Wedge Locking Principle of Washers

Washer hardness

The hardness of the washer is not lower than Rockwell Hardness HRC 45, which is higher than the typical hardness range of grade 12.9 bolts (Rockwell Hardness HRC 39-44). This design ensures that when torque is applied, the radial fine teeth can embed into the surface of the fastener and the connected part, as shown in Figures 2, 3, and 4.

Translators：Washers may leave embedded marks on the surfaces of fasteners and connectors, but this does not affect their normal function.

Geometric Principle
After the radial fine tooth of the washer is embedded, it forms a solid integral with the fasteners and connectors. The "wedge angle" formed by the wedge-shaped tooth surface of the washer is designed to be greater than the "thread pitch angle."

Wedge Locking Principle

After the radial fine tooth is embedded, the washer forms an integral unit with the fasteners and connectors. Displacement or misalignment can only occur on the wedge-shaped tooth surface of the washer, causing the washer to thicken and subsequently creating tension between the fasteners and connectors, thus increasing the clamping force.
During disassembly, this is achieved by having the wedge-shaped teeth of the single washer slide against each other.