Eccentric Contact Spring for Reliable Probe Pin Testing
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Solution Overview
Problem
Conventional sockets for electrical parts face issues with probe pins where the plunger movement is not smooth, leading to varying contact pressures with IC package terminals, resulting in unreliable electrical tests and potential bad connections.
Innovation Solution
The design incorporates a contact spring with a closed coil portion and an open coil portion featuring eccentric rolls, which elastically supports the plunger, ensuring consistent contact and smooth vertical motion, thereby ensuring accurate electrical testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional contact spring is used, then the structure is simple, but the plunger cannot move smoothly and contact pressure varies widely
Solution Approach 1:
The contact spring incorporates an eccentrical portion with eccentrical rolls that are asymmetrically positioned relative to the spring axis. This asymmetry creates a mechanical advantage that ensures consistent contact between the plunger and contact spring, eliminating the variability in contact pressure while maintaining smooth plunger movement throughout the accommodation hole.
Solution Approach 2:
The invention modifies the geometric parameters of the contact spring by introducing an eccentrical portion with specific roll configurations. This parameter change transforms the spring's mechanical behavior, ensuring that the plunger maintains consistent contact pressure during its vertical motion without requiring complex additional components.
2Ease of manufacture
If conventional probe pins are used, then manufacturing is simple, but bad connections occur between terminals and probe pins
Solution Approach 1:
The contact spring's eccentrical portion creates asymmetric contact forces that ensure the plunger terminal maintains reliable electrical connection with the IC package terminal. This asymmetric design prevents bad connections while keeping the manufacturing process relatively simple, as it only requires modifying the spring geometry rather than redesigning the entire probe pin structure.
3Adaptability or versatility
If contact pressure varies widely, then individual probe pin design is flexible, but electrical test accuracy deteriorates
Solution Approach 1:
By changing the geometric parameters of the contact spring through the eccentrical portion design, the invention standardizes the contact pressure across all probe pins. This parameter modification ensures uniform electrical test accuracy while preserving the flexibility to design probe pins for different applications, as the fundamental spring mechanism remains adaptable.
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 reliable and accurate electrical testing by maintaining consistent contact pressures across all probe pins, preventing bad connections and ensuring smooth plunger operation.
Implementation Method 1
a contact spring that is in a shape of a coil and is contacted with the terminal of the external electric circuit, and a plunger that is biased by the contact spring
Implementation Method 2
the open coil portion comprises an eccentrical portion having at least one eccentrical roll, the eccentrical portion of the open coil portion and the closed coil portion are configured so as to elastically pinch the conductive portion of the plunger in a radical direction
Data Source
AI summary
A electric contact pin which can certainly contact a plunger with a contact spring and ensure smooth operation (vertical motion) of the plunger. The present invention can execute electrical tests of the electrical parts accurately. The electric contact pin according to the present invention contacts an eccentrical portion of an open coil portion provided for the contact spring capable of easily deforming in a radial direction with a conductive portion of the plunger. Consequently, the conductive portion of the plunger is elastically pinched between the eccentrical portion of the open coil portion and the closed coil portion. The eccentrical portion of the open coil portion and the closed coil portion are contact with the conductive portion of the plunger at any time.