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Subject: 
Re: The Big Crane At Brickfest
Newsgroups: 
lugnet.technic, lugnet.modelteam
Date: 
Mon, 29 Jul 2002 22:04:20 GMT
Viewed: 
33 times
  
Gordon,

When you wan't to lift such a heavy load the technic axles are too weak. So
you have to use other materials than LEGO. I've made a 4.2 metres high
Liebherr LG1550 and know how far you can go with it. A hundred kg's seems
impressive, but is impossible. I know a guy who build a crane with a very
strong beam. The maximum he could lift was about 15 kg's I think. I studied
the boom: it really is strong. LEGO is plastic and plastic is not the
strongest material in the world. When it was, most crane where made of
plastic ....

Dennis

In lugnet.technic, Gordon Bentley writes:
In lugnet.technic, Dennis Bosman writes:
9.5 pounds = ... kgs??? Sounds heavy, so the crane has a great lifting
capacity. Is the boom strongs enough??? You have to take care of sufficient

Dennis,

Booms made of Technic beams like this are remarkably strong. I am working on
a crane as well (who isn't!) and have tested the boom to 100Kg direct load
and it doesn't even look like moving. I was pretty amazed about this result
myself.

So far I've finished the rotating frame, boom, A-Frame and winches,
turntable and cross-frame. Testing with this on a flat base, I find the main
limitation is the load that the winches will take without the gearbox
pulling apart. I have succssfully lifted 12 Kg with a 4:1 block. At 16 Kg,
the winch broke, but the rest of the structure is fine. These are controlled
lifts where the weight is picked, either luffed, or rotated and put down
again. Note I am working at Technic Figure scale of around 20:1. My ultimate
goal is to lift 40-50 Kg.

Now I've just got to keep buying sets to get enough parts to complete the
crawlers. And some pulleys for a bigger set of blocks.

Regards
Gordon



Message has 1 Reply:
  Re: The Big Crane At Brickfest
 
Thanks for the reply Dennis. So far, I haven't hit problems with the axles. I am making sure every load bearing axle has at least two shear planes for this reason. Also doubling up on gears (tandem) and making sure all axles are supported everywhere (...) (22 years ago, 30-Jul-02, to lugnet.technic, lugnet.modelteam)

Message is in Reply To:
  Re: The Big Crane At Brickfest
 
(...) Dennis, Booms made of Technic beams like this are remarkably strong. I am working on a crane as well (who isn't!) and have tested the boom to 100Kg direct load and it doesn't even look like moving. I was pretty amazed about this result myself. (...) (22 years ago, 26-Jul-02, to lugnet.technic, lugnet.modelteam)

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