Latch Assembly for Heat Sink Mounting on PCB
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Solution Overview
Problem
Existing heat sink mounting methods, such as spring clips and captive fasteners, are inadequate for securing heat sinks onto IC chips, especially at higher loads and in environments prone to vibration, and do not allow for convenient or precise control of the clamping force.
Innovation Solution
A latch assembly comprising a clamp with a spring, a rotatable handle, a cam, and a hook that engages the printed circuit board, allowing for controlled translation of the heat sink against the spring's bias to ensure secure contact with the IC chip, thereby facilitating efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional fasteners (screws or nuts) are used to secure heat sinks, then the heat sink can be mounted to the circuit board, but it becomes inconvenient and difficult to apply at higher fastening loads
Solution Approach 1:
The patent replaces traditional threaded fasteners (screws/nuts) with a cam-based mechanical system. The cam profile converts rotational motion of the handle into linear clamping force, eliminating the need for threading operations and making high-load fastening convenient through simple rotational motion.
Solution Approach 2:
The patent introduces a spring-loaded cam mechanism where the spring provides continuous pressure and the cam converts rotational input into controlled linear displacement. This dynamic system allows easy adjustment of clamping force through handle rotation while maintaining consistent pressure on the heat sink.
2Ease of operation
If spring clips are used to secure heat sinks, then the mounting process is simple, but the assembly becomes sensitive to vibration
Solution Approach 1:
The patent uses a cam profile (curved surface) to convert rotational motion into linear clamping force. The curved cam surface provides mechanical advantage and ensures consistent contact pressure, creating a more reliable vibration-resistant connection compared to simple spring clips while maintaining ease of operation.
3Reliability
If captive fasteners are used to engage heat sink flanged corners, then the heat sink can be securely mounted, but precise control of clamping force is not achieved
Solution Approach 1:
The patent employs a spring-loaded cam mechanism where the spring constant and cam profile geometry can be designed to provide precise control over clamping force. By adjusting spring parameters or cam profile shape, the exact amount of force applied to the heat sink can be controlled, ensuring both secure mounting and precise force regulation.
4Force
If higher fastening loads are applied to secure the heat sink, then better heat contact is achieved, but the risk of damage to components increases
Solution Approach 1:
The patent incorporates a spring element that acts as a cushion between the cam mechanism and the heat sink. The spring absorbs excess force and provides compliant contact, ensuring high clamping force is applied smoothly without sudden impacts that could damage the heat sink or IC chip, while still achieving good thermal contact.
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 latch assembly provides a reliable and efficient means of securing heat sinks onto IC chips, allowing for precise control of clamping force and ensuring consistent heat transfer, even at higher loads, while minimizing the risk of damage to components and maintaining airflow.
Implementation Method 1
a spring mounted to the clamp for biasing the clamp away from the heat sink
Implementation Method 2
a cam extending from the handle; a hook moveably mounted to the clamp and having a cam surface engaged with the cam, wherein rotation of the handle causes movement of the cam along the cam surface, which causes translation of the clamp toward the printed circuit board
Implementation Method 3
a heat sink for dissipating heat from the integrated circuit device; the heat sink to contact the integrated circuit device for dissipating heat from the integrated circuit device
Data Source
AI summary
A latch assembly for latching a heat sink onto a printed circuit board (PCB). The latch assembly includes a clamp having a connector for connecting the latch assembly to the heat sink. A spring is mounted to the clamp for biasing the clamp away from the heat sink. A handle is rotatably connected to the clamp, and a cam extends from the handle. A hook is moveably mounted to the clamp and has a cam surface engaged with the cam. The hook has an engagement portion for engaging the PCB. Rotation of the handle causes (i) rotation of the hook, which causes the engagement portion to engage the PCB, followed by (ii) movement of the cam along the cam surface, which causes translation of the clamp toward the PCB against the bias of the spring, which causes the heat sink to contact an IC for dissipating heat from the IC.