A Roman treadmill crane. The ancient Romans used similar cranes to lift large stone blocks to construct their spectacular building projects. A person (or multiple people) would walk within the wheel and cause the crane to lift heavy loads using pulleys to gain mechanical advantage.
Materials used:
This crane was made exclusively using Mold #220 the Wooden Plank Mold.
A 3/8" wooden dowel
1 small paperclip
1 large paperclip (for the boom anchors)
some 8mm thread for rope.
The statue base is from mold #42 Gothic Arena Accessories.
The statue is a very old one that I had sitting around. It's made of lead so
that should tell you how long I've had it. It was the heaviest miniature I could
find.
The boom of the crane can be raised or lowered by pulling the ropes through the
loops at the back of the crane. The ropes are tied in a simple knot that's easy
for me to undo so I can change the angle of the crane later if I want. Turnnig
the wheel will raise or lower the pulleys that support whatever is being lifted.
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Quicktime movie of the crane in operation
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Here's an overview shot of the crane. A person would walk inside the wheel (like a hamster wheel) and the rope attached to the pulleys would raise the load. Pulleys were used to give mechanical advantage and increase the maximum weight that could be lifted. The boom of the crane can be raised and lowered and the wheel turns to work the pulleys. The miniature is a very old minotaur figure I had that was mead of lead. It was basically the heaviest thing I could find that even remotely fit with the scene. |
| Another shot of the crane where you can see the back. The ropes are just tied off at the iron rings for this model but normally they would have been pulled up or down by animals or people and then fixed using stakes in the ground. Since this was done for the HADD 8 contest and it has a 12" X 12" base limit I didn't have room for much else other than just tying them off. |
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The ropes are made from 8mm thick brown thread I got at Wal-Mart. The shaft that the wheel rotates is made from a piece of 3/8th inch dowel. The pulleys are made from pieces from the Wooden Plank mold with bits of a paper clip for the ropes to travel over. The keeper pins that keep the wheel shaft from moving laterally and the iron rings that are used to hold the boom up are also made from paper clips. |
| Here is a close-up of the pulleys and the miniature they're holding up. The pulleys were made from cutting pieces from the Wood Plank mold then drilling a hold and inserting a piece of paper clip between the pieces. It worked pretty good I think. The ropes slide over the paper clip pieces easily and they look pretty good, if a little big. |
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A shot of the wheel itself. It was made from the big pieces from the Wood Plank mold. The pieces inside the wheel are to give traction to the person walking inside. They also help strengthen the connection between the outside pieces of the wheel. |
| Here's a shot of the wheel mechanism. As the wheel turns it either winds the rope around the shaft to raise the load or it lets the rope out to lower the load. The shaft is glued to the wheel and there are pins on the other side to prevent the shaft from moving laterally as the wheel turns. |
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Here's a close-up of the shaft opposite the wheel. The pins are made from a paper clip that I cut up. The hole was cut through the pieces for the shaft by using a drill bit between my fingers. |
| Here's a shot of the pivot point for the boom. There is nothing attaching the boom to the crane. It is held in place by it's own weight and the tension of the ropes. |
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And finally, a shot of the iron rings that I'm using to anchor the boom. These are really here to redirect the ropes along a horizontal line so they can be pulled by a team of animals but they work good for holding the boom in place with a simple knot. They were made by wrapping a paper clip around a small screwdriver shaft and then cutting the excess off. I used a small drill bit to drill into the model and glued the rings in place. |
Some more shots of the crane.
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