Physics Rotation Pulley

thingiverse

This project turns a MakerBot filament spool into a physics rotation pulley. The pulley is designed to be used in physics classrooms to showcase concepts such as rotational inertia and simple pulley systems with weights. The large size of the spool/pulley makes it ideal for these labs as it is "massive" and has a larger radius than the typical physics pulley. It is a cheaper alternative compared to purchasing large pulleys (example: a Bicycle wheel) and it also reuses empty filament spools. The 3D printed clamps are designed to fit over the outside of the MakerBot spool and clamp into the notched sections in the center. The clamps hug the outside of the wheel and bridge the gap between the two edges. Although it is a little difficult to put on (it requires a little bit of bending), the clamps should fit securely. In order to save material, a notch was cut into the flat sides of the clamps. The Sector Bridges bridge the gap in between the Sector Clamps. These were created to help extend the groove all the way around the wheel, preserving the pulley's curvature. Otherwise, once the string is wrapped around the pulley, the string would lay flat in between the clamps. The bridges are held in place due to the natural "sector geometry" of the clamps (the angled sides prevent the bridge from falling in, and the lip under the bridge prevents them from coming out). No glue is required to secure the bridges. The pulley will rotate around a 0.5in diameter rod. Ball bearings must be purchased and can be found here (https://goo.gl/yAuPv8). The bearing piece is held in the center of the pulley by a single plug via friction fit. The plug has 3 tongues which fit into the 3 slots which are not used by the clamps. Ball bearings will be held via a tight fit from the plug,