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Subject: 
Re: Liebherr LR-1750 Completion Photos
Newsgroups: 
lugnet.technic
Date: 
Thu, 10 Nov 2005 15:10:49 GMT
Viewed: 
5064 times
  

30 lbs!  I did not realize it took that much weight to balance the boom, but I
guess that makes sense.  40 hrs is not much time at all for a design that big.
Is it possible to build a crane that tall without grounded support in the rear?
I mean is it possible to build one like that that is free-standing?  That is not
a critisism but just a question to increase personal learning.

As far as the "grounded support" that you are referring to, on the real crane it
is called the "suspended ballast" On the real LR-1750, the guys for it are
attached to hydraulic cylinders which can raise and lower the ballast.
Therefore it can be raised off of the ground when the crane rotates.  I tried
doing this with pnumatic cylinders, but obviously they were not strong enough to
lift that kind of load.  Instead, when I need to raise the ballast to slew the
crane, I can spool out line on the A-frame, which in turn raises the superlift,
lifting the suspended ballast off of the ground.  This technique works pretty
well.  I can also detach the suspended ballast once the crane has been raised to
above 45 degrees, and it will not turn over as long as I dont put too much of a
load onto it.  All in all, this design worked out pretty well.

It must be strong to withstand a 15 mph wind! I think you have set records with
your cranes that may never been broken.  How much can it lift?  Would adding a
load make it withstand even greater wind resistance?  It sure dwarfs my crane!

So far, with that much boom installed, it can only lift a weight of 10 lbs to a
height of about 11 feet or so. If I remove the jib, I have taken 20 lbs to a
height of 8 feet.  I was messing around in the garage the other day, and I was
almost able to lift a half-full keg off of the ground using the LR-1750 along
with the LR-11200.  I just need to make some more counterweights, and a stronger
spreader bar, and I think that I will be able to make the lift.  Stay tuned for
picture of that.

Keep up the good work!

Thanks for the compliments

-Alvin.



Message is in Reply To:
  Re: Liebherr LR-1750 Completion Photos
 
(...) 30 lbs! I did not realize it took that much weight to balance the boom, but I guess that makes sense. 40 hrs is not much time at all for a design that big. Is it possible to build a crane that tall without grounded support in the rear? I mean (...) (19 years ago, 1-Nov-05, to lugnet.technic)

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