Three-Contact Bridge Assembly for Low-Resistance Switching
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Solution Overview
Problem
Switching devices such as relays or contactors face challenges in maintaining low transition resistance and durability while handling high electrical currents, often leading to increased contact resistance, arcing, and wear due to misalignment and production tolerances.
Innovation Solution
A contact bridge sub-assembly with three switching contacts arranged to span a plane, featuring rounded or curved shapes, and supported by a spring assembly with independent deflectable elements, ensuring secure contact even with misalignment, and a compact design with interlaced contact bridges for reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional contact bridge designs are used with linear contact arrangements, then manufacturing is simpler, but contact reliability decreases due to misalignment and production tolerances
Solution Approach 1:
The contact bridge transitions from a linear one-dimensional contact arrangement to a two-dimensional planar configuration with three contacts spanning a plane. This dimensional change allows the contacts to form a stable triangular pattern that compensates for misalignment in multiple directions, significantly improving contact reliability while managing structural complexity
Solution Approach 2:
The contact bridge is divided into three separate contact points arranged in a triangular pattern rather than a single linear arrangement. This segmentation allows each contact to independently accommodate misalignment, and the combined triangular configuration provides overall stability and reliability
2Power
If contact bridges are designed for high current switching, then current handling capacity increases, but contact resistance and heat generation increase leading to wear
Solution Approach 1:
The switching contacts are given a rounded or dome-shaped local geometry at their contact surfaces. This localized curvature increases the contact area with the stationary contacts, distributing the high current density and reducing heat generation at any single point, thereby improving contact durability while maintaining high current handling capacity
Solution Approach 2:
The contacts are designed with curved or rounded surfaces rather than flat surfaces. This spherical geometry naturally increases the contact area when pressed against stationary contacts, reducing contact resistance and heat generation, which is critical for reliable high-current switching
3Reliability
If contact bridges are pressed against stationary contacts with high force, then contact resistance decreases, but wear and arcing increase
Solution Approach 1:
The three-contact planar configuration distributes the pressing force across multiple contact points rather than concentrating it at a single location. This dimensional distribution maintains low contact resistance through adequate force while reducing wear and arcing at each individual contact point, extending contact lifespan
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 electrical contact, reduces wear, and maintains low resistance, enhancing durability and efficiency in high-current applications.
Implementation Method 1
supported by a spring assembly with independent deflectable elements
Data Source
AI summary
A contact bridge sub-assembly for an electric switching device such as a relay or a contactor, comprising a contact bridge that is movable along a switching direction, wherein exactly three switching contacts are arranged on the contact bridge, the three switching contacts spanning a contact plane. A contact bridge assembly including such contact bridge sub-assemblies and an electric switching device including at least one contact bridge sub-assembly and/or assembly. The contact bridge sub-assembly reduces electrical losses, heat generation and wear of an electric switching device. At the same time, such electric switching devices are durable, built compactly and cost-effective to manufacture.