Rubber Band Transmission

thingiverse

This is one of my entries in the #MakerEdChallenge. This project helps kids grasp the fundamentals of speed reduction/increasing. The drive power comes from a rubber band that runs the pulleys. Students can alter the ratio and spin the drive shaft to see the other spin at the ratio of the pulleys. The 1st "gear" has a 1:2 ratio, the 2nd is 1:1, and the 3rd is 2:1. This is an educational toy, so I kept the parts simple. You'll need to print: * 2 stop collars * 2 transmission drive pulleys * 2 brackets It doesn't cost much to print this, but you will also need: * 2 2 1/2 inch long 1/4 in dia. dowels for the axle shafts * 1 rubber band that's tight enough on the pulleys. Print Settings: Printer Brand: RepRap Printer: Prusia I3 Rafts: Doesn't Matter Supports: No Resolution: 0.2 Infill: 20% Notes: Support not needed. Print the pulleys with the biggest one on the bottom. Custom Section: Project: Simple Transmission Objectives: To learn how speed reduction works. Audiences: 2nd-4th grade Preparation: You need to know the basic concept already, but this tool visualizes what you know on paper. You need a printer (of course!), 5 inches of 1/4 wood dowel, and a rubber band. Steps: Print it as a kit and have students put one together as a group. Then they can have one that they can change "gears" and see how it works up close. Results: Students should have a better understanding of how speed reduction works and see what a 3D printer can do!