A LEGO Rotary Hopper Dumper

Designed and built by John Koob

Automated with NQC

Featured at NALUG's GETS 2004 layout

Rotary Hopper Dumper The rotary hopper dumper was built entirely out of LEGO by John Koob. It first appeared at the Great Edmonton Train Show in September 2003. It dumps hopper cars without decoupling and no Lego parts were modified for this functional model. This NQC code automates the dumping procedure.
Picture An image of a model of a rotary dumper was the inspiration for this project. Kudos to Kevin Maynes for asking me to build it and providing some background material. I also found information on actual rotary dumpers, as well as a page about a larger version that can dump multiple cars.
Other model railroaders have built some rotary dumpers, but this has never been done in Lego to my knowledge.
Picture A brown hopper dumping beans into the pit.
Dumper Movie #1

Dumper Movie #2

Two mpegs of the LEGO train car dumper in action. The first shows the car being clamped in place and the barrel rotating, dumping the bricks in the hopper. The second shows the car being returned to the horizontal position.
Picture A light grey hopper is clamped before the dumping mechanism engages.
Picture Tipping over as the dumping procedure continues.
Picture The light grey hopper is rotated to dump the contents.
Picture The pit below the hopper dumper collects "coal ore". We used black beans as ore.
Picture An action shot of a black hopper rotating on the axis of the magnetic LEGO train couplers.
Picture Another hopper emptying coal. The beans just land into to the pit and accumulate to be emptied out later.
Picture Another shot of the rotary dumper tipping over a hopper. The yellow tanker remains coupled to the hopper during the entire dumping procedure.
Picture The barrel rests in a cradle and is powered by a 9V motor on the right.
Picture The rotary hopper dumper is sized to dump the hoppers built by Kevin Maynes. Building plans for Kevin's hoppers are available. By coincidence, the hoppers are close to the length of two 16-stud LEGO track sections.
Picture Construction details of the frame of the barrel.
Picture Another view of the barrel frame under construction.
Picture Black Technic beams provide strength for the barrel frame.
Picture A closeup of the the barrel.
Picture Top view the barrel under construction.
Picture The barrel looks like this when rotated by 90 degrees. Someone cleverly held this up while this shot was taken.
Picture Curved Znap parts connected together serve two purposes. The donut-shaped disk acts as an end wall of the barrel with a suitable diameter for 8-wide train cars. The rims of the barrel each ride on a drive wheel and three free-spinning wheels.
Picture The clamp motor mount. The motor is inverted to simplify the attachment of the LEGO wire connector.
Picture The barrel is nearly complete. The clamp motor is under the tracks and runs all four clamps. Each clamp surface is made using the rubber part from set number 6473.
Picture This view shows the rack gears on two of the train car clamps.
Picture A top view shows how the barrel has dual symmetry.
Picture The second truss has been added and the barrel is now complete.
Picture The bottom view shows the motor driving a worm gear with a red belt. This drives axles that connect to 8-tooth gears beside each of the four light-grey clams.
Picture The barrel rests in a cradle, which is just a pit lined with white bricks. A black hopper is nearby.
Picture The barrel and cradle with the black hopper in position. The cradle also supports two track sections so that they maintain proper alignment with the barrel's track when the barrel is horizontal.
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