Metal Push Pin Fastener for Heat Sink Mounting
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Solution Overview
Problem
Existing push pin fasteners for securing heat sinks to printed circuit boards are prone to breakage due to abrasion or material failure during insertion or under shock and vibration, regardless of whether they are made of plastic or metal, due to design variations and material property differences.
Innovation Solution
A fastener assembly featuring a metal push pin with a bifurcated end and a separable stopper that locks the movable portions into engagement with the circuit board, providing enhanced resilience and durability through a throughbore mechanism, allowing for flexible engagement and secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plastic push pins with barbed ends are used for mounting heat sinks, then the pins can be easily inserted and engaged, but the barbed ends are prone to abrasion and breakage during insertion or use
Solution Approach 1:
The push pin is constructed from metal (such as brass) instead of plastic, providing a composite material solution that maintains the ease of insertion while significantly improving resistance to abrasion and breakage. The metal material combines ductility for engagement with strength for durability.
Solution Approach 2:
The invention changes the material parameters of the push pin from plastic to metal, altering physical properties such as yield strength, tensile strength, and hardness. This parameter change enables the pin to withstand shock and vibration while maintaining its engagement capability.
2Strength
If metal push pins with bifurcated ends are used to improve robustness, then strength is enhanced, but variations in design and material properties still lead to failures
Solution Approach 1:
The push pin is pre-formed with a bifurcated structure that is designed to flex during insertion. This preliminary configuration allows the barbs to naturally spread and engage the hole walls, compensating for variations in hole size and material properties without requiring precise manufacturing tolerances.
Solution Approach 2:
The bifurcated end is designed to be dynamic rather than static, allowing the metal portions to flex and adapt during insertion. This dynamic behavior enables the pin to accommodate variations in design parameters and material properties, ensuring reliable engagement across different applications.
3Ease of operation
If plastic push pins with stoppers and coil springs are used to provide clamping force, then engagement assistance is improved, but the plastic material remains subject to breakage under shock and vibration
Solution Approach 1:
The push pin is made from metal material that inherently provides both the structural strength to withstand shock and vibration and the elasticity to provide clamping force. This eliminates the need for separate plastic components while maintaining the beneficial clamping function.
Solution Approach 2:
The invention extracts and eliminates the separate coil spring and stopper components from the design. The metal push pin's own elastic properties replace the function of the coil spring, providing the necessary clamping force without requiring additional parts that could fail under shock and vibration.
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
The solution ensures robust and reliable attachment of heat sinks to printed circuit boards by preventing the movable portions from disengagement, even under stress conditions, while allowing for different stopper materials and designs to accommodate various push pin properties and board configurations.
Implementation Method 1
a bifurcated distal end having a pair of movable portions that are movable to flex toward and away from each other and arranged to engage at a hole of the component
Data Source
AI summary
Method and assembly for attaching a heat sink to a heat source surface associated with a printed circuit board or other component having a heat source. A fastener assembly may include a push pin with a barbed, bifurcated end arranged to be inserted through an opening of the printed circuit board and thereby secure the heat sink to the printed circuit board. A stopper may be headless, be separable from the push pin, and have a portion, such as a barrel-shaped element, positionable in a throughbore of the push pin that supports the bifurcated end so that movement of the barbed portions toward each other is resisted, thereby securing engagement of the barbed portions with the printed circuit board.