cam-lock washers

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1 © 2012 HEICO Unternehmensgruppe

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Page 1: Cam-Lock washers

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© 2012 HEICO Unternehmensgruppe

Page 2: Cam-Lock washers

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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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© 2012 HEICO Unternehmensgruppe

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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© 2012 HEICO Unternehmensgruppe

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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© 2012 HEICO Unternehmensgruppe

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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© 2012 HEICO Unternehmensgruppe

• 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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© 2012 HEICO Unternehmensgruppe

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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© 2012 HEICO Unternehmensgruppe

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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© 2012 HEICO Unternehmensgruppe

Drawing of HEICO-LOCK wedge lock washer (HEICO-LOCK HLS-… , standard)

3D-files also available upon request

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© 2012 HEICO Unternehmensgruppe

Drawing of HEICO-LOCK wedge lock washer (HEICO-LOCK HLB-… , large O.D. )

3D-files also available upon request

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© 2012 HEICO Unternehmensgruppe

HEICO-LOCK wedge lock washers product list

…additional sizes as well as other alloys are available upon request.

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© 2012 HEICO Unternehmensgruppe

Processing machinery

Automotive

Railway

Application examples for wedge lock washers

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© 2012 HEICO Unternehmensgruppe

Wind power

Agriculture & Forestry

Miscellaneous applications

Application examples for wedge lock washers

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© 2012 HEICO Unternehmensgruppe

Offshore

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© 2012 HEICO Unternehmensgruppe

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© 2012 HEICO Unternehmensgruppe

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