The Nexen Ball Screw Brake is a high-torque, spring-engaged brake acting on the machined end of a ball screw. It serves as a primary or redundant safety brake to prevent back driving if a power loss or mechanical defect occurs in the driveline. The low backlash and coupling combination provides a high degree of accuracy for holding ball screw position. An expanding shaft/clamping hub coupling connects the brake shaft to the end of the ball screw. This coupling comes with an elastomer insert with high torsional stiffness.