Wedge Based Circuit Board Retainer Thermal Management
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Solution Overview
Problem
Existing card retainer systems for electronics in harsh environments face inefficiencies in heat dissipation and structural clamping force, particularly in high heat load situations, due to reliance on central support members that limit thermal energy flow and mechanical stability.
Innovation Solution
A card retainer system with movably linked wedge members that expand vertically without a central longitudinal element, utilizing guide straps to connect adjacent wedges and increase cross-sectional area for enhanced thermal transmission and clamping force, eliminating the need for a central support member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a central support member (long bar, screw, or shaft) is used to connect and align all wedges, then the structural alignment and mechanical stability are improved, but the cross-sectional area for thermal energy flow is reduced and heat dissipation efficiency deteriorates
Solution Approach 1:
The patent removes the central support member (long bar, screw, or shaft) that previously extended through the center of all wedges. This extraction eliminates the obstacle to thermal flow while maintaining wedge alignment through alternative means (wedge geometry and friction). The removal of this central element directly increases the cross-sectional area available for thermal energy transmission from the circuit board to the chassis walls.
2Force
If wedges slide onto one another at a 45° angle to create clamping force, then the mechanical retention force is improved, but the effective height expansion creates increased friction that may interfere with module removal
Solution Approach 1:
The patent employs dynamic wedge members that can slide relative to one another during insertion and removal operations. The wedges are designed to expand the effective height of the assembly during insertion to create retention force, then allow controlled movement during removal. This dynamic behavior enables the system to adapt its mechanical properties based on the operational phase, providing both secure retention and ease of removal.
3Adaptability or versatility
If the card retainer provides both clamping mechanism and thermal pathway functions, then the device integration is improved, but the structural complexity increases
Solution Approach 1:
The card retainer is designed to perform multiple functions simultaneously: it provides mechanical clamping force through the wedge mechanism while also serving as a thermal conduction pathway from the circuit board to the chassis walls. The wedge members themselves are configured to conduct thermal energy, eliminating the need for separate thermal management components and reducing overall structural complexity despite the multi-functional requirement.
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 design improves thermal energy flow and mechanical stability by increasing the cross-sectional area for heat dissipation and clamping force, effectively addressing the limitations of prior systems in high heat and vibration environments.
Implementation Method 1
Typically card retainers use a series of ramps or wedges that are forced to slide onto one another to clamp the LRU to the chassis. The wedges slide onto one another at an acute angle, typically at 45°. The action of the wedges sliding one above the next create an expansion of effective height of the total assembly which creates a frictional force that holds the LRU in place
Implementation Method 2
In addition to providing a clamping mechanism to retain the module, a card retainer in a conduction cooled application can also provide an efficient method of transmitting thermal energy from the module to the walls of the enclosure
Implementation Method 3
The action of the wedges sliding one above the next create an expansion of effective height of the total assembly which creates a frictional force that holds the LRU in place
Data Source
AI summary
A locking retainer for retaining an electronic module or printed circuit card in slots of a chassis. The retainer includes at least three wedge members movably linked to each other and disposed in longitudinal sequence along a longitudinal axis. The retainer can be made relatively smaller in height by moving the wedge members longitudinally such that a longitudinal distance between a first wedge member and a last wedge member of the sequence becomes smaller without the wedge members being longitudinally displaced along a common internal longitudinal element. All portions of the locking retainer that the middle wedge member is longitudinally moveable relative to do not extend through a theoretical plane disposed at a longitudinal midpoint of the middle wedge member and oriented normal to the longitudinal axis. The elimination of a central rail permits the wedge segments to have much greater contact area for greater thermal energy flow.