Spring Contact Assembly with Overlapping Flat Plungers
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Solution Overview
Problem
Conventional spring-loaded contact probes are expensive to manufacture due to costly machining operations and have a short lifespan, leading to frequent replacements, which is a challenge in high-frequency testing where impedance matching is crucial.
Innovation Solution
A spring contact assembly with two movable and overlapping plungers having flat contact surfaces surrounded by an external spring, utilizing natural torsional movement to maintain contact and enhance electrical conductivity, with reduced diameter coil sections and offset coil sections to constrain plunger tails and improve interaction, allowing for cost-effective manufacturing through stamping or lathe processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spring-loaded contact probes are manufactured using traditional machining operations, then manufacturing precision and reliability are improved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent changes the manufacturing parameters by transitioning from traditional machining operations to stamping or lathe processes. This parameter change allows for cost-effective manufacturing while maintaining the functional requirements of the contact assembly through optimized flat plunger geometries
Solution Approach 2:
The patent employs flat plunger geometries that can be manufactured through stamping or lathe processes, which are more cost-effective than traditional machining. These simplified designs enable high-volume production at lower costs while maintaining adequate performance for the application
2Force
If conventional spring-loaded contact probes are used, then contact force is maintained, but lifespan is short requiring frequent replacements
Solution Approach 1:
The patent utilizes the natural torsional movement of the spring to maintain contact throughout the compression stroke. This dynamic approach allows the contact surfaces to adapt to movement and maintain reliable electrical contact while extending the lifespan of the assembly
Solution Approach 2:
The flat surfaces on the plunger tail portions are pre-configured to pass over and make contact with opposing plunger tail portions inside the spring. This preliminary arrangement ensures that contact is maintained throughout the compression stroke, preventing false opens and extending operational lifespan
3Reliability
If external spring probes with shorter length are used to avoid signal attenuation, then high-frequency signal transmission is improved, but manufacturing cost increases due to costly machining operations
Solution Approach 1:
The patent changes the manufacturing approach from costly machining operations to stamping or lathe processes for producing flat plunger geometries. This parameter change enables cost-effective manufacturing of short-length external spring probes that maintain high-frequency signal transmission quality
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 design improves the lifespan and performance of spring contact assemblies by maintaining contact throughout the compression stroke, enhancing electrical conductivity, and reducing manufacturing costs through the use of flat plunger geometries suitable for stamping or lathe production, facilitating high-volume assembly and plating.
Implementation Method 1
Utilizing the natural torsional movement of the spring while it is compressed, the flat surfaces of the plunger tail portions maintain contact throughout the compression stroke of the contact assembly
Implementation Method 2
The spring has end coils that press onto each of the opposing plungers to prevent the plungers from separating from the spring, thus fixing the plunger contact portion and the tail portions with respect to each end of the spring
Implementation Method 3
The contact between the opposing flat sections prevents the twisting or torsional movement of the spring from translating to the tips on the contact portions
Data Source
AI summary
A spring contact assembly having a first plunger with a tail portion having a flat contact surface and a second plunger having a tail portion with a flat contact surface wherein the flat contact surfaces are overlapping and are surrounded by an external compression spring such that the sliding engagement of the flat surfaces increases during compression of the spring.