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The PulleyBot is a simple, single actuator 3D printed toy with a transmission entirely made up of pulley systems. This instructable is a tutorial on how to assemble the PulleyBot, but if you are interested in pulley, cable, and chain mechanisms, then I would suggest checking out this Pulley Mechanisms Instructable. I hope you have fun building this, and even more fun designing your own!

Step 1: Why PulleyBot Works

PulleyBot is entirely driven by belt and pulley systems, which are a type of mechanical transmission. A belt is basically a loop of material, be it a bike chain, a rubber band, or a tank tread, that can be used to transmit mechanical power. It is looped around sets of pulleys, which are simply wheels with grooves or teeth in them for the belt to catch on. As a pulley rotates about an axis, it drives the belt via friction between the belt's surface and the groove of the pulley. This in turn drives the other pulleys linked to the same belt. PulleyBot is a simple system composed of multiple belts and pulleys rotating multiple axes to drive the robot forward.

<p>Thanks printeraction for the Instructable! I plan on using it to teach my students pulley mechanisms. Unfortunately, I can't get it the bot to move forward. I've greased the axles and 3D printed a slightly reduced length of the small drum. I think there are 2 problems. With the motor off, when I rotate the large drum by hand, the O-Ring slips under the large drum so the small drum does not move. Second, the large drum rod shaft often rotates inside the large drum with the motor on. Should I glue the shaft to the large drum? What about a smaller diameter O-Ring? Any suggestions would be most helpful.</p>
Huh, that's odd - Yea, I would try smaller diameter or thicker (or both) o-rings, and definitely glue the shaft to the large drum. Are you using a D profile shaft?
<p>Yes, I am using your recommended D-Shaft. I glued the shaft to the large drum and replaced the O-Ring with McMaster-Carr size 225 ID 1 7/8&quot; ( the original was size 226 ID 2&quot;). Both sizes have width 1/8&quot;. I am happy to report the bot moves about 7-10 cm without getting stuck. Based on your comment, I am going to try a 3/16&quot; width, 1 3/4&quot; ID, 2 1/8 &quot; OD, which is size 327. I'll let you know how it works out. Thanks!</p>
<p>Size 327 did not work, but size 224 did - 1 3/4&quot; ID 2&quot; OD. Success!</p>
<p>First: thank you for the instructable.</p><p>But I've got problems with the 3D prints. I'm using cura and I've to rotate each model. Cura is opening is model on their side and I can't fix the drive wheel. How can I fix this or is it possible to create new files? </p>
Hmm. Interesting. The model should open up with a face parallel to one of the origin planes. I've never used Cura before; are there rotation tools that you can use to tilt the model or a &quot;lay flat&quot; button that will lay it along the build plate?
<p>The image I uploaded is after rotating the model. The file opens perpendicular to the building plate. What program do you use? Maybe I can open it with that.</p>
<p>Hmm. I used MakerBot Desktop, but it only works for MakerBot printers. Are you sure you can't rotate the part by 90 degrees to get it to lay flat?</p>
<p>Ok, I finally managed to rotate the wheel. I imported it in sketchup and rotated there. </p>
<p>Great....Which software your used to make 3d parts</p>
<p>Thanks! I used Autodesk Fusion 360, it's fee for students!</p>
<p>*free</p>
<p>Cute little bot! The shapes are really pleasing, I think it's all the soft edges.</p><p> If I had access to a 3D printer I'd make a &quot;double barreled&quot; version with one pulley set driving each side, then it could steer! Of course, one could do it without a 3D printer, I do have a stack of gears left over from disassembled 2D printers... ;-)</p>
<p>Nice idea! You could also upcycle some other things to make your own pulleybot: Wooden or plastic thread spools work great for small pulleys, among other things!</p>
Really cool I hope you make more things like that.
<p>This is an excellent work of 3D printing and design. I really like how you switch planes with the pulleys. Keep it up!</p>
<p>Thanks! I hope to be publishing some more fun, simple 3d printed transmission stuff soon!</p>

About This Instructable

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Bio: My name is Alex Crease, and I'm an engineer, a musician, and an adventurer. I love building things and taking others apart to see ... More »
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