Movable Elevator Apron for Hoistway Access and Fall Safety

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Solution Overview

Problem

Elevator aprons pose a barrier to accessing the hoistway for maintenance and repair, while safety requirements necessitate blocking access when the elevator car is not aligned with landings, limiting space and complicating emergency situations.

Innovation Solution

A movable apron system that transitions between a blocking position and an access position, allowing service personnel to enter the hoistway when the elevator car is near the lowest landing, using telescopic extensions or pivoting mechanisms with locking and sensing systems to ensure safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the apron is positioned to block access to the hoistway, then safety against falls is improved, but access for maintenance and repair deteriorates

Engineering Contradiction:
Improvesafety against fallsVSAvoidaccess for maintenance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The apron is designed as a movable barrier that can transition between a blocking position (extending downward to prevent falls) and an retracted position (allowing access to the hoistway). This dynamic configuration enables the same structure to fulfill both safety protection and maintenance access requirements at different operational states.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the apron is retracted to allow access to the hoistway, then ease of operation is improved, but safety protection deteriorates

Engineering Contradiction:
Improveaccess to hoistwayVSAvoidfall hazard
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system incorporates sensors that detect the elevator car's position relative to landings and automatically control the apron's movement. When the car is properly positioned at a landing, the apron is retracted to allow access; when misaligned, the apron extends to block access, preventing falls. This feedback mechanism ensures safety conditions are met before enabling access.

Inventive Principle:
Principle #23Feedback

3Reliability

If a fixed blocking apron is used, then safety is improved, but device complexity increases due to space requirements

Engineering Contradiction:
Improvesafety protectionVSAvoidspace requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of providing separate fixed blocking structures at multiple locations, the invention uses a single movable apron that can be positioned as needed. This dynamic approach reduces the overall space required compared to having fixed blocking aprons at every potential access point, while maintaining continuous safety protection.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3257803B1Elevator car and elevator system
Publication Date: 2019.11.13 OTIS ELEVATOR CO
  • EP3257803B1 patent drawingFigure 1
  • EP3257803B1 patent drawingFigure 2a~3b
  • EP3257803B1 patent drawingFigure 4a~4c

AI summary

An elevator car (6) which is configured for traveling along a hoistway (4) extending between a plurality of landings (8a, 8b, 8c), comprises an apron (20) arranged below the elevator car (6). The apron (20) is movable between at least two positions including: a blocking position in which the apron (20) extends downward from a bottom (9) of the elevator car (6) blocking access to the hoistway (4) through an area below the elevator car (6); and an access position, in which the apron (20) allows access to the hoistway (4) through an area below the elevator car (6).