A while ago I introduced my factory layout and mentioned that I was thinking of a working hopper feed to automatically load open wagons. This is an historic article, folks - the first with moving pictures! - EH

One of the main problems I had wasn’t, surprisingly, to do with getting the hopper discharging, but rather getting it to stop. I’ve tried simple slide mechanisms, flaps on levers and so on, none of which would shut off the flow properly - the mechanics simply weren’t man enough to force the grit out of the way.

The following details the construction of the “business” end of the feeder.

The external structure can be anything you like as long as your hopper medium is funnelled into it.

First off you need a motor and gearbox unit (Maplins have these in the UK - MFA Multi Ratio Motorgearboxes) as per the following photo

1. Then you need a mini paint roller, the hairy type as used for emulsion paint (I think).
2. Alter the gearbox unit by repositioning the spacer stud and adjust the gearing to suit - I removed all the freewheeling gears.
3. Cut a section off the roller to fit inside the frames of the gearbox allowing for the sides of the chute.

4. Fit roller section onto output shaft. I glued two spare gearwheels to the ends of the roller.
5. You now need to form a chute from styrene sheet, around the roller, on the inside of the gearbox frame. The sides parallel to the output shaft must be positioned to press on the roller slightly so it effectively rubs against them. This prevents any ‘leakage’.
6. The third diagram above shows the basic operation. The roller effectively “sweeps” the grit through the hopper. All you need do now is switch the motor on when you want to feed, switch off to stop. I’ve configured reed switches on the hopper legs and magnets in the wagons to do this automatically via a relay.

Photographs and plans © Steve Welch

Interestingly, you don’t need to mechanism to be vertical for it to work, so you could use it to feed a hopper coming out of a wall at 45 deg say. I’ve tried it with grit ranging from sand upto chippings around 2mm diameter with no adverse effects.

And now the bit you’ve been waiting for - The Movie!

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