Loading chute

[Stefan Krebs]

The other question was how to meter a bulk load, e.g. the load of a standard gauge waggon, or from a bin, into a narrow gauge waggon.

Shutters and flaps, the most commonly seen options on model layouts, are not very reliable and accurate as the metering is done by the operator, and hence the quality strongly dependant on operator skill and expertise.

Conveyers, running on a timer, would be the obvious answer, weren't it for the fact that Hornby, Faller and Vollmer conveyers are big enough to run 009 trains on; - way to big for loading 009 bulk carriers. Only Arnold produced a conveyer small enough to meter into anything the size of the ROCO or Jouef Decauville v-tips. Unfortunately this item is long out-of-production, and even in the bay of 2nd hand rare as hens' teeth.  :'(

But no need to fret, there are other options:
1. Auger feed (Archimedian screw); make it by winding a (preferably rectangular square-section) wire into a spiral and run it inside a metal tube. It needs to be a very loose fit as otherwise it'll jam. The diameter of the tube should be greater than 4 times your particle size, the spiral at least 2 times particle diameter, otherwise jamming can occur. The length is limited by the stiffness of your wire, you want it to transport away from the motor, which causes it to slightly increase in diameter as it fights the friction. With an adjustable timer very accurate metering can be achieved.
2. Vibrating feeders, they come in 2 versions: throwing and sliding.
2.1 If you place a trough (with 1 end open) on springs you can get it to vibrate with an electric magnet. If the (leaf-) springs are vertical the trough will move forward and backwards along its length. With the floor stepped like tiles on a roof the edge will push the material forward, while the fast action of the solenoid will pull the chute backwards fast enough to break adhesion, i.e. make the trough slide back underneath the material.
2.2 Alternatively, with springs angled at about 40 degree from horizontal, the trough will move diagonally upwards and forward. If the magnet and the springs are strong enough, it will send the material 'flying' forward (just a little bit), while the solenoid pulls the trough back underneath. Somewhat more challenging to build.
Both these options are obviously suitable to make material flow down chutes. Accurate metering is achieved by timer controlled runtime.
The Lionel (0-gauge) milk wagon and loading ramp moves its milk churns using this technology, i.e. it's not just for bulk cargo. ;D

I would be cautious with metering wheels (sort of waterwheel in reverse, each pocket containing one dose) as I don't know a way of making these without the risk of seizure. Likewise shutters ad flaps are prone to jamming. Neither of these provide reliable metering, even with timer control.

Last, not least, a crane with suitably sized clamshell does meter too, but 'hitting' the skip might be a bid hit and miss. :laugh:

Kind Regards
Waldschrat