Three-Position Disconnector Switch With Anti-Rotation Piston Locking

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Solution Overview

Problem

Existing three-position disconnector switches face challenges in eliminating unwanted rotation of the piston during linear movement, which complicates determining the switch position and can lead to increased size and temperature rise issues.

Innovation Solution

Incorporating flexible locking elements that move into and out of a groove on the piston as it transitions between switch positions, ensuring constant constraint against axial rotation without compromising the disconnector's length or dielectric performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a linear three-position disconnector is propelled by screw, then the piston can be moved between switch positions, but the piston is subjected to torque and unwanted rotation occurs

Engineering Contradiction:
Improvepiston movement between switch positionsVSAvoidpiston rotational stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

A groove is introduced as an intermediary feature on the piston surface, which interacts with a locking element to prevent rotation. The groove serves as a mediator between the piston and the locking mechanism, enabling rotational constraint without interfering with the linear movement function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The piston surface is segmented by introducing a groove that divides the surface into distinct regions. This segmentation allows the locking element to engage with a specific portion of the piston through the groove, providing rotational constraint while maintaining overall piston integrity and movement capability.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the piston length is increased to prevent rotation, then rotational stability is improved, but the overall device size increases and dielectric performance deteriorates

Engineering Contradiction:
Improvepiston rotational stabilityVSAvoidpiston length
Core Design Contradiction:
Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The groove acts as an intermediary structural feature that provides rotational stability without requiring increased piston length. By introducing this intermediate element, the patent achieves rotational constraint while maintaining compact dimensions and acceptable dielectric performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of uniformly increasing the entire piston length, the groove is introduced as a localized feature at a specific position on the piston surface. This local modification provides rotational constraint precisely where needed, without unnecessarily increasing overall piston length or compromising dielectric properties.

Inventive Principle:
Principle #3Local quality

3Strength

If the piston length is increased to improve dielectric performance, then dielectric strength is improved, but the device becomes larger and more complex

Engineering Contradiction:
Improvedielectric strengthVSAvoidpiston length
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The groove is positioned at a specific location on the piston surface where it provides rotational constraint without unnecessarily extending the piston length in directions that would compromise dielectric performance. This localized approach allows maintaining adequate dielectric strength while avoiding excessive size increase.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove serves as an intermediary feature that addresses rotational stability needs without requiring proportional increases in piston length that would adversely affect dielectric performance. This intermediate structure enables decoupling of rotational constraint requirements from overall size scaling.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution effectively prevents piston rotation while minimizing the overall length and maintaining dielectric performance, providing a space-efficient and reliable three-position disconnector switch.

Implementation Method 1

Rotation of the threaded rod is configured to engage with the inner threaded section to move the piston along an axis of the switch between the different switch positions

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

Each of the flexible locking elements is configured such that a part of each of the flexible locking elements moves into and out of the groove as the piston is moved along the axis of the switch between the different switch positions

Methodology Applied
Scientific EffectFlexible constraint mechanism: Elasticity

Data Source

PatentEP4089699B1Three-position disconnector switch
Publication Date: 2023.11.29 ABB (SCHWEIZ) AG
  • EP4089699B1 patent drawingFigure 1
  • EP4089699B1 patent drawingFigure 2

AI summary

The present invention relates to a three-position disconnector switch, comprising: a power in contact (1); a piston (2); a power out contact (4); a plurality of flexible locking elements (5); an earthing contact (6); and a threaded rod (7). A length of the piston is such that in a first switch position an outer surface of a wall of the piston makes an electrical contact between the power in contact and the power out contact. The length of the piston is such that in a second switch position the outer surface of the wall of the piston does not make an electrical contact with either the earthing contact or the power in contact, and wherein in the second switch position the outer surface of the wall of the piston makes an electrical contact with the power out contact. The length of the piston is such that in a third switch position the outer surface of wall of the piston makes an electrical contact between the earthing contact and the power out contact. The piston comprises an inner threaded section configured to engage with the threaded rod, and wherein rotation of the threaded rod is configured to engage with the inner threaded section to move the piston along an axis of the switch between the different switch positions. The piston comprises a groove extending in a direction parallel to the axis. Each of the flexible locking elements is configured such that a part of each of the flexible locking elements moves into and out of the groove as the piston is moved along the axis of the switch between the different switch positions as the piston is moved in both directions along the axis. As the piston is moved along the axis the switch is configured such that there is always a part of at least one flexible locking element in the groove. When a part of at least one flexible locking element is in the groove the piston is constrained from rotating about the axis.