Subject:
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Re: Crane mathematics/netiquittte?
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 2 Aug 2005 21:17:30 GMT
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Viewed:
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3361 times
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In lugnet.technic, Ross Crawford wrote:
> In lugnet.technic, Nathan Bell wrote:
> > Does anyone who makes cranes have some easy math such as geometry for crane
> > design? The problem I see is that for a crane to be always balanced the weight
> > in the back needs to move according to the load weight.
>
> Hi Nathan, looking good! I wish I could be at Brickfest to see it.
>
> WRT balance, the answer is that cranes are very rarely in total balance. That is
> why they need such strong accurately machined turntables - the turntable is
> generally taking more weight on one side than the other. The trick is to work
> out the load charts so as to make sure the turntable is strong enough to take
> the maximum imbalance.
>
> Unfortunately in LEGO there is not much choice for turntables. The best for
> technic scale models is the technic turntable, which is quite good, but because
> it only clips together, there's a limit to the unbalance it can support. You can
> improve it by adding more rollers around it like Jen Clark did in her AC-50, or
> adding more support through the centre.
>
> Mobile and crawler cranes can be adjusted for different lifts by simply adding
> or removing ballast. But that is all worked out before the lift - the ballast
> never changes during a lift. Before the lift it will be very heavy in the rear,
> during the lift it will usually be heavy in the front.
>
> But many tower cranes have movable ballast, because it is difficult to add or
> remove ballast once it is erected. In fact some have ballast that is geared to
> the main boom, and is automatically moved backward as the boom is lowered.
>
> The other thing to consider is raising the boom - like on this CC2800
> http://www.brickshelf.com/cgi-bin/gallery.cgi?f=26905 the extra ballast at the
> rear was only required to raise the boom, and was disconnected during lifts.
>
> HTH
>
> ROSCO
Thanks Ross.
Hopefully the outriggers will not give way. I used the diagonal outriggers to
minimize the complexity of the crane mechanisms, but they may give way under the
wieght. I hope it is as good as your designs!
I just realized something- It is a general rule that posting a message on a forum to only one person is not good netiquitte. If I respond to your post then technically that is sending a post to one person. Every post is a search for feedback which generally comes from one or two people, and a response must be given to each one individually. Therefore, every post is, in a way, a post to one person. Where do we draw the line?
Nathan
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Message has 1 Reply:
 | | Re: netiquette?
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| (...) Its obviously OK to reply to an individual post. I think it's also OK to ask a question directed to an individual in a public reply (like "I like that MOC, how did you do such and such?"). But it's bad netiquette to start a thread with a (...) (19 years ago, 3-Aug-05, to lugnet.technic, lugnet.people)
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Message is in Reply To:
| | Re: Crane mathematics
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| (...) Hi Nathan, looking good! I wish I could be at Brickfest to see it. WRT balance, the answer is that cranes are very rarely in total balance. That is why they need such strong accurately machined turntables - the turntable is generally taking (...) (19 years ago, 2-Aug-05, to lugnet.technic)
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