Subject:
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Re: Drawbridge help needed!
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Newsgroups:
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lugnet.build, lugnet.trains
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Date:
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Thu, 28 Mar 2002 01:08:25 GMT
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Viewed:
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89 times
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In lugnet.build, Kim Toll writes:
> In lugnet.build, Pedro Silva writes:
> > I am currently building a small drawbridge for my train using Technic
> > elements, but I came across a difficulty which I was not expecting to be so
> > problematic: the need of a "counter-weight".
> > I did know I was *probably* gonna need one. And that there are ways to
> > calculate its weight and placement. Only I was expecting the gears would
> > hold... which they didn't.
> >
> > Has anyone made some bridges like this, that I can use as reference? Mainly
> > for the *shape* to use.
>
> Pedro,
>
> Here's my version of a draw bridge. Its the first listing under "Bridges"
> on my site.
>
> http://www.easystreet.com/~kjmrr/
>
> Its a Bascule bridge based on a real one I had a picture of in some train
> magazine.
>
> I got the counter balance to work fairly well. I could balance it such that
> it took very little force to lift the span. However, at this balance point
> the track wouldn't stay level - the end of the bridge would be a couple of
> inches up off the landing points. It would take some amount of force to
> hold the span DOWN in that situation. So I left it unbalanced enough that
> it held itself firmly in place as a train was crossing.
Your bridge has definately a very impressive mechanism. It does look a
little fragile, but I'm pretty sure it holds solid (it holds a train, right?
:-).
It is very complex, nonetheless. Isn't there any simpler (so to speak...)
solution? One less "sturdy"? You see, space is one of the issues I have to
deal with... :-/
In the meanwhile, I'll be testing your solution, possibly with modifications
to fit my bridge better.
> I was planning to motorize it, but never got around to it. My theory was
> that with a motor, I could balance it more closely and the tension provided
> by the gear train would hold the bridge in either the open position or the
> closed position, whichever way it was left. I never really tested that
> theory, but I still think it had a good chance of working.
The thinking seems correct to me. I believe the secret is the reduction
gear, it must be quite big to effectively slow down the bridge's axis (thus,
the bridge itself).
> Be sure to let us know how it goes.
> Kim
Will do!
Thank you for the tips, Kim. I'll try to adapt them this Easter, and then
I'll let you know what I found.
> P.S. I followed up to the trains group too, since this is a train bridge
> and it seemed appropriate.
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Message has 1 Reply:
 | | Re: Drawbridge help needed!
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| (...) Actually, its quite solid (or was - it is nolonger with us, may it rest in peace). Held two trains (its a double track bridge) quite easily, no problem. The counterbalance mechanism was quite study also. (...) Hmm... Well the space is mainly (...) (23 years ago, 28-Mar-02, to lugnet.build, lugnet.trains)
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Message is in Reply To:
| | Re: Drawbridge help needed!
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| (...) Pedro, Here's my version of a draw bridge. Its the first listing under "Bridges" on my site. (URL) a Bascule bridge based on a real one I had a picture of in some train magazine. I got the counter balance to work fairly well. I could balance (...) (23 years ago, 28-Mar-02, to lugnet.build, lugnet.trains)
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