Elevator Car Virtual Safety Net for Handrail Overreach Detection

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Solution Overview

Problem

Existing elevator safety systems face challenges in detecting mechanics leaning over the top of the car handrail due to potential obstructions in the sensor's field of view from top of car components, which can obstruct the detection of potential hazards.

Innovation Solution

A sensor assembly is mounted around the elevator car to form a virtual safety net (VSN) using LIDAR, RADAR, or camera sensors, creating a set of perpendicular virtual sensing planes above the handrail system to detect objects, such as a mechanic's arm, and trigger the elevator safety chain to stop the car.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors are installed to detect mechanics leaning over the handrail, then detection capability is improved, but false positives may occur due to obstructions from top of car components

Engineering Contradiction:
Improvedetection capabilityVSAvoidfalse positive rate
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent transitions from traditional 2D sensor planes to a 360-degree spherical sensing arrangement. Multiple sensors are positioned at different elevations and angles around the handrail, creating a three-dimensional detection volume that encompasses the entire handrail perimeter. This dimensional expansion allows the system to detect objects from multiple perspectives simultaneously, improving reliability while maintaining precision through spatial differentiation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The sensing system is divided into multiple discrete sensor units distributed at different locations around the handrail. Each sensor monitors a specific sector or elevation zone, and the system integrates data from all segments to form a comprehensive detection picture. This segmentation allows the system to distinguish between actual hazards and normal components by analyzing patterns across multiple segmented detection zones.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If traditional sensors are used, then system simplicity is maintained, but detection is blocked by components in the field of view

Engineering Contradiction:
Improvesystem simplicityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sensor assembly is designed as a multi-functional unit that combines multiple sensor types (e.g., LIDAR, cameras, proximity sensors) and multiple sensing functions within a single integrated structure. This universal sensor head can detect various object types (mechanics, tools, debris) using different sensing modalities, eliminating the need for separate specialized sensors while improving detection reliability through redundant measurement capabilities.

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

3Area of stationary object

If sensors are positioned to cover all areas, then detection coverage is improved, but system complexity and cost increase

Engineering Contradiction:
Improvedetection coverageVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Multiple sensor functions and detection capabilities are merged into a single integrated sensor assembly positioned at the top of the car. Rather than distributing separate sensors throughout the hoistway, the system combines LIDAR, optical cameras, and proximity sensing in one location, achieving comprehensive 360-degree coverage while simplifying the overall system architecture and reducing installation complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 system provides reliable detection of potential hazards with low false positives, ensuring the elevator stops when necessary, while being cost-effective and adaptable to various elevator layouts.

Implementation Method 1

A sensor assembly is mounted around the elevator car to form a virtual safety net (VSN) using LIDAR, RADAR, or camera sensors

Methodology Applied
Scientific EffectLIDAR: LIDAR

Implementation Method 2

A sensor assembly is mounted around the elevator car to form a virtual safety net (VSN) using LIDAR, RADAR, or camera sensors

Methodology Applied
Scientific EffectRADAR: Radar

Data Source

PatentEP4477601B1Top of car handrail virtual safety net
Publication Date: 2026.03.25 OTIS ELEVATOR CO
  • EP4477601B1 patent drawingFigure 1
  • EP4477601B1 patent drawingFigure 2
  • EP4477601B1 patent drawingFigure 3~4

AI summary

An elevator system, having: a hoistway, a pit and an elevator car; a sensor assembly, wherein the sensors are distributed about the elevator car and configured to form a virtual safety net (VSN) around at least a portion of a first area that is exterior to the elevator car; and an elevator safety, wherein the sensor assembly is configured to: monitor for a breach of the VSN by an object that is potentially human; and upon detecting the breach of the VSN by the object, opening the elevator safety chain and stoping the elevator car.