Elevator Hazard Warning Sensing for Car-Counterweight Inspection Safety

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Solution Overview

Problem

Elevator systems lack effective safety measures to prevent mechanics from accidentally contacting the counterweight during inspection mode, particularly when the elevator car is within a predetermined distance from the counterweight.

Innovation Solution

An approaching hazard warning system with a range finding sensor and controller that detects the distance between the elevator car and counterweight, executing responsive actions such as slowing or stopping the elevator car and providing audible alerts when the distance falls below certain thresholds, and using a relay to stop the elevator car if necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an approaching hazard warning system is implemented to prevent mechanics from contacting the counterweight, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical safety systems with electronic sensing and control components. A range finding sensor (optical/electronic) detects the distance between the elevator car and counterweight, and a controller processes this data to trigger warnings or stop the elevator, substituting mechanical interlocks with electronic hazard warning system

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The controller acts as an intermediary between the range finding sensor and the elevator motor/brake system. It receives sensor data, processes the distance information, and executes responsive actions (visual/audible warnings, slowing, or stopping the elevator), thereby mediating the safety function without requiring direct mechanical connection between components

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a range finding sensor and controller are added to detect distance and execute responsive actions, then safety is improved, but cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The controller serves multiple functions: it processes range finding sensor data, determines when the elevator is in inspection mode, executes visual and audible warnings, controls motor power removal, and manages brake application. This multi-functionality consolidates what could be separate safety systems into a single controller, reducing overall system cost

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

Solution Approach 2:

The system uses the elevator's existing motor and brake mechanisms to execute safety actions. When the controller detects a hazard, it removes power from the motor and activates the brake, utilizing components already present in the elevator system rather than requiring additional dedicated stopping mechanisms

Inventive Principle:
Principle #25Self-service

3Reliability

If power is removed from the motor and brake is applied to stop the elevator, then safety is improved, but operation time increases

Engineering Contradiction:
ImprovesafetyVSAvoidoperation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system applies a graduated response based on distance thresholds. Instead of immediately stopping the elevator at any detected hazard, it first issues visual and audible warnings, then removes motor power, and only applies the brake when necessary. This partial action approach maintains safety while minimizing disruption to operation

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The controller executes preliminary warnings (visual and audible signals) before removing power from the motor or applying the brake. This preliminary action gives the mechanic time to react and stop the elevator manually if possible, reducing the need for forced stopping and minimizing operation time loss

Inventive Principle:
Principle #10Preliminary action

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

Ensures the safety of mechanics by preventing accidental contact with the counterweight through controlled deceleration and alerts, providing a low-cost, easily installable solution for elevator systems.

Implementation Method 1

a range finding sensor, operationally coupled to the warning system controller, and mounted to one of the elevator car, the counterweight and the hoistway wall

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP4671180A1Elevator system with approaching hazard warning system
Publication Date: 2025.12.31 OTIS ELEVATOR CO
  • EP4671180A1 patent drawingFigure 1
  • EP4671180A1 patent drawingFigure 2A~2C
  • EP4671180A1 patent drawingFigure 3

AI summary

An elevator system having: a hoistway; an elevator car movable within the hoistway; a controller operationally coupled to the elevator car; a counterweight coupled to the elevator car and movable within the hoistway; and an approaching-hazard-warning-system that has: a warning system controller; a range finding sensor, operationally coupled to the warning system controller, and mounted to one of the elevator car, the counterweight and the hoistway wall, wherein, while operating in an inspection mode, the warning system controller is configured to receive sensor data from the range finding sensor, detect when a distance between the elevator car and the counterweight is less than a stop distance while the elevator car and the counterweight are moving toward each other, and execute a first responsive action including one or more of slowing the elevator car by communicating with the car controller, stopping the elevator car and sounding a first audible alert.