Optical Elevator Speed Detection System

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Solution Overview

Problem

Current elevator speed and position detection systems are costly to install and maintain, particularly those using switches and cams or encoder-based systems.

Innovation Solution

A speed and position detection system utilizing optical sensors, such as LEDs or laser diodes, integrated with a processor to emit and process signals reflected off surface features within the hoistway, allowing for accurate and cost-effective measurement of elevator speed and position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If switches and cams are used to detect elevator speed, then speed detection reliability is improved, but installation cost and maintenance cost increase

Engineering Contradiction:
Improvespeed detection reliabilityVSAvoidinstallation cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical switch and cam system with an optical detection system using LEDs and photodetectors. The optical sensor array detects the position and speed of elevator components by measuring light reflection from coded patterns, eliminating the need for mechanical contact components and their associated installation and maintenance costs.

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

Solution Approach 2:

The patent uses optical coding patterns (reflective or absorptive) that create detectable signal variations without requiring physical switches. The coded patterns act as optical copies or representations of position information, allowing speed detection through optical signal processing rather than mechanical switching.

Inventive Principle:
Principle #26Copying

2Measurement precision

If encoder-based positioning systems are used to determine speed, then measurement precision is improved, but installation cost increases

Engineering Contradiction:
Improvespeed measurement precisionVSAvoidinstallation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive encoder-based positioning systems with a simpler optical detection system. The optical sensors detect coded patterns on the elevator car or guide rails, using light reflection properties to determine position and speed with sufficient precision without requiring complex encoder hardware.

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

Solution Approach 2:

The patent changes the detection approach from measuring physical position directly (encoders) to measuring optical parameters (light reflection intensity, timing of reflected signals). By detecting the timing and intensity of light reflected from coded patterns, the system derives position and speed information through parameter changes in the optical domain.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If optical sensors are used for speed and position detection, then installation cost is reduced, but measurement range is limited

Engineering Contradiction:
Improveinstallation costVSAvoidmeasurement range
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent uses multiple optical sensors arranged in arrays rather than a single sensor. The sensor array can detect coded patterns at different positions simultaneously, extending the effective measurement range. By segmenting the detection function across multiple sensors, the system achieves both cost-effectiveness and extended measurement capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces coded patterns (reflective or absorptive) as intermediaries between the optical sensors and the measurement target. These patterns enhance the detectability of position and speed information by creating distinct optical signatures, allowing the optical sensors to operate effectively over extended ranges while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Provides a reliable, inexpensive solution for determining elevator speed and position, ensuring safe operation and compliance with safety codes by using optical sensors for both short and long-range measurements.

Implementation Method 1

an optical sensor (62) capable of emitting a signal and receiving a reflected signal

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2593389B1Speed and position detection system
Publication Date: 2022.03.30 OTIS ELEVATOR CO
  • EP2593389B1 patent drawingFigure 1
  • EP2593389B1 patent drawingFigure 2
  • EP2593389B1 patent drawingFigure 3

AI summary

An elevator (20) associated within a hoistway (22) and having a speed and position detection system (62, 64, 70) is disclosed. The elevator (20) may include an elevator component (60) associated within the hoistway (22), an optical sensor (62) associated within the hoistway (22), an object (64) associated within the hoistway (22) in such a manner to be aligned in a path of the optical sensor (62), and a processor (70) operatively coupled to the optical sensor (62). The optical sensor (62) may be capable of emitting a signal (66) and receiving a reflected signal (68) of the emitted signal (66). The object (64) may have surface features (64a) that may reflect the signal (66). The processor (70) may be capable of processing the reflected signal (68) to provide an output indicative of a speed and position of the elevator component (60).