Oldham coupling

grabcad

An Oldham coupling features three discs - one connected to the input, another to the output, and a central disc that's linked to both via tongue-and-groove joinery. The grooves on each side are perpendicular, enabling the middle disc to rotate around its center at the same speed as the input and output shafts. This disc traces a circular path twice per rotation, centered between the two main shafts. Springs often provide backlash reduction in this design. A key advantage over two universal joints is its compact size.