cam-lock washers
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© 2012 HEICO Unternehmensgruppe
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© 2012 HEICO Unternehmensgruppe
HEICO-LOCK wedge lock washers
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© 2012 HEICO Unternehmensgruppe
HEICO-LOCK wedge lock washers
The HEICO-LOCK WEDGE LOCK WASHERS consists of a pair
of washers with a wedge-locking action, which is a unique method
that uses tension instead of friction. The key is the difference in
angels. Since the cam angle is larger than the thread pitch, the pair
of washers expand more than the corresponding pitch of the thread.
HEICO-LOCK washers positively lock the fastener in a joint which is
subjected to extreme vibration or dynamic loads.
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© 2012 HEICO Unternehmensgruppe
HEICO-LOCK wedge lock washers
• HEICO-LOCK wedge lock washers offer high quality, high value bolting system
• for demanding bolted fastening applications • a proven fastening system, working at low and high preload levels • a bolt securing system providing exceptional resistance to vibration loosening and dynamic loads – safe in both dry and lubricated conditions.
• Consistent reusability without loss of function and quality
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General Bolt Theory
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Why nuts and bolts are used
Nuts and bolts have great holding power and allow rapid assembly
and disassembly
Relatively low torque can lead to high clamping force which can firmly hold assemblies together
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Two Major Reasons for Failure
Self loosening due to dynamic or vibrating loads improper preloading
Resulting in…• Loss of Clamp Load• Unwanted Movement in Joint• Eventual Bolt Failure
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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
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© 2012 HEICO Unternehmensgruppe
Advantages of using HEICO-LOCK
Maximum Safety and Security
Resists Loosening of Vibrating and Dynamic Loads
Ease of Assembly and Disassembly
Locking Function not Lost with Lubrication
Controllable Preloads
Positive Locking at Low and High Preload Levels
No Hydrogen Embrittlement or Chromate Contamination
No Special Tool Requirements
Reusable
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© 2012 HEICO Unternehmensgruppe
The rise of the cams α
between HEICO-LOCK
wedge lock washers is
greater than the pitch β
of the bolt.
Tension and Geometry
α
β
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• Cams with blocking wedge effect on inner surface of the lock washer, radial teeth on
the outer surface
• Gripping and seating of radial teeth in mating surfaces when tightening
• Stress only appears inside the inner key faces
• Washers already glued in pairs (to avoid assembly errors)
Concept of HEICO-LOCK wedge lock washers
key faces on inner surface radial teeth on
outer surface
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© 2012 HEICO Unternehmensgruppe
2. Angle differnce: α > β
• The rise of the cams α between HEICO-LOCK wedge lock washers is greater than 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 the bolt along the pitch. The lock washer prevents the bolt/nut from loosening due to vibration and the bolt/nut is locked safely in place.
α
β
HHEICO
HMaterial
1. Hardness dfference: HHEICO > HMaterial
• 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
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4. Preload difference: Fdyn > Fstat
• Loosening the bolt causes the pair of HEICO-LOCK wedge lock washers to expand. 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.
• Large O.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.
3. Friction difference: µo > µi
• 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 µo)
• Any loosening through a dynamic load will always lead to movement
only across the face of the cams of the washers
μo
μi
Concept of HEICO-LOCK wedge lock washers
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Examples of appliance of the wedge lock washers
Through bolt- secure on both sides -
Bolt secured- in stud hole -
Stud bolt secured- without glueing -
Allen head screw© secured - in sinkhole -
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Drawing of HEICO-LOCK wedge lock washer (HEICO-LOCK HLS-… , standard)
3D-files also available upon request
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Drawing of HEICO-LOCK wedge lock washer (HEICO-LOCK HLB-… , large O.D. )
3D-files also available upon request
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HEICO-LOCK wedge lock washers product list
…additional sizes as well as other alloys are available upon request.
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Processing machinery
Automotive
Railway
Application examples for wedge lock washers
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Wind power
Agriculture & Forestry
Miscellaneous applications
Application examples for wedge lock washers
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Offshore
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Contact Us:
Heico Fasteners, Inc. 2377 8th Avenue NWHickory, NC 28601 Telephone: +1.828.261.0184Telephone: +1.888.822.5661 Others: +1.828.308.3405 E-mail: [email protected]: www.heico-lock.us