Monday, 21 October 2013

Remote Unloading

With loads that can be popped into the wagons while hidden under the hopper, I need a way to unload them at the other end of the line - inside the tipping shed. Of course the other end of the line is the far corner of the board - OK, it's only about 3 feet away, but out of reach from the operating position, so how can I do it remotely? You might be expecting something clever, mechanised, automated, finely engineered ... you may be disappointed!

I made up a lever with a cross-bar from offcuts of plastic sprue and plasticard, with a neodymium magnet at each end of the cross-bar. This was meant as a mock-up ahead of making something stronger from bits of rail and copperclad board, but it worked fine as it was! The lever is mounted into the centre of a couple of chutes made of plastic, pivoted on a paper-clip wire, and has a length of steel wire fixed to the bottom end, a coating of graphite lubricant for Kadee couplings keeps it all moving smoothly.

This chute contraption is mounted into the board next to the track inside the tipping shed. From below you can see the steel wire-in-tube curving round to meet a wooden dowel, to which it is attached using an electrical choc-block connector, the screw is an end stop to limit movement. The dowel runs across the board to poke through the fascia next to the switch panel, the off-cut of MDF seen here is a more solid mounting than the foamboard.

Having considered gears and levers and even motors, I settled on this as the easiest method, and amazingly it works! About an inch of travel of the operating rod moves the lever through a little over 90 degrees.

So this is the view from behind the back-scene as a train enters the tipping shed, note the essential "buffer stop" (every millimetre of this layout counts so the loco is run against the stop). On the left is the chute and the lever is about half-way down through its arc towards the wagons.

Looking from above (shed roof removed), once the lever has touched the tops of the wagon loads when pulled up brings them with it - remember the small magnets set in their top? When the lever reaches the top of its travel the cross-bar recesses into the "hoods", which push the loads off the magnets, whereupon they drop down the chutes.

All that is then required is to collect them in a tub, and repeat... I made up 5 pairs of wagon loads, so the process can run for a good, er, 5 minutes. Fortunately I can reach the tub to retrieve them from the operating position!

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1 comment:

Phil Parker said...

This is what I love about little layouts - agricultural engineering and a little bodging does the job. This looks really clever and sinc it works, it's as good as it looks!

Love it.