Elevator Safety Brake Backup Power for Low-Pit Rescue

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Solution Overview

Problem

Existing elevators with low pit and/or headroom face challenges in ensuring safety during power failures, as existing safety devices are not operational without main power and may hinder rescue operations, and manual intervention or additional rescue devices increase complexity and cost.

Innovation Solution

An elevator arrangement with an electromechanical safety device that includes a reserve power source to maintain operation during power loss, preventing car movement to unsafe positions and allowing rescue via controlled movement using the reserve power, and detection systems to prevent brake release in risky situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electromechanical safety device is used to prevent elevator car movement to unsafe positions, then safety is improved, but the device becomes non-operational during power failures and may hinder rescue operations

Engineering Contradiction:
ImprovesafetyVSAvoidrescue operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A reserve power source is provided that is preliminarily configured to supply power to the electromechanical safety device when normal power is cut off. This preliminary preparation ensures the safety device remains operational during power failures, allowing controlled movement of the elevator car to rescue positions without manual intervention or additional rescue devices.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If manual intervention or additional rescue devices are provided to enable rescue during power failure, then rescue capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improverescue operationVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The reserve power source serves multiple functions: it powers the electromechanical safety device during power failures to enable controlled rescue movement, and can also power the brake release device for controlled lowering of the elevator car. This multi-functionality eliminates the need for separate manual intervention mechanisms or additional rescue devices, reducing overall system complexity.

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

3Reliability

If the safety device prevents movement of the elevator car above predetermined upper position and below predetermined lower position, then safety is improved, but rescue becomes difficult when the car is stopped between landings during power failure

Engineering Contradiction:
ImprovesafetyVSAvoidrescue operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The electromechanical safety device is dynamically controlled by receiving control signals from the control device. During normal operation, it prevents movement to unsafe positions. During power failures, the reserve power source enables the control device to send signals that temporarily modify the safety device's behavior, allowing controlled movement to rescue positions while maintaining safety constraints. This dynamic adaptability resolves the contradiction between safety prevention and rescue enablement.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4457168B1Elevator arrangement and method of operating elevator
Publication Date: 2026.03.25 KONE OYJ
  • EP4457168B1 patent drawingFigure 1
  • EP4457168B1 patent drawingFigure 2
  • EP4457168B1 patent drawingFigure 3

AI summary

The elevator arrangement comprises an elevator shaft (10), an elevator car (11) that is configured to be moveable in a vertical direction along the elevator shaft (10), an electromechanical safety device (1) to which safety device (1) electrical power is supplied during operation of the elevator, and which safety device (1) is configured to be triggered when power supply to the safety device (1) is cut off, wherein triggering of the safety device (1) is configured to prevent movement of the elevator car (11) above at least one predetermined upper position and/or be-low at least one predetermined lower position, and a reserve power source (5), wherein the arrangement is configured to allow power supply from the reserve power source (5) to the safety device (1) for allowing moving of the elevator car (1) above the at least one predetermined upper position and/or below the at least one predetermined lower position when normal power supply to the safety device (1) is cut off.