Technical Data

1. Hardness differences between HEICO-LOCK and mating surfaces (HHEICO > HMaterial)

• The hardness of the Heico-Lock washer should not exceed the hardness of the mating surfaces and is higher than structural grade and high tensile bolts and nuts (8.8, 10.9 and 12.9.

  Radial teeth/ridges on the outside of the washers grip into and seat the mating surface in the tightening process.

HEICO-LOCK Hardness table

2. Difference in the rise of HEICO-LOCK cams and the pitch of the bolt

• The rise of the cams α between HEICO-LOCK wedge locking washers is greater that the pitch β of the bolt.
• The elongation of the thickness of HEICO-LOCK wedge locking washers is larger than the potential movement of the bolt along the pitch. The locking washer prevents the bolt/nut from loosening due to vibration and the bolt/nut is locked safely in place.

3. Differing Friction Coefficient between HEICO-LOCK cams und 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.

4. Securing the bolted joint through post tensioning (Fdyn > Fstat)

• Loosening the bolt causes the pair of HEICO-LOCK wedge locking washers to expand, thus actually increasing the clamping force. The result is an increase in the clamping force.

• The expansion of the pair or washers increases the pre-load and locks the fastener securely, even when subjected to extreme vibration and dynamic loads.

5. HEICO-LOCK wedge lock washers with a large outside diameter

Large I.D. HEICO-LOCK wedge locking washers are recommended for use on large/long holes (for example with flange nuts or screws), painted surfaces or soft materials, for example. aluminum.