Expandable Locking Mechanism for PCB Thermal Conduction
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Solution Overview
Problem
Current electronic card designs require two different printed circuit formats for convection and conduction cooling modes, necessitating costly and error-prone cutting of edges, which complicates conversion between cooling modes and limits compatibility.
Innovation Solution
An electronic card with a flat printed circuit and a heat sink, featuring expandable locking means with a motion transmission part and a movable part that includes a recess, allowing the card to be immobilized in a frame and pressed against it, enabling both convection and conduction cooling without edge cutting, and accommodating a single printed circuit format for both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard locking mechanism is used for conduction cooling, then the heat sink can be pressed against the chassis to enable thermal conduction cooling, but the printed circuit board edges must be cut which increases manufacturing complexity and reduces adaptability
Solution Approach 1:
The locking mechanism is designed to serve multiple functions: it provides thermal conduction cooling when engaged with the chassis, and simultaneously acts as a mounting structure that does not require PCB edge cutting. The recesses in the locking mechanism's movable part allow it to engage with corresponding areas on the PCB without requiring edge modifications, enabling the same mechanism to support both cooling modes.
Solution Approach 2:
The locking mechanism is divided into distinct functional parts: a motion transmission part that receives actuation force, and a movable part with recesses that contacts the PCB. This segmentation allows the mechanism to provide thermal conduction through the heat sink while the recesses accommodate the PCB areas without requiring edge cutting, thus maintaining adaptability.
2Ease of manufacture
If the printed circuit board is cut to accommodate the locking mechanism, then the locking mechanism can be installed for conduction cooling, but manufacturing precision requirements increase and the risk of cutting residue spreading increases
Solution Approach 1:
The invention extracts the requirement for PCB edge cutting by designing the locking mechanism with recesses that engage with areas on the PCB surface. This eliminates the need for precise edge cutting while still allowing the locking mechanism to be installed and function properly for thermal conduction cooling.
3Ease of manufacture
If the printed circuit board is cut for conduction cooling, then the locking mechanism can be installed, but the board area for track or component positioning is reduced
Solution Approach 1:
The locking mechanism with recesses serves as a universal solution that provides mounting capability without requiring PCB edge cutting. This preserves the full PCB area for track routing and component placement while still enabling conduction cooling through the heat sink and locking mechanism assembly.
4Reliability
If two different PCB sizes are manufactured for convection and conduction cooling, then each cooling mode can be optimized, but manufacturing and storage complexity increases
Solution Approach 1:
The locking mechanism is designed to work with a single standard PCB size for both convection and conduction cooling modes. The recesses in the movable part engage with areas on the PCB without requiring different PCB dimensions, allowing the same PCB design to be used across both cooling modes and eliminating the need for separate manufacturing and storage of different PCB sizes.
Solution Approach 2:
The locking mechanism transitions between different operational states: in convection mode, the heat sink is positioned for air cooling; in conduction mode, the locking mechanism engages with the chassis through the recesses to provide thermal conduction. This dynamic adaptability allows a single PCB design to support both cooling modes without requiring physical modifications.
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
Enables a single printed circuit to be compatible with both convection and conduction cooling, reducing manufacturing and storage needs, simplifying conversion between modes, and enhancing the circuit's dimensions for improved heat exchange and component placement.
Implementation Method 1
Thermal conduction is a mode of heat transfer resulting from a temperature difference between two areas of the same medium or between two different media in contact. Thermal conduction cooling is sometimes preferred to convection cooling in harsh environments, particularly for reasons of reliability (no moving parts such as a fan) and protection against contaminants (dust, etc.).
Implementation Method 2
The pressure of the heat sink against the cold medium ensures good contact and therefore efficient heat exchange.
Data Source
Figure 1~2
Figure 3~4b
Figure 4c~7
AI summary
According to the invention, the electronic board (22; 24) comprises a flat printed circuit board (110; 210), a thermal drain (113), and an expandable locking means (111, 112; 211, 212) positioned along an edge of the printed circuit board (110; 210) comprising a motion transmission portion (116, 118) and a translationally movable portion (117) about an axis (31, 32, 33) including a component perpendicular to the printed circuit board (110; 210). The translationally movable portion (117) has at least one recess (131; 231, 232, 233) opening onto a face (139) of the expandable locking means (111, 112; 211, 212) perpendicular to the printed circuit board (110; 210). The locking means (111, 112; 211, 212) is intended to immobilize the card (22; 24) in a chassis (104) and to press the thermal drain (113) against a face of the chassis (104).The printed circuit board (110; 210) includes an area (141, 142, 143; 241) which fits into the recess(s) (131; 231, 232, 233) of the expandable locking means (111, 112; 211, 212).