Double Cardan Shaft

grabcad

This setup incorporates two U-joints connected by an intermediate shaft, with the second joint timed opposite to the first to offset altering angular velocity. In this arrangement, the rotational speed of the driven shaft will correspond to that of the driving shaft when both are set at equivalent angles relative to the central shaft (not necessarily in the same plane) and the U-joints are 90 degrees out of sync. This assembly is commonly used in rear-wheel drive vehicles, where it's referred to as a driveshaft or propeller shaft. Note that dimensions may not be precise, so this animation serves only for demonstration purposes. For higher quality animations, visit http://imgur.com/a/uGjZc.