Why is the HL (Hard Lock Nut) Resistant to Loosening?
This is because when fastened, the Hard Lock Nut produces stress both in the direction of the axis and in a direction perpendicular to the axis. Firstly, the convex fastening nut generates axial torque in the same way as a normal nut. Then, as the concave lock nut is tightened, the wedge effect generates stress perpendicular to the axis, which pushes the convex nut against to the screw thread. When the concave nut is completely tightened, the HLN produces a stable self-locking force by means of the combined stresses of P1 + P2 + P3 (in the figure above), with the result that it remains unaffected by the external vibration or impact.
