a lifting beam between them. They would probably only use one to lift the top cover off. I've seen top covers lifted off and then turned over length wise without being put down using one crane with two hooks. A good rigger and a good crane driver are a pleasure to watch.

Originally Posted by the fabricator

i feel sorry for the guy that scraped those bearing surfaces, must of taken ages

Depends. If the bearings are new and have been machined properly there shouldn't need to be much scraped of the bottom half. The top half usually requires a bit to get the clearances right. It might surprise you how little they wear when in service if everything is working (and operated) as it should be. When in service there is no metal to metal contact (theoretically). the shaft rides on film of oil. There is a wedge shaped leadin on the leading edge of the white metal in the bottom half and the oil is pumped in under a bit of pressure, that and the rotating shaft causes an "oil wedge" which holds the shaft clear of the white metal.
In the bottom of all the bottom bearing halves there are also a couple of holes which are connected to another lube oil system called "jacking oil" This is used when first starting the unit. When the jacking oil is turned on the pressure is such that it "jacks" the entire rotor up off the bearing metal. Whilst doing maint work on the rotor, if the bearing caps are off and the jacking oil is turned on, if you look real close you can see the rotor come up. not much only a couple of thou. Once its up, 2 blokes can start turning the whole rotor (if its all coupled up) by pulling on the longest blades in the low press stage. Once its turning its quite easy for just one bloke to keep it moving slowly.

regards
bollie7

Yep know what its like 1st hand, I've been driving a crane and dropped the load much in the same manner of the video(machine malfunction).

DJ I seriously doubt that crane would be under rated for the job, its a gantry crane not a mobile crane. It would be designed to do the heaviest lift possible on the job.

Originally Posted by the fabricator

YouTube - Overhead Crane Failure - Drops 75 Tons!

pretty self explainitory

The gantry was not overloaded.I have seen this one and a follow up to it ,previously.
One of the sheaves collapsed under the load.The video version I saw was more detailed, showed the broken sheave and also mentioned the worker who was at the far end to guide the assembly as it was being seated in to position.

Fortunately he was following Safe Working Practice and did not allow himself to be caught in a pinch point under the load.

I too have dropped a heavy load.Four tons on heater head makes a very loud noise when it hits the concrete at 1.30AM .

In my case a chain snapped as I was turning the unit over.The chain was worn from continued dragging across the concrete.

To this day I am still wary of a suspended load and make it a point to check lifting hardware before use.

Grahame

I really hate using chains to lift any load, Even when new chain can break, Especially if it of imported asian stuff, Rated or not...
Just my opinion, No need to jump down my throat.
Matt

Matt,
In the late 70,s, chains or wire slings were the only options, the poly fibre slings we use in the present, did not come into general use until much later. There were flat fibre slings but the rating was low compared to what is available now.There was certainly nothing that could take 4 tons or more. The chains were the best HercAlloy grade available at the time.

An investigation into my accident found that the chains (worn from dragging them across the cement slab from the chain rack to the job) and the method of turning the units over needed improvement.We went from that to a wire sling and a fabricated fitting to a entry port.

This improved the control and no further incidents eventuated.

Grahame

HHhmmm, 75 tons seems to be a very overated/exagerarted weight for this particular turbine impeller.

Overhead gantry looks like it a bloody big one, spreader bar is rated for 60 metric tons and they use slings to lift it, so it will not get damaged.
The work enviroment looks like they WOULD NOT do anything illlegal or just plain stupid.

Now slings for a lift of 60 tons, will be a lot more substantial than two thin ones on each end, that is unless they have developed unbreakable slings made from kryponite.

Carted a few HEAVY loads around at different times and that turbine looks like it might only be about the 15 to 20 ton mark, could be wrong about this, possibly somebody else might know the true weight of the turbine impeller.

Moral stays the same though, dont walk under a heavy load.

mark

none of you guys should come and look in my work place unsafe is an understatement im very surprised an accident hasn't happened yet