Snap-Action Switch Box Using a Single Torsion Spring
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Solution Overview
Problem
Existing snap-action switch boxes for disconnectors require additional electrical insulations due to metal components, complicating manufacture and assembly, and necessitate specific orientation of torsion springs and special types of springs for bidirectional actuation.
Innovation Solution
A snap-action switch box with a reduced number of metallic elements, using polymeric materials for the rotating elements and base, allowing for simplified assembly without considering torsion spring orientation, and utilizing a single commercially available torsion spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal components are used inside the snap-action switch box, then the mechanical strength and durability are improved, but additional electrical insulations are required which complicates manufacture and assembly
Solution Approach 1:
The patent removes metal components from the snap-action switch box internal structure, extracting the problematic element that required additional insulation. The housing and internal components are made from electrically insulating materials, eliminating the need for separate insulation layers while maintaining mechanical integrity through material selection and structural design.
Solution Approach 2:
The patent employs composite or specially formulated insulating materials for the housing and internal components that provide both mechanical strength and electrical insulation properties simultaneously. This eliminates the need for separate metal and insulation layers, simplifying the structure while maintaining both strength and insulation requirements.
2Reliability
If torsion springs are mounted in a specific orientation, then the switching mechanism functions correctly, but the assembly process is slowed down
Solution Approach 1:
The patent employs an asymmetric indexing element with raised portions positioned at specific angular intervals that work with the torsion spring mechanism. This asymmetric design ensures correct functional operation while the raised portions and indexing features guide the assembly process, making the correct orientation more apparent and reducing assembly time.
Solution Approach 2:
The indexing element is pre-configured with raised portions and the torsion spring is pre-loaded or pre-positioned in a specific orientation before final assembly. This preliminary preparation ensures that when components are assembled, they are already in the correct functional configuration, eliminating the need for post-assembly orientation adjustments.
3Adaptability or versatility
If bidirectional actuation is enabled, then the versatility of the switch box is improved, but special types of torsion springs or multiple springs are required
Solution Approach 1:
The patent designs a universal indexing element and torsion spring configuration that can accommodate bidirectional actuation using a single standard torsion spring. The indexing element features raised portions positioned to engage with the actuation mechanism regardless of rotation direction, allowing one spring to provide the necessary snap-action in both clockwise and counter-clockwise directions.
Solution Approach 2:
The patent employs an indexing element design where the raised portions are positioned to work with the torsion spring in a configuration that enables bidirectional operation. By inverting or repositioning the indexing features compared to traditional unidirectional designs, the system achieves versatility with a single spring rather than requiring special spring types or multiple springs.
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 reduces manufacturing complexity, simplifies assembly, eliminates the need for special torsion springs, and ensures high reliability, ease of provision, and competitive costs for snap-action switch boxes, particularly for DC disconnectors in photovoltaic applications.
Implementation Method 1
a single torsion spring (12) of a type commonly commercially available or easy to provide, mounted on the indexing element (17) so as to be loadable by a rotation of the loading spindle (16) with respect to the indexing element (17) about the central axis (40a)
Data Source
AI summary
A snap-action switch box includes a base, a loading spindle, an indexing element associated rotatably with both, and a helical torsion spring which is mounted on the indexing element so that it can be loaded by a rotation of the loading spindle about a central axis. The spring has two stems which protrude from respective end turns of the spring and the indexing element includes at least two abutments which protrude in an eccentric position and in opposite directions and are substantially parallel to the central rotation axis. The stems of the spring are adapted to abut respectively against the abutments.