Couplings transmit power perfectly — when shafts are perfectly aligned. Flawed installations cause parallel and angular offsets leading to vibration and fatigue, not to mention preload stresses and drivelinebearing friction wear. That’s why most couplings today buffer at least some misalignment. But now there is a coupling that is especially forgiving of installation inaccuracies, without using a looser fit. Compared to similarly sized couplings, this design doubles angular-offset capabilities and increases parallel-offset capabilities tenfold.

Elbow room

Recirculating balls provide for very fine motion as long as they don’t bump together. But in regular ballnuts, balls tend to back up into their neighbors, increasing friction and idling torque. Worst-case scenario, this can lead to servo-loop control instability. Elastic spacers, already common in linear guideways, can help ballscrews avoid these problems by freeing each ball to deliver smooth motion during intermittent strokes. Even better than flexible ball chains (which have a hard time snaking around corners in nuts), the compliant elastic spacer system also accommodates quick direction changes