Reworkable Spring Screw Fastener for Even Bare Die Clamping
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Solution Overview
Problem
Conventional methods for connecting heat dissipation devices to bare die heat sources result in uneven force distribution, leading to potential damage and thermal resistance due to asynchronous tightening of screws and springs, which are not reusable.
Innovation Solution
A reworkable fixing element comprising a screw, sleeve, and spring retaining ring, allowing synchronous application of even downward forces through a spring mechanism that can be reused by compressing the spring again using a reworking tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If screws are sequentially tightened to screw fastening points one by one, then the heat dissipation device can be connected to the base, but the downward forces are unevenly distributed causing the bare die to be easily broken and damaged
Solution Approach 1:
The fixing element is segmented into multiple independent components: a screw portion for thread engagement, a spring portion for elastic force application, and a pressing portion for contact with the heat dissipation device. This segmentation allows each component to perform its specific function - the screw provides mechanical fastening while the spring provides uniform elastic pressing force, resolving the contradiction between ease of assembly and reliability of force distribution
Solution Approach 2:
The spring portion changes the force application parameter from rigid (screw only) to elastic (spring-loaded), enabling the fixing element to apply uniform downward forces even when tightened at different times. The spring's elastic property compensates for timing differences in tightening operations, maintaining bare die integrity while preserving manufacturing efficiency
2Productivity
If each screw unit is fully tightened in one movement at very quick speed, then the fixing time on production line is shortened, but the springs are quickly compressed resulting in uneven and asynchronous distribution of downward forces
Solution Approach 1:
The spring portion acts as a cushioning element that absorbs and equalizes the impact of quick tightening operations. By positioning the spring between the screw head and the pressing portion, it provides beforehand cushioning that prevents sudden force spikes and ensures uniform force distribution even when screws are tightened quickly and asynchronously, thus maintaining manufacturing precision while preserving high productivity
3Adaptability or versatility
If the heat dissipation device is connected to a base with internally threaded copper sleeve rods, then the bare die can be mounted, but the screws are not tightened synchronously causing the heat dissipation device to be skewed relative to the heat source
Solution Approach 1:
The spring portion provides self-service by automatically adjusting and equalizing forces during the tightening process. As each screw is tightened, the spring compresses and stores elastic energy, then releases it to apply uniform downward pressure on the heat dissipation device. This self-regulating mechanism compensates for asynchronous tightening and maintains alignment stability without requiring external synchronization control
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
Ensures even contact and prevents damage to the bare die by synchronously applying forces, while being reusable, thus maintaining effective heat transfer and reducing thermal resistance.
Implementation Method 1
a spring having a top and a bottom end, wherein the bottom end of the spring is pressed against the retaining ring
Implementation Method 2
the released spring can not be compressed again in the screw sleeve. The old spring loaded screw with the released spring must be dismounted from the heat dissipation device and be replaces with a new one
Data Source
AI summary
A reworkable fixing element includes a screw having a spring fitted thereon, a screw head with two opposite cuts, and a retaining ring for stopping the screw from axially moving down any further; a sleeve disposed outside the screw and the spring, and including two opposite windows near an upper end thereof and a coupling zone located below the windows; a spring retaining ring fitted around the coupling zone and including two upward hooked arms extended through the windows to press the spring to a compressed state. The used fixing element has an elastically released spring but is reworkable using a reworking tool, which pushes the spring into the sleeve via the two cuts. Then, the hooked arms are allowed to extend through the windows to press on and hold the spring in the compressed state again, and the fixing element is ready for use a second time.