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Subject: 
Re: Drawbridge help needed!
Newsgroups: 
lugnet.build, lugnet.trains
Date: 
Thu, 28 Mar 2002 02:11:53 GMT
Viewed: 
106 times
  
In lugnet.build, Pedro Silva writes:
In lugnet.build, Kim Toll writes:
Here's my version of a draw bridge.  Its the first listing under "Bridges"
on my site.

http://www.easystreet.com/~kjmrr/

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?
:-).

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.

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... :-/

Hmm... Well the space is mainly vertical.  Is that a limitation for you?  Or
do you mean the space it takes behind the bridge? (before the start of the
bridge?  I'm not quite sure how to express that thought...)

I'd guess that this is a pretty economical solution for this problem.  I
don't necessairly mean my personal implementation, but the counterbalance
design in general.  Thes bascule bridges have been used many times in the
real world, and I'm sure they've done enough work to be sure that they are
mechanically viable.

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).

Yes, I agree completely.
Kim



Message has 1 Reply:
  Re: Drawbridge help needed!
 
(...) The latter. I'm not sure if I can fit such a big structure behind the bridge, since it is possible that other structures may interfere with that placement of the counterbalance mechanism (namely, a possible crossing viaduct). I dunno, I must (...) (23 years ago, 28-Mar-02, to lugnet.build, lugnet.trains)

Message is in Reply To:
  Re: Drawbridge help needed!
 
(...) 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 (...) (23 years ago, 28-Mar-02, to lugnet.build, lugnet.trains)

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