Tuesday, July 14, 2009

Coupling pt II

After the last post I've had time to have a bit more of a think about the whole problem (another WTF moment, if you will). An idea crystallised after looking at Pats non working NZR couplers (or coupling bar), as well as thinking about the British tension lock system, and my own first forays into NZR modeling where pocket money didn't extend to fancy couplers. Hence the following was born.

"Da da da Dum"

I had some 1.6mm square brass tube which provided the base. One piece had a hacksaw cut made in it to a depth of ~2mm. I then soldered (yes, soldered!) some 0.25mm brass sheet squares to the ends, and used a file to round them off. A gap was filed in the top of the disk to allow a coupling hook to fit. A coupling hook was folded up from brass wire, and after being bent to a slight hook shape was soldered on the end without the hole in the shank.

A brass crass brace was soldered on and then the assembly's were attached to the wagons for testing.

The coupler will push and pull happily round a 15" radius curve, and probably a bit tighter. the slight reverse curve in the coupling hook means that when there is a load applied the couplers are pulled down towards each other rather than square where there is a possibility that one will lift away from the other.

As a prototype I think it has a fair bit of promise for a non working coupler which makes as least as much sense as anything else we use. There needs to be a bit of work done on the shape of the neck, but its not a huge problem to solve.. Rakes of wagon can have the coupler of your choice at each end. Its not quite as flexible as regards to wagon facings, but you can't have everything.

UPDATE: Darryl has provided an excellent sketch of what I'm talking about.


Anonymous said...

Great concept !

A couple of idle thoughts on the expansion on this basic idea:
i)for the hook use fine sprung piano wire with a small loop formed in the top that can be "picked" by a suitable uncoupling tool (dentists pick perhaps?)to manually uncouple the wagon.

ii)for remote uncoupling: Form the section the hook couples to, from a piece of mild steel and attach it to the wagon body by a springy piece of thin phospor bronze. To uncouple, use the familiar electromagnet between the track which, when energised, would attract the steel down, thus effecting an uncouple.
With careful shaping of the coupling components, this could perhaps even become an auto couple system as well.

But then again, MTs might be easier .....

Motorised Dandruff said...

I guess you could have a crack at this if you wanted. I was just after something that looked right and would allow me to run a 20 wagon block train on my layout.

I'm still not convinced that the physics of the whole setup will allow this to work reliably. There's an invite for someone to prove me wrong.

RKBL said...

Looks Promising, what about a cast one for mass production.