Three-Position Locking Device for Switchgear Drive Units

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Solution Overview

Problem

Existing locking devices for three-position drives in switchgear lack simplicity and cost-effectiveness while ensuring safety and reliability, particularly in high-voltage applications.

Innovation Solution

A locking device with a spindle drive and gear mechanism, utilizing two meshing gears with defined transmission ratios and locking disks, driven by a single motor or manually, which locks the switching device into predefined positions through engagement parts, ensuring accurate position indication and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking device for three-position drive is designed with high reliability and safety requirements, then the switching operations become reliable and positions are accurately displayed, but the design complexity and cost increase

Engineering Contradiction:
Improvereliability of switching operationsVSAvoiddesign complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is segmented into three independent locking elements (first, second, and third locking elements), each responsible for locking at a specific switching position. Each locking element has its own engagement parts that interact with corresponding engagement points on the drive shaft. This segmentation allows each element to be simple and reliable without requiring the entire system to be complex, as each segment independently ensures locking reliability at its designated position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking device uses a universal gear mechanism with a defined transmission ratio that drives all three locking elements simultaneously. The gear mechanism serves multiple functions: it transmits motion from the drive shaft, provides the defined number of revolutions for positioning, and coordinates the operation of all three locking elements. This multi-functionality reduces overall system complexity while maintaining reliability across all switching positions.

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

2Reliability

If a locking device uses multiple locking elements and engagement parts to ensure safety, then faulty switching is prevented, but the manufacturing cost and assembly complexity increase

Engineering Contradiction:
Improveprevention of faulty switchingVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking device merges three locking elements into a single integrated structure that is driven by one common gear mechanism. Instead of having three separate, independently actuated locking devices, the invention combines them so that a single drive shaft rotation simultaneously actuates all three locking elements through the gear mechanism. This merging reduces manufacturing cost by eliminating redundant drive mechanisms while maintaining the safety function of multiple locking points.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking elements are designed to automatically engage and lock at their respective positions based on the rotation of the drive shaft. The engagement parts of each locking element automatically interact with the corresponding engagement points on the drive shaft without requiring additional actuators or complex control systems. This self-service mechanism reduces manufacturing complexity and cost while ensuring that faulty switching is prevented through automatic positional locking.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the locking device requires a defined number of revolutions for accurate position indication, then the switching position is precisely displayed, but the mechanism becomes more complex and expensive

Engineering Contradiction:
Improveaccuracy of position indicationVSAvoidmechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The locking device uses a dynamic gear mechanism with a defined transmission ratio that automatically translates the rotational motion of the drive shaft into the precise positioning of all three locking elements. As the drive shaft rotates, the gear mechanism dynamically adjusts the rotation of each locking element to achieve the exact defined number of revolutions required for accurate position indication. This dynamic mechanism provides precise measurement without requiring separate sensors or complex electronic control systems for each position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gear mechanism serves as an intermediary between the drive shaft rotation and the locking elements. It mediates the transmission of motion, ensuring that the defined number of revolutions of the drive shaft results in the precise positioning of the locking elements. This intermediary mechanism simplifies the overall system by providing a mechanical means of achieving precise position indication without requiring complex electronic sensors, encoders, or control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If standard components are used to reduce cost, then manufacturing becomes more economical, but the precision and reliability may be compromised

Engineering Contradiction:
Improvemanufacturing economyVSAvoidswitching reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The locking device applies local quality by designing each locking element and its engagement parts with specific geometric features (such as undercut profiles) that are optimized for their local function of reliable locking. These locally optimized features ensure that each locking element reliably engages with its corresponding engagement point on the drive shaft. By focusing quality and precision on the critical local interfaces rather than requiring high precision throughout the entire mechanism, the invention achieves reliable switching using standard, cost-effective components.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2737509B1Locking device for a drive unit of a three-position drive mechanism for a connection device of switching assembly
Publication Date: 2016.08.31 ABB (SCHWEIZ) AG
  • EP2737509B1 patent drawingFigure 1
  • EP2737509B1 patent drawingFigure 2
  • EP2737509B1 patent drawingFigure 3

AI summary

The invention relates to a locking device for a drive unit for actuating a connection device of a switching assembly, said locking device comprising a spindle drive for actuating the connection device and a gear mechanism which is coupled therein, and can be driven by a drive motor or a manually controlled device and after a defined number of partial rotations of a drive shaft, connected to the gear mechanism, of the spindle arrangement, the connection device locks such that said connection device is brought into one of three predetermined locking positions and said position is displayed by means of at least one provided position display module. The gear mechanism comprises two mutually engaged toothed wheels (130, 140) having a defined transmission ratio, each toothed wheel (130, 140) interacting respectively with three thus connected locking disks (131, 132, 133, 134, 135, 136) and each locking position can be transmitted to a shift rod (10.1, 10.2, 10.3) arranged therein by respectively one of the three locking elements (210, 220, 230) which engage with pairs of locking disks (131, 132; 133, 134; 135, 136) associated with the locking elements (210, 220, 230), in order to display the shift position on the position display module.