High-Pressure Card Locks for Electronics Heat Transfer
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Solution Overview
Problem
Conventional card locks fail to achieve optimal heat transfer from electronics cards to card cages due to non-uniform and low-pressure contact, resulting in high thermal resistance at the card-chassis interface, which restricts the use of more powerful electronics cards.
Innovation Solution
The development of high-pressure card locks using inclined wedges with low friction interfaces and robust materials, applying uniform pressure of at least 85 psi along the card-chassis interface to enhance heat transfer efficiency, where the card lock itself does not need to be highly thermally conductive as the primary heat flow is through the direct card-chassis interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional card locks are used to secure electronics cards in a card cage, then the cards are held in place, but the contact pressure between the card and heat dissipating chassis is non-uniform and low, resulting in high thermal resistance
Solution Approach 1:
The patent changes the pressure parameter from conventional low and non-uniform pressure to high and uniform pressure (at least 85 psi) through the use of inclined wedges. This parameter change directly reduces thermal resistance at the card-chassis interface, enabling higher heat transfer rates without requiring redesign of the chassis or heat rejection system.
Solution Approach 2:
The patent applies local quality by creating a specialized high-pressure interface zone between the card lock and the electronics card. The inclined wedges concentrate force locally at the card-chassis interface, ensuring uniform high pressure exactly where thermal contact is critical, while other parts of the system maintain their original design.
2Temperature
If the chassis or heat rejection system is redesigned to improve heat transfer, then heat dissipation performance increases, but the cost and difficulty of implementation increase significantly
Solution Approach 1:
The patent introduces an intermediary component - the high-pressure card lock with inclined wedges - that mediates between the electronics card and the heat dissipating chassis. This intermediary applies uniform high pressure to optimize thermal contact without requiring any modification to the chassis or heat rejection system, avoiding the high costs and complexities of redesigning these core components.
Solution Approach 2:
Instead of redesigning the chassis structure or heat rejection system, the patent changes the pressure parameter at the card-chassis interface through the card lock mechanism. This parameter change achieves improved heat dissipation performance through a low-cost, easily manufacturable solution that modifies only the card lock component.
3Reliability
If conventional wedge locks are used, then the card is secured in the card slot, but the pressure distribution is non-uniform and thermal contact is insufficient
Solution Approach 1:
The patent changes the pressure distribution parameter from non-uniform (conventional wedge locks) to uniform (inclined wedges with low friction interfaces). This uniform pressure distribution ensures consistent thermal contact across the entire card-chassis interface while maintaining reliable card securing, resolving the trade-off between mechanical retention and thermal contact quality.
Solution Approach 2:
The patent employs composite materials in the card lock design, combining robust materials with low friction interfaces (such as PTFE coatings or composite wedge structures). This composite approach enables the wedges to generate uniform high pressure while minimizing friction, thereby improving both card securing reliability and thermal contact quality simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly reduces thermal resistance at the card-chassis interface by 7-fold, allowing for more efficient heat dissipation and enabling the use of more powerful electronics cards, while maintaining uniform pressure and structural rigidity, thus overcoming the limitations of conventional wedge locks.
Implementation Method 1
a card lock wherein the card lock is engaged in the at least one card slot so as to force the electronics card into firm contact with the thermally conductive sidewall so that pressure of the electronics card against the thermally conductive sidewall is at least 85 psi (0.59 MPa) along substantially the entire length of the portion of the card lock in contact with the electronics card
Data Source
AI summary
Card locks for securing electronics card in card slots within cages and designed and configured to allow each card lock to impart high uniform pressure between an electronics card and the corresponding card slot to maximize heat transfer from the electronics card to the card cage to efficiently sink heat generated onboard the electronics card. In some embodiments, a high-pressure card lock of the present disclosure has a pair of low-angle wedges and a locking mechanism that effectively pushes one of the wedges along the other wedge to put the high-pressure card lock into its locked, high-pressure-exerting state. In other embodiments, a high-pressure card lock of the present disclosure has a pair of low-angle wedges and a locking mechanism that effectively draws one of the wedges along the other wedge to put the high-pressure card lock into its locked, high-pressure-exerting state.