Adjustable Spiral Spring Drive Mechanism for Medium Voltage Switches

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Solution Overview

Problem

Current drive mechanisms for Medium Voltage switches face issues with increased frictional forces between contact blades, requiring over-dimensioning of springs, precise dimensioning and testing, and high manufacturing and maintenance costs, while also experiencing reduced speed characteristics over time due to spring degradation.

Innovation Solution

A drive mechanism featuring a spiral spring assembly with release means and adjusting means, allowing for manual rotation to apply additional forces and fine-tune pre-load, enabling operation under increased friction and reducing the need for precise spring dimensioning and testing, while maintaining compactness and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring is over-dimensioned to handle increased frictional forces, then the switch can operate under all conditions, but manufacturing costs increase

Engineering Contradiction:
Improveoperation reliability under increased frictionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces an adjustable mechanism that allows the spring pre-load to be modified after assembly. This dynamic adjustment capability enables the system to adapt to varying friction conditions without requiring an over-dimensioned spring for all possible scenarios, thereby reducing manufacturing costs while maintaining operational reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention allows changing the spring pre-load parameter through the adjustable mechanism. By enabling post-assembly adjustment of the pre-load parameter, the system can be optimized for specific operating conditions rather than being designed for worst-case scenarios, reducing the need for over-dimensioning and associated manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the spring is accurately dimensioned and tested for speed requirements, then the switch meets speed specifications, but manufacturing and testing costs increase

Engineering Contradiction:
Improveopening/closing speedVSAvoiddimensioning and testing cost
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The adjustable mechanism allows the spring pre-load to be fine-tuned after assembly to achieve the desired speed characteristics. This eliminates the need for expensive pre-testing and accurate dimensioning during manufacturing, as adjustments can be made post-assembly to meet speed specifications.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mechanism is designed to allow preliminary adjustments after assembly rather than requiring precise preliminary dimensioning during manufacturing. This reverses the traditional approach where accuracy must be achieved during manufacturing, shifting the adjustment phase to after assembly when the system can be optimized based on actual performance.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If a simple drive mechanism is used, then manufacturing costs are reduced, but the mechanism cannot handle increased frictional forces

Engineering Contradiction:
Improvemanufacturing costVSAvoidoperation capability under increased friction
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent adds an adjustable component to a relatively simple drive mechanism, enabling it to handle increased frictional forces. The adjustment capability allows the mechanism to be adapted to different friction conditions without requiring a completely complex design, maintaining cost-effectiveness while improving reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustable mechanism provides multi-functionality by enabling the same simple drive mechanism to operate reliably under both normal and increased friction conditions. The adjustment feature allows a single design to serve multiple operating scenarios, eliminating the need for different mechanisms for different conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If the spring characteristics are not adjusted, then the design is simpler, but the spring may degrade over time reducing switch speed

Engineering Contradiction:
Improvedesign complexityVSAvoidswitch speed over time
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The adjustable mechanism enables operators to service and re-adjust the spring pre-load after degradation occurs. This self-service capability allows the system to maintain its speed characteristics over time without requiring replacement of the entire spring or mechanism, balancing design simplicity with long-term performance.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The adjustment mechanism allows recovery of the spring's optimal performance characteristics after degradation by re-adjusting the pre-load. Instead of discarding the degraded spring, the system can recover its functionality through adjustment, extending the service life and maintaining speed characteristics.

Inventive Principle:
Principle #34Discarding and recovering

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 allows for efficient operation under increased frictional forces, reduces manufacturing and maintenance costs, and allows for easy calibration of spring characteristics, ensuring reliable and cost-effective performance over time.

Implementation Method 1

a spring assembly which comprises a spiral spring having a first end operatively coupled to said operating shaft and a second end operatively couplable to said power shaft, said spiral spring being loaded by rotation of said operating shaft and actuating said power shaft when released

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2249360B1Drive mechanism for medium voltage switch
Publication Date: 2012.07.04 ABB TECHNOLOGY AG
  • EP2249360B1 patent drawingFigure 1
  • EP2249360B1 patent drawingFigure 2
  • EP2249360B1 patent drawingFigure 3

AI summary

A drive mechanism for a Medium Voltage switch which comprises: a base plate 10 and a front plate 11 defining an internal space housing an operating shaft 2 and a power shaft 3, coaxially mounted on a first longitudinal axis, the power shaft 3 being operatively connectable to a kinematic chain of a Medium Voltage switch for opening/closing operation of said switch, the operating shaft 2 having a head 20 connectable to an operating handle for manual actuation of said shaft; a spring assembly 4 which comprises a spiral spring 41 having a first end 411 operatively coupled to said operating shaft 2 and a second end 412 operatively couplable to said power shaft 3, said spiral spring 41 being loaded by rotation of said operating shaft and actuating said power shaft when released. The operating shaft 2 is provided with release means 21 acting on said power shaft 3 by manual rotation of said operating shaft 2 and the spring assembly 4 is provided with adjusting means 40 for regulating the pre-load of said spiral spring 41.