ICE-Lok™ Thermally Enhanced Wedgelock

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The patented Isothermal Card Edge (ICE)-Lok™ is designed to enhance thermal performance for conduction cooled embedded computing systems. Compared to conventional wedgelocks, the ICE-Lok™ creates additional heat transfer paths from card to chassis, thereby reducing the thermal resistance.

The ICE-Lok™ can be seamlessly integrated into standard VITA systems, creating longer life and higher reliability for your critical components without costly board or chassis redesign.



• 33%+ reduction in thermal resistance from equivalent size COTS wedgelocks, due to added heat transfer paths and surfaces
• Single screw access for easy board installation/removal
• Rugged design and construction as validated through shock/vibration testing and repeated installation cycles
• VITA 48.2 compliant
• Compatible with standard VITA 3U, 6U and 9U cards
• Superior clamping force

Replacing COTS wedge locks with ACT’s 3/8” ICE-Lok™ for a 100W system lowers component temperatures by > 10°C.

Replacing COTS wedge locks with ACT’s 3/8” ICE-Lok™ for a 100W system lowers component temperatures by > 10°C.


Everything you need to know about thermally enhanced wedgelocks

When are wedgelocks used?

Wedgelocks are used when electronics cards must be easily replaceable.  The wedgelock is a mechanical clamp that allows a card to be swapped quickly, but has the drawback of being a relatively poor thermal conductor.  As power per card continues to increase, a lower thermal resistance device is needed.

Wedgelock Comparison

Can an ICE-Lok™ wedgelock help with overheating components?

Yes.  By lowering the thermal resistance by more than one-third, replacing a standard wedgelock with a 3/8” ICE-Lok™, component temperature are lowered by 10°C at 100 W power input.

How do wedgelocks work?

As shown in the figure below left, a standard wedgelock has a series of trapezoidal-shaped wedges, with an internal screw.  As the screw is tightened, the wedges are forced up and down, exerting pressure to clamp the card into the chassis.

wedgelock  ICE-Lok with Integral Brackets

How does ICE-Lok™ lower thermal resistance?

As shown in the figure above right and described in the video below, the ICE-Lok™ improves performance by increasing the surface area for heat transfer and maximizing contact pressure.  The wedges are cut at a bias, so that the wedge can expand in two directions, allowing the ICE-Lok™ to contact all four sides of  the thermal interface.  An integral bracket also reduces the thermal resistance.

Since the ICE-Lok™ expands in two directions, do I need to be concerned with deforming the chassis or card?

Chassis and/or card deformation is not a problem, since the wedges are designed to “Friction Lock”.   The wedges do not apply forces on the chassis or card until the wedges fully contact all four faces. When considering a horizontal conduction card, the bias angle of the wedges is designed so that the friction forces of the vertical load is greater than horizontally.  This generates a friction force greater than the horizontal force and prevents the ICE-Lok from further movement in the horizontal direction. This results in no external deflection of the chassis or conduction card.

Chassis deformation

What tests were used to qualify the ICE-Lok™?

The qualification tests included both thermal and mechanical tests.

Thermal Qualification Testing: The thermal testing procedure is shown in the figure below.  In one set of tests, the thermal resistance was measured initially, and after each 20 card withdrawals/insertions.  No appreciable change was measured.

Thermal Testing Timeline

In the other set of tests, the thermal resistance of the card was measured before and after shock and vibration tests.  The test conditions encompassed military aircraft, Delta IV, and Atlas V.  No problems were observed.

Mechanical Qualification Testing: Mechanical testing consisted of retention testing and shock and vibration testing; see the figure below.  Retention of the card under an applied for of 300lbf is necessary for qualification.  Card retention was tested on a dedicated chassis, then shock and vibration testing was performed, followed by additional retention testing.  The test conditions encompassed military aircraft, Delta IV, and Atlas V.  No problems were observed.

Mechanical Testing

How do I know the ICE-LokTM will fit in my chassis?

In order to get the thermal benefits of ICE-Lok™,  both the Card Guides and Conductance Card need to make physical contact with ICE-Lok™, and by extension with each other.

Our ICE-Loks™ are designed to fit within chassis made to VITA standards.  The downloads below can be used to help size the thickness of the conduction card flange.  This way the card/ICE-Lok™ assembly will be sure to fit within your chassis.  However, the ICE-Lok™ won’t expand indefinitely.  Maximum limitations for each model can be found on the product data sheets and on each .STEP file below.

A.250-09 .STEP file

B.250-09.STEP file

A. 375-05 .STEP file

B. 375-05B.STEP file

A.375-07 .STEP file

B.375-07 .STEP file

Get your quote today

Now that you’ve learned what a wedgelock is and how they are used, it’s time to contact ACT for more information and a quote for improving your equipment’s thermal conductivity and efficiency. We will help you decide how best to meet your needs.

We’ll provide you with everything you need to understand the cost of the ICE-Lok™ solution as well as the options that will replace your current wedgelock.

Reduce your costs and improve the life and reliability of your equipment with a simple conversation designed to make your operations easier and affordable. Contact ACT today to learn about all of your thermal management and other energy recovery options.


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