Nested Flat Plate Coil Spring for Pogo Pin Motion
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Solution Overview
Problem
Conventional miniaturized pogo pins with short lengths face challenges in providing a sufficient range of motion and spring force while maintaining low electrical resistance, due to the limitations of coil spring design and manufacturing complexity.
Innovation Solution
A miniaturized coil spring is formed by bending a metal strip into a periodically repeated pattern of U- or S-shapes with inward and outward bending points, allowing for a high width-to-height ratio, which enhances the range of motion and spring force, and is manufactured using progressive stamping to reduce costs and improve mechanical and electrical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the length of the pogo pin is reduced to minimize size, then the outer diameter and length are decreased, but the range of motion of the probe is insufficient
Solution Approach 1:
The coil spring is formed by nesting multiple loops of metal strip within a compact space. Each loop is positioned inside the previous one, creating a nested structure that maximizes the spring's compression distance within a limited axial length, thereby providing sufficient range of motion in a miniaturized pogo pin.
Solution Approach 2:
The metal strip is configured with a high width-to-height ratio, utilizing the width dimension more effectively. By making the strip wider and shorter in height, the spring can achieve greater lateral flexibility and range of motion without increasing the axial length of the pogo pin.
2Length of moving object
If the diameter of the coil spring is reduced to minimize size, then the outer diameter is decreased, but the spring force is decreased
Solution Approach 1:
The spring is constructed from a metal strip with optimized material properties and cross-sectional geometry. By controlling the width and height of the strip and configuring it into a nested loop pattern, the design achieves high spring force density within a small diameter, compensating for the reduced size through structural optimization rather than material substitution.
Solution Approach 2:
The nested loop configuration creates curved stress distribution paths that efficiently utilize the material's elastic properties. The multiple concentric arcs in the nested structure provide progressive engagement during compression, maintaining high spring force despite the small overall diameter.
3Length of moving object
If the number of turns of the coil spring is reduced to minimize length, then the length is decreased, but the range of motion is insufficient
Solution Approach 1:
The nested loop structure allows multiple effective turns to be contained within a short axial distance. Each nested loop contributes to the overall range of motion through progressive compression, achieving sufficient total travel distance without requiring many sequential turns that would increase the spring's length.
Solution Approach 2:
The spring design incorporates variable loop spacing and sizing within the nested structure, with larger outer loops providing initial compression travel and smaller inner loops providing additional travel and force regulation. This dynamic configuration maximizes range of motion within the available length.
4Device complexity
If a conventional coil spring design is used, then the structure is simple, but the manufacturing complexity increases due to assembly requirements
Solution Approach 1:
The coil spring is formed as a single integrated piece from one continuous metal strip through progressive stamping. The nested loop pattern is created in a single forming process without requiring separate components or assembly steps, combining the simplicity of a single-piece construction with the functional complexity of a multi-loop spring structure.
Solution Approach 2:
The progressive stamping process automatically forms the nested loop configuration and creates the necessary geometric features directly from the metal strip. The manufacturing process self-generates the complex geometry without requiring additional machining, heat treatment, or assembly operations, reducing overall manufacturing complexity.
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 enables a pogo pin with a sufficient range of motion and strong spring force while minimizing electrical resistance, reducing manufacturing costs and improving mechanical and electrical reliability, making it suitable for applications in semiconductor inspection and other electronic devices.
Implementation Method 1
the metal strip includes one or more inward bending points and one or more outward bending points, the inward bending points and the outward bending points being bent in opposite directions
Data Source
AI summary
A coil spring, a pogo pin having the coil spring, and manufacturing methods thereof are provided. The method for manufacturing a coil spring includes i) preparing a metal strip 200 with a periodically repeated U- or S-shape pattern, and ii) bending the metal strip 200 at one or more inward bending points 210 and at one or more outward bending point 220, which are formed on the metal strip 200, in opposite directions, the inward bending point and the outward bending point being spaced apart from each other. The coil spring and the pogo pin may be manufactured to be small in size and low in manufacturing costs as compared with conventional ones. Further, the coil spring and the pogo pin may provide a sufficient maximum range of motion and spring force of a probe.