Has anyone built a powered Liftup Bridge?

ByngGiraud

ByngGiraud

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Has anyone powered a lift up bridge?
I have a 1 meter access I wish to bridge.
I will try a roll up shutter motor & control, but here in Germany it would be 220 volts.
A counter balance may be necessary. If this works, I will try a 2 part bridge powered from either side of the access.
 
I am sure 'someone' will have done this..

I think I would look to lower voltage motors?
I have seen car window lift-mechanisms, used for point-motion, on 7 1/4 inch track. - Perhaps these could be adapted?
Lower (safer) voltage, and vehicle dismantles, may be less costly?

Good luck, and keep us informed of your progress.

PhilP
 
ByngGiraud said:
Has anyone powered a lift up bridge?
I have a 1 meter access I wish to bridge.
I will try a roll up shutter motor & control, but here in Germany it would be 220 volts.
A counter balance may be necessary. If this works, I will try a 2 part bridge powered from either side of the access.
Click to expand...
A most inventive chap called David Stuart made a very impressive pair of lifting bridges, using what looks like the sort of powered pistons you find on a motorised car tailgate although they might have been 12V linear actuators from an adjustable bed - if you are on Facebook, there is some info on the group gscale.net.
 
Here is a useful 1:1 concept.

You are not actually lifting anything - the counterbalance weights do most of the work. I believe there is one somewhere which relies on a cog and rack arrangement to roll the bridge back and thus raise the arms.

Pardon our interruption...

www.ebay.co.uk

EDIT - and the famous Pegasus Bridge

Pegasus Rolling Lift Bascule Bridge — South East London Meccano Club

A club for Meccano enthusiasts in London, holding four meetings each year and a public Meccano Show in Falconwood.
selmec.org.uk selmec.org.uk
 
Playmobil produced a level crossing with their original track-powered trains where the barriers were raised by a cog mechanism operated by turning a handle. A suitably modified version of this idea might work.

Alternatively, why not have a counterweight do the lifting work with cables from the bridge base being wound down to lower the bridge.
 
I came across this one on t'internet
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I like the way the counterweights block off the tracks when the bridge is raised

Rik
 
An electrical car window opener works just fine. No, if it would just quite raining , Iwould like to install it in place.
The test mode' is a 6 inch board for the span. Now to build a bridge.
 
I missed the start of this discussion due to life getting in the way and disrupting railway affairs, so it may be too late to be helpful. However, I built a number of rather smaller trunnion-type bascule bridges with a simplified drive system using a dc gearmotor and Nylatron chain drive, with a concrete counterbalance weight (you can see pictures at Gnome Miniature Engineering model railway bridges). The prototype control system was quite sophisticated, with current sensing to detect end of travel, and a slipping clutch to prevent damage. In the end, it turned out that good balance was easy to achieve and a very small motor was all that was needed. It was a 12VDC motor, but 5V was more than adequate, and a mobile phone charger with a reversing (DPDT) switch and a push button powered it perfectly well at a small cost. DCC would probably have worked quite well, but we didn't get that far. (I still have some drive system components, so if anyone is interested, let me know - the price will be quite modest!)

I also built one 1.5m span special to a similar design for a customer, but soon wished I hadn't. The mass of the counterweights was enormous, and it was a mechanical dinosaur.

Andrew
 
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