Elevator Landing Door Switch Inspection via Voltage Difference

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Solution Overview

Problem

Existing elevator systems require manual and time-consuming inspections of door interlocks and landing door switches, especially in high-rise buildings, due to issues like poor contacts caused by dust adhesion and corrosion, which can lead to unforeseen accidents and increased maintenance burdens.

Innovation Solution

A door switch inspection device that calculates voltage differences between each landing door switch and the power supply voltage, comparing these differences to a threshold value to detect abnormal conditions, with voltage detection units at each hall station and a main controller transmitting alerts for maintenance inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual inspection of all door interlocks is performed, then abnormal conditions can be detected, but inspection time and maintenance burden increase significantly

Engineering Contradiction:

Improvedetection of abnormal conditionsVSAvoidinspection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical inspection with an automated electrical detection system. The main controller automatically detects the closed/open states of all landing door switches through electrical signals, eliminating the need for manual inspection while maintaining detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-diagnosis functionality where the elevator system automatically monitors its own door switch status. The main controller periodically checks the states of all landing door switches without external intervention, allowing the system to self-identify abnormal conditions.

Inventive Principle:

Principle #25Self-service

2Reliability

If all door interlocks are inspected manually, then complete coverage is achieved, but the burden on maintenance personnel increases

Engineering Contradiction:

Improvecomplete inspection coverageVSAvoidmaintenance burden

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary detection mechanism between the door switches and maintenance personnel. The main controller acts as an intermediary that automatically collects and analyzes the status of all door switches, presenting the information to maintenance personnel only when abnormalities are detected.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of repair

If a specific faulty door switch needs to be identified, then system recovery can be achieved, but much more time is required to examine all door interlocks

Engineering Contradiction:

Improvesystem recoveryVSAvoidtime to identify faulty switch

Core Design Contradiction:

Ease of repairVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the main controller continuously monitors the status of all landing door switches and immediately provides feedback when an abnormal condition is detected. The controller identifies which specific door switch is faulty and communicates this information, enabling rapid localization of the problem without examining all door interlocks manually.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual sequential inspection with automated parallel electrical detection. All door switch states are detected simultaneously through electrical signals, allowing immediate identification of the faulty switch location without time-consuming manual examination of each door interlock.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Automatically identifies abnormal conditions in landing door switches, reducing the burden on maintenance personnel by pinpointing faulty switches and enabling quicker recovery of the elevator system, thus enhancing safety and efficiency in inspections.

Implementation Method 1

a voltage detection unit (310) for detecting a voltage value at a switch contact of the landing door switch (4)

Methodology Applied

Scientific EffectVoltage detection: Ohm's Law

Implementation Method 2

calculating a voltage difference between the voltage value obtained from the highest floor and the power supply voltage and comparing the voltage difference with the threshold value

Methodology Applied

Scientific EffectVoltage difference calculation: Ohm's Law

Data Source

PatentEP3354614B1Automatic door switch inspection

Publication Date: 2023.04.05 OTIS ELEVATOR CO

Figure 1(A)~1(B)
Figure 2
Figure 3

AI summary

A door switch inspection device (11) for detecting an abnormal condition of a landing door switch (4) used in an elevator. Each of a plurality of landing door switches (4) is disposed on a corresponding landing door at each landing floor for detecting an open/closed state of the landing door. The door switch inspection device (11) includes a plurality of voltage detection units (A, B, C, ... N) connected to the ground side of their respective landing door switches (4) for detecting a voltage value of their respective landing door switches (4), and a switch contact monitoring unit (9) for detecting an abnormal condition of a landing door switch (4), which is carried out by calculating a voltage difference between two adjacent floors and comparing the voltage difference with a threshold voltage.