Earthing Switch Operating Unit With Mechanical Status Indication

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Solution Overview

Problem

Existing earthing switch drive operating units for air-insulated switchgear are often bulky and expensive, and lack reliable status indication for maintenance personnel, posing safety risks due to reliance on auxiliary voltage for status displays.

Innovation Solution

A compact operating unit with a rotatable shaft, radial pins, and stops that define end positions, integrated with a mechanical status indicator, allowing manual operation and reliable status indication without auxiliary power, utilizing sheet metal components for cost-effectiveness and space efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional operating unit with separate components for shaft positioning and status indication is used, then the status indication can be provided, but the device becomes bulky and expensive

Engineering Contradiction:
Improvestatus indication reliabilityVSAvoidoperating unit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the shaft positioning mechanism (pin and stops) with the status indication mechanism into a single integrated operating unit. The pin that defines the shaft's end positions also directly actuates the status indicator, eliminating the need for separate components and reducing overall device complexity while maintaining reliable status indication.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pin serves multiple functions: it defines the shaft's rotational end positions, limits the shaft's rotation range, and simultaneously actuates the status indicator to display the shaft position. This multi-functionality reduces the number of components needed and simplifies the operating unit's structure.

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

2Reliability

If an auxiliary power supply is used for status indication, then the status can be displayed, but the system becomes dependent on auxiliary voltage which may fail

Engineering Contradiction:
Improvestatus indication reliabilityVSAvoidauxiliary power dependency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The status indicator is actuated directly by the mechanical movement of the pin and shaft, without requiring any external power supply. The system uses its own operational movement (shaft rotation) to automatically update the status indication, making it independent of auxiliary voltage and ensuring reliable operation even when power is unavailable.

Inventive Principle:
Principle #25Self-service

3Volume of moving object

If a compact operating unit design is used, then space is saved, but the manufacturing cost and complexity may increase

Engineering Contradiction:
Improveoperating unit volumeVSAvoidmanufacturing simplicity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The operating unit is divided into simple, modular components: a shaft with radially extending pins, separate stops for positioning, and a status indicator mechanism. This segmentation allows each component to be manufactured independently using simple processes, then assembled together, maintaining ease of manufacture while achieving a compact overall design.

Inventive Principle:
Principle #1Segmentation

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 enables safe and cost-effective manual operation of earthing switches with reliable status indication, independent of auxiliary power, enhancing occupational safety and reducing the operational complexity and cost of air-insulated switchgear.

Implementation Method 1

The first stop (8) and the second stop (9) are arranged relative to the shaft (3.1, 3.2) in such a way that the shaft (3.1, 3.2) moves between a first shaft position, in which the at least one pin (6) strikes the first stop (8), and a second shaft position, in which the at least one pin (6) strikes the second stop (9)

Methodology Applied
Scientific EffectMechanical contact and constraint: Mechanical Force

Implementation Method 2

the shaft also has at least one pin which extends radially away from the shaft. In addition, the operating unit has a first stop and a second stop for the at least one pin... an eccentric for transmitting a rotary movement of the shaft to the earthing switch drive

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Implementation Method 3

at least one shaft which is rotatably mounted in a bearing

Methodology Applied
Scientific EffectFriction reduction through bearing: Ball Bearing

Data Source

PatentEP3872941B1Operating unit for an earthing switch of an air-insulated switchgear
Publication Date: 2023.09.06 SIEMENS AG
  • EP3872941B1 patent drawingFigure 1
  • EP3872941B1 patent drawingFigure 2
  • EP3872941B1 patent drawingFigure 3

AI summary

The invention relates to an operating unit (1) for an earthing switch actuator (17) of an air-insulated switchgear and an air-insulated switchgear assembly with such an operating unit (1). The operating unit (1) has at least one shaft (3.1, 3.2) rotatably mounted in a bearing (2), which has at a first end a socket (4) for a hand-operated crank and at a second end an eccentric (5) for transmitting a rotary movement of the shaft (3.1, 3.2) to the earthing switch actuator (17). According to the invention, the shaft (3.1, 3.2) also has at least one pin (6) extending radially away from the shaft (3.1, 3.2). Furthermore, the operating unit (1) has a first stop (8) and a second stop (9) for the at least one pin (6). The first stop (8) and the second stop (9) are arranged relative to the shaft (3.1, 3.2) such that the shaft (3.1, 3.2) is rotatable between a first wave position in which the at least one pin (6) strikes the first stop (8) and a second wave position in which the at least one pin (6) strikes the second stop (9).