1 HEICO HEICO-LOCK Presentation * Lee Gordon *

2 Limitations of Friction Based Fasteners Joints loosen due to dynamic or vibrating loads Advantages of lubrication not utilized Difficult to achieve adequate or accurate clamping force Often time consuming to assemble (increased costs) Possibility of damaging bolt threads Typically non reusable

3 Advantages of Using HEICO-LOCK Maximum Safety and Security Resists Loosening of Vibrating and Dynamic Loads Ease of Assembly and Disassembly Controllable Preloads No Hydrogen Embrittlement or Chromate Contamination Locking Function not Lost with Lubrication Reusable Positive Locking at Low and High Preload Levels No Special Tool Requirements

4 The rise of the cams α between HEICO-LOCK wedge lock washers is greater that the pitch β of the bolt. Tension and Geometry

5 H HEICO H material 1. Hardness differences between HEICO-Lock and mating surfaces: H HEICO > H material The hardness of the Heico-Lock washer should exceed the hardness of the mating surfaces and is higher than structural grade and high tensile bolts and nuts (8.8, 10.9 an 12.9). Radial teeth/ridges on the outside of the washer grip into and seat the mating surface in the tightening process. Concept of HEICO-LOCK Wedge Lock Washers HEICO-LOCK Hardness Table MaterialSizesZinc-Laminate-FinishNon Coated Standard-SteelHLS-3 - HLS-42 (through hardened)HLB-3 - HLB ±25 HV Stainless SteelHLS-3SS - HLS-42SS (surface hardened)HLB-3SS - HLB-42SS > 520 HV0.05

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

7 3. Differing Friction Coefficient between HEICO-LOCK cams and radial ridges : µ a > µ i μaμa μiμi Concept of HEICO-LOCK wedge lock washers  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

8 4. Securing the bolted joint through post tensioning: F dyn > F stat  Loosening the bolt causes the pair of HEICO-LOCK wedge lock washers to expand, thus actually increasing the clamping force. The result is an increase in the clamping force. Concept of HEICO-LOCK wedge lock washers  The expansion of the pair or washers increases the pre-load and locks the fastener securely, even when subjected to etreme vibration and dynamic loads.  Large I.D. HEICO-LOCK wedge lock washers are recommended for use on large/long holes (for example with flange nuts or screws), painted surfaces or soft materials, for example aluminum.

9 Typical Wedge Lock Washers Application Hexagon bolt in a clearance hole – both sides - secured by HEICO-Lock Hexagon bolt in a tapped hole – secured by HEICO-Lock Stud bolt – secured by HEICO-Lock Countersunk Cylinder Head Screw - Secured by HEICO-Lock

10 Images of HEICO-LOCK Wedge Lock Washers

11 Washers with enlarged outer diameter Large or slotted holes Painted surfaces Soft underlying materials standard enlarged Use together with flange bolts / nuts

12 When HEICO-LOCK should not be used Extremely hard mating surface Soft materials (wood, plastic) or applications with extremely large settlements Mating surface that is not locked in place Do not use on flat washer or surface that can rotate

13 Application examples for wedge lock washers  Industrial Vehicles  Processing Machinery  Mining & Forestry  Wind Power & Turbines  Railway & Transportation

14 Application examples for wedge lock washers  Automotive Industry  Miscellaneous Applications

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19 Contact Us: Heico Fasteners, Inc th Avenue NW Hickory, NC Telephone: Telephone: Others: Website: