Grounding Roller for Elevator Car Static Charge Dissipation

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Solution Overview

Problem

Elevator systems without conductive connections to the building shaft experience static charge buildup due to friction and magnetic fields, leading to voltage peaks during discharge, which can damage electrical components and pose health risks, especially when passengers enter or exit, and create communication issues due to differing electrical potentials.

Innovation Solution

An elevator system with a first roller providing a permanent conductive connection between the car and the guide rail, designed as a grounding roller with specific electrical resistance and materials to prevent voltage peaks and ensure stable electrical contact, using conductive additives in the roller's running body and a resilient mounting system to maintain contact without excessive mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If no conductive connection is provided between the elevator car and the guide rail, then the car structure remains simple and manufacturing is easier, but static charge builds up during travel causing voltage spikes that damage electrical components and pose health risks

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a grounding roller as an intermediary element between the elevator car and the guide rail. This roller provides a controlled conductive connection that allows static charge to be discharged to ground potential, preventing dangerous voltage spikes while maintaining mechanical simplicity. The grounding roller acts as a mediator that resolves the contradiction by enabling safe charge dissipation without requiring complex conductive structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a conductive connection is provided between the elevator car and the guide rail, then static charge buildup is prevented, but the device complexity increases due to additional grounding components

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The grounding roller serves multiple functions simultaneously: it provides mechanical guidance for the elevator car, enables conductive connection for static charge dissipation, and acts as a grounding path to earth potential. By combining these functions into a single component, the patent reduces device complexity while maintaining reliability, as the same structure that guides the car also handles the electrical grounding function.

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

3Reliability

If the roller is made highly conductive to prevent charge buildup, then electrical safety is improved, but the roller may experience excessive mechanical stress and wear

Engineering Contradiction:
ImprovereliabilityVSAvoidstrength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The grounding roller is constructed as a composite structure with a conductive core (such as metal) surrounded by a resilient or耐磨 coating (such as rubber or plastic). This composite design allows the roller to maintain high electrical conductivity through the core while the outer layer provides mechanical protection, reduces wear, and cushions against excessive forces from the guide rail, thus balancing electrical safety with mechanical durability.

Inventive Principle:
Principle #40Composite materials

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 effectively prevents static charge buildup and voltage peaks, ensuring safe and reliable electrical operation and communication by maintaining a stable, defined potential between the elevator car and the guide rail, even during movement and changes in direction.

Implementation Method 1

the first roller is designed as a grounding roller... a permanently electrically conductive connection between the car and the guide rail is provided via the first roller

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

This is due, firstly, to the friction of the plastic rollers against the guide rails

Methodology Applied
Scientific EffectTriboelectric effect: Triboelectric Effect

Implementation Method 3

Secondly, the magnetic fields of the linear drive also cause charge separation in conductive elements of the car

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3924283B1Elevator system with grounded elevator car
Publication Date: 2023.11.08 THYSSENKRUPP ELEVATOR INNOVATION AND OPERATIONS GMBH
  • EP3924283B1 patent drawingFigure 1
  • EP3924283B1 patent drawingFigure 2~3
  • EP3924283B1 patent drawingFigure 4~6

AI summary

The invention relates to an elevator system comprising at least one elevator car (28) that can be moved in an elevator shaft along a guide rail (52). At least one first roller (54) is arranged between the elevator car (28) and guide rails (52), said first roller (54) being designed as a grounding roller. In this way, the elevator car (28) is prevented from being electrostatically charged during travel.