Elevator Drive Unit Monitoring Device for Unauthorized Lifting Prevention

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Solution Overview

Problem

Existing elevator systems lack effective monitoring mechanisms to prevent unauthorized lifting of the elevator car or counterweight, which can lead to dangerous situations, especially when the counterweight is stuck or resting on buffers, potentially causing the elevator car to fall back or the counterweight to be lifted undesirably.

Innovation Solution

A monitoring device is integrated into the drive unit, utilizing at least one spring element as a force accumulator and a sensor to detect any lifting of the drive unit, which automatically switches off the motor when the vertical load is reduced, ensuring safety by preventing unauthorized lifting and slackness detection in the suspension means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the counterweight is stuck in the shaft or hits the buffer, then the support means becomes loose or slack, but the traction of the suspension element on the traction sheave remains sufficient for the drive unit to lift the empty elevator car, creating a dangerous situation

Engineering Contradiction:
Improvesafety of elevator systemVSAvoidunauthorized lifting of elevator car
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The monitoring device detects changes in the vertical position of the drive unit before unauthorized lifting can occur. By continuously monitoring the position and detecting when the drive unit moves vertically (indicating load release), the system takes preliminary action to switch off the drive motor, preventing the dangerous situation from developing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses sensors to provide feedback about the vertical position of the drive unit. When the sensor detects that the drive unit has moved vertically (indicating the suspension means has become slack), this feedback triggers the switching-off mechanism, creating a closed-loop safety system that responds to actual system state changes

Inventive Principle:
Principle #23Feedback

2Reliability

If a monitoring device is installed to detect lifting of the drive unit, then safety is improved, but the device complexity increases

Engineering Contradiction:
Improvesafety monitoring capabilityVSAvoidcomplexity of drive unit
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring device is designed to be universally applicable to different elevator systems. The sensor and switching mechanism can be integrated into various drive unit configurations without requiring system-specific customizations, reducing overall complexity through standardization

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

Solution Approach 2:

The monitoring device uses the existing vertical movement of the drive unit as its own sensing mechanism. Rather than requiring complex external monitoring systems, the drive unit's natural movement under load changes serves as the trigger signal, making the system self-monitoring and reducing external complexity

Inventive Principle:
Principle #25Self-service

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 simplifies modernization of elevator systems by enabling easy replacement of the drive unit and installation of a safety device, preventing dangerous conditions by ensuring the drive unit is switched off when the load is released, thus maintaining safety and compliance with safety standards.

Implementation Method 1

at least one spring element acting as a force accumulator being provided on the drive unit

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least one spring element acting as a force accumulator being provided on the drive unit, which the drive unit at a Relief of the support means

Methodology Applied
Scientific EffectHooke's Law: Hooke's Law

Data Source

PatentEP1953108B1Lift and method for surveillance of this lift
Publication Date: 2013.04.03 INVENTIO AG
  • EP1953108B1 patent drawingFigure 1
  • EP1953108B1 patent drawingFigure 2
  • EP1953108B1 patent drawingFigure 3~4

AI summary

This drive unit (9) includes at least one monitoring device (28) for monitoring the unauthorized lifting of the elevator car. The drive unit (9) consists of a motor unit (14) and a deflection unit (17). If the counterweight supported by the deflection unit (17) rests, for example, on the pit buffer, the deflection unit (17) is relieved of its load and lifted by means of a spring element (22) of the monitoring device (28). A sensor (29) of the monitoring device (28) detects the movement of the deflection unit (17) and switches off the motor (30) of the motor unit (14) via a safety circuit.