Elevator Control Maintenance Mode Positioning

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Solution Overview

Problem

Existing elevator systems lack a safe and convenient method for positioning the elevator car at a desired location within the hoistway for maintenance and repair, risking uncontrolled movements and unauthorized access.

Innovation Solution

The elevator system is controlled through a maintenance mode activated by a service panel or service tool, requiring a predetermined button operation to move the elevator car to a specific landing, ensuring the service person's control and preventing accidental or malicious movements, with distinct safety conditions for maintenance operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the elevator car is positioned at a specific location for maintenance without proper control mechanisms, then maintenance access is improved, but safety is worsened due to risk of uncontrolled movements

Engineering Contradiction:
Improvemaintenance accessVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary safety checks before allowing maintenance mode operation. The control system verifies that the elevator car is stationary and that safety conditions are met before enabling maintenance positioning, preventing uncontrolled movements from occurring in the first place

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system continuously monitors the elevator car position and movement status during maintenance mode, providing feedback to the service person. The system detects when the car reaches desired positions and provides signals to confirm safe stopping points, ensuring maintenance personnel can safely access the car

Inventive Principle:
Principle #23Feedback

2Reliability

If a service panel or service tool is used to activate maintenance mode with predetermined button operations, then unauthorized access is prevented, but device complexity is increased

Engineering Contradiction:
Improveaccess controlVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The service panel and service tool serve multiple functions: they activate maintenance mode, control elevator car positioning, monitor safety conditions, and provide feedback signals. This multi-functionality reduces the need for separate dedicated devices for each maintenance task, balancing access control requirements with system simplicity

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

Solution Approach 2:

The service tool acts as an intermediary between the service person and the elevator control system. It provides a user-friendly interface with predetermined button operations that translate simple user actions into complex control sequences, masking the underlying system complexity while maintaining secure access control

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the elevator car moves to a predetermined distance from landings automatically, then positioning precision is improved, but loss of service person control is worsened

Engineering Contradiction:
Improvepositioning precisionVSAvoidservice person control
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The control system dynamically adjusts the level of automation based on the maintenance task requirements. The service person can select from different positioning modes: fully automatic positioning at predetermined distances from landings, or manual control with guidance. This dynamic adaptability allows the system to provide precise positioning when needed while maintaining service person control when preferred

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3798172B1Controlling movement of an elevator car of an elevator system
Publication Date: 2021.12.08 OTIS ELEVATOR CO
  • EP3798172B1 patent drawingFigure 1
  • EP3798172B1 patent drawingFigure 2~3
  • EP3798172B1 patent drawingFigure 4~5

AI summary

Elevator system (2) comprising: a hoistway (4) extending between a plurality of landings (8); at least one elevator car (6) configured for moving along the hoistway (4) between the plurality of landings (8); an elevator drive (5) configured for moving the at least one elevator car (6) along the hoistway (4); and an elevator control (9) configured for controlling the elevator drive (5). The elevator control (9) is configured for selectively operating in a normal operation mode or in a maintenance mode. The elevator control (9) is further configured for carrying out the following sequence of steps: (a) switching the elevator control (9) into a maintenance set-up mode in response to receiving a maintenance mode set-up signal; (b) when switched into the maintenance set-up mode and in response to receiving an input signal, controlling the elevator drive (5) for moving the elevator car (6) in accordance with the normal operation mode to a position specified by the input signal; (c) when the elevator car (6) has reached the specified position, switching into the maintenance mode in response to detecting an opening of at least one door (10, 11) providing access to the hoistway (4); (d) in response to detecting that a predefined call button (17a, 17b) has been operated for at least a predetermined period of time, controlling the elevator drive (5) for moving the elevator car (6) in accordance with the maintenance mode.