Contact Spring Assembly for Low-Voltage Circuit Breakers
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Solution Overview
Problem
Existing contact spring assemblies in low-voltage circuit breakers are complex, consume valuable space, difficult to assemble, and provide inadequate individualized contact pressure, affecting the circuit interruption performance due to their large size and mass.
Innovation Solution
A contact spring assembly design featuring a first and second housing member, a spring guide with holes, sliders, and springs that individually bias movable contact arms, providing consistent pressure and allowing independent movement while being compact and cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional contact spring assembly with multiple springs and a separate unit design is used, then contact pressure can be provided to the movable contact assembly, but the assembly becomes complex, consumes valuable space, and is difficult to assemble
Solution Approach 1:
The patent integrates the contact spring assembly with the contact arm carrier into a single unified structure. The spring assembly is no longer a separate unit but is combined with the carrier, eliminating the need for separate assembly and reducing overall complexity while maintaining the contact pressure function.
Solution Approach 2:
The contact arm carrier is designed to serve multiple functions: it acts as both the carrier for the movable contact arms and as the housing for the contact spring assembly. This multi-functional design reduces the number of separate components needed while maintaining all necessary functions.
2Force
If a traditional contact spring assembly with a separate unit disposed beside the contact arm carrier is used, then contact pressure can be maintained, but valuable space within the circuit breaker housing is consumed
Solution Approach 1:
The contact spring assembly is nested within the contact arm carrier structure. The springs are positioned inside the carrier housing, allowing the spring assembly to occupy the same spatial envelope as the carrier itself, thereby eliminating additional space requirements.
Solution Approach 2:
By merging the contact spring assembly with the contact arm carrier, the patent eliminates the need for a separate discrete unit disposed beside the carrier. The combined structure occupies only the space necessary for the carrier itself, maximizing the use of available space within the circuit breaker housing.
3Force
If a traditional contact spring assembly with large size and inconvenient location is used, then contact pressure can be provided, but the dimension available to accommodate the motion of the movable contact assembly is reduced
Solution Approach 1:
The spring assembly is nested within the carrier structure, positioned in a location that does not interfere with the motion path of the movable contact arms. This nesting approach allows the springs to provide contact pressure while occupying space that would otherwise be available for contact arm movement.
Solution Approach 2:
The contact spring assembly is positioned at a specific location on the carrier that optimizes both contact pressure application and motion accommodation. The springs are located to apply force locally at the contact points while leaving the central and peripheral areas clear for the contact arms to move freely during opening and closing operations.
4Force
If a traditional contact spring assembly with large mass is used, then contact pressure can be maintained, but the opening velocity of the movable contact assembly is decreased
Solution Approach 1:
By combining the contact spring assembly with the contact arm carrier, the patent reduces the total mass of the moving components. The integrated design eliminates redundant structural elements and reduces the overall weight that must be accelerated during opening operations, thereby improving opening velocity.
Solution Approach 2:
The patent changes the mass parameter of the contact spring assembly by using a more compact, integrated design with fewer materials. This reduction in mass directly improves the opening velocity of the movable contact assembly while maintaining the necessary contact pressure through optimized spring positioning and force distribution.
5Force
If a contact spring assembly that biases a common element engaging all fingers simultaneously is used, then contact pressure can be provided, but accurate and consistent individual contact pressure to each contact arm cannot be achieved
Solution Approach 1:
The contact spring assembly is segmented into multiple independent spring units, with each spring individually biasing a specific movable contact arm. This segmentation allows each contact arm to receive precisely controlled contact pressure independent of the others, enabling accurate and consistent individual contact pressure while maintaining overall system functionality.
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 new design provides accurate and consistent contact pressure to individual movable contact arms, reduces assembly complexity, and enhances the circuit breaker's performance by optimizing the mechanical advantage and reducing mass, thus improving the opening velocity and thermal performance.
Implementation Method 1
a plurality of springs, each of the springs having a first end received by a corresponding one of the spring holes of the spring guide, and a second end coupled to a corresponding one of the sliders. Each of the springs and the corresponding one of the sliders coupled thereto is structured to individually bias a corresponding one of the movable contact arms
Data Source
AI summary
A contact spring assembly is provided for an electrical switching apparatus including a movable contact assembly and a stationary contact assembly having stationary electrical contacts. The movable contact assembly includes a carrier assembly, and movable contact arms pivotably coupled to the carrier assembly and carrying movable electrical contacts. The contact spring assembly includes a first contact spring housing member, a second contact spring housing member coupled to and disposed opposite from the first contact spring housing member, a spring guide disposed between and coupled to at least one of the first and second contact spring housing members and including spring holes, springs received in the spring holes, and sliders coupled to the springs. The springs and sliders individually bias the movable contact arms and movable electrical contacts toward engagement with corresponding stationary electrical contacts. A movable contact assembly and an electrical switching apparatus are also disclosed.