Heico-Lock

Principle of Operation

Heico-Lock washers are a paradigm shift in locking fastener technology. Conventional fasteners often rely on the physics of friction instead tension to maintain clamp load. Hence nylon insert nuts, metal lock nuts, split lock washers, safety-wire, thread adhesives, etc. offer limited performance.

Known as “wedge-lock,” “cam-lock,” or “wedge washers,” the unique tension based design of the washer system provides superior resistance to constant vibration, high dynamic loads and thermal cycling.

Bolt loosening results in both washer halves separating under the bolt head, resulting in an increase in tension and clamp load. During removal, only the cam surfaces move, resulting in low off torque force.

Tension Based Washer Design Principle

The angle of the cams (α) between the HEICO-LOCK washers is greater than the thread pitch (β) of the bolt.

Wedge Lock Washer Dynamics

Bolt loosening results in both washer halves separating under the bolt head, resulting in an increase in tension and clamp load. During removal, only the cam surfaces move, resulting in low off torque force.

Differing Friction Coefficient between HEICO-LOCK cams and radial ridges

The cams on the separation plane (joint face) of the individual washers of the pair show a much lower friction coefficient µi than the friction coefficient on the radial ridges on the outside of the pair of washers µa)

Any loosening through a dynamic load will always lead to movement only across the face of the cams of the washers.