The CORE Bearing combines three COREs (compliant rolling-contact elements) into a compact mechanism that provides near-constant torque across a large angular displacement. It was designed to be a prosthetic knee, providing rotation with a built-in restorative spring, as well as high resistance to radial loads pulling on the center. It also happens to look like a fidget spinner.

Printing Instructions

We recommend allowing the print time to cool before attempting to actuate it, as the thin compliant segments are very susceptible to stress relaxation, especially while warm. Meaning, if you try to rotate it too soon after taking it off the printer, it will loose its springiness very quickly. This model doesn't require any special settings to print; a standard printer with a 0.4mm nozzle should suffice.

The .STL version of the model works fine, but has slightly noticeable angle discretization. We recommend printing from the .STEP file instead to get around this.

When printed, grip the center disk firmly with the right hand, and rotate the outer ring of the model counter-clockwise with your left hand.

Technical Information

Check out the research paper behind the CORE Bearing here: [https://www.mdpi.com/2075-1702/14/6/600](https://www.mdpi.com/2075-1702/14/6/600)

And here's the original CORE paper, discussing the rolling contact joints: [https://asmedigitalcollection.asme.org/IDETC-CIE/proceedings-abstract/IDETC-CIE2004/46954/689/306419](https://asmedigitalcollection.asme.org/IDETC-CIE/proceedings-abstract/IDETC-CIE2004/46954/689/306419)

Intellectual Property

The downloadable 3D print files provided here may be used, modified, and enjoyed for noncommercial use. To license this technology for commercial applications, contact:

BYU Technology Transfer Office 3760 Harold B. Lee Library Brigham Young University Provo, UT 84602 Phone: (801) 422-6266 [https://techtransfer.byu.edu/contact](https://techtransfer.byu.edu/contact)